Is the reactive power absorbed or delivered by the synchronous motor then the synchronous motor is operating at a lagging power factor?
Explanation: At normal excitation, there is no reactive power flow as the power factor is unity. At under-excitation, it works at a lagging power factor and hence it absorbs the reactive power.
Does synchronous machine generate reactive power?
Synchronous generators can generate or absorb reactive power depending on the excitation. When overexcited they supply reactive power, and when underexcited they absorb reactive power.
How synchronous motor can be used for reactive power compensation?
The added current flowing to supply reactive power creates additional losses in the power system. In an industrial plant, synchronous motors can be used to supply some of the reactive power required by induction motors. This improves the plant power factor and reduces the reactive current required from the grid.
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.
What is reactive power synchronous motor?
Synchronous motors provide mechanical work and in contrast to all other major motor types can also provide capacitive reactive power to the system. The amount and kind of reactive power delivered by the motor is being determined by the excitation current in the rotor.
When the synchronous motor is called a synchronous condenser?
When the motor is operated at no load with over-excitation, it takes a current that leads the voltage by nearly 90 degrees. Thus, it behaves like a capacitor and under such operating conditions, the synchronous motor is called a synchronous capacitor.
What happens when synchronous generator is over excited?
An over excited synchronous generator generates reactive power as its excitation is increased (over excited ) means the magnetic field strength of the stator winding of the synchronous generator is now increased more by increase in DC excitation , so in such a case more flux will induce in stator winding and when this …
What determines when a synchronous motor is at normal excitation?
Synchronous motor excitation refers to the DC supply given to rotor which is used to produce the required magnetic flux. The field current, which causes this unity power factor is called normal excitation or normal field current.
How does a synchronous motor correct power factor?
A Synchronous Motor can be made to operate at unity and leading power factor by just increasing its excitation voltage i.e. by increasing the field current. This advantage of Synchronous Motor is used to improve the power factor.