DC current sensor using switching-mode excited in-situ current transformer

Abstract

DC current component in the power grid may cause gross measurement errors and lead to overheating of power transformers. We have previously developed method how to measure DC current using fluxgate effect in existing current transformers. In this paper we show that using ferroresonance the power consumption of such device can be drastically reduced. The microprocessor can both control the H-bridge excitation unit and perform signal processing, avoiding the need of external instruments.