PACIFIC GAS & ELECTRIC CO

Incident Narrative

ON JUNE 22, 2017 AT 1212 HOURS, A PG&E EMPLOYEE IN GAS CONTROL WAS PERFORMING A SET POINT CHANGE ON PRESSURE LIMITING STATION (PLS-6) IN PAICINES (OFF OF L-300A AT MILE POINT 436.74). AS THE OPERATOR WAS INCREASING THE SET POINT, THE RELIEF VALVE OPENED CAUSING AN UNINTENTIONAL RELEASE OF GAS. AT THAT POINT, THE OPERATOR REALIZED THAT THE SET POINT CHANGE WAS BEING PERFORMED ON A DIFFERENT STATION THAN REQUESTED. THE MAOP OF THE STATION IS 625 PSIG AND THE RELIEF VALVE OPENED AT 610 PSIG. THERE WAS NOT AN OVERPRESSURE. THE OPERATOR WAS RELIEVED OF THEIR DUTIES, TURNOVER SHIFT WAS COMPLETED, FATIGUE ASSESSMENT WAS PERFORMED AND THE EMPLOYEE WAS SENT FOR PAT TESTING. THE SET POINT AT THE STATION WAS CHANGED BACK TO ITS NORMAL SET POINT AND THE RELIEF VALVE CLOSED. THERE WERE NO INJURIES, FATALITIES OR IGNITION ASSOCIATED WITH THIS INCIDENT. PG&E TECH WAS DISPATCHED TO DO AN EVALUATION. THE TECH DETERMINED THAT THE EQUIPMENT WAS FUNCTIONING PROPERLY AND THERE WAS NO DAMAGE OBSERVED. THE ESTIMATED DURATION FOR UNINTENTIONAL RELEASE WAS 45 MINUTES. THE ESTIMATE OF GAS VOLUME THAT WAS UNINTENTIONALLY RELEASED IS 25 MMCF. THIS REPORT WAS SUBMITTED TO THE DOT (1181976/1182113) AND CPUC DUE TO SIGNIFICANT EVENT DETERMINED BY OPERATOR JUDGEMENT AND AN UNINTENTIONAL RELEASE OF GAS ABOVE 3 MMCF. THE SIGNIFICANT EVENT DETERMINED BY OPERATOR JUDGEMENT CRITERION WAS DETERMINED AT 1350 HOURS AND THE UNINTENTIONAL ESTIMATE RELEASE OF GAS ABOVE 3 MMCF CRITERION WAS DETERMINED AT 1440 HOURS.