Cause and Treatment of Capacitor Explosion(I)

Cause analysis and treatment.

1. High ambient temperature.

The reactive power compensation panel is installed in the 400V switch room. There are 8 switchgear cabinets in the room, but the area is only 30m2. The opposite is the SZ7-800kVA 35kV/0.4 transformer room. The overall ventilation conditions are poor. The temperature of the switch room in the hot summer is above 48 ℃. It can be seen that high ambient temperature is one of the causes of capacitor explosion. The compensation panel shall be moved to the single ventilation control room and shall be affixed to the capacitor housing with a wax sheet (temperature indicator), from which the duty officer may indirectly monitor the temperature of the capacitor medium.

2.Extremely unstable voltage  

We can see from the formula QC=2 π fCV2 that the reactive power capacity of the capacitor is proportional to the square of the voltage. When the voltage decreases, the reactive power capacity of the capacitor will be reduced in proportion to the square of the voltage, that is, the capacity of the capacitor will not be fully utilized. When the operating voltage increases, the temperature rise of the capacitor will be increased, and even the thermal balance of the capacitor will be destroyed, which will cause the capacitor to explode. Therefore, the national standard states that capacitors are allowed to operate for a long period of time at a rated voltage of 1. 1 times, but the operating time under a rated voltage of 1. 15 times per 24 hours shall not exceed 30min.