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Simulator Version 12.0 Patch Description


What's in the Simulator 12.0 Patch?


Use the link above to get email updates when the patch changes
PowerWorld Simulator 12.0 Patch addresses problems found in Simulator 12.0 following its official release in June 2006.  New features are also added via the patch as appropriate. You can view patch descriptions by date or view summary descriptions of New Features/Minor Improvements or Bug Fixes by selecting the appropriate links.

This patch was first introduced on June 26, 2006.

The patch was last modified February 6, 2008.

Click here to go to the patch download page.

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

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June 26, 2006

New Features

  • Auxiliary Files: Modified the Simulator-created auxiliary files for contingency settings, limit monitoring settings, etc... so that when they using the SelectAll() script commands they are followed later by UnselectAll() commands, so that in the end all objects are not selected.
  • Case Information Displays: Added fields to the transmission branch Display/Column options to show the MW Marginal Cost at the From and To Bus.
  • Oneline Diagrams: Modified Measure Lines so that when showing Oneline hints, the measure line will always show a hint with the length of the line.
  • Oneline Diagrams: Modified so that if a PWD file is marked as read-only, then Simulator will not prompt the user to save the oneline.
  • User Interface Dialogs: added Max MW, Min MW, and AGC status fields to the columns on the Line Loading Replicator dialog.
  • User Interface Dialogs: Added a keyboard shortcut on the choose dialogs which list devices by name or by number.  Now if you click Ctrl-S while entering the name or number it will switch the sort order.
  • Contingency Analysis: Modified so that area MW transactions are stored as part of the contingency reference state.
  • File Formats: Modified to allow non-series capacitor branches to be read from a GE EPC file as bypassed.

Bug Fixes

  • User Interface Dialogs: When using the PTDF dialog to "toggle the flow visualization", errors could occur if the initial flow visualization was not set to MW values only.  This has been fixed.
  • Case Information Displays: The value for OPF Transmission Charge associated with a DC Transmission line was always displayed as a zero in the case info display.  This has been fixed.
  • Case Information Displays: Modified so that Super Area can be deleted in Run Mode.
  • Oneline Diagrams: PowerWorld internally limits the number of vertices on a graphical line to 32,767.  When reading in very detailed GIS Shapefiles however it's possible to come across a line with more points than this.  This is now properly handled by splitting the line up into pieces.
  • Oneline Diagrams: When inserting a bus graphically which was connected to a DC transmission line, an access violation would occur.  This has been fixed.

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July 10, 2006

New Features

  • Oneline Diagrams: Added support for drawing dashed lines with thickness greater than 1. Also fixed so that printing of dashed lines works throughout.
  • Oneline Diagrams: Modified the Format Dialog so that field prefixes can be edited for selected objects.
  • Oneline Diagrams: Modified so that when applying the default drawing values to transformers it properly applies two colors.
  • Oneline Diagrams: Added the ability to right-click on a generator, load, line, etc... display object which has an an associated memo and bring up that memo in a dialog.

Bug Fixes

  • Oneline Diagrams: Added code to prevent any background line from having greater than 32767 points. Simulator does not presently handles lines with more points than this.
  • Oneline Diagrams: Modified the interaction of the Measurement System setting and line/transformer display dialog so that it maintains the distance value properly.

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July 18, 2006

New Features

  • Oneline Diagrams: Modified the Contour Type dialog so that only object types that are on the screen appear on the dialog.
  • Oneline Diagrams: Added ability to use an ellipse or a polygon to select objects on the oneline diagram.
  • Oneline Diagrams: Modified the rectangle and ellipse selector so that holding the Ctrl key down will center the selection region around where you click.
  • Oneline Diagrams: Modified the rectangle and ellipse selector so that holding the Shift key down will force the region to be a square or a circle.
  • Auxiliary Files: Added better error messages when pasting data from Excel or when reading in an AUX file so to better explain why a new object can not be create.
  • Auxiliary Files: Modified pasting from Excel and reading in an AUX file so that new objects can not be created if the required fields are blank.

Bug Fixes

  • General: Simulator was running a background process when nothing else was occurring with Simulator which was using up a large amount of CPU resources.  This was not necessary and has been fixed to run less and at a lower CPU priority.
  • Oneline Diagrams: Fixed minor display error of the generator AVR status on a oneline diagrams. It was possible for a generator to show that it was at a VAR limit when it was actually not. This could only happen if there were multiple generators at the bus and you had recently changed the status of one of them.
  • File Formats: Fixed a potential fatal error when reading in the Q Table section of a version 15.1 EPC file.
  • Power Flow Solution: Cleaned up the behavior when choosing to not allow Simulator to dynamically assign slack buses as necessary.
  • Power Flow Solution: Simulator Version 12 added special matrix manipulation which increased matrix calculation speed on newer processors by about 10%. Older processors however ran this code more slowly. A check was added so that the older processors would revert back to the previous matrix routines.
  • Contingency Analysis: Fixed the routine for reading in the PTI *.con file and old PowerWorld *.ctg format. I/O errors were occurring when doing this.
  • Fault Analysis: Modified the sequence data file read routines so that they only sort records after reading in the entire file. Previously it was resorting after every record which resulted in an extremely slow file read.

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July 27, 2006

New Features

  • Oneline Diagrams: Added ability to copy the format attributes of display object and then paste that format information to the selected display objects. This is done using a Copy Format and Paste Format toolbar button and menu option or via the right-click popup menu on a selection.
  • Case Information Displays: Added a new Bus column for showing the power factor of the combined load and shunt at a bus.

Bug Fixes

  • General: Modified so that the background process Simulator was running is no longer run at all.
  • Oneline Diagrams: Fixed bug in selecting some objects using the new ellipse and polygon selector which was causing some objects to always be selected when they were too small to see.
  • Auxiliary Files: Auxiliary files were only supporting up to 256 variable names in a single data section. This limitation was unnecessary and the limit has been removed.
  • File Formats: Modified the writing out of the GE EPC files which are filtered by area so that MW transactions that don't meet the filter are not written.
  • Power Flow Solution: Fixed bug with phase-shifting transformer control which occurred when the phase-shifter was connected to the system slack bus.
  • PV and QV Curve Tools: Add the ability to save the tracking of devices hitting limits to the results in an AUX file.
  • User Interface Dialogs: Modified the split bus and merge bus dialogs so that you can specify a new bus number larger than 5 characters. Simulator allows bus numbers up to 2,147,483,647 generally.
  • User Interface Dialogs: Changed made for better handling moving the terminals of a three-winding transformer to another bus

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July 28, 2006

New Features

  • None

Bug Fixes

  • Auxiliary Files: Added checks to catch invalid SUBDATA sections which are not terminated properly by a </SUBDATA> tag.  Proper error handling is now done.
  • Case Information Displays: Corrected an error that occurred when creating a new record by pasting data from Excel.  This error was introduced in the previous patch on July 27.
  • User Interface Dialogs: When opening the Simulator Options Dialog, the injection group for use in Island-Based AGC was always being reset to the first injection group.  This has been fixed.

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August 7, 2006

New Features

  • Contingency Analysis: Added the old "Combined Definition and Violation Table" back into Contingency analysis. PowerWorld generally recommends using only the Combined Violation Table and Combined Definition Table options.
  • Auxiliary Files: When choosing to write out interfaces using Name_kV values as the secondary key fields, Simulator was still writing out numbers.  This has been fixed.

Bug Fixes

  • Case Information Displays: Fixed access violation caused by reading in a case that has unlinked objects in the Custom Case Information and then trying to save that case again.
  • Optimal Power Flow: Modified the Area, Zone, and Substations objects average/min/max/std of MW Marg. Cost calculation so that they are determined dynamically from the Bus data. Previously they were calculated only after solving the OPF, which made it so that user-entered bus data could not be used for these dynamically calculated values.
  • Optimal Power Flow: Fixed incorrect Total Cost calculate for a generator which would occur when negative prices were included in a bid curve.
  • Oneline Diagrams: Fixed access violation bug with graphically inserting a new transformer on a oneline diagram.
  • Oneline Diagrams: Fixed error when bringing up the contour dialog when there were no buses on the oneline diagram.
  • Oneline Diagrams: Fixed white line which would appear to the right and bottom of the contour image.

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August 24, 2006

New Features

  • Contingency Analysis: Added new option of "RESPOND" to the PostCTGPreventAGCResponse option. This forces the generator to respond durin the post-contingency solution.
  • Contingency Analysis: Added the ability to view element labels when viewing violations in the contingency tool.
  • Contingency Analysis: Added the ability to pan to object on oneline when selecting a limit violation in the contingency tool. It will pan to the violated element now.

Bug Fixes

  • User Interface Dialogs: Fixed the interaction of the TransLineCalc tool with the older line impedance dialog that doesn't include the line spacing.
  • Oneline Diagrams: When auto-inserting transmission lines, an unnecessary slow call was being made slowing down the auto-insert routine. This has been removed.
  • Oneline Diagrams: When saving Oneline solution options to an AUX file, the color BLACK was not be read back in correctly and was being ignored. Only the color of black (Integer = 0) had this problem.
  • Oneline Diagrams: When deleting a Screen Layer, and choosing the option to "Delete all objects in layer" also, Simulator was not deleting the objects and was instead assigning them to the default layer. This has been fixed.
  • Oneline Diagrams: When choosing to apply a Saved "Oneline Form Option" to a oneline, if you were using a display detail filter to show objects in a particular layer, the objects would not come forward if they were presently not visible. This has been fixed.
  • Oneline Diagrams - Fixed bug occurring when objects that were set to a fixed screen locations were displayed along with the Thumb Nail View. This was resulting in erratic movement of the objects.

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August 31, 2006

New Features

  • None.

Bug Fixes

  • File Formats: Fixed syntax error when writing out PTI *.CON contingency files. We were not writing a space between the OPEN BUS phrase and the bus number.
  • Oneline Diagrams: Fixed bug with using the Area, Zone, Substation, and Bus renumbering tools. When reading the swap list from an auxiliary file, it was not working properly.
  • Available Transfer Capability (ATC): On the ATC Dialog, when using a Super Area as the buyer or seller, the Increase Transfer button on the Analysis Tab was not working. This has been fixed.
  • User Interface Dialogs: When choosing to insert a new MW Transaction from the Transactions List the Transaction Dialog is opened. When inserting a new transactions, clicking on the Switch Directions button caused an access violation. This has been fixed.

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September 6, 2006

New Features

  • None.

Bug Fixes

  • General: Modified so the auto-save PWB file option so the auto-saved files are always saved to the directory of the last opened case file.
  • Case Information Display: Fixed an access violation that could occur when contouring columns in a string grid.
  • Case Information Display: When using the 2D or 3D graphing option, an error could occur when closing the graph. This is now fixed.
  • Oneline Diagrams: If a oneline has no buses or substations on it and you inserted a generator, load, or switched shunt object on a oneline, then the default drawing values could not be looked up for the dialog initially. This was OK, but after completing the insertion of the object it saved the values from the dialog back to the default drawing values which it should not do. This has been fixed.
  • Fault Analysis: Errors were fixed in the fault analysis which could cause problems when solving a several faults while the fault dialog was open.
  • User Interface Dialogs: Changed the font color of the drop-down menu on the Dynamic Formatting Dialog.
  • Power Flow Solution: Simulator's AGC routines had a problem if a Super Area contained an Area which had no load AND no scheduled transactions. This could result in some small movements of generation after each solution. This has been fixed.
  • Available Transfer Capability: When using the Solution Method (IL) then Full contingency, the calculation of the linear step which is done after the full contingency solution was using the solution options and control settings for the post-contingency state. The problem with is that the post-ctg generator AGC status' may be quite different than the pre-contingency ones. To fix this, the pre-contingency AGC status are restored prior to calculating another linear step.

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September 19, 2006

New Features

  • None.

Bug Fixes

  • Power Flow Solution: When switching from Run Mode to Edit Mode, Simulator was temporarily setting the system so that it was NOT using the DC approximation. When switching back to Run Mode it would automatically reset back to the DC approximation. This switching was unnecessary, and if the user saved the PWB file while in Edit mode it would be saved with the DC approximation option not matching the present system state.
  • PV and QV Curve Tool: Changed column captions and field descriptions of the "Critical P and Q" values to say "Max P Mism" and "Max Q Mism" to better reflect what they are.
  • User Interface Dialogs: Fixed error with setting the "Neutral Grounded" check box on the Fault Parameters on the generator dialog when in Edit Mode.

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October 11, 2006

New Features

  • File Formats: Added an warning message to the log when reading in a RAW file which has extra text past the end of the file.
  • Oneline Diagrams: Added the ability to modify the oneline hints to change the time delay at which the hint will appear and then disappear, the maximum pixel width of the hint, and the font attributes (size, name, and style) of the hint.
  • Oneline Diagrams: Made the contour visible in the thumbnail view
  • Oneline Diagrams: Cleaned up some issues with making the thumbnail view translucent when having the thumbnail follow the mouse cursor.
  • Available Transfer Capability (ATC): Added easier access to the island-based AGC control options regarding injection groups. These options are used when iterating the ATC between injection groups.

