Calculation of Transformer Short-Circuit Impedance Based on Energy Method

Transformer short-circuit impedance is an important parameter to check the performance of transformer products, which determines the size of the short-circuit current and the size of the internal electric force of the transformer when the system is short-circuit. The size of the short-circuit impedance affects the stability of the transformer winding. During the short-circuit process of the transformer, the winding must bear the effect of the electric force under different short-circuit conditions, which causes the transformer winding to produce elastic and plastic deformation. The short-circuit impedance also determines the voltage change of the transformer under load, that is, it will affect the voltage fluctuation during the operation of the power grid. In this paper, an on-load voltage regulating power transformer is used as a prototype for three-dimensional finite element calculation in Maxwell eddy current field, and the short-circuit impedance is calculated by the energy method.