It's hoped a planning application for EirGrid's North Connacht 110 kV project will be submitted by the end of the month.
The underground cable will run to the Tonroe Substation in Ballaghaderreen from the Moy Substation in Ballina, which is a total of 60 kilometres.
The new powerline is due to enhance the electricity network in the area and will connect new renewable generation onto the national grid.
A planning application will now be made to An Bord Pleanála and it's hoped work will begin in 2023 with a completion date in 2026.