Oct 03, 2020 - 02:16 AM
Since synchronous machine has variable reactance, calculation at any instant requires a formula
involving time as one of the variables. Usually for the sake of simplicity, the reactance is considered
fixed over the time interval for which the fault current is calculated .
Please refer the below formula
Here reactance, voltage is in p.u and t in seconds
In this case if you need to calculate the final steady state short curcuit currrent, You can use Isc=E/Xd and multiply with your acutal rated current to get the actual short circuit current.