What's in the Simulator 14 Patch?

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

March 16, 2009

New Features

• Oneline Diagrams: Greatly enhanced the speed of using the "Send to Back" and "Bring to Front" features of a large selection of displays object.
• PV Curve Tool: Moved the option for setting the number of critical scenarios to find from the Results tab to the Common Options tab. It makes more sense here.

Bug Fixes

• Contingency Analysis: Fixed access violation that could occur when pasting or loading an AUX file with unlinked elements for monitoring by exception.
• Memory: When deleting a multi-terminal DC line record (whether manually, through a script, or through equivalencing), a memory access violation was occurring which corrupted the case. This has been fixed.

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March 17, 2009

New Features

• Contingency Analysis: Added support for reading/writing the global contingency actions using the objecttype GlobalContingencyActionsElement.
• Oneline Diagrams: Added a substation shape option to the default drawing values.

Bug Fixes

• File Formats: Fixed an error with closing a PWB file if it contained a switched shunt record that had originally been read from the FACTS Device section of a PTI RAW file.  This most commonly occurred with ERCOT cases at bus 9025.
• Contingency Analysis: When opening the contingency analysis dialog a dialog appears asking you whether you would like to set the present case as the contingency reference state. Regardless of what options were chosen on this dialog, Simulator was not setting the reference and the user would need to manually choose "Set as Reference" from the the Other button drop-down. This has been fixed.

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March 23, 2009

New Features

• Power Flow Solution: Changed the requirements for a viable island. Previously a 0 MW closed load was sufficient, but now islands must have closed load which is non-zero.
• Contingency Analysis: Added the ability to choose whether to include contingency options when saving contingency information to an Auxiliary File.
• Integrated Topology Processing: When using the Consolidated Superbus View with the Integrated Topology Processing add-in, we now force the showing of circuit breaker symbols on branches, loads, generators, and switched shunts which are Open.
• Integrated Topology Processing: Added support for using Bus, Generator, Load, Switched Shunt, Area, and Zone filters on a Superbus or Subnet.

Bug Fixes

• Contingency Analysis: When using the DC approximation (the DC Power Flow) with contingency analysis, the advanced contingency monitoring options were not being used. They are now included.
• Memory: A possible error could occur when opening the Model Explorer. This only occurred if a new PWB file had been opened after creating User Defined Case information Display. This has been fixed.

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April 8, 2009

New Features

• Available Transfer Capability: When using the ATC method "Iterated Linear Step with Full CTG", added a check to ensure that the Post-Contingency Auxiliary File exists.
• Available Transfer Capability: The ATC Dialog now allows you to open and still interact with other parts of Simulator. Care must be taken while actually running the ATC solution however now.
• Bus View Oneline: Added ability when customizing the bus view to specify the Delta Per Mouse Click with fields so that the up/down arrow spinners are drawn appropriately.
• Case Information Displays: Modified to return a better error message to the user when a Custom Expression has a circular reference
• Case Information Displays: Made the branch fields for "Branch Device Type" and "Consolidate Branch" available regardless of whether the ITP add-on has been purchased
• Case Information Displays: Added fields to show the "Number of" Breakers, Disconnects, and ZBRs in an Area, Zone, or Substation.
• File Format: When reading the GE and PTI files, the three-winding transformer magnetizing B and G values are now properly read into the three-winding transformer record. The two-winding equivalents were always properly created, this was only an issue with the three-winding data viewing.
• General: Added a new Tool to browse the Case Description headers for all the PWB files in a single directory.
• Integrated Topology Processing: In some full-topology models, buses are modeled which has no load, no generation, no shunt, and have only one branch connected to them which is always out-of-service. These buses represent ground points. The Integrated Topology Processing has been modified to better integrate these into the solution without creating a large number of dead buses unnecessarily.
• Integrated Topology Processing: Fixed several issues in the Bus View when showing the "Consolidated Bus View" when parallel connections exist between super buses.
• Oneline Diagrams: Line Navigation Arrows are now drawn on top of all other objects such as pie charts or circuit breakers.
• Oneline Diagrams: Changed the shape of the Line Flow Objects to match the shape of the animated flow arrows. An arrow shape is now used instead of a triangle.
• PV and QV Curve Tools: Added a check when running the PV Curve or the QV Curve tools to ensure that the Post-Contingency Auxiliary File exists. If the file is specified in the contingency analysis options but does not exist then the PV and QV curve will be aborted.
• PV and QV Curve Tools: When writing out PV Results, we now write out 5 decimal points intsead of 4.
• User Interface Dialog: Added the ability to specify the Magnetizing B and G values on the transformer base on the Transformer Base Dialog.
• User Interface Dialog: When right-clicking on a three-winding transformer dialog in Run Mode and choosing show dialog, we now open the dialog related to the three-winding transformer data.
• User Interface Dialog: Added storage to the windows registry regarding the choice of "Sort by Number" or "Sort by Name" on the various object chooser dialogs. This will now be remembered between sessions.

Bug Fixes

• Auxiliary Files: Added support for saving schedule subscriptions to aux files
• Auxiliary Files: When loading a case using the Auxiliary File, previously we would always recalculate the Line MW/Mvar flows after completing the load of the file. This has been modified so that if Line MW or Mvar values are read from the AUX file, then we do NOT recalculate them.
• Auxiliary Files: If transformer impedance correction tables were created using an auxiliary file after the transformers which used the tables were already created, then the link between the transformer and its table was not properly created. This has been fixed so that the order of creation does not matter.
• Case Information Displays: For interface elements and participation points of injection groups, the "Selected?" field was not working properly. This field now properly only returns the selected field of the underlying object (generator, branch, etc...) to which the element refers.
• Contingency Analysis: Fixed errors with modeling Bus Outages which create islanded load and generation using the Linearized Contingency Analysis methods.
• Model Explorer: Fixed some errors with how the User Defined Case Information displays were managed after you opened a different case.
• Oneline Diagrams: When drawing three-winding transformer objects, removed the drawing of a background color underneath the symbol.
• Oneline Diagrams: On the Pan/Zoom dialog, the checkbox for "Allow auto updating on selection" was not visible by default. It is now.
• Oneline Diagrams: When using the thumbnail view, the Line Navigation Arrows were not working properly. This has been fixed.
• Oneline Diagrams: On old video cards which do not support OpenGL, the new faster contouring algorithm was causing an error which caused Simulator fail. This has been fixed to just default to the older contouring routine.
• Oneline Diagrams: Switching to the 3D view on older video cards which do not support OpenGL could cause Simulator to fail. This is now captured and the switch to 3D is not allowed while an appropriate error message is shown.
• Time Step Simulation: When editing data directly in the case information display for time point load, generation, etc... values, after hitting the ENTER key the values were not be applied. This has been fixed.
• User Interface Dialogs: Modified the equations on the dialog for specifying transformer impedances on the transformer base. The shunt terms are not effected by the fixed taps or nominal kV values.
• User Interface Dialogs: When opening dialogs as maximized, the new feature in Simulator 14 which stores the location and size of dialogs was still being applied. For a maximized form this should not occur and has been fixed.

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April 9, 2009

New Features

• General: Added the ability to store in the Windows Registry whether the Ribbon is minimized and whether the Quick Access Toolbar is above or below the Ribbon.  This will then be remembered the next time you open Simulator.

Bug Fixes

• Case Information Displays: The drop-down button on Case Information toolbar which shows a list of available filters was broken in the patch released yesterday.  This has been fixed. This only effected that button and access to filters via right-click or the Filterbar was unaffected.

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April 10, 2009

New Features

• Power Flow Solution: Improved transformer tap switching coordination in situations were a large number (> 50) transformers are trying to switch and a large number of those are stuck at the minimum or maximum tap or phase.

Bug Fixes

• File Formats: Fixed an error which would cause the inability to read in a PWB file written using the April 9 patch. Note that any files for which you are seeing an error load the PWB file are NOT actually broken.  The error was only in the LOADING of PWB files and this is now fixed in the April 10 patch.

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April 14, 2009

New Features

• Auxiliary File Formats: When loading an auxiliary file format, if branch statuses are changed to close in a set of dead buses Simulator automatically makes a reasonable initial voltage guess for the newly energized buses. While most of the time this is helpful, if the AUX file also contained voltage phasor values for the buses, then the Simulator would override these values with our own estimate. This has been changed so that any bus for which the AUX file sets either voltage magnitude or angle will not have its voltage changed by our estimation routine.
• Contingency Analysis: Adding back in the old "Legacy Tables" options for sending contingency violations and contingency definition data to Excel. This was available in earlier versions of Simulator but had recently been removed.
• File Formats: Previously when loading an EPC file, only buses that had some online generation would set generator's AVR=NO in Simulator. This has been changed so that if there is no online generation, then the Mvar range for all offline generators is queried and all generators are set to AVR if the Mvar range is too small.
• Integrated Topology Processing: After loading in an AUX file, Simulator automatically calculates branch line MW and Mvar flows for all lines in the case. This has been modified so that if a branch has its flow values specified in the AUX file then the values are not left at the values read from the AUX file.

Bug Fixes

• Oneline Diagram: When adding an interface field to a oneline diagram on which no interface display objects are drawn a nuisance access violation would occur. This has been fixed.

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April 28, 2009

New Features

• Case Information Displays: Modified the field descriptions for specific types of interface elements, participation points, or transfer limiters so that the list of fields puts fields inside folder to make it clearer where the fields come from.
• Contingency Analysis: Added new option to the pop up menu for contingency records to Join Active Contingencies. This will create new contingencies that are the join of the current contingency list and a list read in from an auxiliary file. Only those contingencies not listed as being Skipped will be considered in the join.
• Integrated Topology Processing: When running the PV Curve tool modified to not store system states when using the topology processing.
• Integrated Topology Processing: General Improvement in the Bus View showing the Consolidated Superbus.
• Model Explorer: Modified the Filter Bar so that when you choose Find it automatically defaults the Filter By setting on the Filter Dialog to be the same as the Filter By choice on the Filter Bar.

Bug Fixes

• Available Transfer Capability: When using the iterated steps in ATC and ramping of the base case state, if the power flow fails the step size is reduced by a factor of 2. After a successful solution the entire remaining desired step was attempted immediately. This has been changed so that the decreased step size is used instead until the desired step is achieve or the minimum step size is reached. This should speed up the ramping in bad situations.
• Contingency Analysis: Fixed nuisance access violation that occured on the Lines/Buses/Tranformers tab of the contingency analysis form when toggling the Selected or Skip field on the list of related contingency violations for each branch, interface or bus.
• Oneline Diagrams: Added the right-click option to open the Area Information dialog from the oneline diagram.
• Power Flow Solution: Fixed more minor errors related to ensuring that transformer taps do not get stuck at their limits.
• Sensitivity Tools: Fixed the "Set Sensitivities of out-of-service buses to nearest" button so that it properly refreshes the results grid after being clicked
• Time Step Simulation: Corrected bug that prevented some transformer fields to be shown in the subscription field list
• User Interface Dialogs: Modifed the scaling of loads to ensure that generators do not also scale if the generator scaling is set to 1.000. Previously if you were enforcing generator MW limits in the scaling, Simulator would automatically bring generator up/down to their limits and then scale other generators appropriately so the net generation change was zero.
• User Interface Dialogs: Modified the Browse Folder Dialog to use the newer Vista style of browse folder dialog if available. This includes a place to paste a path in as well.

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May 1, 2009

New Features

• Contingency Analysis: Greatly enhanced the user interface for looking at "What Actually Occurred" in the contingency analysis results. When choosing this entry from the Combined Tables dropdown, you now see a list of what actually occurred under every contingency. There are also separate columns to query.
• Time Step Simulation: Add the ability to specify the default TSB file without a directory. This makes it possible to just look in the current working directory for the TSB. Also fixed the Excel save options to work accordingly

Bug Fixes

• Auxiliary File: Fixed error that could occur when looking up a Transformer object that did not exist.
• File Formats: When loading in an EPC file, when Simulator encountered any status values that were not appropriate no error message was generated and the device behaved incorrectly. This was first noticed with a case that had a branch status of -4. To correct this, and status which is not 0, 1, (or 2 for branches) will always be treated as closed and a log message will appear stating this.
• File Formats: When reading a RAW file, modified to assume a status of CLOSED for any entry in a RAW file with a status that is not 0 or 1.
• Power Flow Solution: When all DC converters in a multi-terminal DC line had power or current setpoints of zero, Simulator would generate a log message saying there were no rectifiers or inverters found. The solution was fine but the log message was confusing and has been removed.

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May 6, 2009

New Features

• Contingency Analysis: Added a new contingency element action type called "Open Breakers". When coupled with the ability to specify a branch as "Branch Device Type = Breaker", Simulator will dynamically determine a set of breakers to open either a Branch, Generator, Load, Switched Shunt, DC Line, Interface, Injection Group, or Three-Winding Transformer.
• Contingency Analysis: Added option with individual contingenc records to ignore contingency specific solution options. This is intended mostly to ignore the options that are specified for all contingencies, but any solution options set for the specific contingency will also be ignored.
• Fault Analysis: Changed default transformer configuration for fault analysis to ungrounded wye-wye instead of grounded wye-wye
• Integrated Topology Processing: Added a new contingency element action type called "Open Breakers". When coupled with the ability to specify a branch as "Branch Device Type = Breaker", Simulator will dynamically determine a set of breakers to open either a Branch, Generator, Load, Switched Shunt, DC Line, Interface, Injection Group, or Three-Winding Transformer.
• Oneline Diagrams: Added the ability to specify a "Delta per Mouse Click" for the area field showing the flow to another area. Modifying this value will modify the MW Transaction between the two areas.
• Power Flow Solution: Modified so that generators set to any kind of Wind Power Control Mode will not be automatically chosen as a slack bus when Simulator dynamically chooses a slack bus.

Bug Fixes

• Contingency Analysis: When showing the "Present Value" for Interface MW Violations in contingency analysis, the values were displayed in per unit. This has been changed so values are displayed in MW instead.
• Power Flow Solution: Modified so that generators at a slack bus that are also flags on a Wind Power Control Mode will properly behave as slack buses. Generally this should not be done, but Simulator will not at least handle this situation.

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May 20, 2009

New Features

• Case Information Displays: On the Area or Zone Tie-line displays, modified the type column to show the Branch Device Type for branches tie-lines.
• File Formats: When reading RAW files, added additional error trapping when encountering a two character circuit or device identifier string which contained a single quote. The RAW file would contain the text [1,2,'2'',...] which does not conform with a CSV file that uses a single quote as a string encloser. To fix this, Simulator now looks for a string of text of the form '*'' and handles it appropriately.
• Integrated Topology Processing: Added support to the OPF and SCOPF add-ons to utilize the ITP features.

Bug Fixes

• Available Transfer Capability: Modified to prevent the ATC calculation from occurring when using iterated methods for a transfer between areas if one of the area's AGC is set to not on area control. An appropriate error message is shown asking the user to adjust the control method before continuing.
• Bus View Oneline: Custom views with spaces in the name could not be selected from the Views drop-down. This has been fixed.
• Contingency Analysis: Fixed "can't make visible form modal" error when showing the make up power dialog for a particular contingency element.
• Integrated Topology Processing: Buses which have no generation, load, or shunts connected to the system through a single open branch are treated as part of the Superbus of the bus to which they are connected. This greatly reduced the number of Superbuses in systems that model earth grounding disconnectors. This patch prevents these disconnected buses from being chosen as the primary bus of the superbus which resulted in solution problems.
• PV Curve Tool: The PV Curve dialog did not properly maximize. This has been fixed.
• Security Contrained OPF: Fixed an error in the sensitivity calculations for generators connected to the system through parallel radial lines if a contingency was defined which outaged ONE of the lines. The generators were being treated as having zero sensitivity on the branch which remained in sensitivity and thus the overload could not be removed. This has been fixed.
• Time Step Simulation: Modified the export of schedules to AUX files so the decimal points are not fixed to 4.
• User Interface Dialogs: Fixed "out of memory" error caused when trying to scale by bus and scaling generation as well as load.

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May 27, 2009

New Features

• Auxiliary Files: When loading from an AUX file (or pasting from a spreadsheet), the ability to create transient stability data linked to power system records using the power system record labels as identifiers has been added.
• Auxiliary Files: When loading from an AXD file (or pasting from a spreadsheet), the ability to create oneline display objects linked to power system records using the power system record labels as identifiers has been added.
• File Formats: Fixed the reading of MW Transactions tables from the EPC file format. These transactions were not being brought in from the EPC format.
• File Formats: Updating the reading of interface records from the "NERC Book of Flowgates" to support 12 character bus names and three-winding transformer elements.

Bug Fixes

• Case Information Displays: The short-cut keys on case information displays did not always activate as appropriate. This has been fixed. This effected the Ctrl+F (find), Ctrl+C (copy selection), and Ctrl+V (paste) shortcuts.
• Contingency Analysis: The numeric fields shown for contingency records did not work properly when using the a custom expression. This has been fixed.
• PV Curve Tool: Before starting the PV analysis, make sure that the directory to which the output file should be written exists. If the output file should be saved. If the directory does not exist, it will be created. If for some reason it cannot be created, the PV analysis will not run.

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June 4, 2009

New Features

• None.

Bug Fixes

• File Formats: Added the ability to Read and Write generator capability files in the PTI GCAP format.
• Oneline Diagrams: Added ability for the user to specify which objects to export to the KML file as well as which data fields.
• User Interface Dialogs: Added a new feature to "Find Circulating Mvar and MW Flows" which will determine all the places in the power system model which have circulating flows. This is available under the Connections Menu on the Tools Ribbon tab.

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June 18, 2009

New Features

• Auxiliary Files Script Commands: Added support for moving Switched Shunt records to the Move() script command.
• Auxiliary Files Script Commands: Added a new RenumberMSLineDummyBuses("filename") script command which loads in a file with the new dummy bus numbers and new dummy names and makes changes. This new feature provides script acction to the option found with the multi-section line case information display.
• Contingency Analysis: When looking at a list of contingency violations in a case information display and choosing Show Dialog, the dialog of the violated element (Branch, Bus, or Interface) is now shown.
• PV Curve Tool: Added the ability to specify that the PV Curve output file be written as the transpose. Previously each row of text represented a transfer level and columns were tracked values. When choosing the transpose, each row represents a tracked value and columns represent the transfer levels.
• User Interface Dialogs: Added a severity ranking to the new circulating Mvar and MW flows tool to rank cycles according to an estimate of how much Mvar or MW loss the cycle is creating..

Bug Fixes

• Memory: Fixed a rare access violation that sometimes occurs when opening or closing a case.
• PV Curve Tool: Fixed potential error that could be encountered when doing the reverse PV transfer. This was caused by improper coordination of tolerance levels.

