Software Patches

August 26, 2016

Features and Improvements

  • File Formats: Fixed the reading of the ITEMS_LNAMP fields to appropriately set whether to monitor AMP limits
  • Power Flow Solution: SVC type switched shunts which had a minimum and maximum control range of 0.0 and 0.0 were being treated as though the control range was infinite (limits ignored). This has been changed so that the SVC will instead leave the min/max values as 0.0 and just never move instead.
  • Power Flow Solution: When opening an EPC file and solving the power flow immediately sometimes voltage controls such as tap ratios moved when it did not appear they needed to. The final solution still met the control requirements, but to the user it did not appear anything should move. This was caused when an svsmo1 or svsmo3 type SVC was initially at one of its maximum or mininimum control limits. The initial power flow solution was not properly catching when the SVC started at one of its control limits. This was causing the SVC to initially move to regulate voltage in the inner power flow solution (treated as PV bus). Then in the voltage control loop the SVC would realize it was at a limit and properly enforce the limit. While this was silly, the SVC itself ended up where it should. However moving of the system around may cause other voltage controls such as transformer tap ratios to change during the initial inner power flow solution and then move again after the SVC limit was enforced. All this moving around could give you a slightly different solution than expected. This has been fixed.
  • User Interface Dialogs: When defining a very large number of Transfer Directions for use in the multi-direction PTDF calculation, Simulator makes a new field available on a branch (and interface) for every transfer direction. When building a TreeView or a drop-down box in the user interface for choosing a field however this could make for a huge number of entries making the user interface extremely slow. One user reported waiting a couple minutes for the Model Explorer to open. This was due to about 24,000 transfer directions being defined. To fix this, TreeViews and drop-down boxes will never show more than 1000 of these dynamically created fields. A user may still use these fields using Auxiliary File scripting as well as via SimAuto, but they will not see them in the field choosers in the user interface. Note that these fields are already automatically added to tables where appropriate (like on the Multi-Direction PTDF calculation table). This change will also improve performance when viewing a list of fields if Multi-Element TLR calculations have been done with more than 1000 elements.
  • Bug Fixes

    • File Formats: When loading an EPC file, we now automatically use the advanced solution option to "Model Phase Shifters as Discrete Controls" as this represents how EPC files treat phase shifters.
    • File Formats: When loading an RAW file, we now automatically disable the advanced solution option to "Model Phase Shifters as Discrete Controls" as this represents how RAW files treat phase shifters.
    • Power Flow Solution: Discrete phase shifters with too narrow of a MW regulation range will often not move even when a control error still exists. This is because moving to the next tap settings will jump all the way across the MW regulation range and end up further away. Simulator has always written log messages about this, but they were repeated for every solution. The log has been changed so that this informational message is only written once now.
    • Transient Stability: Added the ability to look at the Area, Zone, Balancing Authority, Substation, and Owner information with all the various transient stability dynamic models.