Diagnosis of power transformer magnetic core and windings failure by sweep frequency response analysis

Abstract

This paper presents a method of power transformer diagnosis by sweep frequency response analysis (SFRA). SFRA is an effective tool to diagnose power transformer mechanical failure in magnetic core and windings by detecting windings distortion and magnetic core displacement. Diagnosis includes failure analysis and assessment via Bode diagrams. A case study of power transformer magnetic core and windings diagnosis has been implemented for an auxiliary power transformer of 180 kVA, nominal voltage 22/0,4 kV. Diagnosis result by SFRA showed the same result with the opening checking of power transformer in practice, while it was not detected with traditional diagnosis methods. SFRA should be investigated and developed more strongly for power transformer diagnosis.