交联聚乙烯试样中空间电荷输运特性的数值模拟

The accumulation of space charge in the insulation of extruded cross-linked polyethylene (XLPE) high voltage DC cable will cause local field strength distortion and reduce the insulation performance of the material. The temperature gradient generated by the thermal effect of the conductor in the cable in the insulating layer will further affect the charge behavior. The modification of nanoparticles is an effective measure to suppress the space charge, whereas, how to realize the inhibition, especially for the carrier transport process at the micro level, needs to be deeply analyzed. The numerical simulation of space charge in the sample can explore the interaction and evolution process between various micro particles. Based on the bipolar charge transport model with limited carrier extraction, this paper studies the charge behavior under temperature gradient and the effects of deep traps and shallow traps on the carrier migration process. The results show that the low temperature side will accumulate heteropolar charges due to limited extraction, deep traps will limit carrier transport, and there is a bottleneck in the role of deep traps. With the increase of mobility, the charge distribution changes from homopolar to heteropolar. When the mobility is large enough, the heteropolar charge will not increase or even begin to decrease.