AN ASSESSMENT OF FIELD-AGED 15KV AND 35KV ETHYLENE-PROPYLENE RUBBER INSULATED CABLES

Data are provided from laboratory evaluations performed on ten 15kV an d five 35kV ethylene-propylene copolymer rubber (EPR) feeder cables, m ade by one manufacturer and ranging in service age from 2 to 22 years. The evaluations consisted of visual examination of cable components, including the presence of water trees in the insulation and physical a nd electrical tests to establish changes which may have occurred in se rvice. The data are used to establish an in-service rate of degradatio n for cables, up to 13 years in service, made with one type of EPR for mulation. Based on an extrapolation of the breakdown voltage test resu lts, it is expected that this type of cable will have a service life i n excess of 30 years.