To keep the transmission system safe and reliable, we perform routine general maintenance. Some examples of this work would be replacing cross-arms, insulators, and poles, as well as work within our substations. As part of our Avian Protection Plan, we also install bird diverters on our transmission lines to reduce bird collisions.
Types of maintenance work
Ground patrols
Ground patrols are a visual inspection of each structure, as well as the conductor and cables between them and the vegetation along the line. One of the main concerns of these patrols is vegetation growth. Ground patrols must be completed between the time of the fall air patrol of each year and the start of the growing season (typically June 1) in the next.
Air patrols
A helicopter is used to inspect the entire transmission power line system to identify deficiencies. Typically, the patrols are conducted in early fall when leaves are still on the trees to allow assessments of the proximity of conductor and vegetation.
Insulator washing
A helicopter is used to wash contaminants, such as dirt and road salt, from insulators on energized transmission lines. When a transmission line is located too close to residences, ground crews will complete the washing. Distilled water will be used for the washing so there are no chemicals or cleaning agents.
This maintenance will not require the transmission lines to be taken out of service and residents should not notice any impact on their power. Where activities are required to take place on private property, we will contact you in advance to discuss the specific dates and times we will require access to your property.
Vegetation management
Throughout the life cycle of a right-of-way, different methods are used to control vegetation over the long term, in a cost efficient, effective and environmentally responsible manner. Methods can include manual tree control, brush mowing, tree trimming and herbicide application.
Learn more about our vegetation management plan.
Pole inspections
This inspection involves an internal and external evaluation of all wood pole structures. Typically pole inspections are done spring to fall when the ground has thawed out. Structures in wetlands are inspectable in the winter after freeze up.