Abstract: Aiming at the problem of high voltage XLPE cable buffer layer ablation faults causing a big impact on the safe operation and maintenance of cables, the buffer layer ablation fault detection technology based on characteristic gases is proposed. By building the XLPE cable buffer layer simulated ablation experimental platform and cable true type experimental platform, the characteristic gases and their ablation characteristics generated by the cable buffer layer ablation faults are studied, focusing on the buffer layer moisture rate, the buffer layer thickness, and the buffer layer applied current RMS value on the buffer layer characteristic gases. The results show that the magnitude of current applied to the buffer layer is the most important factor affecting the concentration of characteristic gases, and the buffer layer is more prone to ablation under moisture conditions,with smaller suffer layer thickness being more prone to ablation. Through the practical application of two cables with buffer layer ablation faults, the results show that the analysis of the buffer layer gas composition can be used to diagnose whether or not buffer layer ablation faults have occurred in the cable segment and the severity of faults, which verifies the feasibility of buffer layer ablation fault diagnostic technology based on characteristic gases.

Key words: XLPE cable, characteristic gas, buffer layer, fault detection