小电阻接地系统的方案设计及应用

随着电力电缆在城市配电网中的广泛采用,中性点经消弧线圈接地系统已暴露出其存在的不足,针对目前长沙市配电网的运行状况,对比小电阻接地系统和消弧线圈接地系统各自的优缺点.以罗家嘴变电站10kV系统为对象,研究10kV配电网采用中性点经小电阻接地系统的总体方案,主要分析小电阻阻值的选取、接地变压器容量的确定;重点实测和计算分析小电阻接地系统单相接地故障情况下故障点的跨步电压.目前该接地系统运行状况良好,为小电阻接地系统在长沙市配电网中的推广应用起到了重要的理论和工程实践指导作用.

Schematic design and application study on low resistance grounding system

With the widely use of power cable in distribution networks, the grounding system via arc suppression coil has exposed some limitation. According to the current operation state of Changsha distribution network, the advantages and disadvantages of the low resistance grounding system and arc suppression coil grounding system were analyzed in the paper. The novel schematic design was researched by using 10 kV Luojiazui power station mode/, which was adopted the low resistance grounding system to substitute the arc suppression coil grounding system. The selection of low resistance quantity and the earthing transformer＇s capacity was presented. The fault point step voltage on the condition of single phase fault was also calculated and analyzed. The new grounding system was realized and normal operation. Therefore, the research has important theoretical and project practical values to the low resistance grounding system popularization application in the Changsha city distribution power networks.