Location: Avon, Massachusetts
Owner: National Grid
Client: National Grid
Engineer: National Grid/Conceo
The new substation includes a 115kV circuit switcher, a 115/13.8kV 24/32/40 mega volt amperes load tap changing transformer, and a 13.8kV metal-clad switchgear with four feeder positions. It also includes a 13.8kV, 7.2 MVAR two stage metal enclosed capacitor bank and getaway ducts. A manhole system for four new 13.8kV feeders to address feeders and transformer overload conditions identified in the Brockton area. Harrison Boulevard Substation powers the city of Avon. This ten-month project is scheduled to finish in December 2015.
The design called for the installation of six, 330 feet deep ground wells to be filled with bentonite. Creating these wells without the walls collapsing was a major obstacle.
State Electric rented a ground pump to inject the bentonite into the wells. A standard 2 inch PVC sprinkler pipe was used and pulled up as the well was filled.