What's in the Simulator 15 Patch?

Select one of the following links to view descriptions of the changes incorporated via the PowerWorld Simulator Patch files

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June 25, 2010

New Features

• File Formats: When using the Present Topological Differences from Base Case tool, added the ability to save the removed elements in the EPC file format using status values of -4.
• Oneline Diagrams: When using a contour with a dynamic interpretation, if all the values being contoured had the same value the contour image could appear random. This was remedied by enforcing a minimum tolerance on the separation between minimum, nominal, and maximum values of the color map.
• Transient Stability: Modified storage to RAM to automatically include any information needed for a subplot's horizontal axis data.
• User Interface Dialogs: Added ability to assign Case Comments to a case which designate a person's name and a time along with the comment. These are only stored in the PWB file format.

Bug Fixes

• Fault Analysis: Fixed error with the handling of out-of-service switched shunt when using the IEC-909 fault calculation
• Oneline Diagrams: On the contour dialog, the choice of interpretation was not being saved properly to a PWD file. Thus when the diagram was reopened the choice was not retained. This has been fixed.
• Power Flow Solution: Fixed error in handling of phase shifters in the DC approximation solution.
• QV Curve Tool: Removed irrelevant message dialog when saving QV results to an AUX file. This occurred for QV curves involving a contingency which could not be solved.
• Time Step Simulation: Fixed problem when pasting injection group data from Excel into time step simulation input.
• Transient Stability: Modified storage of Transient Contingencies to an AUX file to properly use number identifiers when appropriate.
• Transient Stability: Fixed error in initializing the SMIB calculation to properly handle a generator that was de-energized.
• Transient Stability: When storing data to Hard-Drive while using the Integrated Topology Processing, information is now stored using the full-topology bus number identifiers so that they can be properly read back in.
• Transient Stability: Fixed error in handling of Generic Limit Monitors looking at over frequency for synchronous generators.  The action to take was not being properly interpreted.
• User Interface Dialogs: Fixed multi-section line dialog bug. The Find From Bus button did not work when inserting a new MS Line.

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June 28, 2010

New Features

• None.

Bug Fixes

• Help: Added help files and block diagrams to the PowerWorld documents download page here.

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July 2, 2010

New Features

• PV Curve Tool: With the PV tool added the options to interpolate inadequate voltages and to always report the minimum voltage when monitoring low limit violations even if no limits are violated.

Bug Fixes

• Time Step Simulation: Fixed bug with deleting columns from injection group inputs.
• Time Step Simulation: Fixed problem with scaling load with injection group inputs.
• Time Step Simulation: Fixed ability to defined load fields as part of result tracking.

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July 7, 2010

New Features

• Case Information Displays: Added ability to use other object type filters with the GenVarLim object.
• File Formats: When loading the hdbexport file, modified to automatically add two labels to each transmission line. One label starts with the "from" substation name and the other label starts with the "to" substation name.
• Transient Stability: Added support for storing interface MW, Mvar, and MVA flows as part of the transient stability results.
• Transient Stability: Added ability to show the number of elements in a Transient Contingency.
• Transient Stability: Modified the Transient Contingency Element Dialog to show the filter information for choosing the object by default.

Bug Fixes

• Contingency Analysis: Fixed bug that would prevent creating the following object types from an Auxiliary File or by copy/paste from a spreadsheet: ContingencyElement, CTGElementBlockElement, GlobalContingencyActionsElement, PostPowerFlowActionsElement.
• Oneline Diagrams: Fixed flashing hint windows caused by interaction between navigation arrows and oneline hints.
• Transient Stability: Fixed bug with writing TSR files. The bug was introduced in July 2 patch.
• Transient Stability: Some problems with access violations when running stability were encountered related to the plot designer. These should be fixed now.
• Transient Stability: When auto-correcting the Xl value for a GENSAL, GENROU, or other synchronous machine model, the informational message had a typo indicating it was changing Xqp. This typo has been fixed.
• Transient Stability: The auto-correction routine was not allowing the Linc value of a GAST_GE model to be near zero. This restriction has been removed.

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July 9, 2010

New Features

• Auxiliary File: Added new script command "AutoInsertTieLineTransactions" which takes now parameters. This deletes all existing MW transactions and set the unspecified MW interchange for each area to zero. It then automatically creates a MW transaction between each pair of connected areas with a MW transaction exactly equal to the sum of the tie-line flows.
• File Formats: Modified the writing of PTI RAW files so that switched shunt records always write out at least one block. If none exists, a single block with 1 step and size equal to the present MVar output is written.
• File Formats: Modified the writing of GE EPC file so that Multi-Terminal DC converters will write out the "aloss" parameter in a manner consistent with how the EPCL file mtTAP.p expects to ensure the EPCL operates appropriate for WECC data files.
• User Interface Dialogs: On the Present Topological Differences from Base Case dialog, the various case information displays of removed elements have been modified to provide a mechanism to right-click on a selection and choose to Save Selected to EPC file.

Bug Fixes

• File Formats: When saving any file, Simulator was prompting the user about adding a comment to the file. This will now only be done when saving to the most recent PWB file format.
• Power Flow Solution: Fixed error caused when a MTDC Converter ended up with a current flow of exactly 0.0 amps. This resulted in a number being equal to 0/0 which resulted in a "NAN" result causing the power flow to fail.
• User Interface Dialogs: Fixed error in feature to remove additional GE EPC data from the case.

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July 16, 2010

New Features

• Oneline Diagrams: Added a Simulator Oneline option that alter how Simulator responds when click on a circuit breaker symbol for a generator display object. Normally the generator's status is set to closed and the MW value is reset to its previous value. The new option allows the value to be set to its minimum MW output instead.
• Transient Stability: Modified the Generator and Load dialogs to be sizeable when on the Transient Stability Tab.
• Transient Stability: Modified the Plot Designer portion of the dialog to have scroll bars
• Transient Stability: Added the ability to add to a Plot a Title Block including an image logo, text, and a date.
• Transient Stability: Added ability to copy to clipboard or print a plot including the Title Block and multiple subplots.
• Transient Stability: Added ability to close all open plots from the local menu of a plot and from a button on the Transient Stability dialog.
• Transient Stability: Modified GENCC generators to require an Xcomp value which is negative.
• Transient Stability: Modified the loading of GE DYD files to also accept a file extension of "DYC". When loading a DYC file no prompt will appear asking about deleting existing stability models. The assumption is that it will append to existing models.

Bug Fixes

• File Formats: When appending a case using a RAW or an EPC file, set the area and zone numbers for loads. Previously these were not updated when appending.
• File Formats: Fixed error that would occur if choosing to save out an EPC file and then hitting cancel.
• QV Curves: Added more error handling when saving the tracking results file in the QV curve. This should help prevent process failures when the file network location is unavailable.

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July 23, 2010

New Features

• Sensitivity Calculations: Greatly increased the speed of calculating multiple element TLR sensitivities.

Bug Fixes

• Auxiliary File Format: Fixed access violation caused when calling MergeLineTerminals() with no branches actually meeting the filter. This will now simply do nothing instead.
• File Formats: Fixed potential error when reading an PTI *.seq file for sequence data. It was possible for the transformer zero sequence impedance to not properly read from this file.
• PV Curve Tool: Fixed problem with plotting base case values on the horizontal axis. Need to determine plot points based on a common nominal shift and can't assume that there will be the same number of points in a scenario and the base case results.
• Oneline Diagrams: Fixed error with anchoring of transmission line objects after saving some oneline diagrams.
• Transient Stability: Fixed error when plotting either 7 or 10 subplots on a single plot. The subplots were not laid out properly.

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August 4, 2010

New Features

• Auxiliary Script: When using the MergeLineTerminals() script command, we now send a message to the log if no lines are actually selected for merging.
• QV Curves: When exporting QV results to a CSV file, all results are now sorted by the voltage setpoint.
• Transient Stability: When loading in synchronous machine saturation values specified at 1.0 and 1.2 per unit, if S(1.2) < S(1.0) then Simulator will flip the values to autocorrect.

Bug Fixes

• File Formats: When writing out the internal generator R and X values to a RAW file, an old limitation existed preventing values larger than 999. This limitation has been removed.
• File Formats: When loading text files, modified to treat TAB characters identically to SPACE characters.
• File Formats: When appending to a case (from an EPC, RAW, or PWB file) if the From and To designations of a branch are backwards in the appending file, then the designations will now be flipped as part of the appending processes.
• Oneline Diagrams: Changed the icon size for the end of transmission lines to be smaller when exporting to a KML file.
• Power Flow Solution: When calculating the flow on a branch after solving a DC power flow, the contribution of MW Line Shunts was not properly handled. The actually DC power flow solution was correct, but the line flow would not be correct. This has been fixed.
• Sensitivities: Fixed bug in the LODF calculations introduced in the July 23 patch.
• Time Step Simulation: Fixed bug with writing out injection group CSV files that would add the date and time to the file twice. This would also have affected the switched shunt CSV files.
• Time Step Simulation: Added scroll box around options on the Time Step Simulation dialog.
• Transient Stability: Fixed a bug where trying to show a plot at the execution of transient stability. The plots were shown but never properly refreshed.
• Transient Stability: Modified so that the generator internal R and X values are always updated to match the generator subtransient or transient impedances as appropriate. This is done when the stability is either solved or when the stability data is loaded or stored. These fields must match and the stability data exported to other software must reflect the fact that Simulator always uses the data specified with machine models.
• Transient Stability: Fixed a bug in how the saturation of GENROU and GENSAE models was handled.

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August 11, 2010

New Features

• Auxiliary Files: Added a new script command "InjectionGroupsAutoInsert;". This passes no parameters. The options for this command can be set by populating the object "IG_AutoInsert_Options" appropriately. The settings available with this object represent what is seen on the Auto Insert Injection Groups Dialog.
• Available Transfer Capability: Optimized the code for the calculate of ATC values to pre-calculate the Line Outage/Insertion sensitivities prior to running the ATC. This increased the speed of the single linear step ATC method by about a factor of 2. Increases the total speed of the iterated methods by about a factor of 3.
• Case Information Displays: Add ability to define "Custom String Expressions" which represent the concatenation of strings from the columns of an object. Included in the was a new function available in the expression string with format "Str(x1, minlength, decimals)" where x1 represents a numeric variable, minlength represents the minimum number of characters for the result, and decimals represents the number of characters to the right of the decimal point.
• File Formats: When reading from an EPC file, added the reading of the area and zone designation of a GE branch and transformer. This will not be stored in the PWB file format for now but will be added to Version 16's format.
• Oneline Diagrams: When changing to a Saved View which specifies that a contour be shown, we now automatically refresh the contour image.
• User Interface: On the Auto-Insert Injection Groups Dialog, add an option to name an injection group by a specific name. This will only be used if only ONE injection group ends up being created based on the other options. The intent is to use this in conjunction with the new scrip command "InjectionGroupsAutoInsert;".
• Transient Stability: When writing out DYD files, we now always write out the model names in lower case characters.
• Transient Stability: When write out two bus equivalent models from the SMIB portion of the dialog, generators are now automatically set to AVR = NO.
• Transient Stability: Modified to automatically refresh any open plots when performing the interval check while running transient stability. Previously it would only refresh plots if the option was set to "Transfer Results to Power Flow after Interval Check"
• Transient Stability: Modified the user interface throughout Simulator to not allow editing of the power system data when you've transferred the transient stability state over to the power flow. Case Information displays will appear yellowed and editing on most power system model dialogs will not be allowed.
• Transient Stability: Added ability to open only one end of a transmission branch.
• Transient Stability: Fixed bug when using the default (done by specifying a negative gv1 value) non-linear steam gate function for the IEEEG1 governor.

Bug Fixes

• Contingency Analysis: Fixed a potential error that could occur if PostCheck contingency actions were used in combination with the "Solve Power Flow" contingency action.
• Contingency Analysis: When specifying a Post-Contingency AUX file which does not exist on your computer, Simulator is supposed to show a dialog telling you this and then abort the contingency simulation. This was not working properly and error was appearing saying "Cannot focus a disable or invisible window.". This error has been fixed.
• File Formats: When writing out the DC converters for a multi-terminal line to an EPC file, Simulator write out modes of 0, 4, or 5 if the multi-terminal DC line had only 2 converters (similar to what is done for the Two-Terminal DC lines). This was reported as causing problem when reading into GE, so we now will write only 1, 2, or 3 instead.
• Oneline Diagram: When switching to a Saved View which specified that no contour should be shown, the contour was not properly removed. This has been fixed.
• Transient Stability: Modified to better handle the saturation of the GENTPF and GENTPJ generator models
• User Interface: Removed old options to "automatically open overheated lines during simulation".

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August 12, 2010

New Features

• QV Curves: Added the ability to plot multiple QV curves on the same plot.

Bug Fixes

• Distributed Computation: Continued stability improvements for the distributed computation add-ons.

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August 24, 2010

New Features

• PV Curve Tool: The more flexible plotting environment available in Transient Stability has been integrated into the PV Curve tool. This is available under "New Plots" on the PV Curve dialog. Note that this is available in addition to the previous plotting tool.
• Transient Stability: For the IEEEG1 governor model, the following two relationship must be true. K1+K3+K5+K7=1 and K2+K4+K6+K8=1. If they are not true, Simulator will now normalize the values to enforce these equalities.
• Transient Stability: When choosing to show a transient stability plot on the execution of the stability run, the simulation will now automatically update the plots with appropriate data after each interval check. Previously the user would also have to specify this update if they want the plots to actually show data.

Bug Fixes

• Available Transfer Capability: Corrected loading in transfer limiters from an aux file when they are processed for only a single run and not for multiple scenarios.
• Power Flow Solution: Fixed improper handling of magnetizing conductance in some locations when using the DC power flow approximation.
• Transient Stability: Fixed an incorrect choice in the choices appear in the Toggle Drop-Down for generator objects's Governor Response Limits.
• Transient Stability: Fixed typo for the column heading which mixed up the K1 and K2 parameters for the IEE2ST stabilizer.
• Transient Stability: Fixed the running of multiple transient contingencies to obey the SKIP field of a transient contingency. Previously we were always running all the transient contingencies. It will now skip them as specified.
• Transient Stability: For some generators there were hard limits on the value of H, D, Tdo, Tdop, and the Saturation values. These limits previously were auto-corrected but have been changed to leave the values and only create a warning.

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August 30, 2010

New Features

• Oneline Diagrams: Added ability to export a oneline diagram as a GIF image.
• Oneline Diagrams: Added ability to export a oneline diagram as an animated GIF image (animated the arrows and generator rotors).
• Transient Stability: Added toolbars to the generator's SMIB dialog which shows details on the generator eigenvalues.
• Transient Stability: Modified the labels on the axis to change format by default as appropriate. Thus if the absolute value of minimum and maximum values are both less than 0.01 it will automatically switch to scientific notation. This will also happen if both min/max are either greater than 10,000 or less than -10,000.
• Transient Stability: Added ability to store results for the apparent power at the from and to ends of a branch.
• Transient Stability: When choosing to store results to the Hard Drive, previously if no directory was specified to which results should be saved then results would not be saved to hard drive at all. Now if the directory is blank, Simulator will default to save data in the same directory as the case was loaded from. Note that if an invalid directory is specified it will still not save results.
• Transient Stability: Modified the generator fields for Maximum Frequency and Minimum Frequency to show actual frequency instead of the deviation from nominal.

Bug Fixes

• Contingency Analysis: Fixed potential access violation when using Advanced Limit Monitoring to look for voltage deviation violation in percentage instead of per unit.
• Distributed Computing: Under some circumstances, distributed computation could freeze at the end of a distributed run (either contingency or ATC). This has been fixed.
• PV Curve: In the "New Plots" features if you have defined a value to contained in a plot it is automatically stored as part of the result while running the PV tool. However, when choosing to plot a bus dV/dQ value, the value was not being tracked properly with this new feature. This has been fixed.
• Sensitivities: Fixed error in performing AC TLR sensitivities which was caused by a bug introduced in the speed enhancement from July 23, 2010

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September 2, 2010

New Features

• 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: Fixed an error that could occur when running an iterated ATC simulation that involved conditional contingency elements.
• 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.
• 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.
• QV Curve Tool: Modified qvExtraMonitoring file so that the results can be easily identified by the contingency and bus which created the results.
• 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.

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September 10, 2010

New Features

• Available Transfer Capability: Modified internal numerical routines to make them faster.
• Sensitivity Analysis: Modified internal numerical routines to make solutions faster.

Bug Fixes

• Integrated Topology Processing: Fixed a potential issue with restoring states when using consolidation related to a generator's regulated bus number.
• Oneline Diagram: Fixed a oneline "flicker" that could occur when using the line navigation arrows.
• Oneline Diagram: 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.

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September 13, 2010

New Features

• None.

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: 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.

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September 14, 2010

New Features

• None.

Bug Fixes

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

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September 21, 2010

New Features

• Auxiliary Files: Added support for general script commands in the AXD file format to manipulate oneline diagram objects. The following commands can be used: ExitProgram, LoadScript, LoadData, SelectAll, UnSelectAll, SaveData, SaveDataWithExtra, CreateData, DeleteFile, RenameFile, CopyFile, SetCurrentDirectory, and SaveObjectFields.
• Auxiliary Files: The field "Selected" can now be used with oneline display objects. This can be used in the script section for AXD files.
• Available Transfer Capability: Continuing to improve speed of the ATC calculation.
• PV Curve Tool: PV Curve Tool state archiving is now available when using Integrated Topology Processing.
• Transient Stability: Modified the internal storage of the list of Transient Contingencies so that they are sorted. When creating a large number of them (1000s) this is required to improve the speed of reading/writing information from auxiliary files.
• Transient Stability: Added full support for the WT2T, WT2P, and WT2G wind turbine models.
• Transient Stability: Added better reporting of loads that don't initialize.

Bug Fixes

• File Formats: Fixed an error introduced in the last patch which caused problems when loading old PWB files and when loading in PTI RAW files. The load would abort while reading the switched shunt records.
• Power Flow Solution: Improved the performance of the angle smoothing routine when used to close in low impedance branches adjacent to a large number of other low impedance branches (such as in a full topology model).
• Transient Stability: Fixed an error with reading the WT3E model from a DYD file.
• Transient Stability: Improved the accuracy of the initialization of the slip for induction motor load models (such as CIM5, CIM6, MOTORW). This helps ensure that everything initialize to exactly zero derivatives. Previously they were very close. Now they are nearly exactly at zero derivative.
• Transient Stability: Fixed an error in the initialization of the ST6B (also known as ESST6B) exciter when the Km <> 0.

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September 22, 2010

New Features

• Case Information Displays: When choosing "Send to Excel", Simulator will now programatically set Excel to NOT "treat consecutive limiters as one". It also ensures that some "Other" character is not being used as a delimiter so that only TAB characters are used.
• Power Flow Solution: After treating Discrete Switched shunts as continuous shunts in the inner power flow loop, Simulator sets nominal Mvar output to one of the discrete options available. Previously it was biased to set higher Mvar values such that anything at least 5% of the way toward a higher block would switch to the higher block. This has been changed to no longer bias the switching and instead just round to the nearest block.
• Transient Stability: Improving error messeges when the stability simulation aborts.

Bug Fixes

• Transient Stability: Fixed initialization of the EXWTGE exciter if Kiv = 0.
• Transient Stability: Decreased tolerances for initialization of the WNDTGE pitch angle/wind speed to reduce initial mismatches.
• Transient Stability: Increased tolerance for what is considered "zero" when initializing the HYGOV, HYGOV4, HYG3, and WEHGOV hydro governor models. These can be problematic for a generator operating at 0.0 MW output because the equation H = sqr(Q/Qss) becomes ill-defined if Q = 0 and Qss = 0 as occurs in initialization of a generator operating at 0.0 MW output.

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September 27, 2010

New Features

• Auxiliary Files, Case Information Display: Modified the editing of data in a case information display (or through an AUX file) so that the string "&ModelExpressionName:8:4" can be entered. A string which starts with the character & will be treated as though the value of the named model expression is being entered in the field. The format of the string will be determine by the last two integer values representing the total number of digits and decimal places.
• Available Transfer Capability: More modifications for speed of the ATC tool. The overall speed increase from the initial release of Simulator 15 is now between 2 and 6 times for the iterated solution methods and between 4 and 10 times for the Single Linear Step solution methods.

Bug Fixes

• Power Flow Solution: Fixed access violation that could occur when an AC bus terminal of a multi-terminal DC line was outaged.
• Transient Stability: Fixed error in determining whether islands have been created related. If a branch was only open at one end it still can create an island and this was not properly accounted for.

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September 28, 2010

New Features

• Fault Analysis: Added total fault impedance field to TBus, to store the thevenin R and X needed to calculate the total fault X/R ratio.
• Power Flow Solution: Modified slightly when generator limits are checked. Previously they would be checked "immediately" (i.e. inside the inner power flow loop) if the mismatch fell below 0.02 per unit (2 MW or 2 Mvar normally). This could lead to some inconsistent results if in one situation the mismatch when from 2.001 to near zero, and in another it went from 1.999 to near zero. Simulator will now only check generator limits inside the inner power flow loop if the user chooses the "check immediately" solution option.
• Power Flow Solution: Switched back to old way (before September 22) of handling discrete shunts as continuous.
• User Interface Dialogs: On the run mode dialogs for Branches, Generators, Loads and Switched Shunts, add indications of the Energized status of the device.

