On-line demagnetization method for an iron core CT

Abstract

This paper proposes a demagnetization method for iron core current transformers (CT). A dc voltage source is used to charge an inductor, and the discharging effect of the charged inductor is used to demagnetize the remanent flux of the iron core CT. To verify the performance of the proposed method, the different core characteristics, level of remanent flux, and possible errors in all elements and measured core characteristics are analyzed with EMTP-RV simulator.