Switchgear & Protection | Third year | Diploma in Electrical and Electronics Engineering | SBTE Bihar

 1. List any eight essential features of effective protective system.

2. Define TSM and PSM in relays.

3. Name internal and external causes of system over-voltages.

4. Define: i) Arcing time ii) Recovery time iii) Arcing voltage iv) Rate of rise of restriking voltage

5. Difference between Equipment Earthing and Neutral Earthing:

6.  Whether MCB is operated for earth fault? Give reason

7. List the difficulties experienced in differential relay in alternator protection. How are they overcome?

8. Explain arcing phenomenon in circuit breaker.

9. Distinguish between circuit breaker and isolator.

10. Draw a neat labeled diagram of Merz Price protection scheme for an alternator.

11. With neat sketch explain Thyrite type Lighting Arrestor

12. Explain time graded over current protection for ring main system of busbar.

13. Explain what is single phasing of 3ϕ I.M? Draw a neat circuit diagram of single phase preventer.

14. Explain differential protection for busbar with diagram.

15. Explain construction and working of HRC fuse with diagram.

16. State methods for arc extinction and explain working of any one method with neat circuit diagram.

17. With the help of neat sketch, explain principle of operation and working of induction type over current relay.

18. With neat sketch, explain watt-hr-meter structure of induction type relay.

19. Draw neat sketch of induction type reverse power relay and explain its working.

20. Compare electro mechanical relay and static relay.

21. Draw figure for restricted earth fault protection scheme for transformer.

22. Explain why the secondary of a CT should not be open circuited?

23. Explain how negative sequence current are set up in an alternator? Draw protective scheme for same.

24. Explain over heating protection scheme of 3 phase transformer.

25. Explain with neat sketch the operation of attracted armature type relay. State two advantages.