The region suffers from long interconnection queues, with as many 150 projects waiting to be connected in Minnesota alone.
The Badger Coulee Transmission Line would run from the town of Vienna near Madison, via Middleton, to the La Crosse area.
ATC said it has studied the proposed line for about two years, and would begin public consultation and detailed route identification this autumn.
It plans to submit an application to the state Public Service Commission in 2013, with aims to start construction in 2015 and bring the line into service by 2018.
The line would allow Wisconsin to import renewable energy while improving electric system reliability and saving customers money, ATC said.
Wisconsin ranks 18th in the country for its wind capacity, at 449MW, and 16th for potential with 300,136 GWh/year.
Neighbouring Minnesota ranks seventh for capacity with 1,812MW. Three major Minnesotan transmission projects are set to win approval this summer, include one that will cross the Mississippi River into Wisconsin.