Temperature Gradient Effect on the Conductivity of an XLPE Insulated Polymeric Power Cable

Distribution of electric field across the insulation of high voltage direct current (HVDC) is affected by the conductivity of the material, which is a function of both temperature and electric field. To understand the effect of temperature on the conductivity of the insulation across a dc power cable under load condition, an investigation is conducted on the electrical conductivity of the cross-linked polyethylene (XLPE) peelings from a undegassed 11 kV ac polymeric insulated power cable. The results highlight the complexity of electric conduction in the XLPE peel where it strongly relies on both the application of high electric field and temperature, suggesting that the conduction is space charge limited and injection controlled. Furthermore, thermal activation energy of the material is obtained based on the measured material properties where the dependences effect on the dc cable is being considered.