Research on Simulation Algorithms for Two Dimensional Models of Space Charge Dynamics in High Voltage DC Cable Insulation

In order to simulate the space charge behavior in high voltage DC cable insulation, this paper proposed a simulation algorithm for space charge transport based on two dimensional unstructured mesh, which combined with bipolar charge transport model. The algorithm is based on iteratively solving the Poisson equation and charge conservation equation. The finite element method (FEM) is employed to solve the Poisson equation and the finite volume method (FVM) is employed discretizing the charge conservation equation on a cell-centered tessellation. In order to ensure the charge density in a reasonable range and in second-order accuracy, a linear reconstruction with limiter for charge density was adopted in the insulation domain. The comparison results of space charge simulation of 4mm-thick cable insulation in two dimension and measurement with a full-size space charge system based on pulsed electro-acoustic (PEA) method validate the accuracy and effectiveness of the proposed algorithm. The space charge simulation in two dimension shows that when the cable length is far outweigh that radius, the space charge uniformly distributed along the axial direction apart from both ends. Thus the space charge simulation could modeled in one dimension along radius in such condition. However, the space charge distribution differs obviously along the axial direction at both ends, which suggests the necessity to call for a two dimensional model for simulation of the charge behavior in cable insulation to improve the accuracy. © 2019 Chin. Soc. for Elec. Eng.