Simulator 20 Patches

New Features

Bug Fixes

Date

April 24, 2018

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): When choosing fields on the Auxiliary File Export Format Description, the fields were always added to the end of the list instead of the location to which you have dragged the fields. This has been fixed.
  • Auxiliary Files (SCRIPT and DATA Sections): On the Auxiliary File Export Format Description dialog, when clicking the Modify button to modify the fields for a particular object type, if the Cancel button was hit on the subsequent dialog then you would loose the digits and decimal places you had chosen for the list of fields. This has been fixed.
  • Auxiliary Files (SCRIPT and DATA Sections): On the Auxiliary File Export Format Description dialog, when clicking the Modify button, and then dragging fields from the list of available fields onto the field list, Simulator would always add the fields at the end of the list. This has been fixed so that fields are added to the location to which they are dragged.
  • File Formats: Reading the same PowerWorld AUX file by different Simulator instances could cause an error because the same file could not be read simultaneously. There doesn't need to be a restriction on separate instances of Simulator reading the same AUX file, so this restriction has been removed.

April 23, 2018

Features and Improvements

  • Difference Case Tool: Added Difference Case tool support for generator fields CTGPreventAGC, CTGPartFact, CTGMaxResp, CTGMaxRespPerc, Online
  • Difference Case Tool: Added Difference Case tool support for branch field RegBus, RegBusNumUsed
  • Transient Stability: Added new right-click option under Save As on a case information displays for Generator, Shunt, LineShunt, and Branch objects, as well as any transient stability dynamic model object for one of these 4 objects. The new option says "DYD Format (only models of selected records)" and will store a DYD file snippet for the objects and models selected. Also include support for some Load objects and models as appropriate.
  • Bug Fixes

    • QV Curve Tool: When choosing to save results to file with a QV run, temporary files are created in a specially named directory in an attempt to limit the amount of computer memory used. There were two issues being reported related to these temporary files. (1) Windows has a limit of 260 characters for the name of a file path, which includes the directory and the file name. The temporary files would not be created, but no error would be issued until an attempt was made to access the file. A validation check has been added at the beginning of a QV run that checks to see if any of the temporary file paths would be too long, and if so, the QV run will not continue. (2) Some users have reported that the temporary directory is not being created, which also results in the temporary files not being created and no results existing for studied scenarios. Additional error checking has been added during the creation of the temporary directory, and if this fails, the QV run cannot continue.

April 20, 2018

Features and Improvements

  • Transient Stability: Modified DER_A model by adding two new parameters Iqh1 and Iql1 as limits on the extra reactive current injection path.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed access violation that could occur when trying to change the filter for an object type in an Aux Export Format Description.
    • Power Flow Solution: Fixed a bug in which super area AGC was not disabled when the super area spans multiple islands that contain more than one super area or areas that are not in the super area.
    • Transient Stability: Result Events in Transient stability related to the Distribution Equivalent Model which relate to the LTC1 model on the transformer switching the result even object was being reported as a blank. This was because this is for the internal transformer which is created only inside the transient stability simulation. We will now report the Load object's identification to indicate where the LTC1 model is coming from.

April 18, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added option "Use Defined Names in Variable Name Locations" to the Case Information Display options. This will display certain fields that are able to be named (CustomFloat, CustomInteger, CustomString, CustomExpression, CustomExpressionStr, DataCheck, DataCheckAggr, and CalcField) to be shown with the name replacing the location number when the fields are shown as their variable names. As an example, CustomFloat:1 will appear as CustomFloat:The name I gave this float.
  • General: When a user chose to open a case file that was NOT a PWB file, but left the "Files of Type" set to PWB this would cause an error (as it should). This error has however been modified to more gracefully abort the read and indicate to the user that the file type is probably wrong.
  • Transient Stability: Added AC9C Exciter Model
  • Bug Fixes

    • GIC: Fixed bugs with initial GIC values not being set. Also, now with GICs are included in transient stability depends on whether they are included in the power flow. Added ability to include snapshot GICs in the transient stability.
    • Time Step Simulation: Time point column header for "Total MVA Load" should have been "Total Mvar Load" and has been fixed.
    • Transient Stability: Added the ability for generators to close at buses that were previously not energized.
    • Transient Stability: For the REEC_A/B/C models, when Tpord = 0 then the Pmax/Pmin limits were not being properly enforced. This has been fixed.

April 12, 2018

Features and Improvements

  • Transient Stability: Added result storage of Area ACE value
  • Transient Stability: Modified the LHFRT model so that when obtaining the frequency measurement at the bus, if the voltage is below the "Minimum PU voltage for relay frequency measurement", then the frequency is treated as at nominal
  • Transient Stability: Added a new Gen object field called "TSGovMWCap" which returns the MW Base of the active dynamic governor model if available. If either no governer is active or the active governor does not have a MW Base parameter, then this field will appear as blank.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When using the RenumberMSLineDummyBuses script command, no dummy buses would be renumbered unless the optional parameter for the Delimiter was specified. This has been fixed. If no delimiter is specified, either a space or a comma will work as a delimiter.
    • Power Flow Solution: In the pre-processing step of the overall power flow solution, an estimate of generation changes is done if using island AGC control. This estimate is meant to prevent excessive MW change from going to the island slack, which could cause a power flow failure. When loading a PWB file, we were assuming that the case was solved which meant that this estimate of generation changes was not done and could lead to a power flow failure. At the end of each successful power flow solution, a loss percent value is stored for each island that will be used for subsequent power flow solutions. This loss percent value is used for the next power flow solution during the pre-processing step to estimate generation changes required to meet load MW, loss MW, shunt MW, and dc line interchange. This loss percent value will now be stored in PWB files so that if a case for which no power flow solution is attempted is saved to a file and re-loaded, the same loss percent value will be used when trying to solve the power flow solution after re-loading.
    • Power Flow Solution: Fixed another issue with the svc smsmo2 to prevent oscillations. Now it will move the shunt only if it improves the voltage or the voltage movement is greater than a tolerance and greater than the current voltage difference from the target voltage value. Also it checks that the voltage difference between new B value voltage and the target and the difference between old B value voltage and the target is greater than a tolerance. This prevents oscillations from cases in which the solution was already close enough.
    • Transient Stability: There was an error in the GGOV1 model when a non-zero value of dB was specified and a non-zero value of R was specified. This was been fixed.
    • Transient Stability: Modified to allow closing in generators in transient stability if they did not have a machine model specified. They will be modeled as a constant current injection.

April 9, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added concise variable names DynamicFormatting objects
  • Case Information Displays: Cleaned up the field descriptions and column headers for DynamicFormatting objects.
  • Contingency Analysis Tool: OPENCBS and CLOSECBS contingency actions that are not able to identify breakers will now open or close the device meant to be acted upon by breakers. This will allow the same contingency definitions to be used in full topology cases containing all breakers and hybrid or planning models that do not contain breakers for all devices.
  • Data Checks: Added new ability to define DataCheck objects. These objects allow you to define by name an object that examines a particular ObjectType with a particular Criteria and then automatically builds a dialog showing you all objects that meet these data checks. In addition the Data Check dialog also provides summaries of counts of objects meeting (or not meeting) these data checks by aggregation objects of Area, Zone, Owner, and DataMaintainer.
  • Power Flow Solution: When on island based AGC control and an island does not have any controllable generators, the message in the log will now indicate which island by showing the number of the island slack bus.
  • Transient Stability: Added AC5C exciter model
  • Transient Stability: Added AC7C exciter model
  • Transient Stability: Added AC8C exciter model
  • Bug Fixes

    • Contingency Analysis: When using OPENCBS and CLOSECBS contingency actions and contingencies contain multiple devices that end up using the same set of breakers, it was possible that the actions were not properly performed if the original actions were defined with different Model Criteria, Status, Arming Criteria, Arming Status, or Time Delay. Breaker actions were not being included for all of these different combinations. This has been fixed.
    • Data Checks: Added new ability to define DataCheck objects. These objects allow you to define by name an object that examines a particular ObjectType with a particular Criteria and then automatically builds a dialog showing you all objects that meet these data checks. In addition the Data Check dialog also provides summaries of counts of objects meeting (or not meeting) these data checks by aggregation objects of Area, Zone, Owner, and DataMaintainer.
    • File Formats: When loading an EPC file, if a DC system has exactly 2 converters, 2 dc buses, and 1 dc line, then Simulator creates a 2 terminal DC line object. There was a bug with this conversion for determining the metered end of the two-terminal DCTransmissionLIne if the first bus listed in the EPC file DC line record was the inverter bus instead of the rectifier. This has been fixed.
    • File Formats: Reading the same RAW, EPC, or Areva CSV file by different Simulator instances could cause an error because the same file could not be read simultaneously. There doesn't need to be a restriction on separate instances of Simulator reading the same file, so this restriction has been removed.
    • Power Flow Solution: Fixed power flow solution failure in situations when the DC transmission line control resulted in the tap ratio oscillating between two values where one tap resulted in the firing angle being just below the minimum firing angle and the second tap resulted in the firing angle being safely above the minimum firing angle. In some situations this could resulted in the voltage control loop of the power flow solution oscillating between these two states. Simulator will now automatically pick the DC tap value that results in the firing angle being above the minimum firing angle.
    • Power Flow Solution: When changing topology to combine viable islands together, the loss percentage for the new island is determined from the loss percentage of the islands that were previously viable. The percentage was being chosen somewhat randomly and could result in picking a loss percentage that was not appropriate for the new island. This would result in a failed power flow solution. Now the loss percentage is chosen from the original island that had the most load.
    • Power Flow Solution: Fixed an bug in which svsmo2 were oscillating and were not stopping the movement of the shunt in the power flow solution.
    • Power Flow Solution: Fixed bug that would not check if SVSMO2 type SVCs need to operate if other non-SVC shunts had moved in the same voltage control loop.
    • PV and QV Curve (PVQV) Tool: Fixed a bug that would prevent the individual curve files from being created during a QV run. These files are used to save memory when using the option to Save Results to File.

March 28, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): The SaveJacobian script command will now allow DC to be specified for the JacForm parameter. This will save the B' matrix for the dc power flow.
  • Case Information Displays: Added a new field to a DataMaintainer called "AllowEdit". Setting this field to NO will mean that for objects that are maintained by this DataMaintainer, case information display editing will not be allowed nor will modifying an fields of those objects using AUX files or script commands.
  • File Formats: When loading an EPC file, if a generator is set to cont_mode = 2, but the power factor given is 0.0, then this is inconsistent data. In this situation, Simulator will now set pf = 0.01 and write a warning to the message log.
  • File Formats: When loading an EPC file, if a generator is set to cont_mode = 3, but the power factor given is 0.0, then this is impossible data (would result in infinite Mvar output). In this situation, Simulator will now change the cont_mode to 1 which is equivalent to setting AVR = NO in Simulator. A warning will also be written to the message log.
  • Bug Fixes

    • Transient Stability: Fixed bug in the initialization of the WTGTRQ_A model when the MVABase of the model is different than the MVA Base of the generator.
    • Transient Stability: For REPC_B model, the specification of RefFlag = 2 (constant power factor control) was not being handle properly and was being treated internally instead as RefFlag = 1 (constant voltage). This has been fixed.
    • Transient Stability: For REPC_B model, when specifying RefFlag = 2 (constant power factor), if the real power (P) is zero (<0.0001), then we now instead treat RefFlag = 0 (constant Q). This was done because the initial power factor does not make any sense when P = 0.

