September 11, 2025
Features and Improvements
- Transient Stability: Updates made to VHVDC2 to no longer freeze dynamic states and to use the measured voltage when calculating the Pmeas/Vmeas uses in the reactive capability curve lookup function.
- Auxiliary Files (SCRIPT and DATA Sections): Fixed Simulator option for DCModelType. The option should be GIgnore but it was previously looking for XIgnore which didn't make sense. This only impacted setting this option via an Auxiliary file.
Bug Fixes
September 9, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): Added DCTransmissionLine to the objects available in the move script command, allowing users to move the dc transmission line.
- Transient Stability: In MSS1 and MSS2 switched shunt dynamic models, the thresholds for low and high voltage switching operations were correct in the data record but swapped in the dynamic model implementation. Users might have observed continuous repeated switching of the switched shunt in the events list, or seen a forced oscillation type of behavior in certain bus voltage magnitude or frequency signals. This has been fixed.
Bug Fixes
September 8, 2025
Features and Improvements
- Oneline Diagrams: On the dialog for Auto-Insert Buses on a oneline, added a new check box option to "Only Insert Buses that are a FixedNumBus".
- Optimal Power Flow (OPF): The OPF option "Distribute Change Among Equal Cost Generators" (added on June 25, 2025) is now renamed more aptly as "Balance Marginally Similar Controls". This option is useful in balancing control variables that have similar sensitivity vectors in the OPF or SCOPF tableau, and providing a dispatch where groups of controls (based on similar sensitivity) will participate in a manner that puts them in the same relative point within their linear cost segments. Without enabling this option, the behavior would be the as it was prior to June 25, which would incrementally assign control changes to one control at a time, until the desired impact is achieved by simplex linear program. The initial June 25 update provided a way to balance only Generator MW controls, and only under certain type of constraints. This present update handles all types of controls and all types of constraints that are present in the simplex tableau.
- Available Transfer Capability (ATC) Tool: The Reverse Buyer/Seller button on the ATC Dialog did not function properly if the existing Buyer and Seller were not the same type (for example both areas or both zones). This has been fixed so the types also are reversed.
- Case Information Displays: On the Contour Column dialog that Calculate Values button has been giving an error. It is now fixed.
Bug Fixes
August 26, 2025
Features and Improvements
- File Formats: When reading an hdbexport file containing CTGL records, modified so that if the B__CTGL is included with this record, then the object will only be read in if the B__CTGL <> 0.
- File Formats: Added support for reading/writing PSS/E RAW Version 36 files.
- General: Ability to see groupings of buses in common Phase Shift Groups - meaning that were all within the same grouping of 30 degree phase shifts in the network topology.
- General: Added a new object called a BranchGroupRating. A BranchGroupRating has a Name and a Description, and then all Branch objects can be assigned to belong to a BranchGroupRating. Then the BranchGroupRating has fields LimitMVAA..LimitMVAO which will show a value if all Branch objects in the BranchGroupRating have the same value. Otherwise these limits fields for a BranchGroupRating will show a blank. These Limit fields for a BranchGroupRating can then be edited to change the respective limit on all Branch objects assigned to the BranchGroupRating to the newly specified value.
- Optimal Power Flow (OPF): With the LP Basis Matrix added a field to show the constraint ID using key fields. This will change based on the case information display option that allows the selection of Key Fields when identifying objects in certain fields.
- Transient Stability: Removed the transient stability option to "MVA Base for Input/Display of Generator Values". Values are now always entered on the generator MVA Base and can no longer be edited on the system MVA base.
- Available Transfer Capability (ATC) Tool: Fixed access violation that could result when running ATC analysis using the (IL) then Full CTG Solution and using a Ramping Method for an injection group Seller of Econimic Merit Order or Merit Order Close.
- Case Information Displays: When using the Load CSV File from any case information display, an access violation could result if clicking the Cancel button instead of choosing a file to open. This has been fixed.
- Distributed Computation: When running script commands for contingency, ATC, QV, and transient stability analysis that allow the use of distributed computing an upfront check is now done to determine if any computers have been specified for use with distributed computing. If not an error results and analysis cannot continue until computers are specified. This error will also result if SimAuto has not been registered.
- Oneline Diagrams: Fixed access violation closing Oneline Marker form.
- Simulator Automation Server (SimAuto): When running multiple instances of SimAuto simultaneously, Windows could return an error message causing Simulator to fail. This was caused by a problem accessing the Windows Registry when multiple SimAutos were doing this simultaneously. We have added code to gracefully handle this and not crash Simulator.
Bug Fixes
August 20, 2025
Features and Improvements
- Contingency Analysis Tool: Added "Use Primary CTG as Reference for Remedial and CTG Actions" option with CTG Combo Analysis. This option will set the system state following the solution of the primary contingency as the reference state for RAS and CTG actions when solving the secondary contingencies. Added "Use Primary CTG as Reference for Limit Monitoring" option with CTG Combo Analysis. This option will set the system state following the solution of the primary contingency as the reference state for determining base case loading and change violations when solving secondary contingencies and determining violations.
- Transient Stability: Added the CLOSE transient stability event for a Bus. This event will only close all of the branches connected to a bus.
- Transient Stability: Added ability for writing a GENQEC model to the DYR format
- Transient Stability: Added ability for reading and writing the GENQEJ model from and to the DYD and DYR formats
- Transient Stability: Added ability to read from a DYR file a USRMDL named GENQEJU and convert to the GENQEJ standard library model
- Transient Stability: Added ability for reading and writing the REEC_E model from and to the DYD and DYR formats. Model is named REECE in the DYR format.
- Transient Stability: Added ability for reading and writing the REGCB1 model from and to the DYR format.
- Optimal Power Flow (OPF): When loads do not have a benefit curve, they should be not dispatchable in the OPF. This bug has been corrected.
Bug Fixes
August 15, 2025
Features and Improvements
- Case Information Displays: Added support for pasting in transformer vector groups and showing the winding configurations for three-winding transformers.
