CONSUMERS ENERGY CO

Incident Narrative

ON JULY 5, 2020 AT APPROXIMATELY 00:13 HOURS CONSUMERS ENERGY'S RAY COMPRESSOR STATION UNIT 2-6 EXPERIENCED AN UNPLANNED SHUTDOWN RESULTING IN A NATURAL GAS FIRE. THE FACILITY IS LOCATED AT 69333 OMO ROAD, ARMADA, MICHIGAN (MACOMB COUNTY). THE FIRE WAS INITIATED IN THE TURBINE EXHAUST CHAMBER DUE TO THE INTERACTION OF OIL AND HIGH TEMPERATURE GAS. THE PRESENCE OF OIL WAS DUE TO A MECHANICAL SEAL FAILURE IN THE TURBINE.THE MECHANICAL SEAL FAILURE RESULTED IN UNSTABLE TURBINE SPEED SENDING MULTIPLE ALARMS TO THE PROGRAMMABLE LOGIC CONTROLLER (PLC). THE PLC FAILED TO CONTINUE OPERATIONS ONCE DATA POINTS REACHED A MAXIMUM OF 959 POINTS. THE PLC REGISTER FAULTED AND COULD NOT OVERWRITE THE DATA WHICH PREVENTED THE EQUIPMENT FROM SHUTTING DOWN PROPERLY. AS A RESULT OF THE PLC FAILURE, THE PROCESS GAS SUCTION, DISCHARGE AND FUEL GAS VALVES FAILED TO CLOSE. A GASKET FAILURE OCCURRED BETWEEN THE TURBINE REACTION CHAMBER AND THE TURBINE RESULTING IN A FIRE IN THE INSULATION PROVIDING A HEAT SOURCE TO IGNITE THE GAS NEAR THE EXHAUST STACK. THE FIRE WAS LIMITED TO THE 2-6 SKID AND EXHAUST STACK. THE LOCAL FIRE DEPARTMENT REPORTED TO THE SITE ENTRANCE BUT WERE NOT UTILIZED TO EXTINGUISH THE FIRE. THE STATION OPERATOR ISOLATED THE FUEL AND PROCESS GAS PIPING SYSTEMS ALLOWING THE FUEL SOURCE TO BURN OFF, EXTINGUISHING THE FIRE. CONSUMERS ENERGY'S RAY COMPRESSOR STATION (PLANT 2) REMAINS OUT OF SERVICE AND REPAIR OPTIONS ARE BEING EVALUATED. A SUPPLEMENTAL/FINAL REPORT WILL BE SUBMITTED WHEN A FINAL RESTORATION PLAN A IS DEVELOPED AND NORMAL OPERATIONS RESUMED. FOLLOWING AN EVALUATION OF OPERATIONAL NEEDS, IT WAS DETERMINED THE RAY COMPRESSOR STATION PLANT 2 UNIT 2-6 WOULD BE RETIRED. THE RETIREMENT OF THE UNIT WAS COMPLETED ON DECEMBER 8, 2020.