Estimation of life expectancy of wood poles in electrical distribution networks

Abstract

Wood poles have been commonly used to support electrical lines throughout Canada. The electrical networks in Ontario alone use over 2 million wood poles to support distribution lines. The aging and degradation of wood pole infrastructure built in 1950s and 1960s have potential to increase the risk of pole failure resulting in power outage and costly unplanned maintenance work. Therefore, the development of a scientific and cost-effective asset management philosophy has become increasingly important to power utilities. The paper presents a probabilistic approach to minimize the life-cycle cost of inspection and refurbishment of wood poles in a large distribution network. A key input of probabilistic methodology is the life-time distribution function of wood pole, though its estimation is often hampered by the lack of data. The paper presents a comprehensive statistical analysis and interpretation of actual wood pole inspection and surveillance data collected by power utilities. The statistical analysis provides estimates of life expectancy and the survival curve of a typical distribution wood pole in-service in the Canadian climate. The optimization of refurbishment policy presented in the paper is generic and equally applicable to the asset management of other civil infrastructure systems.