- Integrated Topology Processing (ITP): Fixed access error when saving out a consolidated Case in Integrated Topology Processing if certain unique topologies existed around switched shunts.
- Integrated Topology Processing (ITP): When writing out a Consolidated Case in Integrated Topology Processing as a PWB file, it was possible for the PWB file to contain a Interface Element for branch that no longer existed in the consolidated case.This can happen if the Branch is shorted out by a set of other parallel switching devices. In this situation the PWB file would be corrupted because the element doesn't exist. Two fixes were made to handle this:
(1) We not longer write out such a branch to the Consolidate PWB file and a warning message is written to the log when saving the PWB
(2) When reading an existing PWB file that had been written this way we gracefully handle the non-existant branch and do not create the respective interface element.
Bug Fixes
August 14, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): Added script command RegionLoadShapeFile to load regions directly from a shapefile.
- Auxiliary Files (SCRIPT and DATA Sections): Fixed bug merging buses. We were assuming the bus being merged was the from bus of a incident line to be moved. This wasn't always true, and could cause problems like disappearing 3-winding transformers.
- General: In the Connections Menu there is a new dialog called Find Phase Shift Groups. This shows the user all the case phase shift groups, and has an option to remove the groups.
- Transient Stability: This was a bug in the script command TSPlotSeriesAdd that was not applying the filter correctly. This bug was fixed and now the filter is applied correctly.
Bug Fixes
August 6, 2025
Bug Fixes
- Transient Stability: Fixed an Access Violation happening when loading the REPC_D transient model from a dyd file. The access violation was happening after loading the dyd file and then opening a different case or closing PowerWorld. This issue was fixed.
August 5, 2025
Features and Improvements
- Transient Stability: Added BASOEL2 over-excitation limiter
- Transient Stability: Fixed a bug regarding loading a transient stability switched shunt model from a dyd. When the ID in the dyd file was in a different case than the ID in the case it was not loading the transient model. For example the dyd file has the id on lowercase but the case has the ID in uppercase. This bug is now fixed.
Bug Fixes
July 29, 2025
Bug Fixes
- Optimal Power Flow (OPF): Corrections to the new option in OPF to "Distribute Change Among Equal Cost Generators", which was added on June 25, 2025. The method for grouping and redistribution of MW controls has been changed to ensure that all members of a group have the same relative MW setpoint along their respective current cost curve segments.
July 28, 2025
Features and Improvements
- Transient Stability: Added GENQEJ machine model
- User Interface Dialogs: Adjusted the font color of cells in tables that are object dialogs like piecewise linear cost curves for generators.
- Auxiliary Files (SCRIPT and DATA Sections): Fixed parsing of HOWMUCH parameter for Move script command. There was an error in parsing the HOWMUCH paramater when the AbortOnError parameter was used, causing it to use the default value of 100%. This has been fixed.
- Distributed Computation: Fixed an issue with distributed computer verification where computers that are unavailable remain marked as "Unknown".
Bug Fixes
July 21, 2025
Bug Fixes
- Auxiliary Files (SCRIPT and DATA Sections): The CloseWithBreakers script command was not working correctly if trying to connect a Bus object using breakers. This has been fixed.
- Contingency Analysis: When using OPENCBS actions with contingency analysis and no breakers can be found that isolate the element, an OPEN action on the element itself will be applied. This action is created as a dynamic action that should be cleaned up at the end of contingency analysis. This wasn't happening so extra messages might appear in the message log or What Occurred as subsequent contingency runs are done. This won't affect the contingency results. This has been fixed.
- Transient Stability: Added support for the transient model REGCBU1 to be able to read and write out from and to a dyr file. The model translate to REGC_B in PowerWorld.
July 15, 2025
Bug Fixes
- Auxiliary Files (SCRIPT and DATA Sections): Injection group contingency actions to ChangeBy or SetTo were not being implemented correctly using linear calculations with ATC when using the option to Linearize Makeup Power Calculation. This has been fixed.
- Transient Stability: Modified the CHVDC2 model to ensure enough subinterval integration timesteps are used for large Kir or Kii paramters for for very small time delays in the model.
- Transient Stability: When reading a CHVDC2 model from a DYR file, we now populate several fields in the extra DCLine model fields which are needed to properly write back out an EPC/DYD file pair that matches the system behavior.
- Transient Stability: The DYD file CHVDC2 record does not have several input parameters because these are stored in the EPC file DCLine and DC converter records. Because the DYR file stores this information, we must write that data into the appropriate location so we can write out an EPC/DYD file pair. This includes: DC line inductance, capacitance, converter smoothing inductance, DC margin at inverter, converter current rating, Max and Min alpha at the rectifier, and minimum alpha at the inverter.
July 14, 2025
Bug Fixes
- Auxiliary Files (SCRIPT and DATA Sections): When using the EditMultipleOnelineAction script command and choosing to save to a display auxiliary file, the file extension should be changed to AXD instead of leaving it as PWD. This has been fixed.
- General: There was a bug with the Create Composite Load Model tool which expanded a load model into load pieces along with the transformer and feeder. This issue is now fixed and the tool will split the composite load model into individual components without the bug.
- Transient Stability: Added the Generator Relay GENOOS. It is an Out of Step relay that will behave and be defined exactly as the Branch Relay OOSMHO Relay. The only difference is that the monitor flag meaning is as follows: Monitor. 0 = Alarm; 1 = Trip. The impedance is calculated at the terminal bus of the generator.
July 9, 2025
Bug Fixes
- Auxiliary Files (SCRIPT and DATA Sections): Reading devices from an AUX or Paste with multiple owners could fail to read correctly if the existing device and the Aux record for the device had some of the same owners but in different owner slots. Checking for duplicates was done after reading EACH owner from the Aux, which if true would remove the duplicate right away, rather than allow it during the AUX / Paste read so that owners could be sucessfully shifted to a different slot in the owner list. This has been modified so that removing duplicates is not processed while reading the Aux/Paste record, but rather waits until the end of reading the record to then check the list of multiple owners and remove any duplicates after all fields for the record have been read.