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June 25, 2009

New Features

• Auxiliary Files: Added an optional third parameter to the MOVE() script command to specify what percentage of the object to move. This is only valid for generator or load moves.
• Case Information Displays: Added support for the Selected and Custom Expression fields for the GenVarLim (generator Mvar limit) records.
• Power Flow Solution: When re-energizing an island by closing in a branch that connects the island to another energized island, Simulator estimates new voltages in the newly energized island before the power flow solution. A similar estimate has been added when energizing an island only by turning on generation in that island.
• SimAuto: Added support for accessing the SCOPF contingency violations using SimAuto and Auxiliary File script commands

Bug Fixes

• File Formats: Fixed error in reading in the load records of RAW version 31 files.

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June 30, 2009

New Features

• Auxiliary Files: Modified the SetData() script command to accept a filter name of "ALL" which means to apply this to all the objects.
• Auxiliary Files: Modified the PartPoint objects so they have access to the Selected Field and Custom Expressions of both the PartPoint object AND the related object (such as a load or gen)
• Auxiliary Files: Modified the Move() script command to better support moving a percentage of a load or generator to another bus.
• Power Flow Solution: Added the ability for transformers to use line drop compensation to regulate a point an impedance away from the regulated bus of the transformer.

Bug Fixes

• None.

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July 2, 2009

New Features

• Auxiliary Files: It was not possible to apply the area/zone filters to the InterfaceElement lists. This has now been enabled.
• SimAuto: Added the ability to obtain the SCOPF Contingency Violations for interfaces through the use of script commands and SimAuto

Bug Fixes

• Auxiliary Files: Using the area/zone filtering option on the Auxiliary File Export Format Description was not working properly. This has been fixed.

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July 9, 2009

New Features

• Contingency Analysis: Modified the Contingency Element Dialog so that you can search for objects using labels.
• Contingency Analysis: Modified the Contingency Element Dialog so that when search for Branch objects a drop-down appears that allows you to choose the Branch Device Type which you are looking for.
• User Interface Dialogs: Added support in the Difference flows for comparing the custom floats, custom integers, custom strings, and Memo fields for all objects.
• User Interface Dialogs: Added support in the Difference Flows for showing the difference in the area or zone names and numbers
• User Interface Dialogs: Added support in the Difference Flows for comparing ownership information allow you to see how the ownership of devices changes.
• User Interface Dialogs: Added ability to access the lists of removed objects using script command. The object names all start with the string "Removed". For example RemovedBus, RemovedGen, etc...
• User Interface Dialogs: Added a new field called "Difference Flows\In Diff. Flows Base Case?" for all the object types which store Difference Flows base case information. This field will be YES if this object is in the base case and NO if it is not.

Bug Fixes

• Case Information Displays: Modified the branch case information displays which show only those of a particular Branch Device Type so that the Find... feature of the case information display limits the branches by Branch Device Type.
• Contingency Analysis: When showning the substation information for a limit violation on a branch, an error would occur if the branch's terminal buses did not belong to a substation. This has been fixed.

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July 23, 2009

New Features

• Auxiliary Files: When using the MOVE script command with switched shunts, allow only the ID of the shunt to be changed (the bus stays the same). This follows what is allowed with loads.
• Auxiliary Files: Added ability to specify a particular PTI or GE file version in the OpenFileType parameter of OpenCase()
• Auxiliary Files: Added more optional options to the OpenCase() script command to support specifying options when opening an EPC or RAW file.
  For RAW files, the format is
  OpenCase("filename", OpenFileType, [LoadTransactions, StarBus]);
                                      YES               NEAR
                                      NO                MAX
                                      DEFAULT           10000
  For EPC files, the format is
  OpenCase("filename", OpenFileType, [MSLine,     VarLimDead, PostCTGAGC]);
                                      MAINTAIN    Number      YES
                                      EQUIVALENCE             NO
• Case Information Displays: Added access for Island records to the island slack bus generator fields for MW, Mvar, Max MW, Min MW, Max Mvar and Min Mvar.
• Contingency Analysis: Added a new option to the Contingency Elements for Injection Group "Set To" or "Change By" actions to specify that the amount of generation change should be achieved by opening generators instead of changing their MW output. When the amount of change needed is negative generators will be opened until the amount opened exceeds to user-specified change.
• Integrated Topology Processing: Added options to select only a single bus per super bus for PV/QV tracking and QV curve tracing. This is access through either a button click on the appropriate dialogs or through a new script command with no parameters call "PVQVTrackSingleBusPerSuperBus".
• Oneline Diagrams: Modified the drawing of Substation display objects to force them to have a size of at least 1 pixel. Normally as you zoom out, when objects become very small they completely disappear. Bus display objects and substation display objects are now the only exceptions to this which always draw at least a single pixel.
• PV and QV Curve Tool: Added options to select only a single bus per super bus for PV/QV tracking and QV curve tracing. This is access through either a button click on the appropriate dialogs or through a new script command with no parameters call "PVQVTrackSingleBusPerSuperBus".
• Power Flow Solution: Augmented the new feature from the June 30 patch regarding setting transformers to use line drop compensation to regulate a point an impedance away from the regulated bus of the transformer. The impedance can now include both a resistance and a reactance.
• SimAuto: Added a new SimAuto function called "GetCaseHeader(filename)". By passing in a filename to the procedure, Simulator will extract the Case Header information from the file. The return value of the function will be of a format similar to other SimAuto command. Result(0) will an error string that is blank if no error occurs. Result(1) will be an array of strings containing the contents of the Case Header or Description of the PWB file.

Bug Fixes

• Contingency Analysis: Fixed error when re-opening the contingency element dialog for a contingency action involving a Generator, Load or Shunt Set To or Change By action. When re-opening the dialog the object would not be properly chosen.
• PV and QV Curve Tool: When using the Integrated Topology Processing in conjunction with the PV curve tracing it was possible that the PV curve would abort prematurely due to a bus becoming disconnected. This has been fixed.
• User Interface Dialogs: Cleaned up some issues with fields not being filled in correctly when opening the Calculated Fields dialog with an already existing calculated field.
• User Interface Dialogs: Fixed potential error on the TLR dialog when re-opening the dialog after previously selecting a branch using labels.
• User Interface Dialogs: On the switched shunt dialog, when changing the bus or ID of an existing shunt, user is now prompted if a new shunt should be created or the existing one should be moved instead of just creating a new shunt. This makes the shunts more consistent with how loads are handled.

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July 27, 2009

New Features

• Case Information Displays: Added the ability to see a list of all the Conditions of an Advanced Filter and thus interact with the filter conditions through Copy/Paste with Excel and through the DATA section of auxiliary files.
• User Interface Dialogs: Modified the Difference Flows feature to permit the comparison of cases using either labels or Secondary Key fields (Name/Nom kV) as the key field for the comparison.

Bug Fixes

• Power Flow Solution: Fixed a bug that would cause a bus not to properly reenergize itself after being taken out of service in some situations.

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August 10, 2009

New Features

• Auxiliary Files: Added support for reading and writing the Post Power Flow Solution actions through a separate AUX file DATA type to allow access in a way other than the SUBDATA section of the AUX file.
• Auxiliary Files: The script command Scale() was restricted to use in Edit Mode. This restriction has been removed so that the command can be used in any mode. This was necessary to allow the command to be used as part of the Time Step Simulation.
• Case Information Displays: The field indicating if a reactive capability curve is in use for a particular generator is now included with the reactive capability curve point records.
• Case Information Displays: Ownership information can new be defined through the three-winding transformer record. All two-winding transformers which represent the three-winding transformer belong to the same owner as the three-winding transformer.
• Contingency Analysis: The contingency element for setting or changing a injection group MW output by opening generators in merit order has been modified. Generators are now opened until a generator will exceed the desired total change. If a generator will exceed the desired amount it is not opened, but the remaining generators continue to be processed in merit order and are opened if the total change does not exceed the amount desired.
• PV and QV Curves: Added nominal kV along with bus name when displaying bus identifiers for selecting the values that should be plotted for PV or QV tracked quantities.
• User Interface Dialogs: When moving equipment by right-click on buses on the oneline diagram, the anchoring is not properly updated and deviced graphically moved to connect to their new buses as appropriate.

Bug Fixes

• File Formats: Fixed an access violation that could occur when writing out a RAW file if the name of the limit group "Default" was changed.
• File Formats: Fixed an access violation that could occur when writing out a RAW file if a switched shunt that was modeling a FACTS device was out of service.
• User Interface Dialogs: When using the Move Equipment Dialog, the ID of switched shunts was not being maintained if the shunt was moved to a bus that already had shunts at it. This has been fixed so that as long as the ID remains unique it is maintained.

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August 18, 2009

New Features

• Auxiliary File: Added a new script command for Renumber3WXFormerStarBuses("filename"). The script reads in a text file which contains the renumber information. Each row of the text file contains 6 entries: Primary Bus Number, Secondary Bus Number, Tertiary Bus Number, Circuit ID, New Star Bus Number, New Star Bus Name. The first four fields are used as a key to lookup the three-winding transformer records, and the last two fields are used to renumber and rename the bus. If the new bus number is already used in the case the record is ignored. Also, the first three fields can be specified as the "name_kv" instead of the number.
• Contingency Analysis: Added an option when saving the Contingency Analysis Auxiliary File to use DATA sections for objects such as Violations, Contingency Elements, Interface Elements, etc. instead of writing these objects inside of the SUBDATA sections.
• File Formats: Added the ability to renumber three-winding transformer star buses. The option is available on the Tools Ribbon under the Edit Mode Tools Renumber Menu. It is also available under the three-winding transformer's case information records menu. See the new Auxiliary File feature for more description on the renumbering file format.
• Oneline Diagrams: Added a Simulator Option under the Onelines Tab to "Automatically Show Full when opening any oneline". This option applies to all online diagrams when they are opened.

Bug Fixes

• Available Transfer Capability: When loading in an auxiliary file, don't create ATCExtraMonitor unless the object being monitored exists. This was causing an access violation.
• Memory : When deleting a bus, added checks to make sure that any gen that is remotely regulating that bus is set off AVR and set to regulate its own terminal. Otherwise access violations could occur.
• Oneline Diagrams: When opening a oneline diagram as an AXD file and specifying that it open directly into the 3D mode, some of the text was not appearing. This has been fixed.
• Oneline Diagrams: Changed the default digits when saving an AXD file for the "Stack" object so that more digits are kept.

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August 21, 2009

New Features

• Case Information Displays: Modified the "Label" field to always show the primary field for the object instead of always showing a blank value.
• Oneline Diagrams: Modified the Line Flow Objects so to have an option to "Show Complex Flow (MW+jMvar)" values.

Bug Fixes

• Auxiliary Files: When reading an AUX file, modified the generator GenMW field to ensure it is always read BEFORE the GenAGCAble field. This is done because when changing the GenMW field, Simulator by default sets the AGC status to NO. By reading the AGC status AFTER the GenMW field we ensure it is set to the desired setting.
• Case Information Displays: When copying from Excel, modified the generator GenMW field to ensure it is always read BEFORE the GenAGCAble field. This is done because when changing the GenMW field, Simulator by default sets the AGC status to NO. By reading the AGC status AFTER the GenMW field we ensure it is set to the desired setting.
• General: When simultaneously executing multiple PowerWorld Simulator instances, it was possible for an error dialog to appear saying "Unable to save the license information. Please try again with administrator priviledges". This error dialog was not caused by priviledges but instead by the multiple Simulator trying to write to the same location simultaneously. This error dialog has been removed.
• Oneline Diagrams: When using the 3D oneline, little more offset was added between the contour image and the oneline diagram objects to ensure that the text fields appear on top of the contour image.
• Oneline Diagrams: Added check to prevent error when closing a oneline diagram in 3D mode while showing a contour.
• Oneline Diagrams: Modified to highlight unlinked three-winding transformer objects.
• Oneline Diagrams: When renumbering a oneline diagraming, added support for renumbering the three-winding transformer objects.

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August 24, 2009

New Features

• File Formats: When loading an EPC file, it is possible to run across two different three-winding transformers with identical star bus numbers. Simulator automatically corrects this data error by creating a new bus with an unused bus number and uses this as the star bus. An appropriate error message is written to the log.
• SimAuto: Removed the message dialog which appears to notify a user that the Automation Server can not be registered. A message log entry is added instead.

Bug Fixes

• Available Transfer Capability: When showing the multi-scenario transfer limiter results, and then clicking outside of that window, the window would disappear behind the main program window. This has been fixed.
• Case Information Displays: When clicking in the Upper-Left corner cell of a case information display, all sorting is supposed to be removed from the display. For matrix displays which show the same value for different objects in the columns, such as in Time Step Simulation, the sorting was not being removed. This has been fixed.
• Case Information Displays: Fixed error with using advanced column sorting on matrix displays.
• Case Information Displays: When using a 3-winding transformer field as part of a calculated field and then applying this calculated field to a bus object, the 3-winding transformer were counted double at the internal star bus objects. This has been fixed.
• General: Fixed an error message and resulting license failure which could occur when multiple instances of Simulator were executed simultaneously.
• Oneline Diagrams: In 3D mode, lines that were open were always drawn as dashed lines. This has been fixed.

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September 1, 2009

New Features

• Time Step Simulation: Added button on the options tab to enable the user to reset the reference case to the the present case.
• Time Step Simulation: The number of contingent violations were not being reported properly on the time step simulation dialog when set to solve contingencies in Single Solution mode. The number of violations in the contingency analysis is now reported properly.

Bug Fixes

• Contingency Analysis: An access violation could occur when editing a contingency list while having the All Contingency Violations Table open. This has been fixed.
• Oneline Diagram: Fixed the new three-winding transformer object so that it is properly renumbered when using bus renumbering.
• Oneline Diagram: Modified Generic Model Field display objects to properly appear as unlinked when appropriate.
• Oneline Diagram: All out-of-service lines were appearing as dashed when in 3D mode. They now only appear dashed in the appropriate Oneline Display option is chosen.
• Oneline Diagram: If loading an AXD file and immediately entering 3D mode, some text sizes were not properly updated and text either too small or too large. This has been fixed.
• Oneline Diagram: If loading an AXD file and immediately entering 3D mode, the option to show the contour image immediately was not working properly. This has been fixed.

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September 11, 2009

New Features

• Oneline Diagrams: Modified the mouse wheel zooming so that it zooms in on the location of the mouse cursor. Previously it zoomed in on the center of the oneline only.
• Oneline Diagrams: Modified zooming in and zooming out using the keyboard and mouse wheel so that if you go "in twice" and the "out twice" you end up at the same zoom level.
• PV Curve Tool: Added storage of the low and high voltage limit violations as a SUBDATA section of the PWPVResultListContainer object (the PV results).
• Time Step Simulation: Added option to select if the post script command should be run before or after the results are stored. Default is after.
• Time Step Simulation: Saved some options to the TSB file that had been omitted.

Bug Fixes

• Contingency Analysis: When using Solve Single Contingency in the DC power flow mode, the displayed results will reflect the correct generation dispatch due to any make-up power adjustments.
• Contingency Analysis: For Linear calculation methods, any generators that are impacted by a contingency will not be allowed to participate in the make-up power.
• Power Flow Solution: Fixed an error which could occur in the multi-terminal DC line solution if converter current ratings would be hit with all converter CLOSED, but one of the converters was presently OPEN. This could result in the converter setpoints being reduced even when it was not necessary.

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September 21, 2009

New Features

• Available Transfer Capability: When using any iterated ATC solution methods, the ATC Curve now strictly enforces a hierarchy for the various tolerances in the iteration processes. Tolerances are now adjusted according to following rules at the start of the PV process.
  (1) MVA convergence tolerance must be < (Minimum Step)/10.
  (2) Island based AGC tolerance and area tolerances must be < (Minimum Step)/2.
  (3) MVA convergence tolerance must be < 0.2*(Island based AGC tolerance) or < 0.2*(smallest area tolerance).
• Available Transfer Capability: When just using the ATC tool to ramp a transaction, the MVA convergence tolerance condition relative to either the area tolerances or island-based AGC tolerance must be met.
• PV Curve Tool: The minimum step size for the PV Curve tool is now limited to 0.1 MW or greater.
• PV Curve Tool: The PV curve tool now strictly enforces a hierarchy for the various tolerances in the iteration processes. Tolerances are now adjusted according to following rules at the start of the PV process.
  (1) MVA convergence tolerance must be < (Minimum Step)/10.
  (2) Island based AGC tolerance must be < (Minimum Step)/2
  (3) MVA convergence tolerance must be < 0.2*(Island based AGC tolerance).

Bug Fixes

• File Formats: Modified the reading and writing of EPC files to allow 12 character bus names.
• File Formats: Modified the writing out of EPC files to correctly write out an individual converter status. Previously if the entire multi-terminal DC was in service, but one converter was open it would still write out the converter as closed to the EPC file.

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September 29, 2009

New Features

• Auxiliary File Formats: Modified to objects CustomCaseInfoRow and CustomCaseInfo to automatically create a new object if one does not exist when loading from an AUX file.
• Auxiliary File Formats: For Model Expressions, the fields for "CustomExpression" and "CustomExpressionString" were required fields. These have been removed so that objects can be created without these fields.
• Power Flow Solution: Modified the angle smoothing routine in Simulator to handle the situation where two branches that were recently closed (or bypassed) are in series with one another (but with other lines in between them). Previously lines directly in series were properly handled as a group. Now the more general case with lines in series are handled as a group.
• SimAuto: Modified to objects CustomCaseInfoRow and CustomCaseInfo to automatically create a new object if one does not exist when modifying data for them.

Bug Fixes

• Auxiliary File formats: Fixed problem when reading in the "Contour" object from an AXD file if the AXD file had been generated in Chinese.
• Auxiliary File formats: Add ability to generate the contour immediately when loading an AXD file into the 2D mode.
• Power Flow Solution: Simulator was allowing a generator's MW limits to be ignored when running the economic dispatch (ED) control on an area. This can results in unreasonable results (one generator at a huge positive output and another at a huge negative output). The ED has been fixed to not allow generator limits to be ignored.
• Power Flow Solution: When using DC power flow and solving contingencies or using linearized ac method for solving contingencies, generator MW limits will be enforced if choosing to do that and max post-contingency response for generators will be enforced if also choosing to enforce MW limits.
• User Interface Dialogs: The tap transmission line dialog would not allow a new bus number with more than 5 digits. This then resulted in the user accidentally choosing a bus number of zero which caused an invalid power flow model to be created. This has been fixed.
• User Interface Dialogs: When using the choosing dialog to choose a multi-section line object, the circuit ID was not displayed in the Far bus list. This has been fixed.

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September 30, 2009

New Features

• None.

