Error analysis and accuracy improvement strategy of transformer winding short circuit electromagnetic force calculation model

Power transformers are susceptible to winding deformation, instability, and insulation damage under short-circuit conditions, posing a significant threat to grid stability. Accurate and efficient calculation of the winding's short-circuit electromagnetic forces is crucial for understanding the mechanisms of winding deformation, material degradation, and multi-field coupling behavior. This study focuses on a three-phase core transformer, constructing various two-dimensional models (e.g., plane, open-core column, and closed-core column) and three-dimensional models. It analyzes the impact of mesh refinement, mesh consistency, and equivalent boundary conditions on the calculation results. The results show that mesh consistency is the primary factor influencing the calculation accuracy of the 2D model, while equivalent boundary conditions have minimal impact on the calculation of key electromagnetic forces under consistent mesh conditions. Furthermore, the electromagnetic force calculations for the open-core model are relatively small, while those for the closed-core model are larger. A weighted average of these results can effectively limit the error to within 5%, approximating the results of the 3D model, while significantly reducing computational resource consumption. This study provides a valuable reference for the efficient and accurate calculation of transformer short-circuit electromagnetic forces.