Seismic performance and restraint system of suspended 800 kV thyristor valve

Suspended thyristor valves are widely used in ultra high voltage (UHV) direct current transmission projects all over the world nowadays. However, the seismic performance of the 800 kV thyristor valve, which has longer hangers, larger air clearance requirement and is heavier than its lower voltage counterparts, has not been fully investigated. This study firstly established a finite element (FE) model of an 800 kV thyristor valve and its corresponding hall building to evaluate the seismic response of the valve. Subsequently, a restraint system consisting of rods, springs and viscous dampers was introduced to reduce the seismic response of the valve. Parametric analysis was carried out on a simplified model to determine the optimal design parameters of the restraint system. The FE model of the restrained valve, making use of the optimal parameters, was investigated. The results show that the system with the optimal parameters can effectively reduce the horizontal displacement of the valve. It is proposed to apply the restraint system to the valves, or other types of suspended equipment, to reduce the horizontal displacement and accordingly increase the seismic resiliency of this types of suspended equipment.