SF6 Circuit Breaker in Urdu/Hindi | SF6 Circuit Breaker Working Operation | ElectricalTraining Center

Sulphur Hexafluoride (SF6) Circuit Breaker, A circuit breaker in which SF6 under pressure gas is used to extinguish the arc is called SF6 circuit breaker. SF6 (Sulphur hexafluoride) gas has excellent dielectric, arc quenching, chemical and other physical properties which have proved its superiority over other arc quenching mediums such as oil or air. The SF6 circuit breaker is mainly divided into three types • Non-puffer piston circuit breaker • Single- puffer piston circuit breaker. • Double-puffer piston circuit breaker. The circuit breaker which used air and oil as an insulating medium, their arc extinguishing force builds up was relatively slow after the movement of contact separation. In the case of high voltage circuit breakers quick arc extinction properties are used which require less time for quick recovery, voltage builds up. SF6 circuit breakers have good properties in this regards compared to oil or air circuit breakers. So in high voltage up to 760 kV, SF6 circuit breakers is used. WORKING OF SF6 CIRCUIT Breaker, During the normal condition contacts of circuit breaker remains closed and contacts are surrounded by SF6 gas at a pressure of 2.8 kg/cm². During the fault condition, moving contact of circuit breaker is pulled and an arc struck between them. This movement of moving contact opens the valve which permits the SF6 at 14 kg/cm² pressure to flow from reservior to the arc interruption chamber. This high pressure flow of SF6 gas rapidly absorbs the free electrons present in the arc. The result is that the medium between the contacts quickly builds up the high dielectric strength and arc gets extinguished. After the operation of breaker, the valve is closed by the spring action. ADVANTAGES OF SF6 CIRCUIT Breaker, 1. Because of excellent arc quenching property SF6 gas, such circuit breakers have very short arcing time. 2. Dielectric Strength of SF6 gas is very high, so such breaker can interrupt larger current. 3. Since the SF6 is non-inflammable, so there is no risk of fire. 4. SF6 gas does not contain any carbon content so there is no carbon deposits 5. SF6 circuit breaker provides the noiseless operation unlike Air blast circuit breaker. 6. SF6 breakers are completely enclosed and sealed from atmosphere, so there are no explosion hazards. DISADVANTAGES OF SF6 CIRCUIT BREAKER 1. SF6 breakers are costly due to the high cost of SF6 gas. 2. SF6 gas has to be reconditioned after every operation of circuit breaker, so additional equipment is required for this purpose. #Circuitbreaker #SF6circuitbreaker #Breaker

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