Dynamic deformation analysis of power transformer windings considering the influence of temperature on elasticity characteristics of winding materials under short circuit fault

The elastic characteristics of transformer winding materials have an important influence on its deformation due to short-circuit (SC) fault. This paper presents an electromagnetic-thermal-fluid-mechanical coupling analysis method for dynamic deformation calculation of power transformer windings under SC fault, considering the influence of temperature on modulus of elasticity of winding materials. The dependence of modulus of elasticity of spacer and copper conductor on temperature in transformer windings are tested by dynamic thermal mechanical analyzer. The transient dynamic response of windings deformation including mechanical stress and displacements, as well as temperature distribution, for an oil-immersed-type 110 kV power transformer due to SC are obtained using the proposed method. The maximum stress and displacement achieved by the proposed method is greater than that calculated neglecting the temperature dependence of elasticity of modulus of winding materials. The upper part of the winding are more susceptible to damage due to SC impact.