The line runs through Dumfries and Galloway.
The Dumfries and Galloway Strategic Reinforcement project will replace the existing 132kV system, which is completing its operational life, with a new higher voltage overhead line of up to 400kV.
The new 109 miles high voltage line will run between Auchencrosh in South Ayrshire and Harker in Cumbria.
Four new substations will also be developed as part of the proposal in the regions. According to SP Energy Networks, the route, which will replace 130km of old power lines, will reduce impact on the environment.
As part of its effort, the company intends to hold a series of public consultations next month to solicit views on a potential route for the new overhead line.
The proposal is subject to consultation and revision, which will be conducted in four rounds over the next four years. The company will then submit the plan to Scottish ministers for approval.
