Evaluation of Thermal Models used to Estimate the Hot-Spot Temperature in Distribution Transformers

Abstract

This paper presents an evaluation of the main transformers thermal models considering the number of input data required and the output data reliability of each model. Also, a brief analysis of transformer thermal behaviour based on the hot-spot temperature is shown. Then, an experimental validation of the thermal models performed in two oil-immersed distribution transformers is described, simulating a load profile in specific periods of time. Finally, the experimental results are compared with data resulting from the implementation of the models in numerical analysis software in order to establish the parametric differences and precision of each model showing that the most optimal performance corresponds to the model of differential equations of the International Electrotechnical Commission.