March 26, 2018

Features and Improvements

  • GIC: Added support for the TPL-007.1 geomagnetic scaling function
  • Transient Stability: Added AC1C transient Stability Model
  • Transient Stability: Added AC2C transient Stability Model
  • Transient Stability: Added AC3C transient Stability Model
  • Transient Stability: Added AC4C transient Stability Model
  • Transient Stability: Added AC6C transient Stability Model
  • Transient Stability: Added the ability to specify the TSDistGenMVABase with a Load, LoadModelGroup, Bus, Owner, Zone or Area. The MVABase then assumed for the Load Distributed Generation model will be the TSDistGenMVABase associated with the object from which the Load is inheriting it's model. Thus if the Owner object has a Load Distributed Gen model, the Owner object's TSDistGenMVABase will be used. The exception to this is that any Load object that has a TSDistGenMVABase specified will automatically use that MVABase regardless of where the model is inherited from.
  • Transient Stability: Added fields on a Bus, Area, Zone and Owner object to show the presently assigned Load Distributed Generation model name.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed an access violation error caused when calling the new ObjectFieldsInputDialog() script command.
    • File Formats: When writing the SEQ data, if a tertiary winding was not specified for a three-winding transformer an error would occur. This has been fixed.
    • GIC: Fixed column headers for Branch fields "Low R Per Distance" and "Custom DC Resistance" which were interchanged.
    • GIC: Fixed bug in writing *.gic files and adding more digits for the transformer winding resistance output.
    • Integrated Topology Processing (ITP): The interaction of breaker configurations and generators on remote regulation could cause power flow numerical difficulties. Checks have been added to fix these numerical problems.
    • Oneline Diagrams: This fixes the access violation that occurs when using Find Areva Oneline in floating windows mode when the oneline viewer isn't open.
    • Power Flow Solution: PowerWorld performs a remote regulation viability check with generator objects and does not attempt to regulate a voltage if it is impossible to do so. This check has been expanded to include continuous switched shunts and SVCs.
    • PV and QV Curve (PVQV) Tool: "Maximum Transfer" will be reported as the critical scenario even if the step size has been reduced because the transfer ramping fails in the base case when studying a contingency that failed to solve. Previously, this was always being reported as "Reached Nose in Base Case".
    • PV and QV Curve (PVQV) Tool: The "Reached Nose in Base Case" critical scenario can be encountered if the transfer ramping in the base case fails AFTER a contingency has failed to solve and the analysis is being done on this failed contingency. This scenario should only result if the solution continues to fail due to base case ramping and the contingency does not fail. As soon as the contingency fails during this process this result is no longer valid. This has been fixed so that this result will not be reported if the contingency fails.
    • Transient Stability: After loading a REPC_A or REPC_B model it was possible for an access violation to occur when closing the case or deleting objects references by the REPC_A/REPC_B model. This has been fixed.
    • Transient Stability: Fixed bug that could occur when reading a DYD record which had an ID specified as a blank by using consecutive "" characters.
    • Transient Stability: During initialization OEL1 objects were indicating that they were resetting. This wasn't impacting the simulation but was confusing and has been removed.
    • User Interface Dialogs: Added option to abort multiple TLR sensitivity calculation on error. Previously, the error message was shown with an "Ok" button, forcing the user to click ok for each error. If there were many errors, this could be time consuming.

March 16, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Remove FilterPre from the list of required fields for a Filter object. Assume a value of NO if not present.
  • Auxiliary Files (SCRIPT and DATA Sections): On the Auxiliary File Export Format Description dialog, when choosing to Create Format for Complete Case and choosing "Complete Model", the dialog that appears allows you to choose which parts of the model to export. There is now a new check box on this dialog that allows you to specify for the Network Model portion to "(Split commonly changed fields)". Checking this new box will split up fields for some objects into 2 data sections: a section with fields that normally do not change and a second section with fields that commonly do change. This mimics what occurs when exporting data from the Present Topological Differences from Base Case tool.
  • Transient Stability: The swing equation for synchronous machines is 0.5/H*[(Pmech - Dw)/(1+w) - Telec]. In the result reporting for Simulator, the the accelerating power was being reported as Pmech - (1+w)*Telec and thus did not include the impact of the damping term D. For the vast majority of model the D term should be zero, however if D is not zero, then we will now report the accelerating power as Pmech - Dw - (1+w)*Telec instead.
  • Transient Stability: Added the DC4C exciter model
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Added messages in the log when reading Condition or ModelConditionCondition objects from an AUX file which have an invalid ConditionType specified for the ObjectField.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug with the CalculateTLR script command that would produce an error if exactly 6 parameters were passed.
    • Oneline Diagrams: When showing the ThumbNail View on a oneline diagram, the selecting of any text-based fields on the main portion of the oneline may not working properly. If the zoom level of the ThumbNail was such that text would not be drawn inside the ThumbNail then the text could not be selected on the main portion of the oneline. This has been fixed.
    • PV and QV Curve (PVQV) Tool: When saving PV results to file and the base case is critical because of the Maximum Transfer being reached, the message about the Newly Critical scenario just said "base case." This indicates that the base case could not be solved rather than the scenario being critical because of the Maximum Transfer being reached. This has been fixed and the description of the scenario will now say "base case (Maximum Transfer)."
    • PV and QV Curve (PVQV) Tool: Fixed a rare infinite loop problem in which the PV tool could keep repeating the same transfer level over and over again. This would occur if the step size was reduced below the minimum step size because of specifying a maximum transfer level at which to stop the analysis AND a scenario would not solve at this step size.
    • User Interface Dialogs: Fixed a bug where renumbering areas, zones, or balancing authorities if the area contained switched shunts that were on continuous or SVC control. This would cause weird anomalies where areas/zones that were renumbered were appearing as if they were not empty.

March 8, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): There are several ObjectTypes that are contained inside other ObjectTypes. For instance a ModelFilterCondition is contained by a ModelFilter. For many of these ObjectTypes it is convenient when loading an AUX file, to create the container object if it does not already exist, so Simulator automatically does this. However, it was not clear this was occurring to the user, so red warning messages have been added to the log to alert the user this is occurring. Examples of this include the following listed by "ContainerType"\"subtype"
    Filter\Condition
    ModelCondition\ModelConditionCondition
    ModelFilter\ModelFilterCondition
    Interface\InterfaceElement
    Contingency\ContingencyElement
    CTGElementBlock\CTGElementBlockElement
    RemedialAction\RemedialActionElement
    InjectionGroup\PartPoint
    TSContingency\TSContingencyElement
    TSPlayIn\TSPlayInSignal
    TSPlayIn\TSPlayInInfo
  • Case Information Displays: added concise variable names for Superbus and Subnet objects
  • PV and QV Curve (PVQV) Tool: Added concise variable names for PVPlotSeries, PVSubPlot, PVPlotVertAxisGroup, and PVPlot objects
  • Transient Stability: Added additional concise variable names for transient stability models.
    Added concise variable names for following objecttypes TSPlotSeries, TSSubPlot, TSPlotVertAxisGroup, TSPlot, TSLimitMonitor, and Transient_Options.
  • Bug Fixes

    • Case Information Displays: Recent patch after Feb 26 cause the list of User-Defined Case Information displays in the Model Explorer to not work properly. This is now fixed.
    • Contingency Analysis: When using a RemedialActionElements with more than 2 TimeDelays thresholds, coupled with actions the called for opening a branch that was already open, it was possible for the contingency solution process to stop prematurely. This odd situation has been fixed.
    • Distributed Computation: Distributed Transient Stability set to store results to the hard drive were doing so in the case directory rather than in the specified storage directory.
    • Transient Stability: Fixed an error with handling of relaying time if a simulation was run for more than 35 minutes. An integer overflow was occurring because this exceeded more than 2,147,483,648 microseconds. The relays can now handle simulations longer than this.
    • Transient Stability: Adding AUX file support for several Transient_Options fields that previously could not be editted via an AUX file. These fields now have the following concise variablenames: GRNL_Interactive, MOD_FreqInitFromPlayIn, MOD_GICInclude, MOD_GICTimeDelay, MOD_MotorW, MOD_SatSEOneZero, MOD_UndocPILimits

March 2, 2018

Features and Improvements

  • Contingency Analysis Tool: While the contingency dialog was open, when loading an AUX file from somewhere other than the Load button on that dialog, the various edit boxes and check boxes on the contingency dialog the show the contingency options would not always update. This has been fixed so that regardless of how the AUX file is loaded the edit boxes and check boxes will update immediately.
  • Contingency Analysis Tool: Updated the column headings and descriptions of several CTG_Options fields so that when these options are shown in the CTG_Options_Value tables in a case information display more descriptive headings and descriptions are shown. This effects 3 options related to Island Limit Monitoring and 3 options related to storing contingency results to the hard drive.
  • Bug Fixes

    • Integrated Topology Processing (ITP): The Convert to Device Contingencies option was not working correctly to identify devices that are affected by breaker contingencies. This has been fixed.

