Impacts of different defects on electrical field distribution in cable joint

摘要

Defects in cable joints, induced in the process of manufacturing or assembling, can alter the distribution of the electrical field seriously. To investigate the impacts of different defects on electrical field distribution in cable joints, equivalent models of 110 kV cable joints with needle damage, impurity defect and scratch in insulation are established, respectively. The distribution of electrical potential and field strength in cable joints with dissimilar defects is obtained by finite element analysis (FEA). The results indicate that the needle damage, among the three different defects, generates most excessive electrical field strength distortion surrounding the defect, even exceeding the breakdown strength of air. The results show that these defects can easily result in partial discharge (PD), which leads them to pay more attention to the operation of cable joints.