清原抽蓄电站厂用电系统中性点接地方式研究

Research on neutral point grounding mode of power systemin Qingyuan Pumped Storage Power Station

摘要

我国抽水蓄能电站10 kV厂用电系统长期以来采用中性点不接地的运行方式，随着厂用电设备容量的不断增加，电缆化率不断提高，发生单相接地故障后，由于故障电容电流过大，电弧往往不能自熄，单相接地故障升级为相间短路事故的情况时有发生。首先对目前主流的中性点不接地、中性点经消弧线圈接地、中性点经小电阻接地三种接地方式原理进行研究，分析比较各接地方式的优缺点，并结合清原抽水蓄能电站厂用电设计原则和各设备实际参数，研究得出最适合电站运行情况的中性点接地方式。

Abstract

The 10kV plant power system of pumped-storage power station in China has been operating with neutral point ungrounded for a long time. With the continuous increase of the capacity of plant power equipment, the cabling rate continues to rise. After single-phase grounding fault occurs, the arc often fails to self-quench due to the fault capacitor current being too large, and the single-phase grounding fault is often upgraded to an inter-phase short circuit accident. This paper studies the principle of three main grounding method: neutral ungrounded, neutral grounding through arc suppression coil and neutral grounding through little resistance, analyzes and compares the advantages and disadvantages of each grounding method, and studies the neutral grounding method which is most suitable for the operation of the power station in combination with the design principle of power consumption in Qingyuan Pumped Storage Power Station and the actual parameters of each equipment.

关键词

抽水蓄能电站 / 10 kV厂用电系统 / 中性点接地方式 / 单相接地故障 / 小电阻接地

Key words

pumped storage power station / 10 kV plant power system / neutral ground mode / single-phase earth fault / little resistance grounded