Investigation of Auxiliary Power Substation 95A4 Fault and Fire, Portsmouth Gaseous Diffusion Plant, March 24, 1982

摘要

On March 24, 1982, an electrical fault and resultant fire in the 480 volt Auxiliary Power Substation 95A4 at the Portsmouth Gaseous Diffusion Plant destroyed that substation. There were no personal injuries, the overall loss was limited to the Substation, and the cost of replacing the Substation with repaired and new components has been estimated at $184,000. At the time of the incident, Goodyear was involved in a project to replace the obsolete 480 volt circuit breaker of the Auxiliary Power System. This project involved the disassembly, refurishing, and reassembly of 480 volt circuit breaker carriages by Goodyear personnel. The fault occurred in a circuit breaker upgraded under this project. The investigation of this accident is reported. The evidence suggests the fault resulted from the improper assembly of an upgraded 480 volt circuit breaker. Compounding the problem and leading to the extensive damage was the failure of the transformer secondary breaker to trip open as designed and interrupt the flow of power to the substation. It is surmised that inadequate testing during preventive maintenance contributed to this condition. Additional factors which may have contributed to the accident included: no requirements for assuring the competence of the electricians who installed the circuit breakers, no specific assembly instructions to the electricians, inadequate procedure instructions, and an inadequate procedure governing operational or load testing of the breaker. (ERA citation 07:059473)