Survey statistics show that the main faults of high voltage switchgear are as follows:
(1) Rejection or misoperation failure: This type of fault is the main fault of the high voltage switchgear. The reasons can be divided into two categories: one is caused by mechanical failure of the operating mechanism and the transmission system; the other is due to Caused by electrical control and auxiliary circuits.
(2) Breaking and closing faults: These faults are caused by the main body of the circuit breaker. For oil-less circuit breakers, the main performance is short-circuit of fuel injection, burnout of arc-extinguishing chamber, insufficient breaking capacity, and closing Explosion, etc. For the vacuum circuit breaker, it is characterized by air leakage of the arc extinguishing chamber and the bellows, reduction of vacuum, re-ignition of the capacitor capacitor group, and cracking of the ceramic tube.
(3) Insulation fault: performance of external insulation to ground flashover breakdown, internal insulation to ground flashover breakdown, phase-to-phase insulation flashover breakdown, lightning overvoltage flashover breakdown, porcelain bottle casing, capacitor casing flashover , pollution flash, breakdown, explosion, lifting rod flashover, CT flashover, breakdown, explosion, porcelain bottle breakage.
(4) Current-carrying fault: The main cause of current-carrying fault at 7.2~12 kV voltage level is that the contact of the switchgear isolation plug causes the contact to melt.
(5) External forces and other faults: including foreign object impact, natural disasters, small animal short circuits, etc.