Some applications of the coupled field-circuit method

The method presented in this paper is based on the incomplete coupling of circuit and field models for the simulation of electromagnetic fields in a transformer, which provides power to the converter system during different modes of operation and failures. With this method the coefficient matrix remains symmetric and banded and circuit and field equations are solved simultaneously. The presented model allows the analysis of the currents, voltages and the flux density distribution in several converter sets. Two examples are presented here. The first analysed model was a converter transformer applied for railways. The second example concerns a specially prepared three-limb, two-winding model transformer supplying a three phase 6D bridge.