American Transmission Co. projects

Project website for a Wisconsin-based company that owns and operates the high-voltage electric transmission system that powers communities in portions of the Upper Midwest.

ATC completes two grid projects in eastern Upper Peninsula

High-voltage direct-current device, rebuilt lines improve reliability, operations

DE PERE, Wis. – American Transmission Co. has improved the reliability of the electrical grid in the Upper Peninsula with the completion of two projects in the St. Ignace, Michigan, area.

A new high voltage, direct-current flow control device and associated substation also were placed into commercial operation in late summer. The innovative device allows operators to better manage the flow of power into and out of the Upper Peninsula, strengthening local-area electric reliability. The project was built by ABB, an international power and technology group. The facilities are located in Moran Township, just north of U.S. Highway 2 west of St. Ignace. The project also was completed slightly under budget at a cost of $125 million.

“The HVDC device helped us avoid two near-certain outages since it began operation,” said Paul Roehr, director of operations for ATC. Previously, the transmission facilities in the eastern U.P. were tied to Lower Michigan, and the western U.P. facilities to northern Wisconsin. The U.P. facilities were separated at a substation near Engadine because the system could not support the flow of power across the width of the peninsula. The HVDC device now provides the support to connect the two regions.

“An unplanned outage on transmission facilities in northern Wisconsin almost surely would have caused customers in the U.P. to lose service, but the HVDC device provided system support, maintaining reliability by allowing a continuous flow of power,” Roehr said. “In one of those instances, some customers in northern Wisconsin also would have been affected.”

Two 69,000-volt transmission lines that were built in the 1930s between St. Ignace and Rudyard also have been upgraded in a construction project that began in late 2012. The new lines are built to 138,000-volt standards, but continue to be operated at 69-kV. They operate more efficiently, reducing energy losses on the system and lowering operating and maintenance costs. They also provide more flexibility in routing power in the area. The project was completed slightly under budget at a cost of $43 million.