FE-based Modeling of Single Phase Distribution Transformers With Internal Winding Short Circuit Faults

In this paper, an accurate circuit model is proposed for single phase distribution transformers with internal winding faults. The model is developed based on flux linkages. An equivalent excitation current variable i_m is defined. The variation of psi(i_m) with the winding currents is used to describe the nonlinear magnetization, which are obtained from FE solutions. With such a method, the circuit model has the same accuracy as the FE model and is obtainable with manageable FE calculations. Two types of internal winding faults are modeled, the turn to ground short circuit fault and the turn to turn short circuit fault. In both cases, the flux linkage profile, the Simulink implementation of the FE-based fault model, and its verification and application examples are presented