The Influence of the Window Width on FRA Assessment with Numerical Indices

Frequency response analysis is a method used in transformer diagnostics for the detection of mechanical faults or short-circuits windings. The interpretation test results often performed with application numerical indices. However, usually these indices are whole frequency range recorded data, returning single number. Such an approach inaccurate and may lead to mistakes interpretation. An alternative quality assessment based on estimation local values index moving window method. In this paper, authors analyse influence width input data four measured deformations introduced into winding also 10 MVA under industrial conditions. For first unit various widths extents deformation, while case second real differences between curves being analysed. On basis it was found that choice significantly influences rules elements number selection differ