Breakdown mechanism studies in crosslinked polyethylene cable

This research explores the basic hypothesis that microporosity may play a significant role in the mechanism of breakdown of XLPE cable. The potential improvement achieved by impregnating the cable core with a neutral liquid is evaluated, in relation to ac voltage life and impulse strength. The effect at higher frequency voltage is also considered. Absence of measurable discharge on cable samples at very high stress raises some question regarding the role of partial discharges in relation to the mechanism of dielectric fatigue and breakdown. The possibilities of alternative electronic mechanisms are discussed. Studies are continuing under this EPRI/DOI research contract.