Order-reduced method of voltage transfer function of transformer windings based on vector fitting

Firstly, voltage transfer functions are derived from short-circuit admittance parameters which are calculated from the distributed parameters or measured parameters of transformer windings. Secondly, voltage transfer functions are fitted with rational functions by vector fitting and the rational transfer functions are order-reduced by optimal Pade approximation. Lastly, resultant voltage transfer functions are synthesized with passive elements and ideal transformers. An actual transformer windings as mathematical model is used to validate the proposed algorithm, simulation results confirm the feasibility and validity of recommended methodology.