Analysis of Transformer Winding Deformation and Its Locations With High Probability of Occurrence.

Power transformer, as a crucial equipment for power transmission, frequently suffers winding deformation defects, owing to the impact of huge external short-circuit current in actual operation. To resist the rapid deterioration of the defects, online monitoring for winding states is imperative, depending on a thorough understanding of the deformation defects. Unfortunately, there are not much related research on the deformation form and location, as two key objects online diagnosed. In this paper, we concentrate on the analysis of winding deformation and investigation of its high-probability location to deeply understand the winding deformation. For the form of the deformation, a three-dimensional finite element model of the transformer is established to obtain the form and extent of the short-circuit impact force, and a buckling model of the low-voltage winding is designed to analyze the mechanism and form of winding deformation under the impact of huge force induced by short-circuit current. For the location of the deformation, the three-dimensional simulation models are established to analyze the force characteristics of different winding structures in three locations (the conductor transposition area, the area with imbalanced amp-turns and the area with uneven circumferential distribution of force). Then we clarify the possibility of winding deformation in these areas, defined as high-probability locations. Finally, the analyzed results are found to be highly consistent with the actual winding deformation, demonstrating the correctness of the research methods and conclusions. Next stage, the results will provide effective theoretical support for online diagnosis of winding deformation and optimal design of winding structure.