Study on the Ablation Mechanism of the Buffer Layer in High-Voltage XLPE Cables

Frequent ablation incidents within the buffer layer of high-voltage cross-linked polyethylene (XLPE) cables pose significant risks to power grid stability. This study delves into the ablation mechanism specifically within the buffer layer of corrugated aluminum sheathed cables, aiming to furnish theoretical and empirical foundations for fault diagnosis. An electro-thermal coupled finite element model was developed to simulate the localized temperature rise characteristics induced by radial capacitive current concentration. Complementary simulated ablation experiments systematically investigated the influence of pressure, current magnitude, and moisture ingress on ablation severity, elucidating the underlying damage pathways. Key findings reveal that localized high resistance due to poor contact concentrates the radial current, leading to sustained Joule heating accumulation and consequent structural degradation. Ablation severity exhibits a strong dependence on the moisture content of the water-blocking buffer material, applied current density, and interfacial pressure. Critically, moisture and the formation of conductive white powder are identified as primary accelerants of the ablation process. This work provides actionable insights for optimizing cable design, enhancing predictive maintenance strategies, and bolstering grid reliability.