Novel method of error current compensation for Hall-effect-based high-accuracy current transformer

In this paper, a novel scheme for error current compensation of current transformers (CTs) is presented. The method is to apply Hall current transducers (HCTs) based on magnetic force balance to detect and compensate the error current so as to eliminate the error of CT caused by its exciting current. Theoretical analysis and experimental tests clearly illustrate the performance of the proposed scheme. After compensation, the accuracy of the common CT is increased 500 times from 0.5% (5000 ppm) to 0.001% (10 ppm) at the condition of burden Z(b) = 1 Omega, COS phi = 1. A self-calibrating method is adopted for a current transformer with the wind ratio of 1:1.