Correct Answer - Option 1 : 60
Concept:
Speed of synchronous generator in rpm is given by
\({N_s} = \frac{{120f}}{P}\;\)
Where,
f = supply frequency in Hz
P = Number of poles
Calculation:
Given-
Ns = 100 r/min = 100 rpm,
f = 50 Hz
When hydraulic turbine is connected to synchronous generator, then both are running at same speed
∴ \(100 = \frac{{120 \times 50}}{P}\)
P = 60