It can be said that one of the pillars of asset management for transmission lines and several otherasset categories is a clear understanding of when components cease to provide the required level offunctionality and need to be replaced. The art and science of asset management for transmissionlines has been in use for many years to varying degrees. Over the last 15 years or thereabout, assetmanagement has taken on an amplified and more rigorous application based on emerging needs thatgo along with aging assets. Many utilities have developed their own asset and componentreplacement criteria, as presented in this report, but it appears that the industry at large has not fullyaddressed this aspect of managing transmission line assets. This report outlines the sustainmentinvestment planning process, complications that an asset manager faces when managing the lifecycle of transmission lines and insight into utility practices. As well, templates and a format fordetailing component replacement criteria for some components that have been in use for many yearsare provided. These components include ACSR conductors, galvanized steel shield wires, woodpoles, timber arms, steel tower members, steel poles, porcelain insulators, glass insulators and ubolts.Steel grillage and concrete foundations are discussed from the context of end of life, howeversince they are buried and difficult to assess, follow-up work is needed to better address theidentification of conditions that would prompt replacement. Polymer insulator replacement is alsodiscussed, recognizing the already-completed quality work on the topic of condition rating thatutilities might be able to use for their purposes. As there are few guides available that detailreplacement criteria for transmission line components, there is much to be done to fill this gap.
Transmission line, transmission line components, component, replacement criteria, componentcondition, component life cycle, asset condition