Study on electromagnetic force characteristics and vibration noise of shell-type transformers under different inter-turn short circuits

Shell transformers are widely used in power systems and new energy fields owing to their compact structure and high short-circuit resistance. An inter-turn short circuit is a typical fault in operation and can easily cause electromagnetic force distortion, leading to abnormal vibration and noise, which threatens equipment safety and environmental comfort. To study the electromagnetic force, vibration, and noise performance of a shell-type transformer with different inter-turn short-circuit degrees, this study first examines the magnetostrictive and magnetic properties of a silicon steel sheet in a shell-type transformer core and presents the B–H and B–λ curves of a 20QG090 silicon steel sheet. Second, the stress–strain σ–ε curve of the winding is tested and analyzed, and curves at different temperatures are presented. Based on the magnetic characteristics of the silicon steel sheet and the results of the magnetostrictive curve and winding stress–strain curve, the electromagnetic force characteristics and vibration noise of a 50 kVA shell-type transformer were simulated using COMSOL finite element software. In the simulation, the influence of different short-circuit turns in the winding on the transformer’s electromagnetic and vibration noise was considered, providing a theoretical basis and data support for inter-turn short-circuit fault diagnosis, structural optimization design, and noise-reduction measures for shell-type transformers.