Failure prediction of underground distribution feeder cables

This paper presents a methodology to determine an age-related reliability index that can be used to compare the relative likelihood of in-service failures among underground distribution feeders. It was developed for the Con Edison 27 kV and 13.8 kV distribution systems but is sufficiently generic to apply to any group of underground distribution feeders. Each feeder is represented by a combined reliability model of its individual components, including the following: cable sections-paper and solid dielectric insulated cables; cable joints-paper-to-paper, paper-to-solid dielectric and solid dielectric-to-solid dielectric insulated cable joints; and network transformers. The parameters of each component model are determined based upon historical failure data according to age. The confidence level associated with the prediction is also determined, and a brief description of the computer program developed and its application to Con Edison´s Yorkville 13.8 kV primary distribution network are provided