Experimental Study On Transformer Winding Fault Diagnosis Based On Vibration Frequency Response Analysis

Vibration frequency response analysis is the method to diagnose the condition of power transformer by collecting and analyzing vibration signals of the transformer surface.The non-invasive and non-electrical connection detection method is a powerful supplement for the traditional methods based on electrical measurement.In this paper,the vibration frequency response analysis is adopted as a research method and transformer windings are taken as research objects,their vibration characteristics under normal and unhealthy status are studied by theoretical analysis combined with experimental demonstration.The main research contents are as in the following:Transformer winding deformation and vibration mechanism analysis: The transformer winding and core vibration law and related factors are analyzed,in order to study the vibration analysis method to detect transformer winding fault provides the theoretical basis.The study on the modeling of the mechanical dynamic characteristics of transformer windings: The finite element analysis model of the transformer windings is established by using large-scale finite element analysis software.The vibration response characteristics of the transformer windings are calculated and analyzed,and its correlation with various influencing factors is analyzed.In addition,the typical transformer winding faults are artificial.And the vibration response characteristics of transformer winding are analyzed.Transformer winding vibration modal test research: The transformer winding modal test platform is built.Respectively,the vibration modes of transformer windings under normal and unhealthy status are tested and analyzed.Finally,the experimental study of the solid transformer: The physical transformer is taken as the research object and the transformer windings under normal and unhealthy status are detected.It is concluded that the vibration frequency response curve of transformer winding is closely related to the change of transformer winding state,and the winding vibration frequency sweep test has good repeatability.When the transformer windings are loosened and deformed,the frequency response curve of the winding will change obviously.The frequency of the winding will change with the peak value of the frequency response,and its degree of variation will depend on the winding fault.The vibration frequency response analysis is more sensitive than the traditional frequency response method in the test such as the decrease of winding preload,the falling off of spacer,the amplitude and axial slight deformation.