Study on Cumulative Characteristics of Transformer Windings Based on Finite Element Simulation

The study on cumulative characteristics of transformer windings is of great significance to improve the short-circuit withstand ability of power transformers. Current research on the cumulative characteristics of windings is nascent, with the impact of simulation modeling methods—including multiple short-circuit conditions—on these characteristics yet to be established. Therefore, the cumulative characteristics of windings are studied based on finite element simulation in this work. Firstly, we examine the simplified method of simulating multiple short-circuit impacts. Furthermore, we utilize a multi-physics coupling model to evaluate the effect of short-circuit current loading on the cumulative characteristics. The results demonstrate that the short circuit current under intermittent loading, considering the residual stress, is more consistent with the engineering practice than that under continuous loading. Our study of intermittent loading reveals that with an increase in short-circuit impacts, the equivalent stress under load diminishes gradually, suggesting a hardening phenomenon. Therefore, the winding shows stronger bending resistance with increased strain when the copper wire reaches the plastic stage. In addition, when the winding enters the hardening stage, the cumulative increase of the displacement and stress borne by the winding are reduced.