The temperature sensitivity of conductance in XLPE under DC field

In this paper, the influence of temperature on the temperature sensitivity and conductivity mechanism of XLPE was discussed by detecting the conductivity characteristics of XLPE in the electric field range of 1-100kV/mm at a temperature of 30°C -70°C, and the temperature sensitivity of XLPE was analyzed. The results show that the conductance current increases with the increase of temperature, and the threshold electric field E 1 of charge injection decreases with the increase of temperature, which indicates that high temperature promotes charge injection, and the traps on the dielectric surface are easily filled with charge at high temperature. The threshold electric field E2 at high temperature was larger than E2 at 30°C, which indicates that high temperature promotes volatilization and decomposition of cross-linked byproducts and increases the trap density inside the sample. The conductance mechanism of XLPE was dominated by Schottky injection under about 10-100kV/mm, and electron jump conductance was dominant under 65-100kV/mm at 30°C. At high temperature, the conductivity of XLPE fluctuated greatly with the change of electric field. In the range of 1-100kV/mm, the temperature self-sensitivity coefficient α γ of XLPE were less than 20. In the single electric field of 20kV/mm stipulated by GB/T 31489.1-2015, the corresponding self-sensitivity coefficient of XLPE was 8.6. It was significantly better than the standard. This indicates that the XLPE insulation sample has low temperature sensitivity.