Abstract:The shortcircuit impedances are important technical parameters for a fourwinding induction filtering transformer (FWIFT), which not only affects the steadystate operation and shortcircuit current calculation, but also involves the effect of induction filtering. In this paper, an induction decoupling method is proposed to establish the voltage equation of four winding induction filter transformer. Then, based on the shortcircuit method, the shortcircuit impedance characteristics of four winding induction filter transformer and influences of filter impedance on the shortcircuit impedances are analyzed on the basis of the threephase shortcircuit method. Finally, a shortcircuit experiment is included to verify the correctness of the theory and calculation method. It is shown that the equivalent impedance of the filter winding is zero, which meets the constraints of the inductive filter. Meanwhile, the impedance parameters of the filter have no influences on the shortcircuit impedance.