Simulator 21 Patches

New Features

Bug Fixes

Date

December 19, 2022

Bug Fixes

  • Transient Stability: Fixed error in HYG3 governor model when Cflag>0 and Td=0 with the handling of the ignored state due to Td=0.

June 6, 2022

Bug Fixes

  • Transient Stability: Modified documentation of Vramp and Cramp parameters of the CDC4 and CDC6 type DC Line models to reflect that they are in the units of pu/sec.
  • Transient Stability: When restarting a DC line in transient stability after inverter bypassing, the units on Vramp and Cramp were not being treated properly and the DC line would restart at an extremely slow manner which was not correctly. This has been fixed. Note: the restart after rectifier blocking was correct. Now both Vramp and Cramp ramping for both inverter bypass and rectifier blocking is correct.

April 26, 2022

Bug Fixes

  • Power Flow Solution: When using the option to "Use Loss Factor For DC Line tielines", it was possible for the metered direction of the metered point of the line to be handled incorrectly and thus mess up the ACE calculation and area interchange. This has been fixed.

March 2, 2022

Bug Fixes

  • Power Flow Solution: When determining the Setpoint Voltage Tolerance to use with generators regulating voltage, only generators with an available AVR range can be used for selecting the tolerance. If no range is available the tolerance will be 0.

February 9, 2022

Features and Improvements

  • Transient Stability: Modified the option under the Stability Case Info drop-down on the Add-ons Ribbon Tab to expend the feature to "Convert CMPLDW and CMLD model to CompLoad". Previously it did not convert the CMLD model into CompLoad models with components but now it will do that along with the CMPLDW models.
  • Bug Fixes

    • Transient Stability: Fixed error in the use of the three-phase induction motor model MOTOR_CMP when used as a load component in the CompLoad model. The under-voltage tripping and reconnecting blocks were not being properly applied so that tripping and reconnecting did not occur. This has been fixed.

January 25, 2022

Features and Improvements

  • Transient Stability: Added the option to Auto Insert Loads (only opening loads) Transient Contingencies in the Transient Stability tool.
  • Transient Stability: When selecting a Transient Contingency to Skip the entire row fields will grays out. This will help the user visually identify the skipped contingencies.
  • Bug Fixes

    • File Formats: PSSE RAW file generator records will be written out with WMOD = 1 when the FuelType =SUN (Solar) OR Unit Type = PV (Photovoltaic) within Simulator
    • Transient Stability: Modified the CMLD and CMLPDW model so that if a loading factor for a motor is set as 0.0, then we simply interpret as 1.0 instead. 0.0 causes divide by zero errors which don't make sense.
    • Transient Stability: Fixed a bug when Calculating Effective Impedance from Sequence Networks in the transient stability event for buses and branches. The issue is when the Ymatrix created with the sequence data is singular then it was creating an infinite impedance causing the simulation to stop. This has been fixed.
    • Transient Stability: Fixed a bug with SimAuto function TSGetContingencyResults. If the case was storing the results into Hard Drive the function wasn't returning any results. That problem is fixed and now it will return the requested results.

December 21, 2021

Bug Fixes

  • Transient Stability: Added transient result events for the REEC_D model when it blocks and unblocks the machine model.
  • Transient Stability: Fixed an error in that could occur when using the REEC_D electrical control model in combination with the REGC_B machine model when the REEC_D model blocks the machine model.
  • Transient Stability: Fixed a bug with VTGTPAT timers. If the Relay Pickup Time (RelayTP) is more than 30 seconds there were some errors in the timer. This was fixed and now the relay will act in the correct time.

December 1, 2021

Bug Fixes

  • Transient Stability: When closing and reopening a plot inside the PowerWorld User Interface, the default height of the plot was shrinking by several pixels each time. This has been fixed to maintain the previous size of the plot dialog.
  • Transient Stability: Fixed an issue with SCl2 and OEL2C models. With the time inverse functions: K[(Ipu/ITPF)^C -1], when the Ipu is negative that will lead to an undefined solution. When Ipu is negative it is treated as zero and the exponential function (Ipu/ITPF)^C will return 0 and basically the output of the inverse function is set to -K.

November 22, 2021

Bug Fixes

  • Power Flow Solution: Fixed error that can occur in rare situations when solving the power flow on a case that contains breakers, not using Integrated Topology Processing, and a portion of the system is islanded.

November 19, 2021

Bug Fixes

  • Transient Stability: For the REPC_A and REPC_B model, added features on August 31, 2021 to handle bad user-input when a branch is NOT specified in the input parameters. When this occurs, then previously we always treated P, Q, and I inputs to the model as 0.0. This was changed to instead use the output of the generator. However, there was a bug when PUFlag<>0 meaning the inputs were assumed on the model MVABase and the inputs were the PUFlag was not being handle properly when the branch was not specified and values of generator output were not scaled by MVABase. This has been fixed.

November 17, 2021

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): When loading an AUX file or editing a case information display the 3WXFormer fields for RegBusNumSec and RegBusNumTer, the setting of regulated bus number was not being processed correctly. This has been fixe
  • Auxiliary Files (SCRIPT and DATA Sections): For 3-winding transformers there was a misspelling in the variable name for
    3WXFMagnetizingG and 3WXFMagnetizingG which were spelled
    3WXFMagetizingG and 3WXFMagetizingG instead (notice missing n).
    These misspelling were fixed in Version 22, but Version 22 will also read the old misspelled variable names.
    In Version 21 the misspelling was left, but this patch will now also read the correct spelling so AUX files written in Version 22 can be read in Version 21.
  • Case Information Displays: When show the Area Tielines and adding fields to show the Zone information for the tieline, if the table contained a lot of Load tielines it could be very slow. This was because PowerWorld was returning a list of "ALL zones that belong to the Area of the load" or the "Area of the bus". This could be a long list and would be repeatedly calculated. This has been changed so that instead we return the "Zone of the Load" and the "Zone of the Bus" instead as this is more in keeping with what is done for AC branches which return the "Zone of the Near Bus" and the "Zone of the Far Bus"
  • Contingency Analysis: The contingency solution option to "Dynamically add/remove slack buses as topology is changed (Allow Multiple Islands)" CANNOT be set to allow multiple islands if it has previously been set to not allow multiple islands. This will be enforced when the contingency specific solution options are applied.
  • QV Curve Tool: The QV solution option to "Dynamically add/remove slack buses as topology is changed (Allow Multiple Islands)" CANNOT be set to allow multiple islands if it has previously been set to not allow multiple islands. This will be enforced when the QV specific solution options are applied.

November 9, 2021

Bug Fixes

  • Available Transfer Capability (ATC) Tool: Removed the change made in the 6/22/21 patch for the ATC (IL) then Full CTG solution method that set the new stepsize to (stepsize + stepsize/2) when the stepsize is negative and the monitored element is overloaded. This change does not work in all situations.

November 8, 2021

Bug Fixes

  • Contingency Analysis: If a new Custom Monitor was created after contingency analysis had already been run, the results for the Custom Monitor would not always show up if using the Solve Selected Contingency option. This has been fixed.
  • General: In TransLineCalc, fixed the conductor database to have the proper number of significant digits for the various conductor parameters.
  • Transient Stability: When tracking the Percent field of a transmission branch, the value in transient stability is always the percentage of the MVA Limit. Previously it was not clear that this was the case.

November 1, 2021

Bug Fixes

  • File Formats: Fixed a bug that could under very rare circumstances cause Simulator to hang or fail when opening older supported text file formats. This was not a problem with AUX files.

October 27, 2021

Bug Fixes

  • Contingency Analysis: If Contingency X resulted in a partial solution (some islands are solved while others are not) and the very next Contingency X+1 did not do anything (for example it opened a branch that was already open in the reference case), then Contingency X+1 would also report as a "Solved=Partial" instead of the correct "Solved=YES". This has been fixed.
  • File Formats: When loading a case saved using the Save Two Bus Equivalent option with Transient Stability that contained Supplemental Data containing objects that are not saved with the two bus equivalent, an access violation could result. This has been fixed.
  • QV Curve Tool: Fixed access violation that could occur when running QV analysis and no buses are selected for analysis.

October 22, 2021

Features and Improvements

  • General: No change made to the October 22, 2021 patch of Simulator Version 21.

October 21, 2021

Features and Improvements

  • Contingency Analysis Tool: Fixed an issue in Contingency Analysis. When Storing Results into Hard Drive if the file location didn't exist it was setting internally the file directory to nothing and it was causing the results to be lost when finishing the analysis. Now it will prompt an error for the user to fix the file directory before continuing with the analysis.

October 18, 2021

Bug Fixes

  • Available Transfer Capability (ATC) Tool: The ATC Multiple Scenario Results table is populated with information from the limiter with the lowest Trans Lim value from all limiters that have been iterated on. If none have been iterated on then it is populated from the limiter with the lowest Trans Lim value. It was possible if a reserve limit was hit during the initial part of the iterated process when all limiters are iterated on that the limiter chosen was the first one in the list and not necessarily the one with the lowest Trans Lim if none of the limits had been marked as being iterated on. This has been fixed.
  • Available Transfer Capability (ATC) Tool: When attempting to get a failed contingency solution to solve using SOLUTIONFAIL actions, remaining SOLUTIONFAIL actions would not be applied if the last action made no changes. This has been fixed.

October 13, 2021

Bug Fixes

  • Contingency Analysis: Injection group contingency actions for Change By or Set To that are Persistent could cause excessive POSTCHECK iterations to occur when no changes are being made. This has been fixed.
  • File Formats: Modified how fault impedance is specified when loading a type of fault from an OTGD file
  • Transient Stability: Fixed a how parameter checks on values exceeding the maximum value allowed for the parameter was handled when validating data in transient stability.

October 6, 2021

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): An error message will now appear in the message log when loading a blank interface element from an auxiliary file.
  • File Formats: Fixed access violation that could occur when loading a PWB file that contained blank unlinked interface elements.
  • User Interface Dialogs: Fixed bug on the interface definition portion of the Model Explorer. When choose a particular interface the subtabs for Load Open and Gen Open were not properly showing the list of actions.

October 1, 2021

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug where changing the SVC type of an SVC to type 2 or appending an SVC of type 2 using the AppendCase script command in an AUX file would cause an access violation.

September 28, 2021

Bug Fixes

  • Optimal Power Flow (OPF): fixed potential oscillation in the solution of the DC OPF solution when using a case with 1000s of contingency interfaces defined on a larger case.

September 27, 2021

Bug Fixes

  • Case Information Displays: Fixed error with using Difference Flows with CustomFloats and CustomIntegers.

September 21, 2021

Features and Improvements

  • File Formats: Added FaultType for BusFault and LineFault when reading a Transient OTGD file.
  • Bug Fixes

    • File Formats: When reading an OTGD transient file for elements that happened at the same time but a parameter (for example in a branch opening then NEAR and FAR End at the same time) was different it was not adding the event correctly. This has been fixed.

September 17, 2021

Bug Fixes

  • Transient Stability: Fixed a bug that when adding a new field in transient stability in a new version, when loading the results from hard drive into RAM was showing an empty column corresponding to that field in the TimePoint Results Table.
  • Transient Stability: Fixed initialization error when using an REGC_B machine model in combination of a type 3 wind turbine model using a WTGTRQ_A (or WTTQA1) model.
  • User Interface Dialogs: Fixed field translations on the Display Explorer.

September 16, 2021

Features and Improvements

  • Transient Stability: Modified REEC_D model so that the Thld2 parameter acts to freeze the value of Ipcmd instead of the value of Ipmax as is done in REEC_A model.
  • Transient Stability: Added the ability to read and write models ESST1C and ESST4C to a dyd file. The equivalent models in PowerWorld are ESST1C = ST1C and ESST4C = ST4C.
  • Bug Fixes

    • Transient Stability: There is a bug that resulted in an Access Violation if you try to right click the Signals table with no signals in the table in the Modal Analysis Form in Transient stability.
    • Transient Stability: Removed harmless but confusing event reporting in transient stability for out-of-service DC transmission line dynamic models.
    • User Interface Dialogs: Fixed inconsistencies when changing between per unit and percentage voltage changes when using the options to never report or always report voltage violations with contingency analysis.

September 10, 2021

Bug Fixes

  • Optimal Power Flow (OPF): In very rare situations for Interface definitions that contain many BRANCHOPEN InterfaceElements that result in the complete isolation of parts of the power system the calculation of the interface flow could become inaccurate. This could mess up calculations such as an OPF solution which uses the Interface MW flow to calculate the OPF solution. Internally, a numerical summation of very large values is done and that calculation was incorrectly using single-precision floats (7 significant digits). A user encountered an example where the equivalent of the subtraction of (123456789 - 123456789) was not returning 0.0 but instead what appeared to be random 2 digit number. This has been fixed by using double-precision instead to maintain enough significant digits to prevent this bug.

September 8, 2021

Bug Fixes

  • Oneline Diagrams: Left-clicking and dragging on top of a background line when in Run Mode should simply pan the oneline in the direction of the dragging. This worked for most background lines, but not if the background line had been created by loading from a Shapefile. This has been fixed.

September 7, 2021

Bug Fixes

  • GIC: Fixed some errors with trying to get results for a transient stability run of the transformer GIC.
  • Transient Stability: When creating an open transient contingency action for a branch, the One Phase Open option will no longer appear on the GUI dialog. This option has not been implemented and an action defined as this would act the same as an Open Both action.
  • Transient Stability: Fixed some errors in VHVDC1 implementation.

August 31, 2021

Features and Improvements

  • File Formats: Added ability to store values read from EPC file for a 2-terminal DC line for values not used in power flow solution:
    Rectifier Gamma Min, Rectifier Gamma Max, Inverter Alpha Min, and Inverter Alpha Max. While these values are not used with the power flow solution, the value Inverter Alpha Min is used in the recently added CHVDC2 model. That value is not included in the DYD record for the CHVDC2 model, so we must carry it around with power flow data to properly read EPC/DYD file pairs.
  • Oneline Diagrams: Fixed how substation display objects use Default Drawing Values to highlight voltage limits. If showing the "Min kV of Highest Nom kV" or "Min PU of Highest Nom kV" fields within a substation display object, the color of this text will be the Limit Highlight Color specified with the Default Drawing Values if at least one bus in the substation is outside its voltage limits. If there is dynamic formatting in effect the dynamic formatting color will be used instead. The Limit Highlighting Used field was being ignored, but it is now being used to determine if the Limit Highlight Color should be used. The default color for the substation text will be used when the Limit Highlight Color is not used and in the absence of any dynamic formatting.
  • Power Flow Solution: Fixed bug that could prevent the DC converter equations from solving to a solution very close to the minimum firing angle at the rectifier. The solution may instead setting a transformer step 1 stepsize away a solution near the mimimum firing angle.
  • Transient Stability: Cleaned up the network boundary equation for the converters of a VSCDCT VSCDCLine dynamic model.
  • Transient Stability: Modified the bad input data treatment when the branch P, Q, or I measurement are needed for an REPC_A model but a branch is not specified. Previously we just assumed all flow measurements were 0.0, but this has been changed so that in this situation we use the output of the generator instead.

August 27, 2021

Features and Improvements

  • Case Information Displays: Updated description for the Int MW field for areas, zones, etc. to better reflect how it is calculated.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When interpreting interface elements for loads using a single string meant to represent the label of the load, it was possible for it to mis-identify the load if the user was using a label for a load that was exactly the same as either a bus number or "name_kv" of a bus in the system and that bus had a load. This has been fixed.
    • Transient Stability: Modifying how blocking is treated in the VHVDC1 voltage source converter DC line model. Also cleaned up the network interface equations for the VHVDC1 VSC DC Line dynamic model

August 20, 2021

Bug Fixes

  • Transient Stability: Any OEL connected to Exciter ESST4B now has the ability to automatically modify the VOEL output so that initial limit violation can be prevented when the "Modify Limits" option is chosen in Transient Stability options. This modification will only occur if an OEL can initialize to Activation Status = Idle.
  • Transient Stability: When Qref=0 for OEL4C, internally the program sets Qref to current Qmax from the power flow records. This was already being done. However, for generators that have an internal step up transformer, Qmax needed to be transformed to the generator terminal-side. This modification has now been made.
  • Transient Stability: Bug fix for generating plots of fields only if they are stored in Hard Drive (storing to RAM is okay). Users might have observed that incorrect values were being plotting fields of certain devices. For example, plotting the "OEL Other 1" field for a Generator which does not actually have an OEL Active. The correct behavior is to not show any plot series on the generated plot, because the field itself does not exist for that generator. This issue is now fixed.

August 18, 2021

Features and Improvements

  • Available Transfer Capability (ATC) Tool: For the TransferLimiter object type, the variables for ATC_ExtraMonitor and ATC_ExtraMonitorSens can now be identified by the object identifier for the object they are monitoring instead of the location number. Example: ATCExtraMonitor:"Branch '1' '2' '1'".
  • Bug Fixes

    • Oneline Diagrams: After the file save is complete when using the ExportOneline script command, the oneline will now be returned to the options and view that were in place prior to issuing the command.
    • Transient Stability: Fixed the Exciters EXAC1, EXAC1A, EXAC2, EXAC8B and REXS to work properly when the Hard Limit is implemented with the OEL1 Over excitation model. Previously the EFd limits were calculated without taking into effect of the function Fex in the output of the Exciter.

August 16, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): For ATCWriteToText script command, messages will appear in the log if any invalid field variable names are specified.
  • Available Transfer Capability (ATC) Tool: Added new option for handling branch and interface limit violations in the PV tool. There is now an option called "Stop in Base Case Only" that can be applied to either type of violation. When this is used, only base case limit violations can cause a scenario to be critical. Any limit violations that occur for contingency scenarios will be ignored.
  • Transient Stability: Modified the HYGOV, HYGOVR, HYPID, HYGOV4, HYG3 hydro governor models so that when the the hydro model can not achieve the initial Pmech we automatically increase the At (turbine gain) value to allow initialization. This had already been added to the initial release of PowerWorld Simulator 22, so this only impacts Version 21.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When loading a Custom Monitor from an auxiliary file or pasting from Excel and the Object Name is not specified as blank and cannot be found, set the Enabled field to NO so this custom monitor is ignored. When the Object Name is blank this means that all objects of the specified type will be monitored. Do not want all objects monitored by default if the particular object cannot be found.
    • Transient Stability: Fixed a bug when the loads do not have a distributed generation model but do have distributed generation load defined with the load and the total load was negative. It was causing some transient solution problems. Also a warning will be presented when the distribution generation do not have a transient model but have distributed generation with the load.

August 9, 2021

Features and Improvements

  • Transient Stability: In VHVDC1 the Pacref is treated as equal to 0.0 when either converter is blocked. This modification also changes it so that Idcref is also treated as 0.0 when either converter is blocked. This only mattered when using the dPmax and dPmin values to enforce a rate limit on the change in Pacref.
  • Transient Stability: Added the signals 'Iact', 'Ibias', 'Terr', 'IERRinv1' and 'IERRinv2' for the OEL2C model Other Fields.
  • Bug Fixes

    • File Formats: Fixed access violation that would occur when loading an EPC file which contained no Shunt record section.
    • Transient Stability: More robust initialization for OEL2C.
    • Transient Stability: When an OEL model was getting VFE from generators as an input it was not getting the VFE correctly.

July 29, 2021

Bug Fixes

  • User Interface Dialogs: Fixed a bug with the Generator Display dialog in Edit Mode when modifying the Voltage Tolerance it was setting the Voltage Setpoint to the Voltage Tolerance when you close the dialog or hit the Save button.

July 23, 2021

Features and Improvements

  • File Formats: Fixed a bug with the MBL in the WECC switch file that wasn't creating the transient contingency. Now it will create the MBL transient contingency.

July 22, 2021

Bug Fixes

  • User Interface Dialogs: Fixed errors on the Direction dialog

July 16, 2021

Features and Improvements

  • Transient Stability: Improved network convergence when CHVDC2 model uses the commutation failure features.
  • Transient Stability: Added ability to feed in the auxiliary current signal into the CHVDC2 model

July 15, 2021

Features and Improvements

  • User Interface Dialogs: Removed the Close button on the Keyboard Shortcuts dialog because it didn't do anything. The X to close the dialog does everything that needs to be handled before the dialog is closed.
  • Bug Fixes

    • General: Fixed an issue where downgrading from a later patch release to an earlier patch release would break the Simulator installation causing the main executable to not be replaced by the earlier version executable.

July 9, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added LoadAXDFromAXD("filename", CreateIfNotFound) script command that will allow a display auxiliary file (AXD) to be loaded via this script command that is part of another display auxiliary file (AXD).
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: When doing an ATC calculation, a contingency that completely isolates either the buyer or seller will be ignored by the ATC calculation.

July 7, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added script command ATCWriteScenarioLog("filename", AppendFile, filter) that will write the detailed log information for ATC Multiple Scenarios.
  • General: When a case has been modified a prompt to save the case will appear by default if opening another case, open a new blank case, or closing Simulator. If this happens while the contingency dialog is open and the system state is not in the contingency reference state, another prompt appears asking if the contingency state should be saved. There is now an option to Cancel so that the original action that led to the prompt will be abandoned and allow the case to be saved as the modified base case and not the contingency state.
  • General: Added an option on the Simulator Options Environment page to "Prompt for saving modified case." This is checked by default. This is only stored in the registry and does not have auxiliary file support. When not checked the prompt for saving a modified case when opening a new case, opening a new blank case, or closing Simulator will not appear.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed an "ID collision" error that could occur when trying to move a three-winding transformer to different buses or change the ID.

July 1, 2021

Features and Improvements

  • Optimal Power Flow (OPF): Previously it was possible to attempt to solve the OPF/SCOPF with the Island-based AGC enabled. This should not have been allowed since it is using two different algorithms to dispatch the same generation. The code has been modified to present an error message 'Error: cannot solve OPF with Island-based AGC enabled.' when an OPF/SCOPF solution is attempted with Island-based AGC enabled.
  • Security Constrained OPF (SCOPF) Tool: Previously it was possible to attempt to solve the OPF/SCOPF with the Island-based AGC enabled. This should not have been allowed since it is using two different algorithms to dispatch the same generation. The code has been modified to present an error message 'Error: cannot solve OPF with Island-based AGC enabled.' when an OPF/SCOPF solution is attempted with Island-based AGC enabled.

June 30, 2021

Features and Improvements

  • Power Flow Solution: Added Message Log warning messages when a VSC DC Line is not properly configured to alert the user that the VSC DC Line is being ignored. As an example, if both converters are configured for MW control and error message will be generated that says "DCMode at From and To Converter are both the same. One side must be set to Power and the other to Voltage for the VSCDC Line to operate."
  • Security Constrained OPF (SCOPF) Tool: set hints for the SCOPF form options, and added longer descriptions for them
  • Bug Fixes

    • Contingency Analysis: Fixed bug properly displaying contingency injection sensitivity results in the Contingency Violations Display (LimitViol object type).
    • Optimal Power Flow (OPF): In some cases MWMarginalCostValues was not being saved as subdata when saving an AUX file
    • Power Flow Solution: If a generator had a negative MW output and it was using Boundary Power Factor control to set the Mvar limits, the Mvar limits would end up switched with the minimum being positive and the maximum being negative. This has been fixed.

June 29, 2021

Features and Improvements

  • Power Flow Solution: Added option to "Use Loss Factor For DC Line tielines". This will use the two-terminal DC line aLoss term to assign the metered point a fraction of the way along a two-terminal DC line. This term was always maintained previously but not used in the solution. This feature is supported in EPC files but not RAW files. PowerWorld Simulator now has a global option regarding whether to use this Loss Factor. When not using the Loss Factor (aLoss) we will default back to the MeteredEnd specification instead.
  • Bug Fixes

    • Transient Stability: When reporting total load for the entire case in transient stability when load models include a distribution equivalent, the totals were not correct. They were correct for individual loads, areas, zones, substations, etc... but not for the entire case. This has been fixed.
    • Transient Stability: Fixed an access violation when Saving Data from the Show/Save Selected Plot Data option in the Plot Designer. The error was happening when the plot included a PlayIn Signal. It was preventing the data from been saved. This error was fixed.

June 22, 2021

Bug Fixes

  • Available Transfer Capability (ATC) Tool: In ATC when using the (IL) then Full CTG solution method, corrected how a negative stepsize is handled when iterating on a failed contingency and the limiting element is overloaded at a step when the contingency does solve. When iterating on a failed contingency the stepsize is reduced by half if trying to find a transfer where the limiting element is not overloaded. This is incorrect if the stepsize is negative because the stepsize needs to become more negative to reduce the loading on the limiting element. The new stepsize is now (stepsize + stepsize/2) to make it more negative.
  • Available Transfer Capability (ATC) Tool: Fixed a couple of inconsistencies with the ATC solution when using the (IL) then Full CTG Solution.
    (1) When iterating on individual limiters with a contingency implemented, use the OTDF cutoff threshold instead of the PTDF cutoff threshold.
    (2) When iterating on individual limiters with a contingency and an infinite transfer level is reached during the step where the limiter is iterated on by linearly modeling the contingency, no longer continue to the step where the contingency is actually implemented. The result will report Iteratively Found as YES_INFINITE.
  • Contingency Analysis: Fixed infinite loop that might result when using Best Fit actions for contingencies and remedial actions.
  • Transient Stability: Fixed a divided by zero in HYG3 when (fRelec = 0) and (fRGate = 0).
  • Transient Stability: There was an access violation bug when no results are saved into RAM or Hard Drive but saving plots as a file. The problem is fixed.

