| 中性点接地可靠性 |
| 添加时间：2019/4/16 16:00:20 浏览次数： |
| 我国中压电网的供电系统中，大部分为小电流接地系统（即中性点不接地或经消弧线圈或电阻接地系统）。我国采用经消弧线圈接地方式已运行多年，但近几年有部分区域采用中性点经小电阻接地方式，为此对这两种接地方式作以分析，对于中性点不接地系统，因其是一种过度形式，其随着电网的发展最终将发展到上述两种方式。 Most of the power supply systems of medium voltage network in China are grounded by small current (i.e. neutral point is not grounded or grounded by arc suppression coil or resistance). China has been using arc suppression coil grounding mode for many years, but in recent years, some regions have adopted neutral point grounding mode through small resistance. This paper makes an analysis of these two grounding modes. For the neutral point non-grounding system, because it is an excessive form, it will eventually develop to the above two modes with the development of power grid. 中性点经小电阻接地方式世界上以美国为主的部分国家采用中性点经小电阻接地方式，原因是美国在历史上过高的估计了弧光接地过电压的危害性，而采用此种方式，用以泄放线路上的过剩电荷，来限制此种过电压。中性点经小电阻接地方式中，一般选择电阻的值较小。在系统单相接地时，控制流过接地点的电流在500A左右，也有的控制在100A左右，通过流过接地点的电流来启动零序保护动作，切除故障线路。 Neutral grounding through small resistance is adopted in some countries in the world, mainly in the United States. The reason is that the United States has overestimated the danger of arc grounding yesanpo.37ix.com.cnbaoding.75ix.cnmojusn.37ix.com.cnbxgxianwei.37ix.com.cnovervoltage in history. yuniguhua.71ix.comshijiazhuang.75ix.cnThis method is used to release excess charges on the lines to limit such overvoltage. In the neutral grounding mode with small resistance, the value of resistance is usually smaller. When the system is single-phase grounding, the current flowing through the grounding point is controlled at about 500A, and some are controlled at about 100A. The zero sequence protection action is started by the current flowing through the grounding point, and the fault line is removed. |
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