Software Patches

May 31, 2018

Features and Improvements

  • Auxiliary Files (SCRIPT and DATA Sections): Added the ability to delete named system states, both through the GUI and with a new script command "DeleteState" which takes the same parameters as "RestoreState". If the name "All" is provided for the named state to delete, all named states will be cleared.
  • File Formats: When loading an Areva hdbexport CSV file, Simulator reads the BS record fields MMINJMW and MMINJMR and places those as GShunt and BShunt values at one of the Simulator Bus records. The Simulator Bus records correspond to the ND records in the hdbexport CSV file. These mismatches represent the mismatch from the optimal state estimation solution. Previously Simulator would arbitrarily assign the BShunt and GShunt values to the Bus with the lowest bus number. This has been changed now with the goal of keeping these injections connected to the system as much as possible even as devices are opened and closed from this base model. To achieve this, Simulator has a preference that the mismatch be assigned to a bus that has the highest number of in-service branches and DC devices dconnected to it. As a tie-breaker after that device count, the preference is for the following type of devices (in order) to be connected to the bus:
    (1)DC, VSC, Multiterminal DC, (2)Series Caps, (3)Transformers, (4)Lines, (5)ZBR, (6)Breaker, (7)Load Break Disconnect, (8)Fuse, (9)Ground Disconnect.
    Overriding all these preferences however, Simulator will also discourage buses connected to
    (1)Switched Shunts, (2)Generators or (3)Loads
    The goal here is to not assign the MW/Mvar mismatch to a bus that could be commonly taken out of service when isolating another device in the system.
  • File Formats: When reading an hdbexport CSV file and performing a translation of the DC system into PowerWorld Simulator's data structures, Simulator will now search for generation (UN records) inside the DC system and translate those generators directly to the AC system terminal bus that is kept after performing the translation. This helps translate some VSC DC lines that are being modeled approximately in the hdbexport file by customers who add a synchronous condenser (UN record) inside the DC system.
  • Scheduled Actions: Disabled mouse-wheel scrolling over the Scheduled Actions active time window.
  • Bug Fixes

    • Case Information Displays: The fields for a bus related to show the switched shunt MW and Mvar totals will show a blank value if no switched shunts exist at the bus. This typically would work correctly, however if a shunt was added to a bus and then deleted or moved, the bus would continue to show a value for the shunt totals of 0.0 instead of a blank. This has been fixed.
    • Power Flow Solution: After a failed power flow solution occurred in which the multi-terminal DC line solution changed the voltage-controlling converter due to depressed AC voltages, the system may not accurately represent the rectifier and inverter converters. The solution was failed regardless, but this caused some confusion as to why it failed to solve. This has been fixed so that the converters show the appropriate settings, although the solution will remain failed.
    • Power Flow Solution: Adding the recent new features regarding "Close Breakers to Energize Switched Shunts" has exposed a problem of coordinating with the BShunt and GShunt admittance at a bus when opening and closing breakers related to the switched shunt. BShunt and GShunt at a bus are an artifact of the mismatch read in from a state estimation solution. This should impact the automatic opening/closing of shunts and has been fixed.
    • Transient Stability: Fixed error with reading/write the model REGCA1 from the DYR file. The REGCA1 model has the parameter Accel as the last parameter in the parameter list. Simulator was reading that parameter in our parameter Xe which represents an additional source impedance for the model. This was incorrect. It has been fixed so that when reading the REGCA1 model we will ignore the Accel parameter as we do not use nor store it and when writing out the REGCA model we will always write an Accel value of 0.8.