Bug Fixes

  • General: Modified throughout to prevent a switched shunt block with either zero blocks or zero Mvars to ever exist.
  • File Formats: Fixed a bug when reading transformer elements from the NERC Book of Flowgates which resulted in the transformer being monitored in the wrong direction.
  • Case Information Displays: Fixed the pasting of participation points directly into the participation point case information display.
  • User Interface Dialogs: Modified the tap transmission line dialog so that you can specify a new bus number larger than 5 characters. Simulator allows bus numbers up to 2,147,483,647 generally.
  • User Interface Dialogs: Fixed bug on the Default Drawing Values form which resulted in an access violation when editing a value on the case info display and then closing the dialog before finishing the edit.
  • Oneline Diagrams: Fixed bug that was showing the Mvar flow as the MW flow when using the animated arrows mode "MW and Mvar flow".
  • Sensitivity Calculations: When an interface met the following criteria: Branch A was being monitored, Branch B was being outages, and Branch A was presently OPEN, the Interface flow should report a flow of zero. It was not properly showing zero and this bug has been fixed.
  • PV and QV Curve Tool: If an output file name is not specified, then the PV Curve log file will no longer be created. This was added to prevent two instances of Simulator from trying to write to the same log file.
  • Available Transfer Capability (ATC): Modified the storage of the ATC Initial System State so that it recreates the system state each time the state is updated. Previously it only updated the system state which would not work correctly if the user modified the system after using the ATC tool.
  • Available Transfer Capability (ATC): When iterating on a specific transfer limitation, previously Simulator was not clearly indicating when the buyer or seller runs out of injection. This is now clearly indicated by adding a Transfer Limitation related to the Buyer or Seller Reserves. This limitation is added regardless of the user option about reporting reserve limitation. Also the ATC iteration is stopped at this point.
  • Available Transfer Capability (ATC): When iterating on a specific transfer limitation, Simulator no longer considers the user option regarding "Ignore Limiters Below". Previously this could cause problems.
  • Optimal Power Flow (OPF): A bug was fixed on April 17, 2006 in Simulator 11 which handled control variables approaching infinity. PWB files saved before this could have an invalid OPF state saved. This will be fixed when reading in PWB files now.

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October 30, 2006

New Features

  • Case Information Displays: Removed the constant power, current, and impedance MW and MVar columns as default for Load Records. The total MW and MVar columns are now shown only.
  • Oneline Diagrams: Added the ability to rotate through onelines specified in the keyboard shortcuts in a "slideshow". To cancel the slide show just press the ESC key.
  • Available Transfer Capability (ATC): When using a Super Area as a buyer or seller in the ATC, PTDF, TLR, and voltage senstivities the area participation factors defined for the super areas are used to calculate appropriate sensitivities
  • Sensitivity Calculations: When using a Super Area as a buyer or seller in the ATC, PTDF, TLR, and voltage senstivities the area participation factors defined for the super areas are used to calculate appropriate sensitivities

Bug Fixes

  • General: When moving a generator from one bus to another, Simulator was not always properly updating some internal structures resulting an an error. This has been fixed.
  • User Interface Dialogs: Fixed an error when using the Merge Bus routine which could result an invalid power system.
  • User Interface Dialogs: Added better support for storing the initial state in the Time Step Simulation to allow reseting the initial state.
  • Case Information Displays: In the Injection Group, Participation Point grid, the copying and pasting of data was no longer working. This has been fixed.
  • Case Information Displays: In the Injection Group, Participation Point grid, fixed the toggling of the AutoCalc column to work properly.
  • Oneline Diagrams: Fixed an error when auto-inserting interfaces which resulted in the pies charts being unlinked.
  • Oneline Diagrams: Fixed an error which could result in Emphasis highlighting now working correctly.

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November 9, 2006

New Features

  • Case Information Displays: Add the ability to "Send to Open Office" which mimicks the "Send to Excel" feature.
  • Oneline Diagrams: Added the ability to save the oneline slideshow settings with the Simulator Environment auxiliary file.

Bug Fixes

  • File Formats and User Interface Dialogs: When using the Super Area dialog and specifying Area Participation Factor with each area, these particpation factors would be reset to 1.0 for all areas after reading in a PWB file, or after opening the Area Dialog. This has been fixed so that the values do not get reset.
  • Simulator Automation Server (SimAuto): When using the SendToExcel SimAuto function call and passing the keyword "all", Simulator will include a set of default fields. Previously Simulator required the string to be in all lower case with no spaces. This requirement has been removed.
  • Oneline Diagrams: Fixed the list of oneline display objects dialog so that groups are properly displayed.
  • Oneline Diagrams: When grouping background objects, the grouped objects were not being drawn in the appropriate stack level. Groups behaved as though they were in the Middle Level. This has been fixed.
  • Oneline Diagrams: When reading an ESRI Shapefile, objects that were grouped were being assigned to the Default Layer instead of the user-specified one. This has been fixed.
  • Contingency Analysis: Fixed potential divide-by-zero error when using the Linearized Contingency Analysis and monitoring amp limits.
  • Contingency Analysis: When deleting a Model Condition or Filter, the link from a contingency element to the model criteria was not be properly removed resulting in an access violation. This has been fixed.
  • Available Transfer Capability (ATC): Fixed error that could occur when using the Iterated ATC solution methods resulting in incorrect LODF calculations when iterating on particular transfer limiters.
  • Optimal Power Flow (OPF): Previously the data shown on the LP OPF Dialog, Results, Bus Marginal Controls tab where not populated until you looked at that list display. This prevented the data from being obtained via a script or SimAuto call. The data on that display is now calculated when ever the user asks for it regardless of whether it is to visualize it or grab it via a script or SimAuto Call.

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November 10, 2006

Bug Fixes

  • Contingency Analysis: Interfaces that contain contingent elements can now be monitored if using the Full Power Flow method and AC Power Flow.

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November 28, 2006

New Features

  • File Formats: Added ability to save the DC power flow "B Matrix" equation out to the matlab m-file format.
  • File Formats: When writing EPC files, the two-terminal DC transmission lines' DCLine aloss value is now populated with a 0.0 or a 1.0 depending on the metered end of the DC Line.
  • File Formats: When reading EPC files, a two-terminal DC lines uses the DCLine aloss value to set the metered end of the DC line.
  • File Formats: When writing EPC files, any two-terminal DC transmission lines which is blocked is now written with all DC converters labels as status = 0.0
  • File Formats: When reading EPC files, the three-winding transformer tap ratios are calculated from the transformer base values including fixed taps. These calculations are only precise to 4 decimal points due to the EPC file only writing 4 decimals. Simulator will now round the calculated values to 4 decimal points when reading. This is so that tap ratios of 1.00002 and 0.99998 do not show up all over.
  • File Formats: When reading EPC files, the continuous switched shunts now properly set a flag to initialize them to at a max or min limit if appropriate.
  • File Formats: EPC Files do not support having any load, generation, or shunt devices connected to the intermediate buses of a multi-section line. If a case had such devices they would be missing from the resulting EPC file. To fix this, Simulator will write out the branches as individual branches and the fact that a multi-section line exists will be lost in the EPC file format.
  • File Formats: EPC Files do not support having different statuses for the windings of a three-winding transformer. If a case had such devices the resulting EPC file was inconsistent. To fix this, Simulator will write out the branches as individual branches and the fact that a three-winding transformer exists will be lost in the EPC file format.
  • Auxiliary Files: Added better message log descriptions when an object has blank values for required fields.
  • Case Information Displays: Added the Paste option to the Model Expression Case Information Display.
  • Case Information Displays: When changing the status of a multi-section line, simulator forced a refresh of all open dialogs. This has been removed to speed up changing the status of a multi-section line. However, manual refreshes of some displays may now be necessary.
  • Case Information Displays: Added a new column for a Bus which shows whether a bus is either an intermediate bus of a multi-section line or a star bus of a three-winding transformer.

Bug Fixes

  • File Formats: When reading in a RAW file which contained multi-section lines and then saving this file to a PWB file, the multi-section line definitions were not being maintained. This has been fixed.
  • File Formats: When writing EPC files, if generation ownership was specified such that generators were not owned by the same owner as their terminal bus, then an index out of range error would occur. This has been fixed.
  • File Formats: When writing EPC files, the secondary and tertiary winding tap ratios were not being scaled to match the transformer base. This has been fixed.
  • File Formats: When writing EPC files, a floating point error could occur when writing two-terminal DC lines which were marked as blocked. This has been fixed.
  • File Formats: When writing EPC files, the two-winding transformers' magnetizing reactance values were not being written out.
  • File Formats: When writing EPC files, the three-winding transformers' secondary and tertiary MVA limits were written with values divided by 100 (Sbase).
  • File Formats: When reading EPC files, for two-terminal DC transmission lines the setpoint specified end was always being set to the rectifier. This is now properly set to the appropriate end as specified in the EPC file.
  • Case Information Displays: When right-clicking on a case info display and choosing Load, Auxiliary File, Simulator was not properly sending messages to the message log. This has been fixed.
  • Case Information Displays: Modified Model Expressions so that the variable names are no longer required fields. This was preventing model expressions from being read in if the fields were blank.
  • Case Information Displays: On the Three Winding Transformer Case Information display, the display of the Nominal voltage, MW flow and Mvar flow on the windings was incorrect. The primary flows were actually the secondary, secondary were tertiary, and tertiary were blank. This was only an output error but it has been fixed.
  • Sensitivity Calculations: When performing LODF calculations for interfaces that contain multiple contingency elements, if the contingency elements resulted in the creation of new islands, this was not being handled correctly. This is now properly handled.
  • Fault Analysis: Fixed bug where step up transformers implicitly modeled with generators were incorrectly ignored in the zero sequence if the generator machine itself was designated as ungrounded.
  • Fault Analysis: Fixed bug where series capacitor X values for zero sequence matrix were incorrectly replaced with MinLineX of 0.00001.

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December 1, 2006

New Features

  • General: Added an option for performing the case autosave even when in Run Mode.
  • File Formats: Added a new option in the GE EPC Format (*.epc) (with Options) which allows you to specify that the GE Generator Base Load Flag should be interpreted as the "Post-CTG Prevent AGC Response" field in Simulator.
  • Bus View and Sub View: Added the ability to use the up and down arrows when you are on the edit box for the bus or sub number or name.  When doing so it will cycle through the buses or substations in numerical order.

Bug Fixes

  • User Interface Dialogs: Fixed bug on scaling dialog which prevented you from changing the Scale field for a Bus sometimes.
  • Available Transfer Capability: If a extremely small solution convergence tolerance was used, it was possible in very strange circumstances for the iterated ATC Solution methods to get into an infinite loop.  This would occur when the ramping out of the transfer was done and was caused by the ramping tolerance being equal to 10 times the solution tolerance.  This was fixed by setting the ramping tolerance to a value no smaller than 0.1 MW.

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December 21, 2006

New Features

  • Sensitivity Calculations: Modified the calculation of interfaces with contingent elements when the contingent elements result in isolated buses. Contributions from contingent elements now show more reasonable values.

Bug Fixes

  • Oneline Diagrams: Fixed a potential error when reading very old diagrams (Version 6.0a and earlier) which would result in the diagram not reading in correctly.
  • Case Information Displays: Fixed bug that would not allow field to field comparisons with string type fields. For the comparison value, the field name was being compared rather than the value of the field
  • Contingency Analysis: Fixed bug with the reporting of dV/dQ sensitivity violations with the contingency analysis. It was possible that violations were incorrectly being reported as not active because the multiplier was applied to the current contingency value rather than the base case value.
  • Optimal Power Flow: Immediately after modifying an option on the OPF Options dialog, if you then choose to save the options to a file it did not reflect the change on the dialog. This has been fixed.

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January 3, 2007

New Features

  • User Interface Dialogs: Added new features to better show the branches that are part of a multi-section line. There is now a Branches tab on the Multi-Section Line Information Dialog which shows a list of individual branches. Also, when right-clicking on a multi-section line oneline object (such as on the Bus View) there are also menu options to open the Bus View as well as specific dialogs.
  • Case Information Displays: Modified so that for bus records, the substation number, name, and ID are now enterable in Run Mode.

Bug Fixes

  • Case Information Displays: In the switched shunt records, the column headings for the Switched shunt blocks and Number of steps were incorrect. This has been fixed.
  • PV and QV Curve (PVQV) Tool: When choosing to save the QV Curve options to an Auxiliary file, the quantities to track were not being included in the AUX file. This will now be included.
  • Contingency Analysis: When using the contingency Action for changing the series capacitor reactance, the intended action was not being taken properly. This has been fixed.

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January 10, 2007

New Features

  • None.

Bug Fixes

  • Bus View and Sub View: Related to the new feature from December 1, 2006, which allows you to use up/down arrows to toggle through buses in the Bus View, a minor error was introduced which resulted in you advancing to the first bus as soon as you started typing in the bus edit box.  This has been fixed.

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January 19, 2007

New Features

  • None.

Bug Fixes

  • Fault Analysis: Fixed bug in displaying the flow arrow "direction" of the fault current on a transmission line.  The direction is really determined by the "real power" flow direction and was not being shown correctly for lines with negative series reactances.  Fault currents were still correct and this only effected the oneline display.
  • Oneline Displays: Modified the way in which document link oneline objects make calls to Windows to open the associated file.  This should work better.

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January 25, 2007

New Features

  • None.

Bug Fixes

  • File Formats: The extra fields at the end of the generator records in the EPC file (gov_flag, agc_flag, dispatch_flag, baseload_flag) were not being stored in the PWB file. This has been fixed.
  • Contingency Analysis: The check box option to save the contingency analysis definitions/results in the case PWB file was not being properly managed on the contingency form. This has been fixed.
  • Contingency Analysis: Fixed a potential divide-by-zero error which could occur during linearized contingency calculations if using Area Participation factors for the make-up power.
  • Available Transfer Capability: Fixed a potential divide-by-zero error which could occur during linearized contingency calculations if using Area Participation factors for the make-up power.
  • PV and QV Curve: The area interchange status was not always being correctly reset after a PV Curve run. This has been fixed.
  • PV and QV Curve: The display of the Gen MW value at the Source and Sink on the PV Results tab has been fixed.

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January 30, 2007

New Features

  • None.

Bug Fixes

  • Case Information Displays: On the case information plots, added support for windows locale settings.
  • Power Flow Solution: Added better support multi-terminal DC lines as their converters hit current limits. Previously for converters on power mode, the hitting of current limits was not always handled properly resulting in limitations occuring sooner than necessary
  • Power Flow Solution: Added a new message log entries describing what occurs as limits of multi-terminal DC line converters are encounters.
  • Available Transfer Capability: Fixed bug that prevented using the iterated methods on injection groups that contained only load.
  • Available Transfer Capability: When choosing the option, "Take me to the transfer limit for scenario..." the resulting transfer amount was not the correct amount following individual iteration on the first limiting element. This has been fixed. This was only true when using one of the iterated methods.

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February 7, 2007

New Features

  • Auxiliary Files: Modified the TransferLimiter records so that specific types of transfer limits can be created such as TransferLimitBranch and TransferLimiterInterface records.
  • Power Flow Solution: For DC line records and Multi-Terminal DC line records, the metered end of the line could not be changed. This has been modified so that the user may change this setting.

