NATURAL GAS PIPELINE CO OF AMERICA (KMI)

Incident Narrative

ON 3/09/2022, AT 05:43 NATURAL GAS PIPELINE COMPANY (NGPL) GAS CONTROL SHUT DOWN UNIT 14 REMOTELY VIA SCADA SYSTEM. SUBSEQUENTLY, NGPL OPERATIONS SPECIALIST RECEIVED AN ALARM REGARDING STATION 104, UNIT 14 AND STARTED TO INVESTIGATE THE CAUSE. AT 07:00, OPERATIONS SPECIALIST ARRIVED ON SITE TO START TROUBLESHOOTING THE ALARM. AT 08:15, AN OPERATIONS SPECIALIST #2 ARRIVED ON SITE TO SUPPORT MITIGATE THE ALARM. UPON ARRIVAL WAS ABLE TO HEAR GAS VENTING THROUGH A SILENCER ON UNIT 14. AT 09:59, OPERATIONS SPECIALIST #2 CLOSED THE VENT VALVE AND CALLED NGPL OPERATIONS SUPERVISOR. AT 11:00, OPERATIONS SUPERVISOR ARRIVED ON SITE TO INVESTIGATE THE EVENT. AT 11:45, THE EMERGENCY RESPONSE LINE (ERL) CALL COMMENCED AND DURING THE CALL, OUT OF ABUNDANCE OF CAUTION NGPL DECIDED TO REPORT THE EVENT TO THE NRC FROM A VOLUME RELEASE STANDPOINT. NGPL STARTED THE INVESTIGATION AND CONCLUDED THAT THE VOLUME RELEASED EXCEEDED THE REPORTING THRESHOLD PER THE COMPRESSOR UNIT PLC DATA. THE UNIT 14 SUCTION VALVE DID NOT CLOSE COMPLETELY AFTER SHUT DOWN, ALLOWING GAS TO VENT THROUGH THE VENT VALVE SILENCER. FURTHERMORE, THE INVESTIGATION ALSO DISCOVERED THAT THE SUCTION VALVE DID NOT CLOSE PROPERLY DUE TO THE LIMIT SWITCHES FOR THE VALVE POSITIONER AND THE SOLENOID OPERATOR. NGPL DETERMINED THAT THE LIMIT SWITCH THAT DE-ENERGIZES THE CLOSED SOLENOID ON THE VALVE OPERATOR NEEDED TO BE READJUSTED. NGPL E&C TECH READJUSTED THE LIMIT SWITCH AND CYCLED THE VALVE NUMEROUS TIMES TO ASSURE THE VALVE OPERATION. NGPL PUT UNIT 14 BACK IN SERVICE THE SAME DAY. IN ORDER TO PREVENT REOCCURRENCE NGPL WILL BE REVISING THE UNIT PLC LOGIC AND REMOVING THE LIMIT SWITCHES IN THE VALVE CONTROL CIRCUITS TO THE VALVE CONTROL SOLENOIDS TO AVOID INTERRUPTION OF THE UNIT VALVE OPEN AND CLOSE SIGNALS FROM THE PLC.