CMP begins semi-annual flyby to inspect lines

AUGUSTA, Maine -- Central Maine Power has begun its spring inspections of its transmission lines by helicopter. The flights are an important part of the utility's annual inspection program to ensure safe, reliable delivery of power to homes and businesses throughout its service area.

Each spring and fall, CMP does a visual inspection of all of its transmission rights-of-way from the air. These flights help to spot potential problems with equipment, as well as signs of unauthorized use.

"When people encroach on our rights-of-ways with heavy equipment during logging and other operations, it poses a threat to both system reliability and public safety," says CMP spokesperson Gail Rice. "We also have had problems with people using our rights-of-way to dispose of old appliances, building materials, and cars, and even for ATV 'mud runs.' This unauthorized use is bad for the environment, and unfair to people who live nearby who should be able to enjoy some peace and quiet around their homes."

In addition to the spring and fall visual inspections, CMP also flies over its entire transmission system in the summer using a helicopter equipped with infrared thermal imaging equipment to detect "hot spots" that might need attention.

"Our lines are exposed to the weather all the time, and extreme temperatures and precipitation can take their toll on switches, clamps, insulators, and other equipment," says Rice. "These devices often heat up if there's been minor damage or wear, so inspecting the lines with infrared equipment lets us find and fix problems before they cause a power outage."

CMP owns nearly 2,500 miles of transmission line. Along with completing the semi-annual visual patrols and the yearly infrared inspections, the utility does aerial checks when its Dispatch Center detects an abnormality such as a momentary outage from a lightning strike or a change in voltage.