February 26, 2018

Features and Improvements

  • Bus View and Substation View Onelines: When using the Bus View option to "Show Serial Buses" on a Full Topology Mode, Simulator previously would bias a series of branches to show the non-switching devices most prominently. This was so that Transmission Lines, Transformers, Series Caps/Reactors, and such would appear larger and more prominent. If such a device was not in the series of buses then the first device was always shown. This has been modified so that within a series of switching devices we also bias to show either Breakers or Load Break Disconnects as the prominent device. This makes the breakers and load break disconnects appear more prominently than the plain disconnect switches.
  • Case Information Displays: Custom Expressions can now reference any model field. Previously only Model Expressions could be accessed in addition to fields for the particular expression object type.
  • Case Information Displays: When specifying variables in the Custom Expression dialog, there are now variable type choices of Field, Model Field, Model Expression, and Model String Expression. Model Expressions and Model String Expressions are special entries in an attempt to support older functionality of the dialog when only Model Expressions were available. Specifying Model Fields and Model String Expression as a variable type will not be supported in previous patch releases in Simulator and will become unlinked Model Expressions when loaded into earlier patch releases.
  • Oneline Diagrams: Added right-click options to a oneline to automatically "Open Google Maps". This will automatically open google maps at the “1000m” zoom level and also with it set to show the satellite view. The syntax used is
    https://www.google.com/maps/@40.0902082,-88.2392787,386m/data=!3m1!1e3
  • Transient Stability: When reading and writing a DYD file added ability to translate the distrel/zonedef/blindef models into a DistRelay model.
  • Transient Stability: modified reading of LOCTI record from DYD file so that any parameter after Tm1 can be omitted and a value of zero will be assumed for the parameter
  • Transient Stability: Modified reading the TIOCRS record from DYD file so that any paramter after A can be omitted and a value of zero will be assumed for the parameter
  • Transient Stability: added ability to read/write the CHVDC2 model to and from the DYD file.
  • Transient Stability: Added support for the Exciter models DC1C
  • Transient Stability: Added support for the Exciter models DC2C
  • Transient Stability: Added support for switched shunt model mss1
  • Transient Stability: Added support for switched shunt model mss2
  • Bug Fixes

    • Case Information Displays: Fixed a bug with Custom Expressions that referenced Model Expressions that were set to be evaluated in the contingency reference state when used as part of contingency processing. The Model Expressions were only be evaluated in the current contingency state.
    • Case Information Displays: Pasting a participation point from Excel into the participation point case information display associated with participation points for a particular injection group will now work the same as pasting into the case information display for all participation points for all injection groups. Old functionality wouldn't always allow you to paste into this case info unless you were using the correct set of key fields. Now any set of valid key fields can be used.
    • Scheduled Actions: Fixed an access violation that would occur when right-clicking on a Scheduled Action to open the local menu. This error would occur if the Device was not specified.
    • Scheduled Actions: Fixed an access violation that could occur if trying to find a Scheduled Action that hasn't properly been assigned to a Scheduled Outage. This would mostly occur when trying to create or identify a Scheduled Action through auxiliary files or SimAuto calls.
    • Transient Stability: More clean up of features for auto-inserting distance relays.
    • Transient Stability: Added fix to make critical clearing time command consistent with the dialog. Previously there was no option to clear the fault or open the line (as there is with the dialog). The an optional parameter was added so that by specifying 'O' or 'OPEN' the user can tell the command to open both ends of the line. By default the fault is still cleared.

February 15, 2018

Features and Improvements

  • File Formats: When loading in a PTI RAW files that have been exported from other software such as an EMS system, we have found exported voltages around three-winding transformer can be highly suspicious resulting in very large initial mismatches. This occurs when one or more terminals of a three-winding transformer is radial and not connected to anything that is online. In these situations the star bus and the radial terminal can have per unit voltage magnitudes and angles in the RAW file that are not consistent with the rest of the RAW file. This has been fixed by detecting these situations and assigning a more reasonable voltage and angle for these buses based on the impedances and voltages around them.
  • Bug Fixes

    • Case Information Displays: When performing Column Metrics on special matrix grids (such as the Jacobian or Y-bus matrix), the digits and decimals of the case information display could be incorrectly changed to 32 and 16. This has been fixed.
    • Oneline Diagrams: Fixed a bug in the 64-bit version of Simulator where part of the No Data portion of the contour was not being drawn in.
    • Scheduled Actions: Added "Allow Active" field of Scheduled Actions objects to storage in the PWB file.
    • Transient Stability: Cleaning up the the features for auto inserting Distance Relays.

February 14, 2018

Features and Improvements

  • Integrated Topology Processing (ITP): Renaming the option "Find and open Areva Substation Oneline..." to "Find and open Areva/Allstom Oneline...". This is to make it more general and accurate when applying this option to opening path onelines from the interface definition table
  • Integrated Topology Processing (ITP): Adding the ability to be able to open Areva path overview onelines.
  • Bug Fixes

    • Difference Case Tool: When using the Difference Case tool, any injection group participation points that are not linked will not be included in the comparison. They will not show up in the New, Removed, or Both lists.
    • Integrated Topology Processing (ITP): When reading Areva DDL files, fixed potential error in reading file depending on the placement of parenthesis.
    • Oneline Diagrams: Fixing an issue with the automatic closure of onelines once the max open oneline threshold has been reached so that onelines open within the Oneline Viewer that are closed also close the tab that they inhabited.

February 13, 2018

Features and Improvements

  • Transient Stability: When reading a DYD file, modified parsing of the EWTGFC model so that the last 7 parameters are optional and if omitted will assume the following values: Xc=0, Kqd-0, Tlpqd=0, Xdq=0, Vermn=-0.1, Vermx=0.1, Vfrz=0.7.
  • Transient Stability: When reading a DYD file, modified parsing of the LSDT2 model to allow as few as 5 input parameters to be specified with all subsequent parameters assumed as 0.
  • Transient Stability: When reading a REEC_B record from a DYD file we expect to see 30 input parameters after the colon. This record does not support the mva=12.34 syntax as other records sometimes do, however sometimes we see DYD records which start with the mva=12.34 syntax followed by 29 parameters. In this situation it is reasonable to assume that this first parameter should have instead just been 12.34. We have added special processing of the REEC_B record to support this with a warning message written to the log to indicate this has been assumed. Previously we would have just ignored this record completely and reported an error.
  • Transient Stability: REPC_A and REPC_B models would spit out validation errors when they were configured to measure a branch P, Q, or I and no branch was specified on which to perform this measurement. PowerWorld's hope was that by making this an error which prevented the running of transient stability, this would force the input data to be updated over time, however after a few years it has become clear that this error just confuses folks and the input data has not been updated. We have modified it so that this is now a warning and indicates to the user that all input of IBranch, QBranch, and PBranch will be assumed to be zero until the data is updated.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Slightly modified how the SendToExcel script command sets up a connection to Excel to make it less likely to get a connection and then have Windows subsequently close that connection resulting a Window COM error. Note that it remains dangerous to make repeated called to the SendToExcel script command as this sets up Window COM timing issues with opening and closing Excel in the background. It would be better to use a direct COM connection to Excel that the user manages instead.
    • Difference Case Tool: Unlinked participation factors in an injection group could cause "Duplicate not found" errors when using the Difference Case tool to compare cases. This has been fixed.
    • Oneline Diagrams: When choosing to recalculate the Contour from the toolbar, sometimes as access violation would occur. This has been fixed.
    • Scheduled Actions: When returning actions by using normal status, check to see if the action is active by checking the resolution window if one is in place. Previously we had been ignoring this and returning the action as long as the view time was outside of the time of the action.

February 12, 2018

Features and Improvements

  • Case Information Displays: Added an explicit column for the Island records for "Number". This show the internally assigned Number of each island shown in the user interface. This number is automatically recalculated every time the topology of the system is evaluated. This number matches the number shown on various other tables such as Bus, Gen, etc. which show the island in which a device is contained.
  • Bug Fixes

    • Contingency Analysis: When viewing contingency results by element and comparing contingency results, the summary information about the comparison was not always correct. This has been fixed.
    • General: Fixing an issue that could cause the program to terminate immediately upon startup with the error, "Couldn't start licensing. Terminating immediately."

February 7, 2018

Bug Fixes

  • Oneline Diagrams: Fixing an access violation that could occur when right clicking on a substation display object on a oneline.
  • Oneline Diagrams: Fixing an issue where clicking on a link to another Areva based oneline wasn't doing a search based on where the originating oneline is stored. This was the original behavior.
  • Oneline Diagrams: Fixing a situation where the oneline viewer wouldn't show the file listing within the default folder upon opening.
  • Power Flow Solution: Fixed a bug where voltages were not being updated correctly for the bus that is being reconnected when closing breakers when using the option to "Close Breakers to Energize Switched Shunts." This could result in a failed power flow solution.

February 6, 2018

Features and Improvements

  • Transient Stability: Added the ability to read and implement the LSDT3A model which uses a separate PickupValue as compared to the Setpoint value.
  • Transient Stability: Added storage of result of the Vmin and Vmax values to the DER_A model
  • Bug Fixes

    • Transient Stability: Fixed the under and over frequency tripping of the DER_A machine model so that it does not create a spike in the frequency calculation after the machine trips.
    • Transient Stability: Modified the LOCTI model so that when reading a DYD if the parameter t3trip is not specified a value of 0 is assumed. This is appropriate for this model.

February 2, 2018

Features and Improvements

  • Case Information Displays: Modified how CalculatedField objects work in the user interface dialog when they are very simple and refer to another Advanced Filter by reference.
  • Transient Stability: Added support for the governor model h6e that represents a Hydro Turbine with an American Governor Company Controller.
  • Bug Fixes

    • File Formats: For Version 20 patches on 1/25/2018 and 1/30/2018, there was an error in save backwards to a Version 19 PWB file which make it impossible to read this Version 19 PWB back into either Version 19 or 20. A fix has been added so that we can properly read this PWB file back in and so that we write future version 19 PWB files that do not have this problem.
    • Transient Stability: Fixed bug in bringing up the case information display showing all the results in a particular plot. An access violation was introduced in a recent patch which is now fixed.
    • Transient Stability: Modified DER_A voltage tripping to compare times rounded to the nears microsecond when using Tlv0, Tlv1, Thv0, and Thv1. This makes timing more consistent.
    • User Interface Dialogs: When changing the Filter Object Type on the Advanced Filter Dialog (or inside the Calculated Field dialog), the the list of fields for the field-to-field comparison were not being updated on the dialog immediately. The same was true for the list of filters if you had chosen to "Use Another Filter" as one of the conditions. This would update as soon as you changed the condition field. It will now update immediately however.
    • User Interface Dialogs: Modified the string that appears describing some more obscure object type when using the find/choose dialog. These include the InterfaceElement, ContingencyElement, InterfaceElement, PartPoint, ModelCondition, ModelConditionCondition, ModelFilter, ModelFilterCondition, Condition, and Filter. This was a cosmetic change only that would most commonly be noticed on the Dependency Explorer DialogResizing

January 30, 2018

Features and Improvements

  • PV and QV Curve (PVQV) Tool: Added Maximum Transfer as a critical reason with PV results. This can only appear with the base case scenario. This will appear if the "Stop when transfer exceeds" transfer level is met. This option would always cause the PV analysis to stop, but there was no indication with the PV results object that this has occurred. A message appears on the dialog, but this couldn't be determined by just looking at the results.
  • User Interface Dialogs: Added a button to the Geography tab of the Substation dialog which copies the Lat/Long information to the system clipboard.
    Also added this feature to the menu when right-clicking on a substation object on a oneline diagram.

January 25, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added new optional parameter to ZeroOutMismatches script command. Specify ZeroOutMisatches(Load); to indicate that fake loads should be created to zero out the mismatches. The default behavior is that ShuntG and ShuntB will be changed. Added right-click option to the mismatch table to do the same.
  • Case Information Displays: When using the special syntax of & followed by the name of a Model Expression to specify the value of a field in script commands, Model String Expressions can now be specified as well. Model Expressions and Model String Expressions must have unique names between them so no additional syntax is necessary. When the & syntax is found, Simulator will first look for a Model Expression with the specified name and if none is found Model String Expressions will be searched.
  • GIC: (i) GIC Hotspot can now be modeled as a rectangle (as compared to a square earlier)
    (ii) GIC geographic earth resistivity regions now have an additional field called HotSpotScalar, in addition to the Scalar. This is to model the supplemental event beta_s, as per NERC documents
    (iii) Added option to choose between HotSpotScalar vs. Scalar for points inside a hotspot.
    (iv) Added GICGeographicRegionScalarCustom:1 for substations, which overrides looking up the region's hotspot scalar. Similar to GICGeographicRegionScalarCustom:0
    (iv) Modified GIC calculation to reflect the use of HotSpotScalar, if chosen.
    (v) No read/write support YET HotSpotScalar in PSSE GIC files.
  • Oneline Diagrams: Adding the ability to open Areva substation onelines from MTDC bus, converter and line lists; three-winding transformers; interface elements; substations; superbuses; subnets and scheduled actions lists.
  • Optimal Power Flow (OPF): Updated column headers for OPFSolutionSummary object type.
  • Transient Stability: Added ability to load a OTGD file that represent transient stability contingencies.
  • Bug Fixes

    • Oneline Diagrams: Fixing an issue where oneline links that executed scripts didn't actually execute the scripts if they were invoked within the Oneline Viewer.

