Vibroacoustic diagnostics of transformers in a transient state with reduced influence of magnetostriction phenomenon

In the paper a vibroacoustic method of diagnostics of the mechanical state of an active part of a transformer is presented. The analysis is performed on the signal of bank vibrations in a transient stage of work of an unloaded transformer - during the first few seconds after connecting to the power supply. The method is based on SSM algorithm (Spectral Subtraction Method) reducing the ‘disturbing’ impact of magnetostriction phenomenon on the measurement. It was concluded that using, in the process of diagnostics of an active part of a transformer unit, only the vibroacoustic method does not provide certain conclusions. Experimental research proved high usefulness of the presented V-SSM method (Vibroacoustic Spectral Subtraction Method) when accompanied by FRA method (Frequency Response Analysis) in winding defect diagnostics.