Development of steady state model for transformer internal faults

This paper presents a novel method to model the steady state behaviour of internal faults in transformers. Transformer with turn-to-ground fault can be represented by an impedance matrix. Modified Nodal Analysis (MNA) is employed to calculate the steady state values of node voltages and branch currents under faulted condition. The computations are implemented using a MATLAB program. Similar conditions were simulated using PSCAD/EMTDC and the results were compared. The steady state quantities obtained from this method can be used for designing the protective scheme for transformer internal faults.