Review on key technologies of DC high speed switch in a multi-terminal UHVDC system

Abstract

Multi-terminal HVDC (High Voltage Direct Current Transmission) technology is one of the effective technologies to solve the shortage of transmission corridors and connection issues of large-scale renewable energy grid in China. The function of a High Speed Switch (HSS) is to implement on-line switching and fault isolation of the third station in a multi-terminal HVDC system. However, 800kV HSS still relies on importation and 800kV HSS has become a “neck-jamming” equipment for the development of the multi-terminal HVDC transmission system. In order to obtain the core technologies, this paper first briefly introduces the roles of a HSS played in a multi-terminal hybrid HVDC project, and summaries the operating conditions and key technical parameters. Secondly, this paper focuses on the long-term arcing tolerance ability and DC breaking capability without oscillation circuits required by a 800kV HSS. Further, its research and development status are investigated. Finally, suggestions for the future research directions are given for 800kV HSS localization.