Finite Element Study on Electric Field Distortion and Maxwell Stress Distribution Characteristics of XLPE Insulation Considering Water tree under Different Conditions

Abstract

Water tree is one of the important factors that affect the service life of XLPE insulation cable and seriously threaten the safety of cable operation. In order to study the electric field distortion and Maxwell stress distribution characteristics considering water tree under different circumstances, the paper takes position, length and dispersion into consideration, and then a cable insulaton model with water tree defects under different conditions is established in the finite element simulation software. By applying a fixed voltage on both sides of the insulation, the axial electric field intensity of water tree is scanned, the maximum electric field intensity in the insulation is counted, and the influence characteristics of water tree on the electric field distortion of cable XLPE insulation are studied. At the same time, the Maxwell stress caused by electric field distortion is calculated, and the maximum axial stress of water tree is extracted and analyzed. The results show that when the size is approximately the same, the electric field distortion caused by Inner dispersed water tree is significantly higher than that on Outer dispersed water tree, and the electric field distortion caused by the Butterfly-shaped water tree whose size is approximately twice that of the dispersed water tree is between the two; The effect of length and dispersion on electric field distortion varies with water tree type and location.In terms of stress, the Maxwell stress caused by the Inner dispersed water tree is greater than the Outer dispersed water tree with approximately the same size and the Butterfly-shaped water tree with approximately twice the size. The increase of length is conducive to the reduction of the maximum Maxwell stress caused by the dispersed water tree.