Scottish Power Energy Networks says it needs to replace much of the ageing system with a new higher voltage line.
A document is being circulated to residents outlining the background to the project with a map of proposed pylons and sub-stations.
It comes ahead of a first round of public consultation on the plans.
SP Energy Networks said the Dumfries and Galloway Strategic Reinforcement Project aimed to modernise the network making it "more resilient for homes and businesses" as well as increasing capacity.
It said much of the existing 132,000 volt (132kV) system was coming towards the end of its operational life.
The project proposes a new high voltage overhead line of up to 400,000 volts (400kV) between Auchencrosh in South Ayrshire and Harker in Cumbria.
Initial consultation will seek views on a broad corridor of land that has been identified where potential routes for a new overhead line could be situated.
Broad siting areas have also been identified where the substations could be built.
SP Energy Networks said the proposed route - covering 109 miles - had been chosen to have the least impact on the environment and the local population.
The pylon route is earmarked to cover six zones from Auchencrosh to Newton Stewart,  then on to Glenlee before a three-way split to Kendoon,  Tongland and northern Dumfries where the line turns towards Carrutherstown, before heading north east to Ecclefechan then south into Cumbria.
SP Networks said 80 miles (130 kilometres) of old power lines would be removed as part of the project.
The plans will be subject to four rounds of consultation and revision over the next four years before being submitted to Scottish ministers for consent.
Consultation events will take place at the following venues:
A major project has been unveiled to modernise the overhead power line network stretching from Ayrshire across Dumfries and Galloway and into Cumbria.