Variation of Magnetic Flux on the Occurence of Ferroresonance in a Transformer Using Finite Element Method

Abstract

Ferroresonance is an oscillation in a non- linear circuit containing transformers at light load or no load coupled with a capacitor. The non-linear behav- ior of the core material of the transformer at no load is represented by a nonlinear equation. The capacitive effects of the power network are treated as a capacitor in series with the transformer equivalent circuit. As the system contains a nonlinear equation, it was diffi- cult to analyze the model using the linear method. The finite Element Method is used here for the simulations of ferroresonance. The Finite Element Method allows a field solution to be obtained, even with time-varying fields with non-homogeneous or non-linear fields. This method helps to find out the changes that occur in the magnetic structure of the core under ferroresonance. Supply voltage is taken as the variable parameter. Ca- pacitor and transformer voltages along with the phase plane are analyzed before and after the occurrence of ferroresonance over-voltage. Distribution and change in the magnetic flux during.