Q.1 (5 Marks) A 3-phase, 6-pole, doubly-fed induction generator has a rating of 800 kW. The
stator is connected to a 60 Hz line and the rotor winding is connected to a variable-frequency
converter that produces a frequency of 24 Hz. The machine is operating at super-synchronous
speed and the wind turbine develops 500 hp. The wind turbine is connected to the rotor shaft by
way of a speed-raising gear box. Given:
Friction losses Pv=11 kW; Rotor I2R losses Pjr=3 kW; Stator I2R losses Pjs=12 kW;
Stator iron losses Pf=7 kW; Converter losses Pc=2 kW
Find:
a. Mechanical power delivered to the rotor.
b. Power developed through the air gap.
c. Power through the stator.