CONSUMERS ENERGY CO

Incident Narrative

ON NOVEMBER 21, 2022, AT APPROXIMATELY 06:00 HOURS, A STATION MECHANIC REPORTING TO WORK AT THE CONSUMERS ENERGY'S FREEDOM COMPRESSOR STATION OBSERVED GAS BLOWING AT/NEAR THE CONDENSATE STORAGE TANK. FREEDOM COMPRESSOR STATION IS LOCATED AT 12201 E. PLEASANT LAKE ROAD, MANCHESTER, (WASHTENAW COUNTY) MICHIGAN. THE EMPLOYEE RESPONDED BY UTILIZING ISOLATION VALVE (30SDV-012) TO STOP THE GAS FROM BLOWING AND BEGAN A PRELIMINARY INVESTIGATION TO DETERMINE THE CAUSE OF THE GAS RELEASE. A REVIEW OF THE SECURITY FOOTAGE AND CONFIRMATION OF HISTORIAN DATA DETERMINED THE RELEASE BEGAN ON SUNDAY, NOVEMBER 20, 2022, AT APPROXIMATELY 05:48 HOURS. THE INITIAL INVESTIGATION ON NOVEMBER 21, 2022 DETERMINED THE FILTER SEPARATOR DUMP VALVE (30GV-528) DID NOT CLOSE AFTER THE CONDENSATE DUMP OPERATION AND ALLOWED GAS TO FLOW FREELY FROM THE FILTER-SEPARATOR TO THE CONDENSATE STORAGE TANK AND RELEASE TO ATMOSPHERE. CONSUMERS ENERGY PERSONNEL INITIATED AN ABNORMAL EQUIPMENT ALIGNMENT/CONFIGURATION REQUEST (AEC) TO ISOLATE THE FILTER-SEPARATOR CONDENSATE SYSTEM TO ALLOW FOR MANUAL OPERATION. FURTHER INVESTIGATION DETERMINED THE ROOT CAUSE OF THE RELEASE WAS DUE TO THE FILTER SEPARATOR SOUTH SUMP LEVEL CONTROLLER (LC_3001500). THE LEVEL CONTROLLER SENT A PNEUMATIC SIGNAL TO THE DUMP VALVE WHICH OPENED THE VALVE TO INITIATE THE CONDENSATE DUMP PROCESS. AFTER THE DUMP OPERATION WAS COMPLETE, THE SIGNAL TO CLOSE THE VALVE WAS NOT INITIATED (REMOVED) CAUSING THE DUMP VALVE TO REMAIN OPEN. ON DECEMBER 7, 2022, CONSUMERS ENERGY (CE) PERSONNEL MET WITH THE LOCAL MAGNETROL LEVEL CONTROLLER SALES ENGINEER TO TROUBLESHOOT THE LEVEL CONTROLLER OPERATION. DURING THE INVESTIGATION IT WAS DISCOVERED THE LEVEL ADJUSTMENT KNOB WAS SET AT 1 WHICH WAS LOWER THAN RECOMMENDED FOR THIS OPERATION. STATION PERSONNEL PROCEEDED TO INCREASE THE LEVEL CONTROL SET POINT WHILE MONITORING SYSTEM RESPONSE. AFTER ADJUSTING THE LEVEL TO A SET POINT OF 5, WHICH WAS DETERMINED TO BE AN ACCEPTABLE LEVEL SET POINT FOR OPERATION. CE PERSONNEL WILL CONTINUE TO EVALUATING GAS COMPRESSION STATION LEVEL CONTROLLERS AND GAS CONTROL NOTIFICATION METHODS TO ALARM IN THE EVENT OF GAS RELEASE ASSOCIATED WITH PNEUMATIC LEVEL CONTROL DEVICES. THE UNIT WILL REMAIN IN BY-PASS MODE UNTIL THE EVALUATION IS COMPLETED AND ACTIONS TO MITIGATE ARE IMPLEMENTED. THE EVALUATION OF THE LEVEL CONTROLLER AND GAS CONTROL NOTIFICATION METHODS AT THE FREEDOM COMPRESSOR STATION WAS COMPLETED. AS A RESULT, LOW LEVEL LIQUID ALARMS AS WELL AS CONDENSATE TANK ACOUSTIC MONITORING WERE IMPLEMENTED. THE AEC WAS REMOVED AND THE UNIT IS NO LONGER IN BY-PASS MODE, NORMAL OPERATION RESUMED ON JANUARY 24, 2023. CE HAS COMPLETED PROBLEM SOLVING SESSIONS REGARDING CONDENSATE DRAIN SYSTEM ALARMING AND FILTER-SEPARATOR COMMISSIONING/OPERATIONAL TESTING. LONG-TERM COUNTERMEASURES WERE GENERATED WITH A PLAN TO INCORPORATE FLEETWIDE.