Software Patches

September 19, 2014

Features and Improvements

  • Power Flow Solution: Changed the way the 2-terminal DC line firing angle and tap control are handled when GammaMin = GammaMax. Under other situations once the maximum tap value is reached and the DC voltage is still above the desired setpoint, then Simulator will calculate a firing angle that exceeds GammaMax. This has been changed now so that if GammaMin=GammaMax, then the firing angle will remain constant and instead the DC voltage setpoint enforcement is abandoned and the DC voltage will be higher than the setpoint. When this occurs a prominently highlighted message will be written to the log. This change in control feature was added primarily to match the treatment in several ERAG/MMWG, PJM, and MISO cases we have seen recently which have some erroneous input data.
  • Transient Stability: modified the WT1G1, WT2G1, WT3G1, WT3G2, and WT4G1 wind turbine models so that they ignore any implicit step-up transformers.
  • Transient Stability: Modified reading of a GNET.idv file to allow multiple gnet sections in the same file to be read.
  • Transient Stability: added other field for CMPLDW to show the "Fraction not tripped on under voltage" for the Type 3 motors.
  • Bug Fixes

    • File Formats: When reading the hdbexport CSV files, modified reading of XF records so that if ID_XFMR values are not read at all then no three-winding transformers are created.
    • Transient Stability: Fixed a bug that was causing an access violation when auto inserting and deleting previous contingencies
    • Transient Stability: Treatment for handling low voltages for GEWTG was missing and was added.
    • Transient Stability: fixed error in the PSS3B stabilizer. Using this stabilizer was causing an error when running a transient stability simulation
    • Transient Stability: A bug was occurring when opening a generator which had a COMP or other voltage compensator model assigned to it
    • Transient Stability: fixed error in displaying data for IVOEX exciter in the case information displays. The Max/Min values were shown as blanks.
    • Transient Stability: When one of the blocks on either an IVOEX or EXIVO exciter were configured such that A2=0, A4=0 or A6=0, then the block becomes a PI controller. The initialization of the PI controller was not done properly and has now been fixed.
    • Transient Stability: fixed initialization of the CompCC model so that the order in which models are initialized does not prevent matter. CompCC is assigned to a generator record but then refers to a second generator. Previously the generator with the CompCC model had to be initialized BEFORE the second generator. The software now handles the ordering.
    • Transient Stability: Fixed error with using a wind turbine model with an implicit step-up transformer. The voltage measurement was not working properly and is now fixed.
    • Transient Stability: modified EXAC1 and EXAC1A to include subinterval integration when Ta=0 AND Tb=0.
    • Transient Stability: modified ESAC5A to include subinterval integration when Ka/Ta is large.
    • Transient Stability: fixed error in the use of the WT2E power slip curve.
    • Transient Stability: Fixed error that only occurred when tripping a portion of Motor A, B, C, or D if it was a double-cage motor model inside of a CMPLDW or CMPLDWNF model. Error was an improper calculation of derivative of the rotor speed.
    • Transient Stability: Modified handling of LD1PAC and thus CMPLDW at extremely low voltages (below 0.2 per unit) to better handle them in the algebraic network boundary solutions.
    • Transient Stability: Modified the handling of validation for very low Tppo values for the CMPLDW and CMPLDWNF model.
    • Transient Stability: When loading in a transient plot series from an AUX file which referred to a PlayIn signal the plot series was not created. This has been fixed.