Application of Frequency Response Analysis Method in the Detection of Winding Deformation Faults in Transformers with Balanced Coils

The stable operation of power transformers ensures the security and reliability of power networks. Winding deformation of transformers caused by short current rush accounts for a large proportion of transformer faults. The frequency response analysis method (FRA) is comparatively widely used in the transformer winding deformation detection. But at the same time, this method is easily influenced by external factors such as detection conditions and wiring methods to lead a misdiagnosis. Based on the analysis and judgment of the FRA test data of a 220kV transformer with balanced coils, this paper proposes that it is a reasonable and feasible connection method to short the two ends of the balanced winding without grounding. It can effectively avoid the influence on the test results of the incorrect connections of the balanced winding in the future.