Investigation on the Design of DC Cable Insulation

Abstract

In this paper, the appropriate expression on resistivity and electric field for the DC cable insulation is proposed based on the available experimental data. It is indicated that there is e index relationship between resistivity and temperature, and there is power exponent relationship between resistivity and electric field. The effect of conductor temperature, the temperature difference of insulation etc. on the electric field distributio of DC cable insulation is analysed. It is shown that the high conductor temperature and the large temperature difference in insulation make not only the insulation property decline but also the electric field distortion. There is no effect of resistivity coefficient on the distribution of electric field, but the low coefficient leads to the decrease of DC cable ampacity. Based on the electric field expression, the life expression and effect of space charge, the method on design of DC cable insulation is proposed.