January 19, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added the ability to use @MODELFIELD syntax for the following options:
    Transient_Options: ExpDirectory
    PVCurve_Options: PVCOutFile, PVCQVOptionsFile, PVCStoreStatesWhere
    QVCurve_Options: QVOutputDir
    CTG_Options: CTGPostSolAuxFile, PostPostAuxFile, CTGResultStorageFile:1
    Sim_Environment_Options: SEOSpecifiedAUXFile:0, SEOSpecifiedAUXFile:1, SEOSpecifiedAUXFile:2
    MessLog_Options: LogAutoFileName
  • Bug Fixes

    • Power Flow Solution: The power flow solution option to prevent controller oscillations when applied to a switched shunt that was either an svsmo1 or svsmo3 SVC was being applied inconsistently. It will now properly turn the SVC off control if it is oscillating.

January 18, 2018

Features and Improvements

  • File Formats: Fixed another issue with multi-terminal dc line names when writing to a RAW file. When the name is blank the number of the MTDC will be written instead. In this instance, the name was not being enclosed in single quotes, but his has now been fixed.

January 17, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added three additional optional parameters to the end of SendToExcel
    ClearExisting: Optional with default = YES. Set to NO to indicate that the existing worksheet should not be cleared before pasting in the information being sent
    RowShift: Optional with default = 0. Set to a positive integer to indicate a shift downwards by a number of rows
    ColShift: Optional with default = 0. Set to a positive integer to indicate a shift rightward by a number of columns
  • Difference Case Tool: Modified the Present Topological Differences from Base Case tool so that when choose to Save the differences of the Complete Model to an AUX file, the user may now define an AUX Export Format Description object indicating which objects and field lists to use for the export. This appears on the confirmation dialog for exporting the AUX file with the differences.
  • File Formats: Added message to the log when reading hdbexport files and the option to translate the DC system into multi-terminal DC systems is set to Always or Prompt and no DCLN records exist in the file. DC lines cannot be created if DCLN records do not exist.
  • Help: Moved the "Auxiliary File Format PDF" and the "Contingency and RAS Definition PDF" to be contained inside of PowerWorld's public help website.
  • PV and QV Curve (PVQV) Tool: Choosing to archive system states to file will now work when using the Reverse Transfer option with the PV tool and a scenario requires a reverse transfer in order to solve. The states that are stored behave a little differently than when doing the normal forward transfer. Keep in mind that only the contingencies that failed during the 0 transfer will be studied using a reverse transfer.
    (1) When choosing to "save only the base case for each critical contingency" the base case state will be saved at any reverse transfer level at which a contingency solved. This is different than how the states are saved during the forward transfer because then the base case state will only be saved at the critical transfer level, i.e. the highest transfer level at which a contingency will solve.
    (2) When choosing to "save all states" both the base case state and the contingency state will be saved at any reverse transfer level at which a contingency solved. This is the same as how the states are saved during the forward transfer.
  • Bug Fixes

    • Contingency Analysis: Fixed error that could occur when reading in a ViolationCTG object which did not have the fields for Limit or Value specified (normally you wouldn't do this, but it should cause an error anyway).
    • Contingency Analysis: Fixed a related error when saving ViolationCTG objects to an AUX filed for island related violations. They were not properly storing the 4 extra fields associated with islands showing the amount of generator MW, load MW, Bus count, and Superbus count.
    • File Formats: Fixed several issues with multi-terminal dc line names when reading from EPC files and writing to RAW files.
      (1) When loading from EPC files we had not been stripping the double quotes around the names of dc line objects and data maintainers. This has been fixed.
      (2) Because we had not been stripping the quotes when loading EPC files, multi-terminal dc lines could end up with names of " " saved in the PWB file. When loading from a PWB file these quotes will now be stripped so that the name of the multi-terminal dc line will be blank.
      (3) When saving to RAW files, writing the name of a multi-terminal dc line as '" "' was causing bugs when trying to load that RAW file back into Simulator. The corrections listed above should prevent the names from ever being set as " ". When writing to a RAW file if the multi-terminal dc line name is blank the number of the MTDC will be written instead.
    • File Formats: Fixed a List Out of Bounds error that could occur when appending an EPC file to an existing case. The problem was encountered when setting the owners for the dummy buses in multi-section lines.
    • GIC: Fixed a bug with "No Resistivity Scaling" in GIC Dialog. Now when this option is selected, the backend knows to use scaling of 1 by default, even if the Substation has GeographicRegion or GeographicRegionScalar or GeographicRegionScalarCustom.
    • Simulator Automation Server (SimAuto): Modified SimAuto so that it will never use the AutoSave PWB file option. This doesn't make sense in the context of SimAuto.
    • Simulator Automation Server (SimAuto): When using the SaveCase() script command or when calling the SimAuto command SaveCase, if you were trying to write a file to a directory that Windows was not configured to you write access to, then Simulator would show an error dialog. In these situations we do not want an error dialog to appear, but instead the error is handled and passed back to SimAuto for the user to interpret as appropriate.

January 11, 2018

Features and Improvements

  • Contingency Analysis Tool: Added support for several new VSCDCLine contingency actions that mimic the features available with the two-terminal DC line
    OPEN
    CLOSE 20 MW
    SETTO 40 %
    SETTO 20 MW
    CHANGEBY -60 %
    CHANGEBY -30 MW
    SETTO 5 OHMS
  • Contingency Analysis Tool: Added translation of the VSC DC Line OPEN contingency actions to a BLOCK VSCDC in the *.con file.

January 9, 2018

Features and Improvements

  • Contingency Analysis Tool: Added ability to write out two additional Contingency action types to a PTI CON file
    1. BLOCK TWOTERMDC 'name' // Opens the DC line
    2. SET TWOTERMDC 'name' to 12.34 MW
    3. SET TWOTERMDC 'name' to 12.34 MW
  • General: Added the ability in an interface to include a Generator OPEN or a Load OPEN element. This has been integrated in the calculation of the AC Power Flow Solution, Linearized DC Power Flow Solution, the PTDF calculation, and the sensitivities and flows needed to perform an OPF solution.
  • Bug Fixes

    • Power Flow Solution: In the patch on 1/8/18 the following change was made: When using the option to Check Generator Mvar Limits Immediately, generators will only be allowed to hit limits for the first two voltage control loop iterations. After that they will only be allowed to back off limits.
      A bug was introduced with this that would ALWAYS set the option to back off immediately instead of just setting this if the option to check immediately was in use. This has been fixed.
    • PV and QV Curve (PVQV) Tool: When the source or sink is maxed when ramping in the PV base case and the system state is left in the last state, the Present Nominal Shift value shown on the dialog edit box was not reflecting the actual transfer in the system state. This has been fixed.

January 8, 2018

Features and Improvements

  • Difference Case Tool: When showing some values in difference flows we show the Present Value followed by a | character followed by the Base Value such as " 103.45| 206.45". Depending on how wide the column is on the display however the text may have the portion of the string with the | character truncated. If the user can not see the | character it makes is confusing as to whether the value has changed or not. To avoid this confusion, we will now show the background color of cells shown in difference flows that contain a | character with a slightly different background color to indicate the value has changed.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Changed the tolerance for the injection group ramping options for Merit Order and Merit Order Close to be consistent with tolerances used during ATC ramping. An infinite loop could result during ramping while using one of these methods and also using one of the iterated ATC methods if the tolerances are not consistent.
    • Power Flow Solution: Fixed power flow solution when using optimal multiplier. In most situations the optimal multiplier was not being used even when the option to use it was in effect. This could cause the power flow to produce strange results, such as very high voltages, especially when doing PV solutions near the nose of the curve.
    • Power Flow Solution: When using the option to Check Generator Mvar Limits Immediately, generators will only be allowed to hit limits for the first two voltage control loop iterations. After that they will only be allowed to back off limits.

January 4, 2018

Features and Improvements

  • Transient Stability: Added ability to right-click on the transient stability event case information display and show the dialog associated with the power system object refered to by this action.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Updated SetData script command to avoid erroring out when an object cannot be found. This was causing problems for users loading data with a SetData command over multiple cases where some objects may be missing or renumbered. An error will still be generated if the needed fields are not specified, or if there is a syntax error.
    • Power Flow Solution: Fixed a bug that would cause the fast decoupled solution not to solve correctly if not evaluating the power flow solution for each island.
    • Transient Stability: Added an extra message to relay when they are in Monitor/Alarm mode to say when they are supposed to open a relay after a delay. This was not showing and some user were thinking that the initiate trip message was the trip time of the relay.
    • Transient Stability: Modified interaction with transient stability event dialog when entering information on the dialog and then clicking Insert (at the top of the dialog). Previously clicking Insert would create a new action, but clear out some of the settings on the dialog (clicking OK worked fine). This has been modified so that clicking Insert does not clear any settings on the dialog.

December 28, 2017

Features and Improvements

  • Oneline Diagrams: Adding GDV arrow objects for showing vectors.
  • Transient Stability: Added ability to delete all jpgs in the TS contour toolbar subdirectory. This is just a button on the dialog used to specify saving the TS contour images.
  • Bug Fixes

    • User Interface Dialogs: Fixed a bug that was causing Simulator to freeze when opening the limit monitoring settings. The problem was caused by an infinite loop if an interface contained a multi-section line object in it.

December 22, 2017

Features and Improvements

  • Transient Stability: Added VFE of ESAC8B_GE into the State Other Fields.

December 21, 2017

Features and Improvements

  • Oneline Diagrams: Adding the ability to open Areva substation onelines from the right click menu on string grid displays. Also can search for onelines in the Oneline Viewer.
  • Oneline Diagrams: Adding the ability to pan to display objects via the Areva "find" command when loading in a oneline via a oneline link.
  • Oneline Diagrams: Adding the PanAndZoomToObject() oneline script command.
  • Oneline Diagrams: Adding a parameter to OpenOneline() that takes a script command to be executed within the newly opened oneline.
  • Oneline Diagrams: Adding the ability to open the script action form from the oneline so that the user can execute scripts on the oneline display.
  • Oneline Diagrams: Adding multiple click actions on oneline link objects and the ability to manipulate the oneline link object multiple actions through sgfields.
  • Time Step Simulation: Modified TimeDomainOPF so it sets the GIC time value to be the offset time from the start of the time domain simulation.
  • Bug Fixes

    • Oneline Diagrams: Fixed a display bug where copy/pasted transmission lines would not be inserted in the correct location. This only effected
    • Oneline Diagrams: When clicking on the Up/Down arrow next to a switched shunt on the oneline diagram, if the shunt was not set to ControlMode = Fixed, then the up/down arrows would not work. This has been fixed.