June 17, 2021

Bug Fixes

  • Difference Case Tool: Fixed an access violation that would occur when saving present case topological differences over an entire model when some of those changes include new or changed three winding transformer star buses.
  • File Formats: When loading a FACTS device from a PTI RAW file which was translated to a switched shunt SVC with svsmo3 there was a divide by zero error occurring. This has been fixed.

June 15, 2021

Bug Fixes

  • Case Information Displays: Fixed a bug with Limit Monitors when creating a limit monitor the user puts a bus pair limit greater than A, B, C pr D. It was creating an access violation. This is now fixed.

June 11, 2021

Bug Fixes

  • Oneline Diagrams: Added error message to InsertConnectedBusesAction when trying to insert buses connected to a display bus based on it being linked to the specified data Bus object if no display objects can be found. This is not considered a fatal error.

June 10, 2021

Bug Fixes

  • Oneline Diagrams: In the AutoInsertBorders_Options object more than one border file can be specified to be applied at one time. This would not work if the specified borders included spaces before or after the comma delimiter. This has been fixed.
  • Transient Stability: When auto-inserting transient contingencies the multiple contingency grid was not refreshing and showing the new inserted contingencies. You needed to get out of the multiple contingency option and return back in order for the grid to refresh. That was fixed and now will refresh after auto-inserting contingencies.

June 9, 2021

Bug Fixes

  • Case Information Displays: Fixed bug that was making the Bus Fields LoadNetMW and NetMW conflict with one another resulting in the NetMW field (showing the net injection at the bus) to not work properly. (Same fix for LoadNetMvar and NetMvar).
  • Security Constrained OPF (SCOPF) Tool: Included two additional SCOPF options when saving the options to an AUX file: "Set Solution as Contingency Analysis Reference Case" and "Basecase Solution Method"
  • User Interface Dialogs: The Close and Help buttons on the SCOPF dialog would move to the right when increasing the size of the dialog. This has been fixed.

June 8, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): FixFlowArrowLineEnds and FixFlowArrowPosition script commands now have both input parameters as optional. When the Oneline name is not specified the script commands will be applied to the oneline for which the AXD file was applied. When the LayerName is not specified any flow arrow objects in any layer will be modified.
  • Bug Fixes

    • Transient Stability: Fixed a bug that when loading Advanced Options in Transient Stability plots, if the chart have more than one subplot it was causing an error. That error was fixed and the advanced options are loaded for the entire chart.

June 4, 2021

Features and Improvements

  • Power Flow Solution: Continued improvements with handling switched shunt ranges voltage setpoints that may conflict with generator setpoints.
  • Bug Fixes

    • Oneline Diagrams: When showing the oneline option to show out-of-service elements as dashed lines, the symbols for a transformer and series cap/reactors were not showing as dashed. The line segments up until the symbol were dashed, but not the symbol. This has been fixed so that the symbol also appears as dashed.
    • Transient Stability: Added exciter ESST1A_GE to be able to set a Hard Limit with the over excitation OEL1.
    • User Interface Dialogs: Fixed a bug with the Switched Shunts dialog that when the shunt is an svsmo3 was showing the current pu values multiplied by the Sbase for the Continuous Range and the Switching Range. Now it will show the values in pu value of the current. A better caption was inserted for making explicitly that the Continuous Range and the Switching Range is in pu of the current.

June 2, 2021

Bug Fixes

  • File Formats: ZBR Threshold value used when determining regulated buses for generators, switched shunts, and transformers was not being saved to PWB files. This has been fixed.
  • General: Added more error checking when copying and pasting so that errors don't result in access violations.
  • Oneline Diagrams: When showing the oneline option to show out-of-service elements as dashed lines, the symbols for a transformer and series cap/reactors were not showing as dashed. The line segments up until the symbol were dashed, but not the symbol. This has been fixed so that the symbol also appears as dashed.
  • Power Flow Solution: ZBR Threshold value used when determining regulated buses for generators, switched shunts, and transformers was not being saved to PWB files. This has been fixed.
  • User Interface Dialogs: When using an SVC type svsmo3 the Switching parameters are in Amps. We were using them in Amps in our code but the dialog was displaying the Switching parameters as Mvar. Now it shows Amps in the dialog for the switching parameter.

June 1, 2021

Features and Improvements

  • Transient Stability: modified treatment of D term for the new MOTORC to be the exponent for mechanical power.
  • Transient Stability: Added ability to read/write the ESAC8C model from a DYD record.
  • Bug Fixes

    • Case Information Displays: Fixed fields displaying improperly when in base case or difference display mode.
    • Case Information Displays: Fixed access violation that could occur when loading auxiliary file with DataGrid section that contains an empty ColumnContourInfo subdata section.

May 27, 2021

Features and Improvements

  • Transient Stability: Added a new load model named MOTORC which is a combination of the INDMOT1P with the same contactor, under-voltage, and thermal relays added as used in LD1PAC.

May 26, 2021

Features and Improvements

  • Contingency Analysis Tool: Modified the Best Fit Open contingency and RAS actions for Interfaces and Injection Groups. The algorithm attempts to find the smallest number of devices that can meet the desired amount. The more devices there are to consider the more time it takes to determine all of the possible combinations. If there are more than 20 devices, the devices will be sorted from high to low impact and examined in blocks of 20. If the entire 20 devices are needed to meet the desired amount all will be opened and then next block of 20 devices will be used to meet the remaining amount. This process continues until it is not required that a set of 20 devices are all required to meet the remaining amount. This block will use the combination algorithm to fine tune which devices are opened.
  • Transient Stability: Internal modifications to the LD1PAC model to split up the features of the under voltage, contactor, and thermal relays into pieces so that these can be applied to other load models
  • Transient Stability: modified SVSMO3 so that values of Kdbd < 1.0 are treated as Kdbd = 1.0

May 25, 2021

Features and Improvements

  • Available Transfer Capability (ATC) Tool: With iterated ATC methods added two new Iteratively Found strings: YES_INFINITE and FULL_INFINITE. These indicate that the PTDF/OTDF have become too small in the process of iterating on an individual limiter, and the transfer limit is treated as infinite. This had previously been indicated by the Trans Lim value being set to a very large number, and now these new strings give another clearer indication of this. Additionally, the highlight color for these types of limiters are lighter versions of yellow and blue used to indicate YES and FULL limiters, respectively.
  • Contingency Analysis Tool: Added script command CTGVerifyIteratedLinearActions that takes a single parameter, filename, for an input. This action will save a file that identifies which fields and conditional actions (remedial actions) are valid for use with the iterated linear analysis method for contingency and ATC analysis.
  • Bug Fixes

    • Contingency Analysis: When saving a PWB file and the contingency analysis dialog was open, the options as set on the dialog were not always being saved to the PWB file. This has been fixed.
    • Distributed Computation: When running distributed contingency analysis the Selected field for Contingency objects was being set to NO after the run. This has been fixed.
    • File Formats: When reading an EPC file and SVCs are allowed to control fixed shunts the linking to the fixed shunts was not being done correctly. This has been fixed.
    • Oneline Diagrams: Fixed a bug where the Snap To Grid setting was continually being reset to True
    • Power Flow Solution: When multiple lines that are not in series are closed and they have common bus terminals, angle smoothing does not work correctly. When this situation is encountered voltage estimates will be done instead on the buses that are involved in the line closures.

May 19, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): SaveData script command will now produce an warning message if an empty fieldlist is specified.
  • Case Information Displays: When creating a new Case Comment through script or aux file, a blank Time can be specified. Time is used as a key field so the current time will be increased in second increments until a unique time is found when loading multiple comments at the same time.
  • Case Information Displays: Added new summary information for the summation of Load Dist MW Max, Load Dist MW Min, Load Net MW, and Load New Mvar for the following aggregations: Bus, Area, Zone, Substation, Owner, InjectionGroup. Previously you could only get information about the Min/Max and Net values for loads by looking at individual load records or by creating your own calculated field.
  • File Formats: Bug fix for RAW file reading. Angle value was not being set correctly for node data read from a "SUBSTATION NODE DATA" section.
  • Transient Stability: Modified how network boundary equation solution is handled when bypassing a DC line using the CHVDC2 model. It now ensures that an extra solution occurs and bus frequency calculation is updated to prevent strange bus frequency calculation spikes when bypassing and unbypassing.
  • Bug Fixes

    • File Formats: Corrected some fields written for SVD devices in the EPC format export.
    • Transient Stability: Fixed error in how the short-term Rating Curve is applied to the SVSMO3 model. This was not allowing the SVSMO3 to supply a current a multiple of Ishrt higher for a short period of time when configured to do so.
    • Transient Stability: Modification to help with numerical integration of the INDMOT1P and INDMOT1P_PTR load models
    • Transient Stability: In PowerWorld parameters T1, T2, T3 and T4 are in seconds in DISTRELAY and DISTRELAYITR but in DYD files those parameters are in cycles in DISTREL. These paraemters are now properly converted accordingly when reading and writing those parameters from the DYD format

May 10, 2021

Features and Improvements

  • Transient Stability: Modified so that if the State Pitch (output) of WTGPT_B is stuck at a non-windup limit, then if the PitchControl state has a derivative pushing the output further against its limit the PitchControl state derivative will also be set to 0.
  • Transient Stability: Modified so that if the State Pitch (output) of WTGPT_B is stuck at a non-windup limit, then if the PitchComp state has a derivative pushing the output further against its limit the PitchComp state derivative will also be set to 0.
  • Transient Stability: Added the ability to read and write ESDC4C model to a dyd file.
  • Transient Stability: Modified the REEC_D electrical control model so that when it goes into a blocking mode it instantaneously forces the currents at the network boundary equations of the generator to go to zero.
  • Bug Fixes

    • File Formats: Removed old process that would update BranchDeviceType for a branch based on entries in CustomString:0, CustomString:1, or CustomString:2 after loading any aux file with branch data or using a SetData command on branch data. (This dated from 2006 and should have been removed years ago)
    • File Formats: Fixed failed power flow solutions that might occur when opening an EPC file while in edit mode.

May 3, 2021

Features and Improvements

  • Transient Stability: Added the ability to read and write ESST5C model to a dyd file.
  • Transient Stability: Added the ability to read and write ESST6C model to a dyd file.
  • Transient Stability: Added stator frequency dependence on the CIM5_PTR model
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): In the SendToExcel script command the ClearExisting parameter was not being read correctly if enclosed in double quotes. This has been fixed.
    • Contingency Analysis: When using transient stability models with power flow contingency analysis no changes should be attempted if the device or the device's bus is disconnected. Not checking the bus connection status could cause excessive POSTCHECK loops. This has been fixed.

April 30, 2021

Features and Improvements

  • General: Made modification to load ID assignment when merging buses. Previously the next unused ID was used even when the default was available. Now the default ID will be used if there is not already a load at the bus using the ID. This is consistent with how other objects like generators work.
  • Transient Stability: Added a new dynamic phasor model of a single-phase induction motor model named INDMOT1P
    https://www.powerworld.com/WebHelp/Default.htm#TransientModels_HTML/Load%20Characteristic%20INDMOT1P.htm
  • Transient Stability: Added a new motor model named INDMOT1P_PTR which is a simplified version of INDMOT1P, but includes the concept of progressive tripping and reconnecting
    https://www.powerworld.com/WebHelp/Default.htm#TransientModels_HTML/Load%20Characteristic%20INDMOT1P_PTR.htm
  • Transient Stability: Added a new motor model named CIM5_PTR which is the same as CIM5, but includes the concept of progressive tripping and reconnecting
    https://www.powerworld.com/WebHelp/Default.htm#TransientModels_HTML/Load%20Characteristic%20CIM5_PTR.htm
  • Bug Fixes

    • File Formats: Fixed a bug where Simulator will save a modified case to an incorrect location when opening a different case. Simulator would save the case to the same folder containing the newly opened case instead of the folder where the case was originally stored.
    • Transient Stability: Fixing reading, writing and setting MWCap from a dyd file for governors PIDGOV and WT4T.

April 29, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added column contour to the AUX format as a SUBDATA section on the DataGrid (string grid customization) object.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: When using iterated ATC methods the ramping is done relative to load and generator outputs in the base case so that generators will hit and back off limits consistently if transfer stepsizes change sign. When using injection groups as the source and sink it was possible that the ramping was being done relative to the total transfer already achieved rather than this base starting point. This could result in oscillatory behavior. This has been fixed.
    • Transient Stability: Fixed a bug in which the reading a dyd file a certain dc branch wasn't loading the dynamic ecpdc model. Now this is corrected and the epcdc model is read into transient stability.
    • Transient Stability: Fixed a bug with writing cmpldwg DGMBase parameter. When saving into dyd file and the load object DGMBase value is zero it was writing the load object DGMBase value as zero and not the transient model value.
    • Transient Stability: Corrected UEL model MNLEX2. The other fields: Activation Status and PQSig values were being output incorrectly.

April 27, 2021

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): The special keywords for @DATE and @TIME used with script commands were providing the opposite replacement. @DATE was giving the time and @TIME was giving the date. This has been fixed.

April 23, 2021

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed writing out auxiliary files so that they honor non-US regional Windows settings (i.e. using commas or periods as the decimal separator).

April 20, 2021

Features and Improvements

  • File Formats: RAW file reading for version 34 is now more lenient and allows the use of whitespace as a field delimiter.
  • Bug Fixes

    • Contingency Analysis: When loading a PTI CON file with contingency elements specified with WND for opening or closing a single winding of a three-winding transformer, the elements read after this entry could end up being incorrectly specified. This has been fixed.
    • Power Flow Solution: Fixed an access violation that would occur when loading a case with more than 8 buses in islands without generation attached to DC lines.
    • Transient Stability: Changed default parameters for VHVDC1 so that Iqmin2 and Iqmin3 are both negative values (as these should almost always be negative!).
    • Transient Stability: Fixed divide by zero when simulating VHVDC1 when Rdc = 0 in the power flow model and also L = 0 in the dynamic model.

April 13, 2021

Features and Improvements

  • Transient Stability: modified log message that says something like "1012 more ..." to say "1012 more MVABase changed" instead to make it more clear.
  • Bug Fixes

    • Transient Stability: Bug fix for OEL5C. State IntegratorTOEL was not being set.
    • Transient Stability: Made initialization of SCL2C more robust.

April 7, 2021

Bug Fixes

  • Oneline Diagrams: Fixed bug saving oneline diagrams. The program appeared to hang when saving oneline diagrams because of some unnecessary calculations for groups. We've fixed the problem by only doing calculation once.
  • Transient Stability: SCL1C is now more robust during initialization
  • Transient Stability: If Modify Limits is chosen in Transient Stability Options, and if a UEL1 model feeds into a exciter's HV gate, then UEL1 limits VUImin and VULmin are modified to prevent initial limit violations
  • Transient Stability: When choosing to either Copy or Print All Charts and Title Block, the Title Block was chosen then the bottom and right gray boundary edge on the image created was missing. This has been fixed.

April 2, 2021

Bug Fixes

  • Transient Stability: Fixed a bug with PSS3C not passing the correct parameters and causing an access violation.

April 1, 2021

Bug Fixes

  • Sensitivity Calculations: Fixed bug that was causing inconsistent TLR results after sequential power flow TLR calculations. The issue was the inconsistent inclusion of phase shifters in the TLR matrices. This has been fixed by checking if the matrices have been built with phase shifters and rebuilding if needed.

March 31, 2021

Features and Improvements

  • Case Information Displays: Added ability to specify generator voltage setpoint and setpoint tolerance in kV. Added generator field to show the RegBus Nom kV.
  • Case Information Displays: SendToExcel script command will no longer change the workbookname and worksheetname to uppercase.
  • Case Information Displays: Added TSContingency string grid table to the customizable tables. Now the customization of the Transient Contingency table can be saved.
  • File Formats: Added optional parameters filtername and AppendFile to the CTGWriteFilePTI script command. The filter is applied to the Contingency object type to specify the contingencies that should be saved to file. All contingencies are saved by default. Set AppendFile to YES to append to an existing file or NO to overwrite an existing file. File is overwritten by default.
  • File Formats: In various places where contingency files in the PTI CON format are saved in the GUI a prompt will appear if the file already exists asking the user if the file should be overwritten or appended.
  • Transient Stability: New transient stability fields for UEL/OEL/SCL. UEL/OEL dynamic models now have a transient stability integer field called "Activation Status". SCL dynamic models now have two transient stability integer fields called "UEL Activation Status" and "OEL Activation Status". Possible values are 0 (Idle), 1(Engaged) and 2 (Saturated).
  • Bug Fixes

    • Oneline Diagrams: Fixed a bug where Snap To Grid was not being returned to its previous value after being temporarily set to True
    • Sensitivity Calculations: When using consolidation with a full topology case, calculations for shift factors and PTDFs may not have been correct when using injection groups containing bus participation points as the source or sink. This has been fixed.

March 24, 2021

Features and Improvements

  • Case Information Displays: Added a new column for a Branch called "Transformer\Tap Ratio Change to Balance". When parallel taps are properly balanced, this field is blank. If this entry is not blank, then it shows the tap ratio which will balance parallel transformers. This is the same calculation done when solving a power flow and having the "Tap Balancing" enabled in the power flow solution options. Regardless of that solution option though, this field will show you the troublesome transformers.
  • Transient Stability: Added script command for clearing transient stability results from RAM of more or more transient contingencies
    TSClearResultsFromRAM(ALL/SELECTED/”ContingencyName”, ClearSummary, ClearEvents, ClearStatistics, ClearTimeValues, ClearSolutionDetails);

March 12, 2021

Features and Improvements

  • Case Information Displays: Added ability to put in a spaces to the area slack bus field and still have it clear out the setting.
  • Contingency Analysis Tool: Added support for reading and writing actions for opening or closing a single winding of a three winding transformer in a CON file.
  • File Formats: Added support for reading and writing actions for opening or closing a single winding of a three winding transformer in a CON file.
  • Bug Fixes

    • Power Flow Solution: Modified numerical precisions of some internal calculations to make extremely sensitive calculations such as when system nears voltage collapse slightly more consistent.

March 10, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added an optional parameter at the end of the special PROMPT section when specifying a filename in a SCRIPT command. That value can either be Continue or Abort. If you don't specify it this will be Abort (present behavior). If Continue is used, then we will simply skip the script command and continue reading the AUX file. If that is omitted or anything else is in that location we will Abort the entire read of the AUX file as is done now. Example syntax is as follows:
    LoadAux("", YES);
  • Auxiliary Files (SCRIPT and DATA Sections): Added support for reading future concise variable names that will be used in Version 22 for the following objects. This only impacts reading AUX files as Version 21 will continue to write the legacy variable names.
    CTGResultStorage, QVCurve, PVInterfaceResult, PWQVResultListContainer, PWPVResultListContainer, CTG_AutoInsert_Options, Equiv_Options, Fault_Options, IG_AutoInsert_Options, Limit_Monitoring_Options, LODF_Options, MessLog_Options, PTDF_Options, Scale_Options, Sim_Environment_Options, Sim_Simulation_Options, TLR_Options. Also all the difference case tool objects representing Removed*** objects
  • Difference Case Tool: When using an Aux Export Format to save Difference Case changes to file for objects that have at least one field that has changed, all objects were being saved if certain fields were included in the list of fields to save. Now only fields that are enterable and included in the difference case comparison will be considered fields that can change. These fields will still be written to the file but will not be included in the filtering.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed concise variable names for H6E model
    • Help: An error occurred when Exporting Case Object Fields prior to even opening a case. This has been fixed so you are not required to first open a case.
    • Sensitivity Calculations: Added some extra topology checking prior to running Shift Factor/TLR and PTDF calculations.
      Make sure that bus topology has been checked to determine if any buses have changed connection status. If the user has changed the status of branches and not run the power flow, this is necessary to calculate the correct results when using a Lossless DC method. When using the Full AC method a power flow solution is necessary after changing branch statuses to get the correct results.
    • Sensitivity Calculations: Prior to running LODF calculations through GUI tools or script commands for Single LODF, LODF Matrix, Advanced LODF Calculation, or LODF Screening make sure that bus topology has been checked to determine if any buses have changed connection status. If the user has changed the status of branches and not run the power flow, this is necessary to calculate the correct LODF values. Some LODF tools also provide a post-contingency flow estimate. For these to be correct the power flow will need to be solved.
    • Transient Stability: "Ramping Values to" By "Percent of Start" was not ramping to the correct end value. This bug was found while ramping generator MWSetpoint, but would have affected other device types also.
    • Transient Stability: TS Model MNLEX1 is now more robust for all possible situations during initialization.

March 4, 2021

Features and Improvements

  • Available Transfer Capability (ATC) Tool: Added concise variable names for ATC related objects: TransferLimiter, ATCScenario, ATCExtraMonitor, ATCFlowValue, ATCGeneratorChange, ATCLineChange, ATCLineChangeB, ATCInterfaceChange, ATCZoneChange. Also added these to Version 21 so they can READ files written with new names in Version 22. However, Version 21 will NEVER write these new variable names.
  • Transient Stability: (a) All Exciter Models and Excitation Limiter (OEL/UEL/SCL) Models now have compatibility checks (errors) during Validation before
    running Transient Stability, along with Auto-Correction that will disable the ill-configured OEL/UEL/SCL instances.
    (b) The Compatibility information can also be viewed in a table by viewing Exciter fields - "OEL Input Used", "UEL Input Used" and
    "SCL Input Used", and OEL/UEL/SCL fields - "Output Used".
    (c) If a OEL/UEL/SCL output signal feeds into a Summation Point of the Active Exciter, the min/max parameters of the OEL/UEL/SCL are validated, along with Auto-Correction to ensure an output signal of zero when operating within the bounds of the OEL/UEL/SCL.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: When using iterated ATC methods and the full transfer step will not solve, the stepsize is reduced by half in an attempt to get a solution. Prior to attempting the full stepsize, reserve limits on the source and sink are checked if MW limits are being enforced and the stepsize is reduced if source or sink limits would be exceeded. Now this reserve limit check is also done on the reduced stepsizes when the full transfer step will not solve.
    • Available Transfer Capability (ATC) Tool: When loading TransferLimiter objects from an AUX file for multiple scenario results using the concise auxiliary file format, the transfer limiters would be loaded correctly, but the ATCScenario was not being properly flagged as having "finished" its calculation so the results would not appear in the summary user interface on the ATC dialog. This has been fixed.
    • Available Transfer Capability (ATC) Tool: When using iterated ATC methods, AGCable generators that are in areas on control that are not the seller or buyer might still move because of changes in losses due to area to area transfers. These generators will now be adjusted relative to the starting dispatch at the beginning of the process.
    • Transient Stability: To match the behavior of Exciter model WT3E in PSLF, modified to make only acceptable values for the parameter "vltflag" of 0 or 1. WT3E1 has another option.
    • Transient Stability: Bug fix for Autosaving plots while running Distributed Transient Stability.

February 25, 2021

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Assigning data objects to supplemental data might not identify the correct supplemental data when assigning through AUX files.
  • File Formats: Fixed a bug that was occurring when exporting sequence data to SEQ files. Writing out the zero sequence impedances for three winding transformer devices was incorrect for newer SEQ files that allow two digit connection codes for transformers. Older SEQ files with single digit connection codes were unaffected.
  • Oneline Diagrams: Supplemental Data Field display objects were not supported in AXD files. They are now.
  • Oneline Diagrams: Supplemental Data Geo Data View objects were not supported in AXD or PWD files.
  • Oneline Diagrams: Fixed bug saving Geographic Data View Supplemental Data objects to a PWD file and being able to display these objects when the PWD is opened.
  • Transient Stability: Corrected bug with WT3E and WT3E1 that had an incorrect path with vltflg=0. For this case the connection should be directly to state1. This only impacted models with vltflg=0, which only occurred in the East grids, not the WECC. This did fix a lot of initial limit violation changes.

February 19, 2021

Bug Fixes

  • File Formats: Treat missing parameters in transformer records in PTI RAW files as optional and do not consider this a fatal error.
  • Transient Stability: Bug fix for Governor Model GGOV1 for divide-by-zero error when droop (r) = 0, and Pref value was being stored in results.

