大规模海上风电多电压等级混合级联直流送出系统

海上风电场拥有更加丰富与稳定的风能资源,同时具备适宜大规模开发的优点,发展潜力巨大,是未来风电的主要发展趋势.文中总结分析了现有工程和理论研究中涉及的大规模海上风电直流送出拓扑,包括仅采用模块化多电平换流器的柔性直流换流站系统和二极管整流单元-模块化多电平换流器混合直流换流站系统,归纳了各方案的运行特点.为解决现有方案运行灵活性低、可行性差的问题,提出了一种多电压等级混合级联直流送出系统,从技术性和经济性两方面对方案进行了对比分析.最后,设计了多电压等级混合级联直流送出系统协调控制策略,通过PSCAD/EMTDC仿真分析对并网方案进行了可行性验证.

Hybrid Cascaded HVDC Transmission System with Multiple Voltage Levels for Large-scale Offshore Wind Power

Offshore wind farm has more abundant and stable wind energy resources, and has the advantages suitable for large-scale development. It has great development potential and is the main development trend of wind power in the future. This paper summarizes and analyzes the high voltage direct current (HVDC) transmission topologies for the large-scale offshore wind power involved in the existing engineering and theoretical research, including the flexible DC converter station system using only modular multilevel converter (MMC) and the hybrid HVDC converter station system using diode rectifier unit (DRU-MMC). The operation characteristics of each scheme are summarized. In order to solve the problems of low flexibility and feasibility of the existing schemes, a hybrid cascaded HVDC transmission system with multiple voltage levels is proposed, and the schemes are compared and analyzed from the perspectives of technology and economy. Finally, the coordinated control strategy for the hybrid cascaded HVDC transmission system with multiple voltage levels is designed, and the feasibility of the grid integration scheme is verified by PSCAD/EMTDC simulation analysis.