EXPERIMENTAL-OBSERVATION OF CHARGE TRANSPORT AND INJECTION IN XLPE AT POLARITY REVERSAL

This paper presents experimental results of space-charge distribution in cross-linked polyethylene (XLPE) by a pulsed electroacoustic method. The influence of polarity reversal on space-charge distribution in degassed XLPE and as-received XLPE is studied to understand the transport and injection of charges under DC voltage. Homocharge distribution is dominant in degassed XLPE whereas heterocharge distribution is dominant in as-received XLPE. After the applied voltage is reversed, for degassed XLPE, previously injected homocharges are neutralized by newly injected ones with opposite polarity; while for as-received XLPE, previously accumulated heterocharges are replaced by newly accumulated ones with opposite polarity. A new data display method of a three-dimensional colour plot is proposed to display all measurement data on one plot by which the time dependence of space-charge distribution can be understood easily and conveniently.