February 17, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Modified to give an error message in the log if an invalid ConditionType string is found for a Condition or ModelConditionCondition object.
  • Auxiliary Files (SCRIPT and DATA Sections): When reading an AUX file, modified to support the ConditionType field of != to mean not equal in a Condition or ModelConditionCondition object. PowerWorld will still always write out <> for this ConditionType but we now support reading !=
  • Auxiliary Files (SCRIPT and DATA Sections): Adding ability to remove an Area Slack Bus designation by deleting the Slack Bus number from the field. If AGC is enabled in the area, designating an empty slack bus will also turn of AGC.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When loading an AUX file which contains the contingency action to BYPASS or NOTBYPASS a series capacitor device, Simulator would only read this for a branch object that was marked as a "SeriesCap". This is allowed for any branch however, so we should read the action from an AUX file regardless.

February 15, 2021

Bug Fixes

  • Transient Stability: Fixed potential error in DC line equations in transient stability when a 2 terminal DC line did not have a dynamic model specified.
  • Transient Stability: There was an access violation when closing the case and was caused by REPC_B with Control Devices. That bug is fixed and no longer there is an access violation.

February 11, 2021

Features and Improvements

  • Available Transfer Capability (ATC) Tool: A new script command has been added to delete an index range of the ATCGeneratorChange or ATCInterfaceChange or ATCLineChange numeric changes
    ATCDeleteScenarioChangeIndexRange(Type, [Integer Range]);
    Type: can be either RL, G, or I
    [Integer Range]: inside brackets specify syntax for a comma-delimited list of integer ranges.
    Example: ATCDeleteScenarioChangeIndexRange(RL, [0-2, 5, 7-9]);
    This would remove the respective changes by index. Remember that these indices start from 0.
  • Bug Fixes

    • User Interface Dialogs: Fixed error in the parameter order for Exciter DC3A. During the simulation the parameter order was correct but not in the GUI or the Model Explorer. All of these was fixed.
    • User Interface Dialogs: When closing in a synchronous machine during a transient stability run an infinite loop could occur. This has been fixed.
    • User Interface Dialogs: Fixed a sign error in the ST6B and ST7B exciter models for the input of the OEL signal. The IEEE standard had a sign error in the block diagram that we incorrectly copied.

February 5, 2021

Features and Improvements

  • Bus View and Substation View Onelines: The Bus View option to "Show Only Breaker for Consolidate Branch" will only be checked by default if opening an EMS case. This will no longer be checked by default if simply opening a case that contains breakers.
  • Power Flow Solution: Added ability to specify as input the RegBus with a VoltageDroopControl object. If the value is specified, then all generators assigned to that VoltageDroopControl will automatically use this regulated bus. If the value is unspecified, Simulator will continue to create a unique Voltage Drop Control equation for each set of generators within the voltage droop control which share a regulated bus (or buses connected by low impedance branches).
  • Transient Stability: Adding Saving GE Stability Data with Options. The Options are Only Records Modified in Difference Case, a Bus Filter and Sort Gens, Loads and Switched Shunts by Bus; Area, then Bus; Zone, then Bus; Area, then Zone, then Bus; or Zone, then Area, then Bus.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: If running ATC Multiple Scenarios through script commands it was possible that the options for Transfer Limiters to Save, Max Limiters per CTG, Max Limiters per Element, and Max MW Limitation used defaults instead of user-specified values. This has been fixed.
    • File Formats: When reading the WECC transient fault definition file (*.swt), the FL record for faulting a line was reading the fault location as though it was in percentage. The FL record however lists the location as a decimal between 0.0 and 1.0, so we needed to multiply by 100.
    • Transient Stability: Several fixes to Governor Model UCBGT for more robust initialization, and to conform to the specifications as per CIGRE Technical Brochure on MODELING OF GAS TURBINES AND STEAM TURBINES IN COMBINED CYCLE POWER PLANTS (2003)
    • Transient Stability: Bug fix for Governor Model UCBGT and DER_A models. PI/PID controllers had the Kp and Ki values swapped.

February 1, 2021

Bug Fixes

  • Contingency Analysis: Fixed access violation that could result when saving an auxiliary file for contingency options and settings that include an injection group with unlinked participation points.
  • Transient Stability: Bug fix for Governor Model UCGBT -- error input in PID-block was modeled incorrectly. This was causing an unstable decline in the generator speed, even when the system-level dynamics had almost converged to a new steady-state. It is very likely that users would not have noticed this at the system-level during a simulation of less than 60 seconds. Instead, this problem was obvious at the system-level when running extended-duration simulation longer than 120 seconds.
  • Transient Stability: Made the bus filter used when saving an AUX file of all stability model also apply to the DistributionEquivalents and LoadModelGroups. It was only using Area/Zone filters as the special use of the bus filter had not been implemented for these objects.
  • Transient Stability: Fixed the enforcement of the Iql1/Iqh1 reactive power limit on Iqinj ror the REEC_A, REEC_B, REEC_C, and REEC_D.
  • User Interface Dialogs: Fixed access violation that would occur when opening the Aux File Browser.

January 29, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): The ClearFault and MultipleFault script commands have been changed to FaultClear and FaultMultiple, as the formatting of the commands is more consistent with other script commands. The ClearFault and MultipleFault legacy commands will still work if encountered.
  • QV Curves: Added new to QV curve to indicate where in the QV solution process to load in the QV curve power flow solution options. Previously they were always loaded at the beginning of the QV curve run BEFORE the contingency solution. Because of that, the Contingency solution options would always override the QV curve options when PowerWorld went to trace the QV curve after a contingency. There is now an option called "SolutionOptionWhen" that can be set to either "Before" or "After". By changing this option to "After", the QV curve options will instead by applied AFTER the contingency solution. The default option for this will remain "Before" for Simulator Version 21, but when Simulator Version 22 is released the default will be changed to "After".

January 27, 2021

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added a new script command named InterfaceFlatten(filtername); It takes as a parameter an Device Filter or advanced filter to specify which interfaces to flatten. A blank interface means to flatten all interfaces.
  • General: Added tool to flatten interfaces. This modifies an interface by bringing all the elements from any included interfaces into the interface that has been selected to be flattened. The tool is available in the right click menu. This was added to work around the limitation of not being able to calculate TLRs on nested interfaces.
  • Transient Stability: Added Exciter ST6C_PTI. This is largely the same as ST6C, but includes an extra derivative block in the PID controller as compared to the IEEE standard.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): The FuelCost field for a generator was made a priority field so that it is read before other fields. This was to fix a trampling bug when reading in an AUX file. If the FuelCost field was read in after a BidMWhr field, the BidMWhr fields would be scaled by the ratio of the NewFuelCost/ExistingFuelCost. This was causing a bug for a user who reported that the AUX file was not changing the GenBidMWHr field.
    • Transient Stability: When using an LCFB1 model in conjuction with an cross compound governor such as IEEEG1, then input per unit value of electrical power needs to be converted to per unit on the MVABase of the LCFB1 model. This has been fixed.
    • Transient Stability: Fixed access violations that could result when using a ModelPlane as part of transient stability RAS if either of the ModelExpressions defined for the ModelPlane do not exist.
    • Transient Stability: When using an IEEEG1 model which was assign to only 1 generator, if the K2, K4, K6, or K8 values were non-zero it could cause the normalization of the K1, K3, K5, and K7 values to be handled incorrectly. This has been fixed.

January 22, 2021

Bug Fixes

  • General: Alerts for new patches will now be tied directly to the last build date, rather than to the last patch description posted.
  • Transient Stability: Set the parameter order the same as PSS/E for Exciter AC8C.
  • Transient Stability: Set the parameter order the same as PSS/E for Exciter AC9C.
  • Transient Stability: In order versions of AC11C the parameter SW1 was initialized incorrectly and not to the current value of SW1.
  • Transient Stability: TS Model OEL2C is now more robust for all possible situations during initialization.
  • Transient Stability: Correctly write and read parameters to match PSS/E for Exciters DC1C, DC2C and ST1C. Reorder parameters to match PSS/E for exciter DC4C.
  • Transient Stability: Added Exciters ST5C and ST7C to be read and written in PSS/E format.

January 20, 2021

Bug Fixes

  • Transient Stability: Set the parameter order the same as PSS/E for AC1C to AC7C. Also fix non-windup limits for PI in AC7C and AC9C.
  • Transient Stability: TS Model OEL3C is now more robust for all possible situations during initialization.
  • Transient Stability: Added the ability to use the Area/Zone Filters when writing Feeder And LoadModelGroup For Loads when saving transient stability with options. before it was writing all of the loads in the case.
  • User Interface Dialogs: Fixed height of run mode bus dialog.

January 19, 2021

Bug Fixes

  • Available Transfer Capability (ATC) Tool: Fixed bug with ATC analysis that would report limiting elements that had a zero rating. This could only occur for lines that were closed as part of the associated contingency.
  • Contingency Analysis: Fixed bug with Model String Expressions where variables set to be evaluated in the contingency reference state were being evaluated in the contingency state instead.
  • Contingency Analysis: The caption of the Contingency Analysis Dialog\All Violations tab shows the name of the applied contingency if any. When moving away from the tab and then back, and then applying a second filter to the display the caption could become incorrect with both filter names appended. This has been fixed.
  • General: When calculating shortest path or path distance between objects now allow a line length of 0. Negative line lengths continue to be set to 1/10 of the minimum of all other lines that are allowed to be processed.
  • Transient Stability: TS Model OEL4C is now more robust for all possible situations during initialization
  • Transient Stability: TS Model UEL2 is now more robust for all possible situations during initialization

January 14, 2021

Features and Improvements

  • User Interface Dialogs: Added data maintainer to Area/Zone/Substation section of the Bus, Shunt, Gen, Line, and Load dialogs.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When loading TransferLimiters from an aux file and contingencies do not exist, create contingencies with the case specified for the name rather than all upper case.
    • Contingency Analysis: Return the system state to the failed power flow solution state during contingency analysis if there are SOLUTIONFAIL actions but none of them are implemented.
    • Transient Stability: Fixed a PI derivative in SCL1C model.
    • Transient Stability: The derivative of the PI integrator wasn't set to zero when at the limits for ST4C, ST6C and ST8C models.
    • Transient Stability: Corrected OEL5C to initialize to VOEL = Ibias, and also make sure that Ibias >= Vr(t=0) (from Exciter)
    • Transient Stability: Added ability to use Copy/Paste from Excel to define TSPlayInSignal data to create Playin structures. Also added case information displays which show a list of all PlayInInfo objects and another to show a list of all PlayInSignal objects.
    • Transient Stability: TS Model OEL5C is now more robust for all possible situations during initialization when OEL is (a) Not Limiting { VOEL = max }, (b) Limiting { min < VOEL < max}, and also (c) Fully Limiting { VOEL = min }
    • Transient Stability: TS Model UEL2C is now more robust for all possible situations during initialization when OEL is (a) Least Limiting { VUEL = min }, (b) Limiting { min < VUEL < max}, and also (c) Most Limiting { VUEL = max }

January 5, 2021

Features and Improvements

  • Transient Stability: UEL2 can now be read from and written to a dyd file.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: When using the Take Me To Scenario ATC option with multiple scenarios either through the GUI or script command, an initial ATC state was not being stored. This has been fixed so that if an ATC initial state has not already been stored, the system state in memory at the time these commands are called will be stored as the ATC initial state.
    • Available Transfer Capability (ATC) Tool: Prior to running ATC functionality that solves the power flow, system topology is now checked and voltage pre-processing is now done assuming the user may have made changes to the case without solving the power flow. Without these checks the ATC functionality may fail.
    • Case Information Displays: When deleting a plot series, axis group, or subplot from the case information display lists of those objects an error could occur. This has been fixed.
    • Power Flow Solution: For complex voltage droop control configurations with multiple generators at multiple buses remotely regulating a bus it was possible for the voltage droop control power flow convergence to be slow. This has been fixed.

December 21, 2020

Features and Improvements

  • Case Information Displays: Added a new field "CountLoadDistGen" for Area, Load, and Substation objects. This values returns a count of the number of load record in the respective grouping which has a non-zero DistMW OR a non-zero DistMvar value assigned.
  • File Formats: When loading a pwb the second line now also tells the patch date. As in:
    Opening Case AGL37_HW5.PWB
    Reading PWB File, Version 22 BETA (build 527, patch date 2020_12_18)
  • Transient Stability: Added support for a new VSCDCLine dynamic model named VHVDC1
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed an access violation in the TSAutoInsertDistRelay script command.
    • Case Information Displays: Fixed the text alignment for fields on Custom Case Information spreadsheet-like displays. Much of the text was always appearing as aligned to the left when numeric values should have been aligned to the right.
    • Case Information Displays: When the "Use Defined Names in Variable Name Locations" is used for fields on the Custom Case Information displays, then fields such as CalcField:14 can instead be defined as CalcField:My Calculation Name. This was causing an error in the Custom Case Information displays because the extra spaces would mess up the cell parsing for defining a cell. This has been fixed by exporting the field with single quotes around it as 'CalcField:My Calculation Name'.
    • Case Information Displays: Corrected spelling error in XF Nominal Tap Ratio column header for Branch object.
    • Difference Case Tool: In the Topological Differences from Base Case dialog, update the Removed objects count if using the option to include area/zone/owner filtering in the summary counts.
    • General: When determining the impact of contingent elements within interfaces, all contingent elements will be ignored if an interface contains another interface.
    • Oneline Diagrams: Option to Convert MS-Lines to Background Lines has been removed from the right-click menu for multi-section lines on a Bus View and Substation View.
    • Power Flow Solution: Fixed an error with the VSC DC Line solution when regulating the MW on the FROM side DC converter AND when regulating the DC MW flow instead of the AC MW. Changes were made in the November 20, 2020 patch that allowed support for Rdc=0 in the calculation, but this introduced this bug.
    • Transient Stability: Fixed access violation caused when using the Show Transient Stability RAS Validation Info option on a Remedial Actions or Remedial Action Elements case information display that is empty.
    • Transient Stability: Fixed OEL2C to match GE dyd file order.
    • Transient Stability: Fixed the numbers of parameters for REEC_D to match PSLF dyd file. There was an error before in the parameters when writing from pwb to dyd file.
    • Transient Stability: When auto inserting relays fixed a bug in which the shape was set to -1. This was causing the relay to not operate correctly because it was disabling the relay.
    • Transient Stability: The default value of all InternalAngle parameter in Zones 1-4 of DistRelayITR is now changed to 90 degrees.
    • Transient Stability: The description for impedance-related parameters of DistRelayITR is now corrected to show them as a percentage of the line parameters.
    • User Interface Dialogs: Updated captions for Geo Data View objects shown in the Display Explorer.

December 8, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): The TapTransmissionLine script command has a new parameter added to the end of the command called ReplaceObjects. Default is NO. When set to YES the original line object will be replaced with the tapped line objects on all open oneline diagrams.
  • Auxiliary Files (SCRIPT and DATA Sections): A script command has been added to allow clearing a single fault that has been calculated with the fault script command. The new command is simply "ClearFault", with no parameters needed.
  • User Interface Dialogs: Added an option to the Auto Tap Transmission Line dialog to allow the user to choose to replace the original line object with the tapped line objects on all open oneline diagrams. If this dialog is opened by right clicking on a line object in a oneline, the line object that is clicked will always be replaced with tapped line segment objects regardless of how the option is set in the dialog.
  • Bug Fixes

    • Oneline Diagrams: Fixed bug with saving onelines in jpg or gif formats in which only part of the display would be saved.
    • Optimal Power Flow (OPF): Modified the piece-wise linear cost function so that it will always show extra decimals places in order to show at least 6 significant digits. Previously it always showed 2 decimal places, so that a cost of 0.765432 would appear as 0.77. Now will add decimal places to get to 6 significant digits.
    • Sensitivity Calculations: Fixed bug that indicated that elements were in different islands when calculating TLRs on interfaces that included other interfaces even when all elements were in the same island.
    • Transient Stability: Modified the WTGWGO_A model so that when the voltage drops below Vwgo it automatically restarts the playback of the Pref signal regardless of whether a voltage drop and Pref recovery playback had already begun.
    • Transient Stability: Transient Plot definitions which showed results for transformer fields where not being read back in from an AUX file correctly. This has been fixed.
    • Transient Stability: In the governor model UHRSG, the Pref input parameter is like a limit on the Pmech output. If "Modify Limits and Run" is selected in Transient Stability Options, then the Pref value is set the same as Pmech, and valve position is set to 1.0.
    • Transient Stability: For excitation limiter OEL4C, Transition Events are now added to the Events log in Transient Stability to show when the model is injecting a non-zero signal into the summation joint of the related Exciter Model. This is useful for extended-duration simulations.

November 20, 2020

Features and Improvements

  • Transient Stability: Adding support for the VSC DC Line dynamic model named VSCDCT.
  • Bug Fixes

    • Case Information Displays: Fixed bug with the fields for NetInjection for Areas and Zones. They were off by a factor of Sbase.

November 13, 2020

Features and Improvements

  • Transient Stability: Added a right click option to a list of multiple transient contingencies to "Set into One Contingency at a Time". This switches the dialog back to the process one contingency at a time and choose the contingency that had been right-clicked on.
  • Bug Fixes

    • Case Information Displays: Fixed bug with contouring of case information displays
    • Contingency Analysis: When loading a Custom Monitor or Transient model contingency violation from an auxiliary file and the violated element could not be found, it was possible that access violations could result when saving a PWB, saving an auxiliary file, or viewing violations in case information displays. This has been fixed.
    • Difference Case Tool: The use of the difference case tools with ReactiveCapability objects was not always working correctly. It worked correctly when opening a case, setting as present case, and then opening a second case. However, when opening a case, setting as present case, and then editing that case the status of ReactiveCapability curve objects as being new or removed was not being handled correctly. ReactiveCapability objects are unique in that if even one entry of the curve is edited, then Simulator will consider the entire curve as a new curve.
    • Distributed Computation: Changed distributed computation so that client processes only use the primary key to identify data. This prevents potential crashes or missing result data due to data from a distributed calculation not being identified sufficiently in order to match it with the model in the main process.
    • File Formats: Modified storing in Matpower format to include DistGen fields.
    • User Interface Dialogs: When opening the VSC DC Line dialog an access violation could occur making it impossible to open that dialog. This has been fixed.
    • User Interface Dialogs: Added the ability to close the following dialogs with the ESC key:
      Area/Zone Filter Dialog, Simulator Options Dialog, Limit Monitoring Dialog, Difference Case, Oneline Options, Default Drawing Values, Custom Hints, Dynamic Formatting, Keyboard Shortcuts, Display/Column Options, Data View Dialog

October 28, 2020

Bug Fixes

  • Oneline Diagrams: Fixed bugs with AutoInsertBuses and AutoInsertSubstations script commands when only specifying the required parameters. If the "filename" was not specified even though it wasn't needed, an error would result that the filename must be specified. This has been fixed.
  • Transient Stability: Fixed a bug that occurred under the following situation.
    1. Fault was applied on a Branch that was a transformer
    2. Transformer did not have any magnetizing admittance
    3. Fault was applied to the TO end of the transformer (which ever end is defined as the "To" end in the power flow data object)
    4. Transformer was Opened only at the FROM end of the transformer
    If all these situations were met, then the fault admittance would continue to be included at the FROM bus which was not correct. The fault admittance should be applied at the TO end in this situation as that is where the fault was. If there was some magnetizing impedance included then the bug did not occur.

October 27, 2020

Features and Improvements

  • Oneline Diagrams: A blank File or Action can now be specified with the Oneline Link object to indicate that the Saved View should be applied to the oneline that contains the link
  • Transient Stability: Added ability for a TSResultEvent object to show the custom fields for the object to which the result event refers. Under the folder Object Fields\Custom, there will be 5 custom integer, 5 custom floating points, 5 custom strings, and the memo field. In addition we have exposed under the folder Custom, the Custom Expressions, Custom Strings Expressions, and Selected field for the TSResultEvent itself.
  • Bug Fixes

    • PV and QV Curve (PVQV) Tool: Corrected label on the PV dialog when setting High Voltage Level to Consider Inadequate to "High Voltage Limit Set" instead of "Low Voltage Limit Set".
    • Transient Stability: Modifying how reactive current injections for the REGC_A and other current injection models are handled in the network boundary equation at very low voltages below 0.40 per unit.

October 16, 2020

Bug Fixes

  • Distributed Computation: Fixed an error that caused distributed computation to fail when using the Result Storage options in contingency analysis.
  • Transient Stability: In converting REEC_A into REECA1 for PTI the Pflag and PQflag were flipped one another. This is corrected in this patch.

October 8, 2020

Features and Improvements

  • Data Checks: Data Check fields were not being correctly displayed for Model Condition, Model Filter, and Model Expression objects. This has been fixed.
  • Bug Fixes

    • Data Checks: Data Check fields were not being correctly displayed for Model Condition, Model Filter, and Model Expression objects. This has been fixed.

October 7, 2020

Features and Improvements

  • Difference Case Tool: Modified the Section field of a Branch to properly show a Section difference treating the Section as an identifying string. Thus if a section changed from 3 to 4 then previously it would have displayed a "1" (because it increased by 1). Now it will show "4|3" instead which is more useful
  • Transient Stability: Modified the CCOMP4 model so that when the user enters Vmax = Vmin = 0.0 then the Vmax/Vmin limits are ignored.
  • User Interface Dialogs: Modified so that the user can control the number of conditions displayed at once on the ModelFilter and Filter dialogs. Previously once more than 4 conditions existed a scroll box would contain them all. Now up and down arrows display to allow this to be changed.
  • Bug Fixes

    • Contingency Analysis: Fixed bug that did not include the Time Delay when implementing SOLUTIONFAIL remedial actions with contingency analysis. If the power flow solution failed, any SOLUTIONFAIL action with a Model Criteria that was met would be implemented at the same time even if they had different Time Delays. Now only the eligible actions with the lowest time delay are implemented at each step of the SOLUTIONFAIL process.
    • Scheduled Actions: Fixed a bug in Scheduled Actions where Scheduled Action objects read in from an AUX file were not properly inserted into the case.
    • Transient Stability: Value being output for Other Field "Zone 4 Signal" for DistRelay and DistRelayITR was incorrect, even though the zone 4 was functioning properly.
    • User Interface Dialogs: Modified the ModelFilter dialog so that when a very large number of ModelCondition and ModelFilter are defined that the dialog does not take so long to open. For cases that had several 1000 of these defined and for a Model filter that had dozens of conditions, the dialog was taking about a minute to open. This has been fixed so that even with 10,000s defines and 100 conditions the dialog performance is good

October 1, 2020

Bug Fixes

  • File Formats: Fixed a bug where line shunts on multi-section lines were not being read from an EPC file when reading it as a new case. This bug was inadvertently introduced in the Sep. 22nd patch with the change that was made to fix reading line shunts when appending an EPC file to an existing case. Multi-section line shunts should now be read and assigned correctly both when reading EPC files as a new case and when appending them to an existing case.
  • Power Flow Solution: When modeling phase shifters as discrete controls, the numerical check in the power flow solution to prevent controller oscillations was not functioning as expected in some rare situations. This has been fixed.

September 28, 2020

Bug Fixes

  • Power Flow Solution: Added code to recalculate contingent interface flows when restoring a power flow state. Previously the contingent interface flows were left unchanged when restoring power system state.

September 25, 2020

Features and Improvements

  • Transient Stability: Change the message for LHFRT relay to be in Hz instead of pu.
  • Bug Fixes

    • File Formats: When appending EPC files to a case, added in more consistent logic to match line shunts record. This also impacts the reading of CTG files which contain line shunt outages.
    • File Formats: When deleting the object associated with the Buyer or Seller of the PTDF calculation, the reference to the object was not removed which could result in an access violation when trying to save the PWB file. This has been fixed.
    • General: Fixed an issue that could cause Simulator to crash primarily when logging in to a machine via remote desktop, though it was also possible at other times when system properties like monitor resolution were changed.
    • Transient Stability: Bug Fix for DistRelay and DistRelayITR. When configured in DUTT scheme (i,e., TrasferType = 1) the Zone 1 communication signal from the Far End was being incorrectly updated by tracking the apparent impedance at the Near End. This has been corrected to track the apparent impedance at the Far End.
    • User Interface Dialogs: Fixed bug with bus dialog in which the Device Info tab is shown as active but it is showing info for the GIC tab.

September 18, 2020

Bug Fixes

  • Oneline Diagrams: Fixed bug with using two color maps with GDVs -- the lower color was not working.
  • Power Flow Solution: When using RunScriptcommand2 in SimAuto to call SolvePowerFlow for a DC power flow solution the errors related to an unsolved DC power flow due to a line with angle differences larger than 360 degrees were not being returned properly. This has been fixed.