Bug Fixes

• Available Transfer Capability: Modified some of the tolerances used when ramping the ATC transfer using injection groups when the injection group generators are hitting limits. This fixes a problem where manually increasing the transfer caused the transfer to exceed the desired amount.
• Case Information Displays: When choosing to rename an advanced filter on the Filter Dialog, if the filter was referred to by another advanced filter the link would not be maintained after naming. This has been fixed.
• Transient Stability: Further modifications to the HYGOV, HYGOV4, HYG3, and WEHGOV hydro governor models to avoid problematic 0/0 situation when initializing a generator operating at 0.0 MW output.

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October 1, 2010

New Features

• Transient Stability Tool: Added more validation checks to ensure that only appropriate groupings of wind models are used such as GEWTG/EWTGFC/WNDTGE, GEWTG/EXWTGE/WNDTGE, and GENWRI/EXWTG1/WNDTRB. This help prevent input errors such as using the full converter electrical model (EWTGFC) with a machine model configured as a DFAG (fcflg = 0).

Bug Fixes

• Available Transfer Capability: When using the (IL) the Full CTG Solution method AND while using multiple ATC Scenarios, a bug was was introduced by recent speed enhancements. This has been fixed.
• PV Curve Tool: When tracking a Voltage to Q injection, Voltage to Power Transfer, or PTDF sensitivities in the PV Curve tool it was possible that the calculations were being performed on an invalid Jacobian matrix resulting in incorrect tracking results. This has been fixed.
• Transient Stability: Fixed some GUI interaction issues with the transient stability dialog related to the Manual Control the the run.

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October 5, 2010

New Features

• Case Information Displays: The Transformer Configuration Field is now enterable and toggleable on a case information display.
• File Formats: When loading in EPC files and the latitude and longitude values are both zero, both entries will be ignored as invalid.
• PV Curve Tool: Nominal Shift field is now included in the PV output file. Previously, only the Export and Import fields were included sometimes making it difficult to match up results between a scenario and the base case.
• SimAuto: Labels now supported in SimAuto functions ChangeParametersSingleElement, GetParametersSingleElement, and GetParametersMultipleElement.

Bug Fixes

• Oneline Diagrams: Fixed bug that would not allow custom fields to be correctly assigned with default drawing values for zones.
• Oneline Diagrams: Fixed bug that would not allow any fields to be correctly assigned with default drawing values to multi-section lines.
• Transient Stability: The fields ROpen and RClose with the GGOV governors were not being used. This has been fixed.
• Transient Stability: Modified the transient contingency elements for branches for "Open From End" to "Open To End" to instead be "Open Near End" and "Open Far End" to be consistent with defining the contingency.
• Transient Stability: Added additional Sub-interval integration support in situations where the IEEEST has A1 or A3 values which are too small resulting in numeric stability trouble.
• User Interface Dialogs: Fixed bug that could cause the Model Conditions dialog to not be properly configured when opening the dialog for a particular Model Condition.

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October 15, 2010

New Features

• Case Information Displays: Modified the custom expression parser to allow a floating point to be specified as ".05" or "0.05". Previously the ".05" would cause the parser to fail.
• Case Information Displays: Modified case information displays show that when showing a value such as -0.01 which is truncate to fewer decimal places, the resulting string will still include the negative sign and show "-0.0" for example instead of "0.0".
• Transient Stability: For plots, add the ability to specify special strings such as "@CTGName" which will automatically determine an appropriate string to place in the Plot Title Block Memos, Axis Title captions, Chart Title, or Chart Footer. @CTGNAME will display the appropriate contingency name; @CASENAME will show the name of the case presently open; @BUILDDATE will show the Simulator patch build date; @DATETIME will show the present date and time; @DATE will show the present date; @TIME will show the present time.

Bug Fixes

• File Formats: Write out the Voltage Checking Limit Max and Voltage Checking Limit Min values to EPC files with the same values that were read in. It is OK for them to be zero. We had been adjusting the zero values to values based on the limit monitoring limits.
• File Formats: When using a script to open a case file with a particular version such as "PTI30", Simulator was always using the feature to automatically determine the file format version and was treating the version as "PTI" instead. This has been fixed so that a specific file type may be specified.
• File Formats: The routine to automatically determine the file version of a PTI RAW file would fail and cause an "invalid integer error" if a section was terminated by "0" or '0' instead of just the character 0. This has been modified to accomodate the quotes if they are there.
• File Formats: when writing out FACTS records to Version 30 we were writing a string "name" instead of the integer NUM for the first record. Similarly for Version 31 and 32 we were writing the number instead of the name. This has been fixed.
• Transient Stability: Modified the WEHGOV, HYGOV, HYGOV4, and HYG3 governors so that the turbine flow (q) can not become negative.
• Transient Stability: Fixed bug in which state Id/Iq curents were not getting updated correctly for GenSal model when using subintervals. This bug would show up when the fault is close to the generator.
• Transient Stability: Fixed error in Type 4 wind turbines which require ignoring Xpp.

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October 28, 2010

New Features

• Transient Stability: Added validation check for the ESAC8B model to ensure that both Kir=0 and Kpr=0 is not allowed. The auto-correction will change Kpr to 40 if both are zero.
• Transient Stability: When showing plots in the transient stability dialog Simulator now remembers the size and location of the plot window if you change it. When showing a plot on subsequent stability runs during that session of Simulator the size and location will be remembered.
• Transient Stability: Added validation check for ropen and rup to be positive numbers and rclose and rdown to be negative numbers.
• Transient Stability: Added more error checking with IEEEST stabilizer model when A2/A4 values are small.
• Transient Stability: Added use of 8 subintervals of integration for the EXAC1 model if Ka/Ta is larger than 10,000
• Transient Stability: Fixed small time constant issue with ESAC8BGE model
• Transient Stability: Added read/write support for the HYGOVR model (implementation in dynamic simulation is not completed yet)

Bug Fixes

• Auxiliary File Format: Fixed error in using the SaveCase() command from a script file. Error was introduced in the patch on October 15.
• Contingency Analysis: Fixed errors that could occur when using Free-Floating Windows mode and opening or closing the contingency analysis dialog.
• Fault Analysis: When choosing to write out an AUX file describing all the fault analysis data, the transformer grounding configuration were not being written. A DATA section is now written with this information.
• SimAuto: Fixed error in using the SaveCase command. Error was introduced in the patch on October 15.
• Transient Stability: Fixed error in the handling of circuit parameters for the WT2G model.
• Transient Stability: Fixed a bug when using the EXWTGE exciter model for some values of fVarFlg.

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November 17, 2010

New Features

• Auxiliary File Formats: Added a new file type to the SaveData() script command called "CSVColHeader". When using this file type, the file will be written with the first row showing column headers you would see in a case information display. The file type "CSV" will always show variable names.
• Auxiliary File Formats: Added a support for the new file type "CSVColHeader" to the SaveDataWithExtra() script command also.
• Auxiliary File Formats: Added the script command SendToExcel(ObjectType, [FieldList], Filter, UseColumnHeaders, "WorkBookName", "WorkSheetName") to mimic the behavior of Send to Excel option within a case information display. The first three parameters behave the same as for many other scripts. The UseColumnHeaders parameter should be passed as a YES to signify that the first row shows Column Header or NO to signify that variable names be used. The last two parameters specify the WorkBook Name and the WorkSheet and are optional parameters. If they are blank then a new workbook or worksheet will be created. If a value is specified it will overwrite the existing data in the workbook or worksheet.
• Available Transfer Capability: Added a new option to linearize the calculation of contingency makeup power. This will precalculate the impact of makeup power on line flows at the start of the analysis and then the total effect of makeup power will be determined by multiplying the effect on a line by the Total amount of Makeup power needed. This calculation will be slightly faster than previous calculation of makeup power, but it will not take into account the fact larger amounts of makeup power may cause particular generators to hit min or max limits.
• Case Information Display: In a Custom String Expression, when using the Str(Value, Digits, Decimals) function, if the Decimals parameter is specified as negative, then it will truncate all trailing zeros beyond the decimal.
• File Formats: When appending using the RAW file format, we now populate a field to say whether an object is new or modified while reading.
• Time Step Simulation: Added the storage of the Custom Inputs to the TSB file format.
• Time Step Simulation: Added the storage of the Custom Results for Loads to the TSB file format.
• Transient Stability: Added support for the HYGOVR governor.
• Transient Stability: Added showing the bus frequency on the Transient Load Dialog.
• Transient Stability: Added ability to specify whether to use the Runga-Kutta Order 2 (RK2) or Eulers method for the integration time step.
• User Interface Dialogs: Added checks to prevent a dialog from becoming hidden behind the Windows Taskbar.

Bug Fixes

• Case Information: Fixed the showing of the field names, column headers, and field descriptions of Custom Strings, Integers, Floats, and Expressions for case information displays showing a specific type branche record (Transmission Line, Transformer, Breaker, etc...). Previous the values would appear correctly, but the user-specified field or column names would not appear properly.
• Contingency Analysis: When using the contingency action to open a three-winding transformer, only the primary winding was being opened. This has been fixed.
• Distributed Computation: When using distributed contingency analysis, the existing results were not properly cleared before running the analysis, and thus the results were the concatenantion of previous results with the new results. This has been fixed.
• File Formats: When appending using the RAW file format, three-winding transformers were always being created instead of modifying an existing record.
• Sensitivities: Modified default column on the Flows and Voltages dialog so that the list of LTCs includes the Voltage to Tap Sensitivity

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November 23, 2010

New Features

• Auxiliary Files: Added new script command to find branches that create islands.
• Transient Stability: Added a new option to specify the type of saturation function to use for an exciter model. Choices are Quadratic, Scaled Quadratic, or Exponential.
• Transient Stability: When loading a PSLF DYD file, modified to specify that the Quadratic exciter saturation function be used.
• Transient Stability: When loading a PSS/E DYR file, modified to specify that the Scaled Quadratic exciter saturation function be used.
• Transient Stability: When loading a IPF SWI file, modified to specify that the Exponential exciter saturation function be used.
• Transient Stability: Modified the captions of plots to use identifiers as specified by the "Identify Buses in Events and Results by" option.

Bug Fixes

• File Formats: When loading the HDB Export CSV file format, the custom strings for ZBR records were not saving the Line ID.
• Integrated Topology Processing: After saving a case as a consolidated case, access violations could result if Calculated Fields existed. The case was saved correctly, but the the process of saving could corrupt the existing case in memory. This has been fixed.
• Power Flow Solution: When using the feature on the MW Transactions table to choose to "Clear Transactions and Auto-Insert Tieline Transactions", if one of the multiterminal DC Converters was acting as a tie-line, then the resulting transaction totals were incorrect. This has been fixed.
• Transient Stability: Fixed a bug when writing out a GE DYD file which contained a PIDGOV governor. If one of these governors existed, then writing out the DYD file would cause the program to halt.

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December 1, 2010

New Features

• Auxiliary File Format: Added new script command DetermineBranchesThatCreateIslands(BranchesToProcess, StoreBuses, "FileName", SetSelectedOnLines);
  This script action determines the branches whose outage results in island formation. There are options to specify the branches to process, whether or not to store the islanded buses to the output file, the output filename, and an option to set the selected flag on branches that create islands. Note that setting the Selected field will overwrite the Selected fields.
  BranchesToProcess: The branches to consider while determining outages that create islands. ALL: consider all branches SELECTED: consider branches with a selected flag set to true AREAZONE: consider branches meeting AREA/ZONE filters "Filtername": consider branches that meet the filter given in filtername. Note that a valid branch fliter with the name specified by filtername must exist. StoreBuses: YES or NO field that specifies whether the buses in the island are stored in the output file. The output file is an aux file. The branches that create islands are stored in a single data section. When the buses are also stored, the buses are in a data section immediately following the branch data section, so there is a pairing between the outaged line(s) and the islanded buses.
  "Filename" : the name of the file to which the output will be stored. If the filename is empty ("") or simply blank, then the results will not be stored in a file. This will only be useful if the results are stored in the Selected field for the branches instead.
  SetSelectedOnLines: YES or NO field that determines if the SELECTED field will be set to YES for branches that create islands.
• File Formats: When appending an EPC file with a scheduled voltage for a bus, the voltage setpoints for switched shunts and generators that are regulating this bus are now properly updated.

Bug Fixes

• Oneline Diagrams: When inserting a new transmission line on a oneline, an access violation occurred. This has been fixed. The error was introduced in the 11/23 patch.
• Transient Stability: Fixed minor bug in the REXSYS exciter

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December 10, 2010

New Features

• Auxiliary Files: Modified the Move() script command to permit you to move a MULTISECTIONLINE. The format is the same as for moving a regular branch except that the object name should be MULTISECTIONLINE.
• Oneline: When opening a oneline diagram using the AXD format, if no Saved View named THIS_VIEW_IS_APPLIED_TO_THE_CURRENT_DISPLAY is specified, then a Show Full will automatically occur for the oneline.
• Power Flow Solution: Modified the algorithm which automatically chooses a slack bus when a new island is created. Previously, if possible, it would always choose a bus which had generation that regulated its own terminal bus. Now it is biased to do this, but if another bus with generation that does not regulate its terminal bus is available and this other bus has a maximum MW output that is 5 times higher, it will be chosen.
• Transient Stability: When modeling a GENCLS model with H=0 and D=0 it is now treated as an infinite bus.
• Transient Stability: Modified two bus equivalent saved from the SMIB portion of the dialog, we now save a GENCLS model on the slack bus saved to represent an infinite bus.
• Transient Stability: Added the ability to read a "DYR file with options". When choosing this, you may specify a MCRE *.rwm file to split up generators, a MTRLD *.dat file to split up motors, a GNET *.idv file to disable generator models, and a BASEGEN *.dat to specify the Governor Response Limits flag for generators.
• Transient Stability: When writing out a DYR file, we now automatically write out a GNET *.idv and a BASEGEN *.dat file. The filename and patch used will be the same as for the DYR file, except "_GNET" and "_BASEGEN" are appended to the filenames.

Bug Fixes

• Auxiliary Files: Fixed an error in parsing the parameters of the OpenCase() script command choosing to open a PTI or GE file with options. The options specified would be ignored if there was a space between the comma and the bracket "[" which started the specification of the options.
• Case Information Displays: In versions of Simulator without the PVQV add-on, the ability to Toggle the Injection Group filed Scale? was not working. This has been fixed.
• Contingency Analysis: Fixed error on What Actually Occurred? descriptions when using a SetTo or ChangeBy action for a Generator, Phase Shifter, or DC Line setpoint. The Contingency was always processed correctly, but the What Actually Occurred? string was incorrect.
• Distributed Computation: Fix for distributed computation if machines finished initializing *after* computation had already completed, an access violation would occur.
• File Formats: When appending an EPC file, fixed a problem with creating a multi-section line where the existing line was not a multi-section line.
• Oneline Diagrams: Fixed error on the Find Oneline Objects dialog when tyring to define a filter for the list of objects.
• User Interface Dialogs: When creating an equivalent, if any terminal of a three-winding transformer was chosen to be in the External System, then all the terminal buses and the star bus would be flagged as in the external system. This has been modified so that only the star bus is automatically flagged as in the external system.
• User Interface Dialogs: Modified the processing of what is considered a radial branch when choose to Remove Radial Systems on the Equivalencing Dialog. Previously the entire three-winding transformer would be equivalenced even if only the tertiary winding ended up begin connected radially.
• User Interface Dialogs: On the Calculated Field Dialog an access violation occurred when choose to set the condition the Same as a Filter. This has been fixed.

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December 28, 2010

New Features

• Auxiliary Files: Added a new script command called "StopAuxFile". This command will effectively treat the remainder of the file after this command as a big comment. This includes any script commands inside the present SCRIPT block, as well as all remaining SCRIPT or DATA blocks.
• File Formats: When appending to an existing case using an EPC file or a RAW file, any new branches that are created are now flagged as having just been added. This flag is then used as part of the pre-processing feature in the power flow solution to automatically estimate appropriate voltage magnitudes and angles for any existing or new buses that become newly energized.
• Power Flow Solution: When pre-processing the voltage profile of a solution before solving, Simulator will now look at groupings of buses connected by very low impedances lines. If a bus in a grouping of energized buses has a zero voltage while other buses in the group do not, the zero voltage will be changed to the first non-zero voltage found in the grouping. This provides a much more reliable solution.
• PV and QV Curves: Optimized the solution speed of the PV and QV curves tools. The QV curve especially should run much more quickly, especially on cases smaller than a few thousand buses.
• Transient Stability: Added an appropriate error message when the transient stability aborts due to a failed network equation solution.
• Transient Stability: Added read/write support for the LD1PAC load model, which is used to represent small air conditioner load.
• Transient Stability: Added full support to TGOV5 and set the defaults for boiler-follow control.
• Transient Stability: Added full support for the CSTATT static condensor model

Bug Fixes

• Auxiliary Files: Allow blank entries for custom expression variables. This is necessary so that when loading an auxiliary file that contains an existing custom expression the custom expression will end up being defined correctly if variables that previously existed should no longer exist.
• Auxiliary Files: Fixed editing of the switched shunt records for any of the special "EPC File" fields.
• Integrated Topology Processing: Fixed an error with defaulting that Allow Consolidation field of all branched back to YES whenever a DATA section for the BRANCH object type was read from an AUX file
• Transient Stability: When loading a PTI DYR file which contains GENCLS models, the Ra and Xdp values were not being automatically set to internal impedance values. This has been fixed.
• Transient Stability: Modified to prevent the network equation convergence tolerance from being set to a value smaller than 1E-5.
• Transient Stability: Fixed bug with CIM models in which they were not being autocorrected if Xl > Xpp
• Transient Stability: Removed limit check for generator impedance values since these values can differ substantially when MVA base for generator is set to the power flow base, as is common in older cases.

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January 5, 2011

New Features

• File Formats: Modified how appending an existing three-winding transformer is handled if a new three-winding transformer is entered which uses a bus number which is already used as a star bus by another transformer. This is not allowed and a new bus number will automatically be chosen.
• General: Modified how Simulator handles setting its Windows Operating System Priority so that the user can change this. The only exception is that while animating, Simulator alwasy sets its Priority to Low to ensure that the animation does not interfere with other programs.
• Transient Stability: Added a new transient contingency event for "OPEN BUS" which opens all AC lines connected to a bus.
• Transient Stability: Modified the transient limit monitors to allow an option to "Trip (Open) Device" if a monitoring violation occurs. This works for Buses, AC Lines, Generators, Loads, and DC Lines.
• Transient Stability: When choosing to load a DYR file using options, we now auto-populate the various GNET, MTRLD, BASEGEN, and MCRE file if a file with appropriate name exists.

Bug Fixes

• User Interface Dialogs: Fixed various bugs with manually creating a multi-terminal DC line from scratch.

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January 14, 2011

New Features

• Transient Stability: Added the ability to automatically save plot images during a transient stability run. The images will be saved in the same directory as the defined hard-drive storage directory.

Bug Fixes

• Auxiliary Files: Fixed reading of auxiliary format export descriptions to clear existing Object Types when reading in replacement export descriptions.
• File Formats: Fixed an out of bounds error that occurred when reading version 32 RAW files generated by Model on Demand that didn't contain some options on the title line that would normally be present. In the absence of these options, Simulator will generate defaults instead.
• General: In certain instances a load could be double counted in the list of owners if its owner is the same as its terminal bus' owner.
• Integrated Topology Processing: In some instances, the flows on consolidated branches weren't being calculated after deconsolidation. This has been fixed.
• Oneline Diagrams: Fixed line-based display objects so that all vertices snap to the grid.
• Transient Stability: When reading a DYD file and choosing to split generators represented by GENCC machines, a bug was introduced in the December 10, 2010 patch which caused both generators to have the same Generator ID. This has been fixed.
• Transient Stability: Fixed Show Dialog... right-click menu option in the Validation listing to properly show the Generator dialog.

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January 25, 2011

New Features

• None.

Bug Fixes

• Auxiliary File: When using the CaseDescriptionSet() script command to specify the case description, Simulator then sets the case description but includes the double quotes around the entire description. The double quotes are now removed.
• Auxiliary File: Fixed bug with CTGWriteResultsAndOptions script that would not read the options correctly if there was an extra space before the bracket enclosing the options.
• File Formats: Fixed reading of the QTable from an EPC file.
• File Formats: When writing out area/zone information for branches to the EPC file, if the EPC extra data is not available, we now write the area/zone to which Simulator will assign the line losses (as determined by the metered end of the branch)
• File Formats: When loading the Areva hdbexport CSV file while Windows Localization settings were set to use a comma as the decimal separator, all values were read incorrectly. This has been fixed.
• Optimal Power Flow: Fixed error when solving a DC OPF in that we were not resolving the power flow after modifying a MW transaction control variable. The DC Power flow is needed here even in the DC OPF because we need to redispatch the generation in the non-OPF area.
• Power Flow Solution: When using the DC approximation, the flow on DC transmission lines was not being properly updated if the user changed the MW or Amp setpoint. This has been fixed.
• Time Step Simulation: Fixed errors with applying schedule subscriptions when time points were left out of the schedule.
• Transient Stability: Fixed error with writing out the WT4E1 model to a DYR file. The last 3 parameters were omitted and 3 integer parameters were written out as floating point numbers.
• Transient Stability: Fixed error when switching between different dynamic models on the generator dialog. The number of decimal points shown for various values on the dialog were not always being updated appropriately.
• User Interface Dialog: When using the merge buses feature, the newly merged bus must have its angle set based on the old buses to prevent a badly conditioned initial voltage estimate.

