(A) Star/star connections
(B) Delta/delta connections
(C) Star/delta connections
(D) Delta/star connections
Answer: (B) Delta/delta connections
Explanation:
Merz-price differential protection scheme:
Merz-price differential protection is nothing but a percentage differential protection.
It works under the principle of the circulating current scheme.
Merz-price differential protection is used to protect the transformer from internal short circuits, Internal ground faults, and inter-turn short circuits.
The CTs connection in the Merz-price protection:
CTs are connected to every phase of the system.
In order to nullify the phase shift of the Power transformer (PT), The Current transformers (CT) connected in a reverse configuration.
Configuration of PT | Configuration of CTs on primary and secondary of PT respectively |
|---|---|
Y – Y | ∆ - ∆ |
Y - ∆ | ∆ - Y |
∆ - Y | Y - ∆ |
∆ - ∆ | Y - Y |
1. Under over excitation synchronous phase modifier works as
2. The neutral of the power system may be connected to earth
3. The time to open the circuit breaker contact is called as
4. A 100 Ah capacity battery should deliver a current of 10 A for approximately _____ hrs.
5. For 400KV line, The Spacing Between phase conductor is around
6. Shunt capacitors in a sub-station
7. An alternator is said to be over excited when it is operating at
8. In case of transformer Buchholz relay is used to protect from
9. Series capacitors are used to
10. Disadvantage of low power factor is
11. The colour of neutral three core flexible cable is
12. The location of ground faults in underground cables can be found by
13. Fault location in an HV cable is done by
15. Which of the following is not a valid advantage of bundle conductor?
16. Star-star power transformer is protected by current transformer having
17. The surge resistance of cables is
18. Skin effect is only noticeable at _______ frequencies.
19. When transmission voltage is increased, the line losses are
More E-Books
For More Transformer MCQs (Set of 400 Most Asked MCQs)