- Security Constrained OPF (SCOPF) Tool: Some marginal price values were being reported incorrectly after the completion of a SCOPF solution. This has been fixed.
- Transient Stability: The REPC_D model was causing a bug in transient stability if the system has an REPC_D model in the case that was causing an "Out of Memory" situation. This bug was fixed and now the simulation will run without problems.
July 2, 2025
Features and Improvements
- Transient Stability: Added the ability to read 3 new commands for a transient contingency element when reading an OTGD file. The commands are for Bus Isolation (Open the bus), Branch Set R and X (Resistance and Reactance) and Opening shunts.
Examples:
1) "bus 'BUS 138'" "isol" 0.56667
2) "secdd 'BUS 500' '22222' '1' 1" "setto 0.0003 xpu" 0.50000
3) "svd 'BUS NAME 345' '99'" "open" 0.56667 - Auxiliary Files (SCRIPT and DATA Sections): Using the special string @CASENAME with script commands and plot features will include the full file path along with the name. Previously, this wasn't always true and depended on how a case was opened.
- Sensitivity Calculations: On the PTDF dialog the button to Visualize PTDFs is showing when the dialog is opened with the Multiple Directions option selected. This button should not be visible when calculating multiple directions. This has been fixed.
Bug Fixes
June 30, 2025
Bug Fixes
- Auxiliary Files (SCRIPT and DATA Sections): When loading an AUX file creating breakers/disconnects inside of a FixedNumBus grouping, the aux file was not permitting the branches to be created without unique IDs. This has been fixed as the IDs inside a FixedNumBus need only be unique between the terminal Bus objects as both terminal FixedNumBus groupings are the same.
June 27, 2025
Bug Fixes
- Oneline Diagrams: Fixed access violation that would result when opening the Oneline Viewer.
- Sensitivity Calculations: Interfaces that have contingency elements will now give the same results (MW and sensitivities) regardless of the order in which the contingency elements are defined in the interface.
- Sensitivity Calculations: It was possible for multiple element shift factor calculations to give different results for interfaces containing contingency elements when compared to the calculation for a single interface. This would happen if there was a least one interface included in the multiple element calculation that isolated generation or load. This has been fixed.
June 25, 2025
Features and Improvements
- Available Transfer Capability (ATC) Tool: Added new fields for a TransferLimiter object under the folder named Contingency Single Element. All of these field will be blank if there is no associated contingency or if the contingency has more than on ContingencyElement in it. If the associated contingency has only one contingency element, then it will show the field of that single ContingencyElement.
- Bus View and Substation View Onelines: Modified the Substation View so that it can use the exact same customizations as the Bus View. The substation view customization is much more limited though as it will only use the customizations for Branch Fields. The other fields (Bus, Gen, Load, Shunt) are all still visible on the dialog specifying the customization, but they are not used on the Subview. The customizations of Subview and Busview are share between the two views, so editing them in one location is also editing them in the other.
- Case Information Displays: Added two new fields to a Substation, Area, and Zone to show a space-delimited list of Nominal kVs in the substation. Useful to show on oneline diagrams and the substation view.
- Case Information Displays: Added ability to do column contouring on all matrix case information displays.
- Contingency Analysis Tool: Added new fields for a Contingency object under the folder named Single Element. All of these fields will be blank if the contingency has more than one ContingencyElement in it. If the contingency has only one contingency element, then it will show the field of that single ContingencyElement.
- General: Made improvements to ensure that the message log is not degrading software performance when the message log is not visible.
- Optimal Power Flow (OPF): Added a new option in OPF to "Distribute Change Among Equal Cost Generators". When a group of controls have an identical cost and also identical sensitivities on all binding constraints, then the OPF algorithm will now proportionally move the controls between the breakpoints of the cost curve instead of simply picking the generator with the minimum bus number first.
June 16, 2025
Bug Fixes
- Transient Stability: More modifications for how subinterval integration is handled for CHVDC2
June 12, 2025
Features and Improvements
- Case Information Displays: Modified a Region so that calculated fields of Bus, Gen, Load, Shunt, Branch, etc... will work on a Region
- Case Information Displays: Modified a Region so that it can be used as Device Filter on other object types and also use advanced filters of Regions on other objects.
- Case Information Displays: Modified Region objects so they can belong to ObjectGroups. This way a user can create an ObjectGroup of Regions and use this as a device filter to choose things.
- Oneline Diagrams: Modified oneline object linking to the existing case to accomodate FixedNumBus methods of identifying Gens, Loads, Shunts, Branches, DCLines and MSLine. This was generally supported already for creating new onelines, but when loading an old oneline made on a case that did not include the full topology it was not correctly linking when loading into a case which did contain the full topology.
- Power Flow Solution: The March 12 patch introduced a feature to find problems in RAW file solutions related to FixedNumBus groupings with a mixed status (some buses are connected and others are disconnected). PowerWorld will automatically close in branches to connect generator, load or shunt objects at dead buses that the RAW file solution showed injecting power into the system. This patch ensures that the initial voltage guess for these newly closed in buses is equal to the bus to which these buses are being connnected. Normally Simulator would do this automatically previously, but sometimes when opening the RAW file while in Edit Mode it was not.
- Transient Stability: When exporting transient stability data in the DYD file format, the "_cmpldw" composite load model associated with a PSLF load group (load zone, area, zone, owner) was missing the initial four parameters PMin, PQMin, VMin, kVThresh. This has now been corrected. This change does not impact the exporting of "cmpldw" composite load model associated with an individual PSLF loads that are identified by the bus number and id.
Bug Fixes
June 9, 2025
Features and Improvements
- Case Information Displays: Regions can now be combined on the Regions case info display by right-clicking and selecting Region Records, Combine Selected Regions
- GIC: Implemented the ability to read in the *.gic version 5 files even with full topology cases.
