This paper explores dry-type power transformer losses, focusing on stray losses. Using 3D frequency-domain nonlinear electromagnetic finite element analysis, these losses are investigated, particularly concerning load conditions and structural components. A method to measure stray losses is proposed by comparing simulation and experimental results. Findings reveal that stray losses during no-load tests are minimally impacted by structural components, but under short-circuit conditions, stray losses closely match rated conditions. It is suggested that stray losses induced by structural components are influenced by the current. Further analysis indicates that stray losses are directly proportional to current squared. Furthermore, simulation results are compared with factory test reports, which suggest that stray losses from structural components contribute to short-circuit losses. Valuable insights into power transformer loss characteristics are provided by this research, contributing to performance enhancement and efficiency improvement.

Finite element method,Stray loss,Structural components,Transformer