Multiple dielectric relaxation mechanisms in XLPE cable insulation

The authors report an analysis of the current and complex capacitance parameters measured by time-domain spectroscopy on unaged XLPE (cross-linked polyethylene) cable samples. The frequency and temperature dependence of the complex capacitance showed the existence of an overlapping multiple relaxation mechanism. Although the study was done at very low electric field and with a very low value of total relaxing charge, an anomalous increase in absorption current was observed, resulting in the appearance of a peak in the real capacitance. The results obtained are generally interpretable in terms of the theory of interacting relaxing species as proposed by A.K. Jonscher (1986)