Oil circuit re-closers, OCRs in electric distribution lingo, are the pole-mounted devices that keep Buckeye Rural Electric Cooperative power lines humming during normal times and safely interrupt the flow of electrons during emergencies.
Rated by amperage and fault current, OCRs are like emergency valves. When a tree limb brushes a power line or an unlucky squirrel makes contact, the OCR detects the fault and acts in a millisecond.
Current is interrupted momentarily – what you might see as a “blink” – in an action known as an “operation.” This allows the fault to clear without the risk of burning down a line and creating an extended power outage.
OCRs number in the multiple hundreds on the BREC system. Because of rural terrain and heavy vegetation, these circuit breakers are invaluable to the reliable and safe operation of the cooperative’s 2,600 miles of line.
Maintaining OCRs is crucial. Repeated operations cause the mineral oil inside the pot-like containers to break down, becoming thick and eventually slowing operations or malfunctioning out of hand.
A failed OCR could mean damage to the system or a safety threat.
BREC relies on a Kansas-based firm, Solomon Electric, to perform on-site inspections of OCRs. Solomon brought its mobile test lab to Rio Grande headquarters in the fall, where line crews started delivering OCRs for testing and rehabilitation.
“If the mineral oil is in poor shape, it will be drained and the OCR refilled,” explained BREC Operations Manager Marvin Ours.
“Sometimes, the OCRs are damaged by lightning strikes or heavier faults. If possible, we will repair these units and put them back in the field. Solomon takes care of this for us, too.”
The inside of an OCR is filled with plumbing, coils, wires, and mineral oil. The traveling test lab is equipped with material to rebuild units not heavily damaged. Others might have to be retired, but the goal is to extend the use of OCRs through regular maintenance.
“We brought in over 100 OCRs and rehabilitated 90 of them,” Ours said. “They’ll be sent back into the field. The testing and tune-up sure beat buying new units. Plus, we are involved in preventative maintenance that will help reduce outage time.”
Ours’ goal is to bring Solomon Electric’s mobile lab to BREC on an annual basis in order to test and repair OCRs.
“There are a lot of OCRs out there on our system. I’d like to see us get on a regular cycle on maintenance. At least every five years, we should cover the system and test each unit in the field.”
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