Effects of metal impurities in insulation of distribution cables

Effect of metal impurities in insulation layer of distribution cables was investigated. The test samples of XLPE cables were fabricated with added metal impurities of Al,Cu,Fe, and electrical conductivity was measured in the voltage range of 0-10 kV. We observed the stimulated hysteresis curve, which becomes the relationship between forward and reverse charging currents. At the voltage range of 0.5/spl sim/10 kV, the charging current between the samples with and without carbon black electrodes became larger at higher voltage levels. In addition, some effects of the curves of charging current due to impurities are discussed.