Research on Online Simulation System of Complex Faults in UHVDC Transmission

State Grid of China has built a ultra-high voltage AC/DC hybrid power grid. The complex fault of ultra-high voltage dc (UHVDC) has great impact on the security and stability of the power grid, including UHVDC monopole blocking, commutation failure and restart. It is urgent to study a new type of ultra-high voltage dc online simulation analysis system. In this paper, the influence of UHVDC complex faults is studied on safety and stability of State Grid of China with large-scale renewable energy integration, an online simulation system architecture of high voltage dc complex fault is designed, the application scenario of security and stability analysis for different dc faults is presented, the key technologies of dc electromechanical transient model, stability control strategy online modeling and prevention and control decision making are studied.