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Seeing through switchgear

Extend maintenance cycles with a safer, faster, and lower cost diagnostic option


ABB was asked to perform radiographic inspections of eight ABB breakers for a Pacific Northwest utility in the fall of 2006. Shortly before the inspection, the utility had removed a Westinghouse 262SFA breaker from service. An inspection of the removed breaker revealed that the orifice on one contact was broken and that the guide rings from four others had become detached and were lying at the bottom of the tank.

This situation posed the possibility of a catastrophic circuit breaker failure. Increasing the risk was the fact that the broken part turned out not to be an OEM 1 component but a reverse engineered non-OEM one (ABB took over the transmission and distribution activities of Westinghouse in 1989 and continues to supplies OEM parts).

Idaho Power owned 7 of these breakers. It was estimated that by traditional method it would take 1 week for at least 3 people to inspect each breaker assuming the factors such as the weather cooperated, plus man lifts, SF6 reclaimers, etc. The other option was computed radiography. Using radiography, the seven breakers were inspected in approximately 5 days (including travel time between stations and set-up time after arrival) as opposed to 7 weeks.

The parts were on hand before the breaker was taken out of service .Only the pole that had a problem was disassembled. The outage was scheduled for when the parts were on site and the system would allow the outage without any “de-rates”. The risk to the equipment was greatly reduced as no disassemble and reassembly was required. . This operation saved the customer $60,000 with respect to traditional internal inspections.

Hence, when coupled with traditional external diagnostic testing, radiography can eliminate unnecessary or invasive internal inspections and maintenance, thus significantly decreasing maintenance costs and improving the reliability of the breaker. The use of Radiography for the diagnostic testing of SF6 circuit breakers allows ABB to economically deploy a well-proven technology in a completely new way!

Main data

Country United States of America
Customer Pacific Northwest utility, Idaho
Scope of supply Radiography as a diagnostic tool for preventative breaker maintenance
Inspection scope Use of radiography to examine eight of Westinghouse 362 SFA breakers
Year of radiographic inspection October, 2006
Radiographic inspection results
over $60,000 was saved when compared to the cost of traditional internal maintenance inspections



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