Electromagnetic Force Analysis of Transformer on the Ferroresonance due to Consecutive 3–Phase Short–Circuit Faults Using Finite Element Method (FEM)

In this paper, Finite Element Method (FEM) is used to study the ferroresonance phenomenon from the perspective of the electromagnetic forces introduced on the transformer windings. In order to simulate this phenomenon, a consecutive 3–phase short–circuit fault is considered to be on the primary side at a relatively distant from the transformer. Then, due to the capacitance of the line, between the error point and transformer, the single–phase short–circuit faults are generated, one–by–one. Because of the switching, for isolation feeder from the fault point, the ferroresonance appears in power system. Then, voltages and currents of the primary and secondary windings will be changed. The effect of current changes on the forces that transformer coils withstand, when the ferroresonance happens, is an interesting topic to this paper. With modeling of the transformer and feeder switching in the FLUX 12.2 software, the ferroresonance condition is simulated. Due to the dependence of the ferroresonance on the non-linearity of the magnetic characteristic of the transformer core, Jiles–Atherton vector hysteresis model is used to modeling the core hysteresis loops for enhancement the results accurate.