A flux-linkage model for transformers is presented which can be used for studying the behaviour of transformers under overfluxing conditions. In this lumped parameter approach, all the flux fringing to tank and clamping structures is combined into one parameter: air flux. Thus, air flux is taken as a parameter for studying core saturation as an indirect method. A simple modification to account for saturation in the limb portion is suggested here. This may be achieved by representing the flux between the core outer diameter and the winding inner diameter with an extra path parallel to the limb. In addition, study of the inrush current for the transformer is taken as test case to check the extension of the model. The variation of excitation current with overvoltage and the respective harmonic contents have been reported. The results are presented and discussed.
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