A Practical Guide to Calculating the Expansion Coefficient of a Transformer Tank for Rupture Analysis Using the Finite Element Method

This paper investigates pressure calculations based on IEEE Std C57.156™-2016 to evaluate the structural integrity of a transformer tank. Key parameters were identified, and the pressure equation was solved to obtain static pressure values. These values are then set to finite element analysis using a nonlinear material model to assess the transformer's tank strength. The tank expansion coefficient, influencing the results significantly, was calculated through pressure-dependent volume changes. Among the methods tested, combining Ansys DesignModeler and Ansys SpaceClaim proved most efficient for determining the internal volume of the deformed geometry. Strength analysis revealed that the highest stress occurs in the tank and cover welding line, with stresses nearing the tensile ultimate strength of the materials. The findings suggest that further design enhancements are necessary to improve the transformer's durability.