- General: Fixed an access violation that could occur whenever opening a new case or closing Simulator.
- Transient Stability: A recent patch was added to catch non-linear governor gains where either All GV or All PGV values are zero and default them to ignore the non-linear gain block. This was good to catch, but we were also catching as an error when all Gv AND Pgv are zero which has always mean to ignore the gain block. New check will properly ignore when both sets of values are zero and not report an error.
Bug Fixes
June 4, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): Added new script command CalculateTapSense(filtername); The filtername can be empty meaning to do calculation for all transformers. Otherwise it can be a filter string for a Branch object using the same syntax as all other script commands.
- Case Information Displays: adding InjectionGroup fields for MWMaxA, MWMaxB, MWMaxC, MWMaxD, MWMinA, MWMinB, MWMinC, MWMinD and also MWMaxPercentA, etc. The Min/Max fields are enterable fields stored with the case. The Percentage fields show the percentage of the given limit. We expect the MWMax fields to be positive numbers and the MWMin to be negative numbers (for a load limit), but this is not enforced.
- Case Information Displays: Added ability to easily export TPWStringGrid results into shapefiles as long as they have geographic information. It is now available in the right-click menu, Geographic Data Views submenu; the two commands (Save Selected Objects in Shapefile or Save All Objects in ShapeFile) are at the end of the submenu. Data is exported as geographic points, with the exception that Regions are exported as polygons.
- Power Flow Solution: Added additional voltage preprocessing to the AC power flow solution to look for groups of buses connected by low impedance branches and then see if the buses within that group have very different per unit voltages. We can then choose a better initial voltage for this grouping which reduced the initial mismatch if available.
- Transient Stability: Added support to read and write the Bus model REPC_D to PSLF dyd format.
- Transient Stability: Added a new Transient Stability option to set how the relay will only scale/affect the load trips and the dist gen connected to a load. The options are to affect 1) Only Load MW and MVAR, or 2) Dist Gen and Load MW and MVAR. It is a new radio group in the Load Modeling Options. Currently the dist gen in the load were not affected by the load relay or scaling of the loads. That is now changed, and the new option will handle that.
- Transient Stability: fixed error in reading the ESST1C, ESST5C, ESST6C, and ESST7C models from a DYD file. We added the SCLFlag recently to support PowerWorld implementation of allowing a choice where the SCL input occurs. This parameter is not in the DYD file however so we need to handle this.
Bug Fixes
May 28, 2025
Features and Improvements
- General: Added a new button on the Case Information Ribbon for Cleanup Case Memory. This features provides a summary of how much of the PWB storage is being used to store different portions of the case data. In particular Transient Stability results and Geographic Regions can consume a large amount of memory. The dialog then provides convenient mechanisms to delete this information permanently
- Oneline Diagrams: The variable tap ratio is always on the From-Bus side, but on a oneline diagram it was difficult to tell which side that is. Modified the transformer symbol to provide a visual indication about which side of the transformer is the variable tap ratio on.
- Transient Stability: For the IEEEG1_GE and IEEE_G3_GE models, a negative db2 parameter has always been treated as a 0.0 deadband. A warning message has been added to alert the user this is happening.
- Oneline Diagrams: Fixed access violation that could occur when adding a new bus to a Bus Spatial View Oneline.
- Power Flow Solution: Eliminated some unnecessary recalculation of flows and sensitivities for interfaces that contain contingencies. These only need to be redone if there IS a change to system topology or elements in the interface and they were being redone if there MIGHT be a change to the elements within the interface.
- Sensitivity Calculations: The calculation of PTDFs and OTDFs for ATC analysis will now include the impact of losing a bus that is participating in the transfer because contingency actions isolate the bus. Previously only the impact of generator and load outages was included.
- Transient Stability: For non-linear gain look up tables in Governor models (for the gate position signal), additional checks have been added. Previously when all GV AND PGV values were 0.0, then the non-linear gain block was ignored and a fixed gain of 1.0 was used. Additional checking is now done so that if all GV values 0.0 then the non-linear gain block is also ignored. Also, if all PGV values are 0.0 then the non-linear gain block is ignored.
Bug Fixes
May 22, 2025
Bug Fixes
- Power Flow Solution: If you have a solve DC power flow solution, but one of the generator MWs is outside of its MWMin - MWMax limits, the DC power flow solution would not immediately enforce the generator limits. It required a mismatch in MW somewhere in the area to force this to be updated. This is now fixed so that the DC power flow solution will immediately enforce generator MW limits even on a solved DC power solution.
- Transient Stability: For the OEL2C model, the IfdRated input parameter is now used as a base to adjust Kscale automatically. When Kscale is specified as 1.0 and IfdRated <> 0, Kscale is internally calculated as 1/IfdRated. If a model specifies a value of Kscale that is not 1.0, then the Kscale value is retained as-is for the simulation. If a model truely needs a Kscale value of 1.0, then IfdRated must be specified as 0.0 or 1.0.
May 21, 2025
Bug Fixes
- Contingency Analysis: When using linear contingency methods and line outages end up isolating buses, the order of the contingency element definitions could cause slightly different results. This has been fixed.
- General: Fixed access violation error in Anonymize Names in Case.
- Power Flow Solution: Interfaces with open line contingency actions that cause generators, loads, and buses to be isolated will account for these changes in the interface MW flow, shift factors, and PTDFs. Previously only generators and loads that were explicitly modeled as outages in the interface would be handled.
- Security Constrained OPF (SCOPF) Tool: Modified to check the validity of running the SCOPF immediately when attempting to solve an SCOPF. Simulator has long had validity checks to ensuring that areas or superareas existing that were on OPF control and there were generator or load control available for AGC. However, there was not a check immediately to ensure AGC was enabled for the entire case and that Island-based AGC was not enabled. Instead, PowerWorld Simulator would run all the contingencies and then tell there user there was a problem. This has been fixed so the obvious validity checks are done immediately.
