Evaluation of MV-XLPE cables

An extensive investigation of the long term wet ageing performance of MV-XLPE power cables was started by Nordic (Norway, Sweden, Denmark and Finland) utilities and cable manufacturers in 1990. Representatives from the manufacturers and utilities were members of the project Steering Committee. The investigations were performed by the Norwegian Electric Power Research Institute (EFI). The work was divided into two parts, a three years research part and two years accelerated long term wet ageing test. In the research part, a total of 5 km cable core of old and new constructions were tested. 3.8 km of this cable core were aged under wet conditions in EFI's laboratories over a period of three years. The aim was to identify the effect of different ageing parameters in order to establish test procedures and evaluation criteria for accelerated long term testing of MV-XLPE power cables. Based on results from the research work, a two year accelerated long term test was proposed, and in the summer of 1993 the wet ageing of cables from 15 European cable manufacturers war started. In the autumn of 1995 these cables were tested to breakdown with an AC step test. 14 of the 15 cables met the requirement set by the Steering Committee.