Question

The angle \( \delta \) in the swing equation of a synchronous generator is the:

• A. angle between stator voltage and current
• B. angular displacement of the rotor with respect to the stator
• C. angular displacement of the stator MMF with respect to a synchronously rotating axis
• D. angular displacement of an axis fixed to the rotor with respect to a synchronously rotating axis

Hint:

Swing angle \( \delta \) tells how far the rotor lags or leads the ideal synchronous position.

Answer 1

The Correct Option is D

Step 1: What is the swing equation?
It is a second-order differential equation used to describe the rotor dynamics in response to disturbances in power systems.
Step 2: Meaning of \( \delta \)
The angle \( \delta \) represents the position of the rotor relative to the synchronously rotating reference frame.
Step 3: Significance
It helps determine the stability of the synchronous machine by comparing actual rotor position vs ideal synchronous position.
Conclusion:
So, it is the angular displacement of a rotor-fixed axis w.r.t a synchronously rotating axis → Option (4).