Question

Explain Squirrel Cage Induction Generator (SCIG) and also draw a diagram.

Answer 1

Diagram of Squirrel Cage Induction Generator (SCIG):

Explanation (Operation):-
 In this system multistage gearbox is used to obtain constant speed irrespective of
wind speed.
 SCIG require reactive excitation power.
 The SCIG takes the reactive excitation power from a capacitor bank, connected
across the stator terminals of the IG  Rotor of SCIG is rotated at more than synchronous speed(i.e. low negative slip) to
generate emf (to export power)with the help of wind power.
 Generated voltage is 690 V AC. So it must be step up to 33 KV to connect to power
grid.

Answer 2

Explanation (Operation):-
 In this system gearbox is used to increase the speed of high speed shaft as per design.
 IG require reactive power for excitation.
 Rotor of SCIG is rotated at more than synchronous speed (i.e. low negative slip) in
the variable range to generate emf with the help of wind power.
 It uses AC-DC-AC power converter (Rectifier, Inverter & Filter) to convert variable
frequency, variable voltage output of the generator into the fixed frequency, fixed
voltage output required for grid.