The cross-linked polyethylene insulated cables with corrugated aluminium-sheathed are widely used in urban power systems. Recently, a new type of power cable fault has emerged, primarily due to defects in the buffer layer. However, there is a notable lack of effective evaluation methods for these defects in high-voltage (HV) cables. Initially, a theoretical analysis of the gas generation mechanism in the cable buffer layer was conducted, identifying distinct gas products at different stages. Subsequently, the diffusion kinetics of gas within the cable was studied, highlighting the importance of gas in determining the state of the buffer layer. The authors then collected and analysed 60 sets of buffer layer gases from two operational 110 kV HV cables using gas chromatography technology. Combining these results with the findings from on-site inspections, the characteristic gas components and concentration distribution under various defect conditions were summarised. The results found higher concentrations of CH₄ in normal cables and defective cables, while there are higher concentrations of H₂, CO and CO₂ in defective cables, and the oxygen content decreases. The discoveries made in this research may offer a new approach for assessing the state of the cable buffer layer.

中文翻译：

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高压交联聚乙烯电缆缓冲层产气量分析

交联聚乙烯绝缘波纹铝护套电缆广泛应用于城市电力系统。近年来，出现了一种新型电力电缆故障，其主要原因是缓冲层存在缺陷。然而，针对高压（HV）电缆中的这些缺陷，明显缺乏有效的评估方法。首先，对电缆缓冲层中的气体生成机制进行了理论分析，识别了不同阶段的不同气体产物。随后，研究了电缆内气体的扩散动力学，强调了气体在确定缓冲层状态中的重要性。然后，作者使用气相色谱技术从两条运行的 110 kV 高压电缆中收集并分析了 60 组缓冲层气体。结合现场检查结果，总结了各种缺陷条件下的特征气体成分和浓度分布。结果发现，正常电缆和缺陷电缆中CH _{4浓度较高，而缺陷电缆中H 2}、CO和CO ₂浓度较高，氧含量降低。这项研究的发现可能为评估电缆缓冲层的状态提供一种新方法。