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January 28, 2011

New Features

• Case Information Displays: Modified the right-click menu for case information displays so that if no substations exist, then the Sub View is not enabled.
• File Formats: When loading a RAW or EPC file, the participation factor for generators at a slack bus were set to zero. This has been changes so slack generators are set the same as other generator (MBase/SBase)
• Integrated Topology Processing: Added a new field for object types Branch, Gen, Load, Shunt, and DCLine which shows the "Derived Status". For full topology power system models, this field will show whether the breakers adjacent to a device are OPEN or CLOSED. If the device is energized, the field will always show CLOSED. If the device's actual Status is OPEN, the field will alway show OPEN. If the device's actual status is CLOSED, but the device is not energized, the software will determine if any adjacent Breaker objects are CLOSED in which case the derived status will show CLOSED - otherwise it will show OPEN.
• Transient Stability: Added the ability to load the MCRE, MTRLD, GNET, and BASEGEN files each separately if desired.
• Transient Stability: Added new script commands for Transient Stability Tool which are all available in the PowerFlow submode.
• Transient Stability: TSSolveAll - Solves all specified transient contingencies.
• Transient Stability: TSSolve("ContingencyName", [StartTime, StopTime, StepSize]) - Solves only the specified transient contingency. StartTime, StopTime, and Stepsize are specified in seconds.
• Transient Stability: TSWriteOptions("FileName", [opt1, opt2, ... opt5], KeyField) - Save the transient stability option settings to an auxiliary file specified by FileName. Opt1 through Opt5 should be set to YES or NO according to the specific option categories to save. These parameters are optional and the default is YES for any parameter not specified. opt1 - Save Dynamic Models; opt2 - Save Stability Options; opt3 - Save Stability Events; opt4 - Save Results Settings; opt5 - Save Plot Definitions; KeyField – Optional parameter. Primary, Secondary, or Label. If not specified set to Primary by default.
• Transient Stability: TSCalculateSMIBEigenValues - Calculate single machine infinite bus eigenvalues. Initialization to the start time is always done before calculating eigenvalues.
• Transient Stability: TSSaveTwoBusEquivalent("PWBFileName",[BUS busnum]) - Save the two bus equivalent model of a specified bus to a PWB file. Initialization to the start time is always done before saving the two bus equivalent. “PWBFileName” – name of the PWB file to which to save. Bus can be specified by number [BUS busnum], name/nominal kV combination [BUS "busname_nominalKV"], or label [BUS "buslabel"]
• Transient Stability: TSLoadGE("FileName",GENCCYN) - Loads transient stability data stored in the GE DYD format. “FileName” – name of the DYD file to load. GENCCYN - YES or NO. Set to YES to split combined cycle units. Set to NO to leave them alone.
• Transient Stability: TSLoadBPA("FileName") - Loads transient stability data stored in the BPA format. “FIleName” – name of the BPA file to load
• Transient Stability: TSLoadPTI("FileName", "MCREfilename", "MTRLOfilename", "GNETfilename", "BASEGENfilename") - Loads transient stability data in the PTI format. “FileName” – name of the DYR file to load. This is NOT an optional field. All of the files listed after are optional. If not loading these particular files, specify an empty string, "".

Bug Fixes

• Sensitivities: The Sensitivity value for a branch's Mvar or MVA flow when the branch was connected to a PV bus was not being properly calculated. This has been fixed.
• Transient Stability: Fixed an error when reading the MCRE field with how omitted fields are treated in the MCRE file.

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February 4, 2011

New Features

• Transient Stability: Added error check on the summation of Kx inputs for the TGOV5 and WSIEG1 governor models.
• Transient Stability: For the Transient Limit Monitors, added the ability to filter using area/zone filters.
• Transient Stability: Added ability to record the Interface "Limit %" and the Branch "Limit %" during a stability run.
• Transient Stability: Added right-click option to create a two-bus equivalent to the generator state case information displays.
• Transient Stability: Added routines to initialize new machine models at a generator based on the existing active machine model at the generator.
• Transient Stability: Added auto limit correction for the REXSYS Vimax limit
• User Interface Dialogs: Added the losses to the branch Run Mode dialog. Also changed layout of flows.

Bug Fixes

• Transient Stability: Fixed error with assigning an owner when reading the MTRLD helper file in splitting up loads when reading a DYR file with options.
• Transient Stability: When showing the Bus Voltage maximum decrease or increase, the values were backwards. This has been fixed.
• Transient Stability: Fixed errors in the modeling of faulted branches which are only closed at one end.
• Transient Stability: Fixed error in handling of scaling of low pressure values in the WSIEG1 model

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February 15, 2011

New Features

• Transient Stability: When inserting a new machine model at a generator, add the ability to initialize the new generator model with parameters taken from an existing machine model of a different type.
• Transient Stability: Added newly named model for ESDC4B, ESST6B, ESST7B which are identical to the DC4B, ST6B, and ST7B models. Done to make names consistent with DYD file naming.
• Time Step Simulation: Modified the Time Step processing when using the SCOPF algorithm at each time step so that less messaging is sent to the Time Step dialog regarding the progress of the sCOPF solution. All the messaging to status edit boxes on the Time Step dialog was greatly slowing down the solution process.
• Time Step Simulation: When using the DC-Approximation, modified the SCOPF dialog so that less messaging is sent to the SCOPF dialog regarding the progress of the sCOPF solution. All the messaging to status edit boxes on dialog was greatly slowing down the solution process.

Bug Fixes

• Case Information Displays: On the Area or Zone Tie-lines case information display, a tie-line representing a DC line was not properly showing the Far Bus' number and other information. This has been fixed.
• Optimal Power Flow: Modified how OPF solution involving multiple islands with dispatchable MW Transaction and DC Lines is coordinated. The DC lines and MW Transactions are now coordinated to ensure that the inter-island DC lines flows are appropriately managed.
• Optimal Power Flow: When using a dispatchable MW Transaction between two areas on OPF with the MW transaction price determined by the OPF, the post-OPF book-keeping for showing an Area's total cost including transaction costs was not handled appropriately. This has been fixed so that the Import and Export area have an appropriate exchange of money for the transaction exchanged.
• Power Flow Solution: Fixed potential floating point error when a failure occurs in the robust solution process.
• Power Flow Solution: When loading a power system model, additional code was added to ensure that generators regulated the same bus have the same setpoint.
• Time Step Simulation: Modified the Schedule Subscription dialog to sort the object id list, field list, and schedule list alphabeticially.
• Time Step Simulation: Fixed error when showing the Schedule Subscription dialog when specifying a multiplier with a negative sign.
• Time Step Simulation: Added ability to use an advanced filter when showing the list of Schedules or the list of Schedule Subscriptions
• Transient Stability: When loading in an AUX file containing plot definitions, the Plot Designer was updated to list this new definitions until the Transient Stability dialog was closed and reopened. This is now properly updated immediately.
• Transient Stability: Fixed bad behavior of the Transient Stability Plot Designer when running in Free-Floating Windows mode.
• User Interface Dialog: When using the user-interface to apply an advanced filter to a oneline display object (such as on the Select By Critera or Export KML file dialogs), an access violation could occur. This has been fixed.

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February 16, 2011

New Features

• Transient Stability: When storing a PWB file, the presently active contingency is now flagged so that when we re-open the PWB the PWB file this transient contingency is initialized as the active one.

Bug Fixes

• Transient Stability: Handled potential problem with very small Ta values in the EXBAS exciters when there is feedback to prevent numerical instability.
• Transient Stability: Fixed initial limit violation handling of Vfemax in the EX2000 exciter.
• Transient Stability: Fixed access violation that could occur when using the CLOD load model.

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February 22, 2011

New Features

• Sensitivities: Added interface fields for showing the LODF and the Post-CTG MW flow (after Line outage) values similar to those presently available for a branch.
• Transient Stability: Added full integration support for the ST7B and ESST7B exciters.
• Auxiliary Files: New script command called.
  AutoInsertBorders;
  which uses the AutoInsertBordersOptions object to set the options.
• Auxiliary Files: New script command called.
  AutoInsertBuses(Location Source,Map Projection, AutoInsertBranches, InsertIfNotAlreadyShown, “FileName”, FileCoordinates);
  Location Source – "Bus","Substation", "File"
  Map Projection – "Simple Conic", "Mercator", "x,y"
  AutoInsertBranches – YES or NO if transmission lines should be inserted when finished
  InsertOnlyIfNotAlreadyShown – YES if only buses that are not already shown should be inserted, NO if all buses should be inserted
  "FileName" – optional if Location Source is File. File containing the bus locations.
  File Coordinates – optional if Location Source is File. "x,y" or "lon,lat"
• Auxiliary Files: New script command called.
  AutoInsertLoads(MinkV, InsertTextFields, InsertEquivObjects);
  minKV = Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to insert Text Fields | Default Value = Yes
  InsertEquivObjects = optional field regarding whether to insert Equivalenced Objects | Default Value = Yes
• Auxiliary Files: New script command called.
  AutoInsertGens(MinkV,InsertTextFields);
  minKV = Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to insert Text Fields | Default Value = Yes
• Auxiliary Files: New script command called.
  AutoInsertSwitchedShunts(MinkV, InsertTextFields);
  minKV = Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to insert Text Fields | Default Value = Yes
• Auxiliary Files: New script command called.
  AutoInsertLines(MinkV, InsertTextFields, InsertEquivObjects, InsertZBRPieCharts, InsertMSLines, ZBRImpedance, NoStubsZBRs, SingleCBZBRs);
  minKV = optional field for Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to Insert Text Fields | Default Value = Yes
  InsertEquivObject = optional field regarding whether to Insert Equivalenced Objects | Default Value = Yes
  InsertZBRPieCharts = optional field regarding whether to Insert pie chasrt for lines with no limit and bus ties | Default Value = No
  InsertMSLines = optional field regarding whether to Insert Multi Section Lines | Default Value = Yes
  ZBRImpedance = optional field regarding whether to Maximum P.U. Impedance for Bus Ties | Default Value = 0.0001
  NoStubsZBRs = optional field regarding whether to Do not Insert Stubs for bus ties | Default Value = Yes
  SingleCBZBRs = optional field regarding whether to Only Insert a single circuit breaker | Default Value = Yes
• Auxiliary Files: New script command called.
  AutoInsertLineFlowObjects(MinkV, InsertOnlyIfNotAlreadyShown, LineLocation, Size, FieldDigits, FieldDecimals, TextPosition, ShowMW, ShowMvar, ShowMVA, ShowUnits, ShowComplex);
  minKV Minimum KV level | Default Value = 0
  InsertOnlyIfNotAlreadyShown = optional field regarding whether to insert if Existing line flow object exist, do not auto insert new ones
  LineLocation = optional field regarding whether to Where to insert flow objects : 0 - Middle, 1 - 10%/90%, 2 - After Stubs
  Size = optional field for Size | Default Value = 5.0
  Fielddigits = optional field for Total Field in Digits | Default Value = 6
  FieldDecimals = optional field for Digits to right of decimal | Default Value = 2
  Textposition = optional field for Flow Text position above: Yes - above, No – below | Default Value = Yes
  Showmw = optional field for Show MW | Default Value = Yes
  Showmvar = optional field for Show Mvar | Default Value = Yes
  Showmva = optional field for Show MVA | Default Value = Yes
  Showsuffix = optional field for Show Units | Default Value = Yes
  Showcomplex = optional field for Show Complex (MW + jMvar) | Default Value = No
• Auxiliary Files: New script command called.
  AutoInsertSubstations(Location Source,Map Projection, AutoInsertBranches, InsertIfNotAlreadyShown, “FileName”, FileCoordinates);
  Location Source – "Substation", "File"
  Map Projection – "Simple Conic", "Mercator", "x,y"
  AutoInsertBranches – YES or NO if transmission lines should be inserted when finished
  InsertOnlyIfNotAlreadyShown – YES if only substations that are not already shown should be inserted, NO if all substations should be inserted
  "FileName" – optional if Location Source is File. File containing the substation locations.
  File Coordinates – optional if Location Source is File. "x,y" or "lon,lat"
• Auxiliary Files: New script command called.
  AutoInsertLineFlowPieCharts(MinkV, InsertOnlyIfNotAlreadyShown, InsertMSLines, Size);
  minKV Minimum KV level | Default Value = 0
  Size = optional field for Size | Default Value = 5.0
  InsertOnlyIfNotAlreadyShown = optional field for If existing line flow objects exist, do not auto insert new ones | Default Value = Yes
  InsertMSLines = optional field for Insert Multi-Section Line Flow Objects if applicable | Default Value = Yes
• Auxiliary Files: New script command called.
  AutoInsertInterfaces(InsertPieCharts, PieChartSize);
  InsertPieCharts = optional field for Insert pie Charts on Interfaces | Default Value = Yes
  PieChartSize = optional field for Default Size of interface Pie Charts | Default Value = 50.0
  Note: Only creates for interfaces that contain an Area to Area element or a Zone to Zone Element
• Auxiliary Files: New script command called.
  ResetStubLocations(ZBRImpedance,NoStubsZBRs);
  ZBRImpedance = optional field for Max P.U. Impedance for Bus Ties | Default Value = 0.0001
  NoStubsZBRs = optional field for Do not insert stubs for bus ties | Default Value = Yes

Bug Fixes

• Transient Stability: Added proper implementation of the fVltFlg=1 for the WT3E1 wind turbine electrical controls

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February 28, 2011

New Features

• Sensitivities: Previously it was only possible to open one instance of the the LODF dialog at a time. This was because only one LODF result was stored so performing the calculation on one dialog changed the results on other open dialogs even if the chosen branch did not change on the other dialogs. This caused confusion and thus resulted in us restricting to one one LODF dialog. This has now been modified to allow two LODF dialogs to be open simultaneously, but when doing this Simulator forces one dialog to show a "Single LODF" calculation, while the second dialog shows the "LODF Matrix". This is less confusing because the "LODF matrix" results are stored separately and thus can be displayed separately.
• Sensitivities: Same modification done for PTDF dialog by restricting the first dialog to "Single" Directions, while the second dialog shows "Multiple" directions.
• Sensitivities: Same modification done for TLR/GSF dialog by restricting the first dialog to the "Line/XFMR or Interface" device type, while the second dialog shows "Multiple Elements" device type.

Bug Fixes

• Case Information Displays: When on the Area/Zone/Owner Filters dialog, modified the Save As > Auxiliary File option works. Previously it always wrote out the Area/Zone Number, Name and Shown Field. This was a problem because it may cause you to rename your areas or zones unknowingly. It will not prompt asking whether to write out using the Primary (Number) or Secondary (Name) key fields.
• File Formats: Fixed text when reading a GE EPC file for message regarding generators being set to "AVR = NO". Previously the number of generators changed was correct, but the number of affected buses was not.

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March 15, 2011

New Features

• Case Information Displays: Added fields for Owner records showing the Number of Branches by Type (Transformer, Line, SeriesCap, Breaker, Disconnect), and the number of switched shunts.
• Transient Stability: Added support for PSS3B stabilizer

Bug Fixes

• Case Information Displays: Fixed error with using a switched shunt filter on another object type as a "secondary filter".
• File Format: Fixed problem with appending switched shunts to a case using a RAW file. Previously, the modified switched shunt records were flagged as "created" instead of "modified".
• General: Fixed GUI error when closing a branch in a dead island. Simulator was modifying the voltage magnitude to 1.0 even though the island was dead.
• General: When using a remote desktop connection, it was possible for an error "A call to an OS function failed" to occur. This did not cause further trouble, but did require the user to dismiss a dialog.
• Oneline Diagrams: When creating PWFormOptions by reading an AXD file into an existing oneline, the new PWFormOptions object will be initialized with the settings present oneline.
• Power Flow Solution: Fixed error introduced in Feb 15 patch related to the coordination of the voltage setpoint by generators which have the same regulated bus. An error was introduced if you were modifying the regulated bus while at the same time modifying the voltage setpoint. Simulator would modify the other generators that had a common regulated bus even though the generator's regulated bus was just changed. This has been fixed.
• User Interface Dialogs: On the multi-section line dialog, modified the Find dialog which appears when searching for the from bus of a new multi-section line so that is allows sorting by name, number or label.
• Time Step Simulation: Fixed a problem with reading in a TSB from a newer patch release into an older patch release. It wouldn't filter out all of the custom result and custom input fields that don't exist in the older patch release.

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March 24, 2011

New Features

• Case Information Displays: Added fields for injection groups that list Area/Zone/Owner of all of the devices in the injection group. Fields are available for listing either the number or name of the associated Area/Zone/Owner.
• Contingency Analysis: Two different types of fields are now available with contingencies to list the Areas/Zones/Owners associated with the elements of the contingency. Fields exist for listing either the number or name of the associated Areas/Zones/Owners. Fields that are labeled with “recurse” will look inside injection groups, interfaces, and contingency blocks for identifying the associated Areas/Zones/Owners. Fields without “recurse” will not look inside injection groups, interfaces, or contingency blocks.
• Transient Stability: Added exciter models BBSEX1, IVOEX, and EXIVO.
• Transient Stability: Added stabilizer models PSSSH and IVOST.
• Transient Stability: Added full support for HYPID governor model.

Bug Fixes

• Contingency Analysis: A change implemented with the Feb. 15, 2011 patch caused the contingency analysis to run much slower. This has been fixed.
• Power Flow: Fixed remote regulation check done when verifying if a generator is able to remotely regulate its specified bus. If the regulated bus of a generator also has a generator that regulates a different bus, that bus is not allowed to be remotely regulated. Both the generator that is remotely regulating that bus and the generator at that bus will be turned off AVR.
• Optimal Power Flow: Fixed a bug that could result if dispatching transactions in the OPF where the generation in the area not on OPF control would not be adjusted for the change in the transaction. This would only occur when using the DC OPF.
• QV Curve Tool: While in Free-Floating Windows mode the QV dialog could not be opened. This has been fixed.

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March 25, 2011

New Features

• Transient Stability: Added full support for generator relay models LHFRT and LHVRT.

Bug Fixes

• File Formats: When writing out area/zone information for transformers to the EPC file, if the EPC extra data is not available, we now write the area/zone to which Simulator will assign the transformer losses (as determined by the metered end of the branch). This should have been included in the January 25 patch but was missed.

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April 5, 2011

New Features

• Available Transfer Capability: Removed the option Apply PTDF Cutoff for Limiting Elements with Contingencies. It really didn’t make any sense to eliminate limiters that are limiting during a contingency if they are not limiting in the base case.
• Auxiliary Files: Added optional parameter to SaveCase script command for use when saving an EPC file. New format is SaveCase("filename",SaveFileType,[PostCTGAGC, UseAreaZone]); PostCTGAGC by default is set to NO. Set to YES to set the base load flag in the EPC file based on the Post-Contingency Prevent AGC Response setting. If preventing post-contingency AGC, the base load flag is set to 1. If not preventing post-contingency AGC or this option is set to NO, the base load flag is set to 0. UseAreaZone by default is set to NO. Set to YES to limit the entries in the EPC file based on the area/zone/owner filter.
• Bus View and Substation View Onelines: Now storing option settings for displaying MW branch, Mvar branch, and MW interface flows in absolute value in the registry. The values stored in the registry will be used as the defaults for these settings when oneline options don’t exist for the Bus View or Substation View with the power flow case (PWB).
• General: Amps field is now available with loads.
• Time Step Simulation: When using the column plotting option to plot time points, time scale will now be in seconds if no difference between time points is greater than one minute.

Bug Fixes

• Auxiliary Files: Modified to ensure that Area or Zone information is written using secondary key fields if requested. This affects Limit Monitoring Settings, Contingency Area Make-Up Power, and OPF options.
• Contingency Analysis: Fixed problem with linear contingency analysis that could cause incorrect results due to islanded generation or load not being accounted for. This also affects linear ATC analysis.
• File Format: Fixed problem with reading in the limits for ZBRs from an Areva hdbexport CVS file.
• File Format: Fixed a problem when writing to an EPC file so that generator setpoint voltages get reflected correctly in the scheduled voltages of the buses that they are regulating.
• File Format: When writing to RAW and EPC files, account for generators that are on line drop/reactive current compensation by setting them to regulate their own terminal bus to the present voltage at the terminal bus.
• Model Explorer: Fixed random access violations that could occur when using the Model Explorer.
• Power Flow Solution: Additional code was added to ensure that generators regulating the same bus have the same setpoint. This change enhances similar changes made in the Feb. 15, March 15, and March 24 patches.
• Security Constrained OPF: Fixed problem with not being able to run more than one Outer Loop Iteration (contingency loop) during the AC SCOPF. The process would abort because it thought that there were no control changes during the first outer loop iteration.

