1. What is switchgear? Discuss the components of switchgear.
2. What is power system protection? Briefly discuss the importance of power system protection.
Write the factors must be considered in the selection of bus layout & switching arrangement for
a substation
3. Define circuit breaker and fuse. Explain how the tripping of circuit breaker works. What is a
tripping circuit?
4. Explain the function of primary and backup protection.
5. What is meant by the zone of protection in power system? Discuss the necessity of overlapping
in protective zones in a power system.
6. Differentiate between fuse and MCB. Mention the reason for short-time rating of circuit breakers.
7. Classify fuse. Also, differentiate between HRC fuse and Circuit breaker. What is HRC fuse? How
does it operate?
8. What is TRV, RRRV, Restriking voltage? What is electric arc? How is it interrupted? Define current
chopping.
9. What are isolators and earthing switch? How do they operate in coordination with circuit breaker
for disconnecting a circuit?
10. What is making and breaking capacity of circuit breaker? Discuss their relationship.
11. What is auto reclosure? Discuss its suitability for overhead and underground systems.
12. Define Instrument transformer. What is burden of a CT? How is it specified?
13. What is meant by saturation in CT? How can its effect be minimized?
14. Discuss how a PT works.
15. Define Lightning Arrester. Describe how it works.
16. Discuss the different types of lightning arresters. Explain the operation of SiC and ZnO arresters.
17. Define Relay. Discuss the fundamental requirements of protective relaying.
18. Classify Relay. What are the possible actuating quantities for different relaying scheme?
19. Discuss the Electromagnetic Attraction Type Relays.
20. Define Impedance relay, Directional relay, IDMT Overcurrent relay, distance relay, and impedance
relay. Mention the advantage of using distance relays over overcurrent relay in transmission line.
21. Using figure explain how induction type directional power relay works
22. Using figure explain how electromagnetic attraction type relay works.
23. Define busbar. Discuss different types of busbar arrangement with proper figure. Write down the
advantage and disadvantage of different bus scheme.
24. Compare between oil circuit breaker and Vacuum circuit breaker.
25. Discuss the operation of Vacuum circuit breaker and Axial blast air circuit breaker.
26. Discuss the means of protecting alternator using Merz-Price protection scheme.
27. Discuss the common type of fault occurring in a transformer and suggest the major protection
scheme for a transformer. Using figure, discuss how Buchholz relay operate.
28. Using figure, discuss in detail how sulfur hexafluoride circuit breaker works.
Math- related to fuse, PSM and TMS, CT, Circuit breaker.
