Electrical aging of XLPE power distribution cables in humid environment

The dielectric spectroscopy of the unaged and AC aged (6 kV/mm, 50 Hz, 6000 hours) XLPE cables (15 kV rating) show three relaxation processes in the frequency range of 10/sup -5/ Hz to 10/sup 5/ Hz. The behaviour of relaxation at the low frequency 10/sup -5/ Hz to 10/sup -4/ Hz changes significantly with the progressive aging of the cable and the nature of the thermally stimulated discharge current (TSDC) data are in qualitative agreement with that of the low frequency dispersion. The three relaxation processes are represented by a parallel combination of three R-C circuits. >