A Z-transform model of transformers for the study of electromagnetic transients in power systems

A Z-transform model, which combines transformer frequency-dependent short-circuit impedances with gain functions, has been developed. It sets up a relationship between transient voltages and currents on both sides of a transformer winding pair. The model can be used to calculate impulse responses of the transformers with open-circuit secondary winding as well as those connected to other networks. It could be incorporated into EMT (electromagnetic transient) programs for calculating the EMTs in power systems in which the distributed characteristics of transformer windings are to be considered.<
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