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April 12, 2011

New Features

• Auxiliary File: Added a new script command called "SetGenPMaxFromReactiveCapabilityCurve(filter);". For generators which use a capability curve, the script will change the Maximum MW output of the generator to be equal to the second-to-last MW point on the capability curve if the last Max Mvar point on the capability curve is smaller than 0.001 Mvar. (Also if the present MW output is higher than this new Max MW value, then Max MW is set to the present MW output). The filter parameter is optional and uses the standard filter options of Selected, AreaZone, or "AdvancedFilterName". If omitted, then all generators are processed.
• Transient Stability: Added support for the coordination of the status of sections of a multi-section line in the transient stability simulation.
• Transient Stability: Added support for interface elements of type "multi-section line" when storing results of interface flows in the transient stability tool. Previously multi-section line elements of an interface were ignored.

Bug Fixes

• Oneline Displays: When saving the Dynamic Formatting descriptions to an auxiliary file, associated advanced filters were saved previously. However, if those advanced filter referred to other advanced filters then the referred to filters were not included. This has been fixed.
• Power Flow Solution: An error in the power flow solution was introduced in the April 5 patch. The errors were related to how generator remote voltage regulation was configured when multiple generator regulated the same bus. The error would not cause an incorrect power flow solution, but would frequently cause no solution to be achieved.
• Auxiliary Files: Modified to ensure that Area or Zone information is written using secondary key fields if requested. This affects Limit Monitoring Settings, Contingency Area Make-Up Power, and OPF options.

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April 20, 2011

New Features

• Transient Stability: Added full support for the WT4E wind turbine "exciter"

Bug Fixes

• Case Information Displays: Fixed error displaying min and max tap on the transformer bases for transformers with a fixed tap on the From bus
• Contingency Analysis: In the contingency solution where the line-drop compensation was used to change a generator to regulate its terminal, if the next contingency involved the closure of a line near a generator whose regulated bus was changed then the angle smoothing routine may cause the power flow solution to be pushed toward an incorrect (low voltage) solution. This has been fixed.
• Time Step Simulation: Fixed some problems with plotting and displaying custom results for Owners, Zones, Loads, Transformers, and Super Areas.

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April 29, 2011

New Features

• Transient Stability: Fully implemented the WT4T model.

Bug Fixes

• File Formats: For three-winding transformers with the tertiary winding omitted, the reading and writing of the internal star bus voltage and angle has been modified to be consistent with the treatment of these buses in the EPC file format.
• File Formats: Fixed bug with writing out the transformer grounding code for sequence data files.
• General: Fixed bug that could occur when changing the area or zone of a generator, load, or switched shunt to be something other than the area or zone of its terminal bus. Zero would be reported for the area or zone instead of the correct area or zone.
• Oneline: Fixed bug that would cause the generator rotor symbol to not be set correctly when it was set upon initial insertion of the generator display object.

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May 5, 2011

New Features

• PV Curve Tool: Added a new YES/NO optional parameter to PVWriteResultsAndOptions("filename", AppendFile). Specifying NO will cause it to overwrite the existing file. Specifying YES will cause it to append to the file. If not specified, then YES is assumed.

Bug Fixes

• PV Curve Tool: Fixed error when loading PV results summary table from aux file on top of existin results (loading in fresh new results worked correctly). If the existing PV Scenario in results was critical, but the aux file contains the same scenario which was NOT critical, the results table would not load correctly.

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May 31, 2011

New Features

• Oneline Diagrams: Store default filetype (number, name_kV linking, label linking, or AXD) to make it easier to open subsequent onelines using the same filetype.
• QV Curves: Attempt to speed up the process of determining how much additional var support is necessary for the power flow solution to converge when a contingency will not solve in the base case. Now look for the solvable point by tracing the QV curve from the present base case voltage up to the maximum voltage instead of tracing from the present base case voltage down to the minimum voltage.
• Script Commands: New script command SetScheduledVoltageForABus([bus identifier], voltage). This command sets the stored scheduled voltage, vsched, for a bus according to how this is defined in the EPC format. This value is not used by Simulator but is stored for purposes of writing out to an EPC file. The setpoint voltages for generators and switched shunts regulating the specified bus are also set to the new voltage. The regulation range for switched shunts are modified for the new setpoint voltage according to how this is defined in the EPC format: vband = (VHigh-Vlow)/2 with newVHigh = voltage + vband and newVLow = voltage - vband.

Bug Fixes

• Available Transfer Capability: When running iterated ATC methods, the option to dynamically add slack buses as topology changes has been disabled. This means that any generation or load that is disconnected from the main island will become de-energized. This prevents incorrect results during the iterated portion of the process if a contingency causes generation or load to be islanded. This also mimics what is done using linear calculations for contingencies that island generation or load.
• Contingency Analysis: When using integrated topology processing, contingency blocks were not being included in determining which breakers should be preserved when using the option to preserve breakers. This could result in incorrect results because all breakers that needed to be opened were not available. This has been fixed.
• General: Fixed bug that was preventing the special contingency options from being available (not grayed out) with Limit Monitoring Settings.
• Linear Sensitivities: Fixed bug that would not allow matrix results for multiple direction PTDFs, matrix LODFs, and multiple TLRs to be returned from SimAuto functions.
• Oneline Diagrams: Fixed bug that would unlink an interface field from the appropriate interface when viewing the interface field dialog.
• Power Flow: Fixed bug associated with equivalencing lines that have the equivalent line ID and non-zero charging values.
• Power Flow: Fixed some errors with custom expressions and custom model expressions to properly identify an expression as not being valid if all variables in the expression are not assigned to valid fields. A blank result for an expression means that the expression is not valid.
• Transient Stability: Prevent user from closing Transient Stability dialog while the analysis is running.

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June 9, 2011

New Features

• Bus View: Default drawing values for generator rotor shape and fill will be used with the Bus View as the default shape. If a fuel type for a generator is specified, the rotor shape will depend on that, but the default drawing values will be used if no fuel type is specified.
• General: Added options when saving a case to force saving the case with comments.
• General: Various dialog messages now distinguish between the various branch device types, i.e. breaker, disconnect, etc., instead of just identifying as a branch.
• Integrated Topology Processing: Branches that are part of an interface will never be consolidated. In order to improve consolidation, if an interface contains a branch that can be consolidated, i.e. breaker, disconnect, etc., but it is in series with a device that cannot be consolidated, i.e. branch, load, gen, etc., the interface will be automatically modified to monitor the device in series instead.

Bug Fixes

• Case Information: Fixed bug with using the filter toolbar and advanced filter dropdown. The dropdown would not allow you to select a filter.
• General: When copying the contents of a case information display to Excel, it was possible that some of the column headers would be missing. This has been fixed.

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June 17, 2011

New Features

• File Formats: Modified to add additional bus labels when reading the MEAS records in the Areva CSV file.
• Oneline Diagram: When clicking on a oneline diagram, substation oneline objects have been modified to give preference for clicking on the substation. If another object overlaps the substation, Simulator will still register the click on the substation now.
• Transient Stability: Added addition model validation for URST5T

Bug Fixes

• Power Flow Solution: Fixed a rare error which could occur if multiple generators existed an island slack bus AND there was a mix of AGC=YES and AGC=NO settings for the generators, AND some generators had a non-zero minimum MW output. This could results in some generators in this grouping going UP while other went DOWN.
• Transient Stability: Fixed error with loading the Transient Limit Monitor's advanced filter from a PWB file. The filter was not properly maintained.
• Transient Stability: Fixed error in initialization of the BBSEX1 and EXBBC exciters.
• Transient Stability: Fixed error in transient simulation when a DC line had Status=CLOSED, but was also BLOCKED.
• Transient Stability: Fixed bug in MAXEX1 and MAXEX2 models
• Transient Stability: Modified the implementation of SVC models so that any step-up transformer associated with the generator model is ignored if their is an SVC model.

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June 30, 2011

New Features

• Contingency Analysis: Added option to use labels in contingency action descriptions. This includes actions shown in the Contingency Definition list and What Actually Occurred.
• File Format: Added an option when saving a RAW file to append object labels as comments to the end of data records.
• File Format: When sending Custom Case Information to Excel, only fields that are text will be marked as text. Previously, the formatting was based on columns being identified as text based fields instead of identifying each individual cell as to whether or not it is text.
• Oneline Diagram: For dynamic formatting purposes, Model Fields will behave like the type of field that they are showing. Thus, a model field showing Area information will behave as though it is an Area Field.

Bug Fixes

• File Format: Fixed a bug reading three winding transformers from PTI contingency file.
• Power Flow: Fixed bug that would incorrectly dispatch MWs for island slack generators with negative minimum MW limits. This bug was introduced in the June 17, 2011 patch with the fix for the error related to dispatching multiple generators at the island slack bus if there was a mix of AGC settings.

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July 7, 2011

New Features

• General: Added the ability with case information displays to show the Super Area in which a generators, loads, switched shunts, and branches are contained.
• Oneline: Modified Line Flow Arrow objects so that the text better aligns with the arrow.
• Power Flow: Added a new field, Enforce Current Limit, with multi-terminal DC line converters. When set to NO, the current limits for the converters will not be enforced. The default setting for this field is YES. When loading multi-terminal DC lines from an EPC file, this option will be set to NO.
• Transient Stability: Added ability to show line relays in the model summary display.

Bug Fixes

• Auxiliary Files: When loading in transmission lines or background lines using a display auxiliary file, the line vertices would not be read correctly if using regional computer settings that use a comma as a decimal symbol instead of a period. This has been fixed.

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July 14, 2011

New Features

• File Formats: Modified the format of the label comment when using the option to append object labels as comments to the end of data records when saving a RAW file.
• Integrated Topology Processing: Added optional parameter, AddCommentsForObjectLabels, to the SaveConsolidatedCase script command. This parameter is set to NO by default. If set to YES and saving to a RAW file, object labels will be added to the end of data records. The new format of the script command is SaveConsolidatedCase(filename,filetype,[BusFormat, TruncateCTGLabels, AddCommentsForObjectLabels]).

Bug Fixes

• Oneline: Modified Line Flow Object so that it can only be clicked on during edit mode so that the lines behind them can be properly clicked on in run mode.
• Power Flow Solution: When using the Scale feature to scale generation in an injection group, enforcing MW limits, and some generators hit limits, the full desired scale amount was not properly achieved. This has been fixed by allocating the portion of the scaling that cannot be accommodated by generators hitting limits to generators that have not yet hit limits.
• Power Flow Solution: When using the Scale feature to scale load in an injection group, maintaining a constant P/Q ratio, and scaling from the present value, the constant P/Q ratio was being applied to the injection group as a whole instead of individual loads. This has been fixed by scaling the Mvar load to maintain the same P/Q ratio at individual loads.
• User Interface Dialogs: Fixed bug that would not allow you to copy from or paste into the Renumber Areas/Zones/Substations dialog.

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August 16, 2011

New Features

• General: Modified the storage of injection groups so that they are stored and maintained in a list sorted by name. This ensures that if 1000s of injection groups are created that it does not slow down loading injection group information.
• Transient Stability: Added full support for the spdmult, UELin and Exclim paramters to ESDC1A and ESDC2A
• Transient Stability: Modified the EXST3 and IEEET1 exciters to add optional spdmult parameter to support the difference between these models in PSLF and PSSE

Bug Fixes

• Available Transfer Capability: When using an injection group as a source in either the PV or ATC ramping and this injection group contained other injection groups with loads, it was possible that the appropriate transfer amount would not be implemented.
• Bus View: When showing the consolidated bus view in a full-topology model bus view, the font color of some fields was not obeying the default colors.
• Case Information: Fixed an access violation that occurred when types were mismatched in a custom expression (like when trying to add a string and an integer together).
• Case Information: Fixed bug so that viewing the differences in column XF Auto for a branch can actually be shown when viewing the difference case.
• Contingency Analysis: When loading the PTI CON file entries for MOVE, entries were always being interpreted as SHUNT moves, so that GENERATOR and LOAD moves were not properly read. This has been fixed.
• File Format: Fixed the handling of how aloss is used to determine the metered point on a multi-section line when reading in the EPC files.
• File Format: Fixed loading of a PWB file to append information to a case to ensure that limitset information is read correctly for Buses, Branches and Interfaces.
• File Format: Fixed loading of a PWB file to append information to a case to that duplicate Injection Groups, Interfaces, Nomograms, and Super Areas are not created.
• File Format: Fixed error in Writing out switched shunts flagged as a Bus Shunt to the EPC file shunt records. If the switched shunt did not contain any blocks it would write out a nominal Mvar of zero.
• Optimal Power Flow: When using the DC approximation and running the OPF or SCOPF, fixed an internal tolerance error which could result in solution never completing.
• PV Curve Tool: When using an injection group as a source in either the PV or ATC ramping and this injection group contained other injection groups with loads, it was possible that the appropriate transfer amount would not be implemented.
• Transient Stability: For GPWSCC, the order of the parameters Kp and Kd were reversed. This has been fixed.
• Transient Stability: Fixed error in REXS to multiply it's output by Efd
• Transient Stability: Fixed error in saving a two-bus equivalent at buses which contained multiple generators.

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August 26, 2011

New Features

• Transient Stability: Created new ESST1A_GE model because PSLF handles input parameters related to the location of the PSS input and UEL input differently than PSSE.
• Transient Stability: Added default columns for present MW and Mvar to Load Characteristic and Load Relay model case information displays.

Bug Fixes

• File Formats: An error could occur if appending a case that contains existing interfaces with a PWB file that also contains interfaces.
• Transient Stability: Fixed error in stabilizers PSSSB, PSS2A, and PSS2B when n=0. This now means the ramp tracking is completely bypassed. Previously setting n=0 was causing simulator to disable the stabilizer completely which was incorrect.

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September 20, 2011

New Features

• Oneline: Fullscreen mode will now use the entire screen obscuring the task bar and any other system toolbars, sidebars, etc.
• PVQV: When reporting switched shunt output in the PV results, the nominal Mvar value will be shown as 0 if the shunt is open.

Bug Fixes

• ATC: In the Distributed ATC process, added better error reporting and fixed the problem where post-contingency auxiliary files were not being sent to the remote processes.
• File Formats: When reading an EPC file, better handle some object ID fields that might be blank that would have caused the file not to load correctly.
• General: Fixed a crash that occurred upon close of the program when using hardware license keys.
• Power Flow: Properly check voltage regulation conflicts so that a generator that is not on AVR control will not cause a switched shunt or transformer that is regulating the same bus to be turned off control.
• PVQV: Better handle the sink injection group hitting limits in the PV tool. Previously, the iterative process that attempts to get the slack change within tolerance and the sink as close to its limit as possible might cut off the transfer change at the wrong point, resulting in the sink not getting as close to its limit within the slack movement tolerance.

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October 11, 2011

New Features

• None.

Bug Fixes

• Contingency Analysis: Display contingency violations correctly when using Integrated Topology Processing. Make sure that the metered flow end of a branch is shown as the actual bus instead of the pnode of that terminal while the case is consolidated.
• File Format: When writing line shunts to an EPC file, retain the original IDs it they contain an f or t. Also, maintain the EPC convention that the f and t indicate the end of the line that the shunt is on. If an ID does not contain an f or t, an appropriate unique ID will be created.
• File Format: Fixed an access violation that could occur when loading an EPC file that contains three-winding transformers with no tertiary winding.
• File Format: Fixed potential bug when loading a RAW file that contains comments. The comments were being included in the count of fields and this could result in an incorrect number of fields being read.
• General: Fixed access violation that could occur when creating calculated fields and using the filtering option to limit objects that are included in the operation.
• General: Modified MoveLineRecord functionality to prevent parallel lines from having the same circuit ID.
• Integrated Topology Processing: Fixed bug that would not pick the correct bus for the superbus pnode. As part of this fix, dead “ground” buses will not be picked as a pnode unless as a last resort.
• Integrated Topology Processing: Display contingency violations correctly when using Integrated Topology Processing. Make sure that the metered flow end of a branch is shown as the actual bus instead of the pnode of that terminal while the case is consolidated.
• Power Flow: Fixed a bug that would not allow an island to become viable even though it contains load by checking the nominal load instead of actual load. The actual load might be zero in a dead island if also using the options for minimum per unit voltage for constant current and constant impedance load due to the voltage at the bus being zero.

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October 18, 2011

New Features

• Oneline Diagrams: When exporting a oneline diagram as a shapefile, added an option for what part of a shape to export as the location of a point. Options are Upper-Left or Center.

Bug Fixes

• Power Flow: Fixed bug that would not do another inner power flow loop even though there are mismatches due to generators hitting var limits after solving the first inner power flow loop AND there are switched shunts controlling generator Mvar output.

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October 27, 2011

New Features

• None.

Bug Fixes

• File Format: When loading in an hdbexport CSV file the owners were being determined incorrectly because we were indexing incorrectly.
• General: Fixed error in Determine Shortest Path Between tool. The shortest path was being determined based on going across lines that should not have been allowed.
• Oneline Diagrams: When using the Actual Value (Weighted Average) and Actual Value (Only Closest) types of values when contouring, GPU acceleration will not be used so that the contour will be displayed as expected.
• Oneline Diagrams: Fixed some artifact problems when using GPU acceleration with contouring.

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November 11, 2011

New Features

• File Formats: When writing out object labels for transformer as comments in a RAW file, modified to make sure the label comment is added at the end of the last line of text representing the transformer.

Bug Fixes

• None.

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November 23, 2011

New Features

• Integrated Topology Processing: When saving the consolidated case along with consolidated contingency list, it was possible for unlinked contingency elements to be written out to the contingency file. This has been fixed.

Bug Fixes

• Integrated Topology Processing: When saving the consolidated case using the check box option "Convert Shunts to Blocks", an access violation could occur causing the export to fail. This has been fixed.
• SCOPF: Fixed a bug which could occur when loading a PWB file that had previously saved Tableua information in it. The maximum number of LP Iterations was then not properly updated and subsequent run of the SCOPF would execute as though the maximum iterations were 99.
• SimAuto: Fixed various GetParameters*() call when using the field format "variable:0:8:4" to specify that 8 digits and 4 decimal points should be returned. Previously it was always returning 12 digits and 6 decimals regardless of user specification. It will now use the specified amount if given, or default back to 12 and 6.

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December 21, 2011

New Features

• 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.

Bug Fixes

• Integrated Topology Processing: Fixed access violation that could occur when saving a consolidated case to file and using the option to "Convert Shunts to Blocks".
• 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.
• User Interface Dialogs: On the Branch Information dialog, fixed a bug reporting the fault currents of the TO end B and C phases in amps. They were being converted to amps on the wrong nominal kV base.

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January 6, 2012

New Features

• None.

Bug Fixes

• Integrated Topology Processing: Fixed a bug that could move devices from their original buses to their pnodes following consolidation and deconsolidation.
• Integrated Topology Processing: Fixed bug that could set switched shunt control mode incorrectly to Fixed if using topology processing along with another add-on that restores system state to the base case state after processing, i.e. contingency analysis, PV, QV, or ATC. This should have only occurred for shunts that were already located at their superbus pnode in the deconsolidated state. This was actually fixed in the November 23, 2011 patch, but the above bug was introduced by that fix. The fix incorporated here fixes both problems.

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January 25, 2012

New Features

• None.

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.
• 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.
• 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.