Bug Fixes

  • Case Information Displays: Eliminated several fields for injection groups that started with the phrase "Sum Of". These fields should not have been visible and always return zero. Other fields are available that show the correct values. For instance, there is a colum "Gen MW Total" that returns a valid sum, while "Sum of Gen MW" was an invalid field and always returned zero.
  • User Interface Dialogs: Fixed an error which could occur when maximizing a dialog. The dialog sometimes appeared as too large a size and not quite maximized.
  • PV and QV Curves: In the QV tool, when a contingency solution can not be achieved Simulator will attempt to add the generator at the bus to the pre-contingency solution and then attempt to resolve the contingency. An error would occur however if an unsolvable contingency solution also resulted in the bus in question being completely disconnected from the rest of the system. This has been fixed..

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February 13, 2007

New Features

  • Auxiliary Files: Modified the Bus field for OPF: Marg MW Cost so that entering a string that starts with the letter "N" or "n" will reset the marginal cost values back to "Not Valid".
  • Auxiliary Files:  Added a new optional parameter to the SaveData() script command. After the filter is specified, you may now include inside a set of brackets a list of variable names specifying the sort order. The format of the values inside the brackets is [variablename1:+:0, variablename2:-:1]. The order of the variable names signifies the priority of the sort. The parameter for + signifies ascending order, - signifies descending. The last parameter is a 0 or 1. 1 means absolute value for numbers and case sensitive for strings. The last parameter is optional and is set to 0 by default. The variable name may also have a colon to indicate the field location integer such as in LineMW:1 used to indicate the MW flow at the to end of a branch. The full format of the script is

    SaveData("filename",filetype,objecttype,[fieldlist],[subdatalist],filter,[SortFieldList]);

    Filter and SortFieldList are both optional.
  • Case Information: Modified the Bus field for OPF: Marg MW Cost so that entering a string that starts with the letter "N" or "n" will reset the marginal cost values back to "Not Valid".

Bug Fixes

  • General: Added the Quick AUX drop-down menu next to the Script Mode button back in.
  • General: Accessing a PowerWorld session from a remote desktop after starting it locally (or vice-versa) now works properly.  Previously an access violation could occur.
  • Contingency Analysis: Fixed a strange error that could occur in contingency analysis, if a contingency resulted in the disconnection of a bus that had a continuous switched shunt which was acting as a PV Bus. Subsequent power flow solutions would not correctly back such a switched shunt off a limit.

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February 16, 2007

New Features

  • Sensitivity Tools: Added a new check-box option "Do not monitor lines that are open" to the Multiple Element LODF calculation.

Bug Fixes

  • Available Transfer Capability: Added a minor change to restoring the reference state of generators in the ATC tool. This was needed so that the Automatic Generation Control routines would not introduce a small inconsistency when running the same ATC study using Iterated Solution Methods twice in succession. Previously the two ATC runs would show small differences. This will not occur anymore.
  • Available Transfer Capability: As part of the ATC results, ATC Extra Monitors store a lookup table of the flow on them at the various transfer levels investigated by the ATC tool. This lookup table was not being properly cleared when a new ATC solution was run (except for multiple scenario studies where it was handled properly). This has been fixed so that the lookup tables are properly cleared at the beginning of all solutions.
  • Power Flow Solution: As part of fix from January 30, we inadvertently add the enforcement of current ratings that are zero. This has been fixed so that current ratings of zero are ignored.

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February 23, 2007

New Features

  • File Formats: When reading in RAW files, if a generator has a RMPCT value of zero, it is now converted to a value of 100.
  • Auxiliary Files: Added the ability to store an "advanced sort" description as part of the the AUX file description of the DataGrid objects.
  • Auxiliary Files: Added new optional parameter "ApplyTransfer" to the ATCDetermineATCFor(RL, G, I, ApplyTransfer) script command. If this value is YES, then after determining the transfer limit for the scenario, the system state will be left at this transfer level. (Note: when using the full contingency solution method, the final state returned will still be the pre-contingency state)
  • Auxiliary Files: Added a new optional script command SaveDataWithExtra(). This is similar to the SaveData() command except that the filetype can only be CSV or CSVNOHEADER. Also, after the SortFieldList is specified, this script command allows you to include inside a set of brackets a list [header_list], and then a second list inside a set of brackets [header_value_list].

    SaveDataWithExtra(“filename”,filetype,objecttype,[fieldlist],[subdatalist],filter,[sortfieldList],[header_list],[header_value_list]);

    The header_list is a comma-delimited list of strings representing additional headers to list with the data. These strings must be non-blank.
    The header_value_list is a comma-delimited list of strings representing the values to list with the additional headers. If specified, there must be as many values specified as there are headers. If not specified, all are assumed to be blank.
    The filter, [sortfieldlist], [header_list], and [header_value_list] are optional. However, if omitting the [header_list] and [header_value_list] then it is recommended that you just use the SaveData command.
     
  • Available Transfer Capability: Added new optional parameter "ApplyTransfer" to the ATCDetermineATCFor(RL, G, I, ApplyTransfer) script command. If this value is YES, then after determining the transfer limit for the scenario, the system state will be left at this transfer level. (Note: when using the full contingency solution method, the final state returned will still be the pre-contingency state)

Bug Fixes

  • Case Information: The values displayed for the MW and MVar throughflow for an area, zone, or substation were not properly including the generation. This has been fixed.
  • Auxiliary Files: Fixed bug where the NumBridges field was not being properly read from an auxiliary file.
  • Oneline Display Options: Fixed error in the renumber buses feature.
  • Oneline Display Options: When auto-inserting lines, gens, shunts and loads simultaneously, the circuit breaker and pie chart sizes were being rounded to an integer size. This has been fixed so that floating point number sizes can be used.

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February 27, 2007

New Features

  • Oneline Diagrams: Removed the restriction that substation, area, zone and super area oneline objects must be wider than they are tall.

Bug Fixes

  • General: Fixed a bug that would only occur if you were adding a three-winding transformer as the FIRST branch element in an empty case.
  • Available Transfer Capability: Choosing to Ramp Transfer on the Analysis tab of the ATC Dialog, if you were using injection groups as the seller and buyer, an access violation would occur. This has been fixed.
  • Available Transfer Capability: In Multi-Scenario ATC Analayis, on the Results tab, When clicking the button Write to Excel or Save to Text Files, a confirmation dialog would appear regarding the sorting of Transfer Limiters. This dialog was not necessary anymore and has been removed.

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February 28, 2007

New Features

  • None.

Bug Fixes

  • Oneline Diagrams: Fixed an access violation that occurred when loading a oneline that contained groupings of display objects that were empty.

  • Oneline Diagrams: Fixed an access violation that occurred when loading an auxiliary file through the oneline link object that changed into Run Mode.

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March 8, 2007

New Features

  • User Interface Dialogs: Added the display of custom floats and strings on the Generator Dialog boxes.

Bug Fixes

  • Auxiliary File Script: Fixed an access violation that occurred when a oneline diagrams was open and the script command MergeBuses was uses.  Some of the oneline objects became incorrectly linked resulting in access violations.

  • Case Information Displays: When saving the list of Advanced Filters to the auxiliary file from the Filters case information display, you always saved ALL filters.  This has been fixed so that only selected filters are saved.

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March 15, 2007

New Features

  • Auxiliary Files: Added support for calling specific sub-types of PartPoints via script commands. This includes PartPointGen, PartPointLoad, PartPointShunt, and PartPointInjectionGroup. By referencing the subtype, the variablenames of the related object can also be called. In this way you can refer to the "GenStatus" of a the "PartPointGen" directly allowing you to retrieve as well as modified Gen fields directly via the PartPointGen objecttype.
  • Auxiliary Files: Added support for calling specific sub-types of InterfaceElements via script commands. This includes InterfaceElementBranch, InterfaceElementBranchOpen, InterfaceElementBranchClose, InterfaceElementDCLine, InterfaceElementGen, InterfaceElementLoad, InterfaceElementInjectionGroup, InterfaceElementMSLine, InterfaceElementInterface. Allows same abilities as for PartPoint sub-types.
  • Auxiliary Files: Modified the Export Case Object Fields feature to not export repetitive lists of fields. For instance PartPointGen only says it has the combination of the Gen and PartPoint fields.
  • Contingency Analysis: Modified the Text file Contingency Report Writer so that it also writes out the load islanded by each contingency.

Bug Fixes

  • File Formats: Fixed an error that could occur when reading Version 26 RAW files resulting in the branch records being read incorrectly if blanks were entered for the branch tap and angle.

  • Power Flow Solution: Fixed the calculation of the tie-line flows for multi-terminal DC transmission lines. Previously, the tie-line flow could only be handle across the entire multi-terminal record. This has been changed so that individual converters and DC lines are treated as the tie line.

  • Optimal Power Flow: When using the OPF to minimize system costs, Simulator does not allow generators with Cost Models of "None" to be dispatched. However when using the objective function of minimum control change, the requirement that Cost Models must exist was still being enforced. This has been fixed so that when using minimum control change cost models are not required.

  • Optimal Power Flow: The treatment with Super Areas of the Cost of Energy and Losses Reference was not behaving correctly and did not allow the user to modify the value away from the default value. This has been fixed.

  • Sensitivity Calculations: Due to fix for bug on October 11, 2006, the ability to monitor the flow on Branch A for the closure of Branch A was not working properly. This is an unusually interface, but is now handled properly.

  • Time Step Simulation: When reading in a pre time-step script command for each time point, Simulator read this in BEFORE it made all the other user-defined input changes. In some situations the user may want to read this in AFTER the other user-defined input changes. This has now been made an option.

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March 20, 2007

New Features

  • Auxiliary Files: For the OpenCase and SaveCase script commands, the ability to save and open a case as an AUX file has been added.
  • Auxiliary Files: Added the ability to delete Area, InterfaceElement, PartPoint, and ContingencyElement objecttypes using the Delete(objecttype) script command.
  • Oneline Diagrams: When applying a contour to the oneline diagram, only buses, substations, etc... that were visible would effect the contour. Thus if objects were hidden due to layers or the Oneline Display Detail the contour would not reflect these objects. A new option has been added that makes this optional.

Bug Fixes

  • Oneline Diagrams: For out of service branches set to show MW and Mvar arrows with the option to not scale arrow size set, Mvar flow arrows would still appear. This has been fixed.

  • Oneline Diagrams: Fixed bug ocurring when relinking loads and generators on the Edit Mode dialog. The ID was not properly set, so in the end, the objects were not being relinked.

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March 21, 2007

New Features

  • None.

Bug Fixes

  • Power Flow Solution: When using the right-click option on the MW Transactions table to "Clear transactions and auto-insert tie-line transactions", transactions for tielines that represent multi-terminal DC lines were not being properly added.  This has been fixed.

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March 26, 2007

New Features

  • None.

Bug Fixes

  • Case Information Displays:  The Injection Group fields for Maximum Mvar Increase and Maximum Mvar Decrease were including generation that was OPEN.  This has been changed so that these fields only include generation which is CLOSED and set to AVR = YES.

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April 5, 2007

New Features

  • User Interface Dialogs: Added a new feature to Determine the Patch Distance from a Bus to all other buses in the system. Option is found under the tool menu.
  • Oneline Diagrams: When auto-inserting new substations, the fields defined in the Default Drawing Values are not automatically added.
  • Oneline Diagrams: When automatically adding fields around a transmission line, the fields now obey the font size setting specified with different voltage levels in the Default Drawing Values.
  • Contingency Analysis: Previously, When running the ATC tool and using the iterated ATC methods, the flows on interfaces which had contingent elements were not automatically updated at each power flow solution. This has been changed so that they now are automatically updated.

Bug Fixes

  • Auxiliary Files: Fixed potential error when reading in branch with a non-zero phase shift if you have not also marked the branch as a transformer. Error would result in saving the case to the PWB file incorrectly.

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April 10, 2007

New Features

  • None.

Bug Fixes

  • Available Transfer Capability: Fixed potential but unlikely infinite loop that could occur when tolerances for the power flow solution and ATC tool iterated methods were set in a specific manner.

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April 11, 2007

New Features

  • None.

Bug Fixes

  • Case Information Display: Fixed an error in the calculation of Bus Group Calculated Fields.

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April 20, 2007

New Features

  • None.

Bug Fixes

  • User Interface Dialogs: When opening the switched shunt dialog in Edit Mode, if the shunt was presently OPEN, then after closing the dialog the Nominal B value of the switched shunt was changed to zero. This has been fixed so that we just leave the nominal value at its present value.

  • Power Flow Solution: Added a check during the switched shunt routines to prevent a switched shunt from operating if the voltage gets to low.

  • Available Transfer Capability: When modeling a contingency using a linearized method, Simulator must determine which nodes will be outaged by the contingency and model them as the loss of power injection. During the iterated solution methods, a flag was not being properly reset which could result in an error during the ATC solution. This has been fixed.

  • PV and QV Curve Tool: When performing graphical plots in the PV curve tool, the x-axis values were always being sorted resulting some incorrect plotting near the nose of the PV curve tool. This has been fixed.Power Flow Solution: Added a check during the switched shunt routines to prevent a switched shunt from operating if the voltage gets to low.

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May 4, 2007

New Features

  • Auxiliary Files: Fixed several auxiliary file script commands that reference a filename so that they correctly interpret directory paths that are relative to the current directory
  • Auxiliary Files: Added new Script command CalculateTLRMultipleElement().  First parameter is either BRANCH, INTERFACE, or BOTH.  Second pararmeter is either SELECTED, OVERLOAD, or CTGOVERLOAD.  Third parameter is either BUYER or SELLER.  Fourth parameter is the transaction (see the help for CalculateTLR script command).  First parameter is either AC, DC or DCPS.

    CalculateTLRMultipleElement(TypeElement, WhichElement, direction, [transactor], LinearMethod);
     
  • Power Flow Solution: Under rare circumstances it's possible for a transformer controlling it's FROM bus to have a negative voltage to tap sensitivity. It doesn't make sense for the transformer to attempt to change its tap in this situation, therefore Simulator will not anymore.
  • Sensitivity Tools: Modified the WTLR calculation so that it doesn't always compare contingency overloads to 100 percent.

