Blinking clocks, OCRs and us
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.
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
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
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.