单芯电力电缆金属护层过电压保护器参数设计

Technical Parameters Design of Over Voltage Protector for Single-core Power Cable Shield Sheath

针对高压单芯电力电缆金属护层接地方式和金属护层过电压导致电力电缆线路载流量急剧下降,甚至发生运行故障,而目前国内外还没有如何合理选取单芯电力电缆金属护层过电压保护器参数相关标准或规程的现状,依据GB50217《电力工程电缆设计规范》、DL/T401《高压电缆选用导则》和DL/T5221《城市电力电缆线路设计技术规定》标准,结合大量现场运行经验和事故原因分析结果,采用理论计算和试验验证相结合的研究方法,探讨了单芯电力电缆金属护层过电压保护器参数的优化设计。理论计算和试验验证结果表明:设计的电缆金属护层保护器的8/20μs标称放电电流和标称放电电流下的残压等电性参数符合相关标准的技术要求,能够满足单芯电力电缆线路金属套过电压保护和保护接地持续安全可靠运行的实际需要。

To design and optimize the technical parameters of over voltage protector for single-core power cable metal shield grounding, the rules and methods of design and optimization of over voltage protector for cable metal shield grounding were discussed based on national standards of China such as GB 50217 Design Criterion of Power Cables for Electrical Engineering, DL/T 401 Guide to the Selection of High Voltage Cables and DL/T 5221 Technical Rule for Design of Urban Power Cables as well as practice experience of long-term operation of power cable lines. Furthermore, lightning impulse test and large current impulse test were used for validating reliability and preponderance of the protector design. The results of theoretical analysis and tests prove that the over voltage protector for cable metal shield grounding designed by the rules can satisfy the technical requirements of the standards and meet ：the practical demands of power cable lines operation safely and reliably.