Simulator 16 Patches

New Features

Bug Fixes

Date

January 2, 2014

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Fixed bug in ConditionVoltagePockets that would always indicate that the script failed.

December 19, 2013

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Replaced script command ConditionVoltagesOnRadialBuses added in the 12/9/13 patch with script command ConditionVoltagePockets(VoltageThreshold, AngleThreshold, Filter); This script command will cover the same situations as the previous script command in addition to other situations. It will identify pockets of buses bounded by branches that meet the condition that the absolute value of the voltage difference across the branch is greater than VoltageThreshold or the absolute value of the angle difference across the branch is greater than AngleThreshold and the branch meets the specified filter. The buses contained within these pockets will have their voltages estimated based on the assumption that the voltages at buses outside these pockets are good.
  • Auxiliary Files (SCRIPT and DATA Sections): Allow special keywords @DATETIME, @DATE, @TIME, @BUILDDATE, and @VERSION to be used as part of the filename for SaveDataUsingExportFormat, SaveData, SaveDataWithExtra, SaveObjectFields, and WriteToTextFile script commands. These special keywords will be replaced with their actual values when the file is saved.

December 9, 2013

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added script command ConditionVoltagesOnRadialBuses(VoltageThreshold, AngleThreshold, FilterName). The goal of this script command is to find groups of radial buses that may have bad initial voltage estimates and to get a better voltage estimate of these buses based on assuming that the voltages on buses outside of the radial group are good. These radial groups are determined by finding branches that would cause islands AND the voltage difference (absolute value) across the branch is greater than the VoltageThreshold in pu OR the angle difference (absolute value) across the branch is greater than the AngleThreshold in degrees, thus identifying parts of the system that have large voltage or angle differences. The FilterName is optional and determines which branches will be examined. If not specified all branches are considered.

December 3, 2013

Bug Fixes

  • Power Flow Solution: Improved Angle smoothing routines in some situations

November 12, 2013

Features and Improvements

  • General: When defining expressions for objects, a new option has been added to treat blank entries as zeros in the expression instead of treating the entire expression as invalid.

October 8, 2013

Bug Fixes

  • Case Information Displays: In some circumstances, calculated fields would not appear in the list of available fields for an object type. This has been fixed.

September 18, 2013

Bug Fixes

  • Power Flow Solution: In some situations power flow divergence could result if switched shunts were set to control the Mvar output of generators. This has been fixed.

September 17, 2013

Bug Fixes

  • General: When using the name of an expression or calculated field instead of the location number in a variablename that is part of an advanced filter condition, the variablename could not always be correctly determined resulting in the condition not being evaluated correctly. This has been fixed.
  • General: When identifying an expression variablename using the name of the expression instead of the location number, the correct variablename was not being identified. This has been fixed.

May 9, 2013

Bug Fixes

  • Available Transfer Capability (ATC) Tool: The linear ATC calculations were not always being correctly done when phase shifters are included. This has been fixed.

May 8, 2013

Bug Fixes

  • Power Flow Solution: When trying to energize a dead island, an access violation could occur during the power flow solution due to the calculation that assigns voltages to the previously dead buses.

May 2, 2013

Bug Fixes

  • Oneline Diagrams: There was a problem with Memo Text objects not showing all lines of text if a background fill was applied. This has been fixed.
  • User Interface Dialogs: Fixed error when showing the combo box list of string expressions at the top of the Expression dialog. It was showing the list of numeric expressions instead.

April 5, 2013

Features and Improvements

  • Power Flow Solution: Added error checking for parallel transformers so that if they do not regulate the same bus (actually ZBR Bus group), then the transformer will be turned off control automatically and an appropriate message written to the log
  • User Interface Dialogs: Modified the list of recently open files so it will dynamically increase the visual width when file names become extremely long so that the entire file name can still be viewed.
  • Bug Fixes

    • Contingency Analysis: When using the DC Approximation inside of contingency analysis, the monitoring of interface MW flows was not working properly. This has been fixed.
    • File Formats: When loading an EPC file, changed the default setting of "Sharing of generator vars across groups of buses during remote regulation" so it default so use the SUM OF user-specified remote regulation percentages.
    • File Formats: When reading a RAW file, modified to handle bus records which omit the voltage magnitude and angle. If these values are omitted, then we assume a magnitude of 1.0 and an angle of 0.0. Previously it would cause an error when reading the file.

March 29, 2013

Bug Fixes

  • File Formats: Fixed a bug that would not allow a RAW file to load. The message log would indicate that the file was loaded successfully, but no data at all was loaded.

March 28, 2013

Bug Fixes

  • Power Flow Solution: Fixed a power flow convergence problem that could be caused by generators being taken off AVR control due to them oscillating by repeatedly hitting and backing off Mvar limits. This problem could occur if using the option to check generator Mvar limits immediately and the option to prevent controller oscillation.

March 22, 2013

Bug Fixes

  • Contingency Analysis: Fixed an access violation that could occur when running contingency analysis. This would only occur if a case contained areas spanning multiple islands.
  • Power Flow Solution: A bug was introduced in the March 14, 2013 patch that affects the remote regulation of generators that are regulating buses within the same grouping of buses connected by very low impedance branches. This could lead to convergence problems with the power flow. This has been fixed.
  • Simulator Automation Server (SimAuto): Complex values were getting returned as integers when using any of the GetParameters functions. This has been fixed.

March 14, 2013

Features and Improvements

  • Oneline Diagrams: Flow arrows based on Custom Float 1 will now work with the Difference Flows options showing Difference Case and Base Case.
  • User Interface Dialogs: When using the Difference Flows options for showing Difference Case and Base Case, Custom Float values will now be shown correctly in user dialogs.
  • Bug Fixes

    • Contingency Analysis: When determining which buses are remotely regulated by generators, Simulator considers buses that are connected by very low impedance branches to be the same. This will allow coordination of generator regulation among buses that effectively control the same bus. In certain situations, contingencies that cause the groupings of the low impedance branches to change could result in a generator not regulating the correct bus. This could lead to an incorrect power flow solution. This has been fixed.

March 7, 2013

Bug Fixes

  • Bus View and Substation View Onelines: Make fonts on bus views scale in relation to the smaller screen dimension so scaling remains consistent in portrait mode.
  • Oneline Diagrams: Fixed a bug when copying and pasting oneline display objects along with their layers.
  • Oneline Diagrams: Fixed a bug caused when reading a PWD file that would not allow selecting the correct display object.
  • User Interface Dialogs: Added a Test button on the Expressions dialog to validate the expression and help with expression design. After specifying the expression function, clicking this button will either provide the value of the result or an error message if the expression is not valid.
  • User Interface Dialogs: Added better error checking and reporting of errors for Expressions.

February 21, 2013

Bug Fixes

  • Contingency Analysis: Cleaned up the reading/writing to/from an AUX file of the various Advanced Limit Monitoring options associated with violations based on a change relative to the reference state.
  • Contingency Analysis: Fixed a very large memory leak that occurred when using incremental topology processing in contingency analysis
  • File Formats: Fixed error when writing out negative values of series resistance for a branch to an EPC file.
  • File Formats: When reading in three-winding transformer records from a RAW file, we now allow a terminal bus to be specified which is NOT listed in the bus records if the STAT field indicates that the respective winding is OPEN. Thus the tertiary bus can be omitted from the bus table if the STAT=3, secondary if STAT=2, and primary if STAT=4. In these situations, Simulator will automatically create the bus number referenced as a terminal of the three-winding transformer and write an appropriate message to the log. Recent MISO cases were found to contain this structure for 145 transformers.

January 29, 2013

Features and Improvements

  • Case Information Displays: Added a field with generators, Mvar Capability Curve Is Defined, to indicate if the generator has a curve and not if the curve should be used. No longer create a default curve when setting the Use Mvar Capability Curve option to YES through the generator case information display and a curve does not already exist. A default curve will only be created if setting this option through the generator dialog and a curve does not already exist. A curve can only be used if one has been created and the option to use it is set.
  • Time Step Simulation: Added a button on the Results tab that will allow you to send all results to Excel. The format and data that gets sent will be the same as when sending each table to Excel one at a time. Only the results tables that actually have objects defined will be sent to Excel. All results will be sent to a new workbook in separate worksheets.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: Allow other dialogs to be accessed when opening the Limit Monitoring and Violations dialog from the ATC dialog.
    • File Formats: When appending switched shunt data from an EPC file and attempting to keep the IDs unique, instead of always modifying the Bus Shunt Fixed ID if there is a conflict, modify the ID of the shunt that is flagged for delete if there is one. The Bus Shunt Fixed will be modified if both shunts are flagged for delete. This is intended to set the ID of the shunt that shouldn't be deleted to the desired value if attempting to replace an SVD with a Bus Shunt Fixed or vice versa.

January 21, 2013

Bug Fixes

  • Power Flow Solution: Magnetizing conductance for transformers and conductance for lines were not properly being accounted for when solving the dc power flow using island based AGC with an injection group. This would cause the system slack to keep increasing by the amount of conductance. This was fixed by including conductance values as part of the shunt values reported for islands, areas, and the case when in dc power flow mode.

