Discussion about Substation Grounding for Medium-voltage

Low-resistance Grounding System

Guo Fengwen（Nanjing Municipal Engineering Design and Research Institute Co.，Ltd.，Nanjing 210008，China）

Abstract When 10（20）kV electrical source side neutral point adopts low-resistance grounding system，the existing problems of the high-voltage equipment protective grounding and low-voltage neutral point system grounding divided network settings in the distribution substations are analyzed. It is considered that this measure is limited by the choice of low-voltage grounding type; when the ground fault occurs inside the low-voltage distribution cabinet，the dangerous contact voltage is unable to be eliminated；and the provisions of the grounding divided network setting are difficult to be implemented and there may be hidden dangers and so on. Thus the use of common grounding and related preventive measures are put forward.

Key words Protective grounding System grounding Grounding divided network settings Common grounding

 

摘 要 对 10（20）kV电源侧中性点采用小电阻接地系统的配电变电所中，高压设备的保护接地和低压中性点系统接地分网设置存在的问题进行了分析。认为这一措施存在低压接地型式选择受限；当低压配电柜内发生接地故障时，可能无法消除危险接触电压；以及接地分设规定执行困难且存在隐患等问题。进而提出采用共用接地及相关防范措施的意见。

关键词 保护接地   系统接地   接地分网设置   共用接地