针尖曲率半径对XLPE电树枝生长及局部放电特性的影响

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

电树枝在XLPE电缆中是一种常见现象,在电缆运行过程中可能会存在不同尺寸的尖刺缺陷。本文在不同针尖曲率半径下,研究了电树枝生长形貌和局部放电特性的关系。结果表明:针尖曲率半径小的试样在起树电压下大概率最终发展为枝状电树枝,曲率半径大的试样则大概率最终发展为丛状电树枝,丛状电树枝的放电量大于枝状电树枝。丛状电树枝的PRPD图正、负半周均类似于“翼形”,枝状电树枝正半周的放电形状表现为“三角形”,负半周形状表现为“翼形”。两种电树枝生长速率均表现为“快-慢-快”的特点,枝状电树枝生长速率大于丛状电树枝,在实际电缆中枝状电树枝的危害更大。

Electrical tree is a common phenomenon in XLPE cable, and there may be different scales of spike defects during the operation of cables. In this paper, the relationship between electrical tree growth morphology and partial discharge characteristics under different tip curvature radius was studied. The results show that the sample with small tip curvature radius will eventually develop into branch electrical tree under the tree initiation voltage, while the sample with large curvature radius will eventually develop into cluster electrical tree, and the discharge capacity of cluster electrical tree is greater than that of branch electrical tree. The positive and negative half cycle of PRPD diagram of the cluster electrical tree is similar to the“wing shape”. The discharge shape of the positive half cycle of the branch electrical tree is“triangle shape”, and the negative half cycle shape is“wing shape”. The growth rate of the two electrical trees shows the characteristics of“fast-slow-fast”. The growth rate of the branch electrical tree is higher than that of the cluster electrical tree, and the branch electrical tree is more harmful in the actual cable.