September 16, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added new script command: WriteLimitMonitoringSettings
    This command takes 1 parameter, a file name. It saves out the limit monitoring settings.
  • Bug Fixes

    • File Formats: Fixing an issue with writing files that are synced using
      tools like OneDrive, Google Drive Backup & Sync, Syncplicity, etc.
      resulting in corrupted files.
    • Transient Stability: Model improvement for ABBSVC1, the I1 current from the high-voltage bus is now interpreted as the reactive current flowing into the network. Reactive current = QFlowOut / Vmagnitude

September 14, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added a new TS Script command
    TSSetSelectedForTransientReferences(SetWhat, SetHow, [ObjectType List],[ModelType List]);
    Set the Custom Integer field to a corresponding integer or Selected field to Yes/No for objects referenced in a transient stability model with extra objects.
    SetWhat : Either Selected or Custom Integer number (1, 2, 3…). Default is number 1 for the Custom Integer.
    SetHow : when SetWhat = Selected, will be either YES or NO. Otherwise it will be an integer to be used with Custom Integer. Default is 1.
    [ObjectType List] : A comma-delimited list of objecttypes. These are the objects on which the custom field will be set.
    [ModelType List] : A comma-delimited list of transient stability model types on which references will be queried.

September 10, 2020

Bug Fixes

  • Oneline Diagrams: On Geo Data View form the Field Value Option Find button was not linked correctly.
  • Transient Stability: Modified how we write the *.TSR file when saving results from transient stability. Previously it was possible for multiple instances of Simulator to attempt to write to the same TSR file resulting in a corrupted TSR file. This will not longer be possible because transient stability will lock the TSR file for writes which it is running. Other instances of PowerWorld Simulator will be able to read the TSR file while it's being created, but they will not be able to write.

September 8, 2020

Features and Improvements

  • Transient Stability: Added a parameter conversion when writing out a CHVDC2 model to a DYD file. The DYD record does not include the Vrate and Irate input parameters that are used in both PowerWorld and also in DYR files. Instead the DYD record always assumes that the Vrate and Irate are calculated in a hard-coded manner from the DC converter records from the power flow data using
    VrateDYD = dcc.vdc_base * dcc.nbridge
    IrateDYD = dcc.i_rate
    In order to make a model that responds the same writing out the DYD record, a conversion is done for several input parameters as follows.
    1. Per unit voltage input parameters V1 and V2 are multiplied Vrate_PowerWorld/Vrate_DYD
    2. Per unit current input parameters Idc_margin_r, Idc_margin_i, Imax1, and Imax2 are multiplied by Irate_PowerWorld/Irate_DYD.
    3. Current gain parameters Kir, Kpr, Kii, Kpi, Kcos, Kref, and Kmax are multiplied by Irate_DYD/Irate_PowerWorld.
    This converts the input parameters to be consistent with the voltage and current bases used in the DYD file.
  • Transient Stability: On the machine model GENQEC, modified the Limit on the multiplication of Kw*Id to +/-0.4 instead of +/-0.25. Also added appropriate limit violation reporting if the initial value is outside of this range.
  • Bug Fixes

    • Transient Stability: DUTT logic for DistRelay and DistRelayITR is updated to correctly allow for transfer trip from its companion relay

September 2, 2020

Bug Fixes

  • Transient Stability: Modified many of the recent exciter and OEL and UEL models for the IEEE 421.5-2016 standard so that they use the parameter SW1 with a value of 1=Position A and 2=Position B
  • Transient Stability: Added fixes to the Exciter Model AC11C to properly enforce the non-windup limits on the special PID blocks.

September 1, 2020

Bug Fixes

  • Case Information Displays: Fixed some potential access violations that could occur when opening the local menu in a case information display or when attempting to copy/paste data to/from the clipboard.
  • File Formats: Fixed a "List index out of bounds" error that could occur when reading a case that contains unlinked interface elements. This was related to the patch update from August 25 and unlinked interface elements.

August 31, 2020

Features and Improvements

  • Transient Stability: Added more descriptive messages to Transient Events for LHVRT, LHFRT, LHSRT models configured to be in Alarm Mode. They will now show the MW of the generator from the initial condition to provide information about how much generation would have tripped if the model was not in alarm mode
  • Transient Stability: Added a new field that can be added as a column to the Transient Stability Events for "MVA Base". This field will show the generator MVA Base, load MVA, Branch Limit MVA Normal, and Switched Shunt maximum Mvar value. Events for other object types will return a blank.
  • Bug Fixes

    • Contingency Analysis: When reporting disconnected buses as violations, Simulator was using the options regarding ignoring radial buses for limit checking. The ignore radial checking was added for low and high bus voltage violations, but it is not appropriate to ignore radial buses when flagging disconnected buses. Simulator will now report these radial buses as disconnected.
    • Oneline Diagrams: Fixed bug with GDV mosaic transitioning -- it could hang when the Animation Frames was set to zero. Also, now on the transition is using the minimum of either the total time or the total frames.

August 25, 2020

Features and Improvements

  • Case Information Displays: Added secondary filter classes to the TTransferLimiter object. A user was requesting to filter the transfer limiters by bus.
  • Bug Fixes

    • Case Information Displays: When relinking unlinked interface elements, access violations could result when viewing elements in the case information displays that show specific types of elements and the linking was successful. This has been fixed.
    • File Formats: Corrected placement of line shunts when appending an EPC file to a case that already has multi-section lines created.
    • GIC: Added the ability to delete duplicate bd3 file points when loading new files.
    • Simulator Automation Server (SimAuto): Fixing the Register SimAuto and Distributed Computation Configuration utilities to work with the updates made to SimAuto recently.
    • Transient Stability: When specifying Model Plane fields in the Store to RAM Options for transient stability and saving these to an auxiliary file, the variablenames were not being read correctly when loading the auxiliary file. This has been fixed.

August 21, 2020

Features and Improvements

  • Contingency Analysis Tool: Added branch field called Status Change Order. This field can be used during contingency analysis with conditional actions to check the order in which branches changed status. The order is dependent on the contingency element Status group (CHECK, TOPOLOGYCHECK, POSTCHECK, etc.) in which the action is applied. This value is 0 by default, which indicates that a branch did not change status during a contingency. Branches that change status during the same group will have the same order value. Once a contingency has finished processing this field will be reset to the default of 0 for all branches.
  • Transient Stability: Modified the electrical control models for renewable plants named REEC_A, REEC_B, REEC_C, and REEC_D models so that they obey the Transient Governor Response flag that indicates either Down Only or Fixed.
  • Transient Stability: Modified the plant controller model REPC_A model to obey the Governor Response Flag that indicates either Down Only or Fixed.
  • Transient Stability: Added Vemin to Exciter AC1C, AC6C, AC10C and AC11C. Also added VFEmax to AC1C.
  • Bug Fixes

    • Case Information Displays: Entering a blank owner number should have been interpreted as removing that part of ownership, but Simulator was instead just ignoring the input of blank and leaving the existing ownership alone. This has been fixed.
    • Transient Stability: Modified REGC_A, REGC_B, and REGC_C so that Iqrmin and Iqrmax are both ignored if the initial Mvar output of the generator is less than 1% of the MVA rating of the machine.
    • Transient Stability: Corrected ABBSVC1 model's initialization of state T1 and derivative of state T8.
    • Transient Stability: Fixed error with loading the h6e model from a DYD file. It was incorrectly treating it as an unsupported model in PSLF and skipping the model.
    • Transient Stability: Fixed divide by zero error in initializing the DC line dynamic models CDCMC and CHVDC2 if the DC line was out of service in the power flow case.
    • Transient Stability: Fixed a bug with LHVRT relay model that was producing multiple messages when the relay was activated.

August 18, 2020

Bug Fixes

  • Contingency Analysis: Custom monitors should not be included when running contingencies for PV, QV, ATC, or SCOPF. At some point a check preventing this was removed and they may have been included in error. This would have only impacted the modeling of cascading outages with custom monitors.
  • Transient Stability: Fixed an access violation error that would occur with an SVSMO2 model if that switched shunt record had exactly one block instead of more than one.

August 17, 2020

Bug Fixes

  • Transient Stability: Enhanced the code that checks for identical TSContingencyElement actions for area-to-area transaction used with AGC in transient stability. This was not correctly catching some area-to-area transactions. In particular, a transaction at Time A from Area B to Area C was being considered identical to one at Time A from Area B to Area D.

August 14, 2020

Features and Improvements

  • Case Information Displays: Injection groups can now be filtered using advanced filters defined for the PartPoint object type.
  • Case Information Displays: Remedial Actions can now be filtered using advanced filters defined for for Remedial Action Elements.
  • Case Information Displays: Changed searching in the Model Explorer to allow pattern matching when the "Find entire cells only" option is selected. Also changed searching in chooser dialogs so that if a wildcard is used within the search string, searching will still find partial matches.
  • Oneline Diagrams: Modified the GDV style so the GDVs object display lines can show any type of field value for the object. Previously they were restricted to just numeric values.
  • Transient Stability: Added ability to read the CHVDC2U1 model from a DYR file. Modified the treatment of calculation of the Vrate and Irate when loading the CHVDC2 from a DYD file.
  • Transient Stability: Modified the CHVDC2 two-terminal dc line dynamics model and how it enforces minimum size of various time-constants. When any of the following time-constants are smaller than 0.03*TimeStep you will see validation information about how the time-constant are used.
    1. Tr, Tur, Tdr, Tui, Tdi, Tmax and Tref that are smaller than 0.03*TimeStep will be simulated as though they are equal to 0.0
    2. Tvd, Tram, Talpr and Talpi that are smaller than 0.03*TimeStep will be simulated as though they are equal to 0.03*TimeStep
  • Transient Stability: Modified the REEC_D model so that it uses the GovernorResponseLimits flag to modify the Pmax/Pmin values
  • Bug Fixes

    • Contingency Analysis: The definition dialog for Remedial Actions would not always show the correct options. This was dependent upon the location from which the dialog was opened. This has been fixed.
    • Difference Case Tool: Fixed the display of MSLine and 3WX identifier fields in Lines, Buses, and LineShunts, which were not correctly displaying in Base Case elements.
    • File Formats: Fixed a bug where Simulator would not read the comment at the end of a record in version 33 and earlier RAW files if the record ended with a comma before the comment character. We also cleaned up the representation of the comment in the Memo field for all RAW versions.
    • File Formats: Modified the reading of the Margin parameter for a two-terminal DC line when loading from an EPC file so that it gets the margin from the inverter rectifier.
    • Oneline Diagrams: Fixed bug in which copying GDV object records to the clipboard could cause an error.
    • Transient Stability: Fixed bug in CHVDC2 with the timer associated with the Rectifier Angle Minimum Limiter (RAML). Previously the RAML would become inactive Ttram seconds AFTER the voltage went back above Vram. The timer will now expire Ttram seconds after the voltage first drops below Vram. Thus the RAML will become inactive immediately after the voltage goes above Vram AND that timer has expired.
    • Transient Stability: Small numerical modification to how the firing angles are updated for a multi-terminal DC line when including the dynamics of the RL DC line circuits.
    • Transient Stability: Modified the simulation of the CHVDC2 model converter equations for large values of firing angle (above 60 degrees).

August 4, 2020

Features and Improvements

  • Simulator Automation Server (SimAuto): Added RunScriptCommand2(). RunScriptCommand2() is a more usable version of RunScriptCommand() that returns a boolean for success or failure and an status string that contains information about what just happened (an error message, warning, etc.).
  • Simulator Automation Server (SimAuto): Added a SimAuto property called ProgramInformation. ProgramInformation provides version, addon and currently running SimAuto executable in an array of arrays. The first dimension selects the record desired and the second dimension chooses fields from the record. Each record starts with an identifier (currently "version", "addons", or "executable") in the first field, followed by all of the fields containing data for that kind of information.
  • Transient Stability: When saving transient stability results to a CSV file using formats available in the TSGetResults script command add a new option for "INTEGRATED". This will store the results in a single file with a header integrated into the file listing the fields as several rows at the top of the file with information denoting values stored in each column. This is available in the script command as well as on the Plot Designer tab of the transient stability tab under the "Save Selected Plot Data" button.

August 3, 2020

Bug Fixes

  • GIC: Fixed bugs associated with reading multiple b3D files. Also, the B3D file load is now much faster.
  • Transient Stability: When checking the Online field for branches, gens, loads, line shunts, and switched shunts as part of remedial actions used with transient stability, Derived Online was being checked instead. Online is a Yes/No field and Derived Online is a Closed/Open field. This has been fixed.

July 31, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added an Option (Insert Selected Objects Only) to only auto insert buses and substations that are selected (SELECTED = YES).
  • Bug Fixes

    • File Formats: When reading an EPC file generator turbine types of 32 - photovoltaic (fixed) and 33 - photovoltaic (tracking) were switched. 32 was being interpreted as P4 (Photovoltaic, Tracking) and 33 as P3 (Photovoltaic, Fixed) in Simulator. This has been fixed.
    • General: Fixed bug that would not apply an AXD to the currently focused oneline when using a keyboard shortcut.
    • Transient Stability: Fixed access violation in the RSPDC3 DC line transient model added in pervious patch when no link to another DC pole was included. This should not be required.
    • Transient Stability: Fixed error in CHAAUT which was added in the previous patch.

July 28, 2020

Features and Improvements

  • Available Transfer Capability (ATC) Tool: When using the dark color options for case information displays the Normal Field color is white. This is difficult to see in the Multiple Scenario ATC Results grid when the results are highlighted by one of the colors used with iterated ATC methods. Now if the Normal Field color is the default for the dark color options, the font color will be adjusted automatically so that it is more easily read
  • Fault Analysis: A new script command has been added to run the multiple fault calculation, as defined in the fault analysis dialog. The faults to be run must have been previously defined and loaded into the system before the script command can be used.
    The command syntax is: MultipleFault(UseDummyBus);
    The parameter UseDummyBus simulates the check box on the fault analysis dialog for indicating if dummy buses should be created and inserted at the specified percent location for branch faults. If you pass YES, Simulator will insert the dummy buses for each branch fault at the specified location and solve the fault. If you pass NO, then Simulator will calculate the fault at the branch terminal bus that is closest to the specified location. A new column has also been added to the multiple fault results table to indicate if the location of branch faults occurred at the specified percent location, or at one of the two terminal buses of the branch.
  • Oneline Diagrams: Add GeodataviewStyle field to allow "area" scaling to proportionally scale the dimensions (like size) rather than their product (area). This is needed for 1D object like arrows
  • Transient Stability: Modified the cross compound unit governor model CRCMGV to support AGC Control interaction. CRMGV is unique because it has 2 Pref intputs.
  • Transient Stability: Added support for several new DC line transient stability models used within the Eastern Interconnection in North America. These models include: CHATGY, RSPDC3, CHIGATT, CMDWS2T, CEEL2T, CDCMC
  • Transient Stability: Also added support for several DC transmission auxiliary stability models for the same purpose
    CHAAUT, PAUX1T, PAUX2T, PAUX12T, FCWDPT, CFCAUT, SQBAUT
  • Bug Fixes

    • Case Information Displays: Fixed error where the Quick Filter was not available for grids that had been customized after loading a PWB file.
    • Difference Case Tool: When saving removed elements to an EPC file when using the difference case tool, three-winding transformers were not included. This has been fixed.
    • File Formats: When reading distributed generation fields stored with loads in RAW version 34 files, the values for distributed generation MW and MVAR were being read an multiplied by the System MVA base (normally 100). This has been fixed.
    • File Formats: When loading an EPC or RAW file it was possible for transformers with impedance correction tables to be assigned the wrong impedance in the YBus. This could result in incorrect flows on these transformers. This has been fixed.

July 23, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): The CalculateLODFScreening script command now has an optional 17th parameter called CustomFieldOrigCTGName. This is an integer indicating which Custom String field for a processed branch will store the name of the original contingency from which the branch originated. Default is 0.
  • Contingency Analysis Tool: The Summary table on the LODF Screening dialog now shows the "Original Contingency Name" field. If processing lines based on Defined Contingencies, this field will show the name of the contingency from which the single line outage originated. Otherwise this field will be blank.
  • Contingency Analysis Tool: There is now an option on the LODF Screening dialog to populate a custom string field for the branch associated with the Contingency Line in the summary dialog with the "Original Contingency Name" field.
  • Time Step Simulation: Changed the way the status change count works so that status changes from the time step tool are counted.
    I also added a script command to clear the counter.
  • Bug Fixes

    • GIC: Fixed GMD 3D field bug when a B3D file is loaded if the user wants the time-varying fields updated.
    • GIC: Fixed bug in which a few GIC form fields were not getting updated when the form was refreshed. This could cause an issue when say a power flow solution is restored.

July 22, 2020

Features and Improvements

  • File Formats: Added the ability to write into dyr file the REPC_B into a PLNTBU1 and the respective REAX4BU1 or REAX3BU1 models for the Control devices.
  • Transient Stability: On transient stability plots, a hint appears showing information about the plot series when hovering over the plot series trace. This has been modified to also show information about the value and time at the point on the series that is closest to where the mouse is hovering.
  • Bug Fixes

    • Case Information Displays: On a case information display, when doing a flood fill with a cell showing color a confirmation dialog would appear asking if you would like to change color value shown, but the color shown was always gray. Clicking yes would work correctly and change to the color you had chosen, but the gray color on the confirmation dialog was wrong. This has been fixed.

July 21, 2020

Features and Improvements

  • Transient Stability: Distribution Equivalent Models can now be made "Active" or "Not Active", depending on whether to include or exclude from a transient simulation. When they are set to "Not Active", then they are not used and a paricular load model will move up the object hierarchy to find an active Dist Equiv Model. For instance, if LoadModelGroups were assigned to a Dist Equiv as well as assigning a Dist Equiv model to areas. If a load's LoadModelGroup had a Dist Equiv set Not Active, then it would move up to the Area Dist Equiv model instead.
  • Transient Stability: "Show/Save Selected Plot Data" in the Transient Stability > Plots tab, now allows exporting time-series data from multiple plots in the formats available. This applies to all the export file formats.
  • User Interface Dialogs: Changed the default maximum number of line in message logs in Simulator to 50,000 to ensure logs don't remove log messages without the user expecting that.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Reading an AUX file that specified a new BlinkInterval for the Sim_Environment_Options was not working and the value was being left at it's present value. This has been fixed.
    • Case Information Displays: For linear contingency analysis, dc contingency analysis, or ATC analysis, lines whose terminal buses become disconnected during a contingency should not be included as valid monitored lines. This has been fixed. For interfaces, any lines in the interface that become disconnected because their terminal buses are disconnected will now be excluded when determining the post-contingency flow and OTDF for an interface.
    • Case Information Displays: The "Evaluate in Transient" and "Tfilt" fields for Model Expression variables are now included in the Model Expression case information display by default. These fields are also included when creating a default AUX Export Format Description for Model Expressions and saving contingency information using the Save button on the bottom of the contingency analysis dialog and CTGWriteResultsAndOptions and CTGWriteAllOptions script commands. These fields are only used when translating Remedial Actions into Transient Stability.
    • Transient Stability: Fixed a bug with WSHYGP when fR is zero which would correspond to constant speed control (highly unusual setting). This was causing an error and causing Simualtor to crash. This has been fixed.
    • Transient Stability: Fixing some errors with transient stability AGC models when a generator is operating outside of it's Pmax and Pmin levels.
    • User Interface Dialogs: Fixed a bug that could cause an "Invalid operation in GDI+ (Code:11)" error.

July 16, 2020

Features and Improvements

  • General: Added a new field name StatusChangeCount to a Branch object. This field is initialized to zero when a case is first opened in Simulator, or when a branch is first created. After that, every time the status is changed the count will increment by one.
  • Bug Fixes

    • GIC: When reading the GIC NOAA JSON and DAT files the Ex and Ey values were be incorrectly interpretted as East,North. Now they are North,East.

July 14, 2020

Bug Fixes

  • GIC: Fixing bugs associated with loading multiple JSON or NOAA Dat files.
  • GIC: Minor change to update the GIC 3D field time point date/time fields to local or UTC when the use local timezone box ix checked.
  • Oneline Diagrams: Fixed an issue with InsertedConnectedBuses. Now will work with InsertedConnectedBuses("DisplayBus 1234");

July 10, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Recently an option was added when reading PTI RAW files to allow the user to specify how to handle duplicates of devices in the RAW data; to keep only the last entry of each duplicate device, or to keep all duplicate devices by dynamically updating the IDs of each to make them all unique in the load flow data. This option was previously only available through the user interface when choosing to open a RAW file with options. Now the option has also been added to the OpenCase script command in the option set that applies to PTI file types. The option was added as a third parameter in the PTI option set, and is named HowToKeepDuplicates. The two options you can set are LAST or ALL, which correspond to keeping only the last duplicate of each device, or to keep all duplicates of each device and make them unique.
  • Bug Fixes

    • General: When pasting buses with the create new object option, a new bus is created that is higher than the highest bus number in the case. This wasn't working properly and is now fixed.
    • PV and QV Curve (PVQV) Tool: When running QV analysis on a full topology case, errors and access violations could occur if a contingency or base case did not solve and fake generators were used to try to make them solvable. An access violation could also occur if clicking the Stop button to abort a run. All of these problems have been fixed.

July 9, 2020

Features and Improvements

  • Case Information Displays: Modified the Column Metrics to show more information.
  • File Formats: When writing out an EPC file, no longer check to see if there is a generator with a closed status at a bus to identify it as type 2 or -2.
  • File Formats: When writing out buses to an EPC file and specific voltage ratings for a bus have not been specified, write 1.1 as the default for max ratings and 0.9 for min ratings.
  • Oneline Diagrams: New Oneline Script Command called InsertConnectedBuses that will add connected buses to a display object bus in a online diagram. The input parameter of the script command will be the bus where the user wants to insert the connected buses.
  • Transient Stability: Modified the format for transient stability plot axis numbers so that for values below 100,000 they will continue showing values in the format 30,000 instead of showing 3.0E4.
  • Transient Stability: Added @CTGEVENTSUSER keyword that can be used in transient stability plot title block to display the transient events that are user defined, i.e. the Transient Contingency Elements. Events with other event levels will not be displayed.
  • Transient Stability: DER_A model is now read from a dyd file
  • User Interface Dialogs: Modified the Keyboard Shortcuts features so that they can load AXD files into the presently active oneline
  • Bug Fixes

    • Case Information Displays: For case information display columns shown an color entry, the ability to flood fill the color using the small rectangle in the bottom left of the cell was not working. This has been fixed.
    • Contingency Analysis: The option found on contingency violation case information menus to Create Contingent Interface for Selection was disabled even for some allowed contingency actions. This has been fixed.
    • Difference Case Tool: When writing an auxiliary file with Difference Case added objects, new star buses of three-winding transformers were not being written. This has been fixed.
    • GIC: Fixed issues associated with loadiing JSON electric field data files. Also added ability to automatically update the time-series data when the files are loaded.
    • Oneline Diagrams: Fixed bug when pasting objects with the option to create new model objects. If prompted, the user selected option was working.
    • Transient Stability: Fixed initialization of the H6E governor integrator state when Fd<>0 and Kp<>0.
    • Transient Stability: Modified transient plots so that the format of the label text for horizontal axis and vertical axis labels do not appear with scientific notation if the actual range of the values is very narrow. Previously it was basing the label format only on the values.

June 29, 2020

Features and Improvements

  • Transient Stability: Modified the Generic Limit Monitor using an Mho Distance calculation so that it trips both ends of a line if tripping is requested.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): On the AUX Export Format dialog when using the option to Create Format for Complete Case and choosing the Model Info objects, the ModelResultOverride object type is now included.
    • Transient Stability: Changed the DC4B exciter so its auto setting of Ke when it is zero always uses the PSSE approach since this is a PSSE only model. This change really only affects simulations with a mixture of PSLF and PSSE models such as when building cases that span the Western and Eastern system in the United States.

June 26, 2020

Bug Fixes

  • Oneline Diagrams: Fixed a bug where the labels from a copied object are moved to the new object when pasted. This would remove the label from the old object when copying objects via the oneline diagram.

June 25, 2020

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed access violation when saving case as AUX file. In Retrever, saving a case as an AUX file would result in an access violation while attempting to save objects related to the ATC. This has been fixed.
  • General: Fixed stack overflow error that could occur when using a network cut to set the selected field, select buses for creating an equivalent, or select buses to scale. When setting the number of tiers greater than 0, the selected buses may not have always been correct. This has also been fixed.
  • Oneline Diagrams: An access violation would occur when the "Show Objects That are not In Oneline form" was open but the oneline it was referencing was closed. This has been fixed.
  • Transient Stability: Fixed an initialization bug when the H6E governor model was on a load control mode (because the parameter Fd <> 0) and there was an error that was setting the input to Kp to be non zero and that was creating that the derivative of the velocity (State 5) to be non-zero during initialization.

June 19, 2020

Bug Fixes

  • File Formats: When reading a PTI RAW file it was possible for line ratings to be wrong by a factor of 100. This has been fixed.
  • Transient Stability: Added ModelTransition event to the event log in transient stability when Fast Valving is engaged for either a TGOV2 or TGOV3 governor model. Previously it engaged but no event was recorded making it difficult for the user to notice this was occurring.