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New Features/Minor Improvements :

• Auxiliary Files (SCRIPT and DATA Sections)
• Available Transfer Capability (ATC) Tool
• Bus View and Substation View Onelines
• Case Information Displays
• Contingency Analysis Tool
• Fault Analysis
• File Formats
• General
• Help
• Integrated Topology Processing (ITP)
• Model Explorer
• Oneline Diagrams
• OPF Reserves Tool
• Optimal Power Flow (OPF)
• Power Flow Solution
• PV and QV Curve (PVQV) Tool
• Security Constrained OPF (SCOPF) Tool
• Sensitivity Calculations
• Simulator Automation Server (SimAuto)
• Time Step Simulation
• Transient Stability
• User Interface Dialogs

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Auxiliary Files (SCRIPT and DATA Sections)

• (July 9, 2010) Added new script command "AutoInsertTieLineTransactions" which takes now parameters. This deletes all existing MW transactions and set the unspecified MW interchange for each area to zero. It then automatically creates a MW transaction between each pair of connected areas with a MW transaction exactly equal to the sum of the tie-line flows.
• (August 4, 2010) When using the MergeLineTerminals() script command, we now send a message to the log if no lines are actually selected for merging.
• (August 11, 2010) Added a new script command "InjectionGroupsAutoInsert;". This passes no parameters. The options for this command can be set by populating the object "IG_AutoInsert_Options" appropriately. The settings available with this object represent what is seen on the Auto Insert Injection Groups Dialog.
• (September 21, 2010) Added support for general script commands in the AXD file format to manipulate oneline diagram objects. The following commands can be used: ExitProgram, LoadScript, LoadData, SelectAll, UnSelectAll, SaveData, SaveDataWithExtra, CreateData, DeleteFile, RenameFile, CopyFile, SetCurrentDirectory, and SaveObjectFields.
• (September 21, 2010) The field "Selected" can now be used with oneline display objects. This can be used in the script section for AXD files.
• (September 27, 2010) Modified the editing of data in a case information display (or through an AUX file) so that the string "&ModelExpressionName:8:4" can be entered. A string which starts with the character & will be treated as though the value of the named model expression is being entered in the field. The format of the string will be determine by the last two integer values representing the total number of digits and decimal places.
• (November 17, 2010) Added a new file type to the SaveData() script command called "CSVColHeader". When using this file type, the file will be written with the first row showing column headers you would see in a case information display. The file type "CSV" will always show variable names.
• (November 17, 2010) Added a support for the new file type "CSVColHeader" to the SaveDataWithExtra() script command also.
• (November 17, 2010) Added the script command SendToExcel(ObjectType, [FieldList], Filter, UseColumnHeaders, "WorkBookName", "WorkSheetName") to mimic the behavior of Send to Excel option within a case information display. The first three parameters behave the same as for many other scripts. The UseColumnHeaders parameter should be passed as a YES to signify that the first row shows Column Header or NO to signify that variable names be used. The last two parameters specify the WorkBook Name and the WorkSheet and are optional parameters. If they are blank then a new workbook or worksheet will be created. If a value is specified it will overwrite the existing data in the workbook or worksheet.
• (November 23, 2010) Added new script command to find branches that create islands.
• (December 1, 2010) Added new script command DetermineBranchesThatCreateIslands(BranchesToProcess, StoreBuses, "FileName", SetSelectedOnLines);
  This script action determines the branches whose outage results in island formation. There are options to specify the branches to process, whether or not to store the islanded buses to the output file, the output filename, and an option to set the selected flag on branches that create islands. Note that setting the Selected field will overwrite the Selected fields.
  BranchesToProcess: The branches to consider while determining outages that create islands. ALL: consider all branches SELECTED: consider branches with a selected flag set to true AREAZONE: consider branches meeting AREA/ZONE filters "Filtername": consider branches that meet the filter given in filtername. Note that a valid branch fliter with the name specified by filtername must exist. StoreBuses: YES or NO field that specifies whether the buses in the island are stored in the output file. The output file is an aux file. The branches that create islands are stored in a single data section. When the buses are also stored, the buses are in a data section immediately following the branch data section, so there is a pairing between the outaged line(s) and the islanded buses.
  "Filename" : the name of the file to which the output will be stored. If the filename is empty ("") or simply blank, then the results will not be stored in a file. This will only be useful if the results are stored in the Selected field for the branches instead.
  SetSelectedOnLines: YES or NO field that determines if the SELECTED field will be set to YES for branches that create islands.
• (December 10, 2010) Modified the Move() script command to permit you to move a MULTISECTIONLINE. The format is the same as for moving a regular branch except that the object name should be MULTISECTIONLINE.
• (December 28, 2010) Added a new script command called "StopAuxFile". This command will effectively treat the remainder of the file after this command as a big comment. This includes any script commands inside the present SCRIPT block, as well as all remaining SCRIPT or DATA blocks.
• (February 22, 2011): New script command called.
  AutoInsertBorders;
  which uses the AutoInsertBordersOptions object to set the options.
• (February 22, 2011): New script command called.
  AutoInsertBuses(Location Source,Map Projection, AutoInsertBranches, InsertIfNotAlreadyShown, “FileName”, FileCoordinates);
  Location Source – "Bus","Substation", "File"
  Map Projection – "Simple Conic", "Mercator", "x,y"
  AutoInsertBranches – YES or NO if transmission lines should be inserted when finished
  InsertOnlyIfNotAlreadyShown – YES if only buses that are not already shown should be inserted, NO if all buses should be inserted
  "FileName" – optional if Location Source is File. File containing the bus locations.
  File Coordinates – optional if Location Source is File. "x,y" or "lon,lat"
• (February 22, 2011): New script command called.
  AutoInsertLoads(MinkV, InsertTextFields, InsertEquivObjects);
  minKV = Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to insert Text Fields | Default Value = Yes
  InsertEquivObjects = optional field regarding whether to insert Equivalenced Objects | Default Value = Yes
• (February 22, 2011): New script command called.
  AutoInsertGens(MinkV,InsertTextFields);
  minKV = Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to insert Text Fields | Default Value = Yes
• (February 22, 2011): New script command called.
  AutoInsertSwitchedShunts(MinkV, InsertTextFields);
  minKV = Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to insert Text Fields | Default Value = Yes
• (February 22, 2011): New script command called.
  AutoInsertLines(MinkV, InsertTextFields, InsertEquivObjects, InsertZBRPieCharts, InsertMSLines, ZBRImpedance, NoStubsZBRs, SingleCBZBRs);
  minKV = optional field for Minimum KV Level | Default Value = 0
  InsertTextfields = optional field regarding whether to Insert Text Fields | Default Value = Yes
  InsertEquivObject = optional field regarding whether to Insert Equivalenced Objects | Default Value = Yes
  InsertZBRPieCharts = optional field regarding whether to Insert pie chasrt for lines with no limit and bus ties | Default Value = No
  InsertMSLines = optional field regarding whether to Insert Multi Section Lines | Default Value = Yes
  ZBRImpedance = optional field regarding whether to Maximum P.U. Impedance for Bus Ties | Default Value = 0.0001
  NoStubsZBRs = optional field regarding whether to Do not Insert Stubs for bus ties | Default Value = Yes
  SingleCBZBRs = optional field regarding whether to Only Insert a single circuit breaker | Default Value = Yes
• (February 22, 2011): New script command called.
  AutoInsertLineFlowObjects(MinkV, InsertOnlyIfNotAlreadyShown, LineLocation, Size, FieldDigits, FieldDecimals, TextPosition, ShowMW, ShowMvar, ShowMVA, ShowUnits, ShowComplex);
  minKV Minimum KV level | Default Value = 0
  InsertOnlyIfNotAlreadyShown = optional field regarding whether to insert if Existing line flow object exist, do not auto insert new ones
  LineLocation = optional field regarding whether to Where to insert flow objects : 0 - Middle, 1 - 10%/90%, 2 - After Stubs
  Size = optional field for Size | Default Value = 5.0
  Fielddigits = optional field for Total Field in Digits | Default Value = 6
  FieldDecimals = optional field for Digits to right of decimal | Default Value = 2
  Textposition = optional field for Flow Text position above: Yes - above, No – below | Default Value = Yes
  Showmw = optional field for Show MW | Default Value = Yes
  Showmvar = optional field for Show Mvar | Default Value = Yes
  Showmva = optional field for Show MVA | Default Value = Yes
  Showsuffix = optional field for Show Units | Default Value = Yes
  Showcomplex = optional field for Show Complex (MW + jMvar) | Default Value = No
• (February 22, 2011): New script command called.
  AutoInsertSubstations(Location Source,Map Projection, AutoInsertBranches, InsertIfNotAlreadyShown, “FileName”, FileCoordinates);
  Location Source – "Substation", "File"
  Map Projection – "Simple Conic", "Mercator", "x,y"
  AutoInsertBranches – YES or NO if transmission lines should be inserted when finished
  InsertOnlyIfNotAlreadyShown – YES if only substations that are not already shown should be inserted, NO if all substations should be inserted
  "FileName" – optional if Location Source is File. File containing the substation locations.
  File Coordinates – optional if Location Source is File. "x,y" or "lon,lat"
• (February 22, 2011): New script command called.
  AutoInsertLineFlowPieCharts(MinkV, InsertOnlyIfNotAlreadyShown, InsertMSLines, Size);
  minKV Minimum KV level | Default Value = 0
  Size = optional field for Size | Default Value = 5.0
  InsertOnlyIfNotAlreadyShown = optional field for If existing line flow objects exist, do not auto insert new ones | Default Value = Yes
  InsertMSLines = optional field for Insert Multi-Section Line Flow Objects if applicable | Default Value = Yes
• (February 22, 2011): New script command called.
  AutoInsertInterfaces(InsertPieCharts, PieChartSize);
  InsertPieCharts = optional field for Insert pie Charts on Interfaces | Default Value = Yes
  PieChartSize = optional field for Default Size of interface Pie Charts | Default Value = 50.0
  Note: Only creates for interfaces that contain an Area to Area element or a Zone to Zone Element
• (February 22, 2011): New script command called.
  ResetStubLocations(ZBRImpedance,NoStubsZBRs);
  ZBRImpedance = optional field for Max P.U. Impedance for Bus Ties | Default Value = 0.0001
  NoStubsZBRs = optional field for Do not insert stubs for bus ties | Default Value = Yes
• (April 5, 2011) Added optional parameter to SaveCase script command for use when saving an EPC file. New format is SaveCase("filename",SaveFileType,[PostCTGAGC, UseAreaZone]); PostCTGAGC by default is set to NO. Set to YES to set the base load flag in the EPC file based on the Post-Contingency Prevent AGC Response setting. If preventing post-contingency AGC, the base load flag is set to 1. If not preventing post-contingency AGC or this option is set to NO, the base load flag is set to 0. UseAreaZone by default is set to NO. Set to YES to limit the entries in the EPC file based on the area/zone/owner filter.
• (April 12, 2011) Added a new script command called "SetGenPMaxFromReactiveCapabilityCurve(filter);". For generators which use a capability curve, the script will change the Maximum MW output of the generator to be equal to the second-to-last MW point on the capability curve if the last Max Mvar point on the capability curve is smaller than 0.001 Mvar. (Also if the present MW output is higher than this new Max MW value, then Max MW is set to the present MW output). The filter parameter is optional and uses the standard filter options of Selected, AreaZone, or "AdvancedFilterName". If omitted, then all generators are processed.
• (March 31, 2011) New script command SetScheduledVoltageForABus([bus identifier], voltage). This command sets the stored scheduled voltage, vsched, for a bus according to how this is defined in the EPC format. This value is not used by Simulator but is stored for purposes of writing out to an EPC file. The setpoint voltages for generators and switched shunts regulating the specified bus are also set to the new voltage. The regulation range for switched shunts are modified for the new setpoint voltage according to how this is defined in the EPC format: vband = (VHigh-Vlow)/2 with newVHigh = voltage + vband and newVLow = voltage - vband.

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Available Transfer Capability (ATC) Tool

• (August 11, 2010) Optimized the code for the calculate of ATC values to pre-calculate the Line Outage/Insertion sensitivities prior to running the ATC. This increased the speed of the single linear step ATC method by about a factor of 2. Increases the total speed of the iterated methods by about a factor of 3.
• (September 10, 2010) Modified internal numerical routines to make them faster.
• (September 21, 2010) Continuing to improve speed of the ATC calculation.
• (September 27, 2010) More modifications for speed of the ATC tool. The overall speed increase from the initial release of Simulator 15 is now between 2 and 6 times for the iterated solution methods and between 4 and 10 times for the Single Linear Step solution methods.
• (November 17, 2010) Added a new option to linearize the calculation of contingency makeup power. This will precalculate the impact of makeup power on line flows at the start of the analysis and then the total effect of makeup power will be determined by multiplying the effect on a line by the Total amount of Makeup power needed. This calculation will be slightly faster than previous calculation of makeup power, but it will not take into account the fact larger amounts of makeup power may cause particular generators to hit min or max limits.
• (April 5, 2011) Removed the option Apply PTDF Cutoff for Limiting Elements with Contingencies. It really didn’t make any sense to eliminate limiters that are limiting during a contingency if they are not limiting in the base case.

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Bus View and Substation View Onelines

• (April 5, 2011) Now storing option settings for displaying MW branch, Mvar branch, and MW interface flows in absolute value in the registry. The values stored in the registry will be used as the defaults for these settings when oneline options don’t exist for the Bus View or Substation View with the power flow case (PWB).
• (June 9, 2011) Default drawing values for generator rotor shape and fill will be used with the Bus View as the default shape. If a fuel type for a generator is specified, the rotor shape will depend on that, but the default drawing values will be used if no fuel type is specified.

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Case Information Displays

• (July 7, 2010) Added ability to use other object type filters with the GenVarLim object.
• (August 11, 2010) Add ability to define "Custom String Expressions" which represent the concatenation of strings from the columns of an object. Included in the was a new function available in the expression string with format "Str(x1, minlength, decimals)" where x1 represents a numeric variable, minlength represents the minimum number of characters for the result, and decimals represents the number of characters to the right of the decimal point.
• (September 22, 2010) When choosing "Send to Excel", Simulator will now programatically set Excel to NOT "treat consecutive limiters as one". It also ensures that some "Other" character is not being used as a delimiter so that only TAB characters are used.
• (September 27, 2010) Modified the editing of data in a case information display (or through an AUX file) so that the string "&ModelExpressionName:8:4" can be entered. A string which starts with the character & will be treated as though the value of the named model expression is being entered in the field. The format of the string will be determine by the last two integer values representing the total number of digits and decimal places.
• (October 6, 2010) The Transformer Configuration Field is now enterable and toggleable on a case information display.
• (October 15, 2010) Modified the custom expression parser to allow a floating point to be specified as ".05" or "0.05". Previously the ".05" would cause the parser to fail.
• (October 15, 2010) Modified case information displays show that when showing a value such as -0.01 which is truncated to fewer decimal places, the resulting string will still include the negative sign and show "-0.0" for example instead of "0.0".
• (November 17, 2010) In a Custom String Expression, when using the Str(Value, Digits, Decimals) function, if the Decimals parameter is specified as negative, then it will truncate all trailing zeros beyond the decimal.
• (January 28, 2011) Modified the right-click menu for case information displays so that if no substations exist, then the Sub View is not enabled.
• (March 15, 2011) Added fields for Owner records showing the Number of Branches by Type (Transformer, Line, SeriesCap, Breaker, Disconnect), and the number of switched shunts.
• (March 24, 2011) Added fields for injection groups that list Area/Zone/Owner of all of the devices in the injection group. Fields are available for listing either the number or name of the associated Area/Zone/Owner.
• (December 21, 2011) 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.

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Contingency Analysis Tool

• (March 24, 2011) Two different types of fields are now available with contingencies to list the Areas/Zones/Owners associated with the elements of the contingency. Fields exist for listing either the number or name of the associated Areas/Zones/Owners. Fields that are labeled with “recurse” will look inside injection groups, interfaces, and contingency blocks for identifying the associated Areas/Zones/Owners. Fields without “recurse” will not look inside injection groups, interfaces, or contingency blocks.
• (June 30, 2011) Added option to use labels in contingency action descriptions. This includes actions shown in the Contingency Definition list and What Actually Occurred.

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Fault Analysis

• (September 28, 2010) Added total fault impedance field to TBus, to store the thevenin R and X needed to calculate the total fault X/R ratio.

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File Formats

• (June 25, 2010) When using the Present Topological Differences from Base Case tool, added the ability to save the removed elements in the EPC file format using status values of -4.
• (July 7, 2010) When loading the hdbexport file, modified to automatically add two labels to each transmission line. One label starts with the "from" substation name and the other label starts with the "to" substation name.
• (July 9, 2010) Modified the writing of PTI RAW files so that switched shunt records always write out at least one block. If none exists, a single block with 1 step and size equal to the present MVar output is written.
• (July 7, 2010) Modified the writing of GE EPC file so that Multi-Terminal DC converters will write out the "aloss" parameter in a manner consistent with how the EPCL file mtTAP.p expects to ensure the EPCL operates appropriate for WECC data files.
• (August 11, 2010) When reading from an EPC file, added the reading of the area and zone designation of a GE branch and transformer. This will not be stored in the PWB file format for now but will be added to Version 16's format.
• (September 3, 2010) Added a log warning message when appending an EPC file which causes a transformer branch to be converted to a normal branch.
• (October 6, 2010) When loading in EPC files and the latitude and longitude values are both zero, both entries will be ignored as invalid.
• (November 17, 2010) When appending using the RAW file format, we now populate a field to say whether an object is new or modified while reading.
• (December 1, 2010) When appending an EPC file with a scheduled voltage for a bus, the voltage setpoints for switched shunts and generators that are regulating this bus are now properly updated.
• (December 28, 2010) When appending to an existing case using an EPC file or a RAW file, any new branches that are created are now flagged as having just been added. This flag is then used as part of the pre-processing feature in the power flow solution to automatically estimate appropriate voltage magnitudes and angles for any existing or new buses that become newly energized.
• (January 5, 2011) Modified how appending an existing three-winding transformer is handled if a new three-winding transformer is entered which uses a bus number which is already used as a star bus by another transformer. This is not allowed and a new bus number will automatically be chosen.
• (January 28, 2011) When loading a RAW or EPC file, the participation factor for generators at a slack bus were set to zero. This has been changes so slack generators are set the same as other generator (MBase/SBase)
• (June 17, 2011) Modified to add additional bus labels when reading the MEAS records in the Areva CSV file.
• (June 30, 2011) Added an option when saving a RAW file to append object labels as comments to the end of data records.
• (June 30, 2011) When sending Custom Case Information to Excel, only fields that are text will be marked as text. Previously, the formatting was based on columns being identified as text based fields instead of identifying each individual cell as to whether or not it is text.
• (July 14, 2011) Modified the format of the label comment when using the option to append object labels as comments to the end of data records when saving a RAW file.
• (November 11, 2011) When writing out object labels for transformer as comments in a RAW file, modified to make sure the label comment is added at the end of the last line of text representing the transformer.

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General

• (January 5, 2011) Modified how Simulator handles setting its Windows Operating System Priority so that the user can change this. The only exception is that while animating, Simulator alwasy sets its Priority to Low to ensure that the animation does not interfere with other programs.
• (April 5, 2011) Amps field is now available with loads.
• (June 9, 2011) Added options when saving a case to force saving the case with comments.
• (June 9, 2011) Various dialog messages now distinguish between the various branch device types, i.e. breaker, disconnect, etc., instead of just identifying as a branch.
• (July 7, 2011) Added the ability with case information displays to show the Super Area in which a generators, loads, switched shunts, and branches are contained.
• (August 16, 2011) Modified the storage of injection groups so that they are stored and maintained in a list sorted by name. This ensures that if 1000s of injection groups are created that it does not slow down loading injection group information.

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Help

• None.

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Integrated Topology Processing (ITP)

• (January 28, 2011) Added a new field for object types Branch, Gen, Load, Shunt, and DCLine which shows the "Derived Status". For full topology power system models, this field will show whether the breakers adjacent to a device are OPEN or CLOSED. If the device is energized, the field will always show CLOSED. If the device's actual Status is OPEN, the field will alway show OPEN. If the device's actual status is CLOSED, but the device is not energized, the software will determine if any adjacent Breaker objects are CLOSED in which case the derived status will show CLOSED - otherwise it will show OPEN.
• (June 9, 2011) Branches that are part of an interface will never be consolidated. In order to improve consolidation, if an interface contains a branch that can be consolidated, i.e. breaker, disconnect, etc., but it is in series with a device that cannot be consolidated, i.e. branch, load, gen, etc., the interface will be automatically modified to monitor the device in series instead.
• (July 14, 2011) Added optional parameter, AddCommentsForObjectLabels, to the SaveConsolidatedCase script command. This parameter is set to NO by default. If set to YES and saving to a RAW file, object labels will be added to the end of data records. The new format of the script command is SaveConsolidatedCase(filename,filetype,[BusFormat, TruncateCTGLabels, AddCommentsForObjectLabels]).
• (November 23, 2011) When saving the consolidated case along with consolidated contingency list, it was possible for unlinked contingency elements to be written out to the contingency file. This has been fixed.

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Model Explorer

• None.

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Oneline Diagrams

• (June 25, 2010) When using a contour with a dynamic interpretation, if all the values being contoured had the same value the contour image could appear random. This was remedied by enforcing a minimum tolerance on the separation between minimum, nominal, and maximum values of the color map.
• (July 16, 2010) Added a Simulator Oneline option that alter how Simulator responds when click on a circuit breaker symbol for a generator display object. Normally the generator's status is set to closed and the MW value is reset to its previous value. The new option allows the value to be set to its minimum MW output instead.
• (August 11, 2010) When changing to a Saved View which specifies that a contour be shown, we now automatically refresh the contour image.
• (August 30, 2010) Added ability to export a oneline diagram as a GIF image.
• (August 30, 2010) Added ability to export a oneline diagram as an animated GIF image (animated the arrows and generator rotors).
• (December 10, 2010) When opening a oneline diagram using the AXD format, if no Saved View named THIS_VIEW_IS_APPLIED_TO_THE_CURRENT_DISPLAY is specified, then a Show Full will automatically occur for the oneline.
• (March 31, 2011) Store default filetype (number, name_kV linking, label linking, or AXD) to make it easier to open subsequent onelines using the same filetype.
• (June 17, 2011) When clicking on a oneline diagram, substation oneline objects have been modified to give preference for clicking on the substation. If another object overlaps the substation, Simulator will still register the click on the substation now.
• (June 30, 2011) For dynamic formatting purposes, Model Fields will behave like the type of field that they are showing. Thus, a model field showing Area information will behave as though it is an Area Field.
• (July 7, 2011) Modified Line Flow Arrow objects so that the text better aligns with the arrow.
• (September 20, 2011) Fullscreen mode will now use the entire screen obscuring the task bar and any other system toolbars, sidebars, etc.
• (October 18, 2011) When exporting a oneline diagram as a shapefile, added an option for what part of a shape to export as the location of a point. Options are Upper-Left or Center.

