Because the traditional calculation method of transformer temperature rise is not suitable for the design of fluid-immersed power transformer with hybrid insulation system

this paper built a finite element model of thermal-fluid coupled field for power transformer based on the heat transfer theory and fluid dynamics.The thermodynamic parameter nonlinearity of transformer oil and the effects of bearings and fiber containers in winding construction on heat radiation were considered in this model.Moreover

unit discretization was conducted according to different winding forms.The temperature and flow distributions at different spots in transformer were achieved by the thermal-fluid coupled method

and the results show excellent agreement with experimental ones.The insulation material of transformer was also improved according to computation and measurement results.At last

a method to reduce temperature rise of thermal wallis proposed by expanding the height difference between exit and inlet of radiator.