- Sensitivity Calculations: Interfaces with open line contingency actions that cause generators, loads, and buses to be isolated will account for these changes in the interface MW flow, shift factors, and PTDFs. Previously only generators and loads that were explicitly modeled as outages in the interface would be handled.
- Time Step Simulation: Bug fix for script command TIMESTEPSaveInputCSV in which the weather values in MPH were not being written.
May 9, 2025
Bug Fixes
- Simulator Automation Server (SimAuto): When using the SaveCase() SimAuto command in a tight loop that may call SaveCase() many times in a short period of time, it was possible for Windows I/O errors to occur. This has been fixed.
- Transient Stability: Fixed an access violation caused by having DC line GIC related objects when starting transient stability.
May 7, 2025
Bug Fixes
- File Formats: For some rare PWB files, an access violation would occur when reading in the transient stability options in the PWB file. Getting this patch will allow you to read the existing PWB file you are having trouble with. The PWB itself was fine, but the reading of it had a bug in rare situations.
- General: It was possible to create an ObjectGroup or Region that had a leading or trailing space in the name which would be unique as compared to not having the spaces. This was confusing and has been fixed.
- User Interface Dialogs: Fixed error on the Set Bus Field From Closest dialog. When choosing a filter for either "Area/Zone filters" or for "Selected" it was not working properly. This has been fixed.
May 5, 2025
Bug Fixes
- Power Flow Solution: Angle smoothing could result in bad voltages estimates if smoothing was attempted across buses that have just been connected. A check has been added to not do smoothing in this situation and only voltage estimates on newly connected buses will be done. This should result in much better voltage estimates.
May 2, 2025
Bug Fixes
- Transient Stability: Fixed a bug in transient stability islanded total value. if the case has an island that was not viable and there was a load with a composite load model, the islanded total value was initialized to a Nan value and was dispalying the incorrect value. This was not affecting the simulation in any way, just was showing the incorrect result. This issue has been fixed.
- User Interface Dialogs: The 'Total Injection Increase/Decrease' and 'Flow Achieved' text boxes on the 'Line Loading Replicator' were not being populated after calculating the injection changes. This has been fixed.
May 1, 2025
Features and Improvements
- Transient Stability: New stability model names REPCGFM_C1 plant controller which has control algorithm for regulating P, Q, V and Frequency
- Power Flow Solution: When interfaces contain line contingencies that cause buses to become islanded, numerical problems can be encountered with the linear solution used for determining the impact of the contingent elements on the other contingent elements within the interface. This can cause inconsistent results. This has been fixed.
Bug Fixes
April 29, 2025
Bug Fixes
- General: When choosing to "Export Object Fields" to either a text file or Excel when a power system case had not yet been opened, an access violation occurred. This has been fixed.
April 28, 2025
Features and Improvements
- Transient Stability: Added support for a new VSCDCLine model in stability named VHVDC2 which is very similar to VHVDC1
- File Formats: Two-Terminal DC line in PowerWorld Simulator have a field for allowing the user to specify the GE EPC file bus number for the DC terminals of the device. If these are populated with 0 values we should should be automatically choosing unused numbers. This automatic calculation was not working properly and is now fixed.
Bug Fixes
April 23, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): DoCTGAction script command will now handle OPENCBS and CLOSECBS actions the same way that contingency analysis implements these actions. Previously these actions were not implemented.
- Available Transfer Capability (ATC) Tool: Changed the name of the bus field ATCMinTransLimMW to instead be ATCMinTransLimMWSource (we will still read the old field ATCMinTransLimMW and map that to ATCMinTransLimMWSource).
- Available Transfer Capability (ATC) Tool: Added a new Bus Field named ATCMinTransLimMWSink which returns the minimum Trans Lim value of the ATC Transfer Limiters where this bus is the Sink of the transfer for a transfer direction studied with Multiple Directions ATC and only a single transfer direction has this bus as the Sink. This field matched the field ATCMinTransLimMWSource for the Source
- Oneline Diagrams: Modified the BusView and SubView so that the right-click options for "Open External Maps" will work by getting the latitude/longitude coordinates from the Bus or Substation. Previously those features were never available because the BusView and SubView were not geographic-based onelines.
- Transient Stability: Modified display of the list of PlayIn signals in the Plot Designer so they are sorted in numerical order of the PlayInInfo always. Previously we were sorting like a string so the order was 0, 1, 10, 11 instead of 0, 1, 2, 3 etc.
- Transient Stability: New stability model names REPCGFM_C1 plant controller for use with machine model REGFM_C1 which has control algorithm for regulating P, Q, V and Frequency
- Transient Stability: Added the Ierr signal under the "OEL Other" folder in the plots section for the OEL2C model.
- User Interface Dialogs: Region information is now shown on the geography page for the bus and substation run-time dialogs; region information is also available in the Case Information displays (geography section) for buses, generators, loads, switched shunts, substations, areas and zones.
- Auxiliary Files (SCRIPT and DATA Sections): There was an access violation caused by removing a user named state via script command via the DeleteState script command if the state did not exist. This has been fixed.
- Case Information Displays: The tool to Export Case Object Fields was only reporting fields that had not been translated. This has been fixed again and all fields will be reported now.
- Case Information Displays: Fixed bug calculating generation in an owner. It was including offline generators in the generation sum. A check on the generation status has been added to fix this.
- Time Step Simulation: fixed a time step simulation issue in which some of the input fields were being shown as blank when the inputs had not yet been processed.
- Transient Stability: The OELInput parameter for the OEL2C model in a PSSE DYR file, has acceptable values of 1 (psse default), 2, 3, which are now correctly translated to the values 1, 0, 3 respectively in PowerWorld Simulator. Earlier, this translation was not being done while reading and writing a DYR. Already saved PWB files will be affected, and users will need to reload a DYR file in order to correctly translate this parameter.
