What is SF6 circuit breaker?
Sulphur hexafluoride (SF6) gas is used as the arc extinction medium in such circuit breakers. SF6 gas has a significant propensity to absorb free electrons since it is an electro-negative gas. Under a high pressure flow of SG6 gas, the breaker's contacts are open, and an arc forms between them.
The gas quickly absorbs the conducting free electrons in the arc to create comparatively stationary negative ions. This loss of conducting electrons in the arc quickly builds up enough insulation strength to extinguish the arc.
Advantages of SF6 circuit breaker.
➤ Such circuit breakers have a very low arcing time due to the better arc quenching capabilities of SF6.
➤ These breakers can interrupt significantly larger currents because SF6 gas has a dielectric strength that is two to three times greater than that of air.
➤ Due to their closed gas circuit and lack of emission to the atmosphere, SF6 circuit breakers operate quietly compared to air blast circuit breakers.
➤ Since SF6 breakers are completely enclosed and moisture-proof, they are especially useful in environments where there is a risk of explosion, such as coal mines.
➤ The SF6 breakers require less auxiliary equipment, have a small foundation requirement, and have low maintenance costs.
➤ There is no moisture issue because of the closed gas enclosure, which keeps the interior dry.
➤ These breakers are not at risk of catching fire because SF6 gas is not flammable.
➤ Since there is no carbon deposits, tracking and insulation problems are eliminated.
Disadvantages of SF6 circuit breaker.
➤ Since SF6 gas has to be reconditioned after every operation of the breaker, additional arrangement is required for this purpose.
➤ Due to the high cost of SF6 gas, breaker costs are excessive.
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 Circuit Breaker : Advantages and disadvantages.){kind=link}
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