June 18, 2020

Features and Improvements

  • Transient Stability: Added a new feature when saving plot images to file automatically from within the transient stability tool. Previously when increasing the resolution to large values that look good in an image or document, the text would become smaller as you increased the resolution of the image. This could be overcome by changing all the fonts sizes but this is very cumbersome. To fix this you may now instead simply apply a scalar number which applies to all text on the image. This if you make an image about 3 times larger than your screen, just set the scalar to 3.0 and all fonts are appropriately scaled.
  • Transient Stability: Made minor modifications to the look of a plot image. Gridlines and tick marks on axes were previously 2 pixels wide and are now 1 pixel instead. There was a drop-shadow around the legend which has been removed.
  • Transient Stability: Redesigned the Auto-Insert Distance Relay Form, and added the capability to specify "Breaker Operating Time" and "Zone 1 Operating Time"
  • Transient Stability: When using a Horizontal Axis that is NOT Time, if a Title for the axis is left blank we now automatically add a title showing the object and field being shown on that axis. This makes it easier to see what the axis is.
  • Bug Fixes

    • Oneline Diagrams: Added some error handling code to prevent problems when trying to open a oneline file in one version of Simulator while a different version of Simulator is the process of writing the same oneline file.
    • Transient Stability: Creating a transient stability plot series for the Model Plane Meets field would not work when loading from an auxiliary file. This has been fixed.
    • Transient Stability: Fixed a nuisance GUI bug with displaying this initial state derivatives for a synchronous machine that uses the H6E governor. That governor was initialized properly but the reported initial Pmech output of the governor was wrong. When the simulation actually began however that was corrected before the first time step so it only impacted the GUI reporting of the initial state derivative of the speed of the machine.
    • Transient Stability: When loading the Voltage Dependent Current Limiter (VDL) curves for the REEC_A, REEC_C, and REEC_D models, Simulator would not allow consecutive points to have the same voltage and omitting the duplicate voltage entry. This meant that a VDL table such as (0,0), (0.9, 0.0), (0.9, 3.0), (2.0, 3.0) which a user was making to indicate that the limit drops from 3.0 per unit down to 0.0 per unit suddenly at exactly 0.9 voltage was not possible. Simulator would end up ignoring the point (0.9, 3.0) because it had the same voltage of 0.9 as the previous point. This has been changed so that consecutive points can now have the same voltage as long as their current is different for this curve.
    • Transient Stability: The new feature for a generic limit monitoring using impedance relays had an error in how the region was defined. This has been fixed.
    • Transient Stability: Modified Captions for Generic Limit Monitors of Apparent Impedance to better explain
    • Transient Stability: Modified all the edit boxes, check boxes, and such on the transient stability dialog so that when an Auxiliary File is opened from anywhere in PowerWorld that this dialog box automatically updates itself to reflect these new settings.

June 16, 2020

Features and Improvements

  • Transient Stability: Added support for generic branch monitor using a simple impedance relay that monitors for the apparent impedance at either end of a branch being within the 100% reach circle of that end of the branch. This feature can be applied to all AC branches in the case or to only those branches that meet a filter.

June 15, 2020

Features and Improvements

  • File Formats: An option has now been added when reading RAW files that allows the user to choose to keep duplicate devices in the RAW file, and change the ID's on those devices so they are all unique. In the past, if duplicate elements existed in the RAW file, only the last duplicate device was kept; all other duplicates of the same device were ignored. In order to take advantage of the new feature to keep duplicate devices, the user must choose to open a RAW file with options. The RAW options dialog will open before reading the file, allowing the user to change the option to keep the duplicate devices and make them unique. Otherwise, Simulator will continue to default to only keep the last duplicate device and ignore the other duplicates of the same device.
  • Transient Stability: Modified to include the AreaName as a default column when looking at transient stability models. Removed the BusName field because the Name_NomKV field is right next to it so it's repetative. Also removed special multi-section line fields from the line relay tables by default.
  • Transient Stability: When plotting Apparent Impedance X vs. App Imp R at one end of an AC branch in the the transient plots, if you had defined any impedance distance relay on that end of the branch Simulator would automatically draw the region boundaries on the plot. This has been modified so that if you do NOT specify any impedance distance on that AC branch then we will now automatically draw the impedance circle 100% of the impedance of the transmission line. This makes it so you do not have to include an impedance relay to get this feature. If you want multiple impedance zones you still need to make the relay model, but if you just want 100% reach it will be automatically drawn.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When adding new interface elements to an interface from an auxiliary file, no element will be created and a warning will be written to the message log if the interface element links to its own interface.
    • Auxiliary Files (SCRIPT and DATA Sections): When reading an auxiliary file and the object type specified in a DATA section header is not recognized, the given object type string is now included as part of the error message.
    • Auxiliary Files (SCRIPT and DATA Sections): Filtering will not be applied to any interface that has a circular reference.
    • Case Information Displays: When adding interface elements to an interface through the GUI, when the element type is selected to be an interface the interface itself will not show up in the list of available interfaces. This doesn't make sense and will prevent various errors associated with circular references.
    • Case Information Displays: Filtering will not be applied to any interface that has a circular reference.
    • Power Flow Solution: Fixed bug that could occur when using the voltage setpoint tolerance in combination with the Generator Remote Mvar sharing that keeps generators within the same relative point in the Mvar. It was possible for generators to get stuck at a limit and not backoff that limit.

June 11, 2020

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): The LoadCSV script command handles file load errors more gracefully.
  • Auxiliary Files (SCRIPT and DATA Sections): When loading Interface or Interface Elements from an auxiliary file, an attempt will be made to relink any unlinked elements when finished loading the respective data section in the auxiliary file. This is mostly intended to link any interfaces that are using other interfaces as elements. Other interface element types may not link correctly, so it is important to check messages in the log that indicate this or check the interface elements themselves to make sure that all are linked.
  • Transient Stability: The new feature for saving plots to PDF files in transient stability the setting of these options in Auxiliary Files and on case information displays was not working properly. This has been fixed.
  • Transient Stability: When adding the new feature adding extra fields to the transient stability results Auxiliary file, accidentally omitted one of the key fields for the contingency name. This resulted in a dialog popping up asking if you wanted to add this field to the result AUX file. This has been corrected.
  • Transient Stability: Modified the ZLINW model which is intended as a broad monitor looking for faults. If a user configured this to actually trip when a fault was detected it would do just that even if the branch detecting the fault has a user specified fault on it. That seems silly. This relay is meant for screening across a large set of lines. This patch modifies the ZLINW model a particular branch will NOT trip if a fault is on itself or on one of its terminal buses.

June 10, 2020

Features and Improvements

  • PV and QV Curve (PVQV) Tool: Added support to save out PV plots into a PDF file -- one PDF file per scenario and/or multiple.
  • Transient Stability: Auto-insert distance distance relay tool now supports inserting either DISTR1 or DistRelay, and also allows specifying whether to Monitor or Trip the line relay.
  • Transient Stability: Added support to save out Transient Stability plots into a PDF file -- one PDF file per contingency. While autosaving plots to a PDF file, a message log has been added if the pdf file is currently open (in a PDF viewer), and hence cannot be accessed by Simulator. When running a Single Contingency in the GUI, a pop-up message has also been added.

June 9, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug in where an Interface Element was Unlinked with a blank entry. It was causing and access violation now it will not cause the access violation anymore.
  • Transient Stability: Added the PUflag parameter to the REPC_A model. When PUFlag = 0 then the input values for PBranch, QBranch, and IBranch to the plant controller are the system MVABase (normally 100). Otherwise if the PUFlag <> 0 then these values are the plant MVABase specified by the parameter mvab.
  • Transient Stability: Added warning messages when reading a DYD file when encountering the syntax mva=123 or mwcap=123 with models for which is this not appropriate and thus these values are ignored.
  • Transient Stability: When loading a DYD file the renewable models names REEC_A, REEC_B, REEC_C, REEC_D, and REPC_A all have as their first parameter a model MVABase named "mvab". For machines and governor models in a DYD there is a syntax of using mva=123 or mwcap=456 before the parameters are specified for the model to specify the base of model per unit system. This syntax is not appropriate for the REEC_* and REPC_* models however, but we are seeing DYD files which have this incorrect syntax. The incorrect syntax for the REEC_* model is as follows
    regc_a 12345 "BusName " 0.32 "G3" : #9 mva=150.0 "lvplsw" 1.00 "rrpwr" 10.0 ...
    reec_a 12345 "BusName " 0.32 "G3" : #9 mva=186.0 "vdip" 0.90 "vup" 1.10 ...
    The correct reec_a syntax for this is
    reec_a 12345 "BusName " 0.32 "G3" : #9 "mvab" 186.0 "vdip" 0.90 "vup" 1.10 ...
    WECC staff checked how this is treated when loading in the native software for DYD files and found that the values of "mvab" were being set equal to the machine model (REGC_*) MVABase when seeing this, which is equivalent to setting a value of mvab to 0.0. PowerWorld will now do the same, though error messages will be written out when encountering this letting the user know.

June 8, 2020

Features and Improvements

  • File Formats: Modified reading of various transient stability ASCII text file formats to process the file looking for illegal characters such as NULL (#0) characters before reading them. These illegal characters are then ignores. This impacts ready the DYD, DYR, MCRE RWM, MTR_LD, GNET, BASEGEN, and IDV files. This had been done for nearly all other 3rd party text file formats, but had not been done for the various transient stability input files until now.
  • Oneline Diagrams: Fixed a bug with Copy/Paste objects and records -- when pasting new records to a Oneline, new branch objects were not correctly linking to the new buses.
  • Transient Stability: Modified event messages when generic limit monitors cause events to occur to make them more clear.
  • Transient Stability: When loading a DYR File that contained only a single DYR record, users sometimes omit the / character that terminates the specification of a single DYR record. Simulator will now automatically assume the end of reading the DYR record if we reach the end of the file without finding a / character. Previously it would terminate and not read that last DYR record.
  • Bug Fixes

    • Transient Stability: When specifying that no Min/Max results should be kept track of, PowerWorld was stilling writing out data to the transient stability result AUX file indicating all blanks for the Min/Max summary information. Now if not Min/Max results have been saved then no records are written.
    • Transient Stability: The default setting for when to engage Fast Valving for the TGOV2 and TGOV3 models is not set to never ("MOD_FastValvingOption"="None").
    • Transient Stability: Added the ability to show more information about the objects related to TSEvents in the results including Bus Names, Nominal kV, Areas, Zones, and Owners. Added these columns to the transient result AUX file to make the AUX file more human readable.

June 4, 2020

Features and Improvements

  • Contingency Analysis Tool: There was a problem when using the distributed contingency analysis where the start and end time were not being set properly. This has been fixed.
  • Transient Stability: When choose to "OPEN NEAR" or "OPEN FAR" TSContingencyElement on a transformer branch, the impedance was not be modelled correctly. This has been fixed.

June 3, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): The file saved using the LogSave script command will now include the time stamp if that option is being used when displaying the Message Log.
  • Available Transfer Capability (ATC) Tool: When using one of the iterated ATC methods, added a line in the ATC analysis log to show the seller and buyer for each limiting pair iterated on.
  • Contingency Analysis Tool: Fixed column headers on "Contingency Constraint Control Sensitivity Dialog".

June 2, 2020

Bug Fixes

  • Transient Stability: Improved the numerical performance of the SVSMO1, SVSMO2, and SVSMO3 to permit large values of integral gains.
  • Transient Stability: Added the ability to link SVSMO3U1, SVSMO3U2, and CSTAT1 USRFCT models to switched shunt dynamic models named SVSMO3 and CSTCNT.

May 29, 2020

Bug Fixes

  • Transient Stability: For the CHSVCT SVC model for switched shunts, when setting Bmax, Bmin, Bfmax, and Bfmin to 0.0, the software automatically determines those values from the power flow data by summing up the available capacitors and basing Bmax and Bfmax on this sum and summing up the reactors to set Bmin and Bfmin. There was a bug that resulted in an error because we were not properly converting this value to per-unit on the SVC MVABase and were instead using the system base. This error has been fixed.
  • Transient Stability: Fixed enforcement of the non-windup limit on the svsmo3 model for the Ki/s state

May 28, 2020

Features and Improvements

  • Case Information Displays: In the menu options for Generator Records on a generator case information display there is an option to "Convert Voltage Setpoint for LDC_RCC" that would only appear if particular fields associated with line drop compensation were the currently selected field. Now this option will appear regardless of the currently selected field.
  • Bug Fixes

    • Oneline Diagrams: Fixed "List index out of bounds" error that could result when using the option on a oneline background object to Show Shapefile Fields.

May 27, 2020

Features and Improvements

  • File Formats: Added support for loading matpower m files with inf or -inf fields for generator q and p max/min fields.
  • File Formats: Fixed issue reading a MatPower case setting the gens to allow AGC if Pmax > Pmin and PG is between them. If a generator is not AGCAble then the max/min values are written as Pg.
  • File Formats: Made changes to Unit Type EPC:
    -Renamed P1 (Photovoltaic, No Storage) into P3 (Photovoltaic, Fixed)
    -Renamed PD (Photovoltaic, DC Coupled) into P4 (Photovoltaic, Tracking)
    -Made FC (Fuel Cells) EPC integer = 48
    -Made SV (Static Var Compensator) EPC integer = 60
    All of this to be in accordance with the WECC 2020 Data Preparation Manual.
  • Oneline Diagrams: Added a button on the GIS Shapefile Data Dialog to "Convert X/Y to Latitude and Longitude". This will convert projected X/Y values that have been specified in the shapefile to degrees latitude and longitude using the WGS 1984 Web Mercator Auxiliary Sphere projection. This is a standard Mercator projection assuming earth radius of 6378137 meters, no flattening, and 0 for the central meridian. This conversion is required before the projection is done to X/Y values in PowerWorld's coordinates. This is an attempt at making shapefiles useful that contain values that have been projected if they have been projected using this particular projection, which seems to be fairly common, but this may not work in all situations.
  • Transient Stability: Modified the InductionMotor3P_A model to include dependence on the source voltage to the terminal bus electrical frequency in per unit.
  • Bug Fixes

    • Transient Stability: Fixed error introduced by attempts to fixed bug related to deleting TSPlotSeries, TSVertAxisGroup, TSSubPlot and TSPlot objects. This new patch introduces access violations caused by the attempted fix in the May 20, 2020 patch.
    • User Interface Dialogs: When showing a list of 2-terminal DC lines in the objects chooser, we were listing each DC line twice with the same string being shown. We have now modified so that one entry lists the rectifier bus first and the second entry lists the inverter first.

May 22, 2020

Features and Improvements

  • Transient Stability: When writing error and warning messages to the log when reading a DYR file, added addition information to show the NAME of buses related to the log messages.
  • Bug Fixes

    • General: Fixed possible access violations that could occur when deleting an object that had been initially assigned to an owner, then removed from that owner, and that owner was then deleted.
    • Transient Stability: When storing transient results to hard-drive, if the check box to use area/zone filters was not checked then all objects would be written to the TSR hard drive file regardless of the the filtering specified with the generator or load objects. Thus the filtering was not being used. This bug did not exist for branches or buses but only loads and generator.
    • Transient Stability: For synchronous machine models, removed the validation warning message that says "Tqop > 5*Tqopp is recommended". This is not a useful warning.

May 21, 2020

Bug Fixes

  • Integrated Topology Processing (ITP): Fixed a bug determining Derived Status and Derived Online. The bug would affect specific topologies where there are no breakers between one terminal of a branch and a radially connected shunt device.

May 20, 2020

Bug Fixes

  • Contingency Analysis: When using the linearized contingency solution methods, disconnected buses were not being reported as violations when requested by the user. This has been fixed.
  • General: Fixed bug that would not allow Owners to be properly updated for generators.
  • General: Fixed bug that would not allow an Owner to be deleted even though it was empty.
  • Integrated Topology Processing (ITP): When using the contingency tool to Convert to Device Contingencies it is now assumed that new energized islands cannot be created due to the actions of a contingency. Previously, the power flow solution option of "Dynamically add/remove slack buses as topology is changed" would be used, but now this option is always assumed false. This means that generators and loads that could form an energized island will now appear as devices in the resulting contingency element conversion.
  • Sensitivity Calculations: Fixed two bugs with the LODF Screening tool.
    (1) When setting the Lines to Process option to use Defined Contingencies, Remedial Action Elements were being included. This doesn't make sense for this tool. These are now ignored.
    (2) When choosing the Lines to Monitor option as Limit Monitoring Settings all lines would be monitored. This has been fixed.
  • Transient Stability: Fixed issue with closing in a synchronous machine in transient stability. This was possible if the bus was connected in the initiation coniditon, but the generator was set to status of OPEN. It is now also possible even if the bus is disconnected initially.
  • User Interface Dialogs: Fixed bug that would not show the correct Unit Type on the generator dialog when opened while in Edit Mode.
  • User Interface Dialogs: The Layers dropdown on the Oneline Ribbon tab was missing and has been added back in.

May 15, 2020

Features and Improvements

  • File Formats: Added options for how to handle duplicate generators read from a RAW file. This includes a choices on the Load RAW with option dialog on how to handle these. The default is to only keep the last duplicate read from the file which is the intended behavior of this format. The alternative the user can choose is to keep all duplicates and have Simulator set unique ID's for each one. Right now this has been added for generators. We plan on rolling this change out to each device type, so that the option will apply to all device sections read from the RAW file. Again, this is not the "correct" treatment of this format, but for some users it is a convenient treatment regardless.
  • Transient Stability: When using the user interface to choose a Horizontal Axis Object for a TSSubPlot, if the sub-plot presently only has 1 vertical axis group which has 1 plot series in it, the object will for the Horizontal Axis Object will now default to the same object as the plot series.
  • Transient Stability: When loading an AUX file that creates new TSContingency objects for transient stability, if the old default contingency named "My Transient Contingency" exists and the old contingency has no elements and no stored results then we will automatically delete the old dummy contingency. Previously it was annoying that the dummy TSContingency named "My Transient Contingency" stuck around.
  • Transient Stability: Modified the Device Type drop down on the Transient Stability Plot Designer so that it always show the entire list without the scrollbar.
  • Transient Stability: When loading a Transient Stability DYR file, if possible we now include the area and zone of the respective device if any warnings or errors string which are written to the message log.
  • Bug Fixes

    • General: In places where a simple string can be used to represent one condition (instead of referring to an advanced filter by name), Simulator was allow the user of the simple string even when the user had defined an advanced filter which used the Area/Zone filters. This has been changed so if you are pre-filtering by the Area/Zone filters then you can not use the simple string representation.
    • Transient Stability: When saving the Transient_Options to an AUX file from the transient stability dialog, we have modified the writing of this AUX file so that it also writes out any advanced filter definitions that are used by the store to hard-drive options.
    • Transient Stability: When deleting a TSPlot, TSSubPlot, TSVertAxisGroup, or TSPlot Series a case information display or from an Auxiliary File script, if the Plot Designer portion of the transient stability dialog was open then it would cause an access violation. This has been fixed.
    • Transient Stability: It was possible to create a duplicate transient contingency element on the dialog for this object. This is now properly not allowed.

May 12, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added CTGProcessRemedialActionsAndDependencies(DoDelete, Filter) script command. See Contingency Analysis section for details.
  • Contingency Analysis Tool:
    Added options is three different places that will allow Remedial Actions and any Model Conditions, Model Filters, Model Expressions, and Model Planes being used by Remedial Actions to be deleted. Model Conditions, Model Filters, Model Expressions, and Model Planes that are being used by other objects or not being used by a Remedial Action will not be deleted.
    These are the three places that options have been added:
    (1) Added "Delete Remedial Actions and Dependencies" option on the Contingency Analysis dialog under Other > Manage Contingency Definitions.
    (2) Added "Delete Remedial Actions and Dependencies" and "Delete Remedial Actions and Dependencies (only selected records)" on the local menu of Remedial Actions case information displays.
    (3) Added CTGProcessRemedialActionsAndDependencies(DoDelete, Filter) script command. If DoDelete is YES, objects will be deleted. If DoDelete is NO, the Selected field will be set to YES instead of deleting objects for all object types described above. Filter is optional, and if not specified or left blank, all Remedial Actions will be deleted or selected along with dependencies. Filter is applied to RemedialAction object type. AREAZONE is not a valid filter option.
  • Oneline Diagrams: Added support for Injection Groups with Geographic Data Views.
  • Transient Stability: Added options to create Transient Stability Contingency Elements for Switched Shunts that allow Set Values To and Change Values By as Percent of Start Nominal Mvar.
  • Transient Stability: Remedial Action Elements for Switched Shunt actions for Set To or Change By in Mvar or Percent are now translated for use in Transient Stability Remedial Actions.
  • Bug Fixes

    • Case Information Displays: On case information displays containing participation points for injection groups, Show Dialog options are now available while in Run Mode.
    • File Formats: When reading a RAW file in the non-transformer branch section, the ownership information for the branches was not being read correctly. This has been fixed.
    • Transient Stability: In Transient Stability validation, eliminated the error check on SVCs to require that the type of SVC be the same in the power flow and transient stability model.
    • Transient Stability: Added numerical checks on the Kvi and Kqi parameters for the REEC_A, REEC_B, REEC_C, and REEC_D electrical models for renewable plants to prevent numerical integration problems when values of Kvi or Kqi are too large.
    • Transient Stability: Modified how the DC line solution transitions between hitting the firing angle limits to improve algebraic network solution.

May 7, 2020

Features and Improvements

  • GIC: Added ability to show DateTime for GIC 3D Time Points.
  • Bug Fixes

    • Fault Analysis: A bug existed where we were trying to use the wrong zero sequence impedance values for Delta - Grounded Wye transformers ONLY when calculating the post-fault branch currents. This has been fixed.
    • Transient Stability: Fixed bug that would not update the Case Information Toolbar to match the correct tab when viewing Validation Errors, Validation Warnings, or Informational Messages on the Validation page of the Transient Stability dialog.

May 6, 2020

Features and Improvements

  • GIC: Added support for GMD JSON files.
  • Transient Stability: Contingency Element options have been added for Switched Shunt actions to Change Values by or Set Values to for specifying changes to Nominal Mvar.
  • Bug Fixes

    • Case Information Displays: Fixing an access violation that can occur when closing some dialogs associated with various case information displays.

May 4, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added ATCWriteAllOptions("filename", AppendFile, KeyField) that saves the same objects as ATCWriteResultsAndOptions but always uses the concise format for object fields and headers and does not save using Subdata. RAS and contingency actions are saved using dependencies.
  • Available Transfer Capability (ATC) Tool: Added option "Use Concise" on the GUI dialog that allows the saving of ATC options and results. This will save using the concise format for object fields and headers and does not save using Subdata. The option will be unchecked by default in Simulator version 21, but will be checked by default in Simulator version 22.
  • Case Information Displays: Added Number of Tie Lines field with Substation objects.
  • GIC: Added new GMD 3D functionality.
  • Bug Fixes

    • File Formats: When writing to RAW files fixed an issue where we were writing out a minimum R value for series capacitors of 1x10-7, but when reading the RAW file back into Simulator, only considering a branch with -x a series capacitor if R = 0. Thus the type assignment of series capacitor was never getting set to branches with -x from a RAW file that we created. To fix this, I first changed the code to write out 0 for R if the value of R was <= 5x10-7. I also changed reading the branches to consider a branch with -x a series capacitor if the abs(R) value is < 5x10-7 instead of = 0.

May 1, 2020

Features and Improvements

  • Oneline Diagrams: Modified contouring to allow contouring of spatial data without explicit oneline objects. This is useful for GIC electric fields.
  • Bug Fixes

    • Case Information Displays: Fixed an "Argument out of range error" that could result when including the Nominal kV Range field in a Substation case information display and there are substations with no buses.
    • Case Information Displays: Fixed an issue with case information toolbars not updating properly when selecting a record in a particular grid.
    • File Formats: Fixed bug in EPC file writing - due to an uninitialized variable, this was transferring lines shunts from the "fromEnd" to the "toEnd" or vice versa. This bug would have only affected line shunts in a multi-section line.
    • File Formats: Fixed error where we were not subtracting distributed generation amounts from load amounts when writing to older versions of RAW files. This would create mismatches and potential solution failures if the user saved to a RAW file version prior to 34.
    • Power Flow Solution: Error checking in Simulator between switched shunt and transformer control was checking that the MIDPOINT of the shunt regulation range was inside the regulation range of the transformer. For example if transformer regulation range was between 1.02-1.03 and the shunt range was 0.95-1.03, then the error check would incorrectly turn off the transformer because the midpoint of the shunt range is 0.99 which is not within the transformer range. This has been fixed by instead ensuring that there is an overlap in the shunt and transformer regulation range.
    • Transient Stability: Fixed enforcement of the current limit on an REGC_B machine model.

