The prospective(available) short-circuit current is a current that would flow in the circuit if the switch, the limitation device and the load impedance are replaced by links of negligible impedance without any other change in the circuit.
只是模拟一个短路时候的电流,因为测试电路后面是有负载的,所以不会出现真的1500A的情况。(即使出现了也没关系,保护器会先动作的。)
关于可用的短路电流的概念和具体算法,可以去看一下IEC60909,国标是GB/T 15544。