December 19, 2017

Features and Improvements

  • Transient Stability: Added new Branch field for storing results called "Minimum Profile Vpu". This field calculates the minimum voltage along the length of the series R and X of a branch. Typically this value is at one of the terminal buses, but it can sometimes end up between the two buses. It is possible for that voltage to approach zero even when both terminals are not zero. This is an indication of the system going out of step. One can monitor this branch field for an indication of the system going out of step.
  • Bug Fixes

    • File Formats: When reading the Areva CTG CSV file, the type POLEW is interpreted the same as POLE meaning that the DC Converter is taken out of service. This was working fine, but an incorrect message log warning was being written regarding saying the POLEW was an "Unidentified type". That error message was wrong and has been removed.
    • Optimal Power Flow (OPF): In a very rare situation, fixed the evaluation of whether to monitor an interface that contained a multi-section line object. If the only object in the interface was a multi-section line and the monitored end of the multi-section line ended up begin a branch that was not going to be monitored we would then not monitor the entire interface. The particular example we had was the first branch of a multi-section line was a bypassed series cap and we never monitored bypassed elements. This has been fixed so that as long as at least one branch within the multi-section line is monitored we will consider the multi-section line to be monitored.
    • Transient Stability: When right clicking on Validation Errors, Warnings, and Information Messages and choosing Show Dialog, the dialog was only appearing for messages related to generator objects. This has been fixed so that the dialog will appear for messages related to loads, shunts, branches and other objects as well.

December 14, 2017

Features and Improvements

  • General: Model String Expressions can now reference other Model String Expressions.
  • User Interface Dialogs: When using the Save to Aux button on bus, switched shunt, generator, branch, line shunt, and load dialogs save using fields that are the same as default Network Model fields with the Aux Export Description. When saving switched shunts use appropriate fields if the shunt is allowed to be on control, i.e. control mode <> Bus Shunt. When saving transformers save using appropriate transformer control fields.
  • User Interface Dialogs: changed the hints that appear for the MVA Convergence Tolerance and the AGC tolerance to reference the fields that are in the unit of MVA (instead of the old fields which were in units of per unit)
  • Bug Fixes

    • File Formats: When reading in an Areva CSV hdbexport file with an unrealistic DC line voltage schedule, we automatically modify the minimum transformer tap ratios to ensure that the initial condition can be obtained. This was not properly working under some circumstances for inverters that were at these limits in the initial case. This has been fixed.
    • Transient Stability: When reading an REPC_A model from an AUX file and using the measured branch object, the flow measurement bus of the extra object was not being properly read. This has been fixed.
    • Transient Stability: When reading in particular SVCALS shunt model from a user-written DYR model there was an error with reading the parameters. This has been fixed.

December 11, 2017

Features and Improvements

  • GIC: Adding ability to show GIC results in time step simulation. Also fixed bug with time step timepoint changes.
  • Time Step Simulation: Updated time step summary to show load/gen/shunt results as opposed to input.
  • Transient Stability: Added support for the newer Bradley Governor for Chugach (HGBLEM)
  • Transient Stability: Added ABBSVC1 Switched Shunt transient stability model
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: Fixed a bug that might cause RAS to not implement correctly during the full CTG solution during ATC analysis if the RAS involved Model Conditions using the Evaluate in CTG Ref State or Disable if True in CTG Ref State option.
    • Available Transfer Capability (ATC) Tool: Added FULL_RESERVE_LIMIT as Iteratively Found string for ATC results that end up hitting a reserve limit when using the full CTG solution method. There is also a companion transfer limit that indicates if the source or sink hits the reserve limit and this limit has always existed. Changing the iteratively found string makes it easier to determine that the iterations were terminated because of a limit if they end up getting sorted and you don't see the companion limiter right next to the result.
    • Available Transfer Capability (ATC) Tool: When hitting a reserve limit when using the full CTG solution ATC method and the contingency does not solve at the reserve limit transfer level, go ahead and iterate on the contingency if the option to iterate on failed contingencies is in use. Previously, the iterations would stop at this point and just report the transfer level at which the contingency last solved without providing an indication that the contingency failed.
    • Contingency Analysis: Fixed error that could occur opening the Dependency Explorer if any object available for selection in the explorer referenced a calculated field that was not defined.
    • Contingency Analysis: Fixed a bug where a MON file would hang when read if the last character of the last line of the file was the EOF character instead of a CR or LF. Previously we assumed that every line would have a CR or LF at the end, and that the EOF marker would be on its own line after the last line of text.
    • Contingency Analysis: When solving the DC transmission network equations during the AC power flow solution the same tolerance was being used for the DC equations as for the AC equations. It's important in some situations to ensure that the DC equations are solved more precisely so that the evaluation of the AC power flow mismatch is not off. The tolerance of the DC equations is now always 0.5*AC tolerance.
    • General: Changing the licensing to be more robust in the face of high CPU contention (greatly reducing the propensity for "Pipe read timed out" and thus licensing errors) and also so that the main program terminates more quickly.
    • PV and QV Curve (PVQV) Tool: When using Merit Order dispatch as a contingency action we must set the units dispatched to AGC = NO so that they don't end up moving again during the contingency make-up power calculation (this is correct). However, we were also setting AGC = NO when Merit Order dispatch was used as a ramping method outside of contingency analysis, which was NOT correct. This has been fixed. This would only affect solutions where the AGC status of generators was enforced as part of the injection group using merit order ramping.
    • Transient Stability: Fixed error when a dynamic switched shunt model was assigned to a shunt that was presently out of service in the base case.

December 4, 2017

Bug Fixes

  • General: Changing the licensing to be more robust in the face of high CPU contention (greatly reducing the propensity for "Pipe read timed out" and thus licensing errors) and also so that the main program terminates more quickly.
  • PV and QV Curve (PVQV) Tool: When using Merit Order dispatch as part of PV ramping, generators pariticipating in the ramping were being set to AGC = NO, which prevented them from moving at the next ramping step if they weren't already at their limits. This was only a problem if using the non-default option with injection group ramping to Allow only AGC units to vary. This has been fixed.

December 1, 2017

Features and Improvements

  • Difference Case Tool: Added a button to remove field customizations for all of the difference grids on the topological differences dialog.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When using the SendToExcel script command and OLE error could result if not specifying the name of the worksheet. This has been fixed by assuming a default name based on the object type of the data being sent to Excel if the user doesn't specify a name.
    • Case Information Displays: When using the Close with Breakers option from a case information display or a oneline, it was assumed that only the chosen device should be closed in. It makes more sense to allow other devices to be closed. This is especially important in situations such as a generator connected to a transformer and the breaker is on the high side of the transformer. If we do not allow the transformer to be closed the generator cannot be closed.
    • Contingency Analysis: Made the local menu options for Contingency case information display consistent whether it is displayed in the Model Explorer or on the contingency analysis dialog.
    • Contingency Analysis: Made corrections to properly retain the AGC method in use during a contingency solution with the reference state if a contingency solution is then manually set as the new contingency reference state.
    • File Formats: When writing to an EPC file, added a space between the from bus nominal voltage and the to bus number for breaker records to prevent long bus numbers from running into the from bus nominal voltage.
    • Oneline Diagrams: The small Color Key dialog for the contouring of a oneline can be made transparent. The option to "Remove Transparency from all Windows" however would not remove the transparency from this particular small window. This has been fixed.
    • Transient Stability: Fixed potential error that could occur after showing a group of plots in transient stability and then choosing to show them again.

November 28, 2017

Bug Fixes

  • Power Flow Solution: During case validation when island numbers are set for buses, a stack overflow error could occur when using the 64 bit version of Simulator. This has been fixed.

November 27, 2017

Features and Improvements

  • Difference Case Tool: Added Case Info Customizations for all case information displays used with the Difference Case tool dialog.
  • Oneline Diagrams: Added color map for showing integer values.
  • Transient Stability: Added substation field for average ROCOF.
  • Bug Fixes

    • Transient Stability: When writing switched shunt dynamic model data to a DYR file, Simulator was writing the ID of the shunt. The RAW/DYR formats do not support multiple switched shunts at a single bus and therefore the DYR format should not include the ID. This has been fixed.
    • Transient Stability: PSS1A stabilizer was not working with T6=0. This has been fixed.

November 21, 2017

Bug Fixes

  • File Formats: Fixed error when saving interfaces with unlinked elements to a PWB file. They were not being correctly counted in the number of elements to save but they were still being saved in the file. This would cause an error when loading the file back in. When loading files that have been saved incorrectly it should be possible to recover them by manually intervening where the errors occur on load.
  • Power Flow Solution: When solving island based AGC, MW limits for the system slack bus were not being enforced correctly and this could cause extra MW loop iterations of the overall power flow solution without actually adjusting the island slack within its limits. This has been fixed.
  • Power Flow Solution: When solving areas or super areas on participation factor control, MW limits for the system slack that is part of the area or super area will be enforced if all appropriate MW enforcement options are selected. If the slack happened to be set to a limit but the amount of change was less than the area or super area tolerance, the change would not be redistributed to the rest of the group. Now this change will be redistributed as long as it is greater than 2 times the MVA convergence tolerance. This might help to prevent extra MW loop iterations.
  • Transient Stability: Added a new parameter to DISTRELAY and DISTRELAYITR (FarRelayEnd). Since now the DistRelay determines how to coordinate with another relay by only using the desired branch and the device id there needs to be a mechanism for specifying the coordination the old way. This new parameter is set to 0 (Default) means it will look for the Far Relay Device to be at a different end from this device location end plus the Device id; 1 means it will look for Far Relay Device and only will look for the Device id (The device end will not matter).

November 17, 2017

Bug Fixes

  • Case Information Displays: Fixed an access violation that could occur when flood filling on a case information display.
  • Oneline Diagrams: An access violation could result when loading Display Auxiliary (AXD) files into a oneline containing grouped objects. This has been fixed.
  • Power Flow Solution: When a switched shunt that is part of a Voltage Control Group is oscillating its Control Mode will now be set to Fixed instead of setting Auto Control to NO. If the Voltage Control Group Status is set to FORCEON, the Auto Control field for a switched shunt in that group is ignored. This will result in the shunt oscillating forever. For a shunt to participate in a Voltage Control Group its Control Mode must be discrete, so setting the Control Mode to Fixed will prevent the oscillations. Any switched shunt that is oscillating and is not part of a Voltage Control Group will have its Auto Control set to No.
  • Transient Stability: Added better comments to know which relay is operating or giving transition events during simulation.
  • Transient Stability: Improved the messaging associated with the DistRelay model.
  • Transient Stability: Corrected how the DistRelay determines how to coordinate with another relay.

