Abstract:
The dynamic charge characteristics of XLPE under different thermal aging times are studied using DCIC-Q(t) technique. The curves of dynamic charge under different applied voltage is obtained, and the concept of charge ratio
k is put forward to judge the injection and accumulation of space charge. XLPE capacitance is obtained by fitting the linear relation between instantaneous charge
Q0 and voltage, and the variation rule between dielectric constant and thermal aging is further calculated and analyzed. The relationship between relaxation time and dielectric constant and conductivity is determined, and the variation curve of the conductance under different electric fields is obtained. The change of dynamic charge ratio, dielectric constant and conductivity of XLPE samples are analyzed, and it is found that with the thermal aging process, the three unchange at first and then increase quickly, indicating that the thermal aging of a short time has a little effect on the electrical performance of XLPE insulation, but the increase of aging time would degrade it. The XLPE lamellar experiment provides a theoretical basis for the whole cable aging evaluation model.