Overvoltage Mechanism Analysis and Suppression Strategies of VSC-Based HVDC Stations

As renewable energy continues to evolve, long-distance transmission of energy resources has become one of the most pressing challenges. With superior stability and flexibility, voltage source converter (VSC) based high voltage direct current (HVDC) has emerged as a key technical solution for resource allocation. However, power fluctuation, devices operation, and lighting could lead to VSC-based HVDC system suffering severe transient overvoltage, which may damage critical devices. This paper focuses on the overvoltage mechanism analysis and suppression strategies. Firstly, modelling of VSC-based HVDC system, especially the devices in the station, was presented. Following which, the mechanisms, causes, and suppression strategies for major overvoltage types, including transient overvoltage (TO), switching overvoltage (SO), and lightning overvoltage (LO) were analyzed. Finally, a case study on a ±400 kV VSC-based HVDC station was simulated according to PSCAD software, and the results on switching overvoltage were provided and discussed, which validated the effectiveness of the mechanism analysis and overvoltage suppression strategy.