BPA RAS Misoperations 11/2016, 6/19/2017 and 6/21/2017 Daniel Goodrich To WECC OPAS August 22, 2017

11/21/2016 Pinched wire caused DC ground

Alvey 500 Station RAS made the controller thing that both Marion-Alvey and Alvey-Dixonville were both out of service

Alvey False Line Loss Signals Because the RAS equipment falsely reported a line loss of two 500 kV lines into Alvey, the RAS controls properly dropped generation. Here is a portion of the Sequential Events Recorder: The false line loss signals are at the top. Note that it is just the “A” side, pointing to a RAS unnecessary operation. 11/21/16, 12:42:32.474 RAS AC A MARION-ALVEY LINE LOSS RECEIVED RAS AC A ALVEY-DIXONVILLE LINE LOSS RECEIVED 11/21/16, 12:42:32.500 RAS ACA AC INTERTIE DYNAMIC BRAKE ALGORITHM TRIPPED RAS AC A AC INTERTIE LOW GEN DROP ALGORITHM TRIPPED

Card Performance Characteristic Setting Performance DC Volt input threshold 84 81-83 Vdc Debounce Time 2 0.75 milliseconds The DC grounds caused brief inputs into the RAS equipment, but because it was triggering sooner than the 2 msec setting, the misoperations occurred. The above times are based on BPA testing.

Next Steps BPA Protection and RAS Design determined which Units are affected: 287 cards at about 50 sites. Replace the cards (ongoing), to be completed by the end of 2017 Increasing the input debounce time from 2 to 16 msec was completed at all critical sites by mid-August.