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Project: T173700 #33/113

Infrequent failures of overhead transmission line (OHTL) facilities, particularly under extreme loading conditions, are inevitable if engineers are doing their jobs effectively as it’s impractical and unreasonable from the perspective of costs to design, construct and maintain facilities such that there is zero risk of failure. Therefore, failures will occur and when they do there is much to be learned.

However, all too often information that could prove invaluable to improve design, procurement, and construction and maintenance requirements is irretrievably lost as crews clear failed components and debris in order to facilitate line crew access, the restoration processes, and a safe work site. The situation is exacerbated by a lack of understanding among utility personnel regarding the value of collecting failure event information before a failure site is disturbed.

To assist in addressing this gap in knowledge and subject matter resources, CEATI TODEM contracted with the Project Team of EDM International, Inc. (EDM) and POWER Engineers, Inc. (POWER) to develop a state-of-the-art report on OHTL failures, including a failure investigation protocol. This report draws on a utility survey, a literature review, and the team’s failure investigation expertise to create resources and recommendations for utilities looking to develop a failure investigation protocol.


Transmission line, Failure investigation, Failure analysis, Failure event, Material, Protocol, Design, Load, Support structure, Tangent structure, Suspension structure, Dead-end structure, Triggering event, Victim event, Anomaly, Wire system, Support system