The Lean Design of High Altitude Converter Valve for Sub-address Cascade UHV DC Project

The cascade UHV DC project realizes the decentralized arrangement of the converter station, and realizes the cross-region access of multiple types of renewable energy bases. This paper analyzes the influence factors of high altitude on the design of converter valve, including the influence of cosmic radiation on the failure rate of thyristor, the influence of high altitude on the clear distance and crawl distance of converter valve, and checks the influence of high altitude on the heat dissipation of converter valve and the influence on the surface field strength. Lean design converter valve according to the cosmic radiation factor, creep margin factor, small gap voltage margin factor to correct the single valve thyristor series number, lean design of converter valve insulation type test, the single valve insulation test will be carried out under the condition of not lower than the altitude of the site, MVU and valve base insulation test will be carried out under the existing plain area test conditions.