Charge Transport Simulation in XLPE Cable Insulation Based on Two-dimensional Unstructured Mesh

In a high voltage direct current (HVDC) transmission system, the equipments like cable accessory and bush are quite important. However, the charge behavior in the insulation of these equipments could not be simplified by one-dimensional charge transport model, for the asymmetry of the insulation structure or specific boundary conditions. This paper proposed a simulation method of the charge transport based on two-dimensional unstructured mesh. The charge transport equations refer to the equations of bipolar charge transport model. The finite element method (FEM) is adopted to solve the Poisson equation. The finite volume method (FVM) with a higher-order upwind scheme with limiter is adopted to discretize the charge conservation equation on a cell-centered tessellation. The simulation object of this paper is cable, and it is a new attempt to simulate space charge dynamics of cable insulation in two-dimensional. Although the charge behavior in cable insulation is regarded as one-dimensional in most simulation researches, the charge distribution in cable insulation could be directly measured by experiments. Thus, the accuracy of the simulation method in this paper could be verified by comparing the simulation results from one-dimensional view with the experiment results. With appropriate parameters, the simulation results are consistent with the results of experiments conducted in this study. The simulation method could further be applied to charge behavior simulation in practical insulation structure which call for a two-dimensional model, and has value in design of insulation structure.