Magnetic Saturation Effect of the Iron Core in Current Transformers Under Lightning Flow

Abstract

A current transformer (CT) is a type of sensor that consists of a combination of electric and magnetic circuits, and it measures large ac currents. When a large amount of current flows into the primary winding, the alternating magnetic flux in the iron core induces an electromotive force in the secondary winding. The characteristics of a CT are determined by the iron core design because the iron core is saturated above a certain magnetic flux density. In particular, when a large current, such as a current surge, is input into a CT, the iron core becomes saturated and the induced electromotive force in the secondary winding fluctuates severely. Under these conditions, the CT no longer functions as a sensor. In this study, the characteristics of the secondary winding were investigated using the timedifference finite element method when a current surge was provided as an input. The CT was modeled as a twodimensional analysis object using constraints, and the saturation characteristics of the iron core were evaluated using the Newton-Rhapson method. The results of the calculation were compared with the experimental data. The results of this study will prove useful in the designs of the iron core and the windings of CTs.

Analysis of the feasibility of adding a grid-connected hybrid photovoltaic system to reduce electrical load

“…Determining the ideal operating conditions for the power system will offer input data for error calculations and stability assessments. The Newton Raphson approach is used to complete the power flow design [26], [27]. The method has the advantage of solving power flow problems by solving a set of nonlinear equations to calculate the magnitude of the voltage and the phase angle of the voltage at each bus [28], [29].…”