Practical Experience in Using a Topological Model of a Core-Type Three-Phase Transformer—No-Load and Inrush Conditions

This paper describes an experience in transformer modeling based on open-circuit test data obtained for a wide range of terminal voltages on the low-voltage side and inrush current measurements on the high-voltage side carried out for different residual fluxes of a 300-kVA transformer. The core-type transformer model is based on a dynamic hysteresis model, which is employed individually in the legs and yokes. We start with the case where the core geometry and winding turns are known when fitting the model. The method proposed is then extended to the case where only the nameplate data and the measured no-load losses and currents are available. For this latter case, an optimization model fitting is developed.