7.5 If the source impedance at a 13.2 kV distribution substation bus is (0.5 +j1.5) per phase, compute the RMS and maximum peak instantaneous value of the fault current, for a balanced three-phase fault. For the system (X/R) ratio of 3.0, the asymmetrical factor is 1.9495 and the time of peak is 7.1 ms (see Problem 7.4). Comment on the withstanding peak current capability to which all substation clectrical equipment need to be designed