WILLMAR – A tree branch fell on overhead power lines on Sunday, leaving 1,688 Willmar municipal utility customers without power for an hour. The branch fell on power lines shortly before 4 p.m. along Willmar Avenue Southwest.
The protection systems momentarily de-energized and energized part of the distribution network. However, the branch got caught in the power lines and the circuit was automatically de-energized, Willmar Municipal Utilities Electrical Engineer Jeron Smith told the Municipal Utilities Commission on Monday.
“The way our protection systems work is that they interrupt very quickly, so they cut the power and then turn it back on very quickly, and our customers can recognize it as a blink of an eye,” said Smith. “The point of this is that if there’s an animal, like a squirrel or a branch on the line, as long as it’s energized, it’s going to stay up there and it’s going to burn. But, if we interrupt very quickly, he will fall and we can restore the power.”
Willmar Municipal Utilities crews restored power after locating and removing the branch.
“We have a very thorough vegetation management program where we prune trees to reduce power line vegetation, but that’s a design for rodents and the wind blowing the tree branch over it,” said Smith continued, noting that this does not prevent branches from breaking and falling into the line. “If we were to try to do that – in this case the tree branch was almost 15 feet above the lines – any houses or properties near an overhead power line route, there would only have bare trees. That wouldn’t be very helpful to our customers.”
More than 85% of Willmar Municipal Utilities’ lines run underground for its distribution system, which is the best way to prevent this type of outage, according to Smith.