April 27, 2020

Features and Improvements

  • Contingency Analysis Tool: When using one of the Linearized Lossless DC Calculation Methods buses that become disconnected can be reported as violation if choosing that option.
  • Oneline Diagrams: Hidden Geographic Data View objects are not contoured.
  • Oneline Diagrams: Added Delaunay Triangulation as a Countour Method with Contour Options.
  • Bug Fixes

    • Contingency Analysis: Fixed a few bugs when using Expressions with the ViolationCTG object type. Access to LimitViol and Contingency expressions are allowed through this object and the various expressions were not always being identified correctly. There is a maximum allowed number of Expressions that can be created for ViolationCTG objects, currently 5, and this was not being enforced.
    • Distributed Computation: Distributed contingency analysis result processing performance has been improved. Long post-run stalls should be much shorter in duration if they still occur.
    • General: When writing an expression for a custom expression or Model Expression, if no function or operator correctly matches all of the parameter types passed into it (whether string, integer or float), Simulator will now give a more verbose error message that lists all of the overloaded functions or operators that match the name of the one used to give the user more information.
    • User Interface Dialogs: Simulator log messages copied to the clipboard will include the timestamp when shown.

April 22, 2020

Features and Improvements

  • General: Added Tap Step Count field with Branch objects to show the total number of tap steps for a transformer.
  • PV and QV Curve (PVQV) Tool: Added options to track loads in Quantities to Track with the PV and QV tools. MW, SMW, IMW, ZMW, Mvar, SMvar, IMvar, and ZMvar can now all be tracked and plotted.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When using the ATCWriteResultsAndOptions script command and when saving ATC results and options from the ATC dialog, Injection Groups that are used for the source and sink and Interfaces that are used with ATC Extra Monitors and multiple scenarios, along with any injection group or interface dependencies, will be saved to the resulting auxiliary file. When saving contingency settings along with the ATC options, dependencies will always be saved now. Previously all Model Conditions, Model Filters, Model Expressions, and other object types that are used to define Remedial Actions were being saved even if they weren't used as part of a Remedial Action. Interfaces and Injection Groups are now included in the dependencies for Remedial Action definitions.
    • Contingency Analysis: When setting up a contingency solution it was possible that a generator that was at it's Max or Min MW limit may appear to be violating it's limit and thus turned off AGC during the contingency solution. This has been fixed.
    • Difference Case Tool: When saving objects to an EPC file from the Difference Case tool or from case information displays, three-winding transformers were not being written. This has been fixed.
    • Model Explorer: Updated Model Explorer folder's object count for OPF Phase Shifters to match actual phase shifters, and not all branches.
    • Transient Stability: Updated the handling of the Bmax limit for SMIB calculations on several exciters.
    • Transient Stability: Fixed some issue with limits being checked during the SMIB calculations. There are now much fewer positive eigenvalues.
    • Transient Stability: An access violation could result if using a transient stability contingency action on a generator to Enable AGC or Disable AGC if the generator had no AGC model assigned. This has been fixed.
    • Transient Stability: Fixed error in REGC_B model with the DQFlag. Value of 0 means Q-priority and non-zero is P-priority. This was backwards.

April 14, 2020

Features and Improvements

  • General: New distributed computation configuration command line tool has been added to aid in scripting the automatic configuration of multiple machines across a network.
  • Transient Stability: Added new CDC1T two-terminal DC line model. This is a stripped down version of the CDC4T model.
  • User Interface Dialogs: Added two new tabs on the Contour Options dialog. Contour Data Points shows the x,y location on the oneline of the object being contoured and the value of the field being countoured along with the color of the countoured value. Contour Pixels provides details about the pixel color and location in the contour.
  • Bug Fixes

    • File Formats: Fixed access violation that could occur when loading DYR file containing SVCs.
    • File Formats: Updated Areva contingency parser to handle injection groups (LDAREA). Previously they were unhandled, which resulted in them being incorrectly treated as line open contingencies (the default). This was causing an access violation when saving the contingency list to file.
    • Simulator Automation Server (SimAuto): Fixed RegSimAuto registration check so it no longer fails when checking to see if the registered SimAuto executable and the local executable are the same files.
    • Transient Stability: Fixed significant error in the loading of PSSE User Defined GENPTJ models. We were treating the Kis field as Ra.
    • User Interface Dialogs: Disable the Area/Zone/Owner filter option on the Area/Zone/Owner filter dialog and the Tielines between Areas case information display. The Area/Zone/Owner filter is not applied here.
    • User Interface Dialogs: Enabled Advanced Filtering for the Area and Zone case information displays on the Limit Monitoring Settings dialog.
    • User Interface Dialogs: Disabled the option to Use Area Zone Filters for case information displays that do not allow Area/Zone/Owner/Data Maintainer filtering. This option wasn't doing anything but this change makes it clearer that it is not applicable.

April 9, 2020

Features and Improvements

  • Transient Stability: When using the Show Dialog option on the Transient Stability Models in Use case information display, a case information display of only a single model type is opened. Delete is now an option on this case information display.
  • Transient Stability: Delete is now an option with the Transient Stability Models in Use case information display. This will allow deleting all models of a particular type.
  • Bug Fixes

    • Contingency Analysis: When auto inserting contingencies and creating combinations of different object types, the maximum number allowed for each object type has increased from 3 to 6.
    • File Formats: Fixed bug in reading Matpower files.
    • File Formats: Fixed bug with loading a PTI DYR file that contained two-terminal DC line dynamic models. This bug was just introduced but is now fixed.
    • General: Fixed a bug that could result in calculating incorrect transformer regulation sensitivities. This would occur when doing the calculation for "Determining the side of transformer on which regulated buses are. This is needed to write to some non-PowerWorld file formats." Sensitivities could end up being calculated as NAN.
    • Power Flow Solution: Fixed access violation error that was showing up during Power Flow calculation. This would occur only when there were Interfaces defined in the case that contained contingencies like branch open/close elements, AND these open/close branches were already open/close in the base case.
    • Transient Stability: Better handling of the Model Instance field that is used with types of dynamics models where more than one of that type can be assigned to the same object.

April 7, 2020

Features and Improvements

  • Transient Stability: Improved support for loading in PSS/E idev files for transient stability.
  • Bug Fixes

    • Distributed Computation: Fixed distributed computation configuration page table alignment.
    • Distributed Computation: Fixed an access violation that could occur when selecting a user in the distributed computation configuration tool.
    • Oneline Diagrams: Fixed a bug displaying the loss field on a diagram depending on which end of the line the field was closest to. If it was closest to the Far bus, it would display the series I^2*R losses instead of the total loss. It should be displaying the total loss always, regardless of how many times displayed or which end of the line it is closest to. The series loss has its own field that should be displayed if the user wants to see the series only losses instead of the total losses.
    • PV and QV Curve (PVQV) Tool: Fixed bug with maximum mismatch information not showing up for critical PV scenarios.
    • Scheduled Actions: Fixed an anchoring issue with the Scheduled Actions dialog.
    • Transient Stability: Saving TS results out to a text file (csv, jsis, etc) was not working when results were in Hard Drive. If Transient Stability was NOT open, then nothing was being saved. If Transient Stability was open, then it would alternate between working okay and not working at all, for consecutive TSGetResults() script command, for example. If Transient Stability dialog was open, and one were to clear the time values from RAM, then it would alternate between working okay and not working at all, for consecutive TSGetResults() script command, for example. This has been fixed.

April 1, 2020

Features and Improvements

  • Transient Stability: Added a new parameter to the ATRRELAY called "LeaveOneOn". Setting this parameter to a non-zero value will force at least one generator to remain online when a tripping command is sent. The generator with the smallest initial MW output will remain on.

March 31, 2020

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): The AutoInsertBuses script command has a couple of fixes. The MapProjection parameter should take "xy" instead of "x,y" as input. The last parameter FileCoordinates, which was intended to indicate if an input file list values in x,y or lon, lat, is redunant due to the MapProjection field and is no longer required. Including this parameter will not cause an error but it will be ignored and shound not be included with new auxiliary files
  • Transient Stability: Fixed a bug in reading a WECC switch file that could result in an access violation.
  • Transient Stability: When a 2 terminal DCline has either the rectifier or inverter AC bus disconnected from the rest of the AC system, then in the steady state power flow the DC line is considered out of service. This is true even if the DC line is set to be on power or current control because obviously it can't be on if the AC system is dead. This worked fine in the steady state power flow, however in the transient stability system if the DC line was set to be on power or current control and the AC system to which it was connected was dead there were errors resulting in undefined power flow mismatches at the terminals of the DC line (even though those terminals were disconnected). This has been fixed.
  • User Interface Dialogs: Closing the Run Mode Line Dialog could take a very long time on large cases. This has been fixed.

March 26, 2020

Bug Fixes

  • GIC: An access violation could result when going from Edit to Run mode after moving the terminals of branches to different buses. This would occur even when not doing a GIC solution. This has been fixed.
  • Power Flow Solution: When generators remotely regulate a bus that can not be reached without crossing buses that have SVCs of type svsmo1 or svsmo3, then it is impossible for these generators to perform remote regulation. This data input error had been captured between generators in the past, but was not being captured for a combination of gens/SVCs. It is now properly captured and an appropriate warning message is written to the log and the generator control is not enforced.
  • PV and QV Curve (PVQV) Tool: Fixed an access violation that could result when running PV analysis. This could result if the step size could not be reduced from the Initial Step Size because the Minimum Step Size is greater than the reduced step size, i.e. (Initial Step Size/reduction factor) < Minimum Step Size.
  • Simulator Automation Server (SimAuto): Bug fix in error message management -- message indicating that required fields were missing when attempting to add a new object through SimAuto was being overwritten by a generic "Object not found".
  • Transient Stability: Added three changes to help with solving MMWG transient stability cases: 1) check on GENTPF/J XL <= xdpp, 2) check on ST6B exciter Tda small, 3) added subinterval to handle large negative eigenvalues on AC7B when Kpa*Kf1*inv(Te) is high.
  • Transient Stability: Added initial limit adjustment of the temperature limit value for the GAST2A and GASTWD turbines.
  • Transient Stability: ST6B correction of low Tda values.
  • Transient Stability: For the REPC_B model if a user does not specify any Control Device to which the output is connected, Simulator will assume that Control Device 1 is the generator to which the REPC_B model is assigned.
  • Transient Stability: Fixed initialization of Pmech for HYGOVR and IEEEG3 governor models.
  • Transient Stability: Modified the REEC_A, REEC_B, REEC_C, and REEC_D models. We will now consider the following as an initial limit violation: the Vref0 input parameter creates an initialization that results in the output of the deadband dbd1/dbd2 being non-zero. If auto-correcting initial limit violations, then the value of Vref0 will be modified to either Vinit+dbd1 or Vinit+dbd2 so that the output is at the edge of the deadband.
  • Transient Stability: Modified all machine models that use the Lvpnt1 and Lvpnt0 "low voltage power management" block that manages the current source interface to the network equations. When the Lvpnt1 input parameter is higher than the initial terminal voltage then this is now treated as initial limit violation and we always automatically decrease Lvpnt1 to be equal to the initial terminal voltage. This effects models such as WT3G, WT4G, PV1G, PVD1, REGC_A. This low voltage block should never been active in the initial condition.
  • Transient Stability: When Ke=0 for some types of Exciter models, the value of Ke is automatically calculated based on the initial Field Voltage to achieve a particular value of Vr. This automated routine is handle differently in different software tools and PowerWorld has an option called "Exciter Automatic Parameters" which is set appropriate depending on whether you have loaded a DYR or DYD file. In cases where folks merge two data sets from two different software tools however this option may be more nuanced. This patch modifies this option so that particular Exciter models that are only supported by one other software tool will always use the approach used by that software tool.

March 18, 2020

Bug Fixes

  • Case Information Displays: Fixed possible access violation that could result from changes made in the March 17, 2020 patch to not allow the Quick Filter with case information displays on the Area/Zone/Owner dialog.
  • Oneline Diagrams: Fixed a bug with the display of LineFlow and InterfaceFlow indicators, which were not properly respecting "do not zoom" format settings.

March 17, 2020

Bug Fixes

  • Case Information Displays: Quick Filtering should not be allowed for the case information displays on the Area/Zone/Owner dialog. All objects should be shown at all times. Advanced Filtering had been disabled, but Quick Filtering was still allowed with no way to remove the filter. This has been fixed and Quick Filtering is disabled as well.
  • Power Flow Solution: Fixed a problem with DFACTS regulation. It was reported that DFACTs were not regulating into a negative reactance range when capacitance is available. The problem was that the minimum injection value was incorrectly being limited at 0 because limits were not being updated after inputting the capacitance values. This has been fixed.
  • Sensitivity Calculations: Fixed the column headers for the multiple direction PTDF values. Now, the header is the direction name. Previously, it was Direction Name + "From" + Direction Name, which doesn't make much sense.
  • Sensitivity Calculations: Set processed flag on the direction when calculating multiple direction PTDFs.
  • Transient Stability: Fixed error when initializing load with distributed generation that is closed but at an open bus. We were getting a divide by zero error on the zero terminal voltage.
  • Transient Stability: The Summary > Models in Use case information display allows opening a dialog to show all models of a particular type that are currently defined. Fixed an access violation that could occur when closing this dialog.
  • Transient Stability: Fixed divide by zero error with WTGTRQ_A and WTTQA1_PTI models when the power/speed curve points are zero.
  • Transient Stability: Modified ESAC2A model so that the Vfemax value is modified if it is initially out of range.
  • Transient Stability: For WTGTRQ_A and WTTQA1_PTI models fixed interpretation of the Flag variable when determining speed dependency. This was needed to fix an issue in which this model and the WT3E1 model had different speed power curve values.

March 11, 2020

Bug Fixes

  • User Interface Dialogs: On the Injection Group dialog, the scroll buttons and dropdown to change the selected injection group were not working to change the selected injection group. This has been fixed.

March 10, 2020

Features and Improvements

  • User Interface Dialogs: Added the ability to search the Case Description using the Search Bar that can be added to the dialog.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: When using the option to create an interface from a limiting element and contingency, three-winding transformer open and bus open contingencies are now included. A three-winding transformer contingency will add the two-winding transformers as interface contingent elements, and a bus contingency will add all branches connected to the bus as contingent elements.
    • Case Information Displays: Fixed a few bugs with the case information display search bar: (1) no longer beep when enter is pressed, (2) no longer clear selected text when enter is pressed, (3) no longer disallow the first entry after hitting enter to conduct a search, and (4) unselect last selection if new search text is not found.
    • Contingency Analysis: When using the option to create an interface from a contingency and violation, three-winding transformer open and bus open contingencies are now included. A three-winding transformer contingency will add the two-winding transformers as interface contingent elements, and a bus contingency will add all branches connected to the bus as contingent elements.
    • Transient Stability: Removed special subinterval integration for GENCLS when using Euler's method on a small case (less than 200 buses).
    • Transient Stability: For the H6E Governor model if the bgvmin is greater than 1 or less than 0 this will be treated as a warning instead of an error.

March 3, 2020

Features and Improvements

  • General:
    Added a lot of new features to the distributed computation configuration tool:
    - Changed the user configuration to allow setting the user to be either
    a user or a security group. Furthermore, this allows selection of
    objects from the local machine or across an enterprise domain forest.
    - Removed the (broken) file permission checkbox.
    - Added a user privilege tester. This checks the user against the system
    limits, configured permissions and also against file permissions for
    pwrworld.exe and simproxy.dll.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When saving injection groups to an auxiliary file with participation points listed in a SUBDATA section and using labels as the key field identifier, blanks would be written instead of the primary key field for participation points where either no label or no label for the bus existed. This has been fixed.
    • File Formats: Fixed a potential bug that would cause reading the RAW file to fail if a branch, switched device, or transformer record was incomplete and stopped somewhere in the middle of the branch ratings. Now Simulator will set defaults for the rest of the ratings and all fields that should have come after the ratings.
    • File Formats: Fixed an issue with switched shunts where the RAW file read would fail if the number of shunt blocks didn't match the number of steps, i.e. the last MVAR block value in the file was missing, so Simulator was reading a value for the number of steps for a block, but the MVAR value of the block was missing at the end of the record. Now Simulator will set that value to 0 if it is missing, and move on.
    • File Formats: Fixed a bug where reading a negative from bus number for branches, switched devices, and transformers would also cause the RAW file read to fail. Since it does not appear that negative from bus numbers are intended or mean anything in the RAW format, I set it to use the absolute value of the from bus number and continue reading the rest of the record as usual.
    • GIC: Fixed retention of the Selected field for GICXFormer objects when switching between Edit and Run Mode.

March 2, 2020

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Changes made in the SendToExcel script command in the January 31, 2020 patch that allow specifying the number of digits and decimal places to use for floating point fields resulted in "format string too long" errors if digits and decimals were not specified and defaults were assumed. This has been fixed.
  • Auxiliary Files (SCRIPT and DATA Sections): When loading Generator fields for BidMW and BidMWhr, then order in which the fields mattered when it should not have. The user was required to load BidMW:5 before loading BidMWhr:5. If they were loaded in the oppositie order then the MWhr values would not be read. This has been fixed so that the order of the fields no longer matters when loading an AUX file, copy/paste or script command.
  • GIC: Fixed bug on gic validation with a full topology model.

February 28, 2020

Features and Improvements

  • Contingency Analysis Tool: Auto Insert options now allow auto inserting single loads.
  • Bug Fixes

    • File Formats: Modified reading a OTG or OTGD file so that the event syntax: "fault 4.0 30.0 30.0 3pb solid", will interpret the second and third strings as the time in cycles after the fault that the from and to end buses are opened on the branch.
    • File Formats: The new feature for having a Voltage Setpoint Tolerance with a generator was not being properly stored to a PWB file. This parameter for VoltSetTol is now stored in the PWB.
    • General: When using the White option for Ribbon Settings, window borders have been increased to make grabbing the border much easier for resizing.
    • General: When filtering gens, loads, and switched shunts by Area, Zone, or Balancing Authority Device or Advanced Filters, use the area, zone, or balancing authority of the shunt object and not the bus. Area/Zone/Owner filtering already did this.
    • General: Added 2 new fields for a Bus: EPCBusType and RAWBusType. Both the RAW and EPC file have an old concept of the user specifying the "equation type" at each bus. In Simulator this is automatically determined from the control devices you have specified in the system, but when writing out to the RAW or EPC file formats Simulator has always written out an integer code appropriate for these formats. These two new fields allow the user to see what these codes in the case information displays.

February 25, 2020

Features and Improvements

  • Transient Stability: Added "Save Plot Images for Auto-Save Options" on the Plot Designer page of the Transient Stability dialog to re-evaluate plots and auto save images after the simulation is complete. It will check for results in RAM and Hard Drive.
  • Bug Fixes

    • Transient Stability: With the Absolute Angle Deviation Generic Limit Monitor, the Rotor Angle Shift will now be used instead of Rotor Angle No Shift when determining if the limit has been exceeded.

February 21, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added LogShow(DoShow) script command to control when message log is shown. When the DoShow parameter is set to YES the message log will be displayed. When DoShow is set to NO the message log will be hidden.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug with script command TSGetResults in which the output csv time is off by one index. Start at the second time step instead of the initial time step of zero. The rest of the values were correct. It happens only when you are reading results from Hard Drive. If the values are on RAM it will give the correct order.
    • Contingency Analysis: When determining if Transient Contingency Elements, Contingency Elements, and Remedial Action Elements are the same as existing elements when pasting from Excel or loading from an auxiliary file, the time will now be checked to the microsecond. Previously a tolerance was being used based on the number of digits to the right of decimal included with the time values. This could end up considering elements the same when they really did not occur at the same time. 9.3 seconds was being treated the same as 9.2502 seconds.
    • Contingency Analysis: Time values with Transient Contingency Elements, Contingency Elements, and Remedial Action elements will always be shown with 6 digits to the right of the decimal.
    • GIC: Fixed GMD bug when there is voltage data and a new line is added.
    • GIC: Fixed code for changing the EMP E3B max value.
    • Time Step Simulation: Fixed issue in time step simulation with how the total area or zone load is assigned to the loads.
    • Transient Stability: When importing relay configuration data in the SEL 421 RDB file format, now recognize identifiers Z1MP-Z4MP in addition to Z1P-Z4P.
    • Transient Stability: While creating transient contingencies from the steady state contingencies list, there was no indication of what the software did. A message box now appears that shows how many transient contingencies were created. Also, the multiple transient contingency grid is refreshed.
    • Transient Stability: When determining if Transient Contingency Elements, Contingency Elements, and Remedial Action Elements are the same as existing elements when pasting from Excel or loading from an auxiliary file, the time will now be checked to the microsecond. Previously a tolerance was being used based on the number of digits to the right of decimal included with the time values. This could end up considering elements the same when they really did not occur at the same time. 9.3 seconds was being treated the same as 9.2502 seconds.
    • Transient Stability: Time values with Transient Contingency Elements, Contingency Elements, and Remedial Action elements will always be shown with 6 digits to the right of the decimal.
    • Transient Stability: Fixed a bug that could produce an out of memory error if storing too many transient stability results to RAM.
    • Transient Stability: Changed Distributed Computing for Transient Stability to use a temporary folder based on the current process ID to prevent clashing if multiple Simulators are running concurrently.

February 13, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added parameter Append to SaveData and SaveDataWithExtra script commands. This is an optional parameter that will be YES by default. Set to YES or NO. If YES and the specified file exists, the file will be appended with the saved data. If NO any existing file will be overwritten.
  • Transient Stability: Added new option to allow a LDTRPMON object to allow you to monitor the entire case.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug with the InterfaceCreate script command that was not doing a case-insensitive check on the specified ObjectType. If 'branch' was entered instead of 'Branch', an interface could be created with interface elements instead of branch elements.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bugs related to identifying display objects by the label of their linked model object in display auxiliary files, pasting from Excel, and display script commands. The Auxiliary ID was not being used to distinguish objects if there was more than one display object for the same model object, and the object with Auxiliary ID = 1 would always be chosen. Display script commands would not allow the use of the linked object label at all. When using labels to identify display objects, the label always refers to the linked model object and not the display object itself. Labels cannot be defined specifically for display objects.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bugs with DoCTGAction script command that would not allow spaces or allowed special characters (such as #) when identifying objects by something other than bus numbers. The brackets are no longer required around the action string, but if omitted the string must be enclosed in double quotes.
    • GIC: Modified so GIC XFormers are not rebuilt when loading aux files/doing scripts just in run mode.
    • Transient Stability: When using the LDTRPMON measurement object, if the area or zone for which summary information was being collected had a CMPLDW which had a non-zero fraction for a Motor D, but zero for the A, B, or C motor, then the the summary information for the Motor D may be shifted up one to the Motor C (or higher). This indexing error in the summary results has been corrected. Note that the input date we have seen from our customers never did this, but it could have.
    • Transient Stability: Fixed the actual values (p of something) of the ldtrpmon. Were reporting the original values.
    • Transient Stability: Cleaned up monitoring of nominal and instantaneous trip values for ldtrpmon monitoring. Also modified throughout to make the values tracked within the contingency summary results to match those in ldtrpmon. There were some strange differences in the treatment of "model trip" versus "relay trip" which have been made consistent between these two situations.
    • Transient Stability: Fixed unusual error that could occur when generating a plot when there is no underlying results to link to.

February 7, 2020

Bug Fixes

  • Case Information Displays: Fixed error with sorting Datetime values on a case information display
  • Transient Stability: Fixed error reading the ldtrpmon object from a DYD file
  • User Interface Dialogs: The Show Dialog for Object option on the Dependency Explorer dialog would not open the dialog for Remedial Actions, Remedial Action Elements, or Contingency Elements. This has been fixed.

February 6, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added script command EstimateVoltages("filtername") that will estimate voltages and angles at specified buses based on voltages and angles at surrounding buses. A valid filter must be specified. An error will result if a blank filter is specified.
  • Transient Stability: Added ability to read the REECCU1 USRMDL from a DYR file and interpret as a new REECC1 model that is idential to the REEC_C model.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed a list index out of bounds error that could result when identifying display objects to create or update through display auxiliary files and display script commands.
    • Transient Stability: Fixed error when reading/writing from/to the DYR file a REECB1 or REECBU1 model. The Tpord and Imax values were flipped when reading/writing them. Thus the treatment inside Simulator had them flipped when reading them.

February 5, 2020

Bug Fixes

  • Case Information Displays: The option to Paste from the clipboard into the SuperArea case information display was not working. This has been enabled for the SuperArea display.
  • Case Information Displays: Fixed access violations when deleting objects from the case information displays found on the Remedial Actions tab on the Options page of the Transient Stability dialog.
  • Transient Stability: Improved numerical properties of the REGC_B machine model hitting the current Imax limit inside the network boundary equation solution.
  • User Interface Dialogs: The AUX file browser was checking for an empty path, but not for paths that don't exist. If it encountered a path that did not exist, it would error out when attempting to build the tree view. A fix has been added to check the existence of a directory before building the tree view.
  • User Interface Dialogs: The Used By list on the Dependency Explorer was limited to 6 levels deep. Now the Maximum Depth parameter that can be set from the Contains list will also be used with the Used By list.

