Symmetrical Components Interview Questions:

Following are the below Symmetrical Components Interview Questions and Important Questions which is very useful for interviews and exams

1. Discuss the symmetrical component theory for solving unsymmetrical fault. Derive necessary equations to convert:

• Phase quantities into symmetrical components.
• Symmetrical components into phase quantities.

2. Explain how an unsymmetrical system of 3-phase currents can be resolved into 3 symmetrical component systems.

3. What do you understand by symmetrical components of unbalanced phasors ? Deduce the expressions for symmetrical components.

4. How 3-phase unbalanced phasors are transformed into their symmetrical components ? Discuss.

5. Explain what is the difference between symmetrical components of positive, negative and zero phase sequence.

6. How are the zero phase sequence components of the line currents related to the current in the neutral wire of a 3-phase, 4-wire circuit ?

7. Discuss the principle of symmetrical components. Derive equations to convert phase quantities into symmetrical components.

8. Explain why does the line current of a 3-phase, 3-wire circuit has no zero phase sequence component.

9. Explain the symmetrical component theory. Derive the phase currents in terms of the sequence currents and vice versa.

10. Show that in the delta-connected system, the zero phase sequence voltage is absent in the line voltages.

11. Show that the current through the neutral wire is equal three times zero sequence current.

12. Derive an expression for total complex power in a 3-phase system in terms of symmetrical components of voltages and currents.

13. Derive expression for 3-Φ system in terms of symmetrical components.

14. Find sequence impedances of transmission line’s of a power system carrying unbalanced currents.

15.  Prove that for the transmission line’s zero sequence impedance is much larger than the positive sequence impedance. Also discuss the effect of mutual inductances.

16. Find sequence impedances and draw sequence networks of a synchronous machine.

17. Draw a general circuit, which can be used to determine the zero sequence network of a two winding transformer. Draw the zero sequence network of : (i) Star-Star transformer with star point grounded, (ii) Delta-Delta transformer.

18. Discuss sequence impedances of transformers. Also draw the transformer connection and their equivalent sequence networks.

19. Draw the zero sequence networks of transformer banks.

20. What do you understand by sequence networks ? What is their importance in unsymmetrical fault calculations ?