What is synchronous generator?
Definition: The synchronous generator or alternator is an electrical machine that converts the mechanical power from a prime mover into an AC electrical power at a particular voltage and frequency. The synchronous motor always runs at a constant speed called synchronous speed.
What are the applications of synchronous generator?
Synchronous generators are commonly used for variable speed wind turbine applications, due to their low rotational synchronous speeds that produce the voltage at grid frequency. Synchronous generators can be an appropriate selection for variable speed operation of wind turbines [166,167].
Why is it called synchronous generator?
A synchronous generator is called “synchronous” because the waveform of the generated voltage is synchronized with the rotation of the generator. Each peak of the sinusoidal waveform corresponds to a physical position of the rotor. The magnetic field of the rotor is supplied by direct current or permanent magnets.
How do synchronous generators work?
In a synchronous generator, a DC current is applied to the rotor winding producing a rotor magnetic field. The rotor is then turned by external means producing a rotating magnetic field, which induces a 3-phase voltage within the stator winding. The rotor of a synchronous machine is a large electromagnet.
What is the difference between asynchronous and synchronous generator?
A synchronous generator is called “synchronous” because the waveform of the generated voltage is synchronized with the rotation of the generator. An asynchronous generator is essentially the same machine as an asynchronous or induction motor. …
Why do synchronous generators need excitation?
Synchronous motor excitation refers to the DC supply given to rotor which is used to produce the required magnetic flux. CASE 2: If the field current is not sufficient enough to produce the required air gap flux as demanded by V, additional magnetizing current or lagging reactive VA is drawn from the AC source.
Which is better synchronous or asynchronous generator?
Synchronous generators (large ones at least) are more efficient than asynchronous generators. Synchronous generators can more easily accommodate load power factor variations. Synchronous generators can be started by supplying the rotor field excitation from a battery.
How do you sync a generator?
For two generators to be synchronized they must have equal number of phase; same phase angle, same voltage, frequency and identical voltage sine curve ( waveform ). This means the RYB connection point of bus bar; should be connected to RYB terminals of incoming generator and not RBY.
What is the process of generator synchronization?
Generator synchronization is the process of matching parameters such as voltage, frequency, phase angle, phase sequence, and waveform of alternator (generator) or other source with a healthy or running power system. This is done before the generator is reconnected to the power system.
What happens if you sync a generator with a power system?
If generator synchronization with a power system is done incorrectly or poorly executed, there is the potential for: Generator & prime mover damage due to mechanical stress caused by rapid accelerator/deceleration need to bring the rotating masses in synch. Damage to the generator and step-up transformer windows due to the high currents
When do you need to synchronize alternators in a generator?
The need for synchronization arrives, particularly when two or more alternators are working together to supply the power to the load. This is because electrical loads are not constant and they vary with time (depending on the load) and hence it is necessary to interconnect two or more alternators operating in parallel to supply larger loads.
How is the terminal voltage of a synchronous generator controlled?
• A synchronous generator operating at a leading power factor often has a negative voltage regulation. Normally, a constant terminal voltage supplied by a generator is desired. Since the armature reactance cannot be controlled, an obvious approach to adjust the terminal voltage is by controlling the internal generated voltage EA = K.