Question

The voltage regulation of a transformer at full-load 0.8 p.f leading is -2%. Its voltage regulation at full load 0.8 p.f lagging _____________

(a) will be positive

(b) will be negative

(c) may be positive

(d) may be negative

The question was posed to me in a job interview.

This is a very interesting question from Autotransformers in section Transformers of Electrical Machines

Answer 1

Correct answer is (a) will be positive

The best explanation: The leading p.f. has negative v.r. and lagging p.f. has major portion of positive voltage regulation.