Software Patches

December 4, 2018

Features and Improvements

  • File Formats: Committing changes to the relay data import tool. The tool has been significantly updated to read relay data for multiple relays from an ASPEN RAT file.
  • Integrated Topology Processing (ITP): Sped up routine related to calculating island information. This speed up will be especially noticeable in full topology cases when validating the case, solving the power flow, and deconsolidation because during these process information about the state of the islands is stored for the power flow solution.
  • Bug Fixes

    • Optimal Power Flow (OPF): When allowing loads to be controls as part of the OPF, loads will not be a control if their voltage is below the Minimum Per Unit Voltage for Constant Power Loads threshold and the nominal constant power load is non-zero or their voltage is below the Minimum Per Unit Voltage for Constant Current Loads threshold and their nominal constant current load is non-zero.
    • Power Flow Solution: It was possible for angle smoothing to fail after closing in a line if the closure was connecting previously dead buses. An error would be in the log indicating that angle smoothing failed. This situation is now handled and angle smoothing should not fail.
    • Power Flow Solution: It is possible that a connected bus ends up with a zero voltage. This could cause access violations and/or zero determinant errors. If buses like this are encountered, the zero voltage will be set to a very small voltage instead when filling the Jacobian. This will eliminate fatal errors that are not useful to the user, but the zero voltages should still stand out as being a problem with the case that the user should try to fix.
    • Transient Stability: Modified svsmo3 so it will not immediately respond to small changes in voltage change when the shunt is at a limit and the voltage changes a small amount.
    • Transient Stability: When initializing the distribution equivalent model in transient stability, various models base the MVABase of the feeder and transformer on a value proportional to the Load MW. This caused a problem when a small load (say 5 MW) was coupled with a large Distributed Generation MW (say 50 MW). The feeder/transformer would then have impedances based on a 5 MW value which is inappropriate and would result in solution problems because the feeder/transformer impedances were much too large. This has been fixed by basing the MVABase on the maximum value of either Abs(LoadMW) or Abs(DistMW) instead.
    • User Interface Dialogs: Fixed a bug in the Shortcut Definition Dialog. After creating a new short-cut the edit box for the oneline file location and other edit boxes was not properly re-activated.