Effects of temperature gradient on space charge accumulation at applied voltage reversal in LDPE film

Temperature gradient through the cable thickness occurs due to Joule heat arising from the electric current in the high voltage cable conductor, and affects the injection and migration of charge, leading to the insulation failure while a sudden power off or polarity reversal takes place due to the charge accumulation. In this article, based on the PEA (pulsed electroacoustic) method, the space charge accumulation and maximum transient electric field distortion during polarity reversal were studied under the different temperature gradient and a direct current stress of 50kV/mm. The experimental results show that the maximum steady-state electric field was measured near the low temperature electrode, but the maximum transient electric field could appear near the high temperature electrode.