January 17, 2013

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added optional parameter FileType to DetermineBranchesThatCreateIslands(Filter,StoreBuses,"filename",SetSelectedOnLines,FileType) script command to specify the file format. CSV format is now available in addition to the existing AUX format. CSV format puts pairs of islanded buses and the branches that island them on the same line.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug in the Scale script command that would not scale properly if scaling based on MW, Mvar.
    • Available Transfer Capability (ATC) Tool: When using a power flow case with multiple islands, OTDF values for branches not contained in the "main" island were not properly calculated. The "main" island is defined to be the one with the most buses. This has been fixed.
    • Contingency Analysis: Fixed a bug that would not properly report interface violations when using one of the Advanced Limit Monitoring options that compares the violation results to base case conditions. This was only a problem when using one of the dc methods.
    • Sensitivity Calculations: Fixed a problem with TLR calculations when choosing the Slack as the transactor. Previously, the slack was determined from the island with the most buses. If the line or interface was not in the main island, no results were calculated. Now the slack is based on the island in which the line or interface is contained.
    • Transient Stability: Removed logging of initial limit violation for GGOV1 regarding fsrt. This represents one of three inputs into a low value select block and it is not uncommon for the limit to be exceed in the steady state solution, thus logging the violation is unnecessary.
    • User Interface Dialogs: When setting the dc loss multiplier for an area or zone, the dc loss multiplier for buses within those groupings will be set to the same value regardless of where you change the multiplier for the area or zone. Previously, you could only change the multiplier from the special DC Power Flow Loss Setup dialog that contains the loss multipliers.

January 4, 2013

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added ATCSetASReference script command that will allow setting the reference state used with the ATC tool.
  • Available Transfer Capability (ATC) Tool: Added ATCSetASReference script command that will allow setting the reference state used with the ATC tool.
  • Contingency Analysis Tool: The primary file format field, Actions - PW File Format, used with contingency elements (all contingency elements, contingency block elements, and global actions elements) will now be formatted by primary or secondary key field or label based on the Case Information Displays Key Fields setting.
  • General: Added fields for Branches showing the MW and Mvar losses on the series impedance only (I^2*x and I^2*R).
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): The SendToExcel script command has been modified to mimic more closely the functionality available when sending data to Excel from the GUI.
    • File Formats: When saving out switched shunts that are on either Generator Mvar or Wind Mvar control to an EPC file, the control will be set as fixed.
    • General: The star buses of three-winding transformers were not always in the correct substation. They should be assigned to the same substation as their primary bus. This has been fixed.
    • PV and QV Curve (PVQV) Tool: In some instances the number of critical scenarios could not be set greater than 1 because of a max limitation on the number of critical scenarios. This has been fixed by removing the max limit on the number of critical scenarios.
    • Transient Stability: The transient stability dialog will now refresh correctly after loading settings from an auxiliary file.
    • Transient Stability: Fixed an error in reading the DC4B model from a DYR file.

December 6, 2012

Features and Improvements

  • User Interface Dialogs: The Advanced Filter dialog now has a button that will allow you to save filters to an auxiliary file. There are three options: Save the current filter, save all filters of the current filter type, or save all filters.
  • Bug Fixes

    • Contingency Analysis: Fixed an access violation that could occur when saving a case after deleting a Custom Monitor. This would only occur if contingency analysis had been run and there were violations that contained the custom monitor that had been deleted.
    • Contingency Analysis: When reading a Shunt contingency element from an auxiliary file using labels for the shunt, the shunt could not be found resulting in an unlinked element. This has been fixed.
    • Transient Stability: Fixed bug that would not allow the Kis term for the GENTPJ machine model to be visible in the case information displays. This was only a problem with the term being visible in the table as it was being read and written correctly from file formats and could be edited on the generator dialog.

November 29, 2012

Features and Improvements

  • Contingency Analysis Tool: When converting contingencies defined by breakers to device contingencies, now have the option to keep the original contingency definition for any contingencies that end up with no elements after the conversion.
  • Transient Stability: Added showing the Status of dynamic models to the validation lists.
  • Bug Fixes

    • Contingency Analysis: When clicking the Abort button after clicking the Pause button on the contingency analysis dialog, the reference state was not being restored. The reference state is now restored any time that you click the Abort button.
    • Transient Stability: Modified the number of digits shown on the axis labels so that the formatting shows the appropriate number of decimal places.
    • Transient Stability: Fixed bug with Exciter model ESST3A caused by flipping the Tb and Tc parameters when the model was loded from a DYD file. This would cause an unstable response.
    • Transient Stability: On the Result Storage tab of the Transient Stability dialog under Store to RAM Options, that tables that allow selection of which fields to store could be filtered using the Area/Zone/Owner filters but it wasn't obvious that the tables were filtered. There is now an indication that the tables are being filtered and the Area/Zone/Owner filter option shows up in the Case Information Toolbar.
    • Transient Stability: The Results from RAM Time Values tables now have an indication in the table caption if they are being filtered by Area/Zone/Owner filters.

November 14, 2012

Features and Improvements

  • Transient Stability: Modified the feature which automatically inserts the Distribution Equivalent model into the network model of the power flow case. It will now copy the original load record's Memo and Custom Strings into newly created load records. Also modified the newly created load records IDs to now be "MA", "MB", "MC", "MD", "C1" for static load, and "PE" for the discharge lighting load.
  • Bug Fixes

    • Contingency Analysis: Fixed error with loading an auxiliary file which contained the CTG_OPTIONS object that contained the specification of the post-contingency auxiliary file (variable name = CtgFileName:1). The post-contingency auxiliary file was not being properly set and ended up begin set blank.
    • Oneline Diagrams: Modified how dragging of a bus with attached lines works if the line had exactly 3 vertices. Previously the middle vertex could be moved too much.
    • Transient Stability: Fixed error in display of TLVPL parameter for WT4G1 wind turbine model. This value could never changed from 0.02.

    • Transient Stability: Fixed error in initializing the WT4E model when the WT4T model was missing.
    • Transient Stability: Fixed error in auto-correction of the Vemax limit of a ESAC7B exciter.

November 1, 2012

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added option to control oneline linking when reading from script command OpenOneline. OpenOneline("myoneline.pwd","",NO,NO,LABEL); will link using labels, NAMENOMKV will link using nominal kV, and NUMBER will link using number.
  • Bug Fixes

    • General: Fixed an access violation that could occur after when opening a new case or closing Simulator after a case has been opened. This would only occur if the first case opened contained generators or branches with owners that had a zero percentage share.

October 31, 2012

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Modified the script command SendToExcel() to speed it up.
  • File Formats: Modified the export of EPC files to ensure the order in which multi-terminal DC converters are written conforms to a hard-coded ordering required by users in WECC when running transient stability user-written models.
  • General: Added option for economic merit order scaling for injection groups on the Scale dialog.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug trying to use the name of custom fields when defining filter conditions and the columns in Case Info Customizations. We were just looking for a generic variablename instead of looking for the variable name for the specific object class that is being used.
    • General: Update the owners lists when buses, gens, loads, or lines get deleted to prevent an access violation that would occur when the owner case information table was open or if there was an owner text field on a oneline.

October 23, 2012

Features and Improvements

  • Case Information Displays: Added a new Branch field to show the difference in bus angle at each end of the branch (From Angle - To Angle).
  • Contingency Analysis Tool: When showing Custom Monitors as Violations, show the name of the Custom Monitor as the Category instead of just showing "Custom."
  • User Interface Dialogs: Added the ability to save the Jacobian Matlab M file in scientific notation.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Sped up the SendToExcel script command. A workbook will now be saved in the current directory with the specified name.
    • General: Fixed circular reference errors that could occur as a result of renaming a model condition, model filter, or model expression.
    • Oneline Diagrams: Fixed a bug with copying and pasting screen layers from one oneline to another. Previously, an object would not be placed in the correct layer once pasted unless the screen layers in the new oneline were in the exact same order as the old oneline.
    • Time Step Simulation: Increased the number of time points that may be inserted at one time to 100,000.
    • Transient Stability: When converting the CMPLDW model to component parts in the power flow, fixed some problems with initializing the component parts.
    • Transient Stability: Added error checking on the GAST_GE and URGS3T governor models to automatically increase Lmax if it is initially too small.
    • Transient Stability: Fixed a bug that would not implement injection group gen drop correctly.

October 10, 2012

Bug Fixes

  • Contingency Analysis: Fixed a potential problem when loading contingency options from an auxiliary file and specifying the Post-Contingency Auxiliary File if not specifying the directory path explicitly.
  • Contingency Analysis: An access violation could result if deleting contingencies with the Contingency Analysis dialog open. This has been fixed. This bug was caused as a result of the addition of the What Actually Occurred tab for a single contingency in the October 8, 2012 patch.

October 9, 2012

Features and Improvements

  • Oneline Diagrams: Can now include multi-section lines with the KML file export and import options.
  • Bug Fixes

    • General: The October 5, 2012 fix that improved speed of loading a large number of Model Expressions or Custom Expressions from an auxiliary file caused a potential bug where Model Filters stored in a PWB file would not be loaded correctly. This could result in an access violation. This has been fixed.

October 8, 2012

Features and Improvements

  • Contingency Analysis Tool: Added What Actually Occurred tab next to the Violations tab on the Contingency Analysis dialog to show what occurred for the selected contingency.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When using the CloseWithBreakers script command, devices will now have their status set to closed if they are open in addition to closing breakers to close the device. Previously if the status of the device was open, the device couldn't be closed by closing breakers.
    • File Formats: Fixed reading in an Areva HDB Export CSV file to handle reading information from the last TAB record properly.

October 5, 2012

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Can now refer to custom expression by name rather than number location of the field. Instead of using "CustomExpression:location" can now use "CustomExpresion:name". Using this option for custom expressions requires that a name be specified for the custom expression
  • Auxiliary Files (SCRIPT and DATA Sections): When saving out an entire case as an auxiliary file, the field "AllLabels" is included for each object type that allows labels and has some labels defined.
  • Auxiliary Files (SCRIPT and DATA Sections): Improved speed of loading a large number of Model Expressions or Custom Expressions from an auxiliary file.
  • Auxiliary Files (SCRIPT and DATA Sections): Allow the SaveCase script command to take special keywords as part of the filename. Simulator will replace these special strings as desired when creating the filename to save. @DATETIME will replace the keyword with the actual date an time in the format yyyymmdd_hhnnss-hhmm with the UTC offset included on the end of the time. The other special keywords @DATE, @TIME, @BUILDDATE,and @VERSION can also be used but are not as useful as the @DATETIME.
  • Case Information Displays: Show the "Disable If True in CTG Ref" and "Evaluate in CTG Ref" fields by default with the Model Condition case info.
  • Transient Stability: Add ability to right-click on a plot series trace in a transient stability plot and choose "Bus View". This will automatically open the bus view related to the object associated with the plot series.
  • User Interface Dialogs: Add an option the bottom of any dialogs System Menu for "Print" which will send an image of the dialog to the printer.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): Using the script command "Scale" with injection groups, the scaling was not functioning properly since the patch release on August 24, 2012. This has been fixed.
    • Power Flow Solution: Fixed error in how area interchange was handled when solving a DC power flow solution in a case which had transformers with non-zero magnetizing conductances.
    • Transient Stability: Fixed error in the transient stability contingency command requesting that loads within an Injection Group be opened. Previously this wasn't working properly.