January 31, 2020

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added another default parameter to the DiffFlowWriteCompleteModel script command called IncludeClearPowerFlowSolutionAidValues. By default this is YES. When set to YES the ClearPowerFlowSolutionAidValues script command is included in the auxiliary file saved from the case differences.
  • Difference Case Tool: When saving the Complete Model from the Preset Topological Differences from Base Case dialog, there is now an option to "Include ClearPowerFlowSolutionAidValues Script Command" that is checked by default. When checked this script command is included in the auxiliary file saved from the case differences. This script command was always included prior to this option being added.
  • Difference Case Tool: Modified the following generator fields so they are part of the Difference Case tool comparison: FuelType, FuelTypeCode, FuelTypeInteger, and FuelTypeEPC, UnitTypeInteger, and UnitTypeEPC.
  • File Formats: Added ability to read the H6E governor model from a DYD file. Removed the ability to define H6B and H6BD models from DYD models as those models are obsolete and were never used in any cases PowerWorld had previously seen. The H6E replaced this model.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Allow fields specified with the SendToExcel script command to include user-specified digits and rod.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug reading ATC Extra Monitor records from auxiliary files if the objects are identified by label.
    • Difference Case Tool: When using an AUX Export Format when saving a difference case auxiliary file, the section for renumbering three-winding transformer star buses was being included even if the three-winding transformer object type was not included in the AUX Export Format. This has been fixed so that this section will be excluded if choosing not to include three-winding transformers.
    • General: Fixed a bug where advanced sorting was not properly parsing date-time strings.
    • GIC: Fixed bug in the calculation of the GIC line voltages using a non-uniform field.
    • Transient Stability: Modified plots so that when hovering over the legend entries it doesn't highlight them.

January 27, 2020

Bug Fixes

  • Case Information Displays: Fixed bug in showing super area OPFReferenceObject field in the case information display.
  • Case Information Displays: Contact, Phone, Email, Company, and Location information for a Data Maintainer can now be set back to blank once they have been specified.
  • General: Dynamic Formatting and Data Check objects allow picking Transformer as an Object Type to include in the formatting or checking. This will no longer be allowed. Transformers are just a special kind of Branch and now the Branch object type will need to be used to represent Transformers. Dynamic Formats or Data Checks using the Transformer type will be deleted when loading a PWB or auxiliary file with this type.
  • General: User Defined Case Information displays can no longer be created for Transformer object type. The Branch object type will need to be used instead. When loading a PWB file or auxiliary file, a Transformer User Defined Case Information display will be converted to a Branch type.
  • General: AUX Export Format Descriptions can no longer be specified to save out the Transformer object type. The Branch object type will need to be used instead. When loading a PWB file or auxiliary file with an export format that includes the Transformer object type, this object type will be converted to Branch.

January 23, 2020

Features and Improvements

  • File Formats: Added ability to read a more recent version of the PSLF *.otg format for defining transient stability contingency events.
  • Bug Fixes

    • General: Fixed bug with new option added to Model Plane to extend the inside region beyond a single quadrant. The bug would not correctly identify that the current point was in the region beyond the defined quadrant.

January 20, 2020

Features and Improvements

  • Case Information Displays: Added new fields for Branches to show loading percentages based on Limit Monitoring Settings using Contingency Ratings. These new fields are Used % at From Bus CTG, Used % at To Bus CTG, Used % CTG, Used Limit CTG, and Violated using CTG Limits.
  • General: Added option to Model Plane to choose whether the Inside Region of the plane is contained in the single quadrant in which it is defined or it extends to infinity in the other quadrants. The default is to contain the plane in a single quadrant.
  • User Interface Dialogs: When right-clicking on a generator in a oneline or an area in a case information display there is an option to bring up plots for "All Area Gen IC Curves". This dialog will now contain a legend showing indicating which generators are being shown.
  • Bug Fixes

    • General: Data Check and Dynamic Formatting would not allow the use of secondary filtering. This has been fixed.
    • General: Interfaces could not be filtered by unlinked Interface Elements. This has been fixed.
    • Oneline Diagrams: Fixed a bug causing background objects to display incorrectly when saved to an image file.
    • Transient Stability: Made sure that the Show Block Diagram button is always enabled on the various transient stability object dialogs even when showing the present transient state.
    • Transient Stability: Modified the GICCoreType so that those columns in the case information display are disabled when the GICModelType <> Default.
    • Transient Stability: Changed the default Imarg parameter for EPCDC and CDC6 models so that it is 0.15.
    • Transient Stability: Fixed a bug that when switching from One to Multiple contingencies and vice versa in Transient Stability it was initializing the simulation.
    • Transient Stability: Added "Re-set Min and Max Values" button will only work when the simulation is paused. The values will be re-set to new values only after pressing Continue button in the simulation.

January 13, 2020

Features and Improvements

  • User Interface Dialogs: Modified Island Dialog to 1) allow shifting all the island bus angles by a specified amount of degrees and 2) a list display showing the Island AC tielines (which would obviously be open given that they span two ac islands).
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: An access violation could result when running ATC analysis while using one of the iterated solution methods and using a full topology case while using the option to close breakers to energize switched shunts. This has been fixed.
    • Distributed Computation: Fixed distributed user configuration.

January 3, 2020

Bug Fixes

  • Transient Stability: Greatly improved the network boundary equation solution convergence for events near DC line and Multi-terminal DC line terminals.

January 2, 2020

Features and Improvements

  • Case Information Displays: Added Nominal Tap Ratio field with Branch objects.
  • Transient Stability: Added options to plot and store results for the Meets Criteria field for Model Plane objects in transient stability. This value is reported as 0 for NO and 1 for YES.
  • Transient Stability: Added transient contingency element option that allows the generator delta and delta speed values to be directly changed. The application would mostly be system testing, such as phase angle for generator reclosing.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When creating interface elements through the InterfaceElement object type in an auxiliary file, better error messages will be provided in the log when elements cannot be found in the case.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug in SetSelectedFromNetworkCut script command that reversed the order of the LowerMinkV and LowerMaxkV values. This was reversed even if using the defaults. This would result in branches not being selected.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixing issues to allow AXD support for Model Expression pie charts.
    • File Formats: The ability to add DistMW and DistMvar (distributed generation MW and MVar) to a load record was added in Simulator Version 19. A bug was fixed in Simulator Version 20 on September 18, 2018 related to performing area generation control in areas that contained this distributed generation. For cases in Version 20 and Version 19 created before this change however and then stored to a PWB file, some internal solution variables were stored slightly off. This could cause strange behavior when opening a PWB file stored in version 19 into Simulator 20 and 21. The behavior would result in a bunch of generation moving immediately when solving a power flow. Assuming the inner power flow solution worked Version 20 and 21 would move the generators right back to where they started and from that point on never exhibit this behavior.
    • File Formats: When loading RAS in the Areva hdbexport format the VALID field will now be used for RAS, TRIGCON, GATE, RTRIG, RSTG, and RPACT objects.
    • General: Corrected some bugs with unlinked interface elements that would not correctly identify the original element or allow them to be relinked.
    • Oneline Diagrams: Fixed a bug with the area/zone/substation swapping not working with onelines.
    • Transient Stability: Added the ability to only operate one relay at a time in a load. It follows the same order as before just only added the first or relays found first at any level.

December 17, 2019

Features and Improvements

  • General: Added ability to define "CustomFieldToggleChoice" objects which allow you to define a user-defined list of toggle choices for the CustomSingle, CustomFloat and CustomString fields for object. For toggleable Custom Fields we will only allow them to set the field to one of the choices. Otherwise we set the entry to blank. For custom integers or floats we will set it to the "closest" match. Modified so if custom fields are given toggle choices, then the user may not type in the value on the Custom Tab of various object dialogs. Instead the user must use a drop-down button to choice from among the choices.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): The filename for saving the oneline when using the ExportOneline script command will now support the special keywords starting with @ and the PROMPT functionality.
    • Oneline Diagrams: When auto inserting line pie charts and choosing not to insert pie charts on lines where pie charts already exist, pie charts would not be inserted if Line Flow Objects existed on the lines. This has been fixed so that only line pie charts are considered when adding new pie charts.

December 12, 2019

Features and Improvements

  • General: Added many new FuelType options to the generator field for FuelType. Also added fields for FuelTypeCode (shows only a 2 or 3 character code) and FuelTypeInteger and FuelTypeEPC which show integer versions of these field. The options are taken from the Form EIA-923 annual US Department of Energy filing. The EPC integer codes are taken from the WECC Data Preparation Manual. Also moved the FuelType and UnitType fields into a separate folder named "Type Unit Fuel\" as they were previously stored in the cost folder.
  • Bug Fixes

    • Simulator Automation Server (SimAuto): When clearing all registration type library information wasn't properly being cleared for both 32 bit and 64 bit entries. This has been fixed.
    • Transient Stability: Modified so that special plotting attributes based on a particular TSContingency are only applied to the plot series when creating a plot for multiple contingencies.

December 6, 2019

Features and Improvements

  • Sensitivity Calculations: Modified "Set Sensitivities At Out Of Service Buses To Closest" now enabled to work with Multiple TLR calculations. ETLR and WTLR not recalculated.
  • Transient Stability: Adding a new induction motor model named "InductionMotor3P_A_Beta". Traditionally, detailed induction motor models used in transient stability simulations have not modeled the frequency dependence of the electrical equations. As a result the induction motor model with a constant mechanical torque would return to a new steady state that was a similar constant power instead of scaling with the system frequency. This new InductionMotor3P_A_Beta model will include the frequency dependence.
  • Transient Stability: Added new fields for TSContingency objects to show totals for "Load Relay Tripped" and "Model Tripped" MW Fields.
  • Bug Fixes

    • Transient Stability: The CMPLDW and CMPLDWNF models had hard-coded the Trst field for single-phase air-conditioner models to be 0.4 seconds. This was a mistake as the input data included this value.

December 2, 2019

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added @CASEFILENAME and @CASEFILEPATH as special keywords that will return just the case name without path and extension and just the case path. These can be used anywhere that @CASENAME can be used.
  • Transient Stability: Added the tripping of the LDELEC to the IncrementTotalLoadMWTripped for Load Tripped total in Transient Stability.
  • Transient Stability: For WT3E and WT3E1 models, now modifying IpMax limit on the IpCmd output signal, when there is an initial limit violation.
  • Bug Fixes

    • Contingency Analysis: When using Merit Order Open dispatch on an Injection Group that is part of a contingency action, the amount of injection change might not occur correctly if the injection group contains a combination of generators, loads, and switched shunts. The objects that are not needed for dropping are supposed to be ignored, but this was not being done. This has been fixed.
    • GIC: Corrected GIC bug associated with the pxf.VECGRP_PSSE having a different configuration than what is being used. This could occur if the user changed a configuration. Now the pxf.VECGRP_PSSE is 1) set to blank on a pwb load and 2) set to blank when loaded from a *.gic file. However, the value in the *.gic file is used. Also fixed a bug in which we were not writing out our calculated VECGRP value to a *.gic file, just what had been stored.
    • Simulator Automation Server (SimAuto): SimAuto functions that take a filtername as input would return data even if the filtername that was specified was not valid. This has been fixed. Now an error message will result and no data will be returned.
    • Transient Stability: Fixed potential initialization problem in the CMPLDW and CMPLDWNF models when FmA + FmB + FmC + FmD + Fel = 1.00000 exactly. This could cause simulator to spit out an error indicating that the summation was > 1.0 when actually it was just exactly equal to 1.0.

November 25, 2019

Features and Improvements

  • Case Information Displays: Added three new generator object UnitTypes.
    'P1 (Photovoltaic, No Storage)' (maps to EPC Turbine Type 32)
    'PD (Photovoltaic, DC Coupled)' (maps to EPC Turbine Type 33)
    'P2 (Photovoltaic, DC Coupled No Storage' (maps to EPC Turbine Type 34)
  • Case Information Displays: Added new fields to a VoltageDroopControl object for Pmax and Pmin. These allow the user to monitor a total MW output coming from a group of generators involved in Voltage Droop Control together. Along with these two new user-enterable fields, added several MW fields to the Voltage Droop Control to show MW flows arriving at the regulated bus, MWs coming from generators, and percentages of the new Pmax/Pmin values. Also added percentages of the Qmax/Qmin values too.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When loading an "AUX format export description" from an auxiliary file, if an objecttype was encountered that did not exist it would cause access violations. This has been fixed so that these blocks within the format description are just ignored instead and not read.

November 18, 2019

Bug Fixes

  • Transient Stability: If a fixed switched shunt is assigned to a transient stability model it is allowed to move based on the model. This might require that shunt blocks be defined. Shunt blocks are not always defined for a fixed shunt. During a transient stability run if a fixed shunt has no blocks defined, has a non-zero nominal Mvar output, and zero Min Mvar and Max Mvar, a single block of the initial nominal Mvar output will be created and the limits will be set based on the nominal Mvar output.
  • Transient Stability: Fixed a bug with initializing the GroupMSS transient stability injection group model that could result in switched shunts not moving even though they should based on the enabling criteria and voltage conditions.

November 14, 2019

Features and Improvements

  • Transient Stability: Added validation check on the parameter T1 for IEEEG1 to ensure it is not too small.
  • Transient Stability: Previously for the WT3E and WT3E1 electrical control wind turbine models, setting both Kip AND Kpp would be treated as a validation error. We have modified this to only be an information message indicating that Kip will be treated as a very small positive number instead to allow proper model initialization.
  • User Interface Dialogs: Added the Model Planes to be seen in the Model Filter Visualizations. Also the dialog for model planes will open with a right click on the model plane just as the model conditions do.
  • Bug Fixes

    • Case Information Displays: When using SendToExcel features and trying to push the results to an existing open instance of Microsoft Excel, Simulator would sometimes return and "Operation Unavailable" error. This could happen inf Microsoft Excel was busy doing something. We have modified it so that if this happens we will now wait 1.0 seconds and try again. If it then fails, we will instead just automatically open a new instance of Excel and push the data to this instance.
    • File Formats: When loading three-winding transformers from an EPC file, only the first three ratings are specified in the file for the secondary and tertiary windings. There was a bug where the ratings beyond the first three were not being initialized correctly to 0 and instead were being set to numbers in the e-40 range. This would result in very large % of Limit Used calculations and very negative ATC results. This has been fixed when loading an EPC file. When loading a PWB file that had been saved with this issue, this incorrect limits will now also be set to 0.
    • PV and QV Curve (PVQV) Tool: Added ability to identify QVCurve results by label.
    • Transient Stability: Fixed an initialization bug with REGC_A when internal XFMR StepX and/or StepR are specified in the power flow case. Intended modeling of REGC_A is with StepX and StepR as zero and StepTap = 1, and now these are set before initialization.

November 12, 2019

Features and Improvements

  • Case Information Displays: Added new field to InterfaceElement object called "NearBusRetain". This field is the same as NearBus, however it will retain the string that is entered here and write it back out later. The other NearBus field just uses the string to populate the appropriate near bus, but then throws the string away.
  • Transient Stability: Added support for new model named IEEEG1PID. This governor is very similar to IEEEG1, except that it replaced a lead-lag controller with a PID controller instead.
  • Transient Stability: When reading a DYR file, modified to convert the USRMDL model named "RAVGOV" so that it is translated to the new governor IEEEG1PID.
  • Bug Fixes

    • Case Information Displays: An access violation could result when opening the Jacobian case information display if area/zone/owner filters were applied. This has been fixed.
    • Transient Stability: Removed option to show Bus View from transient stability injection group models case information display. Bus views are not relevant for injection groups.
    • Transient Stability: Option to Pan to Object on Open Onelines on transient stability model case information displays should now work to pan to the object to which the model is assigned.
    • Transient Stability: Allowed the GP3 Relay Model to propagate to all generators in the case even when the generator to which the GP3 relay is attached does not have an active machine model
    • Transient Stability: Fixed potential numerical problem when using a CSVGN1 model which could occur with a particular set of input parameters.

November 7, 2019

Bug Fixes

  • File Formats: When opening a PWB file containing a Model Filter that includes a Model Plane, the Model Plane was not always being linked to the Model Filter Condition. This has been fixed.
  • Optimal Power Flow (OPF): Removed the field OPF_SolutionType on the object OPF_Options. This does not do anything.
  • Transient Stability: When reading a switched shunt model from a DYR file, if the bus did not exist it would cause an error. This has been fixed and the model is properly skipped then.
  • Transient Stability: Fixed bug with initializing the Pref-Controller WTGTRQ or WTTQA1 when the MVABase of the PrefController did not match the MVABase of the generator.

November 6, 2019

Features and Improvements

  • Transient Stability: When reading a DYR file, the OLTC1T and OLTC1 models are now automatically converted to an LTC1 model.
  • Bug Fixes

    • Power Flow Solution: Further refined the power flow solution when multiple continuous switched shunts are remotely regulating the same bus together.
    • Transient Stability: Fixed error when defining a MeasurementObject in transient stability to does not have an associated object with it. This doesn't make sense, but was causing an error. It will now just be ignored.

November 1, 2019

Features and Improvements

  • Transient Stability: Added the reading of USRMDL model SVSMO1U1 which is read as an SVSMO1 model.
  • Transient Stability: Added the reading of USRMDL model SVSMO1U2 which is read as an SVSMO1 model.
  • Transient Stability: Added the reading of USRMDL model SVSMO2U2 which is read as an SVSMO2 model.
  • Transient Stability: Added ability to read the SVSMO1T2 model from a DYR file which is read as an SVSMO1.
  • Transient Stability: Added ability to read the SVSMO2T2 model from a DYR file which is read as an SVSMO2.
  • Transient Stability: Added a new CHSVCT dynamic model for switched shunts.
  • Bug Fixes

    • File Formats: When reading an Areva RASMOM file, an access violation could occur if encountering an unknown TRIGCON GATE field. This has been fixed so than an error message is produced instead.
    • Power Flow Solution: Improved transformer tap switching consistency after a failed solution.
    • Transient Stability: Fixed duplicate event messages that could appear saying that the loss-of-field relay portion of a GP3 model can not be used with a GENCLS model.
    • Transient Stability: Modified to read USRMDL IEEEG1CDU and convert to a IEEEG1D model.
    • Transient Stability: Correctly normalizing the PrefInput into WTGTRQ_A_WTTQA1_PTI, if it has a Plant Controller, and if it is just an initialized constant.
    • Transient Stability: An access violation could result if creating a Measurement Object without an associated object. This has been fixed.

October 29, 2019

Features and Improvements

  • Transient Stability: Added a button on the Transient Limit Monitors tab of the transient stability dialog to "Re-evaluate to Get Limit Monitor Violations." This will re-evaluate stored results to determine limit monitor violations. First the results in RAM will be searched, and if not found, results in TSR files will be searched. If in Multiple Contingencies mode, all contingency results will be evaluated.
  • Transient Stability: Added support for a new relay model named LDS4 which is identical to LDS3 except that it includes two extra parameters Vthresh and Tv. When the voltage at the measured bus of the relay drops below Vthresh, then the relay will not respond until the voltage goes back above Vthresh for at least Tv seconds. While the relay is inhibited from acting this way it will also reset any stages of the relay that may have started their timer. Note however that if a stage had already made a decision to trip something then dropping below Vthresh will not stop this from happening.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Updated the script command TSLoadPTI() so that a 5th option parameter for MOD_REMOVE filename is now available.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed error in parsing fields from AUX files which had consecutive single quote characters embedded inside the string.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed how TSPlotSeries read from an AUX file are when the plot series referred to fields of a Measurement Model such as LDTRPMON.
    • Available Transfer Capability (ATC) Tool: When allowing users to specify the names of multiple ATC scenarios, prepend an underscore on the name if it matches a default name and the name is not in the appropriate order. The default names of generator scenarios are G0, G1, G2, etc. If a user decides that the names should be G1, G2, G3, etc., the resulting names will be _G1, _G2, _G3, etc.
    • Transient Stability: In the measurement object LDTRPMON which monitors the composite load model, the reported Other field values of Pld, xshn, and Pdg were being shown in per unit instead of in MW (off by a factor of the system MVABase and thus by default 100 times too small). As a result values for these 3 fields would show 2.5 instead of 250. This has been fixed. Also, the field name "xton" was showing up as "ston" which was a typo that has been fixed now too.
    • Transient Stability: Bug fix for WTTQA1, which was initializing Pref0 on the wrong base, and hence causing the initialized PI Input value to be non-zero.
    • Transient Stability: Added validation of the Ta parameter on the ESST1A exciter model to ensure it is not too small.
    • Transient Stability: Only generators with synchronous machine models can have a meaningful non-zero value for the power angle.
    • Transient Stability: Fixed bug reading zonedef for distrel when reading from a dyd file.

October 23, 2019

Features and Improvements

  • GIC: Added ability to show the substation input electric field values.
  • Bug Fixes

    • Transient Stability: Modified WT3E, WT3E1, and WT4E1 to better handle user-input in the Kip = 0 (gain on integrator PI Controller).
    • Transient Stability: Typically in PSLF the Extra Object or Extra Devices used the "! ! ! ! !" but it seems that the repc_a and repc_b used only the "! !". Fixed this.
    • Transient Stability: Added VKlr as an other field for EXST1_GE.

October 21, 2019

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added a new script command LoadPTISEQData(filename, version); The filename is the file being opened. Version is an integer representing what version of the SEQ file to open.
  • Transient Stability: added VPERHZ1 generator relay model that implements a Volts per Hertz definite time relay model. It has 5 zone (V/Hz and Time) settings, a measurement delay for per unit voltage and per unit speed (Note: model uses speed as a proxy for frequency), and a breaker delay.
  • Transient Stability: Modified the meaning of the "rrpwr" rate limit on real current for many renewable energy machine models. Previously this rate limit only applied to real current that was increasing in the positive direction. It will now apply to increasing the ABSOLUTE value of real current instead. Thus if the present real current is negative it will be a negative rate limit and if present real current is positive it will be a positive rate limit. This has become necessary as these machine models are being used for energy storage devices which can initialize real current as a negative value to represent charging. This impacts the models GEWTG, WT3G, WT4G, WT3G2, WT4G1, PV1G, REGC_A, REGC_B and REGC_C. The DER_A model had always been coded in this manner.
  • Bug Fixes

    • Transient Stability: Fixed a bug with the auto insert DISTRELAY feature. The auto insert feature was incorrectly placing the relay at the opposite end of the line from what the user indicated. This has been fixed.

October 18, 2019

Features and Improvements

  • Transient Stability: Adding support for changing GMD induced dc line voltage as a transient stability (really ds) event.
  • Bug Fixes

    • Transient Stability: Modified DGDER_A and DGPV load distributed generation models so that when defining their MBase as a negative value, we do not always base the MVABase on DistMW/abs(Mbase). It will now take the absolute value of the DistMW and DistMVar fields and take the larger of those two values and then divide by abs(MBase). This was done for the situation where DistMvar is much larger than DistMW. In extreme example, DistMW = 0, DistMvar <> 0. This is potentially possible if someone were modeling distributed energy storage, but the more likely situation is inadvertent user input. Regardless it will no longer cause software errors for this situation.
    • Transient Stability: Modified filtering associated with applying complex load model. Normally the filtering applies only to the load MW/Mvar portion of the load object and not the DistMW/DistMvar. If however there is not a dynamic model for the distributed generation then DistMW and DistMvar are substract from MW and Mvar and the Net values are used with the load characteristic. Simulator has been changed so that when the NetMW and NetMVar are being used then NetMW and NetMVar are used in the filtering features of the load characteristic

October 16, 2019

Features and Improvements

  • Transient Stability: Modified the LD1PAC (and thus LD1PAC_CMP which derives from this model and also CMPLDW, CMLD, and CMLWDWNF that contain this model). When the Tstall parameter is set to a negative number, then a hard-coded inverse time characteristic is implemented which replaces the definite time Vstall/Tstall characteristic. The curve implemented uses the following table to lookup a Tstall from the terminal voltage of the model (with a linear interpolation between points). Also the inverse time internal state is automatically reset whenever the terminal voltage goes above 0.565 per unit.
    Vterm Tstall (in cycles)
    0.000 2
    0.450 2
    0.490 3
    0.550 12
    0.565 15
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed error in Move script command that was not allowing the change of CircuitID for one leg of a 3 winding transformer
    • File Formats: When loading PTI RAW files for Branches, LineShunts that were 0 MW and 0 MVar were being created. This did not impact the simulation but was strange, so has been fixed.

