Phasor Diagram Of Synchronous Generator

In this article, we will discuss one of the easiest methods of making the phasor diagram for a synchronous generator. Now, let's write the various notes for each quantity in a single location, this will help us understand the phasor diagram more clearly. In this phasor diagram, we will use:

Ef, which indicates excitation voltage

Vt indicating terminal voltage

Ia that denotes the chain of the armature

θ that denotes the phase angle between Vt and Ia

ᴪ that denotes the angle between Ef and Ia

δ that denotes the angle between Ef and Vt

which indicates the strength of the reinforcement per phase

To draw the phasor diagram, we will use Vt as a reference. Consider these two important points that are written below:

• We already know that if a machine is working as a synchronous generator, the direction of Ia will be in phase with that of Ef.
• Phasor Ef is always ahead of Vt.

These two points are necessary to make the phasor diagram of the synchronous generator. Given below is the phasor diagram of the synchronous generator:

In this phasor diagram, we trace the direction of Ia in phase with that of Ef, as per point 1 mentioned above. Now we are going to derive an expression for the emf excitation in each case. We have three cases written below:

1. Generating operation with delayed power factor.
2. Generation operation on the unit's power factor.
3. Generation operation on the main power factor.

The following are the phasor diagrams for all operations.

Image Source- Google