FAILURE PREDICTION OF UNDERGROUND DISTRIBUTION FEEDER CABLES

This paper presents a methodology to determine an age-related reliabil ity index that can be used to compare the relative likelihood of in-se rvice failures among underground distribution feeders. It was develope d for the Con Edison 27 kV and 13.8 kV distribution systems but is suf ficiently generic to apply to any group of underground distribution fe eders. Each feeder is represented by a combined reliability model of i ts individual components, including the following: Cable Sections: Pap er and solid dielectric insulated cables Cable Joints: Paper-to-paper, paper-to-solid dielectric and solid dielectric-to-solid dielectric in sulated cable joints Network Transformers The parameters of each compo nent model are determined based upon historical failure data according to age. The confidence level associated with the prediction is also d etermined, and a brief description of the computer program developed a nd its application to Con Edison's Yorkville 13.8 kV primary distribut ion network are provided.