CONSUMERS ENERGY CO

Incident Narrative

ON SATURDAY, MAY 2, 2015 AT APPROXIMATELY 16:47 AN ABOVE-GRADE 10"" HIGH PRESSURE DISTRIBUTION EMERGENCY VALVE ASSEMBLY WAS STRUCK BY A FARMER OPERATING CULTIVATION EQUIPMENT IN A FIELD NEAR 4487 E. M-71, CORUNNA, SHIAWASSEE COUNTY, MICHIGAN. A 2"" THREADED NIPPLE WAS TORN OFF AS A RESULT OF THE DAMAGE, CAUSING BLOWING GAS. CONSUMERS ENERGY PERSONNEL ARRIVED ON SITE AT APPROXIMATELY 17:17 TO ADDRESS THE IMMEDIATE PUBLIC SAFETY HAZARD, SECURE THE SITE, ASSESS DAMAGE TO COMPANY FACILITIES, AND DETERMINE NEXT STEPS. LOCAL POLICE AND AND FIRE PERSONNEL BLOCKED TRAFFIC IN BOTH DIRECTION ON HIGHWAY E. M-71, AND APPROXIMATELY 60 RESIDENCES WERE EVACUATED. TEMPORARY SHELTER FOR WAS PROVIDED TO EVACUATED RESIDENTS. BASED ON AN ANALYSIS OF REPAIR OPTIONS AND POTENTIAL SERVICE INTERRUPTIONS FROM ISOLATING THE DAMAGED SECTION, A PRESSURE REDUCTION WAS PERFORMED TO TAKE THE AFFECTED SEGMENT FROM 315 PSIG TO 150 PSIG. THE GRADUAL PRESSURE REDUCTION ALLOWED SERVICE TO BE MAINTAINED TO SEVERAL THOUSAND CUSTOMERS IN PREPARATION FOR VALVING OPERATION. THE PRESSURE REDUCTION WAS COMPLETED AT 00:28 HOURS ON MAY 3. A REVISED RESPONSE PLAN WAS DEVELOPED AT 4:00 HOURS TO FURTHER REDUCE SERVICE INTERRUPTIONS BY BACKFEEDING THE DOWNSTREAM 60 PSIG (MEDIUM PRESSURE) SYSTEM FROM TWO ADJACENT SYSTEMS. AT APPROXIMATELY 12:00 HOURS ON MAY 3, PRESSURE ON THE DAMAGED HIGH PRESSURE SYSTEM WAS FURTHER REDUCED TO BELOW 15 PSIG, ALLOWING CONSUMERS ENERGY PERSONNEL TO REPLACE THE DAMAGED THREADED VALVE ASSEMBLY AND COMPLETE REPAIRS TO THE DAMAGED FACILITY. AT 14:45 ON MAY 3, BLOWING GAS WAS STOPPED FOR COMPLETION OF FINAL REPAIRS. REPAIRS WERE COMPLETED AND NORMAL OPERATION WAS RESTORED AT 16:00.