Power transformer top-oil temperature model based on thermal–electric analogy theory

This paper presents a thermal–electric analogous thermal model of an oil-immersed power transformer. The model is established to calculate the top-oil temperature in the form of simple equivalent circuit based on the fundamental heat transfer theory. The presented model takes into account application of the lumped capacitance, nonlinear thermal resistances, and oil viscosity, whereas Levenberg–Marquardt Method is used as a search method to determine the thermal model parameters. For the OFAN and OFAF power transformers, a lot of experimental data and curves show the proposed model in this paper can yield better results than IEEE thermal model and be used widely in the power transformer fault prediction field. Copyright © 2007 John Wiley & Sons, Ltd.