Bug Fixes

  • Oneline Diagrams: Shapefiles that contain MultiPoint shapes (these represent groups of points) were not being read properly. This has been fixed.

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May 9, 2007

New Features

  • Available Transfer Capability: Modifications made on October 11, 2006 more properly handled situations when the buyer or seller ran out of injection during the iterated ATC methods. When this occurred the ATC process was aborted and an appropriate limiter was reported. It also aborted when processing the "X Number of Limiters to Iterate On". A change has been so that if a reserve limitation is hit while processing an individual limiter, the remaining "Top X" Limiters will still be processed.

Bug Fixes

  • Optimal Power Flow: When specifying a Specific Bus as the Cost of Energy, Losses, and Congestion Reference for an Area or Super Area, the setting was not being properly saved to the PWB file format. This has been fixed.

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May 17, 2007

New Features

  • Auxiliary Files: Modified the storage of interfaces inside Simulator to accommodate a very large number of interfaces. As previously designed if more than about 1000 interfaces were created, many routines became very slow. Interfaces are now stored in sorted order to allow fast lookups.

Bug Fixes

  • File Formats: When opening a oneline diagram from the bottom of the File menu where a list of recently opened cases is shown, after completing the load of the RAW file, a blank oneline diagram was often opened and an extraneous error message appeared. This has been fixed.

  • Contingency Analysis: While running contingency analysis, Simulator keeps track of a "What Actually Occurred" string to describe what each contingency actually did. There was an error in this test description when bypassing or placing inservice series capacitors. The actually contingency action was correct, on the reported text has been fixed.

  • Contingency Analysis: When running the linearized lossless DC contingency analysis method, it was possible in some situations for the direction of the violation to be shown incorrectly. This magnitude of the violation was still correct, only the direction was reported wrong. This has been fixed.

  • Fault Analysis: When running the fault analysis on a system with a large number of mutual impedances, the solution was unnecessarily slow. This has been fixed to speed up the calculation greatly for systems with a large number of mutual impedances.

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May 29, 2007

New Features

  • Auxiliary Files: Modified features throughout Simulator to allow writing data to an auxiliary file using the object labels. This most often affects the SUBDATA sections for objects such as interfaces, injection groups, or contingency records.
  • Case Information Displays: Modified the All Labels column to allow blank entries which signify that the labels should be deleted

Bug Fixes

  • Available Transfer Capability: Changed the method used to bound the stepsize during the iterated ATC methods. Now, if the stepsize is greater than 70% of the maximum allowed stepsize at that step, the stepsize will be reduced to 70% of the maximum allowed stepsize. The previous check would reduce the stepsize to 70% of the maximum allowed stepsize only if the stepsize was greater than the maximum allowed stepsize.

  • Fault Analysis: When writing out, to a PTI sequence file, a negative sequence generator impedance that is specified as zero we now write out the same value as the positive sequence impedance.

  • Fault Analysis: Fixed bugs in fault calculations. Taps were not correctly included in zero sequence. Phase shift was applied to zero sequence and was not supposed to be. Negative sequence generator impedance was incorrectly applied if the user entered zero for the values. Generator sequence currents were incorrectly calculated for the zero sequence if the zero sequence impedance given was zero.

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June 1, 2007

New Features

  • User Interface Dialogs: PowerWorld has seen strange cases with bus shunt values of +10,000 MW next to another bus with a -10,000 MW shunt. These strange shunts can now be automatically merged using a new feature on the Equivalencing Dialog which goes through the case and merges bus shunts that are across zero-impedance branches.

Bug Fixes

  • File Formats: Fixed rare bug that would occur when unlinked model conditions were read from the PWB file. Bug was introduced due to interaction with new feature added May 29 regarding labels.

  • Auxiliary Files: Fixed bug with viewing oneline diagrams or the Bus View after using the "MOVE" script command

  • SimAuto: Fixed bug preventing the multiple direction PTDF grids from being extracted or sent to Excel using SimAuto

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June 8, 2007

New Features

  • File Formats: Added user prompt when saving the Limit Monitoring Settings from the Limit Monitoring Settings dialog to determine whether to use primary or secondary key fields or labels for identifying elements.

Bug Fixes

  • File Formats: Fixed bug when using interfaces that contained leading or trailing blanks. These interfaces could not be properly identified when they were contained in other elements such as Model Conditions.

  • File Formats: When saving the Limit Monitoring Settings to an auxiliary file from the Limit Monitoring Settings dialog, the .AUX extension is now automatically added to the file name if an extension is not included.

  • Contingency Analysis: Additional fix to the linearized lossless DC contingency analysis method that had been fixed in the May 17, 2007, patch. The direction of the violation is now shown correctly for all possible post-contingency flow options.

  • Oneline Diagrams: When switching to the 3D View, the color of Text Objects would always be black no matter what color was selected in the 2D View. The correct color is now used when switching to the 3D View.

  • Oneline Diagrams: Generic Model Fields are now available in the 3D View. Previously, if a Generic Model Field was added in the 2D View, it would not be displayed when switching to the 3D View.

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June 26, 2007

New Features

  • Auxiliary Files: Added new script command DeleteIncludingContents(*).  Use this to delete objects of a particular type and other objects that these contain. Currently, only multi-section lines can be used with this command.  The branches that belong to multi-section lines will also be deleted along with the multi-section lines.  The intention is to make this script command available for Injection Groups and Interfaces as well.  A filter may optionally be specified to only delete objects that meet a filter.

    DeleteIncludingContents(objecttype, filter);
    objecttype: The objecttype being selected.
    filter: There are four options for the filter:
        Delete(objecttype);: No filter specified means to delete all objects of this type.
        Delete(objecttype, "filtername");: "filtername" means delete those that meet the filter.
        Delete(objecttype, AREAZONE);: AREAZONE means delete those that meet the area/zone filters.
        Delete(objecttype, SELECTED);: SELECTED means delete those whose selected field = YES.

Bug Fixes

  • Contingency Analysis: In the fix for May 17, 2007, the "What Actually Occurred" string for bypassing or placing inservice series cap was now flipped. This has been fixed completely now.

  • Auxiliary Files: Fixed error when reading the Interface Monitor Direction from an AUX file.  It was always being read as FROM->TO even if the AUX file specified it as TO->FROM.

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July 5, 2007

New Features

  • File Formats: Added more error checking to prevent the reading of bad transformer tap values
  • Auxiliary Files: Modified the DeleteIncludingContents() for multi-section lines so that the dummy intermediate buses are also deleted.

Bug Fixes

  • Auxiliary Files: Fixed bug with writing out variable names to auxiliary files and choosing to use secondary keys. Previously, the code was not included to write out the variable names using secondary keys.

  • User Interface Dialogs: In the transmission line tap dialog, the old 8 character bus name limitation was still being enforced. This has been removed.

  • Available Transfer Capability: Fixed infinite loop that could be encountered when using the full contingency method and ramping pre-contingency if a reserve limit is found during the process of determining the next step size when the contingency is actually being implemented.

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July 11, 2007

New Features

  • Change to Retriever only.

Bug Fixes

  • None.

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July 27, 2007

New Features

  • Auxiliary Files: Added new script command DeterminePathDistance([start], BranchDistanceMeasure, BranchFilter, BusField). The first parameter is an the starting place which is enclosed in brackets. The starting place may be either an Area, Zone, SuperArea, SUbstation, Injection Group, or Bus. The second parameter is either X, Z, Length, Nodes, or a variable name for a branch. X means use the series reactance, Z means use sqrt(X^2 + R^2), Length means us the Length field, and Nodes means treat each branch as a length of one. Otherwise use any Branch object variable name. The third parameter is either All, Selected, Closed or the name of a branch Advanced Filter. This parameter is used to specify which branch can be traversed at all. Finally, the fourth parameter is the variablename of a Bus field. This field is populated with the minimum distance from the Start Place to that bus. All buses in the start group will have a distance measure of zero. Buses which can not be reached from the start group will have a distance measure of -1.
  • Auxiliary Files: Added new script command DetermineShortestPath([start], [end], BranchDistanceMeasure, BranchFilter, Filename). The first and second parameters represent a starting place and an ending place. The third and fourth parameters are the same as the parameters for the other new script command DeterminePathDistance. Finally, the fifth parameter is a filename (may be enclosed in quotes) to which the results will be written. The first bus listed in the result text file will be in the end grouping and the last bus listed will be the start grouping. The result text file will have a line for each bus passed. Each line will contain three entries delimited by a space: “Number DistanceMeasure Name”.

Bug Fixes

  • Oneline Diagrams: When using the Custom Floating Point field as the value for the animated flow arrows, the Interface objects would not always show the correct flow direction. This has been fixed.

  • Oneline Diagrams: Modified some toolbar buttons to allow the user to set the animated flow arrows to triangles and the animation parameter to the custom floating point field.

  • Power Flow Solution: When performing the DC power flow solution, generator Mvar outputs are set to zero. This was not occurring for generators that were set to AVR=NO. This has been fixed. Note that the bug had no impact on the solution.

  • User Interface Dialogs: On the System Scaling dialog, fixed bug in which the option "Scale only AGCable Generation and Load" was not working for areas when scaling by bus/area/zone.

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August 21, 2007

New Features

  • Auxiliary Files: Added new script command ExitProgram which exits the program.
  • Available Transfer Capability: Added new option to iterate on contingency if the contingency doesn't solve during the ramping. During the iterations, the step size will be reduced by half until the maximum transfer is achieved that still allows the contingency to solve.
  • PV and QV Curve Tool: PV curve results can now be written in a "single-header" file format making it easier to read a large set of data into Excel.
  • PV and QV Curve Tool: For critical scenarios that are critical because an inadequate voltage was found, we now report the bus and voltage of the lowest inadequate voltage.

Bug Fixes

  • Oneline Diagrams: Fixed bug in which the line thickness wasn't being set properly. The default drawing values were being ignored.

  • Oneline Diagrams: Fixed error when reading Interface Display objects from an Display Auxiliary File (AXD). When reading from an AXD file, the interface name was being truncated to 12 characters even though this is not a limitation. This was resulting in unlinked interface display objects.

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September 26, 2007

New Features

  • User Interface Dialogs: When exporting a oneline diagram as a Shapefile, Simulator would export strings to the DBF by filling the extra space in the file with NULL (ASCII = 0) characters to signify that the string was terminated. Some software has troubles handling these null characters. As a result we know fill in the extra bytes with the space characters (ASCII = 32) instead.

Bug Fixes

  • Memory: Fixed access violation that occured when deleting an object that was referenced in a model expression.

  • User Interface Dialogs: Fixed problem where an existing oneline file was not always saved to the directory from which it was opened. By default, the file will be saved to the original directory unless the user specifies a different directory.

  • Auxiliary Files: Fixed bug when loading in transmission lines from a display auxiliary file that replace existing lines and the existing lines have more vertices than the new line.

  • Auxiliary Files: When writing out Auxiliary Files with SUBDATA sections a dialog appears asking if you want to write the subdata sections using primary keys, secondary keys, or labels. Selections on this dialog were incorrectly be interpretted. This has been fixed.

  • Auxiliary Files: When writing an entire case as an Auxiliary File, we moved the Model Expressions ABOVE the Model Conditions and Model Filters because the Model Expressions can be used by the Model Criteria.

  • Auxiliary Files: Fixed bug with loading specific participation point types.

  • Available Transfer Analysis: Fixed a bug with the iterated ATC methods that could produce inconsistent results if using an injection group that contains load points for the buyer.

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October 1, 2007

New Features

  • Available Transfer Capability: Added new field to transfer limiter results that shows the unaltered MVA limit that is defined with a monitored element.

Bug Fixes

  • Power Flow Solution: Added checks throughout to prevent the two terminal DC lines from having their rectifier or inverter tap ratios set to zero. This should not be allowed and is no longer allowed.

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October 2, 2007

New Features

  • None.

Bug Fixes

  • Power Flow Solution: Added checks throughout to prevent the multi-terminal DC line converters from having their tap ratios set to zero. This should not be allowed and is no longer allowed.

  • File Formats: Fixed a bug that was adding in 11/28/2006 patch related to writing out the fixed tap ratio on the secondary and/or tertiary windings of a three-winding transformer if the transformer nominal voltage base was different than the bus nominal voltage.

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November 15, 2007

New Features

  • Case Information Displays: Added ability to copy/paste the fault analysis input parameters. Also gives ability to read/write from an Auxiliary File.
  • SimAuto: Previously, when starting a SimAuto process, an existing Simulator instance would be taken over by the SimAuto process. This has been changed so that existing Simulator instances are left open and a new Simulator process is started by SimAuto.

Bug Fixes

  • Auxiliary File: Fixed a potential bug that could occur when reading in an AUX file that created a two-terminal DC transmission line. The problem was that the transformer tap ratio was being read as zero causing a divide-by-zero error.

  • SCOPF: Fixed a potential bug that occurs when setting the SCOPF Basecase Solution Method to the Optimal Power Flow. If you were also using fast start generators this could cause errors in the SCOPF solution causing it to terminate at an invalid solution.

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November 21, 2007

New Features

  • None.

Bug Fixes

  • File Format: A bug was introduced in Simulator 13 when writing out PWD oneline files out to version 12 or earlier PWD versions. This bug has been fixed in Version 13, and a fix has also been added to Simulator 12.0 to allow it to gracefully read the PWD files even if they were written incorrectly.

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December 5, 2007

New Features

  • Case Information Displays: Added the ability to copy and paste sequence impedance data for branches.

Bug Fixes

  • General: The Lock and Key mechanism in Simulator relies on the Windows Management Instrumentation (WMI) part of the windows operating system. On rare occasions users were experiencing errors in their WMI installation and as a result the software could not be executed. Fixes have been made to allow the lock/key mechanism to work under these situations, though PowerWorld still recommends fixing the windows installation to ensure the WMI will work properly.

  • Security Coinstrained OPF: Added the storage of several SCOPF solution options in the PWB format which previously were not in the PWB file. This included the SCOPF Base Case Solution Method.

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January 12, 2008

New Features

  • None.

