Inter disc fault location in transformer windings using SFRA

Winding faults are one of the major causes for failures in Power transformer. Detection and localization of winding faults is indispensable for prevention of damages as the outage may lead to costly, time consuming repair and replacement of the equipment. This contribution is aimed at locating inter disc faults using the sweep frequency responses of the winding. A method for determining the location of faults using the Fault Factor characteristics has been developed using a 22 kV continuous disc winding. The proposed methodology employing the hyperbolic model predicts the exact location of the fault by considering only two known reference values, for different percentage of faults. The algorithm is validated on interleaved and layer winding of different ratings. Using circuit simulation package, verification is done on a high voltage winding of a 25MVA 230/6.6kV transformer, with the low frequency equivalent circuit model of the transformer winding.