Research On Modeling And Simulation Of Transformer Windings Under VFTO Based On Transfer Function

In this paper,the order-reduced technology of transformer windings modeling in GIS and circuit simulation are researched.Firstly, the voltage transfer functions deduced from the S parameters are fitted with rational functions by vector fitting . Secondly, the rational voltage transfer functions are order-reduced by modified Routh approximation. Lastly, the resultant voltage transfer functions are synthesized by lumped elements. The simulation results from the circuit are in good agreement with the measured and calculated ones. This shows that the method is correct and this circuit model can reflect the voltage under VFTO in the transformer windings correctly.