If you think you have a good understanding of Current Transformer Fundamentals, challenge yourself and take the quiz.
Best of Luck.!!
Question 1 of 20
Q.1 A current transformer is used to:
Step up current
Step down current
None of the above
Question 2 of 20
Q.2 The most common application of current transformer is:
It is used for protection purpose
It is used for measuring purpose
Both
Question 3 of 20
Q.3 In CT, the current entering in the dot at the primary side of the winding:
Must exit from the dot at the secondary side
Must enter from the dot at the secondary side
Question 4 of 20
Q.4 In a transformer, current is:
Directly proportional to number of turns
Inversely proportional to number of turns
Question 5 of 20
Q.5 Considering primary current is kept constant, if it is required to have a lower current value at secondary side:
Number of turns at primary is increased
Number of turns at secondary is increased
Number of turns at primary is decreased
Both (a) & (b)
Both (b) & (c)
Question 6 of 20
Q.6 Calculate Primary current (Iₚ), when Iₛ = 2 Amp and Nₛ : Nₚ = 120 : 1.
120
240
60
Question 7 of 20
Q.7 The line current flowing to the ground in a Delta connected CT circuit is always:
Ila + Ilb + Ilc
Ila - Ilb - Ilc
Zero
-Ila - Ilb + Ilc
Question 8 of 20
Q.8 Keeping primary current and number of turns at primary constant if we double the number of turns at secondary, the secondary current becomes:
double
half
4 times
Remains same
Question 9 of 20
Q.9 In a current transformer, burden is:
Load connected at secondary side of transformer
Core impedance
Leakage impedance
Question 10 of 20
Q.10 During normal operation, a CT secondary can never be left:
Short
Open
Question 11 of 20
Q.11 What is the relation of secondary voltage (Vs) and burden voltage (Vb) in a current transformer?
Vs = Vb
Vs < Vb
Vs > Vb
Question 12 of 20
Q.12 The main requirement for a protection type CT is that it must have:
a high saturation point
a high accuracy class
a large turn ratio
Question 13 of 20
Q.13 The main requirement for a metering type CT is that it must have:
a high accuracy
Question 14 of 20
Q.14 In additive polarity, primary and secondary have a phase shift of
0°
180°
120°
Question 15 of 20
Q.15 In subtractive polarity, primary and secondary have a phase shift of
Question 16 of 20
Q.16 What will be the effect on CT, if its secondary terminal is ungrounded?
Secondary end current increases
Secondary end voltage rises
No effects
Question 17 of 20
Q.17 Which of the following representation shows a protection class C.T:
0.2 S
5P20
0.1
Question 18 of 20
Q.18 Knee point voltage in C.T is defined as voltage beyond which:
10 % increase in secondary voltage will cause excitation current to increase by 50%
10 % increase in primary voltage will cause excitation current to increase by 50%
10 % increase in secondary voltage will cause secondary current to increase by 50%
Question 19 of 20
Q.19 In order to check the polarity of a CT, which test can be performed?
AC test
DC test
Current method
Phase angle method
All of the above
Question 20 of 20
Q.20 The magnetization impedance (Ze) is a ___________ quantity and is directly proportional to the ________________.
Linear, secondary current
Non-linear, secondary voltage
Linear, secondary voltage
Non-linear, secondary current