September 27, 2012

Bug Fixes

  • Integrated Topology Processing (ITP): If using a full-topology case with the Use Consolidation option set to true in Simulator without the Integrated Topology Processing add-on, the power flow might fail to converge. This has been fixed.
  • Power Flow Solution: When a switched shunt is on Wind Mvar Control Regulation and the generator that it is controlling is opened, the shunt Mvar injection will be set to zero.

September 20, 2012

Bug Fixes

  • Power Flow Solution: Fixed an access violation that could occur in the angle smoothing process if closing in a series of zero impedance branches.

September 17, 2012

Bug Fixes

  • Contingency Analysis: If you had contingency records defined with contingency specific solution options and saved the contingency definitions to a PWB file, this could cause the case size to increase each time that you saved the case. This has been fixed. This fix will also reduce the case size of any case saved with this problem.

September 12, 2012

Features and Improvements

  • Integrated Topology Processing (ITP): When determining the Derived Status of a device and a closed breaker is found, we now look for a connected generator, load, or closed branch on the other side of the breaker to fully determine that the device is closed.
  • Bug Fixes

    • Contingency Analysis: Using secondary key fields to identify DC line contingencies in an auxiliary file was not working when loading the file. This has been fixed.
    • Oneline Diagrams: When exporting a oneline as a GIF, the background was not being set correctly. This has been fixed.

August 30, 2012

Features and Improvements

  • Case Information Displays: Added the ability to specify the Key Fields type from the Case Information Toolbar.

August 24, 2012

Features and Improvements

  • General: Supplemental Data can now be used with Custom Model Expressions.
  • Transient Stability: Added CSV file format for Play In structure so that data can be read and written to facilitate quickly getting data into Simulator for plotting comparison purposes.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When writing out center x and y locations for display objects and then reading them back in through an AXD the objects would not show up in the correct location. This has been fixed.
    • Available Transfer Capability (ATC) Tool: Before calculating the linear step after solving the contingency when using the full contingency iterated method, restore the max and min gen limits and participation factor. These could get changed during the contingency solution and only the original values are applicable for calculating the linear step.
    • General: When using the MAX GEN INC and MAX GEN DEC options for determining injection group participation factors, units will now abide by their limits. Previously, the limits were being ignored which could result in negative participation factors.
    • General: Fixed scaling loads from the Scale dialog when using the Scale Only AGCAble Generation and Load option. Now only the AGCable loads will scale, but the non-agcable loads will figure into the total. The user sets the scaling factor/total load that is desired and internally Simulator determines the new scaling factor for the AGCAble load only so that the AGCAble load is adjusted. When the AGCable load is then added to the non-agcable load, the result will be the desired scaling factor/total load.
    • PV and QV Curve (PVQV) Tool: Modified the "New Plots" to force enough digits on the axis so that variation can be seen.
    • Transient Stability: Modified the plotting to force enough digits on the axis so that variation can be seen.
    • Transient Stability: For the REMCMP model, set the remote bus to the terminal bus if the remote bus cannot be found. This could result when making two-bus equivalent cases.
    • Transient Stability: Fixed memory leaks associated with TSGetResults script command.
    • Transient Stability: Added ability to delete Transient Limit Monitors.
    • QV Curve Tool: If the base case power flow solution fails to solve at the beginning of a QV run and we are not making the base case solvable, the tool should now fail gracefully and produce an appropriate error message. Previously, the run could freeze and could leave the case in an unknown state.

August 7, 2012

Features and Improvements

  • Integrated Topology Processing (ITP): When determining the Derived Status of a device (branch, gen, load, shunt, etc.) by interrogating the system topology, we will no longer consider a Load Break Disconnect as something which will signify that a device is CLOSED.
  • Integrated Topology Processing (ITP): When determining the Derived Status of a device by interrogating the system topology, we will no longer consider a breaker that is directly in series with a switched shunt as something which will signify that a device is CLOSED (except for that particular switched shunt of course).
  • Integrated Topology Processing (ITP): When determining the Derived Status of a device by interrogating the system topology, we will no longer consider a breaker that is in parallel with another type of branch as something which signifies that a device is CLOSED. This is meant to eliminate the consideration of breakers which represent bypass breakers such as for a series capacitor.
  • Transient Stability: Added ability to store the Transmission Line Relay Model states to hard-drive. Previously these could only be stored to RAM.
  • Bug Fixes

    • File Formats: Fixed a problem when reading back in a PWB file which contained Model Expressions which referenced a Model Filter or Model Condition. This reference would be lost after loading back in the PWB file.

July 30, 2012

Features and Improvements

  • Transient Stability: Modified transient initialization so that MTDC converter voltage setpoints are initialized the initial DC voltage of the MTDC bus. This was done so that the converter always initializes to a flat start even when no dynamic model is given.
  • Transient Stability: Added parameter checks on the Tdr time constant for Ac7B and AC8B so that if it is zero it treats Kdr as zero as well.
  • Transient Stability: When using a LDFR model, we now apply the frequency dependence to the transient stability default load model instead of the underlying power flow ZIP model. Using the underlying model commonly results in a constant power flow load model which is a problem.
  • Transient Stability: Modified validation of T1 for the URST5T and ST5B exciter.
  • Transient Stability: Added more error checking on Xdpp and Xqpp to enforce values that values must be greater than 0.05.
  • Transient Stability: Limited how much bigger Xqpp can be than Xdpp in GENTPF and GENTPJ. If Xqpp > 1.1*Xdpp then Xqpp := 1.1*Xdpp
  • Transient Stability: Modified ESAC8B_GE exciter validation so that Vfemax must be greater than 3.0
  • Transient Stability: Modified GGOV1 validation so that Kturb must be greater than 0.1
  • Transient Stability: Modified GGOV1 validation so that Vmax <= 1.0 and Vmin >= 0.0
  • Transient Stability: Modified GPWSCC validation so that R >= 0.1
  • Transient Stability: Modified G2WSCC validation so that Velopen and Velclose must surround zero.
  • Transient Stability: Modified URGS3T and GAST_GE validation so that B >= 0.1
  • Transient Stability: Modified validation of WT1G and WT2G to ensure proper relationship between Ls > Lp >= Lpp > Ll
  • Transient Stability: Modified validation of WT1G and WT2G to ensure Tpo > 0 and Tpoo >= 0 and also multiple of the time step
  • Transient Stability: Added validation check for GGOV1 on Kpgov/Kigov to prevent numerical instability. If it results in too small a time constant, then Kpgov is set to zero.
  • Transient Stability: Modified use of subinterval integration with induction machine based models (WT1G, WT2G, WT1G1, WTG2, GENWRI, CIMTR?, etc...) to use it more liberally if Tpo or Xp are too small.
  • Transient Stability: Modified ST5B, ESST5B, and URST5T validation of the T1 time constants
  • Bug Fixes

    • Contingency Analysis: When clicking on one of the fixed columns in the contingency analysis list, the violation list and contingency definition list was not updated immediately. This has been fixed.
    • Oneline Diagrams: Right-clicking on a background line and choosing to convert the background line to a multi-section line would not function if the oneline presently had no buses on it. This has been fixed.
    • Transient Stability: Fixed access violation that could occur when looking at the transient limit violation table while the simulation was running.
    • Transient Stability: The options to specify when to start transient limit monitoring was not be automatically saved to the AUX when storing the transient options. This has been fixed.
    • Transient Stability: Removed error check on enforcing that T10 > 0 from PSS2B. This is not necessary.
    • Transient Stability: Fixed error in limit enforcement of VfeMax for ESAC3A

July 13, 2012

Features and Improvements

  • File Formats: Added reading of UCTE (European) file format.
  • Bug Fixes

    • Transient Stability: Fixed errors when opening one end of a transmission line if it had no shunt charging.

July 10, 2012

Features and Improvements

  • PV and QV Curve (PVQV) Tool: Added the option to plot pre-contingency values on the horizontal axis with the "New Plots" used with the PV tool.
  • PV and QV Curve (PVQV) Tool: Import and Export can now be plotted on the horizontal axis with the "New Plots" used with the PV tool.
  • Transient Stability: Optimized MOTORW model to increase simulation speed slightly.
  • Bug Fixes

    • General: Deleting MW Transactions while in Run Mode could cause access violations. This has been fixed.
    • PV and QV Curve (PVQV) Tool: Added PV messages to indicate that a source or sink injection group has no participation points when it is empty rather than indicating that the points in the group are not in the same island.
    • Transient Stability: The fix in the 6/26/12 patch to fix access violations caused by showing a Results grid with open generators caused a problem that would end up showing blank entries for the state variables in the Results grid. This has been fixed.
    • Transient Stability: Fixed problem with extra blank lines being written to the message log during validation.
    • Transient Stability: Fixed a problem with the PDCI model which could cause the simulation to crash in some situations.
    • Transient Stability: Set the high end of the valid voltage range correctly when determining if a switched shunt is within range or if it might need to switch.
    • Transient Stability: Report zero for a switched shunt's nominal Mvar if the shunt is not inservice.

