66 kV及以上高压电缆接地用同轴电缆和接地线选型

    Selection of Coaxial Cables and Grounding Wires for 66 kV and above High-Voltage Cable Grounding

    • 摘要: 针对66 kV 及以上单芯高压电力电缆接地系统用电缆选择问题,基于GB 50217—2018《电力工程电缆设计标准》与行业实践,探讨高压电缆接地用接地线不需要内外半导电屏蔽层及金属屏蔽层的原因。根据高压电缆非绝热状态下金属护层允许短路电流,计算不同非金属护套下导体允许的最小截面积。结果表明,接地电缆中采用聚氯乙烯(polyvinyl chloride,PVC)护套的理论允许导体最小截面积要比采用聚乙烯(polyethylene,PE)护套的理论允许导体最小截面积大6%。通过交叉互联接地系统与同轴电缆的协同应用,可同步实现感应电势均衡、施工可靠性提升和运维成本优化。研究通过理论分析与工程实践,系统探讨接地线选型、交叉互联结构设计及绝缘水平要求,供相关人员参考。

       

      Abstract: Regarding the selection of cables for grounding systems of 66 kV and above single-core high-voltage power cables, rationale behind not requiring internal and external semi-conductive shielding layers or metal shielding layers for grounding wires was analyzed, based on Design Standard for Power Engineering Cables (GB 50217—2018) and industry practice. The minimum conductor cross-section under various non-metallic sheaths was calculated according to the allowable short-circuit current on the metallic sheaths of high-voltage cables in a non-adiabatic state. Results indicated that the theoretical minimum conductor cross-section allowed by polyvinyl chloride sheath was approximately 6% larger than that allowed by polyethylene sheath. Through collaborative application of cross-connected grounding system and coaxial cables, it was possible to simultaneously achieve induced potential balancing, enhance construction reliability, and optimize operation and maintenance costs. The paper systematically discussed the selection of grounding wires, the design of cross-interconnection structures, and insulation level requirements through theoretical analysis, providing reference for engineering practice.

       

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