Fault performance and reasons of high and low voltage switchgear

The faults of high-voltage switchgear mainly include the following categories:

1. Refusal to act and malfunction: This kind of fault is the main fault of the high-voltage switchgear.

The reasons can be divided into two categories: 1. It is caused by the mechanical failure of the operating mechanism and the transmission system. 2. It is caused by electrical control and auxiliary circuits.

2. Breaking and closing faults: This type of fault is caused by the circuit breaker itself. For low-oil circuit breakers, the main manifestations are fuel injection short circuit, arc extinguishing chamber burning, insufficient breaking capacity, and explosion when closing and closing. For vacuum circuit breakers, it is manifested as air leakage from arc extinguishing chamber and bellows, reduction of vacuum, re-ignition of cut capacitor bank, rupture of ceramic tube, etc.

3. Insulation failure: manifested as flashover breakdown of outer insulation to ground, flashover breakdown of inner insulation to ground, interphase insulation flashover breakdown, lightning overvoltage flashover breakdown, flashover of porcelain bottle bushings, capacitor bushings, Pollution flashover, breakdown, explosion, lifting rod flashover, CT flashover, breakdown, explosion, porcelain bottle breakage, etc.

4. Current-carrying faults: The main reason for current-carrying faults at voltage levels of 7.2 to 12kV is that the isolation plugs of the switch cabinet are in poor contact, causing the contacts to melt.

5. External force and other faults: including foreign object impact, natural disasters, short circuit of small animals, etc.