An Indirect Measurement Approach of a Uniform Transformer Winding Inductances Using Frequency Response Analysis Data: An Analytical Approach

This article proposes an innovative analytical method that estimates winding inductances directly from measurable frequency response analysis (FRA) data. The method constructs a polynomial function based on the inverse‐square sum of short‐circuit natural frequencies and equivalent inductance, incorporating a coupling factor that captures the extent of mutual interaction between discs. Unlike earlier numerical and optimisation‐based methods that typically involve a large number of inductance parameters, the proposed approach yields a physically meaningful real positive solution for the coupling factor. The approach offers a practical analytical solution for indirectly measuring the self‐ and mutual inductances of uniform windings, involving the measurement of relevant winding parameters—such as equivalent inductance, short‐circuit natural frequencies and series and shunt capacitances—using frequency response impedance data. The method then estimates self‐ and mutual inductances for uniform windings by solving a generalised polynomial developed for an N ‐section model, enabling the derivation of all windings' inductances. Experimental validation on isolated transformer windings demonstrated strong agreement between measured and estimated FRA curves, with root mean square error (RMSE) values below . These results confirm that the method offers a practical, traceable and accurate measurement‐based solution for inductance estimation, with potential applications in transformer condition assessment and fault diagnosis.