Study of Natural Convection Heat Transfer Characteristics and Correlation Equation on The Outer Surface of Power Transformer Bushings

As the most important component of power transformers, bushings are often used to connect power transformers and power system busbars. The temperature directly affects the bushings internal insulation aging state, the internal overheating will directly lead to thermal breakdown of insulation, triggering major accidents. This paper builds a two-dimensional model of the power transformer bushing based on CFD simulation software, and performs meshing and simulation calculations on the model. By establishing transformer bushing skirt models with different structures, the relevant structural variables that affect the natural convection heat dissipation coefficient of the skirt surface, such as characteristic length, Nusselt number, etc., are analyzed. Finally, the relationship between the geometric parameters of the skirt and the convective heat transfer coefficient was obtained through data fitting, thereby achieving the accurate calculation of the convective heat transfer coefficient on the skirt surface. The proposal of this correlation is of great significance for the optimal design of the transformer bushing.