ELECTRICAL TESTING & COMMISSIONING INTERVIEW
QUESTIONS
1.
C.T – MOS for Testing?
2.
What is CT Knee point voltage? What is the purpose of doing
Knee point test?
3.
Explain about knee point curve using plot?
4. How can you do
polarity test in CT?
5. Explain about IR,
Polarity, Winding resistance with diagram?
6. CT & VT
Magnetizing current testing method
7. V.T – MOS for
Testing?
8. What is the purpose
of doing magnetizing current test in VT?
9. Operating Principle
of Transformer?
10. What is meant by
Magnetic flux?
11. What do you mean by % Impedance?
12. How to calculate % Impedance?
13. What is the value of IR while testing Transformer at site?
14. What is value of tolerance in short circuit impedance?
15. What is the test
procedure to test magnetic balance in transformer?
16. What are tests to carry out in oil?
17. How transformer
differential stability will be carried out?
18. What is the
difference between no load current and magnetizing current in transformer?
19. What is the procedure
for doing Zero sequence Impedance test?
20. a. What is trip time
/ Closing time of circuit breaker
b. Why tripping time is lesser than
closing time?
21. Draw and explain IDMT characteristics?
22. What are the curves
in Relays?
23. Relays time
calculation formula.
24. Explain the operation
of Directional over current relay with diagram?
25. What is the formula
for relay timing test ( 2times)
26. Explain TCS
(pre-closed & post-closed) circuit with diagram.
27. Backup Relay –Method
of Testing
28. How can you check
synchronizing check
29. Inter trip logics-
Operations
30. Explain about line
protection differential scheme?
31. a. Explain how load
transfer to be done for double bus bar scheme.
b. During load transfer, If there is bus
fault, bus coupler CB will trip (or) not.
32. What is the initial
charging current and final charging current for 1320AH battery of DC scheme?
33. How do you check Synchronizing Scheme?
34. How much distance between spark gap contacts?
