Calculation of electric field and temperature field distribution in MVDC polymeric power cable

Calculation of electric field in direct current (DC) polymeric power cable should consider the change of electric field resulting from conductivity and space charge. The electric field in a solid dielectric material under DC conditions is determined by conductivity which is a function of electric field and temperature field. Additionally, the space charge accumulated in cable insulation also influences the distribution of the electric field. In this paper, it shows the necessity of considering both conductivity and space charge in terms of current field and electrostatic field. A medium-voltage direct current (MVDC) crossed polyethylene (XLPE) cable of 30 kV has been chosen as the simulation object. In the simulation, the expression of conductivity is obtained from empirical formula and the space charge distribution across cable insulation is measured by pulsed electro-acoustic (PEA) system. COMSOL multi-physics software package is taken as the simulation tool for calculating the electric field and temperature field distribution.