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.

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Walworth County to benefit from voltage boost to electric transmission lines

First 10 miles of 30-mile, multi-year, multi-phase system upgrade now operating at 138,000 volts

PEWAUKEE, Wis. – After more than five years of planning and construction, American Transmission Co. last week completed conversion of 10 miles of transmission lines in Walworth County to 138,000 volts. The voltage conversion is the first phase in ATC’s 30-mile conversion project in Rock and Walworth counties that will strengthen the electric system that serves the growing area.

The eastern segments of the project, from the Elkhorn Substation located in the City of Elkhorn to the Bristol Substation and extending to the Southwest Delavan Substation located outside of Delavan, are now energized and operating at 138,000 volts. The remaining 22 miles of western segments of this multi-year, multi-phase system upgrade will continue to operate at 69,000 volts until ATC completes construction and upgrades this summer.

“This is a key milestone in the project and immediately benefits residents and business owners in Walworth County,” said Mary Carpenter, local relations representative. “We are eager to complete the remaining work on the western segments and complete the entire conversion this summer.”

According to Carpenter, the remaining effort includes work on several substations in Rock County, modifications to some existing lines, and the replacement of an existing line through the City of Delavan between the Bristol and Delavan substations. “Crews will begin the work in Delavan next week and will wrap up in June,” she said.

The final phase of the project, which will begin this summer, includes removing several miles of existing 69,000-volt lines that will be retired once the conversion is complete. These include a line north of the City of Delavan and a line between the Bristol Substation and Lake Geneva.

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ATC is a Wisconsin-based company that moves energy along the regional electric grid in parts of Wisconsin, Michigan, Minnesota and Illinois, serving more than 5 million electric consumers. We are experts at what we do: planning, maintaining, operating and protecting the grid. As the electric industry moves toward renewable generation sources, we are transforming our system to continue delivering energy reliably and safely. We proudly support STEM education programs that empower youth with the skills needed to succeed in tomorrow’s energy workforce. For more information, visit and follow us on LinkedIn and X (Twitter).