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OPF Reserves Tool

• None.

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Optimal Power Flow (OPF)

• None.

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Power Flow Solution

• (September 22, 2010) After treating Discrete Switched shunts as continuous shunts in the inner power flow loop, Simulator sets nominal Mvar output to one of the discrete options available. Previously it was biased to set higher Mvar values such that anything at least 5% of the way toward a higher block would switch to the higher block. This has been changed to no longer bias the switching and instead just round to the nearest block.
• (September 28, 2010) Modified slightly when generator limits are checked. Previously they would be checked "immediately" (i.e. inside the inner power flow loop) if the mismatch fell below 0.02 per unit (2 MW or 2 Mvar normally). This could lead to some inconsistent results if in one situation the mismatch when from 2.001 to near zero, and in another it went from 1.999 to near zero. Simulator will now only check generator limits inside the inner power flow loop if the user chooses the "check immediately" solution option.
• (September 28, 2010) Switched back to old way (before September 22) of handling discrete shunts as continuous.
• (December 10, 2010) Modified the algorithm which automatically chooses a slack bus when a new island is created. Previously, if possible, it would always choose a bus which had generation that regulated its own terminal bus. Now it is biased to do this, but if another bus with generation that does not regulate its terminal bus is available and this other bus has a maximum MW output that is 5 times higher, it will be chosen.
• (December 28, 2010) When pre-processing the voltage profile of a solution before solving, Simulator will now look at groupings of buses connected by very low impedances lines. If a bus in a grouping of energized buses has a zero voltage while other buses in the group do not, the zero voltage will be changed to the first non-zero voltage found in the grouping. This provides a much more reliable solution.
• (July 7, 2011) Added a new field, Enforce Current Limit, with multi-terminal DC line converters. When set to NO, the current limits for the converters will not be enforced. The default setting for this field is YES. When loading multi-terminal DC lines from an EPC file, this option will be set to NO.
• (October 18, 2011) Fixed bug that would not do another inner power flow loop even though there are mismatches due to generators hitting var limits after solving the first inner power flow loop AND there are switched shunts controlling generator Mvar output.

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PV and QV Curve (PVQV) Tool

• (July 2, 2010) With the PV tool added the options to interpolate inadequate voltages and to always report the minimum voltage when monitoring low limit violations even if no limits are violated.
• (August 4, 2010) When exporting QV results to a CSV file, all results are now sorted by the voltage setpoint.
• (August 12, 2010) Added the ability to plot multiple QV curves on the same plot.
• (August 24, 2010) The more flexible plotting environment available in Transient Stability has been integrated into the PV Curve tool. This is available under "New Plots" on the PV Curve dialog. Note that this is available in addition to the previous plotting tool.
• (September 21, 2010) PV Curve Tool state archiving is now available when using Integrated Topology Processing.
• (October 6, 2010) Nominal Shift field is now included in the PV output file. Previously, only the Export and Import fields were included sometimes making it difficult to match up results between a scenario and the base case.
• (December 28, 2010) Optimized the solution speed of the PV and QV curves tools. The QV curve especially should run much more quickly, especially on cases smaller than a few thousand buses.
• (May 5, 2011) Added a new YES/NO optional parameter to PVWriteResultsAndOptions("filename", AppendFile). Specifying NO will cause it to overwrite the existing file. Specifying YES will cause it to append to the file. If not specified, then YES is assumed.
• (March 31, 2011) Attempt to speed up the process of determining how much additional var support is necessary for the power flow solution to converge when a contingency will not solve in the base case. Now look for the solvable point by tracing the QV curve from the present base case voltage up to the maximum voltage instead of tracing from the present base case voltage down to the minimum voltage.
• (September 20, 2011) When reporting switched shunt output in the PV results, the nominal Mvar value will be shown as 0 if the shunt is open.

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Security Constrained OPF (SCOPF) Tool

• None.

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Sensitivity Calculations

• (July 23, 2010) Greatly increased the speed of calculating multiple element TLR sensitivities.
• (September 10, 2010) Modified internal numerical routines to make solutions faster.
• (February 22, 2011) Added interface fields for showing the LODF and the Post-CTG MW flow (after Line outage) values similar to those presently available for a branch.
• (February 28, 2011) Previously it was only possible to open one instance of the the LODF dialog at a time. This was because only one LODF result was stored so performing the calculation on one dialog changed the results on other open dialogs even if the chosen branch did not change on the other dialogs. This caused confusion and thus resulted in us restricting to one one LODF dialog. This has now been modified to allow two LODF dialogs to be open simultaneously, but when doing this Simulator forces one dialog to show a "Single LODF" calculation, while the second dialog shows the "LODF Matrix". This is less confusing because the "LODF matrix" results are stored separately and thus can be displayed separately.
• (February 28, 2011) Same modification done for PTDF dialog by restricting the first dialog to "Single" Directions, while the second dialog shows "Multiple" directions.
• (February 28, 2011) Same modification done for TLR/GSF dialog by restricting the first dialog to the "Line/XFMR or Interface" device type, while the second dialog shows "Multiple Elements" device type.

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Simulator Automation Server (SimAuto)

• (October 6, 2010) Labels now supported in SimAuto functions ChangeParametersSingleElement, GetParametersSingleElement, and GetParametersMultipleElement.
• (February 15, 2011) Modified the Time Step processing when using the SCOPF algorithm at each time step so that less messaging is sent to the Time Step dialog regarding the progress of the sCOPF solution. All the messaging to status edit boxes on the Time Step dialog was greatly slowing down the solution process.
• (February 15, 2011) When using the DC-Approximation, modified the SCOPF dialog so that less messaging is sent to the SCOPF dialog regarding the progress of the sCOPF solution. All the messaging to status edit boxes on dialog was greatly slowing down the solution process.

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Time Step Simulation

• (November 17, 2010) Added the storage of the Custom Inputs to the TSB file format.
• (November 17, 2010) Added the storage of the Custom Results for Loads to the TSB file format.
• (April 5, 2011) When using the column plotting option to plot time points, time scale will now be in seconds if no difference between time points is greater than one minute.

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Transient Stability

• (June 25, 2010) Modified storage to RAM to automatically include any information needed for a subplot's horizontal axis data.
• (July 16, 2010) Modified the Generator and Load dialogs to be sizeable when on the Transient Stability Tab.
• (July 16, 2010) Modified the Plot Designer portion of the dialog to have scroll bars
• (July 16, 2010) Added the ability to add to a Plot a Title Block including an image logo, text, and a date.
• (July 16, 2010) Added ability to copy to clipboard or print a plot including the Title Block and multiple subplots.
• (July 16, 2010) Added ability to close all open plots from the local menu of a plot and from a button on the Transient Stability dialog.
• (July 16, 2010) Modified GENCC generators to require an Xcomp value which is negative.
• (July 16, 2010) Modified the loading of GE DYD files to also accept a file extension of "DYC". When loading a DYC file no prompt will appear asking about deleting existing stability models. The assumption is that it will append to existing models.
• (August 4, 2010) When loading in synchronous machine saturation values specified at 1.0 and 1.2 per unit, if S(1.2) < S(1.0) then Simulator will flip the values to autocorrect.
• (August 11, 2010) When writing out DYD files, we now always write out the model names in lower case characters.
• (August 11, 2010) When write out two bus equivalent models from the SMIB portion of the dialog, generators are now automatically set to AVR = NO.
• (August 11, 2010) Modified to automatically refresh any open plots when performing the interval check while running transient stability. Previously it would only refresh plots if the option was set to "Transfer Results to Power Flow after Interval Check"
• (August 11, 2010) Modified the user interface throughout Simulator to not allow editing of the power system data when you've transferred the transient stability state over to the power flow. Case Information displays will appear yellowed and editing on most power system model dialogs will not be allowed.
• (August 11, 2010) Added ability to open only one end of a transmission branch.
• (August 11, 2010) Fixed bug when using the default (done by specifying a negative gv1 value) non-linear steam gate function for the IEEEG1 governor.
• (August 24, 2010) For the IEEEG1 governor model, the following two relationship must be true. K1+K3+K5+K7=1 and K2+K4+K6+K8=1. If they are not true, Simulator will now normalize the values to enforce these equalities.
• (August 24, 2010) When choosing to show a transient stability plot on the execution of the stability run, the simulation will now automatically update the plots with appropriate data after each interval check. Previously the user would also have to specify this update if they want the plots to actually show data.
• (August 30, 2010) Added toolbars to the generator's SMIB dialog which shows details on the generator eigenvalues.
• (August 30, 2010) Modified the labels on the axis to change format by default as appropriate. Thus if the absolute value of minimum and maximum values are both less than 0.01 it will automatically switch to scientific notation. This will also happen if both min/max are either greater than 10,000 or less than -10,000.
• (August 30, 2010) Added ability to store results for the apparent power at the from and to ends of a branch.
• (August 30, 2010) When choosing to store results to the Hard Drive, previously if no directory was specified to which results should be saved then results would not be saved to hard drive at all. Now if the directory is blank, Simulator will default to save data in the same directory as the case was loaded from. Note that if an invalid directory is specified it will still not save results.
• (August 30, 2010) Modified the generator fields for Maximum Frequency and Minimum Frequency to show actual frequency instead of the deviation from nominal.
• (September 3, 2010) 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.
• (September 3, 2010) Added full support for the LDFR load characteristic model.
• (September 3, 2010) Added read/write support for the CSTATT model.
• (September 21, 2010) Modified the internal storage of the list of Transient Contingencies so that they are sorted. When creating a large number of them (1000s) this is required to improve the speed of reading/writing information from auxiliary files.
• (September 21, 2010) Added full support for the WT2T, WT2P, and WT2G wind turbine models.
• (September 21, 2010) Added better reporting of loads that don't initialize.
• (September 22, 2010) Improving error messeges when the stability simulation aborts.
• (October 1, 2010) Added more validation checks to ensure that only appropriate groupings of wind models are used such as GEWTG/EWTGFC/WNDTGE, GEWTG/EXWTGE/WNDTGE, and GENWRI/EXWTG1/WNDTRB. This help prevent input errors such as using the full converter electrical model (EWTGFC) with a machine model configured as a DFAG (fcflg = 0).
• (October 15, 2010) For plots, add the ability to specify special strings such as "@CTGName" which will automatically determine an appropriate string to place in the Plot Title Block Memos, Axis Title captions, Chart Title, or Chart Footer. @CTGNAME will display the appropriate contingency name; @CASENAME will show the name of the case presently open; @BUILDDATE will show the Simulator patch build date; @DATETIME will show the present date and time; @DATE will show the present date; @TIME will show the present time.
• (October 28, 2010) Added validation check for the ESAC8B model to ensure that both Kir=0 and Kpr=0 is not allowed. The auto-correction will change Kpr to 40 if both are zero.
• (October 28, 2010) When showing plots in the transient stability dialog Simulator now remembers the size and location of the plot window if you change it. When showing a plot on subsequent stability runs during that session of Simulator the size and location will be remembered.
• (October 28, 2010) Added validation check for ropen and rup to be positive numbers and rclose and rdown to be negative numbers.
• (October 28, 2010) Added more error checking with IEEEST stabilizer model when A2/A4 values are small.
• (October 28, 2010) Added use of 8 subintervals of integration for the EXAC1 model if Ka/Ta is larger than 10,000
• (October 28, 2010) Fixed small time constant issue with ESAC8BGE model
• (October 28, 2010) Added read/write support for the HYGOVR model (implementation in dynamic simulation is not completed yet).
• (November 17, 2010) Added support for the HYGOVR governor.
• (November 17, 2010) Added showing the bus frequency on the Transient Load Dialog.
• (November 17, 2010) Added ability to specify whether to use the Runga-Kutta Order 2 (RK2) or Eulers method for the integration time step.
• (November 23, 2010) Added a new option to specify the type of saturation function to use for an exciter model. Choices are Quadratic, Scaled Quadratic, or Exponential.
• (November 23, 2010) When loading a PSLF DYD file, modified to specify that the Quadratic exciter saturation function be used.
• (November 23, 2010) When loading a PSS/E DYR file, modified to specify that the Scaled Quadratic exciter saturation function be used.
• (November 23, 2010) When loading a IPF SWI file, modified to specify that the Exponential exciter saturation function be used.
• (November 23, 2010) Modified the captions of plots to use identifiers as specified by the "Identify Buses in Events and Results by" option.
• (December 10, 2010) When modeling a GENCLS model with H=0 and D=0 it is now treated as an infinite bus.
• (December 10, 2010) Modified two bus equivalent saved from the SMIB portion of the dialog, we now save a GENCLS model on the slack bus saved to represent an infinite bus.
• (December 10, 2010) Added the ability to read a "DYR file with options". When choosing this, you may specify a MCRE *.rwm file to split up generators, a MTRLD *.dat file to split up motors, a GNET *.idv file to disable generator models, and a BASEGEN *.dat to specify the Governor Response Limits flag for generators.
• (December 10, 2010) When writing out a DYR file, we now automatically write out a GNET *.idv and a BASEGEN *.dat file. The filename and patch used will be the same as for the DYR file, except "_GNET" and "_BASEGEN" are appended to the filenames.
• (December 28, 2010) Added an appropriate error message when the transient stability aborts due to a failed network equation solution.
• (December 28, 2010) Added read/write support for the LD1PAC load model, which is used to represent small air conditioner load.
• (December 28, 2010) Added full support to TGOV5 and set the defaults for boiler-follow control.
• (December 28, 2010) Added full support for the CSTATT static condensor model
• (January 5, 2011) Added a new transient contingency event for "OPEN BUS" which opens all AC lines connected to a bus.
• (January 5, 2011) Modified the transient limit monitors to allow an option to "Trip (Open) Device" if a monitoring violation occurs. This works for Buses, AC Lines, Generators, Loads, and DC Lines.
• (January 5, 2011) When choosing to load a DYR file using options, we now auto-populate the various GNET, MTRLD, BASEGEN, and MCRE file if a file with appropriate name exists.
• (January 14, 2011) Added the ability to automatically save plot images during a transient stability run. The images will be saved in the same directory as the defined hard-drive storage directory.
• (January 28, 2011) Added the ability to load the MCRE, MTRLD, GNET, and BASEGEN files each separately if desired.
• (January 28, 2011) Added new script commands for Transient Stability Tool which are all available in the PowerFlow submode.
• (January 28, 2011) TSSolveAll - Solves all specified transient contingencies.
• (January 28, 2011) TSSolve("ContingencyName", [StartTime, StopTime, StepSize]) - Solves only the specified transient contingency. StartTime, StopTime, and Stepsize are specified in seconds.
• (January 28, 2011) TSWriteOptions("FileName", [opt1, opt2, ... opt5], KeyField) - Save the transient stability option settings to an auxiliary file specified by FileName. Opt1 through Opt5 should be set to YES or NO according to the specific option categories to save. These parameters are optional and the default is YES for any parameter not specified. opt1 - Save Dynamic Models; opt2 - Save Stability Options; opt3 - Save Stability Events; opt4 - Save Results Settings; opt5 - Save Plot Definitions; KeyField – Optional parameter. Primary, Secondary, or Label. If not specified set to Primary by default.
• (January 28, 2011) TSCalculateSMIBEigenValues - Calculate single machine infinite bus eigenvalues. Initialization to the start time is always done before calculating eigenvalues.
• (January 28, 2011) TSSaveTwoBusEquivalent("PWBFileName",[BUS busnum]) - Save the two bus equivalent model of a specified bus to a PWB file. Initialization to the start time is always done before saving the two bus equivalent. “PWBFileName” – name of the PWB file to which to save. Bus can be specified by number [BUS busnum], name/nominal kV combination [BUS "busname_nominalKV"], or label [BUS "buslabel"]
• (January 28, 2011) TSLoadGE("FileName",GENCCYN) - Loads transient stability data stored in the GE DYD format. “FileName” – name of the DYD file to load. GENCCYN - YES or NO. Set to YES to split combined cycle units. Set to NO to leave them alone.
  (January 28, 2011) TSLoadBPA("FileName") - Loads transient stability data stored in the BPA format. “FIleName” – name of the BPA file to load
• (January 28, 2011) TSLoadPTI("FileName", "MCREfilename", "MTRLOfilename", "GNETfilename", "BASEGENfilename") - Loads transient stability data in the PTI format. “FileName” – name of the DYR file to load. This is NOT an optional field. All of the files listed after are optional. If not loading these particular files, specify an empty string, "".
• (February 4, 2011) Added error check on the summation of Kx inputs for the TGOV5 and WSIEG1 governor models.
• (February 4, 2011) For the Transient Limit Monitors, added the ability to filter using area/zone filters.
• (February 4, 2011) Added right-click option to create a two-bus equivalent to the generator state case information displays.
• (February 4, 2011) Added routines to initialize new machine models at a generator based on the existing active machine model at the generator.
• (February 4, 2011) Added ability to record the Interface "Limit %" and the Branch "Limit %" during a stability run.
• (February 4, 2011) Added auto limit correction for the REXSYS Vimax limit
• (February 15, 2011) When inserting a new machine model at a generator, add the ability to initialize the new generator model with parameters taken from an existing machine model of a different type.
• (February 15, 2011) Added newly named model for ESDC4B, ESST6B, ESST7B which are identical to the DC4B, ST6B, and ST7B models. Done to make names consistent with DYD file naming.
• (February 16, 2011) When storing a PWB file, the presently active contingency is now flagged so that when we re-open the PWB the PWB file this transient contingency is initialized as the active one.
• (February 22, 2011) Added full integration support for the ST7B and ESST7B exciters.
• (March 15, 2011) Added support for PSS3B stabilizer
• (March 24, 2011) Added exciter models BBSEX1, IVOEX, and EXIVO.
• (March 24, 2011) Added stabilizer models PSSSH and IVOST.
• (March 24, 2011) Added full support for HYPID governor model.
• (March 25, 2011) Added full support for generator relay models LHFRT and LHVRT
• (April 12, 2011) Added support for the coordination of the status of sections of a multi-section line in the transient stability simulation.
• (April 12, 2011) Added support for interface elements of type "multi-section line" when storing results of interface flows in the transient stability tool. Previously multi-section line elements of an interface were ignored.
• (April 20, 2011) Added full support for the WT4E wind turbine "exciter"
• (April 29, 2011) Fully implemented the WT4T model.
• (June 17, 2011) Added addition model validation for URST5T
• (July 7, 2011) Added ability to show line relays in the model summary display.
• (August 16, 2011) Added full support for the spdmult, UELin and Exclim paramters to ESDC1A and ESDC2A
• (August 16, 2011) Modified the EXST3 and IEEET1 exciters to add optional spdmult parameter to support the difference between these models in PSLF and PSSE
• (August 26, 2011) Created new ESST1A_GE model because PSLF handles input parameters related to the location of the PSS input and UEL input differently than PSSE.
• (August 26, 2011) Added default columns for present MW and Mvar to Load Characteristic and Load Relay model case information displays.

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User Interface Dialogs

• (June 25, 2010) Added ability to assign Case Comments to a case which designate a person's name and a time along with the comment. These are only stored in the PWB file format.
• (July 7, 2010) Added support for storing interface MW, Mvar, and MVA flows as part of the transient stability results.
• (July 7, 2010) Added ability to show the number of elements in a Transient Contingency.
• (July 7, 2010) Modified the Transient Contingency Element Dialog to show the filter information for choosing the object by default.
• (July 9, 2010) On the Present Topological Differences from Base Case dialog, the various case information displays of removed elements have been modified to provide a mechanism to right-click on a selection and choose to Save Selected to EPC file.
• (August 11, 2010) On the Auto-Insert Injection Groups Dialog, add an option to name an injection group by a specific name. This will only be used if only ONE injection group ends up being created based on the other options. The intent is to use this in conjunction with the new scrip command "InjectionGroupsAutoInsert;".
• (September 28, 2010) On the run mode dialogs for Branches, Generators, Loads and Switched Shunts, add indications of the Energized status of the device.
• (November 17, 2010) Added checks to prevent a dialog from becoming hidden behind the Windows Taskbar.
• (February 4, 2011) Added the losses to the branch Run Mode dialog. Also changed layout of flows.

