Transformer winding deformation is one of transformer faults of the main types, which threatens the security of power grid. Hence, impedance-based frequency response analysis is proposed to diagnose transformer winding deformation. Impedance frequency characteristics of transformer winding in low and intermediate frequency were further studied. Based on the wiring of frequency response analysis, relevant data of voltage and current is measured and processed to make impedance frequency curves. Transformer winding deformation is diagnosed through the comparison among the difference of response curves. The simulation model of transformer winding deformation was established, in which parameter values of different types of element were changed to simulated winding deformation. The simulation results showed that the proposed method can response winding deformation obviously, which validated the effectivity of the frequency response impedance method.
