American Transmission Company (ATC) on Aug. 20 said that it will begin the approximate 30-day process of removing two of six submarine electric transmission cables from the lakebed of the Straits of Mackinac starting on Aug. 24, as part of the company’s $105m Straits Cable Replacement Project, which will be complete by December 2021.
The project is designed to restore electric system reliability to the region following an April 2018 anchor strike that damaged the cables, the company said.
ATC noted that it has received permits from the U.S. Army Corps of Engineers and Michigan’s Department of Environment, Great Lakes, and Energy to conduct the work.
The company noted that its contractor, Durocher Marine, a division of Kokosing Industrial, Inc., will remove about six miles of de-energized cable in total across the waterway.
ATC also said that it is partnering with LS Cable Systems America, Inc., a subsidiary of LS Cable & System Ltd. of South Korea, to produce and install the replacement transmission cables.
Beginning in 2Q21, Durocher Marine will contract with LS Cable Systems America, Inc., to remove the remaining submarine cables and replace both circuits with two, three-phase 138-kV cables containing solid dielectric insulation, ATC said, adding that the project also involves necessary upgrades at the Point La Barbe substation in St. Ignace and the McGulpin Riser station in Mackinaw City.
As noted on the project’s webpage, Michigan’s Upper Peninsula (U.P.) and lower Michigan have been connected electrically for decades by two underwater, 138-kV transmission lines, comprised of the six cables. ATC’s lines were damaged in April 2018 when an anchor severed two of the cables and severely damaged a third, the site noted, adding that the three undamaged cables were reconfigured to form a single transmission line, allowing the company to restore an electrical connection between the U.P., and lower Michigan.