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Bug Fixes:

• Auxiliary Files (SCRIPT and DATA Sections)
• Available Transfer Capability (ATC) Tool
• Bus View and Substation View Onelines
• Case Information Displays
• Contingency Analysis
• Distributed Computation
• Fault Analysis
• File Formats
• General
• Help
• Memory
• Integrated Topology Processing (ITP)
• Model Explorer
• Oneline Diagrams
• OPF Reserves Tool
• Optimal Power Flow (OPF)
• Power Flow Solution
• PV and QV Curve (PVQV) Tool
• Security Constrained OPF (SCOPF) Tool
• Sensitivity Calculations
• Simulator Automation Server (SimAuto)
• Time Step Simulation
• Transient Stability
• User Interface Dialogs

Top

Auxiliary Files (SCRIPT and DATA Sections)

• (July 23, 2010) Fixed access violation caused when calling MergeLineTerminals() with no branches actually meeting the filter. This will now simply do nothing instead.
• (October 28, 2010) Fixed error in using the SaveCase() command from a script file. Error was introduced in the patch on October 15.
• (December 10, 2010) Fixed an error in parsing the parameters of the OpenCase() script command choosing to open a PTI or GE file with options. The options specified would be ignored if there was a space between the comma and the bracket "[" which started the specification of the options.
• (December 28, 2010) Allow blank entries for custom expression variables. This is necessary so that when loading an auxiliary file that contains an existing custom expression the custom expression will end up being defined correctly if variables that previously existed should no longer exist.
• (December 28, 2010) Fixed editing of the switched shunt records for any of the special "EPC File" fields.
• (January 14, 2011) Fixed reading of auxiliary format export descriptions to clear existing Object Types when reading in replacement export descriptions.
• (January 25, 2011) When using the CaseDescriptionSet() script command to specify the case description, Simulator then sets the case description but includes the double quotes around the entire description. The double quotes are now removed.
• (January 25, 2011) Fixed bug with CTGWriteResultsAndOptions script that would not read the options correctly if there was an extra space before the bracket enclosing the options.
• (April 5, 2011) Modified to ensure that Area or Zone information is written using secondary key fields if requested. This affects Limit Monitoring Settings, Contingency Area Make-Up Power, and OPF options.
• (July 7, 2011) When loading in transmission lines or background lines using a display auxiliary file, the line vertices would not be read correctly if using regional computer settings that use a comma as a decimal symbol instead of a period. This has been fixed.

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Available Transfer Capability (ATC) Tool

• (August 24, 2010) Corrected loading in transfer limiters from an aux file when they are processed for only a single run and not for multiple scenarios.
• (September 3, 2010) Fixed an error that could occur when running an iterated ATC simulation that involved conditional contingency elements.
• (September 28, 2010) Modified some of the tolerances used when ramping the ATC transfer using injection groups when the injection group generators are hitting limits. This fixes a problem where manually increasing the transfer caused the transfer to exceed the desired amount.
• (October 1, 2010) When using the (IL) the Full CTG Solution method AND while using multiple ATC Scenarios, a bug was was introduced by recent speed enhancements. This has been fixed.
• (March 31, 2011) When running iterated ATC methods, the option to dynamically add slack buses as topology changes has been disabled. This means that any generation or load that is disconnected from the main island will become de-energized. This prevents incorrect results during the iterated portion of the process if a contingency causes generation or load to be islanded. This also mimics what is done using linear calculations for contingencies that island generation or load.
• (August 16, 2011) When using an injection group as a source in either the PV or ATC ramping and this injection group contained other injection groups with loads, it was possible that the appropriate transfer amount would not be implemented.
• (September 20, 2011) In the Distributed ATC process, added better error reporting and fixed the problem where post-contingency auxiliary files were not being sent to the remote processes.

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Bus View and Substation View Onelines

• (August 16, 2011) When showing the consolidated bus view in a full-topology model bus view, the font color of some fields was not obeying the default colors.

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Case Information Displays

• (September 28, 2010) When choosing to rename an advanced filter on the Filter Dialog, if the filter was referred to by another advanced filter the link would not be maintained after naming. This has been fixed.
• (November 17, 2010) Fixed the showing of the field names, column headers, and field descriptions of Custom Strings, Integers, Floats, and Expressions for case information displays showing a specific type branche record (Transmission Line, Transformer, Breaker, etc...). Previous the values would appear correctly, but the user-specified field or column names would not appear properly.
• (December 10, 2010) In versions of Simulator without the PVQV add-on, the ability to Toggle the Injection Group filed Scale? was not working. This has been fixed.
• (February 15, 2011) On the Area or Zone Tie-lines case information display, a tie-line representing a DC line was not properly showing the Far Bus' number and other information. This has been fixed.
• (February 28, 2011) When on the Area/Zone/Owner Filters dialog, modified the Save As > Auxiliary File option works. Previously it always wrote out the Area/Zone Number, Name and Shown Field. This was a problem because it may cause you to rename your areas or zones unknowingly. It will not prompt asking whether to write out using the Primary (Number) or Secondary (Name) key fields.
• (March 15, 2011) Fixed error with using a switched shunt filter on another object type as a "secondary filter".
• (April 20, 2011) Fixed error displaying min and max tap on the transformer bases for transformers with a fixed tap on the From bus
• (June 9, 2011) Fixed bug with using the filter toolbar and advanced filter dropdown. The dropdown would not allow you to select a filter.
• (August 16, 2011) Fixed an access violation that occurred when types were mismatched in a custom expression (like when trying to add a string and an integer together).
• (August 16, 2011) Fixed bug so that viewing the differences in column XF Auto for a branch can actually be shown when viewing the difference case.

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Contingency Analysis

• (July 7, 2010) Fixed bug that would prevent creating the following object types from an Auxiliary File or by copy/paste from a spreadsheet: ContingencyElement, CTGElementBlockElement, GlobalContingencyActionsElement, PostPowerFlowActionsElement.
• (August 11, 2010) Fixed a potential error that could occur if PostCheck contingency actions were used in combination with the "Solve Power Flow" contingency action.
• (August 11, 2010) When specifying a Post-Contingency AUX file which does not exist on your computer, Simulator is supposed to show a dialog telling you this and then abort the contingency simulation. This was not working properly and error was appearing saying "Cannot focus a disable or invisible window.". This error has been fixed.
• (August 30, 2010) Fixed potential access violation when using Advanced Limit Monitoring to look for voltage deviation violation in percentage instead of per unit.
• (October 28, 2010) Fixed errors that could occur when using Free-Floating Windows mode and opening or closing the contingency analysis dialog.
• (November 17, 2010) When using the contingency action to open a three-winding transformer, only the primary winding was being opened. This has been fixed.
• (December 10, 2010) Fixed error on What Actually Occurred? descriptions when using a SetTo or ChangeBy action for a Generator, Phase Shifter, or DC Line setpoint. The Contingency was always processed correctly, but the What Actually Occurred? string was incorrect.
• (March 24, 2011) A change implemented with the Feb. 15, 2011 patch caused the contingency analysis to run much slower. This has been fixed.
• (April 5, 2011) Fixed problem with linear contingency analysis that could cause incorrect results due to islanded generation or load not being accounted for. This also affects linear ATC analysis.
• (April 20, 2011) In the contingency solution where the line-drop compensation was used to change a generator to regulate its terminal, if the next contingency involved the closure of a line near a generator whose regulated bus was changed then the angle smoothing routine may cause the power flow solution to be pushed toward an incorrect (low voltage) solution. This has been fixed.
• (March 31, 2011) When using integrated topology processing, contingency blocks were not being included in determining which breakers should be preserved when using the option to preserve breakers. This could result in incorrect results because all breakers that needed to be opened were not available. This has been fixed.
• (August 16, 2011) When loading the PTI CON file entries for MOVE, entries were always being interpreted as SHUNT moves, so that GENERATOR and LOAD moves were not properly read. This has been fixed.
• (October 11, 2011) Display contingency violations correctly when using Integrated Topology Processing. Make sure that the metered flow end of a branch is shown as the actual bus instead of the pnode of that terminal while the case is consolidated.
• (January 25, 2012) 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.

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Distributed Computation

• (August 12, 2010) Continued stability improvements for the distributed computation add-ons.
• (August 30, 2010) Under some circumstances, distributed computation could freeze at the end of a distributed run (either contingency or ATC). This has been fixed.
• (November 17, 2010) When using distributed contingency analysis, the existing results were not properly cleared before running the analysis, and thus the results were the concatenantion of previous results with the new results. This has been fixed.
• (December 10, 2010) Fix for distributed computation if machines finished initializing *after* computation had already completed, an access violation would occur.

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Fault Analysis

• (June 25, 2010) Fixed error with the handling of out-of-service switched shunt when using the IEC-909 fault calculation.
• (October 28, 2010) When choosing to write out an AUX file describing all the fault analysis data, the transformer grounding configuration were not being written. A DATA section is now written with this information.

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File Formats

• (July 9, 2010) When saving any file, Simulator was prompting the user about adding a comment to the file. This will now only be done when saving to the most recent PWB file format.
• (July 16, 2010) When appending a case using a RAW or an EPC file, set the area and zone numbers for loads. Previously these were not updated when appending.
• (July 16, 2010) Fixed error that would occur if choosing to save out an EPC file and then hitting cancel.
• (July 23, 2010) Fixed potential error when reading an PTI *.seq file for sequence data. It was possible for the transformer zero sequence impedance to not properly read from this file.
• (August 4, 2010) When writing out the internal generator R and X values to a RAW file, an old limitation existed preventing values larger than 999. This limitation has been removed.
• (August 4, 2010) When loading text files, modified to treat TAB characters identically to SPACE characters.
• (August 4, 2010) When appending to a case (from an EPC, RAW, or PWB file) if the From and To designations of a branch are backwards in the appending file, then the designations will now be flipped as part of the appending processes.
• (August 11, 2010) When writing out the DC converters for a multi-terminal line to an EPC file, Simulator write out modes of 0, 4, or 5 if the multi-terminal DC line had only 2 converters (similar to what is done for the Two-Terminal DC lines). This was reported as causing problem when reading into GE, so we now will write only 1, 2, or 3 instead.
• (September 21, 2010) Fixed an error introduced in the last patch which caused problems when loading old PWB files and when loading in PTI RAW files. The load would abort while reading the switched shunt records.
• (October 15, 2010) Write out the Voltage Checking Limit Max and Voltage Checking Limit Min values to EPC files with the same values that were read in. It is OK for them to be zero. We had been adjusting the zero values to values based on the limit monitoring limits.
• (October 15, 2010) When using a script to open a case file with a particular version such as "PTI30", Simulator was always using the feature to automatically determine the file format version and was treating the version as "PTI" instead. This has been fixed so that a specific file type may be specified.
• (October 15, 2010) The routine to automatically determine the file version of a PTI RAW file would fail and cause an "invalid integer error" if a section was terminated by "0" or '0' instead of just the character 0. This has been modified to accomodate the quotes if they are there.
• (October 15, 2010) when writing out FACTS records to Version 30 we were writing a string "name" instead of the integer NUM for the first record. Similarly for Version 31 and 32 we were writing the number instead of the name. This has been fixed.
• (November 17, 2010) When appending using the RAW file format, three-winding transformers were always being created instead of modifying an existing record.
• (November 23, 2010) When loading the HDB Export CSV file format, the custom strings for ZBR records were not saving the Line ID.
• (December 10, 2010) When appending an EPC file, fixed a problem with creating a multi-section line where the existing line was not a multi-section line.
• (January 14, 2011) Fixed an out of bounds error that occurred when reading version 32 RAW files generated by Model on Demand that didn't contain some options on the title line that would normally be present. In the absence of these options, Simulator will generate defaults instead.
• (January 25, 2011) Fixed reading of the QTable from an EPC file.
• (January 25, 2011) When writing out area/zone information for branches to the EPC file, if the EPC extra data is not available, we now write the area/zone to which Simulator will assign the line losses (as determined by the metered end of the branch)
• (January 25, 2011) When loading the Areva hdbexport CSV file while Windows Localization settings were set to use a comma as the decimal separator, all values were read incorrectly. This has been fixed.
• (February 28, 2011) Fixed text when reading a GE EPC file for message regarding generators being set to "AVR = NO". Previously the number of generators changed was correct, but the number of affected buses was not.
• (March 15, 2011) Fixed problem with appending switched shunts to a case using a RAW file. Previously, the modified switched shunt records were flagged as "created" instead of "modified".
• (March 25, 2011) When writing out area/zone information for transformers to the EPC file, if the EPC extra data is not available, we now write the area/zone to which Simulator will assign the transformer losses (as determined by the metered end of the branch). This should have been included in the January 25 patch but was missed.
• (April 5, 2011) Fixed problem with reading in the limits for ZBRs from an Areva hdbexport CVS file.
• (April 5, 2011) Fixed a problem when writing to an EPC file so that generator setpoint voltages get reflected correctly in the scheduled voltages of the buses that they are regulating.
• (April 5, 2011) When writing to RAW and EPC files, account for generators that are on line drop/reactive current compensation by setting them to regulate their own terminal bus to the present voltage at the terminal bus.
• (April 29, 2011) For three-winding transformers with the tertiary winding omitted, the reading and writing of the internal star bus voltage and angle has been modified to be consistent with the treatment of these buses in the EPC file format.
• (April 29, 2011) Fixed bug with writing out the transformer grounding code for sequence data files.
• (June 30, 2011) Fixed a bug reading three winding transformers from PTI contingency file.
• (August 16, 2011) Fixed the handling of how aloss is used to determine the metered point on a multi-section line when reading in the EPC files.
• (August 16, 2011) Fixed loading of a PWB file to append information to a case to ensure that limitset information is read correctly for Buses, Branches and Interfaces.
• (August 16, 2011) Fixed loading of a PWB file to append information to a case to that duplicate Injection Groups, Interfaces, Nomograms, and Super Areas are not created.
• (August 16, 2011) Fixed error in Writing out switched shunts flagged as a Bus Shunt to the EPC file shunt records. If the switched shunt did not contain any blocks it would write out a nominal Mvar of zero.
• (August 26, 2011) An error could occur if appending a case that contains existing interfaces with a PWB file that also contains interfaces.
• (September 20, 2011) When reading an EPC file, better handle some object ID fields that might be blank that would have caused the file not to load correctly.
• (October 11, 2011) When writing line shunts to an EPC file, retain the original IDs it they contain an f or t. Also, maintain the EPC convention that the f and t indicate the end of the line that the shunt is on. If an ID does not contain an f or t, an appropriate unique ID will be created.
• (October 11, 2011) Fixed an access violation that could occur when loading an EPC file that contains three-winding transformers with no tertiary winding.
• (October 11, 2011) Fixed potential bug when loading a RAW file that contains comments. The comments were being included in the count of fields and this could result in an incorrect number of fields being read.
• (October 27, 2011) When loading in an hdbexport CSV file the owners were being determined incorrectly because we were indexing incorrectly.

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General

• (January 14, 2011) In certain instances a load could be double counted in the list of owners if its owner is the same as its terminal bus' owner.
• (March 15, 2011) Fixed GUI error when closing a branch in a dead island. Simulator was modifying the voltage magnitude to 1.0 even though the island was dead.
• (March 15, 2011) When using a remote desktop connection, it was possible for an error "A call to an OS function failed" to occur. This did not cause further trouble, but did require the user to dismiss a dialog.
• (April 29, 2011) Fixed bug that could occur when changing the area or zone of a generator, load, or switched shunt to be something other than the area or zone of its terminal bus. Zero would be reported for the area or zone instead of the correct area or zone.
• (March 31, 2011) Fixed bug that was preventing the special contingency options from being available (not grayed out) with Limit Monitoring Settings.
• (June 9, 2011) When copying the contents of a case information display to Excel, it was possible that some of the column headers would be missing. This has been fixed.
• (September 20, 2011) Fixed a crash that occurred upon close of the program when using hardware license keys.
• (October 11, 2011) Fixed access violation that could occur when creating calculated fields and using the filtering option to limit objects that are included in the operation.
• (October 11, 2011) Modified MoveLineRecord functionality to prevent parallel lines from having the same circuit ID.
• (October 27, 2011) Fixed error in Determine Shortest Path Between tool. The shortest path was being determined based on going across lines that should not have been allowed.
• (January 25, 2012) 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.

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Help

• (June 28, 2010) Added help files and block diagrams to the PowerWorld documents download page here.

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Memory

• None.

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Integrated Topology Processing (ITP)

• (September 10, 2010) Fixed a potential issue with restoring states when using consolidation related to a generator's regulated bus number.
• (November 23, 2010) After saving a case as a consolidated case, access violations could result if Calculated Fields existed. The case was saved correctly, but the the process of saving could corrupt the existing case in memory. This has been fixed.
• (December 28, 2010) Fixed an error with defaulting that Allow Consolidation field of all branched back to YES whenever a DATA section for the BRANCH object type was read from an AUX file
• (January 14, 2011) In some instances, the flows on consolidated branches weren't being calculated after deconsolidation. This has been fixed.
• (October 11, 2011) Fixed bug that would not pick the correct bus for the superbus pnode. As part of this fix, dead “ground” buses will not be picked as a pnode unless as a last resort.
• (October 11, 2011) Display contingency violations correctly when using Integrated Topology Processing. Make sure that the metered flow end of a branch is shown as the actual bus instead of the pnode of that terminal while the case is consolidated.
• (November 23, 2011) When saving the consolidated case using the check box option "Convert Shunts to Blocks", an access violation could occur causing the export to fail. This has been fixed.
• (December 21, 2011) Fixed access violation that could occur when saving a consolidated case to file and using the option to "Convert Shunts to Blocks".
• (January 6, 2012) Fixed a bug that could move devices from their original buses to their pnodes following consolidation and deconsolidation.
• (January 6, 2012) Fixed bug that could set switched shunt control mode incorrectly to Fixed if using topology processing along with another add-on that restores system state to the base case state after processing, i.e. contingency analysis, PV, QV, or ATC. This should have only occurred for shunts that were already located at their superbus pnode in the deconsolidated state. This was actually fixed in the November 23, 2011 patch, but the above bug was introduced by that fix. The fix incorporated here fixes both problems.

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Model Explorer

• (April 5, 2011) Fixed random access violations that could occur when using the Model Explorer.

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Oneline Diagrams

• (June 25, 2010) On the contour dialog, the choice of interpretation was not being saved properly to a PWD file. Thus when the diagram was reopened the choice was not retained. This has been fixed.
• (July 7, 2010) Fixed flashing hint windows caused by interaction between navigation arrows and oneline hints.
• (July 23, 2010) Fixed error with anchoring of transmission line objects after saving some oneline diagrams.
• (August 4, 2010) Changed the icon size for the end of transmission lines to be smaller when exporting to a KML file.
• (August 11, 2010) When switching to a Saved View which specified that no contour should be shown, the contour was not properly removed. This has been fixed.
• (September 3, 2010) 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.
• (September 10, 2010) Fixed a oneline "flicker" that could occur when using the line navigation arrows.
• (September 10, 2010) The 3D oneline options were not available when right-clicking on a oneline diagram in 3D mode. This has been fixed.
• (October 6, 2010) Fixed bug that would not allow custom fields to be correctly assigned with default drawing values for zones.
• (October 6, 2010) Fixed bug that would not allow any fields to be correctly assigned with default drawing values to multi-section lines.
• (December 1, 2010) When inserting a new transmission line on a oneline, an access violation occurred. This has been fixed. The error was introduced in the 11/23 patch.
• Fixed error on the Find Oneline Objects dialog when tyring to define a filter for the list of objects.
• (January 14, 2011) Fixed line-based display objects so that all vertices snap to the grid.
• (March 15, 2011) When creating PWFormOptions by reading an AXD file into an existing oneline, the new PWFormOptions object will be initialized with the settings present oneline.
• (April 12, 2011) When saving the Dynamic Formatting descriptions to an auxiliary file, associated advanced filters were saved previously. However, if those advanced filter referred to other advanced filters then the referred to filters were not included. This has been fixed.
• (April 29, 2011) Fixed bug that would cause the generator rotor symbol to not be set correctly when it was set upon initial insertion of the generator display object.
• (March 31, 2011) Fixed bug that would unlink an interface field from the appropriate interface when viewing the interface field dialog.
• (July 14, 2011) Modified Line Flow Object so that it can only be clicked on during edit mode so that the lines behind them can be properly clicked on in run mode.
• (October 27, 2011) When using the Actual Value (Weighted Average) and Actual Value (Only Closest) types of values when contouring, GPU acceleration will not be used so that the contour will be displayed as expected.
• (October 27, 2011) Fixed some artifact problems when using GPU acceleration with contouring.

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OPF Reserves Tool

• None.

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Optimal Power Flow (OPF)

• (January 25, 2011) Fixed error when solving a DC OPF in that we were not resolving the power flow after modifying a MW transaction control variable. The DC Power flow is needed here even in the DC OPF because we need to redispatch the generation in the non-OPF area.
• (February 15, 2011) Modified how OPF solution involving multiple islands with dispatchable MW Transaction and DC Lines is coordinated. The DC lines and MW Transactions are now coordinated to ensure that the inter-island DC lines flows are appropriately managed.
• (February 15, 2011) When using a dispatchable MW Transaction between two areas on OPF with the MW transaction price determined by the OPF, the post-OPF book-keeping for showing an Area's total cost including transaction costs was not handled appropriately. This has been fixed so that the Import and Export area have an appropriate exchange of money for the transaction exchanged.
• (March 24, 2011) Fixed a bug that could result if dispatching transactions in the OPF where the generation in the area not on OPF control would not be adjusted for the change in the transaction. This would only occur when using the DC OPF.
• (August 16, 2011) When using the DC approximation and running the OPF or SCOPF, fixed an internal tolerance error which could result in solution never completing.

