Application of statistical tools in power transformer FRA results interpretation: Transformer winding diagnosis based on frequency response analysis

In this paper, Frequency Response Analysis simulations of a three-phase transformer were conducted via Finite Element Analysis and Matlab software. The contribution of this work is the authenticity of the equivalent Simulink model in eliminating 50 Hz frequency, leaving the purely pulse signals. The results were further verified statistically using F-Test and T-Test statistical techniques. F-test and T-test are viewed among others as two major adopted statistical tools that give the exact and accurate condition of the transformer windings based on the concept of objective winding asymmetry. It was proven that two sets of FRA data when tested with F-test and T-test match as long as the windings are in good condition. They prove otherwise when any of the phases is faulty.