Bug Fixes

  • PV and QV Curves: Fixed access violation that would result when writing out the QV tracking results to file and there were no newly crictical scenarios. The error produced in the QV curve didn't make it clear this was the error, but it is now fixed.

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January 28, 2008

New Features

  • None.

Bug Fixes

  • Power Flow Solution: Fixed bug that would occur when equivalencing a bus that had NO generation, NO load, and NO shunt connected, and was also connect to the system by a single branch with had a non-zero phase shift.
  • Available Transfer Capability: Fixed an error that could occur under specific situations when using the ATC Solution method "(IL) then Full CTG Solution". If the Full Contingency solution repeatedly failed the result wasn't being reflected correctly.

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February 6, 2008

New Features

  • None.

Bug Fixes

  • File Formats: The EPC and RAW file formats have no indication for a generator of "AVR = NO". To replicate this behavior, PowerWorld now writes out the Min/Max VAR of such a generator to be equal to the present Mvr output of the generator.
  • File Formats: The RAW format does not support three-winding transformers without a tertiary winding. Fixed error so that three-winding transformers which do not have at tertiary winding are written out as separate two winding records to the RAW format.
  • File Formats: The RAW format does not allow a rectifier to be the voltage-controlling converter of multi-terminal DC line. Fixed so that when writing out the RAW file it forces the RAW file to show an inverter as the voltage-controlling converter.
  • File Formats: Modified the writing of GE EPC files so that the Generator MVar output is written to 2 decimal places instead of 1.

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New Features/Minor Improvements:

Select the desired item to view all New Features and Improvements since the release of Simulator 11.0

File Formats

  • (June 26, 2006) Modified to allow non-series capacitor branches to be read from a GE EPC file as bypassed.
  • (October 11, 2006) Added an warning message to the log when reading in a RAW file which has extra text past the end of the file.
  • (November 28, 2006) Added ability to save the DC power flow "B Matrix" equation out to the matlab m-file format.
  • (November 28, 2006) When writing EPC files, the two-terminal DC transmission lines' DCLine aloss value is now populated with a 0.0 or a 1.0 depending on the metered end of the DC Line.
  • (November 28, 2006) When reading EPC files, a two-terminal DC lines uses the DCLine aloss value to set the metered end of the DC line.
  • (November 28, 2006) When writing EPC files, any two-terminal DC transmission lines which is blocked is now written with all DC converters labels as status = 0.0
  • (November 28, 2006) When reading EPC files, the three-winding transformer tap ratios are calculated from the transformer base values including fixed taps. These calculations are only precise to 4 decimal points due to the EPC file only writing 4 decimals. Simulator will now round the calculated values to 4 decimal points when reading. This is so that tap ratios of 1.00002 and 0.99998 do not show up all over.
  • (November 28, 2006) When reading EPC files, the continuous switched shunts now properly set a flag to initialize them to at a max or min limit if appropriate.
  • (November 28, 2006) EPC Files do not support having any load, generation, or shunt devices connected to the intermediate buses of a multi-section line. If a case had such devices they would be missing from the resulting EPC file. To fix this, Simulator will write out the branches as individual branches and the fact that a multi-section line exists will be lost in the EPC file format.
  • (November 28, 2006) EPC Files do not support having different statuses for the windings of a three-winding transformer. If a case had such devices the resulting EPC file was inconsistent. To fix this, Simulator will write out the branches as individual branches and the fact that a three-winding transformer exists will be lost in the EPC file format.
  • (December 1, 2006) Added an option for performing the case autosave even when in Run Mode.
  • (December 1, 2006) Added a new option in the GE EPC Format (*.epc) (with Options) which allows you to specify that the GE Generator Base Load Flag should be interpreted as the "Post-CTG Prevent AGC Response" field in Simulator.
  • (February 23, 2007) When reading in RAW files, if a generator has a RMPCT value of zero, it is now converted to a value of 100.
  • (June 8, 2007) Added user prompt when saving the Limit Monitoring Settings from the Limit Monitoring Settings dialog to determine whether to use primary or secondary key fields or labels for identifying elements.
  • (July 5, 2007) Added more error checking to prevent the reading of bad transformer tap values

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Auxiliary Files (SCRIPT and DATA Sections)

  • (June 26, 2006) Modified the Simulator-created auxiliary files for contingency settings, limit monitoring settings, etc... so that when they using the SelectAll() script commands they are followed later by UnselectAll() commands, so that in the end all objects are not selected.
  • (July 18, 2006) Added better error messages when pasting data from Excel or when reading in an AUX file so to better explain why a new object can not be create.
  • (July 18, 2006) Modified pasting from Excel and reading in an AUX file so that new objects can not be created if the required fields are blank.
  • (November 28, 2006) Added better message log descriptions when an object has blank values for required fields.
  • (February 7, 2007) Modified the TransferLimiter records so that specific types of transfer limits can be created such as TransferLimitBranch and TransferLimiterInterface records.
  • (February 13, 2007) Modified the Bus field for OPF: Marg MW Cost so that entering a string that starts with the letter "N" or "n" will reset the marginal cost values back to "Not Valid".
  • (February 13, 2007)  Added a new optional parameter to the SaveData() script command. After the filter is specified, you may now include inside a set of brackets a list of variable names specifying the sort order. The format of the values inside the brackets is [variablename1:+:0, variablename2:-:1]. The order of the variable names signifies the priority of the sort. The parameter for + signifies ascending order, - signifies descending. The last parameter is a 0 or 1. 1 means absolute value for numbers and case sensitive for strings. The last parameter is optional and is set to 0 by default. The variable name may also have a colon to indicate the field location integer such as in LineMW:1 used to indicate the MW flow at the to end of a branch. The full format of the script is

    SaveData("filename",filetype,objecttype,[fieldlist],[subdatalist],filter,[SortFieldList]);

    Filter and SortFieldList are both optional.
  • (February 23, 2007) Added the ability to store an "advanced sort" description as part of the the AUX file description of the DataGrid objects.
  • (February 23, 2007) Added new optional parameter "ApplyTransfer" to the ATCDetermineATCFor(RL, G, I, ApplyTransfer) script command. If this value is YES, then after determining the transfer limit for the scenario, the system state will be left at this transfer level. (Note: when using the full contingency solution method, the final state returned will still be the pre-contingency state)
  • (February 23, 2007) Added a new optional script command SaveDataWithExtra(). This is similar to the SaveData() command except that the filetype can only be CSV or CSVNOHEADER. Also, after the SortFieldList is specified, this script command allows you to include inside a set of brackets a list [header_list], and then a second list inside a set of brackets [header_value_list].

    SaveDataWithExtra(“filename”,filetype,objecttype,[fieldlist],[subdatalist],filter,[sortfieldList],[header_list],[header_value_list]);
    The header_list is a comma-delimited list of strings representing additional headers to list with the data. These strings must be non-blank.
    The header_value_list is a comma-delimited list of strings representing the values to list with the additional headers. If specified, there must be as many values specified as there are headers. If not specified, all are assumed to be blank.
    The filter, [sortfieldlist], [header_list], and [header_value_list] are optional. However, if omitting the [header_list] and [header_value_list] then it is recommended that you just use the SaveData command.
  • (March 15, 2007) Added support for calling specific sub-types of PartPoints via script commands. This includes PartPointGen, PartPointLoad, PartPointShunt, and PartPointInjectionGroup. By referencing the subtype, the variablenames of the related object can also be called. In this way you can refer to the "GenStatus" of a the "PartPointGen" directly allowing you to retrieve as well as modified Gen fields directly via the PartPointGen objecttype.
  • (March 15, 2007) Added support for calling specific sub-types of InterfaceElements via script commands. This includes InterfaceElementBranch, InterfaceElementBranchOpen, InterfaceElementBranchClose, InterfaceElementDCLine, InterfaceElementGen, InterfaceElementLoad, InterfaceElementInjectionGroup, InterfaceElementMSLine, InterfaceElementInterface. Allows same abilities as for PartPoint sub-types.
  • (March 15, 2007) Modified the Export Case Object Fields feature to not export repetitive lists of fields. For instance PartPointGen only says it has the combination of the Gen and PartPoint fields.
  • (March 20, 2007) For the OpenCase and SaveCase script commands, the ability to save and open a case as an AUX file has been added.
  • (March 20, 2007) Added the ability to delete Area, InterfaceElement, PartPoint, and ContingencyElement objecttypes using the Delete(objecttype) script command.
  • (May 4, 2007) Fixed several auxiliary file script commands that reference a filename so that they correctly interpret directory paths that are relative to the current directory
  • (May 4, 2007) Added new Script command CalculateTLRMultipleElement().  First parameter is either BRANCH, INTERFACE, or BOTH.  Second pararmeter is either SELECTED, OVERLOAD, or CTGOVERLOAD.  Third parameter is either BUYER or SELLER.  Fourth parameter is the transaction (see the help for CalculateTLR script command).  First parameter is either AC, DC or DCPS.

    CalculateTLRMultipleElement(TypeElement, WhichElement, direction, [transactor], LinearMethod);
     
  • (May 17, 2007) Modified the storage of interfaces inside Simulator to accommodate a very large number of interfaces. As previously designed if more than about 1000 interfaces were created, many routines became very slow. Interfaces are now stored in sorted order to allow fast lookups.
  • (May 29, 2007) Modified features throughout Simulator to allow writing data to an auxiliary file using the object labels. This most often affects the SUBDATA sections for objects such as interfaces, injection groups, or contingency records.
  • (June 26, 2007) Added new script command DeleteIncludingContents(*).  Use this to delete objects of a particular type and other objects that these contain. Currently, only multi-section lines can be used with this command.  The branches that belong to multi-section lines will also be deleted along with the multi-section lines.  The intention is to make this script command available for Injection Groups and Interfaces as well.  A filter may optionally be specified to only delete objects that meet a filter.

    DeleteIncludingContents(objecttype, filter);
    objecttype: The objecttype being selected.
    filter: There are four options for the filter:
        Delete(objecttype);: No filter specified means to delete all objects of this type.
        Delete(objecttype, "filtername");: "filtername" means delete those that meet the filter.
        Delete(objecttype, AREAZONE);: AREAZONE means delete those that meet the area/zone filters.
        Delete(objecttype, SELECTED);: SELECTED means delete those whose selected field = YES.
  • (July 5, 2007) Modified the DeleteIncludingContents() for multi-section lines so that the dummy intermediate buses are also deleted.
  • (July 27, 2007) Added new script command DeterminePathDistance([start], BranchDistanceMeasure, BranchFilter, BusField). The first parameter is an the starting place which is enclosed in brackets. The starting place may be either an Area, Zone, SuperArea, SUbstation, Injection Group, or Bus. The second parameter is either X, Z, Length, Nodes, or a variable name for a branch. X means use the series reactance, Z means use sqrt(X^2 + R^2), Length means us the Length field, and Nodes means treat each branch as a length of one. Otherwise use any Branch object variable name. The third parameter is either All, Selected, Closed or the name of a branch Advanced Filter. This parameter is used to specify which branch can be traversed at all. Finally, the fourth parameter is the variablename of a Bus field. This field is populated with the minimum distance from the Start Place to that bus. All buses in the start group will have a distance measure of zero. Buses which can not be reached from the start group will have a distance measure of -1.
  • (July 27, 2007) Added new script command DetermineShortestPath([start], [end], BranchDistanceMeasure, BranchFilter, Filename). The first and second parameters represent a starting place and an ending place. The third and fourth parameters are the same as the parameters for the other new script command DeterminePathDistance. Finally, the fifth parameter is a filename (may be enclosed in quotes) to which the results will be written. The first bus listed in the result text file will be in the end grouping and the last bus listed will be the start grouping. The result text file will have a line for each bus passed. Each line will contain three entries delimited by a space: “Number DistanceMeasure Name”.
  • (August 21, 2007) Added new script command ExitProgram which exits the program.

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Simulator Automation Server (SimAuto)

  • (November 15, 2007) Previously, when starting a SimAuto process, an existing Simulator instance would be taken over by the SimAuto process. This has been changed so that existing Simulator instances are left open and a new Simulator process is started by SimAuto.

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Case Information Displays 

  • (June 26, 2006) Added fields to the transmission branch Display/Column options to show the MW Marginal Cost at the From and To Bus.
  • (July 27, 2006) Added a new Bus column for showing the power factor of the combined load and shunt at a bus.
  • (October 30, 2006) Removed the constant power, current, and impedance MW and MVar columns as default for Load Records. The total MW and MVar columns are now shown only.
  • (November 9, 2006) Add the ability to "Send to Open Office" which mimicks the "Send to Excel" feature.
  • (November 28, 2006) Added the Paste option to the Model Expression Case Information Display.
  • (November 28, 2006) When changing the status of a multi-section line, simulator forced a refresh of all open dialogs. This has been removed to speed up changing the status of a multi-section line. However, manual refreshes of some displays may now be necessary.
  • (November 28, 2006) Added a new column for a Bus which shows whether a bus is either an intermediate bus of a multi-section line or a star bus of a three-winding transformer.
  • (January 3, 2007) Modified so that for bus records, the substation number, name, and ID are now enterable in Run Mode.
  • (February 13, 2007) Modified the Bus field for OPF: Marg MW Cost so that entering a string that starts with the letter "N" or "n" will reset the marginal cost values back to "Not Valid".
  • (May 29, 2007) Modified the All Labels column to allow blank entries which signify that the labels should be deleted
  • (November 15, 2007) Added ability to copy/paste the fault analysis input parameters. Also gives ability to read/write from an Auxiliary File.
  • (December 5, 2007) Added the ability to copy and paste sequence impedance data for branches.