November 15, 2017

Features and Improvements

  • File Formats: Can now read version 34 RAW files.
  • Scheduled Actions: Added options to the Scheduled Action grid local menu allowing the user to isolate or energize the target device with breakers.
  • Transient Stability: Added VFE of ESAC8b_PTI into the State Other Fields.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When reading an AUX file containing a list of script commands, Simulator will now force windows to process any screen, keyboard, or mouse actions after each script command occurs. This ensures that the message log continues to be updated.
    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug where buses with numbers <= 0 could be read and created from an AUX file. Now buses must have a number > 0, or it will be ignored.
    • Case Information Displays: Fixed behavior of navigation using arrow keys so that it is consistent with Excel.
    • Contingency Analysis: An access violation could occur during contingency analysis when injection group actions using the Best Fit Open scaling option are triggered. This has been fixed.
    • Fault Analysis: Fixed bug auto inserting faults where two buses at the same voltage level with the same name EXCEPT for a space in the middle (i.e. MY BUS and MYBUS) would result in one of the two buses not being included in the fault list. These are now treated as two different buses.
    • File Formats: Fixed bug where reading PWB would crash if a Substation was stored in the PWB file that had a bus in its bus list with a number of 0. A 0 bus number shouldn't happen, but somehow it did.
    • File Formats: When reading an EPC file, fixed a bug that was creating Multi-terminal DC lines without a unique record name.
    • Scheduled Actions: When reading Start/End times in the scheduled action tool, the time format "11/20/2017 12:30" in military time was being interpreted an AM time. This only impacted times between 12:00 - 12:59. This has been fixed.
    • Transient Stability: Fixed a bug that was causing an access violation when saving REECA1 model to a DYR file.
    • Transient Stability: Added device ID to DistRelay messages.
    • Transient Stability: Fixed a bug that was preventing the loading of user defined model DLL files.

November 9, 2017

Features and Improvements

  • Case Information Displays: On the Multi-Terminal DC Line and Two-Terminal DC line case information displays, add the ability to right-click on a selection of devices and choose "Remove Device and Converter to Equivalent Loads". This will add in new load objects which replace the MW and Mvar injections coming from these devices and then delete the DC system device.
  • Scheduled Actions: Added ScheduledActionSetReference script action to save the current system state as the reference state for Scheduled Actions.
  • Scheduled Actions: Added Scheduled Actions tab to dialogs for Gens, Loads, Lines, Switched Shunts, and Interfaces containing a case information display listing the Scheduled Actions that target the selected object. The tab is hidden if there are no Scheduled Actions defined in the case.
  • Transient Stability: Added the ability to rename the Device ID from a relay GUI dialog. It will only rename the Device ID if the new Device ID does not exists. If the Device ID already exists then the following message will appear: A Device ID already exists at from/to end (Line Name). Please Modify that particular (Relay Name)relay.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: Fixed some inconsistencies in the system state when restoring the initial ATC state when using topology processing and the status of breakers has changed between the current state and the initial state.
    • Available Transfer Capability (ATC) Tool: Fixed a bug when using one of the iterated ATC methods and using the option to close breakers to energize switched shunts or using one of the injection group ramping methods that allow breakers to close to include generators in the dispatch. If a breaker ends up being closed by either of these processes during the ramping and the breaker is part of a contingency, the breaker most likely would have been ignored when calculating the LODFs. The LODFs are calculated once at the beginning of the ATC process for speed. When the LODFs are needed for the contingency including the breaker an access violation would have resulted. This has been fixed.
    • File Formats: Fixed bug that could occur when converting the EMS DC System into a DC model consistent with PowerWorld Simulator. If the DCCNV grouped in a POLE record in the EMS hdbexport file were out-of-service AND those DCCNV were connected to different XF records which were also separated from another by switching devices then it was possible for the DC system to be read incorrectly. This was an unusual situation and has been fixed.
    • Power Flow Solution: Fixed potential error in the power flow solution that could occur when a inverter bus hit a firing angle limit while controlling MW.
    • PV and QV Curve (PVQV) Tool: Fixed some inconsistencies in the system state when restoring the initial PV state when using topology processing and the status of breakers has changed between the current state and the initial state.
    • Scheduled Actions: Restructured internal lists of Scheduled Actions and Scheduled Action Groups to improve performance with large sets of schedules.
    • Scheduled Actions: When reverting scheduled actions to normal status and the object being closed is a Breaker, we also close Disconnects that are in series with the Breaker. There have been some cases where Load Break Disconnects are found to be in series with the Breakers being returned to service and these are normally closed. If we do not also close the Load Break Disconnects we cannot return lines to service. Now when returning Breakers to service we will also close any Load Break Disconnects that are normally closed and they are in series with the Breaker. If we are returning a Load Break Disconnect to service as the element that is part of the schedule we will NOT also close Load Break Disconnects that are in series.
    • Time Step Simulation: Corrected the Starting and Ending Time controls so that these can be specified down to seconds rather than only by hour.
    • Transient Stability: Modified documentation of DER_A to make it clear particular parameters can be equal to zero.
    • User Interface Dialogs: On the branch dialog only show the transformer tap and phase shifter fields if the branch is a transformer or phase shifter or these values have been set to something other than defaults of 1 for tap and 0 for phase shift.

November 6, 2017

Bug Fixes

  • Integrated Topology Processing (ITP): When performing the Equivalencing on a full-topology power system model, some errors could occur in the calculation of the equivalent due to numerical precision problems. This has been fixed.
  • Integrated Topology Processing (ITP): In the integrated topology processing, fixed an error that could cause a power flow mismatch in a very rare situation. A dead bus that was radially connected and had a NomG or NomB value but did NOT have any load, gen, or shunt attached would cause the problem.
  • Transient Stability: Fixed initialization of REPC_A and REPC_B when the Ki or Kig values are entered as exactly zero.

November 3, 2017

Features and Improvements

  • Case Information Displays: Prior to this patch, when dynamic formatting was defined for a bus object's case information displays, it was always inherited by the area, zone, and substation objects. These objects would automatically apply the formatting if any bus in the aggregation met the conditions of the dynamic formatting. Previously this inheritance could not be prevented which was reported as a problem by some users. This inheritance has been removed as it is easy enough to define dynamic formatting for area, zone, or substation objects using advanced filtering that applies to a bus object type now.
  • Oneline Diagrams: Fixed an error in patch relase from yesterday related to the new BranchCloseAngleThreshold. It was accidentally preventing the closing of any breaker on a oneline.

November 2, 2017

Features and Improvements

  • Case Information Displays: In Version 20 we added the Quick Filter drop-down directly on the Filter toolbar. As part of doing this we changed the caption of the button for opening the quick filter dialog to "Dialog". This also changed the caption of the button under the Filter drop-down the the Case Information Toolbar to "Dialog" which caused confusion. We have changed the caption under the Filter drop-down back to "Quick Filter..." to be consistent with previous versions.
  • Case Information Displays: The list of secondary filter classes available for objects has continued to grow to provide flexibility. However this has made the Filter drop-down menu on the case information toolbar extremely long as a result. We have organized this drop down menu so that object types are grouped by type such as "Network", "Aggregations", etc... Secondary filter classes that are in the same grouping will continue to appear directly under the filter submenu, but those in a different grouping have been moved inside an additional sub menu.
  • Oneline Diagrams: Added a new field to a Branch object called the "BranchCloseAngleThreshold". Specifying a non-zero value for this field will impact how oneline diagrams behave for this branch. When clicking on the circuit breaker objects on a oneline diagram that represent the status of a particular branch, if the branch is presently OPEN and the angle difference across the branch is greater than the threshold specified, then the oneline diagram will not permit you to close in this branch. This was added to help users perform operating training simulations.
  • Oneline Diagrams: Added ability to include arrows on the generator cost multiplier field.
  • Transient Stability: modified the Transient Stability tab on Load dialog to always show the "Terminal and State Values" tab so that the user knows it's available. Previously this tab would be hidden on the load dialog if the transient stability simulation had not been initialized. Now it will always appear, but if the simulation is not initialized then it will show all empty values.
  • Bug Fixes

    • Distributed Computation: Added a message to the log when all remote SimAuto sessions have finished when running distributed contingency analysis.
    • Sensitivity Calculations: Corrected the warning message that is shown when doing a PTDF calculation from the PTDF dialog with a seller and buyer of injection groups. If either of the injection groups does not have any nonzero participation factors, the error message indicated that both of them did not have any nonzero participation factors. This message has been fixed to show the correct injection group that does not have nonzero participation factors.

October 31, 2017

Bug Fixes

  • Difference Case Tool: Fixed error in ownership filtering of base case objects in the difference case tool.
  • Power Flow Solution: When choosing the Power Flow Solution Advanced Option to "Evaluated Power Flow Solution for Each Island", if the island ends up being short of controllable generation or load hit MW limits, then a dialog will appear indicating "Some islands did not have enough controllable generation or load and are hitting RESERVE LIMITS. Click OK to open the islands case information display in the Model Explorer". This will then open the island case information display which now has the Solved column as a default column which will say "RESERVE LIMITS" for islands that don't have enough control.
  • Simulator Automation Server (SimAuto): Updating RegSimAuto so that it notifies the user that 32-bit RegSimAuto doesn't affect 64 bit registration and vice versa. Also gives more visual feedback that a version of Simulator *is* registered, but not the one that is currently registered by the running RegSimAuto.

October 30, 2017

Features and Improvements

  • Optimal Power Flow (OPF): Added check boxes to the OPF tab of the Area dialog for specify whether to Enforce Branch Limits, Enforce Bus Angles, Enforce Interface Limits, Allow DC Line Control, or Include Marginal Losses.
  • Bug Fixes

    • Contingency Analysis: Fixed 3 bugs related to the Max Loading Field for branches that provides the maximum % contingency loading for a branch over all contingencies.
      (1) When used in the AC solution method it was not correctly calculating the loading based on the contingency rating.
      (2) It is now calculated when using linear contingency methods or solving while in dc power flow mode.
      (3) It will be updated if solving a single contingency and the single contingency loading is greater than any previously stored loading.
    • Contingency Analysis: Fixed an access violation that would occur in the 64 bit version of PowerWorld Simulator when performing the Auto-Insert contingency procedure.
    • Oneline Diagrams: Fixed a very rare bug that could occur when display a Background Rectangle on a oneline diagram and also simultaneously showing the contouring color key. This would cause the background rectangle to be drawn in the incorrect place immediately after contouring a oneline. Subsequent refreshes of the oneline drew correctly however. All of this has been fixed.

