Software Patches

March 18, 2024

Features and Improvements

  • Time Step Simulation: Changed Solar PFW model to include a parameter for the Inverter Loading Ratio. Also, reduced the assumed optical depth in the irradiation calcuation, which causes more irradiation when the sun is lower in the sky.
  • User Interface Dialogs: On the Transformer Parameters dialog the ESC key will now close the dialog without saving changes.
  • Bug Fixes

    • Distributed Computation: Fixed error in showing Custom Expression results which do not have a valid expression string specified. An access violation could occur. This was noticed due to an access violation occurring in the distributed Transient Stability simulations.
    • Optimal Power Flow (OPF): During an OPF or SCOPF solution (either AC or DC method), fast start generators (commitment and/or decommitment) were not being dispatched correctly when the MinMW of these generators is more than zero. This bug was inadvertently introduced on 9/27/22. Possibly affected users would be those with OPF and SCOPF cases with fast start generators like these, and they might have noticed odd generator dispatches and violations during an OPF solution. It is possible to not have noticed this bug, especially if the existing state of the system did not require the commitment or decommitment of fast start generators during OPF or SCOPF.
    • Security Constrained OPF (SCOPF) Tool: This bug fix addresses the incorrect dispatch of some generators and loads that are available for control during a SCOPF solution (either AC or DC mode). An example of this is when a OPEN generator action is part of contingency. A branch limit violation during that contingency would then (previously) redispatch the base case MW of that generator to alleviate the contingency limit violation. However, this was an erroneous redispatch because the generator would be OPEN during that contingency and hence the violation would not actually alleviate. More SCOPF outer loop iterations would worsen this skewed dispatch, and ultimately lead to "SCOPF Aborted with Error = Power Flow Did Not Converge".