Example 6.2
We shall now solve the above problem differently. The Thevenin impedance at the circuit between the terminals A and B of the circuit of Fig. 6.9 is the parallel combination of the impedances j 0.4 and j 0.5148. This is then given as
per unit 

Since voltage at the motor terminals before the fault is 1.0 per unit, the fault current is
per unit 

If we neglect the prefault current flowing through the circuit, then fault current fed by the motor and the generator can be determined using the current divider principle, i.e.,
per unit
per unit 

If, on the other hand, the prefault current is not neglected, then the fault current supplied by the motor and the generator are
per unit
per unit 

