The two-stage current transformer

James R. Craighead: There are in addition to those outlined in this paper, several other methods of making phase angle correction in current transformers. The simplest is the use of a non-inductive shunt placed across the primary winding or across the secondary winding, which subtracts a certain amount of current either from the primary or the secondary side of the transformer. This current is in a phase position which is such that it tends to restore the remainder of the secondary current to the phase position of the primary current, and by so doing can diminish to some extent the usual leading (or positive) phase angle of the current transformer. Inductive reactance may be substituted for the non-inductive shunt where the phase angle is negative.