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User Interface Dialogs

  • (June 26, 2006) Added Max MW, Min MW, and AGC status fields to the columns on the Line Loading Replicator dialog.
  • (June 26, 2006) Added a keyboard shortcut on the choose dialogs which list devices by name or by number. Now if you click Ctrl-S while entering the name or number it will switch the sort order.
  • (January 3, 2007) Added new features to better show the branches that are part of a multi-section line. There is now a Branches tab on the Multi-Section Line Information Dialog which shows a list of individual branches. Also, when right-clicking on a multi-section line oneline object (such as on the Bus View) there are also menu options to open the Bus View as well as specific dialogs.
  • (March 8, 2007) Added the display of custom floats and strings on the Generator Dialog boxes.
  • (April 5, 2007) Added a new feature to Determine the Patch Distance from a Bus to all other buses in the system. Option is found under the tool menu.
  • (June 1, 2007) PowerWorld has seen strange cases with bus shunt values of +10,000 MW next to another bus with a -10,000 MW shunt. These strange shunts can now be automatically merged using a new feature on the Equivalencing Dialog which goes through the case and merges bus shunts that are across zero-impedance branches.
  • (September 26, 2007) When exporting a oneline diagram as a Shapefile, Simulator would export strings to the DBF by filling the extra space in the file with NULL (ASCII = 0) characters to signify that the string was terminated. Some software has troubles handling these null characters. As a result we know fill in the extra bytes with the space characters (ASCII = 32) instead.

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Oneline Diagrams

  • (June 26, 2006) Modified Measure Lines so that when showing Oneline hints, the measure line will always show a hint with the length of the line.
  • (June 26, 2006) Modified so that if a PWD file is marked as read-only, then Simulator will not prompt the user to save the oneline.
  • (July 10, 2006) Added support for drawing dashed lines with thickness greater than 1. Also fixed so that printing of dashed lines works throughout.
  • (July 10, 2006) Modified the Format Dialog so that field prefixes can be edited for selected objects.
  • (July 10, 2006) Modified so that when applying the default drawing values to transformers it properly applies two colors.
  • (July 10, 2006) Added the ability to right-click on a generator, load, line, etc... display object which has an an associated memo and bring up that memo in a dialog.
  • (July 18, 2006) Modified the Contour Type dialog so that only object types that are on the screen appear on the dialog.
  • (July 18, 2006) Added ability to use an ellipse or a polygon to select objects on the oneline diagram.
  • (July 18, 2006) Modified the rectangle and ellipse selector so that holding the Ctrl key down will center the selection region around where you click.
  • (July 18, 2006) Modified the rectangle and ellipse selector so that holding the Shift key down will force the region to be a square or a circle.
  • (July 27, 2006) Added ability to copy the format attributes of display object and then paste that format information to the selected display objects. This is done using a Copy Format and Paste Format toolbar button and menu option or via the right-click popup menu on a selection.
  • (October 11, 2006) Added the ability to modify the oneline hints to change the time delay at which the hint will appear and then disappear, the maximum pixel width of the hint, and the font attributes (size, name, and style) of the hint.
  • (October 11, 2006) Made the contour visible in the thumbnail view
  • (October 11, 2006) Cleaned up some issues with making the thumbnail view translucent when having the thumbnail follow the mouse cursor.
  • (October 30, 2006) Added the ability to rotate through onelines specified in the keyboard shortcuts in a "slideshow". To cancel the slide show just press the ESC key.
  • (November 9, 2006) Added the ability to save the oneline slideshow settings with the Simulator Environment auxiliary file.
  • (February 27, 2007) Removed the restriction that substation, area, zone and super area oneline objects must be wider than they are tall.
  • (March 20, 2007) When applying a contour to the oneline diagram, only buses, substations, etc... that were visible would effect the contour. Thus if objects were hidden due to layers or the Oneline Display Detail the contour would not reflect these objects. A new option has been added that makes this optional.
  • (April 5, 2007) When auto-inserting new substations, the fields defined in the Default Drawing Values are not automatically added.
  • (April 5, 2007) When automatically adding fields around a transmission line, the fields now obey the font size setting specified with different voltage levels in the Default Drawing Values.

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Bus View and Substation View Onelines

  • (December 1, 2006) Added the ability to use the up and down arrows when you are on the edit box for the bus or sub number or name. When doing so it will cycle through the buses or substations in numerical order.

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Power Flow Solution

  • (February 7, 2007) For DC line records and Multi-Terminal DC line records, the metered end of the line could not be changed. This has been modified so that the user may change this setting.
  • (May 4, 2007) Under rare circumstances it's possible for a transformer controlling it's FROM bus to have a negative voltage to tap sensitivity. It doesn't make sense for the transformer to attempt to change its tap in this situation, therefore Simulator will not anymore.

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Sensitivity Calculations

  • (October 30, 2006) When using a Super Area as a buyer or seller in the ATC, PTDF, TLR, and voltage senstivities the area participation factors defined for the super areas are used to calculate appropriate sensitivities
  • (December 21, 2006) Modified the calculation of interfaces with contingent elements when the contingent elements result in isolated buses. Contributions from contingent elements now show more reasonable values.
  • (February 16, 2007) Added a new check-box option "Do not monitor lines that are open" to the Multiple Element LODF calculation.
  • (May 4, 2007) Modified the WTLR calculation so that it doesn't always compare contingency overloads to 100 percent.

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Contingency Analysis Tool

  • (June 26, 2006) Modified so that area MW transactions are stored as part of the contingency reference state.
  • (August 7, 2006) Added the old "Combined Definition and Violation Table" back into Contingency analysis. PowerWorld generally recommends using only the Combined Violation Table and Combined Definition Table options.
  • (August 24, 2006) Added new option of "RESPOND" to the PostCTGPreventAGCResponse option. This forces the generator to respond durin the post-contingency solution.
  • (August 24, 2006) Added the ability to view element labels when viewing violations in the contingency tool.
  • (August 24, 2006) Added the ability to pan to object on oneline when selecting a limit violation in the contingency tool. It will pan to the violated element now.
  • (March 15, 2007) Modified the Text file Contingency Report Writer so that it also writes out the load islanded by each contingency.
  • (April 5, 2007) Previously, When running the ATC tool and using the iterated ATC methods, the flows on interfaces which had contingent elements were not automatically updated at each power flow solution. This has been changed so that they now are automatically updated.

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PV and QV Curve (PVQV) Tool

  • (August 21, 2007) PV curve results can now be written in a "single-header" file format making it easier to read a large set of data into Excel.
  • (August 21, 2007) For critical scenarios that are critical because an inadequate voltage was found, we now report the bus and voltage of the lowest inadequate voltage.

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Available Transfer Capability (ATC) Tool

  • (October 11, 2006) Added easier access to the island-based AGC control options regarding injection groups. These options are used when iterating the ATC between injection groups.
  • (October 30, 2006) When using a Super Area as a buyer or seller in the ATC, PTDF, TLR, and voltage senstivities the area participation factors defined for the super areas are used to calculate appropriate sensitivities
  • (February 23, 2007) Added new optional parameter "ApplyTransfer" to the ATCDetermineATCFor(RL, G, I, ApplyTransfer) script command. If this value is YES, then after determining the transfer limit for the scenario, the system state will be left at this transfer level. (Note: when using the full contingency solution method, the final state returned will still be the pre-contingency state)
  • (May 9, 2007) Modifications made on October 11, 2006 more properly handled situations when the buyer or seller ran out of injection during the iterated ATC methods. When this occurred the ATC process was aborted and an appropriate limiter was reported. It also aborted when processing the "X Number of Limiters to Iterate On". A change has been so that if a reserve limitation is hit while processing an individual limiter, the remaining "Top X" Limiters will still be processed.
  • (August 21, 2007) Added new option to iterate on contingency if the contingency doesn't solve during the ramping. During the iterations, the step size will be reduced by half until the maximum transfer is achieved that still allows the contingency to solve.
  • (October 1, 2007) Added new field to transfer limiter results that shows the unaltered MVA limit that is defined with a monitored element.

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Optimal Power Flow (OPF) and Security Constrained OPF (SCOPF) Tool

Fault Analysis

  • No new features yet.

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Help

Bug Fixes:

General

  • (July 18, 2006) Simulator was running a background process when nothing else was occurring with Simulator which was using up a large amount of CPU resources.  This was not necessary and has been fixed to run less and at a lower CPU priority.
  • (July 27, 2006) Modified so that the background process Simulator was running is no longer run at all.
  • (September 6, 2006) Modified so the auto-save PWB file option so the auto-saved files are always saved to the directory of the last opened case file.
  • (October 11, 2006) Modified throughout to prevent a switched shunt block with either zero blocks or zero Mvars to ever exist.
  • (October 30, 2006) When moving a generator from one bus to another, Simulator was not always properly updating some internal structures resulting an an error. This has been fixed.
  • (February 13, 2007) Added the Quick AUX drop-down menu next to the Script Mode button back in.
  • (February 13, 2007) Accessing a PowerWorld session from a remote desktop after starting it locally (or vice-versa) now works properly.  Previously an access violation could occur.
  • (February 27, 2007) Fixed a bug that would only occur if you were adding a three-winding transformer as the FIRST branch element in an empty case.
  • (March 15, 2007) When reading in a pre time-step script command for each time point, Simulator read this in BEFORE it made all the other user-defined input changes. In some situations the user may want to read this in AFTER the other user-defined input changes. This has now been made an option.
  • (December 5, 2007) The Lock and Key mechanism in Simulator relies on the Windows Management Instrumentation (WMI) part of the windows operating system. On rare occasions users were experiencing errors in their WMI installation and as a result the software could not be executed. Fixes have been made to allow the lock/key mechanism to work under these situations, though PowerWorld still recommends fixing the windows installation to ensure the WMI will work properly.

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File Formats

  • (July 18, 2006) Fixed a potential fatal error when reading in the Q Table section of a version 15.1 EPC file.
  • (July 27, 2006) Modified the writing out of the GE EPC files which are filtered by area so that MW transactions that don't meet the filter are not written.
  • (August 31, 2006) Fixed syntax error when writing out PTI *.CON contingency files. We were not writing a space between the OPEN BUS phrase and the bus number.
  • (October 11, 2006) Fixed a bug when reading transformer elements from the NERC Book of Flowgates which resulted in the transformer being monitored in the wrong direction.
  • (November 9, 2006) When using the Super Area dialog and specifying Area Participation Factor with each area, these particpation factors would be reset to 1.0 for all areas after reading in a PWB file, or after opening the Area Dialog. This has been fixed so that the values do not get reset.
  • (November 28, 2006) When reading in a RAW file which contained multi-section lines and then saving this file to a PWB file, the multi-section line definitions were not being maintained. This has been fixed.
  • (November 28, 2006) When writing EPC files, if generation ownership was specified such that generators were not owned by the same owner as their terminal bus, then an index out of range error would occur. This has been fixed.
  • (November 28, 2006) When writing EPC files, the secondary and tertiary winding tap ratios were not being scaled to match the transformer base. This has been fixed.
  • (November 28, 2006) When writing EPC files, a floating point error could occur when writing two-terminal DC lines which were marked as blocked. This has been fixed.
  • (November 28, 2006) When writing EPC files, the two-winding transformers' magnetizing reactance values were not being written out.
  • (November 28, 2006) When writing EPC files, the three-winding transformers' secondary and tertiary MVA limits were written with values divided by 100 (Sbase).
  • (November 28, 2006) When reading EPC files, for two-terminal DC transmission lines the setpoint specified end was always being set to the rectifier. This is now properly set to the appropriate end as specified in the EPC file.
  • (January 25, 2007) The extra fields at the end of the generator records in the EPC file (gov_flag, agc_flag, dispatch_flag, baseload_flag) were not being stored in the PWB file. This has been fixed.
  • (March 15, 2007) Fixed an error that could occur when reading Version 26 RAW files resulting in the branch records being read incorrectly if blanks were entered for the branch tap and angle.
  • (May 17, 2007) When opening a oneline diagram from the bottom of the File menu where a list of recently opened cases is shown, after completing the load of the RAW file, a blank oneline diagram was often opened and an extraneous error message appeared. This has been fixed.
  • (June 1, 2007) Fixed rare bug that would occur when unlinked model conditions were read from the PWB file. Bug was introduced due to interaction with new feature added May 29 regarding labels.
  • (October 2, 2007) Fixed a bug that was adding in 11/28/2006 patch related to writing out the fixed tap ratio on the secondary and/or tertiary windings of a three-winding transformer if the transformer nominal voltage base was different than the bus nominal voltage.
  • (November 21, 2007) A bug was introduced in Simulator 13 when writing out PWD oneline files out to version 12 or earlier PWD versions. This bug has been fixed in Version 13, and a fix has also been added to Simulator 12.0 to allow it to gracefully read the PWD files even if they were written incorrectly.
  • (February 6, 2008) The EPC and RAW file formats have no indication for a generator of "AVR = NO". To replicate this behavior, PowerWorld now writes out the Min/Max VAR of such a generator to be equal to the present Mvr output of the generator.
  • (February 6, 2008) The RAW format does not support three-winding transformers without a tertiary winding. Fixed error so that three-winding transformers which do not have at tertiary winding are written out as separate two winding records to the RAW format.
  • (February 6, 2008) The RAW format does not allow a rectifier to be the voltage-controlling converter of multi-terminal DC line. Fixed so that when writing out the RAW file it forces the RAW file to show an inverter as the voltage-controlling converter.
  • (February 6, 2008) Modified the writing of GE EPC files so that the Generator MVar output is written to 2 decimal places instead of 1.

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Auxiliary Files (SCRIPT and DATA Sections)

  • (July 27, 2006) Auxiliary files were only supporting up to 256 variable names in a single data section. This limitation was unnecessary and the limit has been removed.
  • (July 28, 2006) Added checks to catch invalid SUBDATA sections which are not terminated properly by a </SUBDATA> tag. Proper error handling is now done.
  • (August 7, 2006) When choosing to write out interfaces using Name_kV values as the secondary key fields, Simulator was still writing out numbers.  This has been fixed.
  • (February 23, 2007) Fixed bug where the NumBridges field was not being properly read from an auxiliary file.
  • (March 8, 2007 Fixed an access violation that occurred when a oneline diagrams was open and the script command MergeBuses was uses. Some of the oneline objects became incorrectly linked resulting in access violations.
  • (April 5, 2007) Fixed potential error when reading in branch with a non-zero phase shift if you have not also marked the branch as a transformer. Error would result in saving the case to the PWB file incorrectly.
  • (June 1, 2007) Fixed bug with viewing oneline diagrams or the Bus View after using the "MOVE" script command
  • (June 26, 2007) Fixed error when reading the Interface Monitor Direction from an AUX file.  It was always being read as FROM->TO even if the AUX file specified it as TO->FROM.
  • (July 5, 2007) Fixed bug with writing out variable names to auxiliary files and choosing to use secondary keys. Previously, the code was not included to write out the variable names using secondary keys.
  • (September 26, 2007) Fixed bug when loading in transmission lines from a display auxiliary file that replace existing lines and the existing lines have more vertices than the new line.
  • (September 26, 2007) When writing out Auxiliary Files with SUBDATA sections a dialog appears asking if you want to write the subdata sections using primary keys, secondary keys, or labels. Selections on this dialog were incorrectly be interpretted. This has been fixed.
  • (September 26, 2007) When writing an entire case as an Auxiliary File, we moved the Model Expressions ABOVE the Model Conditions and Model Filters because the Model Expressions can be used by the Model Criteria.
  • (September 26, 2007) Fixed bug with loading specific participation point types.
  • (November 15, 2007) Fixed a potential bug that could occur when reading in an AUX file that created a two-terminal DC transmission line. The problem was that the transformer tap ratio was being read as zero causing a divide-by-zero error.

