Effects of Tip Radius of Curvature on Electrical Tree Growth and Partial Discharge Characteristics of XLPE

Electrical tree is a common phenomenon in XLPE cable, there may be spike defects of different scales during cable operation. There are few reports on the influence of tip curvature radius on XLPE electrical tree. In this paper, the differences of electrical branch growth morphology and partial discharge characteristics under different tip curvature are studied. The experimental results show that a small radius of curvature of the tip has a high probability of developing into a branched electrical tree, and a large radius of curvature has a high probability of developing into a plexiform electrical tree. The discharge amount of the plexiform electrical tree is greater than that of the branched electrical tree. The positive and negative half cycle of the PRPD diagram of the bush electric tree is similar to the “wing shape”, the discharge shape of the positive half cycle of the branch tree is “△ shape”, and the negative half cycle shape is “wing shape”. The growth rate of the two trees shows the characteristics of “fast-slow-fast”. The growth rate of the branch tree is higher than that of the cluster tree, and the branch tree is more harmful in the actual cable.