Thermal Modeling of Electrical Transformers

Thermal modeling of transformer is necessary to ensure the optimal design and cost of manufacture of transformer. Either of the empirical formulae available from the standards and practical measurement techniques used in the industries as an alternative to the formulae will not be able to answer the problem exactly and hence the development of software based thermal modeling techniques that use the advantages of today’s computational power and produce a quicker as well as best solution is the need of the day. A good number of thermal models are available for thermal modeling of transformer, which are based on lumped values of losses. This paper presents a thermal model based on FEM technique and circuit modeling that can calculate the thermal profile across the transformer geometry at any instant, given the input of the loading conditions at that instant. The model has been tested on an industrial transformer and the results obtained are compared with the practical measured data for that transformer.