Seismic Failure Analysis of Electrical Connection Structure of Grid-Side Bushing of ± 800 kV Converter Transformer

The electrical connection structure (ECS) is a key component of the current-carrying loop in the converter transformer-bushing system. To investigate the response and failure characteristics of the ECS under earthquake excitation, this study established a refined finite element model of a grid-side bushing containing the ECS of surface-to-surface compression type and seismic failure analysis was performed on the electrical contact surface during earthquake events. A three-level classification of contact stress levels for nodes was proposed based on the inverse relationship between contact stress and contact resistance. During the most unfavorable moment of the electrical contact surface, the uneven distribution of contact stress exhibits a distinct pattern. Under seismic loading of 0.4 g, the area proportion where contact stress is reduced by 1/3 compared to the normal condition is halved. The influence of the conductive rod on structural performance failure should be carefully considered in the seismic design of the ECS in the grid-side bushing. Measures should be taken to improve the electrical contact performance of the ECS under seismic loading.