Types Of sf6 Circuit Breaker

sf6 Circuit Breaker :

This is one of the most popular breaker from different Circuit Breaker Types. sf6 circuit breaker is equipped with separated poles each having its own gas.In all types of the circuit breakers,gas pressure is 2 bars.Even if the pressure drops to 1 bar,there will not be any change in the breaking properties of the circuit breaker due to the superior features of sf6.During arcing,the circuit breaker maintains a relatively low pressure(max 5-6 bars)inside the chamber and there will be no danger of explosion and spilling of the gas around.Any leakage from the chamber will not create a problem since sf6 can undergo considerable decomposition,in which some of toxic products may stay inside the chamber in the form of white dust.If the poles are dismantled for maintenance,it needs special attention during removal of the parts of the pole.This type of maintenance should be carried out only by the experts of the manufacturer.

Types Of sf6 Circuit Breaker :
There are three types of sf6 circuit breakers:

1. Self-blast SF6 circuit-breakers

2.Double-pressure SF6 circuit-breakers

3. Puffer-type SF6 circuit-breakers


Self-blast Sf6 Circuit Breaker :

In this type of  circuit-breaker there interrupting chambers are divided into two main compartments with the same pressure (around 5 atm). When the arc interruption happens, the gas pressure in the arcing zone is heated resulting in high pressure. This high pressure gas from the other compartment then blasts into the arcing zone and in the meantime cools the arc column. Finally, the arc is extinguished. This type of circuit-breaker is normally used in high voltage levels up to 123 kV.

Double-pressure SF6 circuit-breakers :

Double-pressure Sf6 circuit breaker works on principles similar to air-blast circuit-breakers. The contacts in this breaker are located inside the compartment filled with SF6 gas. When the arc interruption happens, the arc is cooled down by compressed SF6 from a separate reservoir. After the interruption, SF6 gas is pumped back into the reservoir. This reservoir must be equipped with heating equipment to ensure that the SF6 will not liquefy. However, failures of heating equipment can result in this type being unable to operate as circuit-breakers.
Puffer-Type Sf6 Circuit-Breakers :
Basically this Sf6 circuit breaker’s working principle is to generate compressed gas during the opening process. The moving contacts move the piston and thus compressing the gas in the chamber. As a result, the compressed gas flows along the arc channel and thereby extinguishing the arc. The development of puffer-type SF6 circuit-breakers can be divided into two generations: first and second generations. The principle of arc interruption of both generations is similar but the improvements of the second generation concentrate on the better design, improvement of short-circuit rating, arcing contact lifetime and the material of the nozzle.Since the gas has to be compressed, the puffer-type SF6 circuit-breaker must have a strong operating mechanism.


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