直流预压对针板电极下XLPE中空间电荷及电树枝的影响

空间电荷是影响高压直流电缆绝缘电树枝特性的主要原因之一。基于双极性载流子输运模型，对±20 kV、±22.5 kV和±25 kV直流预压下3 600 s内二维针板电极模型空间电荷分布进行仿真分析，并对比分析空间电荷分布与直流接地电树枝引发特性。结果表明：空间电荷浓度及注入深度随预压幅值及时间的增加而增大；直流接地电树枝引发长度随预压时间及幅值的增加而增加。空间电荷注入深度与电树枝引发长度两者之间高度相似。接地电树枝引发特性存在差异的主要原因是针尖附近空间电荷的分布特性。

Effect of DC Pre-stress on Space Charge and Electrical Tree in XLPE with Needle-Plate Electrodes

Space charge is one of the main factors that affect the electrical tree characteristics of HVDC cable insulation.Based on the bipolar charge transport model,this paper simulates the space charge distribution characteristics of the two-dimensional needle plate electrode model under±20 kV、±22.5 kV and±25 kV DC pre-stress with a duration of 3600s,and makes a comparative analysis between the space charge distribution characteristics and the DC grounded electrical tree initiation characteristics.The results show that the space charge density and injection depth increase with the increase of the pre-stress and time,and the initiation length of DC grounded electrical tree increases with the increase of pre-stress duration and amplitude.There is a high similarity between space charge distribution characteristics and electrical tree initiation characteristics.The space charge distribution near the needle tip is the main reason for the difference in the initiation characteristics of the grounded electrical tree.