Analysis on the magnetic flux leakage distribution in the transformer under different winding deformation and typical working condition

The transformer partial winding deformation, as the precursor of the inter-turn insulation breakdown and total winding mechanic instability, often induces the change of magnetic flux leakage distribution. And monitoring online the magnetic flux leakage characters and diagnosing the transformer partial winding deformation is the novel and good method to prevent the transformer faults in advance, which can make up for the shortcomings of the existing methods. Thus, it is key to explore the magnetic flux leakage distribution law under different winding deformation and working conditions. In the paper, the 35kV power transformer was selected as the research object and its simulation model with different partial radial and axial winding deformation was built. The equivalent method of abnormal operating conditions including DC (Direct current) bias and external short-circuit was determined. Consequently, the change law of magnetic flux leakage characteristics in the transformer was analyzed under the different conditions. The results show the magnetic flux leakage under different winding deformation has a different distribution characteristic, and the information can be used to identify the severity degree and location of the defects. And the character of winding deformation can be distinguished from the disturbances by the feature identification.