Study On The Cause Of 10kV Capacitor Fault In Ji'an Substation

In recent years, individual transformer substation's capacitors break down frequently. The Phenomenon of capacitor bursting and fuse exploding appears. the accident cause economic lose and threat to the electrical network and the running person.This paper mainly carried out the studies as follows. firstly, this paper analysizes the influence on the life of capacitor by the following factors as the over-voltage when the capacitor switches on/off,inrush current when the capacitor switches on, over-voltage due to the harmonics, ambient temperature and so on. secondly using the EMPT simulation software analysizes the influence on capacitor by the switching over-voltage and the harmonics. Thirdly,the current, harmonics and voltage is monitored and measured in time by online monitoring system on shunt capacitor. the current, harmonics and voltage can be instantly retrieved. And the state parameter of the capacitor and the data and waveform when it is fault is monitored in time. The major fault cause is accurately obtained by analysizing the fault data and waveform monitored and measured by the online-monitoring system.The findings indicate that capacitor fault is due to high electric-field intensity and the overheated influence. If the capacitor operate in the hot environment and in the overvoltage situation for a long time, the capacitor interior weak part will penetrate, which caused capacitor's breakdown.