Bug Fixes

• Oneline Diagrams: The September 29 patch introduced a bug that did not allow oneline objects to be dragged.  This has been fixed.

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October 1, 2009

New Features

• Integrated Topology Processing: Added the ability on the oneline to right-click on a generator, load, switched shunt, transmission branch, or DC Line and choose to "Open Breakers to Isolate". Also added this option to these same objects in the case information displays. This option will then automatically traverse the system topology to locate a group breakers that when opened will isolate the selected device from all online generation.

Bug Fixes

• PV Curve: Fixed problem that would prevent the PV curve tool from executing if specifying an output file but not explicitly specifying the output directory. If the directory is not specified the current directory will be used.
• Time Step Simulation: When running a normal Single Solution power flow, any transaction costs associated with MW transactions are ignored. These transaction costs are only included in an Area's costs if the MW transaction is being dispatch by the OPF. A bug was occurring that caused these transactions to be included after solving a power flow solution, if an OPF had previously been run.
• Case Information Displays: Original 10/1/09 patch had an error which caused an access violation opening some case information displays.  This was fixed in a second 10/1/09 patch about 2 hours after the first patch was released.

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October 2, 2009

New Features

• None.

Bug Fixes

• Available Transfer Capability: When using ATC multiple scenarios and showing the separate dialog with one particular scenarios result, this separate dialog could not be closed after it was opened. This has been fixed.
• Oneline Diagrams: When showing flow arrows and not choosing to scale the size of the arrow proportional to the flow amount, arrows could appear on branches, loads, generators, or switched shunts that were Closed but not connected to an energized bus. This has been fixed.
• User Interface Dialogs: When using the system menu to change a dialog from Container Mode to Free-Floating modes (or vice versa), some edit boxes showing integer values could be reset to 1. This would only occur immediately after changing modes. This has been fixed.

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October 8, 2009

New Features

• Auxiliary File Formats: Added message log notifications at the beginning and end of AUX file loads.

Bug Fixes

• Case Information Displays: Allow series capacitor branch types to be changed through the Branch Device Type field.
• Contingency Analysis: All model conditions and filters are now written out with contingency options.
• Integrated Topology Processing: Fixed equivalencing to work on a full-topology model in conjunction with integrated topology processing.
• Integrated Topology Processing: Corrected bug when saving consolidated case with the option selected to convert multiple switched shunts at a bus to a single shunt with multiple blocks. The nominal shunt value was not being set correctly and an access violation could occur if the shunts contained more than 10 total blocks.
• Power Flow Solution: Fixed problem when using island-based AGC with an injection group that included constant current and/or constant impedance load components instead of all constant power. The resulting change for the load was not being accounted for correctly resulting in the possibility that a significant portion of the change would go to the system slack instead of the injection group.

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October 13, 2009

New Features

• Auxiliary Files: When exporting an AXD file of the entire oneline diagram, the fields for shapefile name and record number have been added.
• Case Information Displays: Added ability to enter a blank entry in the bus latitude/longitude fields to delete the entry.
• Case Information Displays: Added ability to enter a blank entry in the substation latitude/longitude fields to delete the entry.
• File Formats: When writing out the multi-terminal DC line converters to an EPC file, if the converter was on current control Simulator was writing a 0.0 value for the power schedule. Similarly if one power control, current schedule was written as 0.0. This has been changes so that the schedule which is not presently used is populated with the present current or power instead.

Bug Fixes

• Case Information Display: When on a Bus case information display, the editing of the SUBSTATION latitude/longitude fields was not working properly (it would edit the bus fields instead). This has been fixed.
• Optimal Power Flow: When calculating an area's cost including MW Transaction costs, Simulator was treating the cost of the transaction to be equal to the price at which the transaction was dispatched multiplied by the amount of the transaction. This was incorrect, the cost is now calculated as the integral under the transaction cost curve.
• Optimal Power Flow: When calculating an area's cost including MW Transaction costs, only areas that were on OPF control were including the MW transactions costs. This has been changed so that all areas include the MW transaction costs.

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October 15, 2009

New Features

• None.

Bug Fixes

• Contingency Analysis: When using the "Open With Breakers" contingency element on a Bus object, an access violation would occur. This has been fixed.
• Power Flow Solution: If a phase shifter is in-service, but removing the phase shifter will split this system into two islands, then that phase-shifter can not regulate the flow on itself. Trying to do so in the DC power flow resulted in oscillating behavior. Previously, a nearby look was done to see if this was the case. Some cases were more complicated though, so a generic routine has been added to prevent these phase shifters from regulating.
• Time Step Simulation: Fixed an error when saving a TSB file if any of the schedules have no schedule points.

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October 16, 2009

New Features

• PV Curve: When ramping injection groups in a PV curve trace, an AGC tolerance is used. This tolerance is related to how far the slack bus output can be from its desired output. A typical value is 2.0 MW. This worked correctly for a single PV curve step, but the tolerance was applied independently at each PV curve step, and thus the slack could under (or over) generator by 2.0 MW at every step. The error could then accumulate over the course of the dozens of steps used in the PV curve trace. This has been fixed so that the slack bus output error does not accumulate during the PV curve trace.

Bug Fixes

• Time Step Simulation: Fixed a memory leak that occurred when applying schedule subscriptions at each time point. The memory leak was small, but was proportional to the number of schedule subscriptions and would occur at every time point. Thus if you had a large number of schedule subscriptions and a large number of time points the memory leak became large.
• User Interface Dialogs: On the Run Mode multi-section line dialog, saving of information on the Custom tab was not working. This has been fixed.
• User Interface Dialogs: Fixed an access violation that could occur when loading an Auxiliary file which switched into Edit Mode multiple times, while at the same time having open a dialog (such as Time Step or Contingency Analysis) which is not allowed during Edit Mode.

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October 23, 2009

New Features

• Available Transfer Capability: Added more checks within the iterated ATC methods to more quickly ABORT the ATC process if the user clicks abort.
• Contingency Analysis: modified the contingency action which changes or sets the MW Setpoint of a phase shifter so that it now automatically turns the phase shifter onto control. Previously if the phase-shifter was not already on control the setpoint would change but this wouldn't do anything because it wasn't on control.
• Optimal Power Flow: Modified the PWLPTabRow object to allow script commands to obtain the LP Basis Matrix (using variable names LPBasisMatrix:X) and the full LP Tableau (using variable names OPFCNAin:X).

Bug Fixes

• Power Flow Solution: When model phase shifters as discrete controls, sometimes a phase shifter could get stuck one step away from its minimum or maximum phase shift. This has been fixed so that it can achieve the full minimum or maximum.
• Power Flow Solution: Implemented changes for keeping track of constant power, current, and impedance loads when using island based AGC with an injection group. Loads in the source and sink injection group will be adjusted to account for changes in voltage affecting the total load from the components. This is relevant for power flow, ATC, and PV.
• SimAuto: Modified SimAuto so that registering and unregistering SimAuto doesn't require a new license key. This prevents the problem where when Simulator is elevated on Windows Vista and Windows 7.
• Time Step Simulation: Changing the way schedules are applied to time points. Presently if the schedule does not contain a value at a time point and the interpolation is not enabled, then the value of the field in the case is returned. I have changed it so that the schedule is appies the last value in the schedule instead of the value in the case

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October 27, 2009

New Features

• Oneline Diagrams: Modified the drawing of Line Flow Arrow objects to bias the drawing text to the left of arrows that are directly vertical. Previously arrows that were at exactly +90.0000 degrees and arrows at -90.000 degrees would have arrows drawn on opposite side of on another.  Now arrows near +/- 90 degrees will be biased to draw to the left to make them consistent.

Bug Fixes

•  Contingency Analysis: Mistake was made in the 10/23/09 patch regarding the new feature to turn on transformer control when defining a contingency element which changes the MW setpoint. This has been fixed.

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November 2, 2009

New Features

• Auxiliary File Format: Added new parameters to the script command CTGWriteResultsAndOptions(). Parameters after the "filename" below are new optional parameters which correspond to the settings that are available on the dialog that appears in the GUI when saving a list of contingencies.
  
  CTGWriteResultsAndOptions("filename",[opt1, opt2, opt3,…opt9],KeyField,UseDATASection);
  Each entry in the Option Settings parameter, [opt1, opt2, … opt9], is either a YES or NO entry corresponding to the following options. If not specified or blank, the default entry given for each will be used.
  Opt1 – Save unlinked contingency actions, default = NO
  Opt2 – Save Contingency Options, default = YES
  Opt3 – Save Limit Monitoring Settings, default = NO
  Opt4 – Save General Power Flow Solution Options, default = YES
  Opt5 – Save List Display Settings, default = NO
  Opt6 – Save Contingency Results, default = YES
  Opt7 – Save Inactive Violations, default = YES
  Opt8 – Save Interface Definitions, default = NO
  Opt9 – Save Injection Group Definitions, default = NO
  
  KeyField indicates the identifier that should be used for the data. Valid entries are PRIMARY, SECONDARY, or LABEL. The default setting is PRIMARY. PRIMARY will save using bus numbers and other primary key fields. SECONDARY will save using bus name and nominal kV and other secondary fields. LABEL will save using device labels. If no labels are specified then the primary key field will be used.
  
  UseDATASection – set this to YES or NO. If YES, data that by default is specified using SUBDATA sections will instead be specified using DATA sections. For example, the actions that define a contingency by default are specified using a SUBDATA section. If choosing to use the DATA section instead, each action will be specified in a DATA record belonging to the ContingencyElement objecttype.

Bug Fixes

• Auxiliary File Format: When invoking the script command ExitProgram, Simulator was popping up a dialog box prompting the user to save the case. This has been fixed so that no dialog box is shown when calling ExitProgram.
• Power Flow Solution: When performing tap balancing on parallel transformers which have different transformer step sizes, some situations occurred which resulted in oscillating transformer taps and a failed power flow solution. This has been fixed.
• User Interface Dialog: Fixed access violation which could occur on the Dynamic Formatting Dialog for a specific oneline diagram when invoking the advanced filter dialog.

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November 12, 2009

New Features

• Case Information Display: When right-clicking on the substation list and saving to an Auxiliary file, the user is prompted to save a list of buses and which substation they are assigned to. Previously it would save all buses and list the substation as blank if the bus did not belong to a substation. The feature will now only list buses that belong to a substation.
• User Interface: Added new feature to show the Long Line Voltage Profile across a transmission line. This is available by right-clicking on a transmission line on either a oneline diagram, bus view, or case information display. On the case info display you may select multiple branches and right-click to view the profile across all of the selected branches. This will show a graph with the per-unit voltage profile as the Y-Axis and the X-Axis will go from 0% (from bus) to 100% (to bus).

Bug Fixes

• File Formats: Fixed up the loadng of a PTI *.drw file. Bus objects were not being properly draw. Generator and load fields were not being properly read in. Also, it has been modified to skip "TT...EN" records in the file. Previously it would abort reading when encountering a TT record.
• Memory: When deleting bus records that were connected to a multi-terminal DC converter, the memory link from the MTDC Converter to the bus was not properly cleaned up which resulted in an access violation. This has been fixed.
• User Interface Dialogs: When using the equivalencing dialog and choosing to save the external system as a PWB file, previously an error could occur when loading the PWB file back in if the external system did not include all three-winding transformer. This has been fixed so that old PWB files written this way will properly load.
• User Interface Dialogs: When using the equivalencing dialog, added the ability to properly save the external system as an EPC file. Previously it would always just save the entire EPC file.

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November 18, 2009

New Features

• User Interface: Added a similar Long Line Voltage Profile across a multi-section line as done in the 11/12/09 patch. Each line section is represented by a 100 range on the x-axis (e.g. the third section goes from 200% to 300%.) Also, a section representing a series cap or transformer will be represented by a dotted straight line.

Bug Fixes

• Available Transfer Capability: Fixed a problem which could occur when ramping a transfer causing it to ramp too far if power flow solutions were not successful at the initial transfer step. (Could be a problem for either in the positive or negative transfer amount).
• File Formats: Fixed potential error which could occur when loading in a PWB file containing unlinked interface elements.
• Memory: Fixed bug introduced by the memory fix in 11/12/09 patch which resulted in ALL multi-terminal DC line records being deleted when ANY bus was deleted.
• QV Curves: The checkbox on the QV curve Options, for saving results to a file was not working properly.  This has been fixed.

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December 1, 2009

New Features

• File Formats: Added ability to read the new NERC Book of Flowgates directly from the CSV file format now used.

Bug Fixes

• Case Information Displays: Fixing a problem that causes Super Area Marg Cost Min = Super Area Marg Cost Max always. The min and max were not taken properly.
• Contingency Analysis: Changes for correctly writing out contingency monitoring exceptions using labels when using CTGWriteResultsAndOptions script or when saving all contingency related info from the contingency dialog.
• Oneline Diagram: Fixed a bug with oneline double clicking that could under rare circumstances cause an access violation upon further mouse clicks on a oneline.
• Time Step Simulation: Pasting scheduling subscriptions into the Time Step Simulation dialogs by copying from a spreadsheet was not working properly. This has been fixed.
• Time Step Simulation: Added ability to include minutes seconds and milliseconds in the name of the auto generated contour files.
• User Interface: Fixed potential solution errors that could occur while animating a solution and simultaneously opening a breaker. It was possible in this situation for Simulator to change the status of a branch in the middle of the OPF or Power Flow solution causing an invalid solution to occur while animating. This would be fixed on the next animation step as long as a solution was achieved, but if the solution failed the animation would just stop. Solution failure was certain if opening the branch isolated a bus.

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December 2, 2009

New Features

• None.

Bug Fixes

• Power Flow Solution: Fixed an extremely rare situation that could cause solution trouble if multiple generators at the same bus had very small Mvar ranges.

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December 21, 2009

New Features

• PV Curve: When writing values out to an AUX file for PV results, values below 0.001 are now written using scientific notation to ensure small values can be viewed properly.
• PV Curve: Implemented option to track inadequate voltages with the PV tool, display them, and save/load from auxiliary file.
• PV Curve: When saving PV states to a PWB or AUX file, turn off AGC for the entire case to avoid confusion when these cases are examined.
• Integrated Topology Processing: Added ability to load a CSV file generated using the HDBExport command with an appropriate pattern file. This loads the entire EMS system model in as a case.

Bug Fixes

• Auxiliary Files: When loading a case using the auxiliary file format, it was possible to create branch records which had the same key fields. We were only checking to see if an existing branch existed, so if the same branch were listed twice in the AUX file it could be created twice. This has been fixed.
• Contingency Analysis: When using the DC approximation and running the contingency analysis, regardless of Limit Monitoring Settings or other settings related to amp flow, the flows and limits will be based on MVA/MW.
• Fault Analysis: Modified editing of the internal generator impedance so that writing these impedances back out to a PTI raw files is done correctly.
• Oneline Diagrams: If a oneline associated with a PWB file is maximized when the PWB is saved, the oneline will open maximized when the PWB is opened. Fixed bug that would not properly maximize onelines if they are opened while other forms are maximized.
• Sensitivities: When calculating voltage sensitivities to a transfer, switched shunts that are on continuous control and located at buses participating in the transfer can be set to fixed by using the option that also turns generators at these buses off AVR control.

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December 22, 2009

New Features

• None.

Bug Fixes

• Fault Analysis: Fixed handling of line-to-line fault calculation when a fault impedance value is specified. Previously the fault impedance value was always assumed to be zero regardless of user input.
• Optimal Power Flow: New feature from the October 23 patch related to writing out LP Tableau and LP Basis Matrix was not fully functional and has now been fixed.

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December 30, 2009

New Features

• Fault Analysis: Added a new object type Fault_Options allowing the change of fault options from an AUX file. The variable names are FAFaultCurDisplayAmps, FAIECPowerFactor, FAIECVolt, FAPreFaultProfile, FASetLineCharging, FASetShuntElements, and FASetTRRatio

Bug Fixes

• File Formats: Fixed potential access violation if Areva EMS CSV file had an LN record referring to a LNLIM record which did not exist.

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December 31, 2009

New Features

• File Formats: Added error messages when checking integer lookups while reading from the Areva CSV file format to better communicate any minor problems encountered.

Bug Fixes

• None.

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January 12, 2010

New Features

• File Formats: Added population of the first CustomString field bus, gen, load, switched shunt, and branch objects when reading from the Areva CSV file format. This field contains the very short "ID" read from the CSV file which is not unique in general but appears to be unique inside of a single substation. This ID is very short and useful on oneline diagrams.
• File Formats: Added population of labels for substations, areas, and zones when reading from the Areva CSV file format.
• General: Added support for the name of a substation to be the secondary key field.
• Oneline Diagrams: When right-clicking on a multi-section line display object a oneline diagram, access to the option "Show Long Line Voltage Profile" has been added. This applies to the bus view as well.

Bug Fixes

• Contingency Analysis: Fixed potential access violation which may occur after performing "Join Active Contingencies..." on your active list of contingencies and a list of contingencies in an AUX file. The access violation would be while running the Contingency solutions. After saving the case or AUX file list of contingencies and then reopening them, this error would have not reappeared. Regardless it is fixed in this patch.
• Contingency Analysis: In a bug fix added on 12/21/09 regarding ensuring that amp limits are not used when using the DC approximation, a bug was introduced related to monitoring of CHANGE violations or changes from a basecase violation.  If monitoring for change violations, this bug could cause inconsistent AC contingency results because the initial flows on monitored branches could be recorded in amps when they should be recorded in MVA or recorded in MVA when they should be recorded in amps. This would cause a problem when comparing the flows on branches post-contingency to their pre-contingency flows. This would not have been a problem if using the dc approximation when solving the power flow.

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January 21, 2010

New Features

• Case Information Displays: Added the ability of an object to use a calculated fields of its own object class. As an example, this allows a bus case info display to show a column with the minimum voltage of all buses.
• File Formats: Added support for reading and writing the RAW Version 32 file format.
• General: Added support throughout for switched shunt objects behaving as though they are owned by their terminal bus' owner. This affects the use Area/Zone/Owner filtering on switched shunt objects. Also added the ability to view the bus owner field of a switched shunt.
• PV Curve Tool: Add ability to use calculated fields with PV results.
• PV Curve Tool: ATC Extra Monitor values tracked with the PV results now have fields to show what the flow is at the transfer level at which the first inadequate voltage is encountered if choosing to store inadequate voltages.

Bug Fixes

• PV Curve Tool: Fixed an access violation that could occur when doing reverse transfer and the first transfer step did not solve in the base case.
• User Interface Dialogs: Fixed bug that would cause data entry problems in some special grids on user interface dialogs. Selecting a field for entry would not immediately allow you to enter data. You would have to double enter the first character to get the correct entry. Among affected grids are the MVA limits grid on branch dialogs, the reactive capability curve grid on generator dialogs, and the switched shunt block grid on switched shunt dialogs. This did NOT affect any grids in the Model Explorer.

