Propagation mechanisms of pressure waves in transformer insulating oil under arc discharges

To address the risk of pressure surges and explosions caused by internal short-circuit arcs in oil-immersed transformers, this paper first derives formulas for arc discharge energy and bubble pressure. A three-dimensional simulation model of an SFSZ-240000/220 transformer is then established. Pressure source parameters are defined, and the propagation of pressure waves within the insulating oil is analyzed through simulations to clarify the influence of oil properties on wave propagation. Multiple parameters of the simulation model are adjusted, and virtual probes are placed at specific locations on the tank wall. By varying the initial arc position, the number of arcs, and the density of the insulating oil, the system is analyzed from two perspectives: the transient pressure distribution across the tank wall and the resulting mechanical deformation. Based on these findings, suggestions for improving the structural design of the transformer tank are proposed. These results provide theoretical support for the explosion-proof structural design of transformer tanks and the prediction of fault-induced pressure.