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

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.

Keywords

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