New Model for Acetophenone Ions in XLPE Insulation –Space Charge and Electric Field Characteristics Using Bipolar Charge Transport Theory

Bipolar charge transport (BCT) models have been used for the past few decades to simulate and analyze charge transport and its associated phenomena in polymeric insulation materials. Whilst in this method primarily, electronic charge carriers are used, recent studies show that there has been a high interest in the addition of ionic charge carriers and their physical processes in the model. Among the byproducts in the crosslinked XLPE, acetophenone is speculated to have deep electron traps and therefore can contribute to the electrical conduction processes in XLPE insulation, leading to charge and field dynamics in XLPE insulation. In this paper, a new model is attempted considering acetophenone for modelling the ions originating from acetophenone molecules, which demonstrates the charge and field dynamics in the insulation. Using the BCT model, combining with the electronic species, the impact of the presence of the ions is discussed. The ionic charge carrier and the neutral molecule are modelled based on Marcus theory. The results reported in this paper draw attention to the charge and field distribution for different ionic concentrations, the effect of thermal gradient and mobilities of the ions. A comparison between the experimental conductivity values from various literature and the proposed model has been done.