Condition of T&D Assets

Powertech is coordinating an asset management program for overhead transmission components that utilizes a sampling protocol.

Unlike the costly assets in substations and power generation plants, where detailed and blanket condition assessments can be easily cost-justified, many T&D overhead components—such as insulators, cross-arms and through-bolts—are less expensive but massive in quantity and sparsely located. Thus, detailed on-site inspections would be labor-intensive, and inspections carried out from helicopters and from the ground have limitations.

To address these issues for BC Hydro, Powertech is utilizing a sampling protocol for asset management of overhead transmission components. As a cost-saving measure, Powertech works with utility field crews to take samples and collect asset data during routine utility line maintenance. This "sampling by opportunity" involves only an incremental additional cost and allows efficient data collection. Powertech uses the data compiled through sampling to determine correlations between condition, remaining strength, age, and geographic locations.

The program has also been extended to testing in-service transmission wood poles and cross-arms to determine remaining bending strength of the poles to evaluate whether the current replacement scope is adequate.