Study on the Damage to Transformer Windings Under Multiple Short-Circuit Faults

Power transformer winding damage caused by short-circuit faults is a long-term issue of concern. To investigate the winding deformation process under multiple short-circuit impacts, a real full-scale 40 MVA/110 kV transformer was subjected to short-circuit (SC) faults. Furthermore, an electromagnetic-mechanical coupled method was presented. Using the 3-D finite-element method, the transformer winding deformation development process was simulated. The numerical simulation results and direct experimental evidence indicate that the failed spacers are the mechanical weakness points in the winding, which can cause unbalanced stress and overstress to be distributed to the adjacent copper disks during a short-circuit fault.