±800kV/8000MW分址级联特高压直流输电工程系统设计研究OA

To optimize clean energy integration efficiency,enhance system flexibility,the site-separated cascaded ultra-high voltage direct current(UHVDC)transmission project was developed.This paper proposes an innovative system design for a±800 kV UHVDC site-separated cascaded transmission project.It conducts in-depth research and discussion on the main circuit topology and operation modes,insulation coordination and air clearance,DC control and protection strategies,and lean equipment design.Several site-separated cascaded main circuit schemes are compared and optimized,significantly improving the operational flexibility and reliability of the DC system.A graded arrester configuration is proposed to reduce energy levels effectively.A multi-terminal coordinated site-separated cascaded control and protection system and an integrated monitoring solution are introduced,ensure stable and adaptive operation of the DC system under complex topologies.Additionally,lean design schemes for converter valves and converter transformers under high-altitude conditions are presented,significantly reducing equipment costs.The research findings of this paper have been applied to the Jinshang-Hubei±800 kV UHVDC transmission project and provide theoretical and practical support for the system design of future multi-terminal UHVDC transmission projects.