Compensation of Current Transformers

Abstract

In the paper a method for the compensation of current transformer is proposed. The method is based on two main steps: (i) the realization of an equivalent short circuit so that the magnetizing current I₀ is not dependent from the burden resistance; (ii) a circuit generating a compensating voltage Vc which compensate the voltage drop across the longitudinal parameters of the transformer. Since the developed transducer is a non-conventional transformer with the secondary nominal current of 5 A, it is not possible to measure the phase and ratio error with a comparison method. At this aim, a technique for measuring the transformer error by means of a data acquisition system is also proposed in the paper.