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Power Flow Solution

• (June 25, 2010) Fixed error in handling of phase shifters in the DC approximation solution.
• (July 9, 2010) Fixed error caused when a MTDC Converter ended up with a current flow of exactly 0.0 amps. This resulted in a number being equal to 0/0 which resulted in a "NAN" result causing the power flow to fail.
• (August 4, 2010) When calculating the flow on a branch after solving a DC power flow, the contribution of MW Line Shunts was not properly handled. The actually DC power flow solution was correct, but the line flow would not be correct. This has been fixed.
• (August 24, 2010) Fixed improper handling of magnetizing conductance in some locations when using the DC power flow approximation.
• (September 3, 2010) Fixed a bug which could cause solution convergence difficulty when allowed discrete switched shunts to switch in the inner power flow loop.
• (September 10, 2010) 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.
• (September 10, 2010) 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.
• (September 10, 2010) 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.
• (September 21, 2010) Improved the performance of the angle smoothing routine when used to close in low impedance branches adjacent to a large number of other low impedance branches (such as in a full topology model).
• (September 27, 2010) Fixed access violation that could occur when an AC bus terminal of a multi-terminal DC line was outaged.
• (November 23, 2010) When using the feature on the MW Transactions table to choose to "Clear Transactions and Auto-Insert Tieline Transactions", if one of the multiterminal DC Converters was acting as a tie-line, then the resulting transaction totals were incorrect. This has been fixed.
• (January 25, 2011) When using the DC approximation, the flow on DC transmission lines was not being properly updated if the user changed the MW or Amp setpoint. This has been fixed.
• (February 15, 2011) Fixed potential floating point error when a failure occurs in the robust solution process.
• (February 15, 2011) When loading a power system model, additional code was added to ensure that generators regulated the same bus have the same setpoint.
• (March 15, 2011) Fixed error introduced in Feb 15 patch related to the coordination of the voltage setpoint by generators which have the same regulated bus. An error was introduced if you were modifying the regulated bus while at the same time modifying the voltage setpoint. Simulator would modify the other generators that had a common regulated bus even though the generator's regulated bus was just changed. This has been fixed.
• (March 24, 2011) Fixed remote regulation check done when verifying if a generator is able to remotely regulate its specified bus. If the regulated bus of a generator also has a generator that regulates a different bus, that bus is not allowed to be remotely regulated. Both the generator that is remotely regulating that bus and the generator at that bus will be turned off AVR.
• (April 5, 2011) Additional code was added to ensure that generators regulating the same bus have the same setpoint. This change enhances similar changes made in the Feb. 15, March 15, and March 24 patches.
• (April 12, 2011) An error in the power flow solution was introduced in the April 5 patch. The errors were related to how generator remote voltage regulation was configured when multiple generator regulated the same bus. The error would not cause an incorrect power flow solution, but would frequently cause no solution to be achieved.
• (March 31, 2011) Fixed bug associated with equivalencing lines that have the equivalent line ID and non-zero charging values.
• (March 31, 2011) Fixed some errors with custom expressions and custom model expressions to properly identify an expression as not being valid if all variables in the expression are not assigned to valid fields. A blank result for an expression means that the expression is not valid.
• (June 17, 2011) Fixed a rare error which could occur if multiple generators existed an island slack bus AND there was a mix of AGC=YES and AGC=NO settings for the generators, AND some generators had a non-zero minimum MW output. This could results in some generators in this grouping going UP while other went DOWN.
• (June 30, 2011) Fixed bug that would incorrectly dispatch MWs for island slack generators with negative minimum MW limits. This bug was introduced in the June 17, 2011 patch with the fix for the error related to dispatching multiple generators at the island slack bus if there was a mix of AGC settings.
• (July 14, 2011) When using the Scale feature to scale generation in an injection group, enforcing MW limits, and some generators hit limits, the full desired scale amount was not properly achieved. This has been fixed by allocating the portion of the scaling that cannot be accommodated by generators hitting limits to generators that have not yet hit limits.
• (July 14, 2011) When using the Scale feature to scale load in an injection group, maintaining a constant P/Q ratio, and scaling from the present value, the constant P/Q ratio was being applied to the injection group as a whole instead of individual loads. This has been fixed by scaling the Mvar load to maintain the same P/Q ratio at individual loads.
• (September 20, 2011) Properly check voltage regulation conflicts so that a generator that is not on AVR control will not cause a switched shunt or transformer that is regulating the same bus to be turned off control.
• (October 11, 2011) Fixed a bug that would not allow an island to become viable even though it contains load by checking the nominal load instead of actual load. The actual load might be zero in a dead island if also using the options for minimum per unit voltage for constant current and constant impedance load due to the voltage at the bus being zero.
• (January 25, 2012) 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.

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PV and QV Curve (PVQV) Tool

• (June 25, 2010) Removed irrelevant message dialog when saving QV results to an AUX file. This occurred for QV curves involving a contingency which could not be solved.
• (July 16, 2010) Added more error handling when saving the tracking results file in the QV curve. This should help prevent process failures when the file network location is unavailable.
• (July 23, 2010) Fixed problem with plotting base case values on the horizontal axis. Need to determine plot points based on a common nominal shift and can't assume that there will be the same number of points in a scenario and the base case results.
• (August 30, 2010) In the "New Plots" features if you have defined a value to contained in a plot it is automatically stored as part of the result while running the PV tool. However, when choosing to plot a bus dV/dQ value, the value was not being tracked properly with this new feature. This has been fixed.
• (September 3, 2010) Modified qvExtraMonitoring file so that the results can be easily identified by the contingency and bus which created the results.
• (October 1, 2010) When tracking a Voltage to Q injection, Voltage to Power Transfer, or PTDF sensitivities in the PV Curve tool it was possible that the calculations were being performed on an invalid Jacobian matrix resulting in incorrect tracking results. This has been fixed.
• (March 24, 2011) While in Free-Floating Windows mode the QV dialog could not be opened. This has been fixed.
• (May 5, 2011) Fixed error when loading PV results summary table from aux file on top of existin results (loading in fresh new results worked correctly). If the existing PV Scenario in results was critical, but the aux file contains the same scenario which was NOT critical, the results table would not load correctly.
• (August 16, 2011) When using an injection group as a source in either the PV or ATC ramping and this injection group contained other injection groups with loads, it was possible that the appropriate transfer amount would not be implemented.
• (September 20, 2011) Better handle the sink injection group hitting limits in the PV tool. Previously, the iterative process that attempts to get the slack change within tolerance and the sink as close to its limit as possible might cut off the transfer change at the wrong point, resulting in the sink not getting as close to its limit within the slack movement tolerance.

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Security Constrained OPF (SCOPF) Tool

• (April 5, 2011) Fixed problem with not being able to run more than one Outer Loop Iteration (contingency loop) during the AC SCOPF. The process would abort because it thought that there were no control changes during the first outer loop iteration.
• (November 23, 2011) Fixed a bug which could occur when loading a PWB file that had previously saved Tableua information in it. The maximum number of LP Iterations was then not properly updated and subsequent run of the SCOPF would execute as though the maximum iterations were 99.

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Sensitivity Calculations

• (August 4, 2010) Fixed bug in the LODF calculations introduced in the July 23 patch.
• (August 30, 2010) Fixed error in performing AC TLR sensitivities which was caused by a bug introduced in the speed enhancement from July 23, 2010
• (November 17, 2010) Modified default column on the Flows and Voltages dialog so that the list of LTCs includes the Voltage to Tap Sensitivity
• (January 28, 2011) The Sensitivity value for a branch's Mvar or MVA flow when the branch was connected to a PV bus was not being properly calculated. This has been fixed.
• (March 31, 2011) Fixed bug that would not allow matrix results for multiple direction PTDFs, matrix LODFs, and multiple TLRs to be returned from SimAuto functions.

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Simulator Automation Server (SimAuto)

• (October 28, 2010) Fixed error in using the SaveCase command. Error was introduced in the patch on October 15.
• (November 23, 2011) Fixed various GetParameters*() call when using the field format "variable:0:8:4" to specify that 8 digits and 4 decimal points should be returned. Previously it was always returning 12 digits and 6 decimals regardless of user specification. It will now use the specified amount if given, or default back to 12 and 6.

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Time Step Simulation

• (June 25, 2010) Fixed problem when pasting injection group data from Excel into time step simulation input.
• (July 2, 2010) Fixed bug with deleting columns from injection group inputs.
• (July 2, 2010) Fixed problem with scaling load with injection group inputs.
• (July 2, 2010) Fixed ability to defined load fields as part of result tracking.
• (August 4, 2010) Fixed bug with writing out injection group CSV files that would add the date and time to the file twice. This would also have affected the switched shunt CSV files.
• (August 4, 2010) Added scroll box around options on the Time Step Simulation dialog.
• (September 10, 2010) Fixed error with creating time step actions which change the generator voltage setpoint.
• (January 25, 2011) Fixed errors with applying schedule subscriptions when time points were left out of the schedule.
• (February 15, 2011) Modified the Schedule Subscription dialog to sort the object id list, field list, and schedule list alphabeticially.
• (February 15, 2011) Fixed error when showing the Schedule Subscription dialog when specifying a multiplier with a negative sign.
• (February 15, 2011) Added ability to use an advanced filter when showing the list of Schedules or the list of Schedule Subscriptions.
• (March 15, 2011) Fixed a problem with reading in a TSB from a newer patch release into an older patch release. It wouldn't filter out all of the custom result and custom input fields that don't exist in the older patch release.
• (April 20, 2011) Fixed some problems with plotting and displaying custom results for Owners, Zones, Loads, Transformers, and Super Areas.

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Transient Stability

• (June 25, 2010) Modified storage of Transient Contingencies to an AUX file to properly use number identifiers when appropriate.
• (June 25, 2010) Fixed error in initializing the SMIB calculation to properly handle a generator that was de-energized.
• (June 25, 2010) When storing data to Hard-Drive while using the Integrated Topology Processing, information is now stored using the full-topology bus number identifiers so that they can be properly read back in.
• (June 25, 2010) Fixed error in handling of Generic Limit Monitors looking at over frequency for synchronous generators.  The action to take was not being properly interpreted.
• (July 7, 2010) Fixed bug with writing TSR files. The bug was introduced in July 2 patch.
• (July 7, 2010) Some problems with access violations when running stability were encountered related to the plot designer. These should be fixed now.
• (July 7, 2010) When auto-correcting the Xl value for a GENSAL, GENROU, or other synchronous machine model, the informational message had a typo indicating it was changing Xqp. This typo has been fixed.
• (July 7, 2010) The auto-correction routine was not allowing the Linc value of a GAST_GE model to be near zero. This restriction has been removed.
• (July 23, 2010) Fixed error when plotting either 7 or 10 subplots on a single plot. The subplots were not laid out properly.
• (August 4, 2010) Fixed a bug where trying to show a plot at the execution of transient stability. The plots were shown but never properly refreshed.
• (August 4, 2010) Modified so that the generator internal R and X values are always updated to match the generator subtransient or transient impedances as appropriate. This is done when the stability is either solved or when the stability data is loaded or stored. These fields must match and the stability data exported to other software must reflect the fact that Simulator always uses the data specified with machine models.
• (August 4, 2010) Fixed a bug in how the saturation of GENROU and GENSAE models was handled.
• (August 11, 2010) Modified to better handle the saturation of the GENTPF and GENTPJ generator models
• (August 24, 2010) Fixed an incorrect choice in the choices appear in the Toggle Drop-Down for generator objects's Governor Response Limits.
• (August 24, 2010) Fixed typo for the column heading which mixed up the K1 and K2 parameters for the IEE2ST stabilizer.
• (August 24, 2010) Fixed the running of multiple transient contingencies to obey the SKIP field of a transient contingency. Previously we were always running all the transient contingencies. It will now skip them as specified.
• (August 24, 2010) For some generators there were hard limits on the value of H, D, Tdo, Tdop, and the Saturation values. These limits previously were auto-corrected but have been changed to leave the values and only create a warning.
• (September 3, 2010) Fixed problem with the default numeric format used for showing axis label values.
• (September 3, 2010) 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.
• (September 3, 2010) Fixed error in initialization of REX exciter model when Xc <> 0.
• (September 13, 2010) 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 14, 2010) Fixed error in induction motor saturation modeling introduced in September 13 patch.
• (September 21, 2010) Fixed an error with reading the WT3E model from a DYD file.
• (September 21, 2010) Improved the accuracy of the initialization of the slip for induction motor load models (such as CIM5, CIM6, MOTORW). This helps ensure that everything initialize to exactly zero derivatives. Previously they were very close. Now they are nearly exactly at zero derivative.
• (September 21, 2010) Fixed an error in the initialization of the ST6B (also known as ESST6B) exciter when the Km <> 0.
• (September 22, 2010) Fixed initialization of the EXWTGE exciter if Kiv = 0.
• (September 22, 2010) Decreased tolerances for initialization of the WNDTGE pitch angle/wind speed to reduce initial mismatches.
• (September 22, 2010) Increased tolerance for what is considered "zero" when initializing the HYGOV, HYGOV4, HYG3, and WEHGOV hydro governor models. These can be problematic for a generator operating at 0.0 MW output because the equation H = sqr(Q/Qss) becomes ill-defined if Q = 0 and Qss = 0 as occurs in initialization of a generator operating at 0.0 MW output.
• (September 27, 2010) Fixed error in determining whether islands have been created related. If a branch was only open at one end it still can create an island and this was not properly accounted for.
• (September 28, 2010) Further modifications to the HYGOV, HYGOV4, HYG3, and WEHGOV hydro governor models to avoid problematic 0/0 situation when initializing a generator operating at 0.0 MW output.
• (October 1, 2010) Fixed some GUI interaction issues with the transient stability dialog related to the Manual Control the the run.
• (October 6, 2010) The fields ROpen and RClose with the GGOV governors were not being used. This has been fixed.
• (October 6, 2010) Modified the transient contingency elements for branches for "Open From End" to "Open To End" to instead be "Open Near End" and "Open Far End" to be consistent with defining the contingency.
• (October 6, 2010) Added additional Sub-interval integration support in situations where the IEEEST has A1 or A3 values which are too small resulting in numeric stability trouble.
• (October 15, 2010) Modified the WEHGOV, HYGOV, HYGOV4, and HYG3 governors so that the turbine flow (q) can not become negative.
• (October 15, 2010) Fixed bug in which state Id/Iq curents were not getting updated correctly for GenSal model when using subintervals. This bug would show up when the fault is close to the generator.
• (October 15, 2010) Fixed error in Type 4 wind turbines which require ignoring Xpp.
• (October 28, 2010) Fixed error in the handling of circuit parameters for the WT2G model.
• (October 28, 2010) Fixed a bug when using the EXWTGE exciter model for some values of fVarFlg.
• (November 23, 2010) Fixed a bug when writing out a GE DYD file which contained a PIDGOV governor. If one of these governors existed, then writing out the DYD file would cause the program to halt.
• (December 1, 2010) Fixed minor bug in the REXSYS exciter
• (December 28, 2010) When loading a PTI DYR file which contains GENCLS models, the Ra and Xdp values were not being automatically set to internal impedance values. This has been fixed.
• (December 28, 2010) Modified to prevent the network equation convergence tolerance from being set to a value smaller than 1E-5.
• (December 28, 2010) Fixed bug with CIM models in which they were not being autocorrected if Xl > Xpp
• (December 28, 2010) Removed limit check for generator impedance values since these values can differ substantially when MVA base for generator is set to the power flow base, as is common in older cases.
• (January 14, 2011) When reading a DYD file and choosing to split generators represented by GENCC machines, a bug was introduced in the December 10, 2010 patch which caused both generators to have the same Generator ID. This has been fixed.
• (January 14, 2011) Fixed Show Dialog... right-click menu option in the Validation listing to properly show the Generator dialog.
• (January 25, 2011) Fixed error with writing out the WT4E1 model to a DYR file. The last 3 parameters were omitted and 3 integer parameters were written out as floating point numbers.
• (January 25, 2011) Fixed error when switching between different dynamic models on the generator dialog. The number of decimal points shown for various values on the dialog were not always being updated appropriately.
• (January 28, 2011) Fixed an error when reading the MCRE field with how omitted fields are treated in the MCRE file.
• (February 4, 2011) Fixed error with assigning an owner when reading the MTRLD helper file in splitting up loads when reading a DYR file with options.
• (February 4, 2011) When showing the Bus Voltage maximum decrease or increase, the values were backwards. This has been fixed.
• (February 4, 2011) Fixed errors in the modeling of faulted branches which are only closed at one end.
• (February 4, 2011) Fixed error in handling of scaling of low pressure values in the WSIEG1 model
• (February 15, 2011) When loading in an AUX file containing plot definitions, the Plot Designer was updated to list this new definitions until the Transient Stability dialog was closed and reopened. This is now properly updated immediately.
• (February 15, 2011) Fixed bad behavior of the Transient Stability Plot Designer when running in Free-Floating Windows mode.
• (February 16, 2011) Handled potential problem with very small Ta values in the EXBAS exciters when there is feedback to prevent numerical instability.
• (February 16, 2011) Fixed initial limit violation handling of Vfemax in the EX2000 exciter.
• (February 16, 2011) Fixed access violation that could occur when using the CLOD load model.
• (February 22, 2011) Added proper implementation of the fVltFlg=1 for the WT3E1 wind turbine electrical controls
• (March 31, 2011) Prevent user from closing Transient Stability dialog while the analysis is running.
• (June 17, 2011) Fixed error with loading the Transient Limit Monitor's advanced filter from a PWB file. The filter was not properly maintained.
• (June 17, 2011) Fixed error in initialization of the BBSEX1 and EXBBC exciters.
• (June 17, 2011) Fixed error in transient simulation when a DC line had Status=CLOSED, but was also BLOCKED.
• (June 17, 2011) Fixed bug in MAXEX1 and MAXEX2 models
• (June 17, 2011) Modified the implementation of SVC models so that any step-up transformer associated with the generator model is ignored if their is an SVC model.
• (August 16, 2011) For GPWSCC, the order of the parameters Kp and Kd were reversed. This has been fixed.
• (August 16, 2011) Fixed error in REXS to multiply it's output by Efd
• (August 16, 2011) Fixed error in saving a two-bus equivalent at buses which contained multiple generators.
• (August 26, 2011) Fixed error in stabilizers PSSSB, PSS2A, and PSS2B when n=0. This now means the ramp tracking is completely bypassed. Previously setting n=0 was causing simulator to disable the stabilizer completely which was incorrect.
• (December 21, 2011) Replace double quotes in the invocation section (identifier before the colon) of a GE DYD file with single quotes to handle bad file formats.

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User Interface Dialogs

• (June 25, 2010) Fixed multi-section line dialog bug. The Find From Bus button did not work when inserting a new MS Line.
• (July 9, 2010) Fixed error in feature to remove additional GE EPC data from the case.
• (August 11, 2010) Removed old options to "automatically open overheated lines during simulation".
• (September 13, 2010) 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.
• (October 6, 2010) Fixed bug that could cause the Model Conditions dialog to not be properly configured when opening the dialog for a particular Model Condition.
• (December 10, 2010) When creating an equivalent, if any terminal of a three-winding transformer was chosen to be in the External System, then all the terminal buses and the star bus would be flagged as in the external system. This has been modified so that only the star bus is automatically flagged as in the external system.
• (December 10, 2010) Modified the processing of what is considered a radial branch when choose to Remove Radial Systems on the Equivalencing Dialog. Previously the entire three-winding transformer would be equivalenced even if only the tertiary winding ended up begin connected radially.
• (December 10, 2010) On the Calculated Field Dialog an access violation occurred when choose to set the condition the Same as a Filter. This has been fixed.
• (January 5, 2011) Fixed various bugs with manually creating a multi-terminal DC line from scratch.
• (January 25, 2011) When using the merge buses feature, the newly merged bus must have its angle set based on the old buses to prevent a badly conditioned initial voltage estimate.
• (February 15, 2011) When using the user-interface to apply an advanced filter to a oneline display object (such as on the Select By Critera or Export KML file dialogs), an access violation could occur. This has been fixed.
• (March 15, 2011) On the multi-section line dialog, modified the Find dialog which appears when searching for the from bus of a new multi-section line so that is allows sorting by name, number or label.
• (April 12, 2011) Fixed incorrect value displayed in the Power Flow List for mismatch at buses with generators.
• (July 14, 2011) Fixed bug that would not allow you to copy from or paste into the Renumber Areas/Zones/Substations dialog.
• (December 21, 2011) On the Branch Information dialog, fixed a bug reporting the fault currents of the TO end B and C phases in amps. They were being converted to amps on the wrong nominal kV base.
• (January 25, 2012) Increased the number of decimal places shown from 1 to 3 for the reactive capability curve points on the generator dialog.

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