June 26, 2012

Features and Improvements

  • File Formats: When writing out an EPC file, the generator baseload flag is now written as a 2 if also using the option that the baseload flag means to prevent post contingency AGC response and post contingency AGC response is being prevented.
  • General: Testing
  • Oneline Diagrams: Added option to convert a background line to a multi-section line.
  • Oneline Diagrams: New multi-section lines can now be created by adding a new multi-section line object to a oneline diagram.
  • Oneline Diagrams: Model Conditions and Model Filters can now be selected for Generic Model Fields on a oneline diagram.
  • Transient Stability: Added two new fields with the transient contingency results to report the total load and total gen tripped during simulation of that contingency.
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When using the SaveData script with CSVColHeader file type and saving multiple TLR results, the column headers are now properly displayed for the multiple TLR elements instead of displaying a generic header.
    • Case Information Displays: When viewing the Bus case information display, switched shunt MW information was not being displayed. This has been fixed.
    • File Formats: When loading in an EPC file, the IDs of bus shunts (Bus Shunt Fixed Control Mode in Simulator) will be changed to new unique IDs if SVDs (non-Bus Shunt Fixed Control Mode in Simulator) are read in with the same ID at the same bus. Previously, switched shunts with the same ID at the same bus would just be overwritten. SVDs with the same ID can still overwrite each other and Bus Shunt Fixed with the same ID can still overwrite each other.
    • General: When using Difference Flows and viewing the Difference Case, the MW generation for a bus was showing the sum of the generation for the two cases instead of the difference. This has been fixed.
    • General: When creating an equivalent, owners were not getting updated. This has been fixed.
    • Sensitivity Calculations: When using the SaveData script with CSVColHeader file type and saving multiple TLR results, the column headers are now properly displayed for the multiple TLR elements instead of displaying a generic header.
    • Time Step Simulation: When saving results to a CSV file, the results were all being saved to a single line in the file. This has been fixed.
    • Transient Stability: Fixed a bug on the Transient Stability dialog if you were on the Simulation page. If you selected the Definitions or Violations tab, the Control tab was shown without being refreshed correctly.
    • Transient Stability: Fixed some bugs with creating dynamic equivalents in cases with phase shifters.
    • Transient Stability: When creating dynamic equivalents, set the voltage setpoint for dynamic equivalent generators.
    • Transient Stability: When loading in contingency line elements from an auxiliary file and you had an event that opened or closed a line at the near end and the far end, the second event was not loading. This has been fixed.
    • Transient Stability: When a single relay sends multiple tripping amounts at the same time at the same time delay, the total amount that is tripped is now reported as a transient event.
    • Transient Stability: Fixed an access violation that could occur when showing the Results table that included generators that are open.

June 15, 2012

Features and Improvements

  • Case Information Displays: When choosing to "Send to Excel" from a case information display, previously Simulator would always split exports of more than 256 columns into separate sheets in an Excel Workbook. For Excel versions 2007 and later, it will now only do this for more than 16,384 columns instead.
  • Contingency Analysis Tool: Added new option with Model Conditions to "Evaluate in Contingency Reference State". This option will only be used when implementing a contingency and will return the result of the model condition as it was in the reference state rather than evaluating at the present state.
  • Transient Stability: Added ability to right-click on a plot in the plot designed and choose Generate Plot.
  • Transient Stability: During initialization, added additional limit violation checks for the WT4E wind turbine electrical model.
  • Transient Stability: When loading in a DYD file, Simulator will no longer prompt the user asking about whether to split generators as prescribed by a GENCC model. This will now always be done with appropriate info messages written to the log.
  • Transient Stability: Modified the layout of the transient stability dialog to give more direct access to the Transient Limit Monitor violations and also to combined lists all transient contingency elements and violations
  • Bug Fixes

    • Case Information Displays: Added ability to save the case information customizations for the OPFZones table.
    • File Formats: When reading an EPC file, if an Area's slack bus is specified to be a bus that is not inside the area, then the area will be set off of AGC and the area slack designation ignored.
    • File Formats: When reading an EPC file, if the generators at an Area Slack Bus are not assigned the same area as their terminal bus, then the generator area designations are changed to be the terminal bus area.
    • Power Flow Solution: When a transformer or switched shunt is turned off control because it is regulating a bus that is already regulated by a generator or switched shunt, the messages give an indication of whether it is a generator or switched shunt that causes something to be turned off control instead of just always saying generator. Also, now only online transformers and switched shunts will be turned off control.
    • Transient Stability: Fixed reading of the BBSEX1 exciter. The min/max values were being read in backwards for Vrmax/Vrmin and Efdmax/Efdmin Transient Stability: Modified HYGOV, HYGOV4, HYPID, WEHGOV and HYGOVR hydro governors so that after the Pgv value drops below 0.005 per unit (0.5% of potential gate position typically), then we model the water column dynamics as algebraic. This avoids a potential divide by zero problem, and extremely fast dynamics at very low power outputs which cause numerical stability problems.
    • Transient Stability: When loading in a TSLimitMonitor from an AUX file, the designated filter was not being properly read. This has been fixed.
    • Transient Stability: Modified so that the last two parameters of a WT4E model are optional and assumed as default if omitted.
    • Transient Stability: Improved wind turbine modeling for Type 3 and Type 4 wind turbines when operating at low voltage. If the low voltage, active current management is active then the network boundary equations will solve more quickly that previously.
    • Transient Stability: Fixed to include the proper numerical validation for the ESST5B, ST5B, ESST6B, and ST6B exciters is performed.
    • Transient Stability: Further improvements to the GENTRA model

June 8, 2012

Features and Improvements

  • Contingency Analysis Tool: Added an Area contingency action which can change the AGC method and any area slack designation (Bus or Injection Group).
  • Transient Stability: Modified the Insert Apply and Clear Fault button the Transient Stability dialog so that when performing this for a transmission branch it automatically added THREE actions: Apply Fault, BRANCH Open Near, and BRANCH Open Far.
  • Transient Stability: Modified the default Kis value for a GENTPJ model to zero (0.0)
  • Transient Stability: Reordered the list of Object Types on the Transient Stability Contingency Element Dialog so that those most frequently used are listed first and "Branch" is selected when the dialog first opened.
  • Transient Stability: Modified the Transient Stability Contingency Element Dialog to move the Save button to the top of the dialog to reduce confusion
  • Transient Stability: On the Results from RAMMinimum/Maximum Values tab, enabled the ability to Contour Columns on the case information displays
  • Transient Stability: Added a new column on the PlayIn Case Information display in the model explorer to show the Number of Signals and a list of the respective Signal Names
  • Transient Stability: Previously when opening both ends of a transmission line, Simulator would automatically clear any fault that was there, so that if in a subsequent event the line was closed back in the fault was no longer present. This has been modified so that the fault will remain until the user explicitly includes an event to clear the fault.
  • Transient Stability: When running a transient stability simulation, if the Multi-Terminal DC Converters is above its maximum current rating in the base case then in the stability simulation we assume the maximum current is equal to the base case current.
  • Transient Stability: Added Ownership columns to the validation objects
  • Transient Stability: Added additional validation checks to GENTPF to enforce that Tdopp>Delt*TimeStep and Tqopp>Delt*TimeStep
  • Transient Stability: Modified the initialization of the WT3E wind turbine electric model to ensure it initializes to exactly a zero derivative.
  • Transient Stability: Modified how Type 3 and Type 4 wind turbines are handled in the network boundary equations to improve solution convergence. (They are now modeled as a constant current explicitly.)
  • Transient Stability: Added additional validation checking so that for the GENTPF and GENTPJ models (Xdp=Xdpp) and (Xqp=Xqpp) are NOT allowed as the results in an invalid model.
  • Transient Stability: Added validation checking on the various time constants for wind turbine models to prevent numerical instability
  • Transient Stability: When loading an DYD file, warning messages are written to Simulator's log if an MVABase is specified different than the MVA base in the power flow case (presumably read from an EPC file). We now limit the number of warning messages to 30 so that the log is not overwhelmed if the case has a large number of these changes.
  • Transient Stability: When reading and writing a DYD, added an extra voltage measurement delay parameter for the WT3G and WT4G models
  • Transient Stability: For a REXS model with extremely high gain value (> 10,000) modified to use a larger subinterval integration (64 subinterval steps)
  • Bug Fixes

    • Auxiliary Files (SCRIPT and DATA Sections): When entering data in the transformer XF Auto field by pasting or from an aux file, an access violation could occur if the field is blank. Now a blank is just ignored and the field is not changed.
    • Available Transfer Capability (ATC) Tool: For ATC calculations, changed the internal threshold for excluding monitored lines if their PTDFs are too small from 0.001 to 0.00001. With this number too large, limiters could be excluded even if their OTDFs are significant.
    • Contingency Analysis: Fixed error with loading in Contingency Globals actions which contained comments when reading them from a SUBDATA section
    • File Formats: When reading and writing an EPC file we now properly interpret a three-winding transformer with status signifying that a single winding is open. We now interpret a value of 2, 3, or 4 to signify that the secondary, tertiary, or primary winding are open.
    • File Formats: When writing to an EPC version 18, Simulator was truncated bus names to 8 characters. This has been modified to truncate to 12 characters intead.
    • Integrated Topology Processing (ITP): Fixed an access violation that could occur when using the Close Breakers to Energize Switched Shunts.
    • Transient Stability: Fixed error with loading from an AUX file data related CMPLDW fields
    • Transient Stability: Fixed a problem with GenPlayIn not producing real and reactive power and now is reporting the results of MW and MVAR to the TS case info for Buses and Gen
    • Transient Stability: Previously a GENTPF or GENTPJ model with Tdopp = 0 or Tqopp = 0 resulted in a divide by zero error and NAN values in the solution resulting in solution failure.
    • Transient Stability: Simulator will now automatically detect if (Tdopp = 0) or (Tqopp = 0) and model the generator using a reduced order transient generator model of a salient pole machine with no amortisseur winding
    • Transient Stability: Modified the GENSAL and GENROU case information display lists so that they properly show non-default parameter values in a bold font
    • Transient Stability: Fixed a caption for Total Newton Iterations on the Transient Stability dialog's Results from RAMSummary tab
    • Transient Stability: Removed the Show Dialog button on the list of Transient Contingencies. There is no dialog to show so this didn't do anything before and caused confusion.
    • Transient Stability: Fixed an initialization error with the MTDC_PDCI model that could cause a no disturbance simulation to not run completely flat.
    • Transient Stability: When reading a DYD file, any MVABase specified with a WT1G, MOTOR1, GENIND, GENWRI, or WT2G was not being properly read. This has been fixed
    • Transient Stability: Modified stability to no change the minimum firing angle of DC line or converters in the stability simulation. Previously we changed these to 5 for rectifiers and 15 for inverters. We now just leave them alone.
    • Transient Stability: Corrected automatic Limit Correction of the WT3E wind turbine model when Xiqmin or Xiqmax were violated in the initial state.
    • User Interface Dialogs: Modified the Generator Dialogs to show the Zone and Area number for the generator object itself instead of for the bus. Normally these are the same anyway, but they are not always the same.