October 11, 2019

Features and Improvements

  • Fault Analysis: Added option on the fault analysis dialog to open and save a version 34 PSS/E sequence data file.
  • File Formats: Added code to abort hdbexport reading when the fields in the records don't match the expected fields in the header. This is in response to several files with string fields without quotes. These fields contained commas, which was causing an access violation attempting to access the header for a field that doesn't exist.
  • Simulator Automation Server (SimAuto): Changing RegSimAuto.exe program so that the dialog that appears shows the currently registered executable
  • Transient Stability: Reads PTI DYR model SVSMO2T2. Converts to SVSMO2. Writes out PTI DYR model SVSMO2T2
  • Transient Stability: Added a new synchronous machine model GENQEC which has the following features that improve upon the GENROU/GENSAL models. This GENQEC model can be used with both salient pole and round rotor synchronous machines. The purpose of this model is to replace GENROU/GENSAL and GENTPF/GENTPJ type models.
    1. Ignoring saturation, model has the same as differential equations as GENROU/GENSAL
    2. Saturation treatment is similar to GENTPF/GENTPJ in that saturation is modeled by applying multiplicative term to the machine input parameters as appropriate
    3. Allows Xqpp <> Xdpp (allows sub-transient saliency), which GENROU/GENSAL did not.
    4. Added a flag to indicate what saturation function to use. Choices are 0: exponential, 1: scaled quadratic, 2: quadratic
    5. Added a Kw compensation term which can model the impact of stator current on the steady state relationship between field current and terminal voltage relationship. This models the fact that the linear relationship (slope) between steady state field current and terminal voltage changes with stator current.
    (Also Removed the test synchronous machine models GENPWS and GENTPW.)
  • User Interface Dialogs: Added new fields for Area and Zone for a Injection Change in LineLoadingReplicator
  • User Interface Dialogs: Update in Line Loading Replicator Tool - Now able to choose multiple injection groups, instead of just one. Participation factor is not relevant, because the injection group is just being used as a basket of sink/source elements (gens and loads)
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed access violation that could occur with the SetData script command if no fields are specified.
    • Auxiliary Files (SCRIPT and DATA Sections): Added optional fieldlist parameter to the ATCWriteToText and ATCWriteToExcel script commands. If the fieldlist is specified, the results will be saved with these specified fields. If not specified, the results will be saved with the fields that are specified with the TransferLimiter DataGrid. It is possible that the results could be blank if the TransferLimiter DataGrid has not been initialized by either opening the ATC dialog or loading the DataGrid settings from an auxiliary file. To make sure that results are stored and the desired fields are included, it is suggested that the fieldlist option be used.
      The format of the script commands are now:
      ATCWriteToText("filename", filetype, [fieldlist]);
      ATCWriteToExcel("worksheetname", [fieldlist]);
    • Time Step Simulation: Fixed error check when Kpp = 0 on the WT3E1 model. It was supposed to check if Kip was also 0.0 and return this as an error, but this was not working properly.
    • Time Step Simulation: Fixed error in implementation of ABBSVC1 model when no transformer branch has been specified.
    • Time Step Simulation: If specifying a distributed generation model for the entire case, we were including this transient stability model in the list of states even for loads which do not have any distributed generation (DistMW = 0 and DistMvar = 0). This did not effect the numerical simulation, but was strange and has been removed.
    • Time Step Simulation: On the Transient Stability Plot dialog, when selecting a multiple devices we automatically update the strings underneath folders such as "Exciter State" or "Machine State" to reflect the names of fields for the objects which have been selected. If "State 2" for all the selected devices where the same string we would show that string, and otherwise we would just show "State 2" instead. When selecting a very large number of generators or loads (> 500) this was making the user interface sluggish. This has been modified so if more than 500 devices are selected we always only show the "State 2" or the equivalent.
    • Transient Stability: Fixed a bug with run validation in TS. It was creating an Item not found message when a generator dot no had an Island. This only occurred on machine models that could be closed.

October 3, 2019

Features and Improvements

  • Bus View and Substation View Onelines: The information stored in the system registry for Bus View settings will now include the name of the Custom View if one is chosen to be the current view. This will be retained when Simulator is closed and will be applied when reopening Simulator and used with any PWB if the named custom view is saved with the PWB.
  • Contingency Analysis Tool: Added options on the local menu of the contingency case information display under the Save As menu entry for "PTI Contingency File..." and "PTI Contingency File (only selected records)...".
  • File Formats: When reading an hdbexport CSV file, modified how we read multiple XFLIM records which have pointers to the same XF record. Normally this won't happen, but users are able export a CSV file with multiple XFLIM records. Previously we would read all of them an continue overwriting the ABC limits and thus the final XFLIM record encountered would override all others. In talking with customers the preference was to read them into limits DEF and beyond instead. Now when reading
    1. The first XFLIM record will take parameters LIMIT1_XFLIM, LIMIT2_XFLIM, LIMIT3_XFLIM and put them into limits A, B, and C.
    2. The second XFLIM record will populate D, E, F
    3. The third XFLIM record will populate G, H, I
    4. The fourth XFLIM record will populate J, K, L
    5. The fifth XFLIM record will populate M, N, O
    All subsequent XFLIM records for the same XF record would then be ignored.
    The same logic was added taking LNLIM and assigning limits to LN records, and for taking ZBLIM records and assigning limits to ZBR records.
  • Transient Stability: Reads PTI DYR model SVSMO1T2. Converts to SVSMO1. Writes out PTI DYR model SVSMO1T2
  • Bug Fixes

    • File Formats: When changing switched shunt data within the Simulator GUI or through an auxiliary file for GE specific fields that are associated with EPC files, fields that can be associated with both SVD and Shunt data in an EPC file, such as GE In Service Date and GE Retirement Date, may not have been set correctly. This has been fixed. Information was correct if it was read directly from an EPC.
    • File Formats: When reading PTI sequence data the circuit IDs of transformers were not always being identified correctly resulting in sequence information not being read. This has been fixed.
    • User Interface Dialogs: Removed unused options from the local menu of the LODF Screening Summary case information display.

September 30, 2019

Bug Fixes

  • Distributed Computation: Fixing distributed computation when hardware key licensing fails
  • File Formats: When setting the EPC datein and dateout fields through an auxiliary file, trim any extra spaces. These fields are supposed to be integers and conversion to an integer can fail with extra blanks. Trim these fields when writing to an EPC file to prevent invalid integer errors.
  • File Formats: Fixed bug reading in SUBDATA for contingency elements. When a generator was referenced by a label, which happened to be a numeric value, it was matching to a bus number instead of the generator label. This has been fixed. This is detected by the missing ID value in the generator key fields.

September 26, 2019

Features and Improvements

  • Contingency Analysis Tool: Added the 'Disable D-FACTS' option to the contingency solution options.
  • Bug Fixes

    • Contingency Analysis: Fixed access violation that would result if starting a contingency analysis run while the All Violations case information display is open and contains violations.
    • File Formats: Fixed a bug that would save a PWD file as blank.
    • Transient Stability: Made changes to user defined models in TSUserDefined.pas, so that validation errors are not produced when using a user-defined machine model with any (library or user-defined) exciter model.
    • User Interface Dialogs: On the Simulator Options dialog fixed the mouse over hint for the Disable D-FACTS Control option.
    • User Interface Dialogs: When dialogs were maximized inside the main Simulator window and a dialog was already open but hidden behind other dialogs, clicking on the option to open that dialog would bring the dialog to the front but not display it properly as maximized. The top caption of the dialog would be shown and some option buttons and the bottom of the dialog could be hidden behind the bottom of the main Simulator window. This was happening with the Scale dialog and Limit Monitoring Settings dialog and various others. This has been fixed.

September 25, 2019

Bug Fixes

  • File Formats: Fixed a bug that would produce an error when saving a PWD file.

September 24, 2019

Features and Improvements

  • File Formats: When loading PTI MON file now support loading an interface when specified in this format: MONITOR flowgate 3 'My Flowgate' biratings -10000 10000
  • Transient Stability: Implemented SignalStabStabilizer to provide reference signals into a stabilizer input. Inputs are similar to the InfiniteBusSignalGenerator.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug in the LoadCSV script command. The command was crashing when the specified file did not exist. Now, it checks for the file's existence and returns an error message when it's not there.
    • File Formats: Fixed a bug that would not allow the same PWB or PWD file to be loaded at the same time by different processes.
    • Sensitivity Calculations: Fixed access violation when trying to calculate a TLR on an open branch.

September 21, 2019

Bug Fixes

  • General: Fixed an error that resulted if trying to save a PWB or PWD file that already existed.

September 20, 2019

Features and Improvements

  • Transient Stability: Added ability to read the CMLDxxU2 composite load model. This is the same as CMLDxxU1 except that it includes the frcel (fraction of electronic load the reconnects). This will be read into a CMLD model which now also includes this additional input parameter frcel.
  • Transient Stability: Added new ModalAnalysis button on the Ribbon.
  • Transient Stability: Modified Modal Analysis to have option of storing results; default is false.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: Fixed access violations that could occur when running one of the iterated ATC methods when oneline diagrams are open.
    • Contingency Analysis: When using the contingency option to specify Generator Maximum MW Response, the Max MW and Min MW limits are adjusted for generators with a maximum response specified. The change in limits will restrict how far the generator can move during the post-contingency solution. At the end of the contingency solution the limits are now restored to their original values. Previously they were kept at the reduced limits and this could result in incorrect generator responses if applying additional contingencies on top of the first contingency.
    • Power Flow Solution: When checking switched shunts in the voltage control loop of the power flow solution, a tolerance is now included so that shunts will only move if the voltage at the regulated bus is different than the target voltage by this tolerance. This will help prevent switched shunt oscillations especially in situations where generators are regulating the same bus as switched shunts.
    • Transient Stability: Fixed the caption on the Stability > Terminal and State > Bus/Setpoint Values page of the generator dialog from "Polar" to "Rectangular" for one of the "Terminal Voltage and Current into Bus" fields.
    • Transient Stability: Changed the order of fields on the case info display showing the CompLoad load characteristic objects.
    • Transient Stability: When loading a DYR file and loading a machine, exciter, governor, or stabilizer we now make sure that if an existing model of a different name exists at the generator, then the newly created and loaded model from the DYR file becomes the active model.
    • Transient Stability: Prevent errors by preventing generator relay from being included in calculations if its generator is not inservice.
    • User Interface Dialogs: Reduced the amount of window flicker that occurs when moving or resizing windows.

September 16, 2019

Features and Improvements

  • Contingency Analysis Tool: (1) Added new option under the Other > button and then Manage Contingency Definitions called "Set Selected Field for Remedial Actions and Dependencies."
    (2) Added two new options on the local menu of the Remedial Action case information display: (a) "Set Selected Field for Dependencies" and (b) "Set Selected Field for Dependencies (only selected records)".

    All of these options are meant to help identify the Model Filters, Model Conditions, Model Planes, and Model Expressions that are being used by user specified Remedial Actions and NOT used by other objects. If for example a user specified Remedial Action is using a Model Filter and a Transient Stability Contingency Element also is using that Model Filter, that Model Filter will NOT have its Selected field set to YES. At the beginning of the implementation of each of these options the Selected field is set to NO for all Remedial Actions, Model Filters, Model Conditions, Model Planes, and Model Expressions. In the descriptions below "dependencies" will mean objects of type Model Filter, Model Condition, Model Plane, or Model Expression.
    Option (1) will check all Remedial Actions in the case and set the Selected field to YES for any dependencies of the Remedial Actions. The Selected field for Remedial Actions will also be set to YES.
    Option (2a) will check all Remedial Actions that are shown in the Remedial Action case information display. This might be a subset of all Remedial Actions if filtering is in use. The Selected field will be set to YES for any dependencies of these Remedial Actions and the Selected field for these Remedial Actions will also be set to YES.
    Option (2b) will check only the Remedial Actions that have been selected in the Remedial Actions case information display by using the mouse. The Selected field will be set to YES for any dependencies of these Remedial Actions and the Selected field for these Remedial Actions will also be set to YES.
  • User Interface Dialogs: Added dropdown on Model Expression dialog to change the key field identifier to use for variables on the dialog. This option only affects the key field identifier to use for this dialog and does not impact the setting used with case information display options.
  • Bug Fixes

    • File Formats: Fixed a bug that would prevent a PTI CON file from loading.
    • GIC: Allowed XFConfig to work with primary and secondary fields, both for display and pasting.
    • Oneline Diagrams: Added options with right-click menus to format oneline fields while in Edit mode if only a single field is selected. Previously this could only be done if more than one oneline object was selected.
    • Transient Stability: Fixed change from August 8, 2019 patch that was preventing the modal analysis signal dialog from showing.
    • Transient Stability: Fixed bug that was preventing the modal analysis Iterative Matrix Pencil from working.

September 10, 2019

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): SendToExcel Script Command now validates to ensure that the workbookname is not an empty string.
  • File Formats: Fixed access violation when reading contingency records from an Areva EMS file.
  • General: Fixed installation to properly register SimAuto.
  • GIC: Fixed bug when pasting GICXFORMER info by primary and secondary bus numbers.
  • Oneline Diagrams: Fixed an access violation that would occur when closing a oneline for which a Display Explorer is also open.
  • Optimal Power Flow (OPF): In OPF solution when using the minimum control change option, the phase shifters and DC Lines controls were not working properly and instead were using a cost function centered around zero instead of the present operating point. This has been fixed.
  • Transient Stability: Fixed treatment of damping on the WTGT_A model.
  • Transient Stability: Modification of WTGT_B mechanical model for wind turbines.
  • Transient Stability: When reading a DYR file which contains the USRMDL with the name DERAU1, Simulator will automatically convert that to the DER_A model.
  • User Interface Dialogs: When trying to change the ID of a branch from the branch dialog while in Edit mode, an error for "Cannot make a visible window modal" could result. This has been fixed.

September 4, 2019

Features and Improvements

  • Case Information Displays: Added new case information display option regarding whether to "Show prompt about saving SUBDATA to AUX". This impacts the Generator and Load case information display which previously had prompted the user regarding whether to store the ReactiveCapability or BidCurve information as a SUBDATA section of each object. The user will now be able to choose "Never" and this dialog will no longer appear, though it can be added back by changing the new Simulator Option to show these again.
  • User Interface Dialogs: On dialog/window system menus found by left clicking on the PowerWorld logo in the caption of a dialog, there are now options for "Export" and "Copy to Clipboard" that export or copy images of the dialog.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug that would not allow the LoadAXD script command to load an AXD file into a oneline that doesn't already exist.
    • Case Information Displays: When listing the Areas, either by Name or Number, that are assigned to a Zone, include gens, loads, and shunts along with buses. Previously only buses were being included.
    • Case Information Displays: When listing the Zones, either by Name or Number, that are assigned to an Area, include gens, loads, and shunts along with buses. Previously only buses were being included.
    • Case Information Displays: Added Case Info Customizations for the following contingency related case information displays: Generator Post-Contingency AGC, Bus Load Throw Over, Generator Maximum MW Response, Generator Line Drop and RCC, and Switched Shunt Post CTG.
    • General: Closing a case containing many injection groups that include other injection groups could be very slow. This has been fixed.
    • Power Flow Solution: Fixed log messages regarding the AGC changing generator MW outputs. They should have been listing the area that was resulting in the change in MW.
    • PV and QV Curve (PVQV) Tool: Removed extra dialog that pops up briefly before opening the PV dialog.
    • Transient Stability: When transferring the Transient Stability operating point to view inside the case information displays in Simulator, errors were appearing related to setting generator voltage setpoints that should not have been appearing. This has been fixed.
    • User Interface Dialogs: The plotting of a reactive capability curve from user-specified points was not working properly. This has been fixed and diamonds have been added to the display to show the points.
    • User Interface Dialogs: On the bus dialog while in Run mode the Selected checkbox and other options on the Custom tab were not being updated to reflect the values associated with the current bus when the dialog was opened unless the Simulator license key included the OPF add-on. This has been fixed. The values set on the dialog were being transferred to the bus when the dialog was closed with the OK button or Save was clicked.

August 29, 2019

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug in CalculateLODFMatrix script command. There was a bug using the ALL qualifier to monitor ALL of the interfaces. The code was accessing the monitor filter incorrectly.
  • General: Fixed a bug where the impedance correction table was not working properly. The table was using the range of the values in the table to determine whether to use the phase or tap ratio to lookup in the table. Now, the type of value is determined correctly before looking up the impedance in the correction table.
  • User Interface Dialogs: On the Auto Insertion of Injection Groups dialog the Custom Field dropdowns were not being updated if the Element Type changed. This has been fixed.

August 28, 2019

Features and Improvements

  • User Interface Dialogs: When defining Model Conditions and Model Expressions and using the Choose a Field dialog to select a field for the condition or expression, there is now an option "Show Transient Stability Remedial Action Fields". When this option is checked, only the fields that are valid for being evaluated each time step during transient stability analysis will be shown.
  • Bug Fixes

    • Contingency Analysis: Certain categories of contingency violations could not be loaded from an auxiliary file or correctly returned when using distributed contingency analysis. These include the Change Bus dV/dQ, Change Bus Disconnected, and Bus Neg dV/dQ violation categories. This has been fixed.
    • Contingency Analysis: An access violation could occur when deleting contingency violations from the following categories: Change Bus dV/dQ, Change Bus Disconnected, and Bus Neg dV/dQ. This has been fixed.
    • Distributed Computation: For Distributed Contingency Analysis an error would occur when including the Advanced Limit Monitoring options to "Report changes in bus dV/dQ sensitivity" or "Report as a violation if a bus becomes disconnected." This has been fixed.
    • General: Updated autoload function. Now the files are renamed with an underscore '_' character before being loaded. This allows us to check for files that need to be deleted before loading a new file.
    • Sensitivity Calculations: Fixed access violation when calculating interface sensitivities on the Flow and Voltage Sensitivities dialog under Single Meter, Multiple Transfers.

August 26, 2019

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): When loading Contingency Elements, Remedial Action Elements, and Global Actions from an auxiliary file it was possible that the Model Criteria field could be set to an incorrect entry if the Model Criteria field was not specified in the field list in the auxiliary file. The Model Criteria should have been set as blank instead of an entry. This has been fixed.
  • Auxiliary Files (SCRIPT and DATA Sections): When loading Remedial Action Elements from an auxiliary file it was possible that the Arming Criteria field could be set to an incorrect entry if the Arming Criteria field was not specified in the field list in the auxiliary file. The Arming Criteria should have been set as blank instead of an entry. This has been fixed.
  • Auxiliary Files (SCRIPT and DATA Sections): It was possible that blank names could be specified for Model Filters, Model Conditions, Model Planes, and Model Expressions when loading from an auxiliary file. A non-blank name must be specified for these objects. This has been fixed.

August 23, 2019

Bug Fixes

  • Transient Stability: Handled strange input data for WTGT_A when Ht=0. Modified to automatically assume this represents a single-mass model and internally H=Ht+Hg. Previous expectation was that the user would set Ht and then make Hg=0. This handles situation when the user does the opposite and sets Ht=0 while giving a value for Hg.
  • Transient Stability: Fixed bug when REPC_B was assigned to a generator and then not connected to any generators. This was causing inconsistent results. The expectation is that the REPC_B model must connect its output to itself.
  • User Interface Dialogs: When editing the MVABase of the winding of a three-winding transformer on the Three-Winding Transformer Information dialog it was not taking any edits of the MVABases. You were only able to edit those values on the case information displays and NOT on the dialog. That has been fixed.

August 19, 2019

Features and Improvements

  • Transient Stability: Added a button on the Options > Remedial Actions page of the transient stability dialog to "Show Valid Remedial Action Fields" that will display a case information display with all fields that can be evaluated each transient stability time step.
  • Transient Stability: Added REGC_C model.
  • Bug Fixes

    • File Formats: Modified how the System-Wide settings of the RAW version 34 file are read so that we properly read files even when particular parameters are omitted in that format. Previously we were failing to read the file when values are omitted. The values are all entered as "Key=Value" strings, so we can just parse these and lookup the keys that we fine.
    • Transient Stability: Renamed governor model GGOV1DU to GGOV1D.
    • Transient Stability: When including remedial actions in transient stability, the remedial action definitions would be ignored if not using the option with contingency analysis to "Save contingency analysis definitions/results in the case PWB file." This has been fixed.
    • Transient Stability: Fixed TSAutoInsertDistRelay script command. Added parameters for AddTo, AddFrom, Transfer Trip, and Shape. The format is now:
      TSAutoInsertDistRelay(0.9,InsertRelayAtFromBus, InsertRelayAtToBus, DoTransferTrip, Shape, filtername).
    • Transient Stability: Improved validation of remedial actions used in transient stability.
    • Transient Stability: Added fields that are allowed to be evaluated at each transient stability timestep: Branch MW From, Branch MW To, Branch Mvar From, Branch Mvar To, Branch MVA From, Branch MVA To, Branch Amps From, Branch Amps To, Bus PU Volt, and Bus Volt (kV).
    • Transient Stability: Fixed a bug that would not correctly identify line relay models when loading from an auxiliary file.

August 13, 2019

Features and Improvements

  • General: Added ability to automatically load a PWB, AUX, RAW, or EPC file whenever a new file appears in a directory. The file will immediately be opened and then the file will be deleted!
  • Bug Fixes

    • File Formats: Modified the Save RAW with Options dialog to allow Version 34 RAW files to be opened and saved.
    • File Formats: When reading an EPC file load record a climate zone of " " (double quote, space, double quote) was being read and a climate zone created without stripping of the double quotes resulting in a very strangely named LoadModelGroup in Simulator. Then on a subsequent export of the load record to an EPC it would encase that entire string inside double quotes resulting in "" "". This then appeared to be two strings on the next import of the EPC file messing up entries after the climate zone in the EPC file. This has been fixed.
    • Integrated Topology Processing (ITP): Added checks for the ITP add-on when using the 'When using Integrated Topology Processing, monitor only the primary bus for each superbus' option. This option was being used when the user did not have the ITP add-on and when the case was not marked as a full topology case. This was causing the contingency analysis to give confusing results: they were being limited to primary buses when this was not the expected behavior. Now, the option will check that the user has the ITP add-on and that the case is marked as a full topology case before filtering the results. In addition, the checkbox will be hidden if the user does not have the ITP add-on.
    • Transient Stability: When testing to see if the Intermountain Power Project (IPP) DC Line should be automatically included in the stability model, modified so this model is not included if the actual device is out of service in the initial case. This was causing access violation.
    • Transient Stability: Fixed bugs with initializing a DC line that is out of service in a transient stability simulation.
    • Transient Stability: Fixed error when initially energizing a bus with a ZIP load by closing in branches to energize the bus during a transient stability run.

August 9, 2019

Bug Fixes

  • Transient Stability: Fixed a bug where Plot images were not being saved properly during Distributed TS runs.

August 8, 2019

Features and Improvements

  • Transient Stability: Added a new Injection Group transient stability model named GroupMSS.
  • User Interface Dialogs: Modified the dialog that appears offering the user the ability to add "Case Comments" when choosing options to Save Case, Save Case As, Save Case with Comments, or Save Case As with Comments. Previously once you got to that dialog there was no way to "Abort the Save". Hitting the X in the upper right would just skip adding the comment but you would still save the case. There are now separate buttons to Add a comment, Skip adding comment, and Abort Save all together. Also removed the X in the upper-right of this dialog to force the user to choose one of the buttons making it very clear what is desired.
  • Bug Fixes

    • Case Information Displays: Fixed an access violation that could result when using the option to Export Case Object Fields related to the new ModelPlane object
    • Transient Stability: Bug fix in Modal Analysis for catching exception during floating point overflow, which happens rarely, but typically while using a large time window, or a time window which has a "discontinuous" signal (like when a generator opens up, causing a sudden change)

August 6, 2019

Features and Improvements

  • Transient Stability: Added WTGT_B mechanical model for a type 4 wind turbine.
  • Bug Fixes

    • Case Information Displays: Fixed error in calculating the amps of a load when the load is disconnected.
    • Transient Stability: When an IEEEG1 or CRCMGV were configured with the low pressure generator online AND the high pressure generator off-line, this resulted in an access violation. The governor model is assigned to the high-pressure generator which is off-line in this situation and was causing bad behavior. For now this has been fixed by ignoring the governor and thus the low pressure genenerator will be simulated without a governor.
    • Transient Stability: Added storage of the option to Include Remedial Actions in Transient Analysis to PWB files which will also allow this option to be included with distributed computing. Remedial actions had not been included with the distributed computing runs but this has been fixed.

August 2, 2019

Features and Improvements

  • File Formats: Added bad data handling when reading an EPC file with a generator with cont_mode = 4 if the Vcsched is set to an unreasonable value. (We were seeing cases where value was set to 24.000 as user entered value in kV mistakenly). When Vcsched is specified outside the range 0.85 - 1.15 we will instead assuming cont_mode = 0, the regulated bus is the terminal bus, and the VoltSet is the present terminal voltage.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: Fixed Access Violation that would occur when using the Available Transfer Capability tool when using the Iterated Solution Methods. This bug only impacted Version 21.
    • File Formats: Added ability to read the cont_mode = 4 from a generator in an EPC file. This then uses a field "Vcsched" field. When reading cont_mode = 4, the generator is set to as follows
      VoltSet = Vcsched
      UseLineDrop = YES
      Rcomp = RcompEPC * SBase/MVABase
      Xcomp = XcompEPC * SBase/MVABase
    • Time Step Simulation: Fixed bug when using a file Data Source on the Model Analysis Form when no plots have been defined. Even though the plots is not being used as the source an error would occur. Now a file can be specified without needing plots defined as well.