Buckling Strength Analysis of Transformer Windings Based on Electromagnetic Thermal Structural Coupling Method

Abstract

Winding buckling is a common and complex type of transformer failure. The commonly used method for calculating the buckling strength of transformer windings does not take into account the factors of plastic deformation and thermal effect. Therefore, in the stability analysis of the winding, the stress process of the default winding is ideal elastic. Even if some transformer windings meet the design standards, there is still the risk of instability in reality. A method for analyzing the buckling strength of transformer windings based on electromagnetic thermal structure coupling method is presented in this paper. Through a transformer example, the fault current, leakage magnetic field, and electromagnetic force of transformer are analyzed by field circuit coupling method. A model of the relationship between temperature and yield strength is established, and the temperature rise and ultimate instability load of transformer windings are analyzed by finite element method and experiment. The influence of plastic deformation and thermal effect on the ultimate instability load is considered. The results show that plastic deformation and temperature rise should not be ignored in the buckling strength analysis of transformer windings. The research results have certain reference value for transformer design.