Eddy Current Loss Effect in Foil Winding of Transformer Based on Magneto-Fluid-Thermal Simulation

The foil winding temperature distribution is crucial to the life of power transformer since local heating can accelerate aging of insulation materials. However, based on the traditional 3-D electromagnetic model and the principle of heat transfer, the non-uniform losses and temperature distribution of foil windings are difficult to estimate because of complex magnetic leakage flux. In this paper, the magneto-fluid-thermal coupling model has been established to calculate the temperature rise and predict the potential hotspots of a simplified dry-type power transformer rated at 2500 kVA. Moreover, the influence of insulation barrier is considered to reshape the air-flow path and to affect the radiative effect between the high-voltage and low-voltage windings. Experimental temperature rises are measured with infrared thermography to verify the simulation results, which achieved reasonable hotspot predictions and provide the theoretical method for transformer designers.