Sulfur hexafluoride gas circuit breakers can be divided into the following three categories according to their different arc extinguishing modes:

　　(1)double voltage sulfur hexafluoride gas circuit breaker.The interior of the double pressure sulfur hexafluoride circuit breaker can be divided into two areas of high pressure and low pressure:the SF6 gas in the low pressure area is mainly used as the internal insulation of the circuit breaker,and its pressure is 0.304~0.507MPa;SF6 gas in high pressure area is only used in the circuit breaker opening process,open the blow valve low pressure area vent,forming high pressure air flow between the nozzle of the arc extinguishing chamber and the contact to extinguish the arc,the pressure is 1.013t1.520MPa.The gas sprayed from the high pressure area to the low pressure area is returned to the high pressure area through the gas circulation system and the compressor.The double-voltage sulfur hexafluoride circuit breaker has large breaking capacity but complex structure.In particular,in order to prevent high pressure SF6 gas from liquefaction at low temperature,it is necessary to add a complex circulating heating device.

　　(2)single voltage sulfur hexafluoride circuit breaker.Single voltage sulfur hexafluoride gas circuit breakers have only one lower pressure system,namely 0.3 0 4-0.507MPa SF6 gas as the internal insulation of the circuit breakers.During the circuit breaker disconnection,the piston is driven by the moving contact to pressure or draw air to form air flow to blow out the arc.When the breaker breaking operation is completed,the gas pressure action is also stopped,and the low pressure gas state is restored between the contacts.Single pressure sulfur hexafluoride circuit breaker structure is relatively simple,so easy to manufacture,and the gas pressure is low,SF6 gas at low temperature and no liquefaction problem,so the work reliability is higher,maintenance is easier.

　　(3)self-energy arc extinguishing type SF6 circuit breaker.Self-energy arc extinguishing high purity sulfur hexafluoride still uses SF6 gas 0.304-0507MPa as the internal insulation of the circuit breaker,and in the process of breaking the circuit breaker,the energy generated by the arc is used to self-blow SF6 gas to quench the arc.Its structure is simpler than the single pressure type,but the breaking capacity is small.Double voltage type is generally 110kV class above sulfur hexafluoride circuit breaker;Single voltage type is generally 35-110kV sulfur hexafluoride circuit breaker.