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Birds to Blame for Blinks
08/30/2021
It’s a fact of electric utility life that sometimes animals cause power outages. Usually, it’s squirrels. But this week it’s birds. Egrets, herons, cormorants and sometimes turkey vultures, as far as we can tell. And may we suggest you finish your breakfast before reading the explanation.
Entergy Arkansas has a 48-mile stretch of transmission line from Parkin to Newport. Crops are still in the fields, and in this area there are numerous bodies of water. So, there’s food to eat, water to drink, and 48 miles of power lines on which the well-fed birds like to perch and sleep.
And all is well. Until about 4 a.m. when they wake up. “You can almost set your watch by it,” said Customer Service Manager Matt Faries. The birds – thousands of them – open their eyes, stretch their wings and take flight. As they lift off, they relieve themselves on whatever lies below, including electrical components. These components include strings of ceramic and polymer insulators that keep energized wires safely separate from one another.
Layers of droppings have landed and dried on the insulators. Even that is not a problem, except in the moment when there is a new, wet deposit. This can occur with additional excrement, but often occurs during periods of high humidity early in the morning hours. At that moment – around 4 a.m. – electricity travels from one wire, through the excrement, to another wire, causing a fault on the line. This results in a protective breaker opening, causing a power outage. Fortunately, these breakers automatically attempt to re-close and re-energize the line when a fault occurs. This action sends a jolt of electricity that, as luck would have it, creates enough heat to dry the liquid waste, solving the problem. The outage lasts only a few seconds.
And even that wouldn’t be much of a problem except that on this line are some industrial customers running overnight shifts, and a blink for them causes a disruption in production. And it has happened every morning except Monday since Saturday, Aug. 21.
“This is an unusual convergence of circumstances,” Faries said. “This particular problem is very rare, but we are looking at options to mitigate the issue.”
So, what to do?
“A good rain would really help by washing the muck from the insulators,” Faries said.
Fortunately, it’s reasonable to expect that the unusual problem will go away on its own, but Entergy is taking action now.
Using drone-mounted cameras, the transmission team has identified multiple structures with excessive bird contamination. Technicians have begun replacing Insulators on one of four line sections. The new insulator strings have an “umbrella” type of insulator on the top of the string to shelter the lower insulators from the next round of droppings. Each of the remaining three line sections will be removed from service, in turn, as several additional insulators are replacing in the coming weeks.