October 27, 2017

Features and Improvements

  • Oneline Diagrams: When performing an action by clicking on a oneline link, now automatically invalidate the NWin to force a redraw after doing this.
  • Transient Stability: Modified the interpretation of Direct parameter of the LOCTI, TIOCR1, and TIOCRS over-current models. Previously it only had options 0 and 1 below. Option 2 has been added.
    0 - means no directional element
    1 - means directional element AND Direction will be based upon current leaving the FROM end of the branch
    2 - means directional element AND Direction will be based upon current leaving the TO end of the branch
  • Bug Fixes

    • Transient Stability: Fixed a bug when reading some particular svsmo2 fields from an AUX file or when copy/pasting from a spreadsheet. The fields effected were Tdbd, PLLdelay, Tout, and dbe.
    • Transient Stability: Fixed a bug where setting a fault to single line to ground, and checking the box for the impedance to be created from the sequence data, resulted in an access violation when the transient was run.

October 25, 2017

Features and Improvements

  • User Interface Dialogs: Separating "Save" and "Save To Aux" button on the bus, branch, load, gen, shunt, and lineshunt dialogs. Clicking the Save to AUX will now store the fields specified as part of the built-in "Network Model" Auxiliary File Export Format Description.
  • Bug Fixes

    • Optimal Power Flow (OPF): When running the OPF with a full topology case and using topology processing it was possible to get an out of memory error at the end of the OPF solution. This has been fixed.

October 24, 2017

Bug Fixes

  • Power Flow Solution: When determining how switched shunts should switch when they are part of a control group regulating the same bus, the Var Regulation Sharing parameter determines the order in which shunts should switch. For discrete shunts we switch them in the order of highest to lowest Var Regulation Sharing parameter. We had been NOT been switching any shunts away from zero if they did not have a Var Regulation Sharing parameter greater than 0. Cases loaded from hdbexport files can end up having this parameter set to 0, which was causing shunts that presumably are supposed to move not to move. Because this parameter is defined as an order, the restriction on the Var Regulation Sharing parameter being greater than 0 has been removed when switching discrete shunts. For continuous shunts, we will still not move any shunts unless this parameter is greater than 0.
  • Power Flow Solution: Better handle situation in which the initial base case power flow does not solve for PV analysis. The error messages should be clear now that this is a problem.

October 23, 2017

Features and Improvements

  • General: Optimized the closing of a power system case for cases that included a very large number of of model conditions, model filters, model expression, and/or contingencies. The case will now close much more quickly.
  • Integrated Topology Processing (ITP): Added storage in the Window Registry for the user interface options on the Limit Monitoring Dialog. Previously the following was maintained during a session of PowerWorld Simulator, but after you closed Simulator and reopened it, it was not retained. The options include
    1. The check box status of “Only show the primary bus for each superbus”
    2. The choice under the “Elements to Show”
    3. Which tab you are on the dialog
  • Transient Stability: Added the ability to filter transient result events table from Object type.
  • User Interface Dialogs: Added two new buttons under the Restore> dropdown on the Tools ribbon tab called "Store User State" and "Restore User State". These provide button access to same functionality as available in the script commands StoreState; and RestoreState(USER);
  • Bug Fixes

    • Case Information Displays: 6 new fields for showing the Percent MVA at both the FROM and TO buses based on the A, B, and C MVA limits were added to branch objects in October 2016. There was an error with the PercentMVAATo value (it showed the FROM side percentage) and the PercentMVACFrom value (it showed the TO side percentage). This has been fixed.
    • Difference Case Tool: A nearly identical fix as made in October 11, 2017 regarding changes in the bus' owner. The behavior was the same for changes in the bus' area, zone, or balancing authority as well. Same changes made.
    • Distributed Computation: Adding the Distributed Computation Configuration tool to the installation.
    • Integrated Topology Processing (ITP): Fixed a bug for PV, QV, ATC, and SCOPF tools when using consolidation along with Remedial Actions that were defined as Open with Breakers (or Close with Breakers). The actions were not properly determining which breakers to open or close.
    • Oneline Diagrams: When loading an AUX file that defines a custom menu hierarchy in the Oneline Viewer multiple times, menu ordering will likely become scrambled. The SortIndex field was added to the CustomMenuNode object in order to keep the menu order stable when loading multiple times.
    • PV and QV Curve (PVQV) Tool: Update the Present Nominal Shift box on the PV curve dialog to show the transfer that is in the current system state. Previously, this would most likely show the highest transfer amount that would solve in the base case, which would most likely not be the actual transfer that is in the current system state. This could cause confusion with the user thinking that this is the amount in the system state.
    • PV and QV Curve (PVQV) Tool: On the PV Curve Dialog, updated the caption with the Restore Last Solved State option to show the transfer amount that is in that state.
    • Scheduled Actions: The Selected field was not toggleable for Scheduled Actions objects but should have been. This has been fixed.

October 17, 2017

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): An interface element will meet the area/zone filter if its interface meets the area/zone filter. Previously, an interface element would meet the area/zone filter if its individual device met the area/zone filter. This could cause situations that could re-define an interface if interface elements are missing when this information was loaded from an aux file. It makes more sense to keep all of the interface elements as long as at least one of the elements meets the area/zone filter. An interface will meet the area/zone filter if at least one of its elements meets the area/zone filter. This is the way that area/zone filtering has always worked for interfaces.
  • Auxiliary Files (SCRIPT and DATA Sections): Added ability for Data Maintainer objects to work as a filter on case information displays in a manner similar to Area/Zone/Owner filters. There is a now a global option that indicates if Data Maintainers should be used as a filter, and if this is set then their is a Filter field on each Data Maintainer.
  • Case Information Displays: Added ability for Data Maintainer objects to work as a filter on case information displays in a manner similar to Area/Zone/Owner filters. There is a now a global option that indicates if Data Maintainers should be used as a filter, and if this is set then their is a Filter field on each Data Maintainer.
  • Case Information Displays: Cleaned up the Owner filtering for objects. When using the find dialog on a table if the object found was not presently visible on the case information display because Area/Zone filters were not met, Simulator would automatically change the area/zone filtering to make the object visible. This has now also been done for Owner filtering and the new Data Maintainer filtering.
  • Contingency Analysis Tool: Modified saving contingency analysis settings using DataMaintainers so that they make use of the new "Filter" field for a DataMaintainer instead of using the Selected Field. This is more consistent anyway.
  • Difference Case Tool: Added ability for the list of Removed Substations in the Present Topological Differences from Base Case tool to properly use the Area/Zone/Owner filters. Previously that table did not use those filters.
  • Difference Case Tool: Modified the Base Case Topological Comparisons dialog so that user may use Data Maintainer filters to specify which objects to write out to a file.
  • Difference Case Tool: Added the Area/Zone/Owner filter menu/case info toolbar option to the Removed object tables in the Topological Differences from Base Case dialog. The functionality to filter these tables by area/zone filters had just recently been added so there had previously been no reason to care about them from these tables.
  • Integrated Topology Processing (ITP): When using the close with breakers algorithm on a branch, breakers will be closed even if the branch is only open at one end. The branch is energized, but the goal should be to have it closed completely. Previously, no breakers would be closed if the branch was considered energized. Now if the branch has Derived Status <> Closed we will search for breakers to close. This is done anywhere that the close with breakers algorithm is used.
  • Oneline Diagrams: Updated kml parser to parse PJM lines. This required fixing some things not handled when parsing the lines for coordinates. The PJM files have x,y,z coordinates instead of just x,y. The files do no contain identifiers that can be linked with the case, but at least unlinked lines are now read in.
  • PV and QV Curve (PVQV) Tool: Changed caption on the PV Quantities to Track tab for injection groups from "Groups" to "Injection Groups".
  • Transient Stability: Modified WT3G, WT4G, REG_A, PVD1 type model that have "reactive current management" that prevent high voltages on voltage source converter machine models. Previously if the initial terminal voltage was above the high voltage limit, we would ignore this limit completely. This has been modified so that instead the high voltage limit is set equal to the initial terminal voltage. Indication that this is occuring will appear in the Validation Warnings.
  • Transient Stability: Added a new plant controller named REPC_B100 which is the same as REPC_B but instead of allowing 50 generators to be referenced, you can have 100 generators.
  • Bug Fixes

    • Difference Case Tool: Support ObjectID field with DataMaintainer object. This is needed for generic functionality with the difference case tool that writes out script commands to remove objects that are missing in the present case when saving out the auxiliary file to implement difference case changes.
    • Oneline Diagrams: Fixed bug parsing bus numbers. Extra whitespace created error converting the text to a number. This has been fixed.
    • PV and QV Curve (PVQV) Tool: When loading an auxiliary file using the Load Auxiliary button on the PV dialog, set the options in the PVCurve_Options object to match what is set on the dialog. If this is not done and the auxiliary file that is being loaded does not contain PVCurve_Options, options on the dialog will change if they are different from what is in the PVCurve_Options. This doesn't make any sense so make sure the options are set correctly.
    • Transient Stability: When using the script command TSGetResults() or the SimAuto command TSGetContingencyResults(), there was bug that could occur in some circumstances. This has been fixed.
    • Transient Stability: The new fields to specify that the field "ROCOF (Hz)" be stored in RAM for a bus in transient stability was added in Version 20. The characters ( and ) where messing up the AUX file format however as these showed up in the variable name in the AUX file. For the variable names these have been removed in the variable names to fix this.
    • Transient Stability: Fixed error with implementation of REPC_B that effected only Verison 20. It was not properly communicating the Vref signals to multiple electrical control models.

October 11, 2017

Features and Improvements

  • Difference Case Tool: In the Present Topological Differences from base case tool, the removed objects did not support the case information display filtering by owner, but only display filtering by Area/Zone. This has been modified to also support Owner filtering.
  • Security Constrained OPF (SCOPF) Tool: Added the contingency name to the 'Bus Marginal Controls' header to allow correlation between the controls and 'LP Basic Variables'
  • Security Constrained OPF (SCOPF) Tool: We have added a column on the LPVariables grid to show the contingency name that corresponds to the variable. Previously it was possible to have variables with the same ID, making it impossible to uniquely identify a variable.
  • Transient Stability: Made more descriptive validation error messages for REPC_A and REPC_B when the model does not have a measurement branch specified. Unless this model is only controlling voltage, then a branch must be specified at which the Qbranch, Pbranch, and/or Ibranch is measured. If the branch is not specified when it is needed an error message will appear indicating why the measurement is needed.
  • Bug Fixes

    • Contingency Analysis: Fixed reading of ViolationCTG objects from an AUX file when reading in custom monitor violations. These were not being read in when multiple of the same custom monitors violations for different violated elements under the same contingencies.
    • Difference Case Tool: In the Present Topological Differences from base case tool, there was an inconsistency when writing out the AUX file that changes one case into another if a device such as a branch, gen, shunt, or lineshunt was
      1. Assigned to the default bus owner in the base case
      2. Assigned to the same owner in the present case
      3. But the default bus's owner was changed
      The problem occurred because when reading an AUX file, Simulator's behavior when a bus owner changes is that any device connected to that bus (gen, load, shunt) that has the same owner as the bus will automatically follow that ownership change. Thus after reading the AUX file you would see the owner of the device (gen, load, shunt) change when you had not expected it to. The fix for this was to modify what is shown for a devices ownership in the Change mode so that if this occurs the device acts as though it's ownership has changed. Thus this would get included in the AUX file and the appropriate behavior would be seen.
    • Difference Case Tool: When saving out the auxiliary file of case changes when using the Difference Case tool, we now include a section that changes the owner of buses in the following situations:
      (1) The owner of the bus has changed between the Present and Base Case
      (2) A new device has been added that is attached to the bus and the owner of the new device is different than the owner of the bus in the Base Case
      (3) A new device has only one owner
      Writing out this additional section will prevent the situation in which a new device is added to a case and the owner matches the owner of the bus to which it is being added. This will mark the device as having the default owner. If the owner of the bus then changes the owner of the device will also change. We want to retain the owner of the device as it was assigned when the device was created. Changing the owner of the bus prior to adding the new device prevents this problem.
    • Oneline Diagrams: Fixed bug parsing bus numbers when read from a KML file. Any extra whitespace created error converting the text to a number. This has been fixed.
    • Transient Stability: Fixed a bug with writing REECB1 from a REEC_B model. It was casuing an access violation when saving a dyr file.
    • Transient Stability: Fixed an access violation that could occur when opening the load dialog for any load. An access violation could occur if a transient stability distribution equivalent had been assigned to the load.

