The effects of conductor loading and ingress of moisture into the cable insulation on the partial discharge and loss tangent values of 6.6-kV cross-linked polyethylene (XLPE) power cable samples under different voltage stresses have been investigated. The results obtained indicate that partial discharge values of XLPE cable samples, which have undergone load cycling and moisture absorption, are higher than those of unaged cables, and the magnitude depends on the voltage stress applied. The partial discharge values measured are higher than the allowed limit at higher voltage stress for the cables exposed to moisture absorption. The conductivity of water used for moisture absorption has considerable influence on the partial discharge magnitude. Increase in loss tangent values after aging tests has also been observed. The power frequency breakdown voltage of XLPE cable after moisture absorption is lower than the value obtained after the load cycling test.
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