Question

A 3-phase, 1.2 MVA, Y-connected, 6.6 KV, 6-poles, 60 HZ, synchronous generator has a synchronous reactance of 30W and negligible resistance. The generator is connected to an infinite bus at 6.6 KV and 60 Hz.

a)Determine the excitation voltage (Ea) when the machine is delivering rated power at o.8 PF lagging.

b)The field excitation current is increased by 10% without changing the power input from the prime mover. Find the stator current (Ia), the power factor and the reactive power supplied by the machine.

c)With the field excitation current kept constant as in part (a), the input power from the prime mover is increased slowly. Determine the value of stator current, power factor and reactive power at the steady state limit? What is the steady state limit?

Answer #1

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