A 12 kV, 300 MVA synchronous generator is tested at a fieldcurrent of 200 A. The open-circuit voltage was found to be 10 kV and the short-circuit current was 7.5kA. The stator resistance was...

A 12 kV, 300 MVA synchronous generator is tested at a field current of 200 A. The open-circuit

voltage was found to be 10 kV and the short-circuit current was 7.5 kA. The stator resistance was measured at 0.1 ohms per phase.

i) Find the value of the synchronous reactance in per-unit. [ 2 marks ]

ii) The synchronous generator is delivering half rated output at a terminal voltage of 5% below rated voltage and a power factor of 0.7 lagging. Find generator output voltage and current phasors in per-unit. [ 2 marks ]

iii) Under a different load condition, the generator output voltage and current is V = 1.00 pu and

I = 0.75

[ 3 marks ]