- Transient Stability: The SW1 parameter for the OEL2C model in a PSSE DYR file, has acceptable values of 1, 2, which are now correctly translated to the values 0, 1, respectively in PowerWorld Simulator. Earlier, this translation was not being done while reading and writing a DYR.
- Transient Stability: During initialization of OEL2C, if modification limits is allowed, and if OEL ramp rate logic, Z is greater than or equal to zero, then the Iinst upper limit will be modified to match Iact. This is done to ensure that Ierr is greater than or equal to zero, and VOEL initializes to the upper limit, which is consistent with the OEL being idle.
- Transient Stability: Added initial limit modification for VOELmax1 provided the OEL is being initialized as idle. VOELmax2 and VOELmax3 were already being considered, and had missed to do it for VOELmax1.
Bug Fixes
April 15, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): Do not put any restrictions on AXD script commands for being allowed when a load of an AXD file is treated as a complete oneline. Loading as a complete oneline is assumed when using the LoadAXD script command and creating a new oneline at the same time. At this point there seems to be no reason to restrict when AXD script commands can be applied.
- Available Transfer Capability (ATC) Tool: When using the ATC tool to ramp a scenario to the transfer limit for the scenario, the ramping to this transfer limit might fail if there were any iterated limiters that ended up not being able to solve their contingency and fully find the iterated limiter. This has been fixed.
- Transient Stability: REPC_B model were showing the incorrect sign for fdbd2 and possibly fdbd1 and dbd.
Bug Fixes
April 14, 2025
Features and Improvements
- Transient Stability: Added new Hybrid Inverter-based renewable Machine model named REGFM_C1. This model is called a "hybrid" model because it acts as simultaneously a Grid Forming Converter and a Grid Following Converter. This model is in beta development in conjunction with the WECC Model Validation Subcommittee.
- Contingency Analysis: When writing out CON files with REMOVE SWSHUNT or ADD SWSHUNT commands, modified to ensure that the ID string is also written after the SWSHUNT command. We added ability to read these commands with or without the ID several months ago, but when writing we were still omitting the ID string.
- File Formats: When writing out MVA limits D..K for transformer windings to a RAW file we were mistakenly writing out limits D over and over. This has been fixed.
- Transient Stability: The feature for showing Stability Models with bold fonts to indicate non-default values was no longer working. This has been restored.
- Transient Stability: Fixed error which could cause the final point of a PlayInGen voltage/frequency value to be ignored.
- Transient Stability: There was a bug in REPC_C model where the dialog and columns were only showing the first 11 Switched Shunt objects being controlled by the REPC_C and were missing the 12th if it existed. Now this was fixed.
Bug Fixes
April 9, 2025
Features and Improvements
- Contingency Analysis Tool: Two fields were added for Custom Monitors in Contingency Analysis -- Min Value Ctg Name and Max Value Ctg Name, which show the name of the contingency corresponding to the Min Value Cont. and Max Value Cont. respectively.
- Contingency Analysis Tool: For contingency actions that perform InjectionGroup Set/Change MW values by opening generation or load, a single WhatOccurredDuringContingency entry for the InjectionGroup is created indicating how must generation or load has been tripped and the MW Effect if relevant. This patch adds additional WhatOccurredDuringContingency entries listing the specific generator and loads and how much each has changed the MW injection. This doesn't impact the solution, but adds additional useful reporting.
- Data Checks: Could get a "duplicates not allowed" error when trying to open the Data Check tool. This has been fixed.
- General: Regions: provided option to use a much faster way to save the boundary points in aux files. Improved the region form performance with larger boundary point sets.
- Transient Stability: Added a new transient option called "Allow Creation on Dialog of Faults which Calculate Effect Impedance from Sequence Networks (Not Recommended)". The use of this option is not recommended. When choosing it, you will be able to create fault actions that calculate the effective impedance from the sequence networks. We do not recommend this because most of our users running transient stability do not have sequence network information available and instead make use of features such as applying a given fault impedance or applying a fault to achieve a per unit voltage.
- Auxiliary Files (SCRIPT and DATA Sections): Fixed a bug in the code for reading three winding transformers from an Auxiliary file. We were getting an access violation when a three winding transformer was read that was considered new, but had a duplicate star bus listed as an existing three winding transformer. This requires us to create a new star bus and that was causing an access violation in Simulator. This is now fixed.
- Available Transfer Capability (ATC) Tool: When using one of the iterated ATC methods and the source and sink are injection groups, participation factors will remain constant throughout the analysis even if participation factors are set to be auto calculated. The assumption is they should only be auto-calculated once at the start of running the ATC.
- Data Checks: Could get a "duplicates not allowed" error when trying to open the Data Check tool. This has been fixed.
Bug Fixes
March 31, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): Added a new script command DirectionsAutoInsertReference(SourceType, SinkObject, DeleteExisting, SourceFilterName, OppositeDirection);
SourceType : Bus, Area, Zone, or InjectionGroup
SinkObject: "Slack", or the objectname plus keyfield or label identifiers for a specific Bus, Area, Zone, or InjectionGroup
DeleteExisting: YES or NO
SourceFilterName: a string showing the name of a filter for which Source objects to use
OppositeDirection: YES or NO - Available Transfer Capability (ATC) Tool: Modified the Auto Insertion of Directions dialog to allow the user to specify if the Reference is the Sink or the Source. Previously the Reference was always the Sink. For doing studies of transferring power to large loads it is useful to do the opposite.
- Auxiliary Files (SCRIPT and DATA Sections): The tool to Export Case Object Fields was not properly working. This has been fixed and all fields will be reported now.
- Simulator Automation Server (SimAuto): Updated SimAuto's GetSystemMetrics to correctly report logical processor counts on machines with >64 cores
Bug Fixes
March 25, 2025
Bug Fixes
- Auxiliary Files (SCRIPT and DATA Sections): When loading Model Expressions from auxiliary files the expressions were not properly initialized. This resulted in this error reported with each expression: "ERROR: Expression object not created." This has been fixed.
