Two Large Autotransformers Due to Arrive in Maine

Central Maine Power Co. is getting ready to take delivery of two 286-ton electrical transformers (15’H x 13’ W x 38’ L) for the company’s new Maguire Road Substation in Kennebunk and Coopers Mills Road Substation in Windsor — both part of the Maine Power Reliability Program (MPRP).

The autotransformers were due to arrive in Maine by ship the week of May 6. Once offloaded from the ship, the units will be prepared for transport via rail and truck (16-axle tractor-trailer rig with a State Police escort) to their respective destinations. The total gross weight of the truck and transformer assembly is 426 tons (more than 852,000 pounds).

Central Maine Power’s MPRP is a $1.4 billion investment in Maine’s bulk power transmission system. The five-year project includes the construction of six new 345,000 V substations, upgrades to more than 40 existing substations, and the installation or rebuilding of nearly 440 mi of transmission line in 75 communities from Eliot to Orrington.


The autotransformers for the Maguire Road and Coopers Mills Road Substations are among the largest units in the Central Maine Power system. Transformers are used to raise or lower voltage on electrical systems. They will step down transmission line voltage from 345 kV to 115 kV to supply the electrical grid for communities across large areas of central and southern Maine.