May 25, 2012

Features and Improvements

  • Fault Analysis: Added fields for displaying subtransient fault currents.
  • Power Flow Solution: When Simulator automatically picks a slack bus for an island, a generator that is regulating a bus outside the island will be picked as a last resort and set to regulate its own terminal. Previously, any generator not regulating a bus inside the island would be ignored which could result in an island not being viable even if it has generation.
  • Transient Stability: Added the MTDC_PDCI, CONV_CELILO, CONV_CELILO_N, and CONV_SYLMAR dynamic models. There is an option for these models to be automatically added if the PDCI model exists in the base case.
  • Bug Fixes

    • Contingency Analysis: Modified the accounting of gen drop overlap so that the total amount of overlap does not include multiple counting of overlap that applies to multiple injection groups. Overlap is only counted as generators are processed in merit order.
    • General: Fixed a bug that would not apply the NOT condition correctly for Model Conditions or Model Filters that are part of a Model Filter. This could occur if the Model Filters were loaded more than once from either a PWB or an auxiliary file.
    • Integrated Topology Processing (ITP): When using Integrated Topology Processing and solving a consolidated case, skip using the optimal multiplier for the first inner loop iteration after generator adjustments have been made. This should help convergence in situations in which the optimal multiplier is very small and the power flow is very slow to converge.
    • Oneline Diagrams: Fixed text fields with spinners so that they draw properly when background fill is also used.
    • Oneline Diagrams: Fixed an access violation that could occur when opening the Save View dialog.
    • Oneline Diagrams: Fixed GPU contouring bug to support older video cards.
    • Power Flow Solution: Fixed an access violation that could occur in the angle smoothing process when closing in a series of branches.
    • Power Flow Solution: When using Integrated Topology Processing and solving a consolidated case, skip using the optimal multiplier for the first inner loop iteration after generator adjustments have been made. This should help convergence in situations in which the optimal multiplier is very small and the power flow is very slow to converge.
    • Power Flow Solution: Fixed an error with generator AVR control when there are multiple generators at the same bus on AVR control and at least one of the generators does not have a viable path to the bus it is regulating. In certain situations, the regulated bus would be selected as the bus that does not have a viable path resulting in a failed power flow solution. This has been fixed so that the regulated bus is selected as a bus that has a viable path from the generator to the regulated bus.
    • Time Step Simulation: Custom Input field values can now be pasted from Excel into the appropriate tables.
    • Time Step Simulation: Fixed bug in handling of LL limits for ESAC6A, EXAC6A, and EXIVO exciters.
    • Transient Stability: Fixed error with reading the MVA base for wind turbines from GE DYD file. Previously for WT4G, WT3G, GENWRI, GENWTG, etc. the MVA base in the DYD file was being ignored.

May 9, 2012

Bug Fixes

  • Bus View and Substation View Onelines: If a oneline field contained an ampersand, text beyond the ampersand could be truncated. This has been fixed.
  • File Formats: Fixed a bug created by the May 7, 2012 patch when setting the voltages of radial buses when loading in RAW, EPC, or AUX files. Voltages could be incorrectly set if the radial branch had a tap ratio <> 1, a phase shift <> 0, or magnetizing conductance or susceptance. Voltages could also be incorrectly set of the radial bus contained bus shunts. Incorrect voltages could cause the power flow not to converge. All of this has been fixed.
  • Oneline Diagrams: If a oneline field contained an ampersand, text beyond the ampersand could be truncated. This has been fixed.

May 7, 2012

Features and Improvements

  • Oneline Diagrams: Now have options with Screen Layers to Show All Layers or Hide All Layers.
  • Oneline Diagrams: Modified how the list of Save View dropdown works. If a view is named using a back-slash, , a subfolder will be created in the list of views. As an example, New FolderView Name, will create a subfolder with the name New Folder and this folder will contain the view with the name View Name.
  • Bug Fixes

    • File Formats: When reading a PTI DYR file, do not write a message in the message log that the file reading has aborted because the file contains extra blank lines at the end.
    • File Formats: Various issues have been encountered with EPC and RAW files due to non-Unicode files and system encoding. Previous patches have attempted to fix this but have ended up creating problems with different system encodings. Default system encoding will now always be used.
    • File Formats: When loading in RAW, EPC, or AUX files, set the voltages at any radial buses to be the voltage of the bus at the other end of the radial branch as long as there is no shunt charging or conductance on the branch and there are no generators, loads, or shunts online at the radial bus. This is needed to prevent power flow convergence issues caused by bad voltages at these radial buses that are sometimes encountered when reading these text files.
    • Transient Stability: When reading a PTI DYR file, do not write a message in the message log that the file reading has aborted because the file contains extra blank lines at the end.
    • Transient Stability: For TLIN1 relay model, correctly trip only the first line segment between from bus and to bus when flag = 0 and nfar has been specified.
    • Transient Stability: CIM5 and CIM6 models assigned to open loads could not be started once the loads were closed. This has been fixed.

April 27, 2012

Bug Fixes

  • Auxiliary Files (SCRIPT and DATA Sections): Objecttype POWERWORLDSESSION provides access to a string containing the system slack buses. Variables for this object have been slightly modified since the April 26, 2012 patch. Now use variablename BUSSLACK:1 to return a string containing bus numbers and names of all system slack buses. Use variablename BUSSLACK to return a string containing the system slack buses along with MW and Mvar ouptut values and minimum and maximum limits.

April 26, 2012

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): The text field for script command WriteTextToFile and the Header_Value_List for script command SaveDataWithExtra will now allow special keywords to specify date, time, and version. @BUILDDATE, @DATETIME, @DATE, @TIME, and @VERSION will be replaced with the appropriate values.
  • Auxiliary Files (SCRIPT and DATA Sections): New objecttype POWERWORLDSESSION is now available that will provide access to the Simulator executable currently being used. Use variablename VERSION to return just the executable version and VERSION:1 to return a string listing the add ons.
  • Auxiliary Files (SCRIPT and DATA Sections): New objecttype POWERWORLDSESSION provides access to a string containing the system slack buses. Use variablename BUSSLACK to return a string containing bus numbers and names of all system slack buses. Use variablename BUSSLACK:1 to return a string containing the system slack buses along with MW and Mvar ouptut values and minimum and maximum limits.
  • Contingency Analysis Tool: Overlap Gen MW field is now available with contingency records to list the total amount of overlapped gen when accounting for overlaps in injection group actions involving Set To and Change By actions of opening generators in merit order.
  • Oneline Diagrams: Case Information Memo Text object now allows you to display system slack buses on a oneline diagram. The executable version information can be displayed as well. Currently, only the list of system slack buses without MW and Mvar information can be saved to the PWD, and only version information without the add ons can be saved.
  • Bug Fixes

    • Contingency Analysis: When calculating OTDF values for contingency violations, report the PTDF value even if the OTDF ends up being zero. Previously, we were also reporting zero for the PTDF. The Contingency Violation List table will now automatically be refreshed when calculating OTDFs.
    • Contingency Analysis: When using contingency analysis with topology processing it was possible for a non-primary bus to be reported as a low limit voltage violation if its superbus became disconnected during a contingency. This is no longer considered a violation and the bus will not be reported.
    • Contingency Analysis: When using contingency analysis with topology processing, the option to only monitor the primary bus for each superbus was working in the opposite manner. If the option was NOT selected, only the primary bus for a superbus would be monitored. This has been fixed.
    • File Formats: Problems could be encountered when loading text files with non-US English characters. This has been fixed.
    • File Formats: When reading Areva CSV file, LN records that do not specify one end are ignored.
    • General: Fixed a minor issue with switching away from and back to a dialog once it has been maximized. When you came back to the dialog it would no longer appear as if it was maximized.
    • Integrated Topology Processing (ITP): When using contingency analysis with topology processing it was possible for a non-primary bus to be reported as a low limit voltage violation if its superbus became disconnected during a contingency. This is no longer considered a violation and the bus will not be reported.
    • Integrated Topology Processing (ITP): When using contingency analysis with topology processing, the option to only monitor the primary bus for each superbus was working in the opposite manner. If the option was NOT selected, only the primary bus for a superbus would be monitored. This has been fixed.
    • Oneline Diagrams: When selecting to delete multiple screen layers, only the objects of the first selected layer were being deleted. This has been fixed.
    • Sensitivity Calculations: Fixed a bug calculating the contingent flow on an element for a line closure LCDF calculation when using the LODF calculation dialog when the Near Bus selected was not the line's From Bus. This bug did not affect contingency analysis, ATC, or other calculations where LCDFs are used. It only affected the flow displayed on the LODF dialog.
    • Transient Stability: Fixed bug associated with exciter URST5T wind up limits.
    • Transient Stability: Fixed issue with Vb limit for several exciters.
    • User Interface Dialogs: On the bus and substation dialogs, allow the latitude and longitude values to be deleted.

