According to the interrupting medium used in circuit breakers, they can be divided into the following types.

Air Circuit Breaker

Air circuit breaker is to use compressed air as an arc extinguishing medium, such media fire, explosion-proof, non-toxic, non-corrosive, easy to access. Air circuit breaker belongs to his energy circuit breaker, relying on compressed air to blow the arc to make it cool, when the arc reaches zero value, the ion in the arc channel will quickly blow away or make it compound and achieve arc extinguishing. Air circuit breakers have strong breaking capacity and short breaking time, but the structure is complex, high technology requirements, and more non-ferrous metal consumption, therefore, air circuit breakers are generally used in the power system of 110KV and above.

Oil Circuit Breaker

Oil circuit breaker is insulating oil as the interrupting medium. It can be divided into multi-oil circuit breakers and oil less circuit breakers. In multi-oil circuit breakers, oil is used not only as an interrupting medium, but also as an insulating medium, so the amount of oil used is large and voluminous. In less oil circuit breakers, oil is only used as the interrupting medium, so the volume of oil used is small and consumes less steel.

Vacuum circuit breaker

Vacuum circuit breaker is in a high vacuum to extinguish the arc. The arc in the vacuum is formed in the metal vapor that evaporates from the electrodes when the contacts are separated. The ions and electrons in the arc rapidly spread to the surrounding space. When the arc current reaches zero value, the number of particles between the contacts disappearing due to diffusion exceeds the number generated, the arc cannot be maintained and extinguished. Vacuum circuit breaker has strong breaking capacity, short breaking time, small volume, small occupied area, no noise, no pollution, long life, can be operated frequently and long maintenance cycle. Vacuum circuit breakers are now gradually being widely used in China's power distribution system. In addition, there are magnetic blowing circuit breakers and self-produced gas circuit breakers, which have the advantages of fire and explosion-proof, easy to use, etc.. However, the general rated voltage is not high, the breaking capacity is not large, mainly used as circuit breakers for power distribution.

Sulfur hexafluoride (SF6) circuit breakers

SF6 circuit breakers use SF6 gas with excellent interrupting ability and insulation ability as the interrupting medium, which has the advantages of strong breaking capacity, fast action and small size, but more metal consumption and more expensive. In recent years, SF6 circuit breakers have developed rapidly and are widely used in high-voltage and ultra-high-voltage systems. Especially the closed combination electrical apparatus with SF6 circuit breaker as the main body is an important development direction of high-voltage and ultra-high-voltage electrical appliances.