Affiliations: [a] School of Control and Mechanical Engineering, Tianjin Chengjian University, Tianjin, China
Correspondence:
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Corresponding author: Wenqi Ge, School of Control and Mechanical Engineering, Tianjin Chengjian University, Tianjin 300380, China. E-mail: [email protected]
Abstract: Due to the vulnerability of power transformer windings to overcurrent impact during operation, significant electromagnetic forces are generated, posing potential hazards of failure. Therefore, it is crucial to conduct an analysis of the electromagnetic forces under overcurrent conditions. In this study, a three-phase power transformer model is established, with specific attention given to the refinement of winding modeling. Utilizing Maxwell software, the simulation and analysis of the leakage field of transformer windings, axial distribution of electromagnetic forces, and their transient processes over time are performed under short-circuit currents and magnetizing inrush currents during no-load closure. The simulation results reveal that both types of overcurrent result in axial electromagnetic forces on the windings that are larger at the ends and smaller in the middle. However, for magnetizing inrush currents, higher harmonic proportions are observed, and an electromagnetic force equivalent to that induced by short-circuit currents can be generated when the magnitude of the magnetizing inrush current reaches approximately 30% of the short-circuit current magnitude. These findings provide a significant reference and foundation for further examination of the cumulative effects and stability of windings under overcurrent impacts in transformers.
Keywords: Axial electromagnetic force, inrush current short-circuit current, transformer