April 19, 2012

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Can now refer to custom fields (integers, singles, and strings) and calculated fields by name rather than number location of the field. Instead of using variablename:location can now use variablename:name. "BGCalcField:My calculated field name" and "CustomInteger:My custom integer name" are examples. Using this option for custom fields requires that field names be specified using the Custom Field Descriptions.
  • Bug Fixes

    • Contingency Analysis: Using the DCConverter action and attempting to set the power or current setpoint for a voltage controlling converter will do nothing. Previously the voltage setpoint was incorrectly adjusted. If the control mode is changed for one converter from power to current or vice versa, the same change is made for the other converter that is not controlling voltage.
    • File Formats: When loading multi-section lines from a PWB file, custom fields were not being retained and the metered end was not always set correctly. This has been fixed.
    • Oneline Diagrams: When using the Select By Criteria dialog, previously selected layers were not always being retained correctly the next time that you open the dialog. This has been fixed.
    • Oneline Diagrams: An access violation could result when attempting to tap a line connected to at least one substation. This has been fixed.
    • Transient Stability: Fixed bug with setting the filename when using the TSGetResults script command. Instead of using the user-specified filename, the directory would be used instead as the filename.
    • Transient Stability: Fixed memory leak when using the TSGetResults script command or TSGetContingencyResults SimAuto function.
    • User Interface Dialogs: Fixed an access violation that could result when opening any dialog that contains an object chooser.

April 10, 2012

Features and Improvements

  • File Formats: When writing out to EPC files, save to version 18 by default.
  • File Formats: The extra GE EPC fields are now always available with case information displays. The option for the user to specify this has been removed.
  • File Formats: When reading a RAW file, comments for transformer records will now be added to the transformer Memo field.
  • General: Allow the pre-filter option using Area/Zone/Owner filters to be used with Quick Filters.
  • Bug Fixes

    • Contingency Analysis: When running contingency analysis, using a post-contingency auxiliary file, and using Integrated Topology Processing, access violations could result during or following contingency analysis. This has been fixed.
    • Distributed Computation: Fixed a problem with the master instance of distributed contingency analysis where it wouldn't handle errors in remote machines properly, causing Simulator to instantly crash and disappear.
    • Distributed Computation: Reduced memory usage required in distributed contingency analysis by incrementally processing results.
    • File Formats: When appending EPC files that convert switched shunts to fixed shunts or vice versa and an existing shunt is first marked to be deleted and is then replaced with a new shunt, make sure that the Flagged for Delete field is set correctly.
    • File Formats: When saving to EPC version 18 with a switched shunt that was originally identified as SVD type 5, 6, or 7, write out the original befmin and befmax stored with the GE extra data instead of the min and max Mvar of the switched shunt itself.
    • Integrated Topology Processing (ITP): When running contingency analysis, using a post-contingency auxiliary file, and using Integrated Topology Processing, access violations could result during or following contingency analysis. This has been fixed.
    • Oneline Diagrams: When displaying fields on a oneline in italics, some of the text could be clipped. This has been fixed.
    • Oneline Diagrams: Using the substation renumbering tool was breaking the links between the oneline substation objects and data objects. This has been fixed.

April 6, 2012

Features and Improvements

  • Available Transfer Capability (ATC) Tool: Model Conditions and Filters that are part of contingency model criteria used during ATC analysis now allow use of the Model Condition option to Disable if Condition is True in Contingency Reference State.
  • Available Transfer Capability (ATC) Tool: The option to evaluate Model Expressions or fields that are part of contingency actions in the contingency reference state is now used when running ATC analysis.
  • File Formats: When loading an EPC file, the option for using GE Base Load Flag > 0 to prevent Post-CTG response in Simulator will now be used by default.
  • PV and QV Curve (PVQV) Tool: When interpolating inadequate voltages during a PV run, now interpolate if an inadquate voltage occurs at the zero transfer level to determine the negative transfer level at which the voltage becomes inadequate.
  • Bug Fixes

    • File Formats: When reading an EPC file, added checks to automatically ignore implicit generator step-up transformer if the hbus and tbus parameters are not specified.
    • Transient Stability: Fixed potential problem that could occur when multiple events occur at the same time. The network equation Jacobian was not always being rebuilt when it should, resulting in bad solutions.

April 4, 2012

Features and Improvements

  • Case Information Displays: Added Memo field for Model Conditions, Model Filters, and Custom Model Expressions.
  • Fault Analysis: Can now optionally append sequence data when loaded from the Fault Analysis dialog. A prompt will be given to clear all sequence data first or append if opening an auxiliary file or a PTI *.seq file where the *.seq file contains a 0 indicator for new data. If the *.seq file contains a 1 indicating that data should be appended, no prompt is given and the data is just appended.
  • File Formats: When loading in a PTI RAW file or PSLF EPC file, the participation factors of generators are now set to the PMax MW of the unit instead of the generator MVA Base.
  • Oneline Diagrams: Added Center X/Longitude Location and Center Y/Latitude Location fields to the Display Explorer case information displays. These provide the center location of an object. Changing these values will update the X/Longitude and Y/Latitude fields.
  • Bug Fixes

    • PV and QV Curve (PVQV) Tool: When using Integrated Topology Processing, checking for inadequate voltages, and excluding a bus because it is radial, the radial check is now done on the consolidated super bus instead of the original node.
    • Transient Stability: Fixed potential error with initializing temperature control block that is at a limit for GAST2 and GASTWD governors.
    • Transient Stability: For exciter EX2000, added initial limit violation correction for parameter RefLimP.
    • Transient Stability: When converting the CMPLDW model to component parts for use in the power flow, the WSCC dynamics model for the static load component was not being correctly assigned. This has been fixed.
    • Transient Stability: Fixed a List Out of Bounds error that could occur when running transient stability analysis with a case that contains more than one multi-terminal DC line.

March 22, 2012

Features and Improvements

  • Bus View and Substation View Onelines: Modified the option for showing field labels so that it shows the column heading text of the field because this is much shorter.
  • File Formats: Modified reading of the hdbexport CSV file to better handle records indices which are skipped.
  • File Formats: When reading an EPC file and writing a message regarding a bypassed branch record we include R, X, and B values in the log message.
  • Transient Stability: Modified showing of Results from RAM to better show results for multiple contingencies.
  • Transient Stability: Modified the reading/writing of the WT3G and WT4G models from a DYD file so it read the Khv and Iolim fields. These fields are not used by Simulator, but that are read gracefully and written back out as well.
  • Transient Stability: Modified the reading/writing of the WT3G and WT4G models from a DYD file so it read the Td field and uses it appropriately.
  • Transient Stability: Modified the reading/writing of the WT4E model from a DYD file so it reads the ImaxTD and Viqlim parameters. Previously these were hard-coded to 1.7 and 1.6 always.
  • Bug Fixes

    • Transient Stability: Modified reading the PTI DYR file so that it handles models written across multiple lines of a text file. Also modified so that we ignore an extra comma at the end of a DYR record.
    • Transient Stability: Fixed an error in the AC7B exciter model with an incorrect sign on the derivative feedback block.

March 14, 2012

Features and Improvements

  • General: The substation for three-winding transformer star buses is automatically set to the same substation as the primary winding bus. The substation of the star bus cannot be edited by the user.
  • Bug Fixes

    • General: Access violation could occur when unlocking the software. This has been fixed.
    • Transient Stability: Allow TSR File Archiving to work again.
    • Transient Stability: Bug fix in March 7, 2012 patch to force abort when running out of hard drive space was transient stability run to NOT abort in other situations that required it to abort. This has been fixed.

March 13, 2012

Features and Improvements

  • Contingency Analysis Tool: Now allow contingencies to be monitored as part of a Custom Monitor. Only the contingency fields for the contingency itself can be monitored for a given contingency.
  • Transient Stability: Added option on the Results from RAM tab to Show Multiple Contingencies Events when Multiple Contingencies are being processed. If this option is checked, results for all contingencies will be shown in the Minimum/Maximum Values, Events, and Solution Details tabs.
  • Transient Stability: Added Clear Results in RAM button on the Results from RAM tab. Clicking this will clear all of the results in Time Values.
  • Bug Fixes

    • Case Information Displays: Fixed error when displaying some information for line shunts. The data was stored correctly, but some data could show up as blank in the case information display.
    • General: Fixed errors when merging multi-section line sections. Extra line shunts were being created. The sum of the line shunts was correct, but there were too many individual line shunts. Only a single line shunt should exist at either or both ends of the merged line.
    • Oneline Diagrams: Fixed an access violation that could occur when opening the Custom Hint Values dialog.

March 9, 2012

Features and Improvements

  • Case Information Displays: Added Online field for dc lines and VSC dc lines.
  • Case Information Displays: Added Derived Online field for branches, dc lines, and VSC dc lines. If Online = NO then Derived Online = OPEN, else Derived Online = Derived Status.
  • Transient Stability: When choosing to begin checking for Limit Monitors Results after the last event, now have an option to specify a time delay after the last event at which to start checking.

