Evaluation of current transformer performance in the presence of remnant flux and harmonics

Abstract

This paper studies and evaluates the effect of current transformer (CT) distortion parameters on its performance using various secondary current calculation methods according to IEC 44–1 & 44–6 like: magnitude (ratio) error, peak instantaneous error, phase error and composite error. These parameters include: multiple short circuit level (Isc/IR), secondary burden value & type, DC component (X/R ratio & fault inception angle), remanent factor (Kr) and both external & internal harmonics.