Network modelling of traction substation transformers for studying unbalance effects

The paper presents network mathematical models of traction substation transformers for simulation of the unbalance effects, due to railway demands, on the power supply system. The admittance models consider winding connections and phase-angle displacement between primary and secondary voltage. The proposed models are presented for the single-phase, V- and Scott connections of transformers used in, among other places, high-speed railway stations.