Power outage Sunday in Willmar caused by fallen tree branch
A broken tree branch that fell on the power lines in Willmar caused an hour-long power outage for 1,688 Willmar Municipal Utilities customers.
WILLMAR — A tree branch fell on overhead power lines Sunday, leaving 1,688 Willmar Municipal Utilities customers without power for an hour. The branch fell onto power lines a little before 4 p.m. along Willmar Avenue Southwest.
Protection systems momentarily de-energized and re-energized a portion of the distribution grid. However, the branch remained 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 they do a really quick interruption, so they cut the power and then turn it on really fast, and our customers may recognize that as a blink of the lights," Smith said. "The purpose of that is if there is an animal, like a squirrel, or a branch on the line, as long as its energized, it's going to stay up there and it's going to burn. But, if we interrupt it real quick, it will fall free and we can get the power back on."
Willmar Municipal Utilities crews restored power after the branch was located and removed.
"We do have a very thorough vegetation management program where we trim trees to cut back the vegetation from the power line, but that's a design for rodents and wind blowing the tree branch into them," Smith continued, noting it doesn't 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 just be bare trees. It wouldn't be very helpful to our customers."
More than 85% of Willmar Municipal Utilities lines are underground for its distribution system, which is the best way to prevent this type of outage, according to Smith.