Software Patches

June 2, 2016

Bug Fixes

  • Transient Stability: Modified the svsmo1, svsmo2, and svsmo3 models so that if the slow B control is not active in the power flow input data, then we ignore the Vrefmax and Vrefmin values in the stability model. Vrefmax and Vrefmin are really part of the slow B control in the power flow, so if they're not active in the power flow model, it makes sense that they also not be active in the stability model.
  • Transient Stability: Simulator had previously been treating the input to PSS2B when code 3 used as as Pelec - PelecInitial. We have found that it is intended to be Pelec directly instead. This had never mattered previously because the first block on PSS2B was a washout block and thus any constant input offset was completely removed anyway. However, PSS2B has input limits Vs2max and Vs2min so this distinction would matter if these limits were specified. PowerWorld had never seen a model with input limits that would be active however, so this had never been noticed. This has now been fixed.