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February 5, 2010

New Features

• Auxiliary Files: Added support for automatically writing out ATC Scenario input information using Labels
• Available Transfer Capability: Added descriptions of all the fields related to the ATC_Options to better document them. These are available when using the Export Object fields feature.
• Case Information Displays: Added ability to see a switched shunt's bus's owner in the switched shunt table. Also added being able to see the EPC owners of a switched shunt if viewing extra GE data is turned on.
• Case Information Displays: Modified a Switched Shunt to behave as though its owner is the same as its terminal bus owner. This means when using the Area/Zone/Owner filter it can be hidden using Owner filters.
• File Formats: Modified reading the Areva hdbexport format so that a LN record with a negative X value is not treated as a series cap if the LN record goes between two buses with different nominal kV values.
• Integrated Topolology Processing: Modified several various GUI messages and Message Log when performing solutions using ITP. The messages were showing identifiers such as bus number based on the post-consolidated system instead of the full-topology model.

Bug Fixes

• Auxiliary Files: Fixed error when writing out Model Expression or Model Condition information to an auxiliary file while using labels for devices which did not have a label.
• Available Transfer Capability: Modified the ATC tool to properly utilize the new special contingency actions using Open with Breakers.
• Case Information Displays: When copying an extremely large amount of text to the clipboard the interaction with Simulator's case information displays could become very slow. This has been fixed.
• Case Information Displays: Fixed the use of Toggle all YES or Toggle all NO for the switched shunt fields related to Use Continuous Element, All or Nothing, Use Target High, or Switch in Inner Power Flow loop.
• Contingency Analysis: Modified the contingency analysis to better handle situations where a contingencies contains several elements using the Open with Breakers feature. Add ability to better identify which breakers are needed to isolate which devices when a particular breaker may be needed to isolate more than one device.
• File Formats: When reading a branch record in the GE EPC file, Simulator was not handling the the ohmic flag, and thus the R, X, and B value could be read incorrectly if the ohmic value was 1. This has been fixed.
• Oneline Diagrams: Fixed potential error with viewing 3D onelines with a GPU accelerated contour in Full Screen Mode.
• Optimal Power Flow: When setting up a case with multiple islands which had OPF areas on AND displatchable DC lines connecting the islands with dispatchable MW transaction between areas in the different islands, the OPF was not solving correctly. This has been fixed by adding a new constraint in this special situation for an island to ensure that the sum of DC flows out of an island was equal to the sum of area MW transactions out of the island.
• PV Curve Tool: Modified the PV tool to properly utilize the new special contingency actions using Open with Breakers.
• QV Curve Tool: Modified the QV tool to properly utilize the new special contingency actions using Open with Breakers.
• Security Constrained OPF: Modified the SCOPF tool to properly utilize the new special contingency actions using Open with Breakers.

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February 8, 2010

New Features

• None.

Bug Fixes

• Case Information Displays: The 2/5/2010 patch included a bug which made all pasting into case information displays quit working.  This has been fixed in the 2/8/2010 patch.

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February 15, 2010

New Features

• Contingency Analysis: The "Open with Breakers" algorithm was modified to allow buses with on-line generators to be traversed as long as no more than 10 such buses are encountered. If any load is traversed during the algorithm, then the statuses of the encountered on-line generators are set to OPEN along with the breakers found.

Bug Fixes

• PV Curve Tool: Changed PV analysis to perform consolidation when restoring the initial state or rerunning PV analysis if the case was initially consolidated before the first PV run.

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February 17, 2010

New Features

• File Formats: Added a YES/NO field for all GE EPC objects under the "EPC File" folder which shows "Flagged for Delete in EPC". This flag will only be set TRUE if the status is read as "-4" in the EPC file. PowerWorld would not use this flag, but a user can use the flag to create an advanced filter to choose devices to delete. This value will persist as PWB files are saved and loaded.
• File Formats: Added a field for all GE EPC objects under the "EPC File" folder which shows the "EPC Modification Status". This field will show either "None", "Created", or "Modified". This value will not be saved in any format and will be initialized to None when read from any non-EPC format. When an EPC file is ready as a case the value will be initialized to "Created". When appending a case using the EPC format, the value will be set to "Created" if a new object is created, and if an existing object is modified by appending, the value will be set to "Modified". Not object was never created by reading from the EPC file, this value will still be blank.
• Oneline Diagrams: Modified the writing of an AXD file to support writing using labels as the identifiers for the oneline display objects.

Bug Fixes

• Contingency Analysis: The use of Monitoring Exceptions to Include the monitoring of an element was not working in conjunction with the linearized AC contingency solutions. It worked correctly with either the full AC solution or the DC approximation. It now works correctly in all situations.
• File Formats: Fixed error when reading RAW version 31 or 32 formats which omitted optional parameters at the end of the FACTS records.

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February 22, 2010

New Features

• File Formats: Modified the "EPC File" extra fields for three-winding transformer branches so that the secondary and tertiary windings show the "EPC File" information stored with the primary winding.

Bug Fixes

• Case Information Displays: Fixed a bug that could incorrectly applicate apply an advanced filters which "uses another filter" if several advanced filters had the same name. Advanced Filter names need only be unique for a particular object type, but this bug occurred when filter names were the same across different object types.
• File Formats: Fixed bug that could occur when appending an EPC file containing three-winding transformers
• File Formats: Fixed error when appending multi-section transmission line using an EPC file. When appending, Simulator will now look for the multi-section line record, and if one is found data will be appended to the appropriate section.
• Time Step Simulation: Cleaned up some flickering issues when animating a oneline diagram in the time step simulation which contained a contour image.

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February 23, 2010

New Features

• File Formats: Modified log messages when reading EPC files with devices with status=-4.

Bug Fixes

• Optimal Power Flow: Adding the new constraint for island MW controls in patch for Feb. 5, 2010, inadvertently causes the loading of OPF results from older PWB files to work incorrectly. This has been fixed.

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March 4, 2010

New Features

• File Formats: Added a new option under the Save As menu in many case information displays called "Save As\GE EPC Format (only selected records)". This feature will generally save out the selected records as an EPC data section (for some object types there may be multiple sections).

Bug Fixes

• User Interface Dialogs: When opening the bus dialog by right-clicking on a bus oneline object and choosing show dialog, it was possible to inadvertently relink the bus oneline object by navigating to a new bus. Linking the oneline object to a different bus should only be possible by clicking on the Link to New Bus button.
• Integrated Topology Processing: When using Integrated Topology Processing, the reference state was not always handled properly.
• Integrated Topology Processing: Fixed an odd bug that occurred if (1) using the Open with Breakers contingency events and (2) using integrated topology processing. When opening the contingency dialog and choosing to "Set the contingency analysis reference state to the current case", the element statuses would not be reflected in the new reference state. If manually choosing to "Set as Reference" this was not a problem, but if simply running the contingency analysis immediately the element states would be reset to original reference state values.

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March 9, 2010

New Features

• None.

Bug Fixes

• Contingency Analysis: Fixed potential access violation when using the Convert to Device Contingencies options.
• File Formats: Modified the reading of EPC files to properly show the modifications status of Interfaces and Interface Branches after appending an EPC file to a case.
• User Interface Dialog: Fixed potential access violation when adding a bus object to a oneline diagram.

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March 18, 2010

New Features

• Oneline Diagrams: Modified how intermediate points on transmission lines would move when dragging the buses to which the lines was anchored to behave more consistently.
• Power Flow Solution: Added a new Regulation Type for switched shunt objects which allow them to regulate the sum of their Mvar output with the Mvar summation of all generators with "Wind Control Mode = Constant Power Factor" marked to regulated the same regulated bus as the shunt.

Bug Fixes

• File Formats: When loading an EPC file, modified bus objects to be labeled as "Flagged for deletion by EPC" when a bus type of -4 was read.
• File Formats: When saving out an EPC file, fixed a potential problem with writing out the incorrect section number of some branches of multi-section lines.
• User Interface Dialogs: Fixed a problem with setting the current path when opening a case in Windows Vista and Windows 7.0. This could impact the automatic opening of TSB files and Auxiliary files when opening a case.
• User Interface Dialogs: Fixed potential access violation that could occur when saving a oneline diagram which contained many model field and text objects.

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March 19, 2010

New Features

• Power Flow Solution: Added a new Wind Control Mode for a generator called "Follow Min Mvar Capability Curve".  When on this mode, the Mvar output of the generator is always set equal to the value determined from the reactive capability curve's minimum Mvar value for the present MW output.
• Power Flow Solution: For switched shunts set to regulate "Wind Mvar", modified the control to ensure that the Mvar output is synchronized with the generator Mvar output prior to a power flow solution.  This helps with power flow convergence when modifying the Mvar output of these wind generation plants.

Bug Fixes

• None.

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March 30, 2010

New Features

• PV and QV Curve Tool: When choosing to save all states and encountering critical scenarios, the base case state with the transfer implemented will be stored for all transfer levels that are solvable for critical scenarios before the final critical transfer level is found. Previously, states were only saved for the critical scenario itself.

Bug Fixes

• Case Information Displays: The use of Calculated Fields as applied to an owner object was not working properly and yielding strange results. This has been fixed. This error would also affect using non-owner advanced filters with an owner object.
• File Formats: After loading an EPC file and populate the GE EPC fields for load records, Simulator was not properly saving this information to the PWB file format. As a result the GE EPC fields for Load records was lost. This has been fixed.
• Oneline Diagrams: When saving a case using the file type PWB with Options, the PWB file was saved appropriately, but if any diagrams were open they were saved in Version 14 format regardless. This has been fixed so that the PWD version is synchronized the PWB version.
• Time Step Simulation: Added the ability to paste from Excel (and read from an AUX file) the Skip and Solution Type columns for the Time Step Simulation time point records.
• Time Step Simulation: When plotting data in the Time Step Simulation versus time, the plotting routines were truncating the time variable so that it was only accurate to 5 minutes intervals. As a result, the plotting of data if time steps were less than 5 minutes was not working properly. This has been fixed.

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March 31, 2010

New Features

• None.

Bug Fixes

• Case Information: Added back in support for custom expressions to use the following commands. This had been inadvertently removed. (Exp2,Log2,Exp10,Log10,ASin,ACos,Sec,Csc,Cot,SinH,CosH,TanH,CotH,SecH,CscH,ASinH,ACosH,ATanH,ACotH,ASecH,ACscH)
• Case Information: Loading of user defined case information displays back in from a PWB file was not working properly. This has been fixed.
• Case Information: Fixed bug Owner records which prevented all appropriate calculated fields form begin available for use.
• Oneline Diagrams: When saving an AXD file, substation objects and substation fields did not properly save their substation name or number. This made loading the AXD file back in not properly load the substations..

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April 2, 2010

New Features

• None.

Bug Fixes

• Available Transfer Capability: Modified how ATC results are filtered. For the single-linear step calculation, we now store the top limitations with each element and contingency according to the common options maximum lmiters per element and contingency. We then combine all limiters into a single table sorted by transfer MW limit, element, and contingency. We then process this list in order choosing the required number of results while enforcing the maximum mw limitation, number of elements, and number of contingencies. In previous version of Simulator 14 we only kept the limiters that were both limiting for the element and contingency. The new method will tend to report more results, especially when one contingency or one element had many transfer limiters.

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April 6, 2010

New Features

• Auxiliary Script Commands: Added new script command AppendCase(). This command has the same parameters as the OpenCase() command, except for the list of optional parameters when opening a RAW file. The optional parameter regarding creating MW transactions related to loads is not included and is assumed to be NO when using AppendCase.
• Auxiliary Script Commands: Added a new script command CTGWriteFilePTI("filename",BusFormat, TruncateCTGLabels). The first parameter is the name of the text file to write to. The second parameter is either Number, Name8, or Name12 to specify to write identifiers using either numbers, 8 character bus names, or 12 character bus names. The third parameter is either YES or NO depending on whether you would like the output to truncate contingency names to 12 characters.

Bug Fixes

• File Formats: When appending a case using PTI RAW or GE EPC files, Simulator was not replacing the existing ownership information of and object and was instead just appending to the existing ownership. This has been modified so that when appending to an objet all existing ownership information for that object is removed and replaced with what is in the RAW or EPC file.
• File Formats: When reading the EPC ownership records and retaining the extra EPC fields, an extra colon character (:) was not properly accounted for making the read of the extra EPC fields incorrect. This has been fixed.
• File Formats: Added ability to see EPC fields for ownership records. This had previously been omitted.
• File Formats: An error existed when reading an EPC file which contained a comment line (starting with #) that also included a slash character (/). The error resulted in Simulator skipping the line of text after the slash character. This has been fixed.

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April 9, 2010

New Features

• Integrated Topology Processing: Added an optional parameter to the end of the SaveConsolidatedCase() script to specify the format of the contingency file if saving using the PTI format.

Bug Fixes

• None.

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April 13, 2010

New Features

• None.

Bug Fixes

• File Formats: Fixed an access violation that occurred when reading in the Areva EMS *.csv file format.
• File Formats: Added proper error checking when writing out the DateIn and DateOut fields to an EPC file to ensure only integers are written out. Previously an error could occur when writing out the EPC record.

April 27, 2010

New Features

• Case Information Displays: Added a new feature available under the Branch Records submenu on a case information display showing branch records called Merge Terminals. This will merge line terminals for each selected transmission branch one at a time. When merging terminals, prior to removing the branch all devices connected to each terminal of the line will be moved to connect to one bus. Normally, the from bus of the line being removed will be maintained, but if the line being removed is the first or last section of a multi-section line record, then the bus representing the terminals of the multi-section line record will be maintained instead. Also for multi-section lines, if the terminal merging results in a multi-section line with fewer than 2 sections, then the multi-section line record is removed from the case as well.
• Auxiliary Files: Added a new script command called MergeLineTerminal(filter). The only parameter of the script command is a filter parameter, which must be populated with either the name of an advanced filter (with the name in quotation marks) or with the text SELECTED (no quotation marks.) If an advanced filter is given, Simulator will find all branches that meet the advanced filter definition, and will individually merge the line terminals of each line one at a time. See the Case Information Displays feature for more information..

Bug Fixes

• None.

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April 29, 2010

New Features

• Contingency Analysis: When looking for the post-contingency AUX file, Simulator looked in the current directory (which can change when opening files) or the file path specified with the post-contingency aux file if any. An extra check has been made so that if the file is not found in either of these locations, then Simulator will also look in the directory from which the present case (PWB, RAW, EPC, etc...) file was loaded.

Bug Fixes

• None.

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April 30, 2010

New Features

• None.

Bug Fixes

• Contingency Analysis: Fix a highly unusual situation in which an unsolved contingency was immediately followed by another contingency which isolated only part of a multi-terminal DC line. This combination of events would cause an access violation.

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May 13, 2010

New Features

• File Formats: Changed the label format for the labels assigned to objects when reading in a hdbexport case file. They now follow the convention $Substation$DeviceType$DeviceID. This matches what is used to generate the object identifiers for automatically generating aliases and alias subscriptions.

Bug Fixes

• Bus View: Fixed a situation in which a parallel circuit that is parallel to another single circuit and several branches in series may not have the bus connection properly drawn for the To bus.
• Oneline Diagrams: When selecting the options to show circuit breakers for generators, loads, or switched shunts, only closed circuit breakers will be affected by this option. Open circuit breakers (indicating that Status = open) will always be shown regardless of this option setting.
• Power Flow Solution: Fixed error with automatically picking the slack bus. It was always picking the largest unit even though there is other logic that should have been used to pick the bus. For more details about how the slack bus is actually picked see the Simulator online help.

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May 18, 2010

New Features

• PV and QV Curve Tools: Modified the text file which stores all the PV Curve tracking results and the QV Curve tracking results to always use a comma as a separator in the text file.

Bug Fixes

• Integrated Topology Processing: Fixed a rare solution failure that could be occur when using the integrated topology processing in a case with an out-of-service phase shifter connected radially to one inservice bus and another dead bus..

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May 26, 2010

New Features

• File Format: In an EPC file, if branches have the same From bus, To bus, circuit ID, and section number only one of the lines is retained.  These used to be made into sections of a multi-section line.  If any of the branches is marked for deletion (status = -4) then that branch is removed.  Otherwise, the last line encountered is kept and the other lines are removed.
• Oneline Diagrams: Option of whether to draw transformer symbols as coils or circles can now be specified differently for each oneline diagram.  The option can be found on the Oneline Display Options dialog on the Display Object Options tab.  Setting the option to Default will use the Transformer Symbol option specified with PowerWorld Simulator Options (stored in the Windows Registry).

Bug Fixes

• None.

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June 3, 2010

New Features

• Auxiliary Files: Removed restrictions for the LoadAXD() script command so that it can always be used in Simulator. Previously it was only available when running SimAuto or by the PowerWorld Retriever product.

Bug Fixes

• Available Transfer Capability: Enabled the use of custom expressions with Branch Limiters (TransferLimiterBranch), Interface Limiters (TransferLimiterInterface), and Nomogram Interface Limiters (TransferLimiterNomogramInterface) tables with the ATC results.

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June 8, 2010

New Features

• None.

Bug Fixes

• File Formats: Fixed reading .CON files to also allow the key words LINE or BRANCH when reading three winding transformer contingencies.
• Power Flow Solution: Fixed a bug with transformers where under rare circumstances a transformer's sensitivity was not being reset in situations when the user chose to reset the load flow to a stored reference state. The bug was causing such a transformer's regulation capability to be suppressed in solution attempts following the reference state restoration.
• User Interface Dialogs: Fixed the Bus View menu item in the lines table pop up menu on the Owner dialog.

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June 22, 2010

New Features

• None.

Bug Fixes

• Fault Analysis: Fixed error with the handling of out-of-service switched shunt when using the IEC-909 fault calculation.
• 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.

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July 2, 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.

Bug Fixes

• Oneline Diagrams: Fixed flashing hint windows caused by interaction between navigation arrows and oneline hints.
• Oneline Diagrams: Fixed error with contour dynamic value interpretation from June 25 patch.

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July 9, 2010

New Features

• 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.

Bug Fixes

• 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

• 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.
• 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.

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.
• 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

• None.

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.

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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.

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.
• 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.
• Power Flow Solution: In the DC Power flow solution, added better handling of phase shifter switching to help with convergence.

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August 11, 2010

New Features

• Oneline Diagrams: When changing to a Saved View which specifies that a contour be shown, we now automatically refresh the contour image.

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.
• 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.

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August 30, 2010

New Features

• None.

Bug Fixes

• Integrated Topology Processing: When doing contingency analysis while using advanced limit monitoring settings and also using Integrated Topology Processing, the initial base case values associated with consolidated buses were not being stored correctly resulting in limit violations not being correct.
• Power Flow Solution: Fixed improper handling of magnetizing conductance in some locations when using the DC power flow approximation.

