Current transformers Voltage transformers - Electrical Engineering (MCQ) questions and answers

1)   What is the residual voltage in VT?

a. Vector sum of three line to line voltages
b. Vector sum of three line to earth voltage
c. Vector sum of three phase voltage
d. None of these
Answer  Explanation 

ANSWER: Vector sum of three line to earth voltage

Explanation:
No explanation is available for this question!


2)   What is the accuracy class of residually connected VT?

a. 5.00 or 10.00
b. 6.00 or 12.00
c. 4.00 or 8.00
d. 10.00 or 20.00
Answer  Explanation 

ANSWER: 5.00 or 10.00

Explanation:
No explanation is available for this question!


3)   What is the application of capacitor voltage transformers?

a. Line voltmeters
b. Protective relays
c. High speed distance protection
d. Both (a) and (b)
e. All of these
Answer  Explanation 

ANSWER: Both (a) and (b)

Explanation:
No explanation is available for this question!


4)   Which method of connection is preferred for VTs?

a. V – V connection
b. Star – star connection
c. Star - open delta
d. All of these
e. None of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!


5)   What are the types of voltage transformers?

a. Electromagnetic potential transformers
b. Capacitor potential transformers
c. Inductor and resistor potential transformers
d. Only (a) and (b)
e. All of these
Answer  Explanation 

ANSWER: Only (a) and (b)

Explanation:
No explanation is available for this question!


6)   Which among these is the essential part for a CT?

a. Insulation over the core by tape
b. Support porcelain or epoxy insulator
c. Synthetic resin or oil insulation
d. All of these
e. None of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!


7)   Which among these is not a type test performed on the current transformers?

a. Overvoltage inter turn tests
b. Short time current tests
c. Temperature rise tests
d. Error measurement
Answer  Explanation 

ANSWER: Overvoltage inter turn tests

Explanation:
No explanation is available for this question!


8)   What is over current factor?

a. The specified limits of ratio error and phase angle error.
b. The ratio of rated short time current to rated primary current.
c. A specification by the manufacturer at which CT performs with the specified accuracy.
d. The phase angle between primary current vector and reversed secondary current vector.
Answer  Explanation 

ANSWER: The ratio of rated short time current to rated primary current.

Explanation:
No explanation is available for this question!


9)   What is rated burden in current transformers?

a. The specified limits of ratio error and phase angle error.
b. The ratio of rated short time current to rated primary current.
c. A specification by the manufacturer at which CT performs with the specified accuracy.
d. The phase angle between primary current vector and reversed secondary current vector.
Answer  Explanation 

ANSWER: A specification by the manufacturer at which CT performs with the specified accuracy.

Explanation:
No explanation is available for this question!


10)   What is the use of current transformers?

a. Stepping up AC current
b. Measuring and protection
c. Stepping down AC current
d. Both (b) and (c)
e. All of these
Answer  Explanation 

ANSWER: Both (b) and (c)

Explanation:
No explanation is available for this question!