Radji-Kermani - International Steel Industrial Engineering Co.
jamali - Iran University of Science and Technology, Iran

The dc component of the fault current is the main cause of the current transformer (CT) saturation. The exciting current of the saturated CT depending on the core flux increases and distorts the secondary current, so that the corrupted current waveform may cause the maloperation of he protective relays. This paper presents a new, fast, simple -and effective algorithm to compensate the above problem by, adding the calculated exciting current to the measured secondary current and its hardware implementation for this propose.

Digital protection, Hysteresis, Current transformer(CT), Saturation, EMITP