March 7, 2012

Features and Improvements

  • Case Information Displays: Changed how Derived Status is determined. If Status = OPEN then Derived Status = OPEN else if breaker then Derived Status = CLOSED. If non-breaker shunt device (gen, load, or switched shunt) and a closed breaker is found by looking outward from the device terminal, a device is considered to be CLOSED. For a non-breaker branch, look from both terminals to determine if CLOSED, OPEN (no closed breaker at either terminal), OPEN FROM (closed breaker at to terminal only), or OPEN TO (closed breaker at from terminal only). Encountering a shunt device (gen, load, or switched shunt) when examining a branch will be considered the same as finding a closed breaker.
  • Case Information Displays: Added ability to show substation latitude and longitude with generators, loads, and switched shunts.
  • Bug Fixes

    • Transient Stability: Modified saving of transient results to hard drive so that if not enough hard drive space exists, the simulation gracefully aborts and an appropriate error message is shown.
    • Transient Stability: When saving all two bus equivalent cases now just save one generator at a bus.
    • Transient Stability: Fixed errors with how line relay models are read and written to DYD files when they are linked to multi-section lines.
    • Transient Stability: Added ability to specify the "Device Location" for a line relay model in an AUX file.
    • Transient Stability: TLIN1 relay model would cause a fatal error if the relay actually attempted to operate. This has been fixed.
    • Transient Stability: Fixed an infinite loop that would result if attempting to edit Transient Limit Monitor data directly in the case information table.

February 28, 2012

Bug Fixes

  • File Formats: Additional problems have been encountered with the Long_ID fields for transformers containing invalid characters in an EPC file. Include some additional checks to try to prevent problems from these characters or write error messages to the log if the errors have not been handled and we end up not reading the remainder of the transformer data section.
  • File Formats: When reading in DC lines in a RAW file, both identifying by number and name is now allowed if the RAW file version is less than version 31.
  • Transient Stability: Fixed a bug with the MVA base When using the option to convert CMPLDW model to component parts. This could result in loads being initialized as negative when they should be positive.
  • Transient Stability: There were errors implementing transient contingencies that opened either the near or far end of a line. These have been fixed.

February 27, 2012

Features and Improvements

  • Simulator Automation Server (SimAuto): The OpenOneline script command can be now be used to open onelines and associate them with a case even though the onelines cannot be viewed while running SimAuto. When a case is saved using SimAuto after onelines have been opened, the onelines will also be opened along with the case when the case is opened through the GUI.
  • Transient Stability: When creating a two bus equivalent case, set the option for Save Results Every n Timesteps to 1.
  • Bug Fixes

    • PV and QV Curve (PVQV) Tool: When saving QV results to file, some of the header and scenario information was corrupted. This has been fixed.
    • Transient Stability: Fixed access violation that could occur when using the LD1PAC model.

February 23, 2012

Features and Improvements

  • Transient Stability: Added option to save ALL of the two bus equivalents.
  • Bug Fixes

    • Transient Stability: A transient contingency to close a switched shunt would not actually close the shunt. This has been fixed.
    • User Interface Dialogs: When opening various dialogs, there may have been a flicker due to the dialog being created and filled with content. This flicker has been corrected.

February 21, 2012

Bug Fixes

  • PV and QV Curve (PVQV) Tool: When enforcing MW limits with the ramping, it was possible that the source or sink could hit a min or max limit and the ramping would continue. This would result in the portion of the ramping that occurs after the limit is hit going to the system slack instead of the injection group that is at a limit. This problem would only occur if at least one generator in the affected injection group was within a very small tolerance of its limit in the base case. This has been fixed.

February 15, 2012

Features and Improvements

  • Oneline Diagrams: When specifying a Stub Size of 0 with Default Drawing Values for transmission lines, auto-inserted lines will be spaced appropriately at the bus instead of all being drawn from the middle of the bus.
  • Transient Stability: Added option for Time to Begin Checking for Limit Monitors Results. This impacts when Transient Limit Monitors are actually monitored. Previously, Simulator would beginning monitoring these after the last event. Now the user can select to start monitoring after the last event, immediately at the start of the run, or at a custom time in seconds.
  • Bug Fixes

    • File Formats: When loading the Areva hdbexport CSV file, CBType mapping was not working correctly. This has been fixed.
    • File Formats: When loading in an EPC version 18 file with SVD data, fixed an error that was incorrectly loading the new fields in version 18.
    • File Formats: When loading in an EPC file with strange characters in the Long ID field for transformers, correctly handle these characters so that the entire file is loaded.
    • Oneline Diagrams: Fixed an access violation that could occur when modifying onelines via various display object dialog boxes.
    • Sensitivity Calculations: When using the Advanced LODF Calculation, memory errors could result if monitoring a large number of branches and outaging a large number of branches. This has been fixed.
    • Transient Stability: When loading in an auxiliary file with Transient Stability Contingencies, the Model Criteria was not getting populated correctly. This has been fixed.
    • Transient Stability: After applying a fault on a device if a second fault was applied on the same device Simulator attempted to add the fault admittances together to model two simultaneous faults. This is of limited use, so Simulator has been changed to replace the existing fault (including admittance/impedance or fault location on a branch).

February 3, 2012

Features and Improvements

  • File Formats: When loading in an auxiliary file, read the switched shunt regulation type field before the regulation range values because the regulation type will determine the units of the regulation range.
  • General: Added more circular reference checking for Model Conditions, Model Filters, and Model Expressions.
  • Oneline Diagrams: Added option in Simulator Options under Onelines --> Files --> Open Oneline Links By to specify if oneline links are to be opened by Number, Name_kV, or Label.
  • PV and QV Curve (PVQV) Tool: Model Conditions and Filters that are part of contingency model criteria used during PV and QV analysis now allow use of the Model Condition option to Disable if Condition is True in Contingency Reference State.
  • Transient Stability: Added a Transient Contingency option to set the per-unit resistance and reactance of an AC line or transformer.
  • Bug Fixes

    • Case Information Displays: The option to visualize the Model Filter logic has been moved from the local menu under Insert Filter Logic to Model Filter Records --> Visualize Filter Logic.
    • Distributed Computation: Fixed "invalid variant type" errors that would occur during distributed ATC. This was caused by Simulator attempting to distribute setup information that doesn't exist, i.e. blank extra monitors or interface rating scenarios. Simulator no longer attempts to send this information.
    • General: When visualizing Model Filter logic and a circular reference is found, a graphical indication of the circular reference will be presented instead of a logic diagram.
    • Oneline Diagrams: The ability to scroll and zoom on a oneline diagram could be lost after a message dialog appeared. This has been fixed.
    • Power Flow Solution: It was possible for a generator that was not initially on AVR control to get pegged at a Mvar limit and never be allowed to move from the limit if it was set on AVR control. This has been fixed. This fix is related to the fix that was made with the Jan. 25, 2012 patch also related to generators being set at Mvar limits.
    • Time Step Simulation: Fixed a bug that would not apply custom input values for buses.
    • Transient Stability: Corrected LCFB1_PTI input parameters.
    • Transient Stability: Fixed bug with EXAC3 in which initial Va limits were being modified based on the value of Vr. Now we use Va.
    • User Interface Dialogs: When using the chooser display available on many dialogs to pick an object, switching between identifying the object by Name, Number, or Label should now keep the same object selected regardless of how it is being identified.

January 25, 2012

Features and Improvements

  • General: In the Model Filter Visualization, the text of the conditions and filters are now always black instead of using multiple colors to match the same conditions and filters.
  • Oneline Diagrams: Added a shortcut with Line Flow Arrows to toggle the position of the text above and below the arrow. When the object is selected, Ctrl-D will toggle the text position.
  • Bug Fixes

    • Contingency Analysis: When using the linear calculation method or full dc analysis, flows on interfaces containing branches with weighting factors other than 1 were not being calculated correctly. This has been fixed.
    • File Formats: Fixed access violation that could occur when opening a PWB file created with old Simulator versions prior to version 11 and the case contained transactions between areas.
    • File Formats: Fixed an access violation that could occur when saving a PWB file and model expressions contain unlinked variables.
    • General: When equivalencing a case and choosing to convert shunts to loads, shunts could still result. This would occur when one of a phase shifter's terminals was in the study system and the other was in the external system. The bus not being equivalenced would have a shunt value and an equivalent load created. The sum of these was correct, but the allocation between the two was not. This has been fixed.
    • Oneline Diagrams: In the custom color map that can be defined for contours, the Transparency field was backwards with NO meaning not transparent instead of YES. This has been fixed.
    • Power Flow Solution: When loading in a case, it was possible that the Mvar output of a generator was not set exactly to one of the limits when the unit was marked as being at a limit. This would prevent the unit from ever moving even if it had range to move. This has been fixed.
    • User Interface Dialogs: Increased the number of decimal places shown from 1 to 3 for the reactive capability curve points on the generator dialog.

January 13, 2012

Bug Fixes

  • File Formats: Under extremely rare circumstances a PWB file could be corrupted when writing. This could only happen if customized bus view options or customized sets of oneline display options had been created.

January 12, 2012

Features and Improvements

  • Contingency Analysis Tool: When using a Model Expression or Field to determine the Amount for the Action Type of a contingency action, a new option to Evaluate in the REference State has been added. When this option is in use the Amount will be determined from the reference state rather than the present contingency state.
  • Contingency Analysis Tool: A new option is available with Model Conditions to Disable if Condition is True in Contingency Reference State. A Model Filter will be disabled if all of its conditions are using this option and they evaluate to true in the contingency reference state. A Model Criteria that uses a Model Condition or Model Filter that has been disabled will not cause a contingency action to be implemented. A Model Filter will ignore any Model Conditions that have been disabled.
  • Contingency Analysis Tool: A new contingency action Status, TOPOLOGYCHECK, has been added. Any Model Criteria using this status will be evaluated, and if true the action will be implemented, after any CHECK actions and unconditional actions have been implemented but before the power flow is solved.
    Contingency Analysis: DC Converter contingency actions have been added.
  • File Formats: Modified to add additional branch labels when reading Areva CSV file.
  • General: Model Expressions now allow the use of Model Conditions and Model Filters.
  • User Interface Dialogs: Allow voltage profile viewing of branches identified as breakers.
  • Bug Fixes

    • File Formats: Modified the EPC version 18 format written from Simulator to more closely match the PSLF EPC written format.
    • General: When double-clicking on a PWB file and opening Simulator, Simulator would fail to open a file if the filename contained successive spaces. This problem can be fixed by reinstalling Simulator from the installation file provided with the latest patch.
    • Power Flow Solution: Fixed some errors that could occur when using line tapping in conjunction with lines marked as any of the zero impedance device types such as Breaker, Disconnect, ZBR, etc.
    • Simulator Automation Server (SimAuto): Fixed an access violation that could occur when using the SimAuto function TSGetContingencyResults. This bug might simply cause an application to freeze or cause an error.
    • Transient Stability: Fixed an access violation that could occur when using the SimAuto function TSGetContingencyResults. This bug might simply cause an application to freeze or cause an error.

