Minnesota Power (ALLETE)

Great Northern Transmission Line 500kV Overhead Project, MN

Wilson, in a joint-venture with Hooper Corporation, built a 224-mile 500kV transmission line from the Canada-U.S. border into Minnesota.

The line design was a guyed delta configuration with 1192.5 ACSR “Bunting” three-bundle conductor. Most structures were lattice steel single-leg guyed towers on helical pile foundations.

Hooper-Wilson’s execution plan focused on use of light-duty to heavy-lift helicopters, unique access and fly yards, winter weather construction, timber matting, and custom conductor installation equipment.

These solutions solved the challenges of a right-of-way inaccessible by standard equipment. The Hooper-Wilson team overcame soggy peat bogs in the spring and summer and layers of ice and snow in the winter.

Together, the Hooper-Wilson team, after careful coordination and effective communication with the project owner, completed a successful project on time.