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Simulator Automation Server (SimAuto)

  • (November 9, 2006) When using the SendToExcel SimAuto function call and passing the keyword "all", Simulator will include a set of default fields. Previously Simulator required the string to be in all lower case with no spaces. This requirement has been removed.
  • (June 1, 2007) Fixed bug preventing the multiple direction PTDF grids from being extracted or sent to Excel using SimAuto

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Case Information Displays

  • (June 26, 2006) The value for OPF Transmission Charge associated with a DC Transmission line was always displayed as a zero in the case info display. This has been fixed.
  • (June 26, 2006) Modified so that Super Area can be deleted in Run Mode.
  • (July 27, 2006) Auxiliary files were only supporting up to 256 variable names in a single data section. This limitation was unnecessary and the limit has been removed.
  • (July 28, 2006) Corrected an error that occurred when creating a new record by pasting data from Excel. This error was introduced in the previous patch on July 27.
  • (August 7, 2006) Fixed access violation caused by reading in a case that has unlinked objects in the Custom Case Information and then trying to save that case again.
  • (September 6, 2006) Fixed an access violation that could occur when contouring columns in a string grid.
  • (September 6, 2006) When using the 2D or 3D graphing option, an error could occur when closing the graph. This is now fixed.
  • (October 11, 2006) Fixed the pasting of participation points directly into the participation point case information display.
  • (October 30, 2006) In the Injection Group, Participation Point grid, the copying and pasting of data was no longer working. This has been fixed.
  • (October 30, 2006) In the Injection Group, Participation Point grid, fixed the toggling of the AutoCalc column to work properly.
  • (November 28, 2006) When right-clicking on a case info display and choosing Load, Auxiliary File, Simulator was not properly sending messages to the message log. This has been fixed.
  • (November 28, 2006) Modified Model Expressions so that the variable names are no longer required fields. This was preventing model expressions from being read in if the fields were blank.
  • (November 28, 2006) On the Three Winding Transformer Case Information display, the display of the Nominal voltage, MW flow and Mvar flow on the windings was incorrect. The primary flows were actually the secondary, secondary were tertiary, and tertiary were blank. This was only an output error but it has been fixed.
  • (December 21, 2006) Fixed bug that would not allow field to field comparisons with string type fields. For the comparison value, the field name was being compared rather than the value of the field
  • (January 3, 2007) In the switched shunt records, the column headings for the Switched shunt blocks and Number of steps were incorrect. This has been fixed.
  • (January 30, 2007) On the case information plots, added support for windows locale settings.
  • (February 7, 2007) Eliminated several fields for injection groups that started with the phrase "Sum Of". These fields should not have been visible and always return zero. Other fields are available that show the correct values. For instance, there is a colum "Gen MW Total" that returns a valid sum, while "Sum of Gen MW" was an invalid field and always returned zero.
  • (February 23, 2007) The values displayed for the MW and MVar throughflow for an area, zone, or substation were not properly including the generation. This has been fixed.
  • (March 8, 2007 When saving the list of Advanced Filters to the auxiliary file from the Filters case information display, you always saved ALL filters. This has been fixed so that only selected filters are saved.
  • (March 26, 2007) The Injection Group fields for Maximum Mvar Increase and Maximum Mvar Decrease were including generation that was OPEN.  This has been changed so that these fields only include generation which is CLOSED and set to AVR = YES.
  • (April 11, 2007) Fixed an error in the calculation of Bus Group Calculated Fields.

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User Interface Dialogs

  • (June 26, 2006) When using the PTDF dialog to "toggle the flow visualization", errors could occur if the initial flow visualization was not set to MW values only. This has been fixed.
  • (July 27, 2006) Modified the split bus and merge bus dialogs so that you can specify a new bus number larger than 5 characters. Simulator allows bus numbers up to 2,147,483,647 generally.
  • (July 27, 2006) Changed made for better handling moving the terminals of a three-winding transformer to another bus
  • (July 28, 2006) When opening the Simulator Options Dialog, the injection group for use in Island-Based AGC was always being reset to the first injection group.  This has been fixed.
  • (August 24, 2006) Fixed the interaction of the TransLineCalc tool with the older line impedance dialog that doesn't include the line spacing.
  • (August 31, 2006) When choosing to insert a new MW Transaction from the Transactions List the Transaction Dialog is opened. When inserting a new transactions, clicking on the Switch Directions button caused an access violation. This has been fixed.
  • (September 6, 2006) Changed the font color of the drop-down menu on the Dynamic Formatting Dialog.
  • (September 19, 2006) Fixed error with setting the "Neutral Grounded" check box on the Fault Parameters on the generator dialog when in Edit Mode.
  • (October 11, 2006) Modified the tap transmission line dialog so that you can specify a new bus number larger than 5 characters. Simulator allows bus numbers up to 2,147,483,647 generally.
  • (October 11, 2006) Fixed bug on the Default Drawing Values form which resulted in an access violation when editing a value on the case info display and then closing the dialog before finishing the edit.
  • (October 30, 2006) Fixed an error when using the Merge Bus routine which could result an invalid power system.
  • (October 30, 2006) Added better support for storing the initial state in the Time Step Simulation to allow reseting the initial state.
  • (November 9, 2006) When using the Super Area dialog and specifying Area Participation Factor with each area, these particpation factors would be reset to 1.0 for all areas after reading in a PWB file, or after opening the Area Dialog. This has been fixed so that the values do not get reset.
  • (December 1, 2006) Fixed bug on scaling dialog which prevented you from changing the Scale field for a Bus sometimes.
  • (February 7, 2007) Fixed an error which could occur when maximizing a dialog. The dialog sometimes appeared as too large a size and not quite maximized.
  • (April 20, 2007) When opening the switched shunt dialog in Edit Mode, if the shunt was presently OPEN, then after closing the dialog the Nominal B value of the switched shunt was changed to zero. This has been fixed so that we just leave the nominal value at its present value.
  • (July 5, 2007) In the transmission line tap dialog, the old 8 character bus name limitation was still being enforced. This has been removed.
  • (July 27, 2007) On the System Scaling dialog, fixed bug in which the option "Scale only AGCable Generation and Load" was not working for areas when scaling by bus/area/zone.
  • (September 26, 2007) Fixed problem where an existing oneline file was not always saved to the directory from which it was opened. By default, the file will be saved to the original directory unless the user specifies a different directory.

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Oneline Diagrams

  • (June 26, 2006) PowerWorld internally limits the number of vertices on a graphical line to 32,767. When reading in very detailed GIS Shapefiles however it's possible to come across a line with more points than this. This is now properly handled by splitting the line up into pieces.
  • (June 26, 2006) When inserting a bus graphically which was connected to a DC transmission line, an access violation would occur. This has been fixed.
  • (July 10, 2006) Added code to prevent any background line from having greater than 32767 points. Simulator does not presently handles lines with more points than this.
  • (July 10, 2006) Modified the interaction of the Measurement System setting and line/transformer display dialog so that it maintains the distance value properly.
  • (July 18, 2006) Fixed minor display error of the generator AVR status on a oneline diagrams. It was possible for a generator to show that it was at a VAR limit when it was actually not. This could only happen if there were multiple generators at the bus and you had recently changed the status of one of them.
  • (July 27, 2006) Fixed bug in selecting some objects using the new ellipse and polygon selector which was causing some objects to always be selected when they were too small to see.
  • (August 7, 2006) Fixed access violation bug with graphically inserting a new transformer on a oneline diagram.
  • (August 7, 2006) Fixed error when bringing up the contour dialog when there were no buses on the oneline diagram.
  • (August 7, 2006) Fixed white line which would appear to the right and bottom of the contour image.
  • (August 24, 2006) When auto-inserting transmission lines, an unnecessary slow call was being made slowing down the auto-insert routine. This has been removed.
  • (August 24, 2006) When saving Oneline solution options to an AUX file, the color BLACK was not be read back in correctly and was being ignored. Only the color of black (Integer = 0) had this problem.
  • (August 24, 2006) When deleting a Screen Layer, and choosing the option to "Delete all objects in layer" also, Simulator was not deleting the objects and was instead assigning them to the default layer. This has been fixed.
  • (August 24, 2006) When choosing to apply a Saved "Oneline Form Option" to a oneline, if you were using a display detail filter to show objects in a particular layer, the objects would not come forward if they were presently not visible. This has been fixed.
  • (August 24, 2006) Fixed bug occurring when objects that were set to a fixed screen locations were displayed along with the Thumb Nail View. This was resulting in erratic movement of the objects.
  • (August 31, 2006) Fixed bug with using the Area, Zone, Substation, and Bus renumbering tools. When reading the swap list from an auxiliary file, it was not working properly.
  • (September 6, 2006) If a oneline has no buses or substations on it and you inserted a generator, load, or switched shunt object on a oneline, then the default drawing values could not be looked up for the dialog initially. This was OK, but after completing the insertion of the object it saved the values from the dialog back to the default drawing values which it should not do. This has been fixed.
  • (October 11, 2006) Fixed bug that was showing the Mvar flow as the MW flow when using the animated arrows mode "MW and Mvar flow".
  • (October 30, 2006) Fixed an error when auto-inserting interfaces which resulted in the pies charts being unlinked.
  • (October 30, 2006) Fixed an error which could result in Emphasis highlighting now working correctly.
  • (November 9, 2006) Fixed the list of oneline display objects dialog so that groups are properly displayed.
  • (November 9, 2006) When grouping background objects, the grouped objects were not being drawn in the appropriate stack level. Groups behaved as though they were in the Middle Level. This has been fixed.
  • (November 9, 2006) When reading an ESRI Shapefile, objects that were grouped were being assigned to the Default Layer instead of the user-specified one. This has been fixed.
  • (December 21, 2006) Fixed a potential error when reading very old diagrams (Version 6.0a and earlier) which would result in the diagram not reading in correctly.
  • (January 19, 2007) Modified the way in which document link oneline objects make calls to Windows to open the associated file.  This should work better.
  • (February 23, 2007) Fixed error in the renumber buses feature.
  • (February 23, 2007) When auto-inserting lines, gens, shunts and loads simultaneously, the circuit breaker and pie chart sizes were being rounded to an integer size. This has been fixed so that floating point number sizes can be used.

  • (February 28, 2007) Fixed an access violation that occurred when loading a oneline that contained groupings of display objects that were empty.

  • (February 28, 2007) Fixed an access violation that occurred when loading an auxiliary file through the oneline link object that changed into Run Mode.

  • (March 20, 2007) For out of service branches set to show MW and Mvar arrows with the option to not scale arrow size set, Mvar flow arrows would still appear. This has been fixed.

  • (March 20, 2007) Fixed bug ocurring when relinking loads and generators on the Edit Mode dialog. The ID was not properly set, so in the end, the objects were not being relinked.

  • (May 4, 2007) Shapefiles that contain MultiPoint shapes (these represent groups of points) were not being read properly. This has been fixed.

  • (July 27, 2007) When using the Custom Floating Point field as the value for the animated flow arrows, the Interface objects would not always show the correct flow direction. This has been fixed.
  • (July 27, 2007) Modified some toolbar buttons to allow the user to set the animated flow arrows to triangles and the animation parameter to the custom floating point field.
  • (August 21, 2007) Fixed bug in which the line thickness wasn't being set properly. The default drawing values were being ignored.
  • (August 21, 2007) Fixed error when reading Interface Display objects from an Display Auxiliary File (AXD). When reading from an AXD file, the interface name was being truncated to 12 characters even though this is not a limitation. This was resulting in unlinked interface display objects.

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Bus View and Substation View Onelines

  • (January 10, 2007) Related to the new feature from December 1, 2006, which allows you to use up/down arrows to toggle through buses in the Bus View, a minor error was introduced which resulted in you advancing to the first bus as soon as you started typing in the bus edit box.  This has been fixed..

