Improved arc containment of a bushing turret of UHV AC Transformers under a high-energy internal arcing fault

In this paper, a transient fluid-structure interaction model with an equivalent arc pressure source is first established to investigate the shock response of L-type turrets. Based on failure analysis, reinforcement measures are then applied to the bolted connection parts of the turrets, and the hand-hole covers are replaced with rupture discs for pressure relief. All design schemes are compared under the working condition of a 15 MJ arcing fault. The study finds that shock waves inside the turrets form localized gradient pressure distributions, and the equipment exhibits coupled displacement and rotational motion. Pressure concentration at the top and rotational behavior of the turrets will exacerbate the mechanical stress degradation of the bolts. The results demonstrate that structural reinforcement can effectively reduce bolt strain, and pressure relief structures have a remarkable effect on improving arc protection performance. This study provides a feasible design scheme for the arcing fault protection of bushing turrets.