‘Galloping’ lines cause of power issues Monday

MARSHALL – The flickering of lights that occurred within the city of Marshall on Monday night originated from external transmission sources, a Marshall Municipal Utilities official said Tuesday, while more extensive power issues occurred in surrounding areas.

MMU Operations Manager Steve Johnson said the source of the problem for Marshall came at the Xcel-Lyon County substation about 4 miles east of town and from the East River Electric Power Cooperative substation northeast of Marshall.

“Xcel had some lines slapping together east of town due to the wind and some minor ice build-up,” Johnson said. “We had nothing go wrong within the city of Marshall.”

Johnson said the sporadic flickering in Marshall started about 7 p.m. and lasted until about 11 p.m. He said because there were no actual outages traced back to MMU, it didn’t have to dispatch any crews in Marshall.

Chris Studer, communications manager at East River Electric, which serves counties in eastern South Dakota and western and southwestern Minnesota and also feeds a power station at Southwest Minnesota State University, said the issues Monday were centered around East River high-voltage power lines that experienced significant ice build-up. That, combined with strong winds, caused the lines to slap together. Studer also said there was an equipment failure at one of its substations.

Studer said the Garvin substation was taken off-line because of the heavy ice build-up on lines in that area.

“When lines go together it can cause breaker operations to go off and cut some power,” said Studer. “It was really isolated in that Garvin area, and we found a couple of different problems around the Marshall area as well with some breakers that were frozen shut.”

Reports from areas served by Lyon-Lincoln Electric Co-op, which receives power transmissions services from East River, indicated there was about one inch of ice that had accumulated on East River’s high-voltage lines in a number of areas in southwest Minnesota. The lines in Garvin were bad enough to cause a breaker trip in East River’s Marshall substation, which shut off power down the East River transmission line from the Marshall substation to Garvin and places in-between, Studer said. East River crews re-routed power from a substation near Ivanhoe to provide power to the affected areas.

The ice build-up, combined with high winds, also caused flickering and smaller outages throughout the area, including at SMSU, which was without power for about seven minutes.

Residents from Lynd to Tracy reported periods of power outages. The city of Tyler, along with Ghent, Russell and Lake Benton, was without power between 7:45-7:52 p.m. Power in Ghent and Lynd went off again from 8:58-9:17 p.m. The city of Amiret was out for seven minutes before 8 p.m. and then suffered a longer outage from 8:58-11:23 p.m. Lake Benton was down again from 8:58-9:09.

East River Electric is headquartered in Madison, S.D., and has 24 member electric cooperatives, 14 power supply substations and 212 distribution substations, supplying power to 2,800 miles of transmission lines.

Things were also dicey in parts of Murray County on Monday night with some areas losing power for lengthy periods of time.

Jerry Mausbach, line superintendent for Nobles Co-op Electric, said the cause of the power outage was similar to what happened in neighboring counties where lines were slapping together because of strong winds.

“The slang for what caused it is ‘line gallop,'” Mausbach said. “It’s the same thing that happens when we have an ice storm and the lines start galloping, or, for lack of a better word, flopping around. We didn’t have the ice, so we’re suspecting some lines might have had some impacted snow sticking on the lines to generate that airplane wing effect. They can do it if the wind is in just the right direction.”

Mausbach said Xcel Energy re-routed power by switching out a section of line that was experiencing the worse gallop, and that power was back-fed to one of the substations.

A substation in Murray County was still down as of Tuesday morning, and crews were out inspecting lines to make sure the gallop in the lines had abated enough to go back on-line.