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Power Flow Solution

  • (July 18, 2006) Cleaned up the behavior when choosing to not allow Simulator to dynamically assign slack buses as necessary.
  • (July 18, 2006) Simulator Version 12 added special matrix manipulation which increased matrix calculation speed on newer processors by about 10%. Older processors however ran this code more slowly. A check was added so that the older processors would revert back to the previous matrix routines.
  • (July 27, 2006) Fixed bug with phase-shifting transformer control which occurred when the phase-shifter was connected to the system slack bus.
  • (September 6, 2006) Simulator's AGC routines had a problem if a Super Area contained an Area which had no load AND no scheduled transactions. This could result in some small movements of generation after each solution. This has been fixed.
  • (September 19, 2006) When switching from Run Mode to Edit Mode, Simulator was temporarily setting the system so that it was NOT using the DC approximation. When switching back to Run Mode it would automatically reset back to the DC approximation. This switching was unnecessary, and if the user saved the PWB file while in Edit mode it would be saved with the DC approximation option not matching the present system state.
  • (January 30, 2007) Added better support multi-terminal DC lines as their converters hit current limits. Previously for converters on power mode, the hitting of current limits was not always handled properly resulting in limitations occuring sooner than necessary
  • (January 30, 2007) Added a new message log entries describing what occurs as limits of multi-terminal DC line converters are encounters.
  • (February 16, 2007) As part of fix from January 30, we inadvertently add the enforcement of current ratings that are zero. This has been fixed so that current ratings of zero are ignored.
  • (March 15, 2007) Fixed the calculation of the tie-line flows for multi-terminal DC transmission lines. Previously, the tie-line flow could only be handle across the entire multi-terminal record. This has been changed so that individual converters and DC lines are treated as the tie line.
  • (March 21, 2007) When using the right-click option on the MW Transactions table to "Clear transactions and auto-insert tie-line transactions", transactions for tielines that represent multi-terminal DC lines were not being properly added. This has been fixed.
  • (April 20, 2007) Added a check during the switched shunt routines to prevent a switched shunt from operating if the voltage gets to low.
  • (July 27, 2007) When performing the DC power flow solution, generator Mvar outputs are set to zero. This was not occurring for generators that were set to AVR=NO. This has been fixed. Note that the bug had no impact on the solution.
  • (October 1, 2007) Added checks throughout to prevent the two terminal DC lines from having their rectifier or inverter tap ratios set to zero. This should not be allowed and is no longer allowed.
  • (October 2, 2007) Added checks throughout to prevent the multi-terminal DC line converters from having their tap ratios set to zero. This should not be allowed and is no longer allowed.
  • (January 28, 2008) Fixed bug that would occur when equivalencing a bus that had NO generation, NO load, and NO shunt connected, and was also connect to the system by a single branch with had a non-zero phase shift.

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Sensitivity Calculations

  • (October 11, 2006) When an interface met the following criteria: Branch A was being monitored, Branch B was being outages, and Branch A was presently OPEN, the Interface flow should report a flow of zero. It was not properly showing zero and this bug has been fixed.
  • (November 28, 2006) When performing LODF calculations for interfaces that contain multiple contingency elements, if the contingency elements resulted in the creation of new islands, this was not being handled correctly. This is now properly handled.(October 2, 2007) Added checks throughout to prevent the multi-terminal DC line converters from having their tap ratios set to zero. This should not be allowed and is no longer allowed.
  • (March 15, 2007) Due to fix for bug on October 11, 2006, the ability to monitor the flow on Branch A for the closure of Branch A was not working properly. This is an unusually interface, but is now handled properly.

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Contingency Analysis Tool

  • (July 18, 2006) Fixed the routine for reading in the PTI *.con file and old PowerWorld *.ctg format. I/O errors were occurring when doing this.
  • (November 9, 2006) Fixed potential divide-by-zero error when using the Linearized Contingency Analysis and monitoring amp limits.
  • (November 9, 2006) When deleting a Model Condition or Filter, the link from a contingency element to the model criteria was not be properly removed resulting in an access violation. This has been fixed.
  • (November 10, 2006) Interfaces that contain contingent elements can now be monitored if using the Full Power Flow method and AC Power Flow.
  • (December 21, 2006) Fixed bug with the reporting of dV/dQ sensitivity violations with the contingency analysis. It was possible that violations were incorrectly being reported as not active because the multiplier was applied to the current contingency value rather than the base case value.
  • (January 3, 2007) When using the contingency Action for changing the series capacitor reactance, the intended action was not being taken properly. This has been fixed.
  • (January 25, 2007) The check box option to save the contingency analysis definitions/results in the case PWB file was not being properly managed on the contingency form. This has been fixed.
  • (January 25, 2007) Fixed a potential divide-by-zero error which could occur during linearized contingency calculations if using Area Participation factors for the make-up power.
  • (February 13, 2007) Fixed a strange error that could occur in contingency analysis, if a contingency resulted in the disconnection of a bus that had a continuous switched shunt which was acting as a PV Bus. Subsequent power flow solutions would not correctly back such a switched shunt off a limit.
  • (May 17, 2007) While running contingency analysis, Simulator keeps track of a "What Actually Occurred" string to describe what each contingency actually did. There was an error in this test description when bypassing or placing inservice series capacitors. The actually contingency action was correct, on the reported text has been fixed.
  • (May 17, 2007) When running the linearized lossless DC contingency analysis method, it was possible in some situations for the direction of the violation to be shown incorrectly. This magnitude of the violation was still correct, only the direction was reported wrong. This has been fixed.
  • (June 26, 2007) In the fix for May 17, 2007, the "What Actually Occurred" string for bypassing or placing inservice series cap was now flipped. This has been fixed completely now.

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PV and QV Curve (PVQV) Tool

  • (July 27, 2006) Add the ability to save the tracking of devices hitting limits to the results in an AUX file.
  • (September 19, 2006) Changed column captions and field descriptions of the "Critical P and Q" values to say "Max P Mism" and "Max Q Mism" to better reflect what they are.
  • (October 11, 2006) If an output file name is not specified, then the PV Curve log file will no longer be created. This was added to prevent two instances of Simulator from trying to write to the same log file.
  • (January 3, 2007) When choosing to save the QV Curve options to an Auxiliary file, the quantities to track were not being included in the AUX file. This will now be included.
  • (January 25, 2007) The area interchange status was not always being correctly reset after a PV Curve run. This has been fixed.
  • (January 25, 2007) The display of the Gen MW value at the Source and Sink on the PV Results tab has been fixed.
  • (February 7, 2007) In the QV tool, when a contingency solution can not be achieved Simulator will attempt to add the generator at the bus to the pre-contingency solution and then attempt to resolve the contingency. An error would occur however if an unsolvable contingency solution also resulted in the bus in question being completely disconnected from the rest of the system. This has been fixed.
  • (April 20, 2007) When performing graphical plots in the PV curve tool, the x-axis values were always being sorted resulting some incorrect plotting near the nose of the PV curve tool. This has been fixed.
  • (January 12, 2008) Fixed access violation that would result when writing out the QV tracking results to file and there were no newly crictical scenarios. The error produced in the QV curve didn't make it clear this was the error, but it is now fixed.

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Available Transfer Capability (ATC) Tool

  • (August 31, 2006) On the ATC Dialog, when using a Super Area as the buyer or seller, the Increase Transfer button on the Analysis Tab was not working. This has been fixed.
  • (September 6, 2006) When using the Solution Method (IL) then Full contingency, the calculation of the linear step which is done after the full contingency solution was using the solution options and control settings for the post-contingency state. The problem with is that the post-ctg generator AGC status' may be quite different than the pre-contingency ones. To fix this, the pre-contingency AGC status are restored prior to calculating another linear step.
  • (October 11, 2006) Modified the storage of the ATC Initial System State so that it recreates the system state each time the state is updated. Previously it only updated the system state which would not work correctly if the user modified the system after using the ATC tool.
  • (October 11, 2006) When iterating on a specific transfer limitation, previously Simulator was not clearly indicating when the buyer or seller runs out of injection. This is now clearly indicated by adding a Transfer Limitation related to the Buyer or Seller Reserves. This limitation is added regardless of the user option about reporting reserve limitation. Also the ATC iteration is stopped at this point.
  • (October 11, 2006) When iterating on a specific transfer limitation, Simulator no longer considers the user option regarding "Ignore Limiters Below". Previously this could cause problems.
  • (November 9, 2006) Fixed error that could occur when using the Iterated ATC solution methods resulting in incorrect LODF calculations when iterating on particular transfer limiters.
  • (December 1, 2006) If a extremely small solution convergence tolerance was used, it was possible in very strange circumstances for the iterated ATC Solution methods to get into an infinite loop.  This would occur when the ramping out of the transfer was done and was caused by the ramping tolerance being equal to 10 times the solution tolerance.  This was fixed by setting the ramping tolerance to a value no smaller than 0.1 MW.
  • (January 25, 2007) Fixed a potential divide-by-zero error which could occur during linearized contingency calculations if using Area Participation factors for the make-up power.
  • (January 30, 2007) Fixed bug that prevented using the iterated methods on injection groups that contained only load.
  • (January 30, 2007) When choosing the option, "Take me to the transfer limit for scenario..." the resulting transfer amount was not the correct amount following individual iteration on the first limiting element. This has been fixed. This was only true when using one of the iterated methods.
  • (February 16, 2007) Added a minor change to restoring the reference state of generators in the ATC tool. This was needed so that the Automatic Generation Control routines would not introduce a small inconsistency when running the same ATC study using Iterated Solution Methods twice in succession. Previously the two ATC runs would show small differences. This will not occur anymore.
  • (February 16, 2007) As part of the ATC results, ATC Extra Monitors store a lookup table of the flow on them at the various transfer levels investigated by the ATC tool. This lookup table was not being properly cleared when a new ATC solution was run (except for multiple scenario studies where it was handled properly). This has been fixed so that the lookup tables are properly cleared at the beginning of all solutions.
  • (February 27, 2007) Choosing to Ramp Transfer on the Analysis tab of the ATC Dialog, if you were using injection groups as the seller and buyer, an access violation would occur. This has been fixed.
  • (February 27, 2007) In Multi-Scenario ATC Analayis, on the Results tab, When clicking the button Write to Excel or Save to Text Files, a confirmation dialog would appear regarding the sorting of Transfer Limiters. This dialog was not necessary anymore and has been removed.
  • (April 10, 2007) Fixed potential but unlikely infinite loop that could occur when tolerances for the power flow solution and ATC tool iterated methods were set in a specific manner.
  • (April 20, 2007) When modeling a contingency using a linearized method, Simulator must determine which nodes will be outaged by the contingency and model them as the loss of power injection. During the iterated solution methods, a flag was not being properly reset which could result in an error during the ATC solution. This has been fixed.
  • (May 29, 2007) Changed the method used to bound the stepsize during the iterated ATC methods. Now, if the stepsize is greater than 70% of the maximum allowed stepsize at that step, the stepsize will be reduced to 70% of the maximum allowed stepsize. The previous check would reduce the stepsize to 70% of the maximum allowed stepsize only if the stepsize was greater than the maximum allowed stepsize.
  • (July 5, 2007) Fixed infinite loop that could be encountered when using the full contingency method and ramping pre-contingency if a reserve limit is found during the process of determining the next step size when the contingency is actually being implemented.
  • (September 26, 2007) Fixed a bug with the iterated ATC methods that could produce inconsistent results if using an injection group that contains load points for the buyer.
  • (January 28, 2008) Fixed an error that could occur under specific situations when using the ATC Solution method "(IL) then Full CTG Solution". If the Full Contingency solution repeatedly failed the result wasn't being reflected correctly.

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Optimal Power Flow (OPF) and Security Constrained OPF (SCOPF) Tool

  • (August 7, 2006) Modified the Area, Zone, and Substations objects average/min/max/std of MW Marg. Cost calculation so that they are determined dynamically from the Bus data. Previously they were calculated only after solving the OPF, which made it so that user-entered bus data could not be used for these dynamically calculated values.
  • (August 7, 2006) Fixed incorrect Total Cost calculate for a generator which would occur when negative prices were included in a bid curve.
  • (October 11, 2006) A bug was fixed on April 17, 2006 in Simulator 11 which handled control variables approaching infinity. PWB files saved before this could have an invalid OPF state saved. This will be fixed when reading in PWB files now.
  • (November 9, 2006) Previously the data shown on the LP OPF Dialog, Results, Bus Marginal Controls tab where not populated until you looked at that list display. This prevented the data from being obtained via a script or SimAuto call. The data on that display is now calculated when ever the user asks for it regardless of whether it is to visualize it or grab it via a script or SimAuto Call.
  • (December 21, 2006) Immediately after modifying an option on the OPF Options dialog, if you then choose to save the options to a file it did not reflect the change on the dialog. This has been fixed.
  • (March 15, 2007) When using the OPF to minimize system costs, Simulator does not allow generators with Cost Models of "None" to be dispatched. However when using the objective function of minimum control change, the requirement that Cost Models must exist was still being enforced. This has been fixed so that when using minimum control change cost models are not required.
  • (March 15, 2007) The treatment with Super Areas of the Cost of Energy and Losses Reference was not behaving correctly and did not allow the user to modify the value away from the default value. This has been fixed.
  • (May 9, 2007) When specifying a Specific Bus as the Cost of Energy, Losses, and Congestion Reference for an Area or Super Area, the setting was not being properly saved to the PWB file format. This has been fixed.
  • (November 15, 2007) Fixed a potential bug that occurs when setting the SCOPF Basecase Solution Method to the Optimal Power Flow. If you were also using fast start generators this could cause errors in the SCOPF solution causing it to terminate at an invalid solution.
  • (December 5, 2007) Added the storage of several SCOPF solution options in the PWB format which previously were not in the PWB file. This included the SCOPF Base Case Solution Method.

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Fault Analysis

  • (July 18, 2006) Modified the sequence data file read routines so that they only sort records after reading in the entire file. Previously it was resorting after every record which resulted in an extremely slow file read.
  • (September 6, 2006) Errors were fixed in the fault analysis which could cause problems when solving a several faults while the fault dialog was open.
  • (November 28, 2006) Fixed bug where step up transformers implicitly modeled with generators were incorrectly ignored in the zero sequence if the generator machine itself was designated as ungrounded.
  • (November 28, 2006) Fixed bug where series capacitor X values for zero sequence matrix were incorrectly replaced with MinLineX of 0.00001.
  • (January 19, 2007) Fixed bug in displaying the flow arrow "direction" of the fault current on a transmission line.  The direction is really determined by the "real power" flow direction and was not being shown correctly for lines with negative series reactances.  Fault currents were still correct and this only effected the oneline display.
  • (May 17, 2007) When running the fault analysis on a system with a large number of mutual impedances, the solution was unnecessarily slow. This has been fixed to speed up the calculation greatly for systems with a large number of mutual impedances.
  • (May 29, 2007) When writing out, to a PTI sequence file, a negative sequence generator impedance that is specified as zero we now write out the same value as the positive sequence impedance.
  • (May 29, 2007) Fixed bugs in fault calculations. Taps were not correctly included in zero sequence. Phase shift was applied to zero sequence and was not supposed to be. Negative sequence generator impedance was incorrectly applied if the user entered zero for the values. Generator sequence currents were incorrectly calculated for the zero sequence if the zero sequence impedance given was zero.

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Memory

  • (September 26, 2007) Fixed access violation that occured when deleting an object that was referenced in a model expression.

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