September 2, 2010

New Features

• None.

Bug Fixes

• 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.

September 10, 2010

New Features

• None.

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.
• 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.

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September 22, 2010

New Features

• Case Information Displays (Added in 4:30 PM Patch): 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 (Added in 4:30 PM Patch): 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.

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.

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September 27, 2010

New Features

• 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.

Bug Fixes

• Power Flow Solution: Fixed access violation that could occur when an AC bus terminal of a multi-terminal DC line was outaged.

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September 28, 2010

New Features

• 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.

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.

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October 1, 2010

New Features

• None.

Bug Fixes

• 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.

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October 5, 2010

New Features

• 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..

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.

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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.

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.

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November 17, 2010

New Features

• None.

Bug Fixes

• 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

• None.

Bug Fixes

• 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.

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December 1, 2010

New Features

• 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.

Bug Fixes

• None.

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December 10, 2010

New Features

• None.

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.
• 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.
• Oneline Diagrams: Fixed error on the Find Oneline Objects dialog when tyring to define a filter for the list of objects.
• 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

• 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.

Bug Fixes

• 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

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January 5, 2011

New Features

• None.

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

• None.

Bug Fixes

• 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.

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March 14, 2011

New Features

• None.

Bug Fixes

• 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.

March 24, 2011

New Features

• None.

Bug Fixes

• Contingency Analysis/Available Transfer Capability: It was possible to get into an infinite loop during linear contingency analysis or linear ATC analysis due to generators participating in contingency make-up power hitting limits. This has been fixed.

April 5, 2011

New Features

• None.

Bug Fixes

• Model Explorer: Fixed random access violations that could occur when using the Model Explorer.

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.

Bug Fixes

• None.

May 31, 2011

New Features

• None.

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.

August 16, 2011

New Features

• None.

Bug Fixes

• 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.

January 6, 2012

New Features

• None.

Bug Fixes

• 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.
• Simulator Automation Server (SimAuto): Fixed bug with SaveCase SimAuto function that would not allow the filetype to be specified.

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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
• User Interface Dialogs

Top

Auxiliary Files (SCRIPT and DATA Sections)

• (April 14, 2009) When loading an auxiliary file format, if branch statuses are changed to close in a set of dead buses Simulator automatically makes a reasonable initial voltage guess for the newly energized buses. While most of the time this is helpful, if the AUX file also contained voltage phasor values for the buses, then the Simulator would override these values with our own estimate. This has been changed so that any bus for which the AUX file sets either voltage magnitude or angle will not have its voltage changed by our estimation routine.
• (May 27, 2009) When loading from an AUX file (or pasting from a spreadsheet), the ability to create transient stability data linked to power system records using the power system record labels as identifiers has been added.
• (May 27, 2009) When loading from an AXD file (or pasting from a spreadsheet), the ability to create oneline display objects linked to power system records using the power system record labels as identifiers has been added.
• (June 18, 2009) Added support for moving Switched Shunt records to the Move() script command.
• (June 18, 2009) Added a new RenumberMSLineDummyBuses("filename") script command which loads in a file with the new dummy bus numbers and new dummy names and makes changes. This new feature provides script acction to the option found with the multi-section line case information display.
• (June 25, 2009) Added an optional third parameter to the MOVE() script command to specify what percentage of the object to move. This is only valid for generator or load moves.
• (June 30, 2009) Modified the SetData() script command to accept a filter name of "ALL" which means to apply this to all the objects.
• (June 30, 2009) Modified the PartPoint objects so they have access to the Selected Field and Custom Expressions of both the PartPoint object AND the related object (such as a load or gen)
• (June 30, 2009) Modified the Move() script command to better support moving a percentage of a load or generator to another bus.
• (July 2, 2009) It was not possible to apply the area/zone filters to the InterfaceElement lists. This has now been enabled.
• (July 23, 2009) When using the MOVE script command with switched shunts, allow only the ID of the shunt to be changed (the bus stays the same). This follows what is allowed with loads.
• (July 23, 2009) Added ability to specify a particular PTI or GE file version in the OpenFileType parameter of OpenCase()
• (July 23, 2009) Added more optional options to the OpenCase() script command to support specifying options when opening an EPC or RAW file.
  For RAW files, the format is
  OpenCase("filename", OpenFileType, [LoadTransactions, StarBus]);
                                      YES               NEAR
                                      NO                MAX
                                      DEFAULT           10000
  For EPC files, the format is
  OpenCase("filename", OpenFileType, [MSLine,     VarLimDead, PostCTGAGC]);
                                      MAINTAIN    Number      YES
                                      EQUIVALENCE             NO
• (August 10, 2009) Added support for reading and writing the Post Power Flow Solution actions through a separate AUX file DATA type to allow access in a way other than the SUBDATA section of the AUX file.
• (August 10, 2009) The script command Scale() was restricted to use in Edit Mode. This restriction has been removed so that the command can be used in any mode. This was necessary to allow the command to be used as part of the Time Step Simulation.
• (September 29, 2009) Modified to objects CustomCaseInfoRow and CustomCaseInfo to automatically create a new object if one does not exist when loading from an AUX file.
• (September 29, 2009) For Model Expressions, the fields for "CustomExpression" and "CustomExpressionString" were required fields. These have been removed so that objects can be created without these fields.
• (October 8, 2009) Added message log notifications at the beginning and end of AUX file loads.
• (October 13, 2009) When exporting an AXD file of the entire oneline diagram, the fields for shapefile name and record number have been added.
• (November 2, 2009) Added new parameters to the script command CTGWriteResultsAndOptions(). Parameters after the "filename" below are new optional parameters which correspond to the settings that are available on the dialog that appears in the GUI when saving a list of contingencies.
  
  CTGWriteResultsAndOptions("filename",[opt1, opt2, opt3,…opt9],KeyField,UseDATASection);
  Each entry in the Option Settings parameter, [opt1, opt2, … opt9], is either a YES or NO entry corresponding to the following options. If not specified or blank, the default entry given for each will be used.
  Opt1 – Save unlinked contingency actions, default = NO
  Opt2 – Save Contingency Options, default = YES
  Opt3 – Save Limit Monitoring Settings, default = NO
  Opt4 – Save General Power Flow Solution Options, default = YES
  Opt5 – Save List Display Settings, default = NO
  Opt6 – Save Contingency Results, default = YES
  Opt7 – Save Inactive Violations, default = YES
  Opt8 – Save Interface Definitions, default = NO
  Opt9 – Save Injection Group Definitions, default = NO
  
  KeyField indicates the identifier that should be used for the data. Valid entries are PRIMARY, SECONDARY, or LABEL. The default setting is PRIMARY. PRIMARY will save using bus numbers and other primary key fields. SECONDARY will save using bus name and nominal kV and other secondary fields. LABEL will save using device labels. If no labels are specified then the primary key field will be used.
  
  UseDATASection – set this to YES or NO. If YES, data that by default is specified using SUBDATA sections will instead be specified using DATA sections. For example, the actions that define a contingency by default are specified using a SUBDATA section. If choosing to use the DATA section instead, each action will be specified in a DATA record belonging to the ContingencyElement objecttype.
• (February 5, 2010) Added support for automatically writing out ATC Scenario input information using Labels
• (April 6, 2010) Added new script command AppendCase(). This command has the same parameters as the OpenCase() command, except for the list of optional parameters when opening a RAW file. The optional parameter regarding creating MW transactions related to loads is not included and is assumed to be NO when using AppendCase.
• (April 6, 2010) Added a new script command CTGWriteFilePTI("filename",BusFormat, TruncateCTGLabels). The first parameter is the name of the text file to write to. The second parameter is either Number, Name8, or Name12 to specify to write identifiers using either numbers, 8 character bus names, or 12 character bus names. The third parameter is either YES or NO depending on whether you would like the output to truncate contingency names to 12 characters.
• (April 27, 2010) Added a new script command called MergeLineTerminal(filter). The only parameter of the script command is a filter parameter, which must be populated with either the name of an advanced filter (with the name in quotation marks) or with the text SELECTED (no quotation marks.) If an advanced filter is given, Simulator will find all branches that meet the advanced filter definition, and will individually merge the line terminals of each line one at a time. See the Case Information Displays feature for more information.
• (June 3, 2010) Removed restrictions for the LoadAXD() script command so that it can always be used in Simulator. Previously it was only available when running SimAuto or by the PowerWorld Retriever product.
• (July 16, 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.
• (December 1, 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.
• (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.

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Available Transfer Capability (ATC) Tool

• (April 8, 2009) When using the ATC method "Iterated Linear Step with Full CTG", added a check to ensure that the Post-Contingency Auxiliary File exists.
• (April 8, 2009) The ATC Dialog now allows you to open and still interact with other parts of Simulator. Care must be taken while actually running the ATC solution however now.
• (August 18, 2009) Added a new script command for Renumber3WXFormerStarBuses("filename"). The script reads in a text file which contains the renumber information. Each row of the text file contains 6 entries: Primary Bus Number, Secondary Bus Number, Tertiary Bus Number, Circuit ID, New Star Bus Number, New Star Bus Name. The first four fields are used as a key to lookup the three-winding transformer records, and the last two fields are used to renumber and rename the bus. If the new bus number is already used in the case the record is ignored. Also, the first three fields can be specified as the "name_kv" instead of the number.
• (September 21, 2009) When using any iterated ATC solution methods, the ATC Curve now strictly enforces a hierarchy for the various tolerances in the iteration processes. Tolerances are now adjusted according to following rules at the start of the PV process.
  (1) MVA convergence tolerance must be < (Minimum Step)/10.
  (2) Island based AGC tolerance and area tolerances must be < (Minimum Step)/2.
  (3) MVA convergence tolerance must be < 0.2*(Island based AGC tolerance) or < 0.2*(smallest area tolerance).
• (September 21, 2009) When just using the ATC tool to ramp a transaction, the MVA convergence tolerance condition relative to either the area tolerances or island-based AGC tolerance must be met.
• (October 23, 2009) Added more checks within the iterated ATC methods to more quickly ABORT the ATC process if the user clicks abort.
• (February 5, 2010) Added descriptions of all the fields related to the ATC_Options to better document them. These are available when using the Export Object fields feature.
• (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.

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Bus View and Substation View Onelines

• (April 8, 2009) Added ability when customizing the bus view to specify the Delta Per Mouse Click with fields so that the up/down arrow spinners are drawn appropriately.

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Case Information Displays

• (April 28, 2009) Modified the field descriptions for specific types of interface elements, participation points, or transfer limiters so that the list of fields puts fields inside folder to make it clearer where the fields come from.
• (May 20, 2009) On the Area or Zone Tie-line displays, modified the type column to show the Branch Device Type for branches tie-lines.
• (June 25, 2009) Added support for the Selected and Custom Expression fields for the GenVarLim (generator Mvar limit) records.
• (July 23, 2009) Added access for Island records to the island slack bus generator fields for MW, Mvar, Max MW, Min MW, Max Mvar and Min Mvar.
• (July 27, 2009) Added the ability to see a list of all the Conditions of an Advanced Filter and thus interact with the filter conditions through Copy/Paste with Excel and through the DATA section of auxiliary files.
• (August 10, 2009) The field indicating if a reactive capability curve is in use for a particular generator is now included with the reactive capability curve point records.
• (August 10, 2009) Ownership information can new be defined through the three-winding transformer record. All two-winding transformers which represent the three-winding transformer belong to the same owner as the three-winding transformer.
• (August 21, 2009) Modified the "Label" field to always show the primary field for the object instead of always showing a blank value.
• (October 13, 2009) Added ability to enter a blank entry in the bus latitude/longitude fields to delete the entry.
• (October 13, 2009) Added ability to enter a blank entry in the substation latitude/longitude fields to delete the entry.
• (November 12, 2009) When right-clicking on the substation list and saving to an Auxiliary file, the user is prompted to save a list of buses and which substation they are assigned to. Previously it would save all buses and list the substation as blank if the bus did not belong to a substation. The feature will now only list buses that belong to a substation.
• (January 21, 2010) Added the ability of an object to use a calculated fields of its own object class. As an example, this allows a bus case info display to show a column with the minimum voltage of all buses.
• (February 5, 2010) Added ability to see a switched shunt's bus's owner in the switched shunt table. Also added being able to see the EPC owners of a switched shunt if viewing extra GE data is turned on.
• (February 5, 2010) Modified a Switched Shunt to behave as though its owner is the same as its terminal bus owner. This means when using the Area/Zone/Owner filter it can be hidden using Owner filters.
• (April 27, 2010) Added a new feature available under the Branch Records submenu on a case information display showing branch records called Merge Terminals. This will merge line terminals for each selected transmission branch one at a time. When merging terminals, prior to removing the branch all devices connected to each terminal of the line will be moved to connect to one bus. Normally, the from bus of the line being removed will be maintained, but if the line being removed is the first or last section of a multi-section line record, then the bus representing the terminals of the multi-section line record will be maintained instead. Also for multi-section lines, if the terminal merging results in a multi-section line with fewer than 2 sections, then the multi-section line record is removed from the case as well.
• (July 7, 2010) Added ability to use other object type filters with the GenVarLim object.
• (September 22, 2010, 4:30 PM) 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.
• (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.

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Contingency Analysis Tool

• (March 17, 2009) Added support for reading/writing the global contingency actions using the objecttype GlobalContingencyActionsElement.
• (March 23, 2009) Added the ability to choose whether to include contingency options when saving contingency information to an Auxiliary File.
• (April 8, 2009) Modified to return a better error message to the user when a Custom Expression has a circular reference
• (April 8, 2009) Made the branch fields for "Branch Device Type" and "Consolidate Branch" available regardless of whether the ITP add-on has been purchased
• (April 8, 2009) Added fields to show the "Number of" Breakers, Disconnects, and ZBRs in an Area, Zone, or Substation.
• (April 14, 2009) Adding back in the old "Legacy Tables" options for sending contingency violations and contingency definition data to Excel. This was available in earlier versions of Simulator but had recently been removed.
• (April 28, 2009) Added new option to the pop up menu for contingency records to Join Active Contingencies. This will create new contingencies that are the join of the current contingency list and a list read in from an auxiliary file. Only those contingencies not listed as being Skipped will be considered in the join.
• (May 1, 2009) Greatly enhanced the user interface for looking at "What Actually Occurred" in the contingency analysis results. When choosing this entry from the Combined Tables dropdown, you now see a list of what actually occurred under every contingency. There are also separate columns to query.
• (May 6, 2009) Added a new contingency element action type called "Open Breakers". When coupled with the ability to specify a branch as "Branch Device Type = Breaker", Simulator will dynamically determine a set of breakers to open either a Branch, Generator, Load, Switched Shunt, DC Line, Interface, Injection Group, or Three-Winding Transformer.
• (May 6, 2009) Added option with individual contingency records to ignore contingency specific solution options. This is intended mostly to ignore the options that are specified for all contingencies, but any solution options set for the specific contingency will also be ignored.
• (June 18, 2009) When looking at a list of contingency violations in a case information display and choosing Show Dialog, the dialog of the violated element (Branch, Bus, or Interface) is now shown.
• (July 9, 2009) Modified the Contingency Element Dialog so that you can search for objects using labels.
• (July 9, 2009) Modified the Contingency Element Dialog so that when search for Branch objects a drop-down appears that allows you to choose the Branch Device Type which you are looking for.
• (July 23, 2009) Added a new option to the Contingency Elements for Injection Group "Set To" or "Change By" actions to specify that the amount of generation change should be achieved by opening generators instead of changing their MW output. When the amount of change needed is negative generators will be opened until the amount opened exceeds to user-specified change.
• (August 10, 2009) The contingency element for setting or changing a injection group MW output by opening generators in merit order has been modified. Generators are now opened until a generator will exceed the desired total change. If a generator will exceed the desired amount it is not opened, but the remaining generators continue to be processed in merit order and are opened if the total change does not exceed the amount desired.
• (August 18, 2009) Added an option when saving the Contingency Analysis Auxiliary File to use DATA sections for objects such as Violations, Contingency Elements, Interface Elements, etc. instead of writing these objects inside of the SUBDATA sections.
• (October 23, 2009) modified the contingency action which changes or sets the MW Setpoint of a phase shifter so that it now automatically turns the phase shifter onto control. Previously if the phase-shifter was not already on control the setpoint would change but this wouldn't do anything because it wasn't on control.
• (February 15, 2010) The "Open with Breakers" algorithm was modified to allow buses with on-line generators to be traversed as long as no more than 10 such buses are encountered. If any load is traversed during the algorithm, then the statuses of the encountered on-line generators are set to OPEN along with the breakers found.
• (April 29, 2010) When looking for the post-contingency AUX file, Simulator looked in the current directory (which can change when opening files) or the file path specified with the post-contingency aux file if any. An extra check has been made so that if the file is not found in either of these locations, then Simulator will also look in the directory from which the present case (PWB, RAW, EPC, etc...) file was loaded.
• (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.
• (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.

