Assume from Main Breaker rated 1250A ,
TR Sizing is 630kVA 24 kV /240-416 VAC , Transformer short circuit impedance around 4% (Z) so Maximum Short circuit level ( Infinite bus) not more than 35kA(rms) ,So The incoming circuit breakers, which are proposed with Air Circuit Breaker (ACB) under model of Masterpact from Schneider Electric, can be complied and confirmed in accordance with technical information that shown in the drawing.