AUGUSTA, Maine - Central Maine Power Co. recently completed its summer inspections of its transmission lines. The annual inspection flights are an important part of the utility's efforts to ensure safe, reliable delivery of power to homes and businesses throughout its service area.
Line inspectors on board a helicopter flying over the energy company's transmission system use infrared equipment to look for "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," said Doug Herling, Vice President for Electric Operations. "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 (about the same distance between Portland, Maine and Portland, Oregon), and performs the infrared inspections on a four-year cycle, with about one quarter of the system checked annually. The utility also does aerial patrols following severe storms or when its Energy Control Center detects an abnormality such as a momentary outage from a lightning strike or a change in voltage.
Each spring and fall, CMP also does a visual inspection of all of its transmission rights-of-way from the air. These flights help spot potential problems with equipment, as well as signs of unauthorized use.
"Unauthorized uses in our corridors can pose a risk to our energy grid or the environment," said Herling. "We want to be a good neighbor by preventing abuses such as off-road vehicle use or disposal of trash or brush."