A study of hot-spot localization in distribution transformers

Ageing of transformer winding insulation is strongly temperature dependent and the problem of temperature rise in transformer during operation has been investigated. However, accurate temperature determination in transformer winding is still a challenge and the location of hottest-spot temperature in transformer also requires further studies. In this study, COMSOL Multiphysics simulation software was used to simulate an oil-filled distribution transformer, taken into account the temperature dependence of cooling fluid properties. The temperature rise in the transformer was investigated by solving the heat equations along with the equations for free convection flow. The proposed approach is able to predict the hottest-spot location as well as the hottest-spot temperature.