SOLUTION

Airblast circuit breaker:- In this type of circuit breaker, compressed air is used for the arc extinction. Hence it is called a compressed air circuit breaker. Those types of circuit breakers were employed in earlier days in indoor services for voltages ranging from 11 to 1100 kV with breaking capacities up to 25000 MVA. At high voltages, this type of circuit breaker is most suitable. 

In the modern-day, the air blast circuit breaker is also employed in high voltage circuits in the outdoor switchyard. The air blast circuit breakers are preferred for arc furnace duty and traction systems because they are suitable for repeated duty. These type of circuit breakers are finding their best application in systems operating in the range of 132 kV to 400 kV with breaking capacities up to 7000 MVA.

Advantages:-

1. The various advantages of air blast circuit breakers are
2. No fire hazards are possible with this type of circuit breaker.
3. The high-speed operation is achieved.
4. The time for which arc persists is short. Thus the arc gets extinguished early.
5. As arc duration is short and consistent, the amount of heat released is less and the contact points are burnt to a less extent So the life of circuit breaker is increased.
6. The extinguishing medium in this type of circuit breaker is compressed air which is supplied fresh at each operation.
7. The arc energy at each operation is less than that compared with the oil circuit breaker. So air blast circuit breaker is most suitable where frequent operation is required.
8. This type of circuit breaker is almost maintenance-free.
9. It provides the facility of high-speed reclosure.
10. The stability of the system can be well maintained.

Applications

The air blast circuit breakers are preferred for arc furnace duty and traction systems because they are suitable for repeated duty. These type of circuit breakers are finding their best application in systems operating in the range of 132 kV to 400 kV with breaking capacities upto 7000 MVA.