Tower of power
We often see rain and high winds in our service area. First thought for many of us? Concern that electricity distribution power lines might come down.
Downed distribution lines mean outages, and we’re all used to seeing lineworkers, on the ground, and in bucket trucks, repairing broken poles and wires.
But what would happen if a high-voltage transmission line came down – and not just a transmission line, but a high-voltage direct current (HVDC) line. We currently only have one HVDC line here at National Grid. This particular line imports 2,000 megawatts of inexpensive hydro-power from Canada approximately 1,000 miles from Northern Quebec near James Bay to Central Mass.
National Grid is the majority owner of the line and operates and maintains it on behalf of roughly 40 other companies that are co-owners.
While very rare, unfortunately, emergencies caused by natural disasters, extreme weather or vandalism can occur that could affect the reliability of this and other transmission lines.
Our due diligence and ongoing annual inspections have helped us avoid such emergencies, but we continuously prepare for an event where a line does come down or fails.
Recently, our New England Transmission Line Services (TLS) and Transmission Engineering (TE) teams trained with Lindsey Manufacturing Company, using its Emergency Restoration System (ERS).
The ERS is designed to restore transmission lines as safely and quickly as possible. The system consists of lightweight, welded aluminum modular structures (think towers), insulators, line hardware, anchoring systems, and all necessary tools for building temporary structures.
Simulating a worst case failure of the HVDC line, TLS and TE workers spent a full day erecting and dismantling temporary towers. They focused on the Chainette structure, a 400kV Lindsey ERS that would support the HVDC line during re-construction of the permanent tower.
Future training includes exercises where workers will use alternate construction methods based on terrain and geography to aid in erecting a tower.
Nick Gibson, TLS manager, says the training is simply part of the job: “It’s not a question of whether or not we’ll ever need to use Lindsey ERS. It’s about always being prepared to continue electricity service for our customers and communities, safely and timely.”
See below for pictures of the TE & TLS departments constructing the Lindsey Towers.