A model for bipolar charge transport, trapping and recombination in degassed crosslinked polyethene

Abstract

Measurements of the space charge density across the width of a plane parallel sample of degassed crosslinked polyethene (XLPE) have been made recently. Repeated at intervals throughout a period of applied high voltage, these measurements provide data on the dynamics of charge injection and space charge development in the sample under the influence of a stepped high DC voltage. In order to analyse these data, a simple model for bipolar charge injection, subsequent transport and trapping has been developed. This model is reported in this paper, and numerical simulations for charge density generated, as a function of position, time and field, are compared to the experimentally obtained profiles.