Rural Missouri Magazine

Blinking clocks, OCRs and us

by Frank Stork

The other morning I filled and started our automatic coffee maker. After spending a few minutes outside enjoying the early morning sounds and smells, I eagerly returned to the house for my first cup.

Instead of finding hot coffee freshly brewed, I found a blinking digital clock on Mr. Coffee and a pot half full of cool, dark water. The electric power had tripped off while I was outside.

Seeing that the electricity was already back on, I reset and waited for Mr. Coffee to complete his very important work. While waiting, I had time to think about my negative reaction to the blinking clock.

We react that way because we know the electric power tripped off. Even though the lights come right back on, the brief outage will require us to reset clocks. We consider that an inconvenience.

If the flow of electricity to our house was interrupted, how did it come back on so quickly? The short answer is because a huge investment has been made in our electric power delivery system to restore power almost instantly after a line fault occurs.

Just as the electrical system in our house is protected by circuit breakers or fuses, so is the power line that brings electricity to our house.

The devices protecting our power lines are called Oil Circuit Reclosers (OCRs). They are a lot smarter than the circuit breakers or fuses in our homes. They are smarter because they automatically reset themselves if the problem that caused them to open is no longer present.

Problems that cause a line to trip off (fault) include animals or birds getting into the line. A snake will crawl atop a pole to inspect a bird nest. Woodpeckers love working at the top of poles. Squirrels often climb poles just for fun.

If a bird, snake or squirrel get into the line and cause a fault, they will usually fall to the ground. When they fall the problem is gone and the OCR will automatically close the circuit. The flow of electricity will be restored in just a few seconds. A few years ago, that same outage might have lasted hours because crews would have to come out to replace a line fuse.

Other causes of power interruptions can include: a branch falling from a tree, wind slapping the lines together, a cow or horse scratching its back on a guywire, summer storms or a vehicle running into a pole. Because so many things can cause a fault, it's a wonder we don't have more temporary line outages.

When we see a clock blinking, we can think about the OCR that was smart enough to reset itself. Instead of calling the cooperative and saying there is something wrong, we might want to call and say the OCR protecting our power line is working just fine.

Stork was executive vice president of the Association of Missouri Electric Cooperatives and a member of Three Rivers Electric Co-op.

Rural Missouri | June 2020 Issue

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