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Fault Analysis

• (May 6, 2009) Changed default transformer configuration for fault analysis to ungrounded wye-wye instead of grounded wye-wye
• (December 30, 2009) Added a new object type Fault_Options allowing the change of fault options from an AUX file. The variable names are FAFaultCurDisplayAmps, FAIECPowerFactor, FAIECVolt, FAPreFaultProfile, FASetLineCharging, FASetShuntElements, and FASetTRRatio

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File Formats

• (April 8, 2009) When reading the GE and PTI files, the three-winding transformer magnetizing B and G values are now properly read into the three-winding transformer record. The two-winding equivalents were always properly created, this was only an issue with the three-winding data viewing.
• (April 10, 2009) Fixed an error which would cause the inability to read in a PWB file written using the April 9 patch. Note that any files for which you are seeing an error load the PWB file are NOT actually broken. The error was only in the LOADING of PWB files and this is now fixed in the April 10 patch.
• (April 14, 2009) Previously when loading an EPC file, only buses that had some online generation would set generator's AVR=NO in Simulator. This has been changed so that if there is no online generation, then the Mvar range for all offline generators is queried and all generators are set to AVR if the Mvar range is too small.
• (May 20, 2009) When reading RAW files, added additional error trapping when encountering a two character circuit or device identifier string which contained a single quote. The RAW file would contain the text [1,2,'2'',...] which does not conform with a CSV file that uses a single quote as a string encloser. To fix this, Simulator now looks for a string of text of the form '*'' and handles it appropriately.
• (May 27, 2009) Fixed the reading of MW Transactions tables from the EPC file format. These transactions were not being brought in from the EPC format.
• (May 27, 2009) Updating the reading of interface records from the "NERC Book of Flowgates" to support 12 character bus names and three-winding transformer elements.
• (June 4, 2009) Added the ability to Read and Write generator capability files in the PTI GCAP format.
• (August 18, 2009) Added the ability to renumber three-winding transformer star buses. The option is available on the Tools Ribbon under the Edit Mode Tools Renumber Menu. It is also available under the three-winding transformer's case information records menu. See the new Auxiliary File feature for more description on the renumbering file format.
• (August 24, 2009) When loading an EPC file, it is possible to run across two different three-winding transformers with identical star bus numbers. Simulator automatically corrects this data error by creating a new bus with an unused bus number and uses this as the star bus. An appropriate error message is written to the log.
• (October 13, 2009) When writing out the multi-terminal DC line converters to an EPC file, if the converter was on current control Simulator was writing a 0.0 value for the power schedule. Similarly if one power control, current schedule was written as 0.0. This has been changes so that the schedule which is not presently used is populated with the present current or power instead.
• (December 31, 2009) Added error messages when checking integer lookups while reading from the Areva CSV file format to better communicate any minor problems encountered.
• (January 12, 2010) Added population of the first CustomString field bus, gen, load, switched shunt, and branch objects when reading from the Areva CSV file format. This field contains the very short "ID" read from the CSV file which is not unique in general but appears to be unique inside of a single substation. This ID is very short and useful on oneline diagrams.
• (January 12, 2010) Added population of labels for substations, areas, and zones when reading from the Areva CSV file format.
• (January 21, 2010) Added support for reading and writing the RAW Version 32 file format.
• (February 5, 2010) Modified reading the Areva hdbexport format so that a LN record with a negative X value is not treated as a series cap if the LN record goes between two buses with different nominal kV values.
• (February 17, 2010) Added a YES/NO field for all GE EPC objects under the "EPC File" folder which shows "Flagged for Delete in EPC". This flag will only be set TRUE if the status is read as "-4" in the EPC file. PowerWorld would not use this flag, but a user can use the flag to create an advanced filter to choose devices to delete. This value will persist as PWB files are saved and loaded.
• (February 17, 2010) Added a field for all GE EPC objects under the "EPC File" folder which shows the "EPC Modification Status". This field will show either "None", "Created", or "Modified". This value will not be saved in any format and will be initialized to None when read from any non-EPC format. When an EPC file is ready as a case the value will be initialized to "Created". When appending a case using the EPC format, the value will be set to "Created" if a new object is created, and if an existing object is modified by appending, the value will be set to "Modified". Not object was never created by reading from the EPC file, this value will still be blank.
• (February 22, 2010) Modified the "EPC File" extra fields for three-winding transformer branches so that the secondary and tertiary windings show the "EPC File" information stored with the primary winding.
• (February 23, 2010) Modified log messages when reading EPC files with devices with status=-4.
• (March 4, 2010) Added a new option under the Save As menu in many case information displays called "Save As\GE EPC Format (only selected records)". This feature will generally save out the selected records as an EPC data section (for some object types there may be multiple sections).
• (May 13, 2010) Changed the label format for the labels assigned to objects when reading in a hdbexport case file. They now follow the convention $Substation$DeviceType$DeviceID. This matches what is used to generate the object identifiers for automatically generating aliases and alias subscriptions.
• (May 26, 2010) In an EPC file, if branches have the same From bus, To bus, circuit ID, and section number only one of the lines is retained.  These used to be made into sections of a multi-section line.  If any of the branches is marked for deletion (status = -4) then that branch is removed.  Otherwise, the last line encountered is kept and the other lines are removed.
• (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 9, 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.
• (October 6, 2010) When loading in EPC files and the latitude and longitude values are both zero, both entries will be ignored as invalid.

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General

• (April 8, 2009) Added a new Tool to browse the Case Description headers for all the PWB files in a single directory.
• (April 9, 2009) Added the ability to store in the Windows Registry whether the Ribbon is minimized and whether the Quick Access Toolbar is above or below the Ribbon. This will then be remembered the next time you open Simulator.
• (January 12, 2010) Added support for the name of a substation to be the secondary key field.
• (January 21, 2010) Added support throughout for switched shunt objects behaving as though they are owned by their terminal bus' owner. This affects the use Area/Zone/Owner filtering on switched shunt objects. Also added the ability to view the bus owner field of a switched shunt.

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Help

• None.

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Integrated Topology Processing (ITP)

• (March 23, 2009) When using the Consolidated Superbus View with the Integrated Topology Processing add-in, we now force the showing of circuit breaker symbols on branches, loads, generators, and switched shunts which are Open.
• (March 23, 2009) Added support for using Bus, Generator, Load, Switched Shunt, Area, and Zone filters on a Superbus or Subnet.
• (April 8, 2009) In some full-topology models, buses are modeled which has no load, no generation, no shunt, and have only one branch connected to them which is always out-of-service. These buses represent ground points. The Integrated Topology Processing has been modified to better integrate these into the solution without creating a large number of dead buses unnecessarily.
• (April 8, 2009) Fixed several issues in the Bus View when showing the "Consolidated Bus View" when parallel connections exist between super buses.
• (April 14, 2009) After loading in an AUX file, Simulator automatically calculates branch line MW and Mvar flows for all lines in the case. This has been modified so that if a branch has its flow values specified in the AUX file then the values are not left at the values read from the AUX file.
• (April 28, 2009) When running the PV Curve tool modified to not store system states when using the topology processing.
• (April 28, 2009) General Improvement in the Bus View showing the Consolidated Superbus.
• (May 6, 2009) Added a new contingency element action type called "Open Breakers". When coupled with the ability to specify a branch as "Branch Device Type = Breaker", Simulator will dynamically determine a set of breakers to open either a Branch, Generator, Load, Switched Shunt, DC Line, Interface, Injection Group, or Three-Winding Transformer.
• (May 20, 2009) Added support to the OPF and SCOPF add-ons to utilize the ITP features.
• (July 23, 2009) Added options to select only a single bus per super bus for PV/QV tracking and QV curve tracing. This is access through either a button click on the appropriate dialogs or through a new script command with no parameters call "PVQVTrackSingleBusPerSuperBus".
• (October 1, 2009) Added the ability on the oneline to right-click on a generator, load, switched shunt, transmission branch, or DC Line and choose to "Open Breakers to Isolate". Also added this option to these same objects in the case information displays. This option will then automatically traverse the system topology to locate a group breakers that when opened will isolate the selected device from all online generation.
• (December 21, 2009) Added ability to load a CSV file generated using the HDBExport command with an appropriate pattern file. This loads the entire EMS system model in as a case.
• (February 5, 2010) Modified several various GUI messages and Message Log when performing solutions using ITP. The messages were showing identifiers such as bus number based on the post-consolidated system instead of the full-topology model.
• (April 9, 2010) Added an optional parameter to the end of the SaveConsolidatedCase() script to specify the format of the contingency file if saving using the PTI format.

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Model Explorer

• (April 28, 2009) Modified the Filter Bar so that when you choose Find it automatically defaults the Filter By setting on the Filter Dialog to be the same as the Filter By choice on the Filter Bar.

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Oneline Diagrams

• (March 16, 2009) Greatly enhanced the speed of using the "Send to Back" and "Bring to Front" features of a large selection of displays object.
• (March 17, 2009) Added a substation shape option to the default drawing values.
• (April 8, 2009) Line Navigation Arrows are now drawn on top of all other objects such as pie charts or circuit breakers.
• (April 8, 2009) Changed the shape of the Line Flow Objects to match the shape of the animated flow arrows. An arrow shape is now used instead of a triangle.
• (May 6, 2009) Added the ability to specify a "Delta per Mouse Click" for the area field showing the flow to another area. Modifying this value will modify the MW Transaction between the two areas.
• (June 4, 2009) Added ability for the user to specify which objects to export to the KML file as well as which data fields.
• (July 23, 2009) Modified the drawing of Substation display objects to force them to have a size of at least 1 pixel. Normally as you zoom out, when objects become very small they completely disappear. Bus display objects and substation display objects are now the only exceptions to this which always draw at least a single pixel.
• (August 18, 2009) Added a Simulator Option under the Onelines Tab to "Automatically Show Full when opening any oneline". This option applies to all online diagrams when they are opened.
• (August 21, 2009) Modified the Line Flow Objects so to have an option to "Show Complex Flow (MW+jMvar)" values.
• (September 11, 2009) Modified the mouse wheel zooming so that it zooms in on the location of the mouse cursor. Previously it zoomed in on the center of the oneline only.
• (September 11, 2009) Modified zooming in and zooming out using the keyboard and mouse wheel so that if you go "in twice" and the "out twice" you end up at the same zoom level.
• (October 27, 2009) Modified the drawing of Line Flow Arrow objects to bias the drawing text to the left of arrows that are directly vertical. Previously arrows that were at exactly +90.0000 degrees and arrows at -90.000 degrees would have arrows drawn on opposite side of on another. Now arrows near +/- 90 degrees will be biased to draw to the left to make them consistent.
• (January 12, 2010) When right-clicking on a multi-section line display object a oneline diagram, access to the option "Show Long Line Voltage Profile" has been added. This applies to the bus view as well.
• (February 17, 2010) Modified the writing of an AXD file to support writing using labels as the identifiers for the oneline display objects.
• (March 18, 2010) Modified how intermediate points on transmission lines would move when dragging the buses to which the lines was anchored to behave more consistently.
• (May 26, 2010) Option of whether to draw transformer symbols as coils or circles can now be specified differently for each oneline diagram.  The option can be found on the Oneline Display Options dialog on the Display Object Options tab.  Setting the option to Default will use the Transformer Symbol option specified with PowerWorld Simulator Options (stored in the Windows Registry).
• (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.

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OPF Reserves Tool

• None.

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Optimal Power Flow (OPF)

• (October 23, 2009) Modified the PWLPTabRow object to allow script commands to obtain the LP Basis Matrix (using variable names LPBasisMatrix:X) and the full LP Tableau (using variable names OPFCNAin:X).

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Power Flow Solution

• (March 23, 2009) Changed the requirements for a viable island. Previously a 0 MW closed load was sufficient, but now islands must have closed load which is non-zero.
• (April 10, 2009) Improved transformer tap switching coordination in situations were a large number (> 50) transformers are trying to switch and a large number of those are stuck at the minimum or maximum tap or phase.
• (May 6, 2009) Modified so that generators set to any kind of Wind Power Control Mode will not be automatically chosen as a slack bus when Simulator dynamically chooses a slack bus.
• (June 25, 2009) When re-energizing an island by closing in a branch that connects the island to another energized island, Simulator estimates new voltages in the newly energized island before the power flow solution. A similar estimate has been added when energizing an island only by turning on generation in that island.
• (June 30, 2009) Added the ability for transformers to use line drop compensation to regulate a point an impedance away from the regulated bus of the transformer.
• (July 23, 2009) Augmented the new feature from the June 30 patch regarding setting transformers to use line drop compensation to regulate a point an impedance away from the regulated bus of the transformer. The impedance can now include both a resistance and a reactance.
• (September 29, 2009) Modified the angle smoothing routine in Simulator to handle the situation where two branches that were recently closed (or bypassed) are in series with one another (but with other lines in between them). Previously lines directly in series were properly handled as a group. Now the more general case with lines in series are handled as a group.
• (October 23, 2009) When model phase shifters as discrete controls, sometimes a phase shifter could get stuck one step away from its minimum or maximum phase shift. This has been fixed so that it can achieve the full minimum or maximum.
• (October 23, 2009) Implemented changes for keeping track of constant power, current, and impedance loads when using island based AGC with an injection group. Loads in the source and sink injection group will be adjusted to account for changes in voltage affecting the total load from the components. This is relevant for power flow, ATC, and PV.
• (March 18, 2010) Added a new Regulation Type for switched shunt objects which allow them to regulate the sum of their Mvar output with the Mvar summation of all generators with "Wind Control Mode = Constant Power Factor" marked to regulated the same regulated bus as the shunt.
• (March 19, 2010) Added a new Wind Control Mode for a generator called "Follow Min Mvar Capability Curve".  When on this mode, the Mvar output of the generator is always set equal to the value determined from the reactive capability curve's minimum Mvar value for the present MW output.
• (March 19, 2010) For switched shunts set to regulate "Wind Mvar", modified the control to ensure that the Mvar output is synchronized with the generator Mvar output prior to a power flow solution.  This helps with power flow convergence when modifying the Mvar output of these wind generation plants.
• (September 22, 2010, 4:30 PM) 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 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.

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PV and QV Curve (PVQV) Tool

• (March 16, 2009) Moved the option for setting the number of critical scenarios to find from the Results tab to the Common Options tab. It makes more sense here.
• (April 8, 2009) Added a check when running the PV Curve or the QV Curve tools to ensure that the Post-Contingency Auxiliary File exists. If the file is specified in the contingency analysis options but does not exist then the PV and QV curve will be aborted.
• (April 8, 2009) When writing out PV Results, we now write out 5 decimal points intead of 4.
• (June 18, 2009) Added the ability to specify that the PV Curve output file be written as the transpose. Previously each row of text represented a transfer level and columns were tracked values. When choosing the transpose, each row represents a tracked value and columns represent the transfer levels.
• (July 23, 2009) Added options to select only a single bus per super bus for PV/QV tracking and QV curve tracing. This is access through either a button click on the appropriate dialogs or through a new script command with no parameters call "PVQVTrackSingleBusPerSuperBus".
• (August 10, 2009) Added nominal kV along with bus name when displaying bus identifiers for selecting the values that should be plotted for PV or QV tracked quantities.
• (September 11, 2009) Added storage of the low and high voltage limit violations as a SUBDATA section of the PWPVResultListContainer object (the PV results).
• (September 21, 2009) The minimum step size for the PV Curve tool is now limited to 0.1 MW or greater.
• (September 21, 2009) The PV curve tool now strictly enforces a hierarchy for the various tolerances in the iteration processes. Tolerances are now adjusted according to following rules at the start of the PV process.
  (1) MVA convergence tolerance must be < (Minimum Step)/10.
  (2) Island based AGC tolerance must be < (Minimum Step)/2
  (3) MVA convergence tolerance must be < 0.2*(Island based AGC tolerance).
• (October 1, 2009) Fixed problem that would prevent the PV curve tool from executing if specifying an output file but not explicitly specifying the output directory. If the directory is not specified the current directory will be used.
• (October 16, 2009) When ramping injection groups in a PV curve trace, an AGC tolerance is used. This tolerance is related to how far the slack bus output can be from its desired output. A typical value is 2.0 MW. This worked correctly for a single PV curve step, but the tolerance was applied independently at each PV curve step, and thus the slack could under (or over) generator by 2.0 MW at every step. The error could then accumulate over the course of the dozens of steps used in the PV curve trace. This has been fixed so that the slack bus output error does not accumulate during the PV curve trace.
• (December 21, 2009) When writing values out to an AUX file for PV results, values below 0.001 are now written using scientific notation to ensure small values can be viewed properly.
• (December 21, 2009) Implemented option to track inadequate voltages with the PV tool, display them, and save/load from auxiliary file.
• (December 21, 2009) When saving PV states to a PWB or AUX file, turn off AGC for the entire case to avoid confusion when these cases are examined.
• (January 21, 2010) Add ability to use calculated fields with PV results.
• (January 21, 2010) ATC Extra Monitor values tracked with the PV results now have fields to show what the flow is at the transfer level at which the first inadequate voltage is encountered if choosing to store inadequate voltages.
• (March 30, 2010) When choosing to save all states and encountering critical scenarios, the base case state with the transfer implemented will be stored for all transfer levels that are solvable for critical scenarios before the final critical transfer level is found. Previously, states were only saved for the critical scenario itself.
• (May 18, 2010) Modified the text file which stores all the PV Curve tracking results and the QV Curve tracking results to always use a comma as a separator in the text file.
• (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.

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Security Constrained OPF (SCOPF) Tool

• None.

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Sensitivity Calculations

• None.

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Simulator Automation Server (SimAuto)

• (June 25, 2009) Added support for accessing the SCOPF contingency violations using SimAuto and Auxiliary File script commands.
• (July 2, 2009) Added the ability to obtain the SCOPF Contingency Violations for interfaces through the use of script commands and SimAuto
• (July 23, 2009) Added a new SimAuto function called "GetCaseHeader(filename)". By passing in a filename to the procedure, Simulator will extract the Case Header information from the file. The return value of the function will be of a format similar to other SimAuto command. Result(0) will an error string that is blank if no error occurs. Result(1) will be an array of strings containing the contents of the Case Header or Description of the PWB file.
• (August 24, 2009) Removed the message dialog which appears to notify a user that the Automation Server can not be registered. A message log entry is added instead.
• (September 29, 2009) Modified to objects CustomCaseInfoRow and CustomCaseInfo to automatically create a new object if one does not exist when modifying data for them.
• (October 23, 2009) Modified SimAuto so that registering and unregistering SimAuto doesn't require a new license key. This prevents the problem where when Simulator is elevated on Windows Vista and Windows 7.