October 6, 2017

Features and Improvements

  • Transient Stability: Modified new DER_A model to add parameter Trf and Vpr
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug in SendToExcel Script Command. The objectname was not being saved into Excel File in the first row.
    • Time Step Simulation: Fixed an access violation that could occur on the Time Step Simulation dialog. This was related to specifying the hour at which the time step simulation could occur which was recently added.
    • User Interface Dialogs: Bug fix in the object chooser -- due to an internal change between v19 and v20, the behavior of the search box changed from matching patterns at the beginning of the target string to matching patterns that occurred anywhere in the target string. The search box is now back to matching from the beginning of the target string (unless explicitly specified otherwise with an asterisk at the start of the search pattern)

October 5, 2017

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Made a commonly used feature much more memory efficient. The feature to Send To Excel by either right-clicking on the case informations display, or when using the related SCRIPT command, could cause Simulator to run out of memory when used on extremely large data sets.
  • Case Information Displays: Made a commonly used feature much more memory efficient. The feature to Send To Excel by either right-clicking on the case informations display, or when using the related SCRIPT command, could cause Simulator to run out of memory when used on extremely large data sets.
  • Scheduled Actions: Added another check when the Use Normal Status option is in use to return disconnects that are in series with the branch that is being returned to service. If a branch is an Open Breaker action, any disconnects that are in series with it and are normally closed will be closed.
  • Transient Stability: Added the requested ability to add the case name into the plot name when in auto save. If the option is checked then the name will have the following format: "ContingencyName_PlotName_CaseName.jpg" Otherwise it will be naming the plot as before.
  • Bug Fixes

    • Contingency Analysis: When doing a comparison of 2 contingency lists in the 64 bit version of Simulator, you coudl see a "stack overflow error". This has been fixed.
    • GIC: Fixed some issues associated with loading and saving *.gic format files.
    • Oneline Diagrams: Fixed a bug with PTDF pie chart displays, which were showing values off by a factor of 100.
    • Oneline Diagrams: Fixed error parsing ERCOT kml files caused by case sensitive text comparison. 'branch' was not matching 'Branch'.

September 28, 2017

Features and Improvements

  • Difference Case Tool: Added the GE Long ID field for loads to the Difference Case tool.
  • Scheduled Actions: When closing disconnects that are in series with breakers when using the Use Normal Status option, also close disconnects that are in series with Load Break Disconnects. This makes sense because we are treating breakers and load break disconnects the same when we are identifying breakers to open or close devices.
  • Bug Fixes

    • Time Step Simulation: When monitoring load results during the time step simulation, access violation could occur. This has been fixed.
    • Time Step Simulation: Added a new TSB version that will save load results. These were previously not being saved. Users will need to make sure that they have the latest version 20 patch or that they save the TSB in the correct version for the version of Simulator that they have.
    • Time Step Simulation: Fixed bug with reading loads for which custom results are monitored. The correct load ID was not being used so not all loads at a given bus were being marked as Time Selected = YES. Duplicate loads could also end up being added to the list of loads to monitor.
    • Time Step Simulation: When loading a TSB file that was saved in a later version than the current version of Simulator can handle, pop a message dialog indicating this.
    • Transient Stability: Fixed bug that would occur when running transient stability on a full-topology model.

September 26, 2017

Features and Improvements

  • Case Information Displays: Added new expression functions for converting floats representing a date time into strings and also converting strings formatted as date/times into floating point numbers. These function all follow similar syntax as used in Excel functions of the same name.
    (1) Text(floatvalue, "formatstring") --> returns a string with the floating point number converted to a data time string using the formatting specified in the format string.
    (2) DateValue("datetimestring") --> returns a floating point number representing only the integer part for the date/time floating point
    (3) TimeValue("datetimestring") --> returns a floating point number representing only the fractional part for the date/time floating point
    (4) DateTimeValue("datetimestring") --> returns a floating point number representing the date/time floating point
    See the PowerWorld help documentation for more information on the format string. Search "Formatting String" in the help.
  • PV and QV Curve (PVQV) Tool: Added a new field to a load for "ScaleMvar". This field defaults to YES. Set to NO to prevent changing the Mvar of this load when shifting power using an injection group (such as in ATC, PVQV, and System Scaling tools)
  • Transient Stability: added support to CHVDC2 to use the parameters which attempt to emulate commutation failure.
  • Bug Fixes

    • File Formats: When load an EPC file, the intermediate buses of multi-section lines have been modified to be assigned to the DataMaintainer of the branch section that connects to this intermediate bus. For example, a multi-section line has 2 sections and connects Bus A to Bus C, then after reading the EPC file Simulator will have branches from A - B and B - C. The intermediate bus B will be assigned the same DataMaintainer as the branch B - C.
    • General: Fixed random access violation that could occur when closing a case if it contains a VSCDCLine or trying to delete a VSCDCLine.
    • GIC: Fixed a bug the could occur when modeling geomagnetic induced currents inside the transient stability simulation. When doing this if a new islands was created during the simulation the simulation would fail. This has been fixed.
    • Oneline Diagrams: When saving a PWD file with many substation, area, or zone objects the saving could be very slow because of saving the swap list that is used when loading the oneline using name_kV linking. This has been fixed.
    • Oneline Diagrams: Renumbering the substations, areas, or zones in a case or oneline that contains many of these objects could be very slow. This has been fixed.
    • Oneline Diagrams: Loading a PWD file containing many substation, area, or zone objects could be very slow when using name_kV linking. This has been fixed.
    • Power Flow Solution: It is possible to end up with a case that has no viable islands. If this happens, the maximum mismatch values for the case are initialized but never set to anything real. An access violation could occur when reporting the maximum mismatch. This has been fixed and the maximum mismatch will be reported as 0 occurring at bus None in a case with no viable islands.
    • Simulator Automation Server (SimAuto): The fix to make Distributed Computation work from September 21, 2017 patch broke the function of SimAuto on a single machine. This fixes this bug.
    • Time Step Simulation: Removed the time step simulation option to enable area interchange. Now always use the Simulator option to enable area interchange. Having two different options was very confusing.
    • Transient Stability: Fixed a bug that was allowing the Auto Insert Transient contingency to enabled the modification of the event duration ONLY when a Gen was selected but only when a Gen was selected is when it should not be enabled.
    • Transient Stability: Fixed some parameter name inconsistencies on the REGC_A, REEC_A, REEC_B, REEC_C, and REPC_A models.
      * REGC_A: Parameter name changed to Tg (was Td); Parameter name changed to Tfltr (was T_LVPL)
      * REEC_A, REEC_B, REEC_C: Parameter name changed to Trv (was Tv)
      * REPC_A: Parameter names changed to fdbd1 and fdbd2 (was dbd1 and dbd2)
      These new parameter names match what the standard model was supposed to be so we have changed it to avoid ongoing confusion. Also, these new names match what was on the block diagrams in PowerWorld's help as well.
      In coordination with this, also modified so that when reading AUX files or copy/pasting from spreadsheet the old parameter names will still be recognized and read in appropriately so that old files can still be used.

September 21, 2017

Bug Fixes

  • Data View: When switching the Type of object on the Data View dialog an access violation would occur. This has been fixed.
  • Distributed Computation: Made distributed computation connections to remote machines more robust and reliable. This fix was required due to changes in remote connections made for Version 20.
  • File Formats: When loading the Areva contingency file include the name of the contingency in the message log when a message is written about not being able to find the object in the contingency elements.
  • File Formats: When loading the Areva contingency file and a contingency with the same name already exists prior to loading the file, clear out all elements in the contingency and only keep the ones that are included in the file currently being read.
  • File Formats: Fixed some bugs when loading the Areva contingency file when contingencies are already defined in the case. This fix will allow all existing contingencies to be kept and the file will simply append contingencies to the list.
  • Oneline Diagrams: When reading a PWD file saved prior to 6/2/2008 in the 64-bit version of PowerWorld Simulator 20, it was possible for the file to fail to load. This bug has been fixed so that the PWD file can be opened.
  • Scheduled Actions: Added a new feature to the Scheduled Actions dialog -- in the Options tab, users can now opt to disable automatic evaluation when changing the View Time, and instead manually evaluate the current time either by a button in the GUI, or with the SetScheduleView script command.
  • Transient Stability: Fixed a the issue that was causing the transient stability simulation to fail when an Island was created during the simulation due to branch status changes.
  • Transient Stability: Fixed some errors in the implementation of the CHVDC2 generic DC Transmission line dynamic model.

September 19, 2017

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed an intermittent bug that could occur when running the OpenOneline script command. The error would appear as an access violation.
  • Case Information Displays: When loading an advanced filter which were comparing Date/Time fields (such as in Scheduled Actions), it was possible for the Date/Time to be interpreted incorrectly. This has been fixed.
  • Difference Case Tool: In the Difference Case Mode of "Base", Modified the BranchDeviceType for three-winding transformer windings so that it returns "Transformer Winding" instead of the "Transformer". This change had already been made in Present Mode for Version 20 but was not done for Base Mode.
  • File Formats: Fixed error in writing out an EPC file. It was possible for the DC converter of a two-terminal DC line to write out a Psched = 0.0 improperly. When read back into Simulator, a 0.0 value for Psched was automatically replaced by the Pac value so this was not noticed in Simulator, but it should not be written as a 0.0
  • Scheduled Actions: Added checkbox to allow the user to clear any Added or Extra actions before re-running Identify Breakers
  • Scheduled Actions: Fixed a bug with the "Check Conflicts" tool which identifies schedules that perform conflicting actions on the same device at the same time. The bug was related to not properly handling scheduled actions that did not refer to a device (the device field is blank).
  • Transient Stability: Fixed an error in SVSMO1 related the timer which controls controllable fixed shunts. The timer was not properly resetting if the B of the shunt returned to acceptable limits.