Study on the ablation process and failure mechanism of the buffer layer in high-voltage XLPE cable

In recent years, the frequent occurrence of ablation faults in the buffer layers of high-voltage cross-linked polyethylene (XLPE) cables has significantly undermined the stability of power grid operations. However, existing research cannot fully explain the failure mechanism and transformation of related physical and chemical properties of high-voltage cable buffer layer. To address this, the paper have constructed an integrated analysis framework that includes multiphysics field simulations, an equivalent electrical network model, and simulated ablation experiments to comprehensively reveal the complete ablation failure mechanisms. Firstly, this study conducted a comparative analysis of the voltage distribution and temperature changes in the buffer layer using electro-thermal coupling simulations and an equivalent electrical network model. This analysis provides a detailed study of the dynamic development process of buffer layer ablation and identifies key electrical parameters. Subsequently, it verified the accuracy of the simulations through experiments on temperature variation characteristics, changes in hydrogen content, and other gas concentrations by constructing a simulated buffer layer ablation experimental platform. Finally, based on the study of the mechanisms of the buffer layer ablation failure process, this study divided it into three stages: initial electrochemical corrosion, appearance of white powder, and the onset of ablation discharge in the buffer layer. The comparison of experimental results with simulation data from the first two stages further validated the effectiveness and robustness of our analysis framework. In summary, this study provides a comprehensive analysis of the failure process in high-voltage cable buffer layers through simulation and experimental validation. This study provides a methodological basis for preventing cable ablation faults and detecting and evaluating the status of high-voltage XLPE cable buffer layers.