20kV配电网应用及中性点接地方式研究

Application of 20kV distribution network and study on the selection of neutral point grounding modes

随着经济发展,采用20kV配电网相比10kV电压等级配电具有越来越多的优越性,如提高电力系统的稳定性、电能质量和运行的经济性能,降低电网的投资等。而在20kV配电网进行建设、升压、改造时,中性点接地方式成为关键技术问题之一,对设备选型、系统运行及继电保护等具有重大的影响。本文首先对采用20kV电压等级的优势与10kV、35kV进行了比较,然后分析和探讨了20kV配电网的中性点不接地、经消弧线圈接地、小电阻接地和灵活接地方式等问题,并提出了相应的建议,最后总结了国内外20kV配电网中性点接地式的现状及发展趋势,以期为将来20kV配电网的广泛使用提供技术参考。

With the economic development, adopting 20kV distribution network has more and more advantages compared with 10kV voltage distribution, such as improving the stability of power system, power quality and economy of operation, and reducing the investment of power grid. However, In the 20kV distribution network to build, boost, transformation, the neutral point grounding has become one of the key technical issues, the equipment selection, system operation and relay protection has a significant impact. In this paper, firstly, the advantages of using 20kV voltage level are compared with 10kV and 35kV. Then, analyzed and discussed the neutral point of 20kV distribution network is not grounded, grounding through peterson coil; grounding through small resistance; flexible grounding. Finally, the status quo and development trend of neutral point grounding of 20kV distribution network both at home and abroad are summarized, providing a technical reference for the widespread use of 20kV distribution network in the future.