According to the arc extinguishing medium used by the circuit breaker, it can be divided into the following types:

1. Air circuit breaker

The air circuit breaker uses compressed air as the arc extinguishing medium, which is fireproof, explosion-proof, non-toxic, non-corrosive and easy to use. The air circuit breaker belongs to the other energy type circuit breaker, which relies on compressed air to blow the arc to cool it. When the arc reaches the zero value, the ions in the arc track are quickly blown away or combined to achieve arc extinguishing. Air circuit breakers have strong breaking capacity and short breaking time, but have complex structures, high process requirements, and high consumption of non-ferrous metals. Therefore, air circuit breakers are generally used in power systems of 110KV and above.

2. Oil circuit breaker

The oil circuit breaker uses insulating oil as the arc extinguishing medium. It can be divided into more oil circuit breakers and less oil circuit breakers. In the multi-oil circuit breaker, oil is not only used as an arc extinguishing medium, but also as an insulating medium, so the oil consumption is large and the volume is large. In the oil-less circuit breaker, the oil is only used as the arc extinguishing medium, so the oil consumption is small, the volume is small, and the steel consumption is small.

3. Vacuum circuit breaker

Vacuum circuit breakers extinguish arcs in a high vacuum. Arcs in a vacuum are formed in metal vapors that evaporate from the electrodes as the contacts separate. The ions and electrons in the arc diffuse rapidly into the surrounding space. When the arc current reaches zero value, the number of particles between the contacts that disappear due to diffusion exceeds the number generated, and the arc cannot be maintained and extinguished. The vacuum circuit breaker has strong breaking capacity, short breaking time, small size, small footprint, no noise, no pollution, long life, frequent operation and long maintenance cycle. Vacuum circuit breakers have gradually been widely used in power distribution systems in my country. In addition, there are magnetic blowing circuit breakers and self-generating gas circuit breakers, which have the advantages of fireproof and explosion-proof, easy to use and so on. However, the rated voltage is generally not high and the breaking capacity is not large, so it is mainly used as a circuit breaker for power distribution.

4. Sulfur hexafluoride (SF6) circuit breaker

SF6 circuit breaker uses SF6 gas with excellent arc extinguishing ability and insulating ability as arc extinguishing medium, which has the advantages of strong breaking capacity, fast action and small size, but it consumes more metal and is expensive. In recent years, SF6 circuit breakers have developed rapidly and have been widely used in high-voltage and ultra-high-voltage systems. In particular, the enclosed combined electrical appliances with SF6 circuit breakers as the main body are an important development direction of high-voltage and ultra-high-voltage electrical appliances.