The frequent occurrence of breakdown accidents caused by the erosion of the buffer layer of high-voltage cables poses a serious threat to cable operation safety. While existing research primarily focuses on the erosion and damage of the buffer layer itself

the process and mechanism of erosion defects developing towards the cable insulation shield remain unclear. This article provides a comprehensive summary of the damage characteristics of the insulation shield caused by white powder in an actual ablative fault cable. The analysis includes a three-dimensional finite element simulation of high voltage cable to investigate the damage mechanism of the insulation shield by white powder

along with verification through simulation tests of the insulation shield damage process and actual cable simulation ablation tests. The findings indicate that the primary damage characteristics of white powder on the insulation shield are predominantly embedded damage

resulting from current thermal effects at the edge of the white powder and pressure. In terms of axial direction

current density is concentrated at the edge of the white powder

promoting electrochemical corrosion on the buffer layer surface and formation of continuously distributed white powder strips. Radially

temperature rise due to critical current density exceeding 185 A/m2 leads to thermal decomposition of buffer layer and melting temperature exceeding that for insulation shield layer. Under cable self-weight action

gradual penetration into buffer layer occurs leading to surface damage on insulation shield. These simulation results align well with laboratory-based simulation tests on insulation shield damage process and actual ablative fault cable disintegration

thus validating rationality in this paper's analysis results. The research outcomes presented here hold significant implications for elucidating development mechanisms underlying ablative defects within buffer layers.