SF6 circuit breaker is one kind of switch equipment by using SF6 gas as insulation medium and arc-extinguishing medium. The insulation and arc-extinguishing medium is highly better than oil circuit breaker.
35KV SF6 circuit breaker is outdoor high voltage electrical instrument of 3 phase 50Hz. It is available for 40.5kv distribution system control and protection, and also can be used as network interconnecting circuit breaker and on or off capacitor. It adopts compressed-air type arc extinguish chamber, which arc time is short and long service life.
35KV SF6 circuit breaker structure is ceramic column type, 3 phase independent with compressed-air arc distinguish chamber, 3 phase air is connected by copper tube. Breaker is composed of support porcelain insulator, current transformer, arc distinguish chamber, absorber, transmission box, coupling, bottom frame and spring operation mechanism.
1.Porcelain sleeve: it is insulator and support for connection between main loop and power system. Due to getting through with housing of breaker, it belongs to part of pressure vessel, so it is high strength and good sealing.
2.Arc distinguish chamber is composed of static contactor, dynamic contactor, porcelain sleeve, air cylinder and sprayer.
3.Absorber: material is aluminum alloyed vessel. It has F-03 molecular sieve inside. Its effect is to absorb moisture in the SF6 gas and low fluoride born due to electric arc effect.
Its function is to transfer horizontal movement output to vertical movement of breaker contactor by external connecting lever, shaft and internal connecting lever. There are seal rings on each side of shaft. Buffers are installed up and down of external connecting lever. Self sealing valve is interface for breaker and pipelines air-in and air-out, which is used to measure breaker moisture.
5.Arc distinguish principle
The cabin is single pressure air pressing structure: that is SF6 gas of 0.4-0.5Mpa inside breaker. During switch off, movable air will be effect on static seat, internal air is compressed, and there is air difference with external air. High pressure SF6 gas blow arc to force arc distinguished when current is zero. Once breaking, this pressure will be disappeared and internal and external pressure will be balanced. Due to cut-off valve on the seat, switch on pressure is very small.