青藏铁路110kV输变电工程五道梁和沱沱河变电站的接地系统设计

为青藏铁路供电的110kV沱沱河和五道梁变电站地处高寒永冻地区,如何在高寒永冻地区进行接地系统设计对变电站的建设十分重要。通过测试二次电缆和二次设备的绝缘耐受特性,提出可将地电位升高提高到5kV。采用电磁场数值计算方法对分层土壤中接地系统的电气参数进行计算, 分析比较了各种可行的高寒冻土地区接地系统的设计方案, 讨论了深垂直接地极的布置规律、水平地网的埋设深度、接地系统的均压优化布置对接地系统接地电阻、接触电压和跨步电压的影响。最终得出了坨坨河和五道梁两变电站的接地系统设计方案,并总结归纳了高寒冻土地区变电站接地系统的设计规律。

Grounding System Design of Wudaoliang and Tuotuohe Substations for 110kV Power Transmission Engineering of Qinghai-Tibet Railway

The 110kV Tuotuohe and Wudaoliang substations supplying power for Qinghai-Tibet railway locate in arctic-alpine permafrost area, so it is very important for the construction of substation how to design grounding system in arctic-alpine permafrost area. By means of measuring the insulation withstand properties of secondary cables and devices, it is proposed that the ground potential rise can be increased to 5kV. Applying the numerical analysis method of electromagnetic field to electrical parameter calculation of grounding system in layered soil, various feasible design schemes for grounding system in arctic-alpine permafrost area are analyzed and compared, the arrangement regularity of deeply-buried vertical grounding electrodes, the burial depth of horizontal grounding grid, the influence of grounding system's optimal arrangement on grounding resistance, touch voltage and step voltage of grounding system are researched. Eventually the grounding system design scheme for Tuotuohe and Wudaoliang substations is obtained. At the same time, the regular patterns of grounding system design in arctic-alpine permafrost area are summarized and induced.