Seismic Performance and Reinforcement Strategies for ±600 kV Suspended Converter Valves - Part2: Strengthening Approaches

Suspended converter valves exhibit high seismic vulnerability. To mitigate the seismic response of suspended converter valve, two seismic strengthening strategies are proposed: vertical seismic bracing and diagonal seismic bracing. The analysis reveals the diagonal seismic bracing scheme demonstrates superior performance in controlling seismic displacement and structural stress due to its enhanced lateral stiffness. With the diagonal seismic bracing scheme, both displacement and stress safety margins meet seismic design requirements. Compared to the unreinforced converter valve, the displacement is reduced by 53% or more, and the maximum seismic stress on the suspended insulator is reduced by 44% or more. Therefore, it is recommended to adopt the diagonal seismic bracing damping technology for the ±600 kV suspended converter valve in high seismic intensity zones, as it can effectively and economically enhance the seismic resilience of high voltage direct current projects.