January 6, 2012

Bug Fixes

  • Integrated Topology Processing (ITP): Fixed a bug that could move devices from their original buses to their pnodes following consolidation and deconsolidation.

January 3, 2012

Features and Improvements

  • Transient Stability: When converting composite load models (CMPLDW) to component parts, now have options for specifying whether the transformer or feeder will be added if impedances are zero. If they should be added, also have option to specify the non-zero impedances.
  • Transient Stability: Added stabilizer output voltage to the Minimum/Maximum Values results table.
  • Transient Stability: Added support for gain parameter Kdrp with machine model LCFB1.
  • Bug Fixes

    • Contingency Analysis: Fixed a bug that would not allow the contingency specific solution options to load via an auxiliary file.
    • Power Flow Solution: Fixed an access violation that could occur when solving the power flow after appending the case with a new closed branch.
    • PV and QV Curve (PVQV) Tool: Fixed a bug that would not allow the QV specific solution options to load via an auxiliary file.
    • Transient Stability: Fixed a problem that would not allow the block diagrams to load into Acrobat.
    • Transient Stability: Models with blank IDs will be ignored.
    • Transient Stability: Fixed bug in creating SMIB for multiple generator buses.
    • Transient Stability: Fixed bug in ESAC7B in which Va was being multiplied by the compensated terminal voltage rather than the terminal voltage.
    • Transient Stability: GENTPF/GENTPJ and GENCC ignore speed effects in the generator stator voltages.
    • Transient Stability: Modified determination of fsrt for GGOV3 and corrected bug in which (1,1) point wasn't being added to GV/PGV curves for hydro units.
    • Transient Stability: Modified GENTPF so saturation is considered on the q-axis for case with Tqop = 0.
    • Transient Stability: Fixed bug in which the wrong exciter saturation curve was being used sometimes if E2 < E1.

December 21, 2011

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added new DATA object, DefDrawOneline, that will allow changing the default font (name, size, color, and style), option to use the default font size for all new text fields, and the default background color for oneline diagrams via an auxiliary file.
  • Case Information Displays: Allow advanced filtering on the Modify/Create Limit Groups table of the Limit Monitoring Settings and Violations dialog. This also affects the LimitSet data object when using scripts.
  • Case Information Displays: Added transformer fields on the transformer base to the Difference Flows base case to that they can be properly compared.
  • Power Flow Solution: Added VSC DC Line state to the system state that is used for restoring the last successful solution or state before a failed solution along with the contingency analysis, PVQV, ATC, and other reference states.
  • Transient Stability: Added option to allow conversion of the composite load model (CMPLDW) to component parts for use in the power flow.
  • Transient Stability: Added Alarm field to OEL1 model.
  • Transient Stability: Added option to not flip machine saturation values when S12 < S1.
  • User Interface Dialogs: Moved the option "Disable Transformer Tap Control if Tap Sens. is the Wrong Sign" from the Common Options to the Advanced Options tab of the Power Flow Solution options.
  • Bug Fixes

    • Case Information Displays: Fixed a bug that would not allow a switched shunt to be created when pasting from Excel. The error indicated that all required fields were not present even though they were.
    • Contingency Analysis: Fixed some bugs that would cause the Make-up Power grid on the Contingency Analysis dialog not to refresh correctly.
    • Contingency Analysis: Fixed a bug that would change to the Results page on the Contingency Analysis dialog when making changes to other pages on the dialog.
    • Contingency Analysis: Fixed a bug that would not show the entire description of What Actually Occurred on the Applied and Skipped Actions dialog.
    • Distributed Computation: Fixed a bug that would cause authentication to fail when setting up the list of computers to use with Distributed Computing.
    • Oneline Diagrams: Fixed a bug where the default oneline background color was not always updating properly.
    • Optimal Power Flow (OPF): Fixed bug that would not show the OPF Options and Results dialog the first time that it is opened.
    • Sensitivity Calculations: When calculating with Multiple Elements on the TLR Sensitivities form, the "Clear before Calculate" option is always set.
    • Time Step Simulation: Fixed a bug that would produce an out of memory error when reading TSB files saved in version 15 or earlier of Simulator.
    • Transient Stability: When loading in a GE DYD file, there is no longer the requirement that exciters be read before stabilizers.
    • Transient Stability: Fixed reading in the GENCLS_PLAYBACK model from a GE DYD file.
    • Transient Stability: Replace double quotes in the invocation section (identifier before the colon) of a GE DYD file with single quotes to handle bad file formats.
    • Transient Stability: Corrected reading of the CMPLDW model so that the mvabase is read and stored.
    • Transient Stability: Fixed writing IEEEG1_GE and ESST1A_GE to GE DYD file.
    • Transient Stability: Modified handling of mechanical torque's speed dependence for MOTORW.
    • Transient Stability: Fixed bug with EXAC8B correctly handling scaled Vrmin/Vrmax limits when Ta=0.
    • Transient Stability: on ESAC7B set Vfemax to a minimum of 3 if it is greater than 0 and less than 3.
    • Transient Stability: Added SMVABase parameter for CMPLDW.
    • User Interface Dialogs: On the Branch Information dialog, show the impedances with 6 decimal places rather than 5. This fixes some potential issues when changing transformer base parameters.

December 8, 2011

Features and Improvements

  • Transient Stability: Added support for line relays to have knowledge of which end of the line they refer to.
  • Transient Stability: Implemented TLIN1 relay.
  • Transient Stability: Added some Other Fields for ESAC8B.
  • Bug Fixes

    • Contingency Analysis: Fixed WhatActuallyOccurred so it makes sense with the use of dc power flow contingency analysis.
    • Power Flow Solution: Fixed potential power flow failure caused by multiple switched shunt regulating the same bus in a coordinated manner. This feature was new in Version 16 and did not work properly in all circumstances.
    • Transient Stability: Fixed bug in setting Vsmin limit for WSCCST stabilizer when Vslow = 0.
    • Transient Stability: Modified WSCCST so if Input Signal Code = 0 there is no input.

September 14, 2010

Bug Fixes

  • Transient Stability: Fixed error in induction motor saturation modeling introduced in September 13 patch.

September 13, 2010

Bug Fixes

  • Transient Stability: The initialization process for a load which was out-of-service in the power flow case was preventing that load from being closed in during the transient contingency simulation. This has been fixed.
  • User Interface Dialogs: When converting a transformer to a branch on the Branch Edit Mode dialog, we now delete any three-winding transformer to which the transformer belongs.

September 10, 2010

Features and Improvements

  • Available Transfer Capability (ATC) Tool: Modified internal numerical routines to make them faster.
  • Sensitivity Calculations: Modified internal numerical routines to make solutions faster.
  • Bug Fixes

    • Integrated Topology Processing (ITP): Fixed a potential issue with restoring states when using consolidation related to a generator's regulated bus number.
    • Oneline Diagrams: Fixed a oneline "flicker" that could occur when using the line navigation arrows.
    • Oneline Diagrams: The 3D oneline options were not available when right-clicking on a oneline diagram in 3D mode. This has been fixed.
    • Power Flow Solution: Presently Switched Shunts can not be on continuous control in the inner power flow loop if they are at a bus that is being regulated by generators remotedly. An error check prevents this now.
    • Power Flow Solution: Fixed a situation where a phase or tap were not being brought back within the Min/Max Tap (or phase) range when enabling a transformer for control which started outside of its allow range. It will now be properly set to be within range.
    • Power Flow Solution: When using the robust solution process, solve the full newton at the end of the process even if the previous solution failed. The previous failed solution may have been from the decoupled power flow and the full newton might converge. Solves a problem encountered with WECC cases.
    • Time Step Simulation: Fixed error with creating time step actions which change the generator voltage setpoint.
    • Transient Stability: The initialization process for a load which was out-of-service in the power flow case was preventing that load from being closed in during the transient contingency simulation. This has been fixed.

September 2, 2010

Features and Improvements

  • File Formats: Added a log warning message when appending an EPC file which causes a transformer branch to be converted to a normal branch.
  • Transient Stability: Added ability when reading an EXWTGE wind electrical model from a GE DYD file to detect if the EXWTGE record represents an older version of that records format. The EXWTGE record is then read using the older parameter order.
  • Transient Stability: Added full support for the LDFR load characteristic model.
  • Transient Stability: Added read/write support for the CSTATT model.
  • Bug Fixes

    • Available Transfer Capability (ATC) Tool: Fixed an error that could occur when running an iterated ATC simulation that involved conditional contingency elements.
    • Oneline Diagrams: Fixed access violation that could occur when auto-inserting buses objects using the substation record's latitude/longitude information. An error could occur if not all buses were assigned to a substation.
    • Power Flow Solution: Fixed a bug which could cause solution convergence difficulty when allowed discrete switched shunts to switch in the inner power flow loop.
    • Transient Stability: Fixed problem with the default numeric format used for showing axis label values.
    • Transient Stability: Fixed bug with using the Initialize Reference Angle At Zero option. The bus frequency measurements were not being initialized correctly in these situations which could cause errors in the initial frequencies and also cause problems due to stabilizer feedbacks.
    • Transient Stability: Fixed error in initialization of REX exciter model when Xc <> 0.
    • QV Curve Tool: Modified qvExtraMonitoring file so that the results can be easily identified by the contingency and bus which created the results.