Simulation of space charge transport in solid dielectric materials using transmission lines modeling method

Abstract

In this paper, a lumped RC circuit model, which is based on the Transmission Line Modeling (TLM) method, is used to describe the space charge production and displacement mechanisms in three different solid dielectric materials (LDPE, PTFE and FR4). Each dielectric material is considered as a transmission line with the capacitive and resistance elements. The obtained circuit equations are solved along with the continuity equations for the various charged species in the bulk of solid dielectric material. The electric potential and field, density of different charged species and their recombination rates, resistive and capacitive properties of the solid dielectric material are calculated. In addition, the effects of the variations in the applied voltage, dielectric permittivity and temperature on these physical parameters are examined. Besides, compared with LDPE and PTFE, the net charge density increment rate in FR4 is much higher. Moreover, the influences of temperature on the net charge density in LDPE are not significant. Furthermore, at the higher applied voltages, the current density is increased. Interestingly, the effects of temperature variations on the recombination rates, net charge and current density in LDPE are much lower. Hence, the suitability of LDPE as solid dielectric material is proved.

Keywords

• solid dielectric materials
• high voltage devices
• space charges
• tlm method