配电网接地故障保护若干问题的探讨

Discussion on Several Problems of Earthing Fault Protection in Distribution Network

中国各电网公司均提出要快速就近隔离配电网接地故障,以减少触电与大面积停电事故,然而对中压配电网的不同接地方式及其接地故障保护方法的优缺点还有较大的争议,还没有形成共识,不利于形成优化的接地故障处置方案。文中总结国内外经验,对比了不同接地方式及其接地故障保护方法的技术特点,指出接地方式会影响接地故障的检测标准与保护动作正确率的统计结果;分析了小电流接地系统改为低阻接地、消弧线圈并低阻接地以及采用主动干预消弧时存在的问题,介绍了暂态接地保护技术及其应用情况;针对不同类型的配电网,给出接地方式与接地保护方法选择的建议。

Power grid companies in China propose to quickly and closely isolate the earthing fault of distribution networks to reduce electric shock and large-scale blackout. However, there are great controversies on different earthing modes and the advantages and disadvantages of earthing fault protection methods for medium-voltage distribution network, and no consensus has been reached, which is not conducive to the formation of an optimized earthing fault disposal method. In this paper, experiences at home and abroad are summarized. Technical characteristics of different earthing modes and their earthing fault protection methods are compared. It is pointed out that the earthing mode will affect the detection standard of earthing fault and the statistical result of protection accuracy. The problems existing in the conversion of low current grounding system to low resistance grounding, arc suppression coil parallel low resistance grounding and active intervention arc suppression are analyzed. Transient earthing protection technology and its application are introduced. For different types of distribution network, the selection of earthing mode and earthing protection method is suggested.