Presentation on theme: "Hydro Governor PI Controller Limits Jamie Weber PowerWorld Corporation MVWG March 19, 2014."— Presentation transcript:
Hydro Governor PI Controller Limits Jamie Weber PowerWorld Corporation MVWG March 19, 2014
2 Background Recently finished coding the H6B (H6BD) governor using documentation we received during the last MVWG meeting from John Undrill –Block Diagram –Pseudo-code of the model The psuedo-code contained a non-windup limit on the PI controller which was not shown in the block diagram
3 Block Diagram from John
5 Background I mentioned this non-windup limit to Tom Overbye Tom Overbye at University of Illinois and Mani Venkatasubramanian at Washington State have been working on a validation project as well –Validating 4 software tools –They had found similar undocumented non- windup limits on several PI controller on hydro governors in one package –Other 3 packages have implemented what is on the block diagram directly
7 Undocumented Non-Windup Limits Kp Ki/s Gmax Gmin
8 When does this matter During an large frequency drop, the PI controller will be driven UP and the gmax limits will be hit. If the frequency stays low, the gmax limit would stay active, but if the low frequency event results in a large amount of load tripping, then the frequency may go HIGH –If the PI is allowed to wind-up, then the governor will remain stuck at gmax while the PI state “unwinds” –If it was a non-windup limit it backs off immediately Basically, it matters for really big frequency excursion events
9 Should we all change these? These non-windup limits make a lot of sense – seems like they should be included PowerWorld has modified to include an option –“Include undocumented governor PI limits” Is this same thing occurring for other governor types?