Design and Implementation of Dielectric Windows for Detection of Radial Deformation of HV Transformer Winding Using Radar Imaging

The synthetic aperture radar (SAR) imaging method has been recently proposed for online radial deformation detection of high voltage transformer windings. In this method, electromagnetic waves should be transmitted toward the transformer windings through an antenna. The antenna should be moved along the height of the transformer. Since electromagnetic waves cannot penetrate the metal tank, a window is required on the body of the transformer tank to transmit waves toward the winding. The proper design of such a window and investigation of SAR imaging methods with the existence of it, is necessary to make the previous SAR imaging studies applicable to the transformer winding. Therefore, in order to study the design and implementation of a dielectric window, a prototype of a tank with a dielectric window is built considering electrical and mechanical constraints. The experimental results show the feasibility of applying the SAR imaging for localisation of radial deformation with the existence of a dielectric window in real transformers.