Dear Mr. Ally ;
Certainly you can.
Please find below another important points :
– The ” Loop Impedance “ for a fault at any point in the network should be calculated from the source to this point, that means : MV, Tr, and all cables till the point of fault.
– If the used Earthing System is different than ” TN-C “, in this case, we should calculate ” Isc1min & If ” specialy if the ” N & PE ” have different sections that means ” Isc1min ≠ If “.
– If you use ” IT system ” : it's better to define first the ” Fault's Loop ” then calculate the Loop Impedance, as there's many method to realize the ” IT “.
I's at your disposal for any inquiry.