A 10 MV A, 13.8 kV, 50 Hz synchronous generator yields the following test data:
OC test I_{f} = 842 A at rated voltage
SC test I_{f} = 226 A at rated armature current
(a) Calculate its pu adjusted synchronous reactance OC test revealed that the armature resistance per phase is 0.75 \Omega .
(b) The generator is operating at power output of 8.75 MW, 0.9 pf lagging. Calculate
(i) its field current and reactive power output
(ii) the rotor power angle and reactive power output if the field current is adjusted to 842 A while the net shaft power supplied by the prime mover remains constant