Software Patches

May 11, 2016

Bug Fixes

  • Fault Analysis: Fixed a bug when building the positive and negative sequence admittance matrices. If there were 2 or more parallel transformers in the model, the off-diagonal elements in the admittance matrices were not correctly combining all of the transformer admittances, but rather was only putting one of the transformer admittances in the off-diagonal and was ignoring the rest of the parallel transformers.
  • Transient Stability: When a negative ThetaMin value is specified for wind pitch controller WT3P, WT3P1, or WTGPT_A model, this can be used by the WT3T/WT3T1/WTGT_A model to determine it's Theta0 value. In this situation however, the initial output of the WT3P/WT3P1/WTGPT_A model could be either ThetaMin or 0.0 (zero). Both will result in the appropriate initial output from the Aerodynamic model. Previously Simulator was initializing this value to ThetaMin which appeared OK, but this equilibrium point is an unstable equalibrium. Simulator has been changed so that when ThetaMin is negative, the initialized output of the pitch controller is set to 0.0 (zero).