Question

The secondary leakage reactance of a C.T. ____________

(a) increases its ratio error

(b) decreases its ratio error

(c) has no effect on its ratio error

(d) increases the impedance of the circuit

The question was asked during an online interview.

My question is based upon Design Features of Current Transformers in portion Extension of Instrument Ranges of Electrical Measurements

Answer 1

Correct choice is (a) increases its ratio error

The best I can explain: The windings in a current transformer must be kept close so that the secondary leakage reactance is minimum. Secondary leakage reactance of a C.T. thus increases its ratio error.