March 24, 2025
Features and Improvements
- Oneline Diagrams: Added an option to allow the user to specify the amount of spacing between parallel lines on the auto line insertion.
- User Interface Dialogs: Added a few new fields to the Regions dialog; also added field to show the regions associated with a bus.
- Auxiliary Files (SCRIPT and DATA Sections): Fixed bug with loading 3WXformer objects from an Auxiliary file. Objects would not be found correctly.
- Available Transfer Capability (ATC) Tool: When using an iterated method with ATC analysis and the full transfer step is not able to be achieved in the part of the process where all limiters are iterated on to determine the order in which individual limiters will be iterated on, the remaining limiters that are not iterated on individually might have their Trans Lim values increased incorrectly by the amount of transfer that was able to be achieved in the last step of the initial process when the POWERFLOW DIVERGENCE limiter is recorded. This has been fixed.
Bug Fixes
March 21, 2025
Features and Improvements
- Case Information Displays: Added a new field CountTransformer (Number Of\Transformers ) for both a Bus, Zone, Area, and Substation object to show the number of Transformers attached to the Bus, or at buses inside the groupings.
- Case Information Displays: Added new fields for a Bus object named ZBRGenList, ZBRRegBusList, ZBRRegBusConflict, ZBRVoltSetList, and ZBRVoltSetConflict. These fields are then shown on a new case information display available in the Model Explorer under Solutions Details\Regulating Buses Multiple Local. The fields are populated with information when grouping of buses connected by low impedance branches have multiple generators connected to them. They will then show a list of bus number of regulated buses and a list of voltage setpoint voltages, and if there are multiples of these representing a conflict field will say YES. This can be helpful in debugging conflicting input data that is not as obvious as generators at the same bus having different regulation buses or setpoints.
- File Formats: Simulator Version 24 reads the RAW file field for a Branch and Transformer called NAME as an object label. For many years, PowerWorld has also seen RAW files in particular written out of EMS systems that included special syntax inside of Comment strings at the end of RAW file records. These comments included an object label inside of square brackets. This ad-hoc syntax had been used for years by customers to include labels. The original release of Simulator 24 read both of these locations as a label, but the NAME field was given priority and set as the Primary Label inside Simulator. Users however are finding that the values in the comment are more predictably set as labels, so we have changed it so the ad-hoc syntax in the comment string is set as the primary label instead.
- Oneline Diagrams: When reading a Shapefile (*.shp) into a oneline, Simulator will now look inside the PRJ file (if available) at the PROJECTION specified. If the PRJ file has a PROJECTION equal to "Mercator_Auxiliary_Sphere" then Simulator will automatically assume it map projection that is very commonly used for Shapefiles associated with website platforms such as Google Maps, Bing Maps, and so on. When this is detected now, Simulator will automatically convert the coordinates in the SHP files to Latitude/Longitude coordinates using this assumed map projection. In older versions of Simulator the user could click a button on the Modify Tab of the Shapefile import form, but this will now be done immediately upon loading the file.
- Oneline Diagrams: Fixed bug when loading a Shapefile (*shp) if a companion Projection file (*.prj) did not exist. The PRJ file should not be required when reading the SHP file, but an error would appear saying that the file could not be found.
Bug Fixes
March 18, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): The DetermineShortestPath script command was not correctly reading the parameter for BranchDistanceMeasure resulting in a returned error. This has been fixed.
- Contingency Analysis Tool: Fixed linear methods for calculating contingency actions for setting or changing an injection group in merit order. Actions using merit order open were correctly implemented.
- Contingency Analysis Tool: When using linear methods for calculating contingencies, the accounting of the gen or load dropped by injection group Set To and Change By actions used when reporting results was not correct. This has been fixed.
- File Formats: The features added over the last couple patch related to the problem in many RAW files where disconnected generators, loads, and shunt were still providing MW and Mvar to the system has been confirmed as a known problem in the RAW file solutions. This patch modified the dialog appearing telling the user about this problem so the dialog is informational only. PowerWorld will now always close in switching devices to replicate the MW/Mvar flows of the incorrect RAW file solution.
- GIC: Mostly minor changes, including 1) updating the GMD code to show support for TLP-007-4, 2) starting to add support for the new geomagnetic north pole locations, 3) support for viewing GIC files in the file browser, 4) adding an automatic upload of the region buses when they are loaded from an aux file.
- User Interface Dialogs: Added support for user interaction with the Message Log using the Mouse Wheel and keyboard UpArrow, DownArrow, PageUp and PageDown keys.
MouseWheel up and down will scroll the messages log without changing selection.
Ctrl+MouseWheel will zoom in and out (change font size).
Shift+MouseWheel will expand the selection up or down by one row.
Up/Down Arrow will move the selection up/down one row.
Shift+Up/DownArrow will expand the selection up/down one row.
Ctrl+Up/Down will zoom in and out (change font size).
PageUp/PageDown will move the selection up/down the number of visible rows.
Shift+PageUp/PageDown will expand the selection up/down the number of visible rows.
Ctrl+PageUp/PageDown will zoom in and out faster (change font size).
March 14, 2025
Features and Improvements
- Case Information Displays: When right-clicking on a case information display and choosing "Set all Values To", the dialog box that appears will now automatically have the edit box for entering a value focused so you can immediately start typing the number.
- Case Information Displays: Fixed various location where copy/pasting the Latitude and Longitude field into a table was not working.
- Case Information Displays: Generator, Load, and SwitchedShunt objects were not working when copy/pasting (or loading from a CSV) because it would say the key fields were missing, even though the ID field was there. This was NOT impacting auxiliary files, but was unique bug to copy/pasting (or loading from a CSV) which were based on column headings.