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Time Step Simulation

• (May 1, 2009) Add the ability to specify the default TSB file without a directory. This makes it possible to just look in the current working directory for the TSB. Also fixed the Excel save options to work accordingly.
• (September 1, 2009) Adding button on the options tab to enable the user to reset the reference case to the the present case.
• (September 1, 2009) The number of contingent violations were not being reported properly on the time step simulation dialog when set to solve contingencies in Single Solution mode. The number of violations in the contingency analysis is now reported properly.
• (September 11, 2009) Added option to select if the post script command should be run before or after the results are stored. Default is after.
  (September 11, 2009) Saved some options to the TSB file that had been omitted.
• (October 1, 2009) When running a normal Single Solution power flow, any transaction costs associated with MW transactions are ignored. These transaction costs are only included in an Area's costs if the MW transaction is being dispatch by the OPF. A bug was occurring that caused these transactions to be included after solving a power flow solution, if an OPF had previously been run.
• (October 23, 2009) Changing the way schedules are applied to time points. Presently if the schedule does not contain a value at a time point and the interpolation is not enabled, then the value of the field in the case is returned. I have changed it so that the schedule is appies the last value in the schedule instead of the value in the case

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User Interface Dialogs

• (April 8, 2009) Added the ability to specify the Magnetizing B and G values on the transformer base on the Transformer Base Dialog.
• (April 8, 2009) When right-clicking on a three-winding transformer dialog in Run Mode and choosing show dialog, we now open the dialog related to the three-winding transformer data.
• (April 8, 2009) Added storage to the windows registry regarding the choice of "Sort by Number" or "Sort by Name" on the various object chooser dialogs. This will now be remembered between sessions.
• (June 4, 2009) Added a new feature to "Find Circulating Mvar and MW Flows" which will determine all the places in the power system model which have circulating flows. This is available under the Connections Menu on the Tools Ribbon tab.
• (June 18, 2009) Added a severity ranking to the new circulating Mvar and MW flows tool to rank cycles according to an estimate of how much Mvar or MW loss the cycle is creating.
• (July 9, 2009) Added support in the Difference flows for comparing the custom floats, custom integers, custom strings, and Memo fields for all objects.
• (July 9, 2009) Added support in the Difference Flows for showing the difference in the area or zone names and numbers
• (July 9, 2009) Added support in the Difference Flows for comparing ownership information allow you to see how the ownership of devices changes.
• (July 9, 2009) Added ability to access the lists of removed objects using script command. The object names all start with the string "Removed". For example RemovedBus, RemovedGen, etc...
• (July 9, 2009) Added a new field called "Difference Flows\In Diff. Flows Base Case?" for all the object types which store Difference Flows base case information. This field will be YES if this object is in the base case and NO if it is not.
• (July 27, 2009) Modified the Difference Flows feature to permit the comparison of cases using either labels or Secondary Key fields (Name/Nom kV) as the key field for the comparison.
• (August 10, 2009) When moving equipment by right-click on buses on the oneline diagram, the anchoring is not properly updated and deviced graphically moved to connect to their new buses as appropriate.
• (November 12, 2009) Added new feature to show the Long Line Voltage Profile across a transmission line. This is available by right-clicking on a transmission line on either a oneline diagram, bus view, or case information display. On the case info display you may select multiple branches and right-click to view the profile across all of the selected branches. This will show a graph with the per-unit voltage profile as the Y-Axis and the X-Axis will go from 0% (from bus) to 100% (to bus).
• (November 18, 2009) Added a similar Long Line Voltage Profile across a multi-section line as done in the 11/12/09 patch. Each line section is represented by a 100 range on the x-axis (e.g. the third section goes from 200% to 300%.) Also, a section representing a series cap or transformer will be represented by a dotted straight line.

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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
• Fault Analysis
• File Formats
• General
• 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
• User Interface Dialogs

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Auxiliary Files (SCRIPT and DATA Sections)

• (April 8, 2009) Added support for saving schedule subscriptions to aux files
• (April 8, 2009) When loading a case using the Auxiliary File, previously we would always recalculate the Line MW/Mvar flows after completing the load of the file. This has been modified so that if Line MW or Mvar values are read from the AUX file, then we do NOT recalculate them.
• (April 8, 2009) If transformer impedance correction tables were created using an auxiliary file after the transformers which used the tables were already created, then the link between the transformer and its table was not properly created. This has been fixed so that the order of creation does not matter.
• (May 1, 2009) Fixed error that could occur when looking up a Transformer object that did not exist.
• (July 2, 2009) Using the area/zone filtering option on the Auxiliary File Export Format Description was not working properly. This has been fixed.
• (August 21, 2009) When reading an AUX file, modified the generator GenMW field to ensure it is always read BEFORE the GenAGCAble field. This is done because when changing the GenMW field, Simulator by default sets the AGC status to NO. By reading the AGC status AFTER the GenMW field we ensure it is set to the desired setting.
• (September 29, 2009) Fixed problem when reading in the "Contour" object from an AXD file if the AXD file had been generated in Chinese.
• (September 29, 2009) Add ability to generate the contour immediately when loading an AXD file into the 2D mode.
• (November 2, 2009) When invoking the script command ExitProgram, Simulator was popping up a dialog box prompting the user to save the case. This has been fixed so that no dialog box is shown when calling ExitProgram.
• (December 21, 2009) When loading a case using the auxiliary file format, it was possible to create branch records which had the same key fields. We were only checking to see if an existing branch existed, so if the same branch were listed twice in the AUX file it could be created twice. This has been fixed.
• (February 5, 2010) Fixed error when writing out Model Expression or Model Condition information to an auxiliary file while using labels for devices which did not have a label.
• (July 23, 2010) Fixed access violation caused when calling MergeLineTerminals() with no branches actually meeting the filter. This will now simply do nothing instead.
• (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.

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Available Transfer Capability (ATC) Tool

• (April 28, 2009) When using the iterated steps in ATC and ramping of the base case state, if the power flow fails the step size is reduced by a factor of 2. After a successful solution the entire remaining desired step was attempted immediately. This has been changed so that the decreased step size is used instead until the desired step is achieve or the minimum step size is reached. This should speed up the ramping in bad situations.
• (May 20, 2009) Modified to prevent the ATC calculation from occurring when using iterated methods for a transfer between areas if one of the area's AGC is set to not on area control. An appropriate error message is shown asking the user to adjust the control method before continuing.
• (August 18, 2009) When loading in an auxiliary file, don't create ATCExtraMonitor unless the object being monitored exists. This was causing an access violation.
• (August 24, 2009) When showing the multi-scenario transfer limiter results, and then clicking outside of that window, the window would disappear behind the main program window. This has been fixed.
• (October 2, 2009) When using ATC multiple scenarios and showing the separate dialog with one particular scenarios result, this separate dialog could not be closed after it was opened. This has been fixed.
• (November 18, 2009) Fixed a problem which could occur when ramping a transfer causing it to ramp too far if power flow solutions were not successful at the initial transfer step. (Could be a problem for either in the positive or negative transfer amount).
• (February 5, 2010) Modified the ATC tool to properly utilize the new special contingency actions using Open with Breakers.
• (April 2, 2010) Modified how ATC results are filtered. For the single-linear step calculation, we now store the top limitations with each element and contingency according to the common options maximum lmiters per element and contingency. We then combine all limiters into a single table sorted by transfer MW limit, element, and contingency. We then process this list in order choosing the required number of results while enforcing the maximum mw limitation, number of elements, and number of contingencies. In previous version of Simulator 14 we only kept the limiters that were both limiting for the element and contingency. The new method will tend to report more results, especially when one contingency or one element had many transfer limiters.
• (June 3, 2010) Enabled the use of custom expressions with Branch Limiters (TransferLimiterBranch), Interface Limiters (TransferLimiterInterface), and Nomogram Interface Limiters (TransferLimiterNomogramInterface) tables with the ATC results.
• (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.
• (March 24, 2011) It was possible to get into an infinite loop during linear contingency analysis or linear ATC analysis due to generators participating in contingency make-up power hitting limits. This has been fixed.

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Bus View and Substation View Onelines

• (May 20, 2009) Custom views with spaces in the name could not be selected from the Views drop-down. This has been fixed.
• (May 13, 2010) Fixed a situation in which a parallel circuit that is parallel to another single circuit and several branches in series may not have the bus connection properly drawn for the To bus.

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Case Information Displays

• (April 8, 2009) For interface elements and participation points of injection groups, the "Selected?" field was not working properly. This field now properly only returns the selected field of the underlying object (generator, branch, etc...) to which the element refers.
• (April 9, 2009) The drop-down button on Case Information toolbar which shows a list of available filters was broken in the patch released yesterday. This has been fixed. This only effected that button and access to filters via right-click or the Filterbar was unaffected.
• (May 27, 2009) The short-cut keys on case information displays did not always activate as appropriate. This has been fixed. This effected the Ctrl+F (find), Ctrl+C (copy selection), and Ctrl+V (paste) shortcuts.
• (July 9, 2009) Modified the branch case information displays which show only those of a particular Branch Device Type so that the Find... feature of the case information display limits the branches by Branch Device Type.
• (August 21, 2009) When copying from Excel, modified the generator GenMW field to ensure it is always read BEFORE the GenAGCAble field. This is done because when changing the GenMW field, Simulator by default sets the AGC status to NO. By reading the AGC status AFTER the GenMW field we ensure it is set to the desired setting.
• (August 24, 2009) When clicking in the Upper-Left corner cell of a case information display, all sorting is supposed to be removed from the display. For matrix displays which show the same value for different objects in the columns, such as in Time Step Simulation, the sorting was not being removed. This has been fixed.
• (August 24, 2009) Fixed error with using advanced column sorting on matrix displays.
• (August 24, 2009) When using a 3-winding transformer field as part of a calculated field and then applying this calculated field to a bus object, the 3-winding transformer were counted double at the internal star bus objects. This has been fixed.
• (October 8, 2009) Allow series capacitor branch types to be changed through the Branch Device Type field.
• (October 13, 2009) When on a Bus case information display, the editing of the SUBSTATION latitude/longitude fields was not working properly (it would edit the bus fields instead). This has been fixed.
• (February 5, 2010) When copying an extremely large amount of text to the clipboard the interaction with Simulator's case information displays could become very slow. This has been fixed.
• (February 5, 2010) Fixed the use of Toggle all YES or Toggle all NO for the switched shunt fields related to Use Continuous Element, All or Nothing, Use Target High, or Switch in Inner Power Flow loop.
• (February 8, 2010) The 2/5/2010 patch included a bug which made all pasting into case information displays quit working.  This has been fixed in the 2/8/2010 patch.
• (February 22, 2010) Fixed a bug that could incorrectly applicate apply an advanced filters which "uses another filter" if several advanced filters had the same name. Advanced Filter names need only be unique for a particular object type, but this bug occurred when filter names were the same across different object types.
• (March 30, 2010) The use of Calculated Fields as applied to an owner object was not working properly and yielding strange results. This has been fixed. This error would also affect using non-owner advanced filters with an owner object.
• (March 31, 2010) Added back in support for custom expressions to use the following commands. This had been inadvertently removed. (Exp2,Log2,Exp10,Log10,ASin,ACos,Sec,Csc,Cot,SinH,CosH,TanH,CotH,SecH,CscH,ASinH,ACosH,ATanH,ACotH,ASecH,ACscH)
• (March 31, 2010) Loading of user defined case information displays back in from a PWB file was not working properly. This has been fixed.
• (March 31, 2010) Fixed bug Owner records which prevented all appropriate calculated fields form begin available for use.

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Contingency Analysis

• (March 16, 2009) Fixed access violation that could occur when pasting or loading an AUX file with unlinked elements for monitoring by exception.
• (March 17, 2009) When opening the contingency analysis dialog a dialog appears asking you whether you would like to set the present case as the contingency reference state. Regardless of what options were chosen on this dialog, Simulator was not setting the reference and the user would need to manually choose "Set as Reference" from the the Other button drop-down. This has been fixed.
• (March 23, 2009) When using the DC approximation (the DC Power Flow) with contingency analysis, the advanced contingency monitoring options were not being used. They are now included.
• (April 8, 2009) Fixed errors with modeling Bus Outages which create islanded load and generation using the Linearized Contingency Analysis methods.
• (April 28, 2009) Fixed nuisance access violation that occured on the Lines/Buses/Tranformers tab of the contingency analysis form when toggling the Selected or Skip field on the list of related contingency violations for each branch, interface or bus.
• (May 6, 2009) When showing the "Present Value" for Interface MW Violations in contingency analysis, the values were displayed in per unit. This has been changed so values are displayed in MW instead.
• (May 20, 2009) Fixed "can't make visible form modal" error when showing the make up power dialog for a particular contingency element.
• (May 27, 2009) The numeric fields shown for contingency records did not work properly when using the a custom expression. This has been fixed.
• (July 9, 2009) When showning the substation information for a limit violation on a branch, an error would occur if the branch's terminal buses did not belong to a substation. This has been fixed.
• (July 23, 2009) Fixed error when re-opening the contingency element dialog for a contingency action involving a Generator, Load or Shunt Set To or Change By action. When re-opening the dialog the object would not be properly chosen.
• (September 1, 2009) An access violation could occur when editing a contingency list while having the All Contingency Violations Table open. This has been fixed.
• (September 11, 2009) When using Solve Single Contingency in the DC power flow mode, the displayed results will reflect the correct generation dispatch due to any make-up power adjustments.
• (September 11, 2009) For Linear calculation methods, any generators that are impacted by a contingency will not be allowed to participate in the make-up power.
• (October 8, 2009) All model conditions and filters are now written out with contingency options.
• (October 15, 2009) When using the "Open With Breakers" contingency element on a Bus object, an access violation would occur. This has been fixed.
• (October 27, 2009) Mistake was made in the 10/23/09 patch regarding the new feature to turn on transformer control when defining a contingency element which changes the MW setpoint. This has been fixed.
• (December 21, 2009) When using the DC approximation and running the contingency analysis, regardless of Limit Monitoring Settings or other settings related to amp flow, the flows and limits will be based on MVA/MW.
• (January 12, 2010) In a bug fix added on 12/21/09 regarding ensuring that amp limits are not used when using the DC approximation, a bug was introduced related to monitoring of CHANGE violations or changes from a basecase violation.  If monitoring for change violations, this bug could cause inconsistent AC contingency results because the initial flows on monitored branches could be recorded in amps when they should be recorded in MVA or recorded in MVA when they should be recorded in amps. This would cause a problem when comparing the flows on branches post-contingency to their pre-contingency flows. This would not have been a problem if using the dc approximation when solving the power flow.
• (January 12, 2010) Fixed potential access violation which may occur after performing "Join Active Contingencies..." on your active list of contingencies and a list of contingencies in an AUX file. The access violation would be while running the Contingency solutions. After saving the case or AUX file list of contingencies and then reopening them, this error would have not reappeared. Regardless it is fixed in this patch.
• (February 5, 2010) Modified the contingency analysis to better handle situations where a contingencies contains several elements using the Open with Breakers feature. Add ability to better identify which breakers are needed to isolate which devices when a particular breaker may be needed to isolate more than one device.
• (February 17, 2010) The use of Monitoring Exceptions to Include the monitoring of an element was not working in conjunction with the linearized AC contingency solutions. It worked correctly with either the full AC solution or the DC approximation. It now works correctly in all situations.
• (March 9, 2010) Fixed potential access violation when using the Convert to Device Contingencies options.
• (April 30, 2010) Fix a highly unusual situation in which an unsolved contingency was immediately followed by another contingency which isolated only part of a multi-terminal DC line. This combination of events would cause an access violation.
• (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.
• (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) It was possible to get into an infinite loop during linear contingency analysis or linear ATC analysis due to generators participating in contingency make-up power hitting limits. This has been fixed.

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Fault Analysis

• (December 21, 2009) Modified editing of the internal generator impedance so that writing these impedances back out to a PTI raw files is done correctly.
• (December 22, 2009) Fixed handling of line-to-line fault calculation when a fault impedance value is specified. Previously the fault impedance value was always assumed to be zero regardless of user input.
• (June 22, 2010) Fixed error with the handling of out-of-service switched shunt when using the IEC-909 fault calculation.

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File Formats

• (March 17, 2009) Fixed an error with closing a PWB file if it contained a switched shunt record that had originally been read from the FACTS Device section of a PTI RAW file. This most commonly occurred with ERCOT cases at bus 9025.
• (May 1, 2009) When loading in an EPC file, when Simulator encountered any status values that were not appropriate no error message was generated and the device behaved incorrectly. This was first noticed with a case that had a branch status of -4. To correct this, and status which is not 0, 1, (or 2 for branches) will always be treated as closed and a log message will appear stating this.
• (May 1, 2009) When reading a RAW file, modified to assume a status of CLOSED for any entry in a RAW file with a status that is not 0 or 1.
• (June 25, 2009) Fixed error in reading in the load records of RAW version 31 files.
• (August 10, 2009) Fixed an access violation that could occur when writing out a RAW file if the name of the limit group "Default" was changed.
• (August 10, 2009) Fixed an access violation that could occur when writing out a RAW file if a switched shunt that was modeling a FACTS device was out of service.
• (September 21, 2009) Modified the reading and writing of EPC files to allow 12 character bus names.
• (September 21, 2009) Modified the writing out of EPC files to correctly write out an individual converter status. Previously if the entire multi-terminal DC was in service, but one converter was open it would still write out the converter as closed to the EPC file.
• (November 12, 2009) Fixed up the loadng of a PTI *.drw file. Bus objects were not being properly draw. Generator and load fields were not being properly read in. Also, it has been modified to skip "TT...EN" records in the file. Previously it would abort reading when encountering a TT record.
• (November 18, 2009) Fixed potential error which could occur when loading in a PWB file containing unlinked interface elements.
• (December 30, 2009) Fixed potential access violation if Areva EMS CSV file had an LN record referring to a LNLIM record which did not exist.
• (February 5, 2010) When reading a branch record in the GE EPC file, Simulator was not handling the the ohmic flag, and thus the R, X, and B value could be read incorrectly if the ohmic value was 1. This has been fixed.
• (February 17, 2010) Fixed error when reading RAW version 31 or 32 formats which omitted optional parameters at the end of the FACTS records.
• (February 22, 2010) Fixed bug that could occur when appending an EPC file containing three-winding transformers
• (February 22, 2010) Fixed error when appending multi-section transmission line using an EPC file. When appending, Simulator will now look for the multi-section line record, and if one is found data will be appended to the appropriate section.
• (March 9, 2010) Modified the reading of EPC files to properly show the modifications status of Interfaces and Interface Branches after appending an EPC file to a case.
• (March 18, 2010) When loading an EPC file, modified bus objects to be labeled as "Flagged for deletion by EPC" when a bus type of -4 was read.
• (March 18, 2010) When saving out an EPC file, fixed a potential problem with writing out the incorrect section number of some branches of multi-section lines.
• (March 30, 2010) After loading an EPC file and populate the GE EPC fields for load records, Simulator was not properly saving this information to the PWB file format. As a result the GE EPC fields for Load records was lost. This has been fixed.
• (April 6, 2010) When appending a case using PTI RAW or GE EPC files, Simulator was not replacing the existing ownership information of and object and was instead just appending to the existing ownership. This has been modified so that when appending to an objet all existing ownership information for that object is removed and replaced with what is in the RAW or EPC file.
• (April 6, 2010) When reading the EPC ownership records and retaining the extra EPC fields, an extra colon character (:) was not properly accounted for making the read of the extra EPC fields incorrect. This has been fixed.
• (April 6, 2010) Added ability to see EPC fields for ownership records. This had previously been omitted.
• (April 6, 2010) An error existed when reading an EPC file which contained a comment line (starting with #) that also included a slash character (/). The error resulted in Simulator skipping the line of text after the slash character. This has been fixed.
• (April 13, 2010) Fixed an access violation that occurred when reading in the Areva EMS *.csv file format.
• (April 13, 2010) Added proper error checking when writing out the DateIn and DateOut fields to an EPC file to ensure only integers are written out. Previously an error could occur when writing out the EPC record.
• (June 8, 2010) Fixed reading .CON files to also allow the key words LINE or BRANCH when reading three winding transformer contingencies.
• (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 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 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 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.
• (September 22, 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.

