Three undamaged cables combined to form a powerline across Straits of Mackinac
PEWAUKEE, Wis. – American Transmission Co. has restored the electrical connection between the Upper Peninsula and lower Michigan. Two powerlines made up of six submarine cables in the Straits of Mackinac tripped offline Sunday, April 1. Three cables are needed to make one circuit, or powerline. Two of the cables – one in each circuit – were damaged, possibly by vessel activity, and were subsequently decommissioned after they were found to be releasing dielectric insulating fluid. Subsea inspections revealed that at least three of the remaining cables were undamaged and operable; ATC reconfigured and tested those cables to create a circuit across the Straits. The new circuit went into operation on Tuesday, May 1.
“This connection is essential for reliability for the eastern U.P. and the northern portion of lower Michigan,” said Mark Davis, chief operating officer for ATC. “We were able to maintain reliability by implementing conservative operating procedures during the month the connection was lost, but re-establishing this powerline will give us greater flexibility and an added measure of reliability to help us keep the lights on.”
The damaged cables have been soldered, capped, sealed and returned to the bottom of the Straits. ATC is making plans to permit and construct two new circuits in the Straits using a solid dielectric insulator, and to eventually decommission the six fluid-filled insulating cables. No firm timeline or cost has been established.
“We thank all the participants in the Unified Command, led by the U.S. Coast Guard, for the safe and efficient response to this incident,” Davis said. “The coordinated response helped minimize impacts to the environment and local community.”
Note to editors:
For additional information, please visit http://www.atcllc.com/straitscables/
American Transmission Co. has created a website for information about the damage to two electric power lines under the Straits of Mackinac last week. The website provides an overview of the situation, ATC’s infrastructure and response. Please refer to the site for the latest information from ATC. For information about the recovery effort, please contact the U.S. Coast Guard’s Joint Information Center in Mackinaw City via email at PointLeBarbeResponseJIC@gmail.com or (906) 748-0737.
PEWAUKEE, Wis. — American Transmission Co. today took the unprecedented step to shut down two submarine cables in the Straits of Mackinac that electrically connect the Upper Peninsula to lower Michigan as the result of yet-undetermined damage.
The cables tripped offline about 30 seconds apart Sunday evening, April 1. A patrol of the overhead elements of the system between Point Lebarbe in St. Ignace and the McGulpin Riser Station in Mackinac City showed no damage. The submarine cables, which contain a mineral-based fluid for insulation, were monitored overnight and subsequently determined to be leaking. Pressure on the system was reduced to minimize the fluid leak as maintenance, environmental and operations personnel worked to locate the compromised section of the cables on Monday, April 2. Investigations included aerial patrols over the Straits, cable testing and system reconfiguration options.
Extreme weather conditions, including icing in the channel and on shore, hindered the damage investigation and contributed to ATC’s decision to shut down the cables this morning, April 3. As a result, the two cables cannot be repaired and have been rendered permanently inoperable. ATC will be determining the condition of other cables in the Straits.
“It was an extraordinary set of circumstances, but ultimately, the decision to shut down the cables had to be made,” said Mark Davis, ATC chief operating officer. “We will continue to investigate the cause of the incident, determine any necessary remediation efforts and continue communicating with the appropriate regulatory agencies.”
ATC has notified the National Oceanic and Atmospheric Administration, Environmental Protection Agency, U.S. Coast Guard, U.S. Fish & Wildlife Service, Michigan Department of Environmental Quality, Michigan Department of Natural Resources, and the Michigan Public Service Commission of its decision to shut down the electrical cables.
ATC owns and operates most of the electric transmission grid in the Upper Peninsula. The system continues to operate normally at this time. ATC is coordinating with the Midcontinent Independent System Operator and Midwest Reliability Organization to determine short-term and long-term solutions.
Project will connect expanded West Riverside Energy Center to electric grid
Madison, Wis. – American Transmission Co. on Jan. 12 received approval from the Public Service Commission of Wisconsin to construct an approximately 4.2 mile, 345,000-volt Riverside Transmission Line Project. The project will consist of a double-circuit transmission line from a planned new substation near the Alliant Energy West Riverside Energy Center to an existing 345-kV transmission line in the Town of Beloit.
The line is needed to connect the expanded West Riverside Energy Center to the electric transmission grid. The West Riverside Energy Center will include a natural gas-fueled generating station with an integrated solar installation.
“The ordered route is made up of segments from the two routes that ATC submitted to the PSC,” said ATC Project Manager Mark Sanzenbacher. “The anticipated project cost is approximately $42 million.”
The planned in-service date of the line is 2019. The PSC order and other documents associated with the proposed project are available at www.psc.wi.gov. The docket number for this project is 137-CE-186.
Community Planting Program recognizes communities for vegetation projects that help keep transmission lines safe and reliable
PEWAUKEE, Wis. – American Transmission Co. has awarded $56,000 collectively to 27 communities across its service area for the purpose of planting trees and other vegetation through its Community Planting Program. Vegetation funded through this program requires that communities plant trees outside of high-voltage transmission line rights-of-way, helping to keep the electric transmission lines safe and reliable.
“Now in its fifth year, the Community Planting Program has awarded nearly $300,000 to more than 175 communities for planting projects,” said Mark Davis, executive vice president and chief operating officer. “This is an initiative that we continue to be proud of because ATC is committed to helping sustain the environment that we all share. These communities also demonstrate their commitment to helping us keep the lights on by planting tall-growing vegetation a safe distance from transmission lines.”
In addition, recipients of the Community Planting Program commit to comply with ATC’s maintenance standards for all current and future planting plans and urban forestry activities near high-voltage electric transmission lines. The following Wisconsin communities received amounts ranging from $500 to $5,000 for planting projects on public property. Villages of Friendship and Somers received funding to support pollinator planting projects, as part of ATC’s pollinator initiative:
|Bellevue||Fond du Lac||Manitowoc||Outagamie County||Stevens Point|
|Beloit||Friendship||Menasha||Ozaukee County||West Allis|
|Biron||Gays Mills||Ho-Chunk Nation||Peshtigo|
|Brooklyn||Grafton||Little Chute||Sheboygan Falls|
The Community Planting Program is part of ATC’s Grow Smart program, which advocates for and provides suggestions of low-growing, compatible vegetation that can be planted in transmission line rights-of-way. ATC will accept applications again for the Community Planting Program from June 1 through Sept. 30, 2018.