Breakers on either side of IS-Limiter

[NickParker]

Is it usual to provide circuit breaker on either side of the IS-Limiter? Why is it so? Why cant be single breaker used as bus tie (with IS-limiter)?

On Bus A - there are 2 Generator Incomers
On Bus B - there are 2 Generator Incomers
Bus tie - With IS - limiter (On either side of IS-Limiter, there is a breaker)

 

[RRaghunath]

Is limiter is like a fuse that acts fast to open the circuit at the time of fault and is so fast that it is current limiting. Fuse that clears a fault needs to be replaced. In a similar way, Is limiter has a cartridge that needs to be replaced every time it operates to control the fault level on either of the bus bars.
This means the tie feeder will be down for some time. Having two breakers one on either side allows us to keep both the busbars live while the Tie is down pending replacement of cartridge in Is limiter.
It is not necessary to have breakers on either side of Is limiter, only one can be breaker and the other can be Disconnector if that saves cost.