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General

• (August 21, 2009) When simultaneously executing multiple PowerWorld Simulator instances, it was possible for an error dialog to appear saying "Unable to save the license information. Please try again with administrator privileges". This error dialog was not caused by privileges but instead by the multiple Simulator trying to write to the same location simultaneously. This error dialog has been removed.
• (August 24, 2009) Fixed an error message and resulting license failure which could occur when multiple instances of Simulator were executed simultaneously.
• (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 14, 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.

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Memory

• (March 16, 2009) When deleting a multi-terminal DC line record (whether manually, through a script, or through equivalencing), a memory access violation was occurring which corrupted the case. This has been fixed.
• (March 23, 2009) A possible error could occur when opening the Model Explorer. This only occurred if a new PWB file had been opened after creating User Defined Case information Display. This has been fixed.
• (June 18, 2009) Fixed a rare access violation that sometimes occurs when opening or closing a case.
• (August 18, 2009) When deleting a bus, added checks to make sure that any gen that is remotely regulating that bus is set off AVR and set to regulate its own terminal. Otherwise access violations could occur.
• (November 12, 2009) When deleting bus records that were connected to a multi-terminal DC converter, the memory link from the MTDC Converter to the bus was not properly cleaned up which resulted in an access violation. This has been fixed.
• (November 18, 2009) Fixed bug introduced by the memory fix in 11/12/09 patch which resulted in ALL multi-terminal DC line records being deleted when ANY bus was deleted.

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Integrated Topology Processing (ITP)

• (May 20, 2009) Buses which have no generation, load, or shunts connected to the system through a single open branch are treated as part of the Superbus of the bus to which they are connected. This greatly reduced the number of Superbuses in systems that model earth grounding disconnectors. This patch prevents these disconnected buses from being chosen as the primary bus of the superbus which resulted in solution problems.
• (October 8, 2009) Fixed equivalencing to work on a full-topology model in conjunction with integrated topology processing.
• (October 8, 2009) Corrected bug when saving consolidated case with the option selected to convert multiple switched shunts at a bus to a single shunt with multiple blocks. The nominal shunt value was not being set correctly and an access violation could occur if the shunts contained more than 10 total blocks.
• (March 4, 2010) When using Integrated Topology Processing, the reference state was not always handled properly.
• (March 4, 2010) Fixed an odd bug that occurred if (1) using the Open with Breakers contingency events and (2) using integrated topology processing. When opening the contingency dialog and choosing to "Set the contingency analysis reference state to the current case", the element statuses would not be reflected in the new reference state. If manually choosing to "Set as Reference" this was not a problem, but if simply running the contingency analysis immediately the element states would be reset to original reference state values.
• (May 18, 2010) Fixed a rare solution failure that could be occur when using the integrated topology processing in a case with an out-of-service phase shifter connected radially to one inservice bus and another dead bus.
• (August 30, 2010) When doing contingency analysis while using advanced limit monitoring settings and also using Integrated Topology Processing, the initial base case values associated with consolidated buses were not being stored correctly resulting in limit violations not being correct.
• (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.
• (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.

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Model Explorer

• (April 8, 2009) Fixed some errors with how the User Defined Case Information displays were managed after you opened a different case.
• (April 5, 2011) Fixed random access violations that could occur when using the Model Explorer.

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Oneline Diagrams

• (April 8, 2009) When drawing three-winding transformer objects, removed the drawing of a background color underneath the symbol.
• (April 8, 2009) On the Pan/Zoom dialog, the checkbox for "Allow auto updating on selection" was not visible by default. It is now.
• (April 8, 2009) When using the thumbnail view, the Line Navigation Arrows were not working properly. This has been fixed.
• (April 8, 2009) On old video cards which do not support OpenGL, the new faster contouring algorithm was causing an error which caused Simulator fail. This has been fixed to just default to the older contouring routine.
• (April 8, 2009) Switching to the 3D view on older video cards which do not support OpenGL could cause Simulator to fail. This is now captured and the switch to 3D is not allowed while an appropriate error message is shown.
• (April 14, 2009) When adding an interface field to a oneline diagram on which no interface display objects are drawn a nuisance access violation would occur. This has been fixed.
• (April 28, 2009) Added the right-click option to open the Area Information dialog from the oneline diagram.
• (August 18, 2009) When opening a oneline diagram as an AXD file and specifying that it open directly into the 3D mode, some of the text was not appearing. This has been fixed.
• (August 18, 2009) Changed the default digits when saving an AXD file for the "Stack" object so that more digits are kept.
• (August 21, 2009) When using the 3D oneline, little more offset was added between the contour image and the oneline diagram objects to ensure that the text fields appear on top of the contour image.
• (August 21, 2009) Added check to prevent error when closing a oneline diagram in 3D mode while showing a contour.
• (August 21, 2009) Modified to highlight unlinked three-winding transformer objects.
• (August 21, 2009) When renumbering a oneline diagraming, added support for renumbering the three-winding transformer objects.
• (August 24, 2009) In 3D mode, lines that were open were always drawn as dashed lines. This has been fixed.
• (September 1, 2009) Fixed the new three-winding transformer object so that it is properly renumbered when using bus renumbering.
• (September 1, 2009) Modified Generic Model Field display objects to properly appear as unlinked when appropriate.
• (September 1, 2009) All out-of-service lines were appearing as dashed when in 3D mode. They now only appear dashed in the appropriate Oneline Display option is chosen.
• (September 1, 2009) If loading an AXD file and immediately entering 3D mode, some text sizes were not properly updated and text either too small or too large. This has been fixed.
• (September 1, 2009) If loading an AXD file and immediately entering 3D mode, the option to show the contour image immediately was not working properly. This has been fixed.
• (September 30, 2009) The September 29 patch introduced a bug that did not allow oneline objects to be dragged.  This has been fixed.
• (October 2, 2009) When showing flow arrows and not choosing to scale the size of the arrow proportional to the flow amount, arrows could appear on branches, loads, generators, or switched shunts that were Closed but not connected to an energized bus. This has been fixed.
• (December 21, 2009) If a oneline associated with a PWB file is maximized when the PWB is saved, the oneline will open maximized when the PWB is opened. Fixed bug that would not properly maximize onelines if they are opened while other forms are maximized.
• (February 5, 2010) Fixed potential error with viewing 3D onelines with a GPU accelerated contour in Full Screen Mode.
• (March 30, 2010) When saving a case using the file type PWB with Options, the PWB file was saved appropriately, but if any diagrams were open they were saved in Version 14 format regardless. This has been fixed so that the PWD version is synchronized the PWB version.
• (March 31, 2010) When saving an AXD file, substation objects and substation fields did not properly save their substation name or number. This made loading the AXD file back in not properly load the substations.
• (May 13, 2010) When selecting the options to show circuit breakers for generators, loads, or switched shunts, only closed circuit breakers will be affected by this option. Open circuit breakers (indicating that Status = open) will always be shown regardless of this option setting.
• (July 2, 2010) Fixed flashing hint windows caused by interaction between navigation arrows and oneline hints.
• (July 2, 2010) Fixed error with contour dynamic value interpretation from June 25 patch.
• (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.
• (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 10, 2010) Fixed error on the Find Oneline Objects dialog when tyring to define a filter for the list of objects.

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OPF Reserves Tool

• None.

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Optimal Power Flow (OPF)

• (October 13, 2009) When calculating an area's cost including MW Transaction costs, Simulator was treating the cost of the transaction to be equal to the price at which the transaction was dispatched multiplied by the amount of the transaction. This was incorrect, the cost is now calculated as the integral under the transaction cost curve.
• (October 13, 2009) When calculating an area's cost including MW Transaction costs, only areas that were on OPF control were including the MW transactions costs. This has been changed so that all areas include the MW transaction costs.
• (December 22, 2009) New feature from the October 23 patch related to writing out LP Tableau and LP Basis Matrix was not fully functional and has now been fixed.
• (February 5, 2010) When setting up a case with multiple islands which had OPF areas on AND displatchable DC lines connecting the islands with dispatchable MW transaction between areas in the different islands, the OPF was not solving correctly. This has been fixed by adding a new constraint in this special situation for an island to ensure that the sum of DC flows out of an island was equal to the sum of area MW transactions out of the island.
• (February 23, 2010) Adding the new constraint for island MW controls in patch for Feb. 5, 2010, inadvertently causes the loading of OPF results from older PWB files to work incorrectly. This has been fixed.

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Power Flow Solution

• (April 28, 2009) Fixed more minor errors related to ensuring that transformer taps do not get stuck at their limits.
• (May 1, 2009) When all DC converters in a multi-terminal DC line had power or current setpoints of zero, Simulator would generate a log message saying there were no rectifiers or inverters found. The solution was fine but the log message was confusing and has been removed.
• (May 6, 2009) Modified so that generators at a slack bus that are also flags on a Wind Power Control Mode will properly behave as slack buses. Generally this should not be done, but Simulator will not at least handle this situation.
• (July 27, 2009) Fixed a bug that would cause a bus not to properly reenergize itself after being taken out of service in some situations.
• (September 11, 2009) Fixed an error which could occur in the multi-terminal DC line solution if converter current ratings would be hit with all converter CLOSED, but one of the converters was presently OPEN. This could result in the converter setpoints being reduced even when it was not necessary.
• (September 29, 2009) Simulator was allowing a generator's MW limits to be ignored when running the economic dispatch (ED) control on an area. This can results in unreasonable results (one generator at a huge positive output and another at a huge negative output). The ED has been fixed to not allow generator limits to be ignored.
• (September 29, 2009) When using DC power flow and solving contingencies or using linearized ac method for solving contingencies, generator MW limits will be enforced if choosing to do that and max post-contingency response for generators will be enforced if also choosing to enforce MW limits.
• (October 8, 2009) Fixed problem when using island-based AGC with an injection group that included constant current and/or constant impedance load components instead of all constant power. The resulting change for the load was not being accounted for correctly resulting in the possibility that a significant portion of the change would go to the system slack instead of the injection group.
• (October 15, 2009) If a phase shifter is in-service, but removing the phase shifter will split this system into two islands, then that phase-shifter can not regulate the flow on itself. Trying to do so in the DC power flow resulted in oscillating behavior. Previously, a nearby look was done to see if this was the case. Some cases were more complicated though, so a generic routine has been added to prevent these phase shifters from regulating.
• (November 2, 2009) When performing tap balancing on parallel transformers which have different transformer step sizes, some situations occurred which resulted in oscillating transformer taps and a failed power flow solution. This has been fixed.
• (December 2, 2009) Fixed an extremely rare situation that could cause solution trouble if multiple generators at the same bus had very small Mvar ranges.
• (May 13, 2010) Fixed error with automatically picking the slack bus. It was always picking the largest unit even though there is other logic that should have been used to pick the bus. For more details about how the slack bus is actually picked see the Simulator online help.
• (June 8, 2010) Fixed a bug with transformers where under rare circumstances a transformer's sensitivity was not being reset in situations when the user chose to reset the load flow to a stored reference state. The bug was causing such a transformer's regulation capability to be suppressed in solution attempts following the reference state restoration.
• (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 4, 2010) In the DC Power flow solution, added better handling of phase shifter switching to help with convergence.
• (August 30, 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 27, 2010) Fixed access violation that could occur when an AC bus terminal of a multi-terminal DC line was outaged.

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PV and QV Curve (PVQV) Tool

• (May 20, 2009) The PV Curve dialog did not properly maximize. This has been fixed.
• (May 27, 2009) Before starting the PV analysis, make sure that the directory to which the output file should be written exists. If the output file should be saved. If the directory does not exist, it will be created. If for some reason it cannot be created, the PV analysis will not run.
• (June 18, 2009) Fixed potential error that could be encountered when doing the reverse PV transfer. This was caused by improper coordination of tolerance levels.
• (July 23, 2009) When using the Integrated Topology Processing in conjunction with the PV curve tracing it was possible that the PV curve would abort prematurely due to a bus becoming disconnected. This has been fixed.
• (November 18, 2009) The checkbox on the QV curve Options, for saving results to a file was not working properly.  This has been fixed.
• (January 21, 2010) Fixed an access violation that could occur when doing reverse transfer and the first transfer step did not solve in the base case.
• (February 5, 2010) Modified the PV tool to properly utilize the new special contingency actions using Open with Breakers.
• (February 5, 2010) Modified the QV tool to properly utilize the new special contingency actions using Open with Breakers.
• (February 15, 2010) Changed PV analysis to perform consolidation when restoring the initial state or rerunning PV analysis if the case was initially consolidated before the first PV run.
• (June 22, 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.
• (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.
• (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.

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Security Constrained OPF (SCOPF) Tool

• (May 20, 2009) Fixed an error in the sensitivity calculations for generators connected to the system through parallel radial lines if a contingency was defined which outaged ONE of the lines. The generators were being treated as having zero sensitivity on the branch which remained in sensitivity and thus the overload could not be removed. This has been fixed.
• (February 5, 2010) Modified the SCOPF tool to properly utilize the new special contingency actions using Open with Breakers.

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Sensitivity Calculations

• (April 28, 2009) Fixed the "Set Sensitivities of out-of-service buses to nearest" button so that it properly refreshes the results grid after being clicked.
• (December 21, 2009) When calculating voltage sensitivities to a transfer, switched shunts that are on continuous control and located at buses participating in the transfer can be set to fixed by using the option that also turns generators at these buses off AVR control.
• (November 17, 2010) 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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Simulator Automation Server (SimAuto)

• (January 6, 2012) Fixed bug with SaveCase SimAuto function that would not allow the filetype to be specified.

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Time Step Simulation

• (April 8, 2009) When editing data directly in the case information display for time point load, generation, etc... values, after hitting the ENTER key the values were not be applied. This has been fixed.
• (April 28, 2009) Corrected bug that prevented some transformer fields to be shown in the subscription field list
• (May 20, 2009) Modified the export of schedules to AUX files so the decimal points are not fixed to 4.
• (October 15, 2009) Fixed an error when saving a TSB file if any of the schedules have no schedule points.
• (October 16, 2009) Fixed a memory leak that occurred when applying schedule subscriptions at each time point. The memory leak was small, but was proportional to the number of schedule subscriptions and would occur at every time point. Thus if you had a large number of schedule subscriptions and a large number of time points the memory leak became large.
• (February 22, 2010) Cleaned up some flickering issues when animating a oneline diagram in the time step simulation which contained a contour image.
• (March 30, 2010) Added the ability to paste from Excel (and read from an AUX file) the Skip and Solution Type columns for the Time Step Simulation time point records.
• (March 30, 2010) When plotting data in the Time Step Simulation versus time, the plotting routines were truncating the time variable so that it was only accurate to 5 minutes intervals. As a result, the plotting of data if time steps were less than 5 minutes was not working properly. This has been fixed.

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User Interface Dialogs

• (April 8, 2009) Modified the equations on the dialog for specifying transformer impedances on the transformer base. The shunt terms are not effected by the fixed taps or nominal kV values.
• (April 8, 2009) When opening dialogs as maximized, the new feature in Simulator 14 which stores the location and size of dialogs was still being applied. For a maximized form this should not occur and has been fixed.
• (April 28, 2009) Modifed the scaling of loads to ensure that generators do not also scale if the generator scaling is set to 1.000. Previously if you were enforcing generator MW limits in the scaling, Simulator would automatically bring generator up/down to their limits and then scale other generators appropriately so the net generation change was zero.
• (April 28, 2009) Modified the Browse Folder Dialog to use the newer Vista style of browse folder dialog if available. This includes a place to paste a path in as well.
• (May 20, 2009) Fixed "out of memory" error caused when trying to scale by bus and scaling generation as well as load.
• (July 23, 2009) Cleaned up some issues with fields not being filled in correctly when opening the Calculated Fields dialog with an already existing calculated field.
• (July 23, 2009) Fixed potential error on the TLR dialog when re-opening the dialog after previously selecting a branch using labels.
• (July 23, 2009) On the switched shunt dialog, when changing the bus or ID of an existing shunt, user is now prompted if a new shunt should be created or the existing one should be moved instead of just creating a new shunt. This makes the shunts more consistent with how loads are handled.
• (August 10, 2009) When using the Move Equipment Dialog, the ID of switched shunts was not being maintained if the shunt was moved to a bus that already had shunts at it. This has been fixed so that as long as the ID remains unique it is maintained.
• (September 29, 2009) The tap transmission line dialog would not allow a new bus number with more than 5 digits. This then resulted in the user accidentally choosing a bus number of zero which caused an invalid power flow model to be created. This has been fixed.
• (September 29, 2009) When using the choosing dialog to choose a multi-section line object, the circuit ID was not displayed in the Far bus list. This has been fixed.
• (October 2, 2009) When using the system menu to change a dialog from Container Mode to Free-Floating modes (or vice versa), some edit boxes showing integer values could be reset to 1. This would only occur immediately after changing modes. This has been fixed.
• (October 16, 2009) On the Run Mode multi-section line dialog, saving of information on the Custom tab was not working. This has been fixed.
• (October 16, 2009) Fixed an access violation that could occur when loading an Auxiliary file which switched into Edit Mode multiple times, while at the same time having open a dialog (such as Time Step or Contingency Analysis) which is not allowed during Edit Mode.
• (November 2, 2009) Fixed access violation which could occur on the Dynamic Formatting Dialog for a specific oneline diagram when invoking the advanced filter dialog.
• (November 12, 2009) When using the equivalencing dialog and choosing to save the external system as a PWB file, previously an error could occur when loading the PWB file back in if the external system did not include all three-winding transformer. This has been fixed so that old PWB files written this way will properly load.
• (November 12, 2009) When using the equivalencing dialog, added the ability to properly save the external system as an EPC file. Previously it would always just save the entire EPC file.
• (January 21, 2010) Fixed bug that would cause data entry problems in some special grids on user interface dialogs. Selecting a field for entry would not immediately allow you to enter data. You would have to double enter the first character to get the correct entry. Among affected grids are the MVA limits grid on branch dialogs, the reactive capability curve grid on generator dialogs, and the switched shunt block grid on switched shunt dialogs. This did NOT affect any grids in the Model Explorer.
• (March 4, 2010) When opening the bus dialog by right-clicking on a bus oneline object and choosing show dialog, it was possible to inadvertently relink the bus oneline object by navigating to a new bus. Linking the oneline object to a different bus should only be possible by clicking on the Link to New Bus button.
• (March 9, 2010) Fixed potential access violation when adding a bus object to a oneline diagram.
• (March 18, 2010) Fixed a problem with setting the current path when opening a case in Windows Vista and Windows 7.0. This could impact the automatic opening of TSB files and Auxiliary files when opening a case.
• (March 18, 2010) Fixed potential access violation that could occur when saving a oneline diagram which contained many model field and text objects.
• (June 8, 2010) Fixed the Bus View menu item in the lines table pop up menu on the Owner dialog.
• (July 9, 2010) Fixed error in feature to remove additional GE EPC data from the case.
• (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.

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