Prediction of local temperature rise in power transformer tank by FEM

Abstract

Paper presents experimental and numerical research on tank local overheating. By using an experimental model, phenomena of tank local overheating are investigated without need of expensive experiments on real transformer unit. This first step of research is made with reliable measurements of losses and temperatures in tank on a simple experimental setup. Using commercial numerical tools based on finite element method (FEM) for coupled electromagnetic-thermal calculation, temperatures on experimental model are calculated. Both electromagnetic and thermal model have nonlinear parameters that can have high influence on value of stray losses and cooling conditions. Calculated temperatures are compared to measurement results.In the last part of the paper, measurements of tank temperatures with infrared camera on real three-phase power transformer are presented. 3D nonlinear numerical model of power transformer is created in FEM. Numerical model includes core, windings, LV leads and metal parts. Obtained temperatures are compared to calculation results by FEM and give good agreement.