CONSUMERS ENERGY CO — Gas transmission and gathering — incident on 2016-08-10

Gas transmission and gathering incident in ARMADA, MACOMB County, MI. Reported cause: INCORRECT OPERATION. Reported consequences: 0 fatalities, 0 injuries, 18000 NATURAL GAS released, $0 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20160073.

Operator ID: 2748.

Reported incident date: 8/10/2016 23:32.

Location detail: GV-007

Cause detail: OTHER INCORRECT OPERATION

Cause detail: ON AUGUST 10, 2016 AT APPROXIMATELY 22:43 CONSUMERS ENERGY RAY COMPRESSOR STATION EXPERIENCED AN EVENT WHEREBY POWER SUPPLIED BY THE UTILITY SUPPLIER WAS BELOW NORMAL LEVELS. THE CONTROL SYSTEM RECOGNIZED A UTILITY SOURCE PHASE SEQUENCE LOSS AS WELL AS A STATION UNINTERRUPTIBLE POWER SUPPLY (UPS) ALARM. AT APPROXIMATELY 22:44, THE COMMERCIAL UTILITY BREAKERS TRIPPED OPEN AND PLANT 3 EMERGENCY SYSTEM TRANSFERRED POWER FROM THE UTILITY OVER TO GENERATOR 3-00-01. THE SYSTEM ATTEMPTED TO TRANSFER POWER TO THE C2-7 GENERATOR SET FOR PLANTS 1 AND 2; HOWEVER, THE SYSTEM DID NOT START AND PLANTS 1, 2 AND THE CONTROL ROOM REMAINED ON UPS POWER. AT APPROXIMATELY 22:44, UTILITY POWER AT THE STATION WAS RESTORED TO ACCEPTABLE LEVELS ACROSS ALL THREE LEGS, AB, BC AND CA. PLANT 3 TRANSFERRED BACK TO UTILITY POWER, HOWEVER, PLANT 1, 2 AND THE CONTROL ROOM REMAINED ON UPS POWER. AT APPROXIMATELY 22:52, UNIT 2-7 INITIATED IT'S SHUTDOWN SEQUENCE DUE TO HIGH CRANKCASE OIL TEMPERATURE, HIGH JACKET WATER TEMPERATURE, LOW ENGINE LUBE OIL PRESSURE AND LOW TURBOCHARGER OIL PRESSURE ALARMS. AT APPROXIMATELY 23:32 THE 2-7 UPS WAS DEPLETED WHICH SUPPLIED POWER TO VENT VALVE GV-007. VENT VALVE GV-007 FAILED OPEN, AS DESIGNED IN THE EVENT OF A POWER LOSS, RESULTING IN A RELEASE OF NATURAL GAS INTO THE ATMOSPHERE. THE ON-CALL OPERATOR ARRIVED AT THE LOCATION ON AUGUST 11, 2016 AT APPROXIMATELY 00:06. AT APPROXIMATELY 00:14 THE ON-CALL OPERATOR REPORTED VENTING GAS AT THE THE SOUTHWEST CORNER OF THE PLANT, VALIDATED THE VENTING GAS WAS COMING FROM PLANT 2 AT APPROXIMATELY 00:20. AT APPROXIMATELY 00:28 A PLANT 2 FIREGATE OPERATION WAS INITIATED AND VENTING GAS WAS STOPPED AT APPROXIMATELY 00:33. THE ON-SITE TEAM BEGAN INVESTIGATING THE CAUSE OF THE VENT VALVE OPENING AND GATHERING DATA. IT WAS DETERMINED THAT GENERATOR 2-7 CONTROL PANEL WAS IN THE "OFF" POSITION. THE CONTROL PANEL IN THE "OFF" POSITION PREVENTS AUTOMATIC OPERATION OF THE UNIT. ON AUGUST 11, 2016 AFTER COMPLETING THE INVESTIGATION, PLANT 2 WAS PLACED BACK INTO SERVICE AT APPROXIMATELY 16:00.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: INCORRECT OPERATION — OTHER INCORRECT OPERATION.

PHMSA indexed costs: $56,218 reported total cost, $58,720.452 in 1984 dollars, $73,328.574 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.