A novel methodology for transformer winding defects diagnosis based on its measured frequency response signal impedance morphology interpretation

Abstract

This article proposes the characteristics study of the key parameters of power transformer winding (viz. the equivalent capacitance and the equivalent inductance) extracted from the frequency response analysis (FRA) of the winding. However, the FRA curve of the winding can be divided into three frequency ranges (low, medium, and high), where; the low and the high frequency response (LFR and HFR) ranges represent the inductive and capacitive effects of the winding respectively, which can establish best analysing and interpreting tool of the winding response behaviour to diagnose their failures. Furthermore, real axial deformations were carried out on a winding constructed for this study. In addition, the variation of the equivalent inductance and capacitance obtained from the impedance curve in the LFR and HFR ranges were analysed to locate and evaluate the faulty states with the reference state of the winding. Consequently, the proposed method provides a tool for locating and assessing the internal faults severity in power transformer windings.