The Sweep Frequency Response Analyzer is used for power transformer with voltage grade of 6kV and above and other transformers with special purpose. The power transformer is inevitably vulnerable to impulse of various fault short-circuit current or physical collision in the process of operation and transportation and the transformer windings may lose stability under the powerful electro-dynamic force exerted by such short-circuit current, which could result in permanent deformations such as local distortion, swell or dislocation and will severely affect safe operation of the transformer. Deformation of transformer windings is measured with frequency response analysis method according to national standard DL/T911-2016/IEC60076-18 for electric power industry, i.e. detect amplitude-frequency response characteristic of each transformer winding and make vertical or horizontal comparison of the detection result to judge possible deformation of the transformer winding based on change of amplitude-frequency response characteristics.