Numerical Simulation of Surface Charge Accumulation on DC-GIS Insulating Spacer with Charge Transport Model

Surface charge accumulation on an insulating spacer in DC-GIS under high DC electric field is a problem because it decreases a breakdown voltage on the spacer. However, charge accumulation phenomena of an insulator are not well known. In this study, surface charge distribution at 40°C and at R.T. were measured and simulated. Simulation is performed with the charge transport model which had been developed to calculate electrical conduction in polyethylene. The model modified to calculate interfacial charge accumulation is applied to the experimental system consisting of the epoxy spacer and SF6gas. The measured tendency of the surface charge accumulation was simulated with the charge transport model on the assumption of changes in the trapping properties at the epoxy interface. The simulation results provide the description of the temperature dependence of the surface charge accumulation.