- File Formats: The March 12, 2025 patch of Simulator 24 had a bug that would impact the ability of the March 5, 7, and 10 patches ability to read the PWB file produced. The PWB file would still read find in the March 12 patch of Simulator 24, but not the previous patches of Version 24. This patch fixes it so PWB files created are read correctly by all Version 24 patches.
- Transient Stability: Eliminated a validation warning message for svsmo1,2 and3 about "The transient Xc parameter is different from the power flow Xc value". This message was created by mistake, even when the parameters were the same. If they are different values, that is handled in the initialization of the model and do not need a validation warning. The validation warning was removed from every situation.
Bug Fixes
March 12, 2025
Features and Improvements
- Auxiliary Files (SCRIPT and DATA Sections): Updated the Move script command to accept labels to specify the branch and also accept a bus label instead of a bus number for the destination
- File Formats: The Limit Monitoring option for "Do not monitor radial lines and buses" is no automatically reset to unchecked when loading a new RAW or EPC file. Previously it would remain at whatever setting it had before opening the RAW or EPC file.
- File Formats: In the previous patch, features were added when loading a RAW file that were locating incorrect treatment in RAW file solutions if FixedNumBus with a mixture of Connected and Disconnected substation node statuses. This patch introduces features to automatically determine switching devices that could be closed to match the incorrect RAW file solution and prompt the user asking them if they would like us to close these switching devices.
- Oneline Diagrams: Added Region Display Styles for creating automated oneline displays from geographic Region objects.
- Transient Stability: When a vertical axis is set to ScaleMinAuto and ScaleMaxAuto the axis extremes are calculated automatically, however PowerWorld has always internally ensured that the range at least shows a variation in the 5th significant digit. A new option has been added to allow the user to specify a ScaleAutoRangeMin. This will ensure that the auto extremes calculated are enforce that (AutoMax - AutoMin) >= ScaleAutoRangeMin. If the range is less than this then the new range will be set to the average of the AutoMax and AutoMin plus/minus the ScaleAutoRangeMin/2.
NewAutoMax = (AutoMax + AutoMin)/2 + ScaleAutoRangeMin/2
NewAutoMin = (AutoMax + AutoMin)/2 - ScaleAutoRangeMin/2 - Transient Stability: When ScaleMinAuto and ScaleMaxAuto are both set to YES and the user sets a value for ScaleInc, modified so that the maximum value used for an increment will be (Max-Min)/2 so at a minimum 3 points will be labels on the vertical axis. This prevents situations such as ScaleInc being set to 0.05 when the automatically determine Max is 1.02 and Min is 1.01 which would create a Y-axis without any scale because the increment was too big.
- Oneline Diagrams: The local menu when right-clicking on a branch display object on a oneline shows the From and To bus numbers listed at the top of the menu. The "To:" was not propertly showing the To bus but was instead just repeating the From bus. This has been fixed.
Bug Fixes
March 10, 2025
Features and Improvements
- File Formats: PowerWorld has found many RAW files with FixedNumBus groupings with a mixture of Nodes with Connected and Disconnected Status. At some of these nodes with Mixed Status, there are generator, load or shunt objects that meet the following criteria (1) Terminal is at a disconnected node, (2) device status = 1, and (3) MW or Mvar injection exists. Because the terminal nodes are disconnected for these devices by substation switching devices, they can not provide injection to the system. PowerWorld has found many RAW file solutions that have these disconnected devices supplying or absorbing power. Various messages log information is now displayed when this is encountered along with recommended switching devices that can be closed to replicated the RAW file solution.
- Transient Stability: Implemented a new UEL2CPTI model, that is created when reading in the UEL2C model record in a PTI DYR file. This new model has extra model parameters compared to a UEL2C model GE DYD file -- (i) an extra 11th pair (P10, Q10) in the lookup table, (ii) an extra limit pair (VULmax/min) on the VUEL output signal, and (iii) an extra parameter (Quad) that allows the lookup table to be used as mirrored around the MVAR axis when MW values are negative. This extra parameters are read/written from the text formats, and the are fully implemented during the dynamic simulation.
March 7, 2025
Features and Improvements
- Bus View and Substation View Onelines: Added a new visualization for Bus View to show "Consolidate FixedNumBus Splits" which will generally show FixedNumBus groupings but will automatically split up those groupings if there are multiple Superbus within the group. This ensures that the user can always see open breakers that have split the FixedNumBus
- Bus View and Substation View Onelines: Modified the "Consolidated Superbus" BusView to highlight other SuperBus which would be part of the Superbus if switching devices were closed or other things preventing consolidation were ignored.
- Bus View and Substation View Onelines: Modified the "Consolidated FixedNumBus" BusView to visualize the splits created by the open switching devices.
- Case Information Displays: A new field was added to a Bus, Gen, Load, and Shunt object called Solution\Status FixedNumBus. Shows either Disconnected, Connected, Mixed, Connected2, Mixed2, and so on. If all buses in the FixedNumBus are Disconnected it will show Disconnected. If all are Connected, then it will show Connected followed by the number of unique SuperBus that are inside the FixedNum Bus if more than 2. If there is are both Connected and Disconnected buses, then it will say Mixed.
- File Formats: When loading in other file formats, PowerWorld would set a bus' voltage could be set equal to another bus if it was radial to the other bus and also had no load, generation, or shunts. This improved solution convergence is cases written in other file formats. A message log is now written indicating this is happening.
- Transient Stability: Added support to read and write to a dyd file for the transient models OEL4C and OEL5C.
- Transient Stability: On generator dialog when adding a model the dialog which appears had the "folder icon" and the "blue dot icon" flipped. This has been fixed
- Transient Stability: Access violation bug when using certain system or groups transient model (like system wide WSCC load model) and opening a table of the transient models in the Model Explorer. Now the access violation will not occur.
- User Interface Dialogs: Changes were made to the look and feel of the selected text in the Message Log in Simulator 24. These changes caused the font size of the message log to be ignored and unchangeable. This has been fixed.