How do you increase the reactive power of an alternator?
If you like to increase the MVAr or reactive power then increase the excitation current in the excitation system. And do decrease to do the reverse. The excitation current to rotor creates magnetic flux. So by controlling the strength of magnetic flux we are controlling the reactive power.
How active power and reactive power output from an alternator is controlled?
As known, the active power control is the control of torque produced by the machine and the reactive power control is the control of flux. The stator active and reactive power of doubly-fed wound rotor induction generator is controlled by regulating the current and voltage of the rotor windings.
How can the reactive power delivered by a synchronous generator be increased?
Detailed Solution. The reactive power delivered by a synchronous generator can be controlled by changing its excitation. In that way real power does not change but the power factor changes.
Why active power remains constant when field current is increased?
The power of motor will vary only when the torque of the load shaft varied. So the field current has zero effect of speed of rotation of a shaft, as the load connected with shaft of motor is constant so active power provided by the motor will also remain constant.
How does reactive power vary with power factor?
Reactive power is related to the power factor Voltage and current are in phase; the active power in this case is equal to the apparent power. Due to the presence of inductive and/or capacitive reactive power the apparent power increases and the power factor becomes less than 1.
What are the advantage of placing field winding in rotor in an alternator?
The field winding of an alternator is placed on the rotor and is connected to DC supply through two slip rings. It is easier to insulate stationary winding for high voltages for which the alternators are usually designed.