Central Maine Power Co. (CMP), a subsidiary of Iberdrola USA, recently deployed crews from Haverfield Aviation to make repairs on an energized 115-kV transmission line in a remote corridor through the western Maine mountains. Lineworkers suspended from helicopters replaced more than 30 old splices along the line in early July without taking it out of service.
“Using helicopters and aerial crews allowed us to perform preventive maintenance in a remote corridor where access is always a challenge,” said Joe Purington, director of System Operations for CMP. “Doing this work on an energized line allowed us to avoid any disruption to customers, and they’ll have more reliable service in the future.”
The 24-mi transmission line follows a corridor through a mountainous area between the towns of Moscow and Carrabasset Valley. Access to the corridor is difficult in many areas, especially in bad weather, so the company’s preventive maintenance could reduce the risk of long outages from equipment failure or storm damage. For the same reason birds can safely perch on live electrical lines, performing this work on energized lines from a helicopter is safe for crews because the helicopter and lines are at equal electrical potential and the helicopter is isolated from the ground.