A current transformer is a type of instrumentation transformer that steps down current in power systems to safe levels that can be processed via relays and measurement devices/equipment. Current transformers can be found in generation stations and switching stations.
Given below are the most important Current Transformer MCQ Questions
Current Transformers are used for
Current Transformers are used for:
- Measurement purposes
- Instrumentation
- Protection
- All of the above
Correct answer: 4. All of the above
A current transformer plays the measurement, instrumentation as well as protection roles in power systems.
Secondary winding rating of Current Transformer
Current transformers usually have a secondary winding rating of:
- 5 A
- 20 A
- 50 A
- 100 A
Correct answer: 1. 5 A
Secondary circuit of Current transformer should never become
Secondary circuit of Current transformer should never become:
- Open circuited
- Short circuited
- Any of these
Correct answer: 1. Open circuited
Explanation: Complete explanation for CT secondary closure
Selector switches used for CT should be of which type
Selector switches used for CT should be of which type:
- Make before break
- DPDT
- Low impedance
- None of these
Correct answer: 1. Make before break
Explanation: The selector switches used for CT should be of Make before break type so that CT never becomes open-circuited.
Primary Terminals of CT are marked using letters
Primary Terminals of CT are marked using letters:
- X1 and X2
- H1 and H2
- P1 and Q1
- P1 and U1
Correct answer: 2. H1 and H2
Secondary Terminals of CT are marked using letters
Secondary Terminals of CT are marked using letters:
- X1 and X2
- H1 and H2
- P1 and Q1
- P1 and U1
Correct answer: 1. X1 and X2
Current transformer with rated secondary current of 5 A and Rating factor 4.0 RF can hold secondary current of
Current transformer with rated secondary current of 5 A and Rating factor 4.0 RF can hold secondary current of:
- 4 A
- 5 A
- 10 A
- 20 A
Correct answer: 4. 20 A
Rating factor of CT indicates maximum current that can flow through a CT without exceeding the thermal capability of its windings
Cast Resin type Current Transformer is recommended for
Cast Resin type Current Transformer is recommended for:
- Indoor use
- Outdoor use
Correct answer: 2. Outdoor use
Generally cast resin type transformers are recommended for outdoor use.
Turns ratio of current transformers
Current transformers (CTs) have turns ratios:
- Greater than one
- Lesser than one
- Equal to one
- None of the above
Correct answer: 2. Lesser than one
Current transformers have turns ratios less than one.
What happens if the secondary of a current transformer is open-circuited
What happens if the secondary of a current transformer is open-circuited:
- A decrement in an overall efficiency of the metering circuit occurs
- Dangerously high voltages can develop
- Wrong values of output
- Nothing happens
Correct answer: 2. Dangerously high voltages can develop
If the secondary of a current transformer is open-circuited dangerously high voltages can develop. So the secondary of a current transformer should never be open circuited.
So that was all about the Current Transformer MCQ Questions.
Similar to Current Transformer MCQ:
- The pick-up current of a 100/5 transformer having a current setting of 200% will be
- The current transformers that are used to protect power transformer with star-delta connection against the earth and phase faults should be connected in which configuration
- The differential protection of delta/delta power transformers is achieved using which of the following connection of the current transformer
- The Zero-sequence current can flow from a line to the transformer bank if the windings are in