关于变电站接地网电阻值偏高问题的探讨

解决广西电网新建变电站接地网电阻值普遍偏高问题。通过进行全面剖析,总结出导致变电站接地电阻值偏高的原因有土壤表面接地电阻率测试结果不能反映土壤真实情况;热镀锌扁钢表面被氧化后导电性能下降;接地网施工工艺差等。为此提出了新的设计理念和施工方法,并提倡采用新工艺、新材料和科学的管理方法。采用镀铜扁钢替代热镀锌扁钢作为接地网材料,可有效降低接地网的电阻值。此外,根据变电站站址的地形地貌选择采用水平接地斜井方法,比盲目地采用接地极深井方法降低接地电阻的效果更明显。

Discussion on Problem of Higher Resistance Value in Substation Grounding Grid

The problem of generally higher resistance value in new substation grounding grid is solved. By the overall analysis, reasons of the higher resistance value in substation grounding grid are summarized, including that test results of the grounding resistivity of soil surface can not reflect the real situation of soil, the conductive performance of hot galvanized flat steel degraded after oxidation and the construction technology of grounding grid is worse and so on. New design concept and construction method are proposed, and the usage of new technology, new materials and scientific management method is advocated. Hot galvanized flat steel is replaced by copper plated flat steel as the material of grounding grid, which can effectively reduce the resistance value of grounding grid. The horizontal grounding of inclined shaft method is adopted based on the topography and geomorphology of substation location which has more obvious effect than the blindly used grounding electrode deep shaft method.