An Efficient Method to Compute Transfer Function of a Transformer From its Equivalent Circuit

Abstract

The dynamics of an electrical network can completely be described from the knowledge of its poles and zeros. Computation of poles and zeros of the transfer function (TF) of a transformer winding, represented as a coupled ladder network, involves solution of a large-sized equivalent circuit. This paper presents a novel solution based on state space analysis approach. It is shown, how the linearly transformed state space formulation, together with algebraic manipulations, can become useful. In the proposed formulation, symbolic variables (i.e., Laplace variable, s) are suitably manipulated, so as to render computations purely numerical. With this feature, there is practically no limit on the size of networks and topologies (including resistances to model losses) that can be represented. So, virtually any number of windings of a transformer can be considered, permitting a comprehensive analysis of winding behavior and its interactions, that was until now severely limited, by the simplifying assumptions imposed by existing methods.