Important Questions of Protection of Alternators and Transformers:
1. Discuss the important faults on an alternator.
2. Explain with a neat diagram the application of Merz-Price circulating current principle for the protection of alternator.
3. Describe with a neat diagram the balanced earth protection for small-size generators.
4. How will you protect an alternator from turn-to-turn fault on the same phase winding ?
5. What factors cause difficulty in applying circulating current principle to a power transformer 7
6. Describe the construction and working of a Buchholz relay.
7. Describe the Merz-Price circulating current system for the protection of transformers.
8. Write short notes on the following :
(i) Earth-fault protection for alternator
(ii) Combined leakage and overload protection for transformers
(iii) Earth-fault protection for transformers
9. What is the difference between an earth relay and over-current relay ?
10. How does grounding affect relay application ?
11. Why is overload protection not necessary for alternators ?
12. Can relays be used to protect an alternator against
(i) one-phase open circuits (ii) unbalanced loading (iii) motoring (iv) loss of synchronism ?
13. How many faults develop in a power transformer ?