Research on on-line diagnosis of transformer winding deformation

This paper presents an on-line method to diagnose transformer winding deformation by Frequency Response Analysis.(FRA). In this study, FRA were performed by digital simulation using MULTISIM based on several kinds of winding deformation, such as short-circuit between one-phase coils, short-circuit between two-phase coils and short-circuit between one-phase coils and ground The simulated differences of different winding deformation were discussed in detail. We find that the resonant points of frequency response curve at different frequency represent different winding deformation. It also showed the resonant points of frequency response of each winding deformation changes with the exact deformation position. The load characteristic of the power system and the power line state are possible to influence the characteristics of the frequency response spectra, a high frequency-impedance is necessary to degrade the influence. So, according to the characteristics of the frequency response spectra, the winding deformation can be detected accurately while it occurs.