交直流微电网群的多端直流互联与潮流优化技术研究

By interconnecting the microgrids, a larger scale of aggregated cluster i.e. multi-microgrids can be formed. With the microgrids supporting each other, the reliability of the system is enhanced. Meanwhile, the overall performance of the multi-microgrids can be improved by further optimization of power flow via the interconnection system. This project first studies the interconnection scheme and its interconnection characteristics of multi-microgrids based on the multi-terminal DC system, in which way different types of microgrids can be interconnected compliantly. The integrated control schemes of the converters in the multi-terminal DC system with adaptive impedance droop control and global voltage information based autonomous control are designed to achieve the stable operation of multi-microgrids. On this basis, a novel topology of interline DC power flow controller based on modular multilevel converter is proposed. Furthermore, the method of its realizing well-allocated power flow control in multi-terminal DC system is studied. The dynamic and stochastic characteristics of the sub-microgrids in the multi-microgrids are analyzed. A multi-objective dynamic stochastic optimal power flow problem concerning economic and safe operation, efficient using of new energy and suppressing power fluctuations is studied, and a comprehensive solution of optimal power flow in multi-microgrids is derived. Finally, the research content of this project is formed into a theoretical system, which provides theoretical reference and technical support for organizing economical, reliable and flexible multi-microgrids.

将微电网进行互联，使之形成更大规模的聚合群体，微电网之间相互支撑，系统的可靠性得以增强。同时，可通过互连线对微电网间的能量流动做进一步优化，实现微电网群综合性能的提升。本项目首先研究基于多端直流系统的微电网群互联方案及其互联特性，实现不同类型微电网间的高兼容互联；设计带有自适应阻抗式下垂控制与全局电压信息自主控制的多端直流系统换流器综合控制方案，解决微电网群的稳定运行问题。以此为基础，提出基于模块化多电平换流器的新型线间直流潮流控制器，研究其应用在多端直流系统中实现高调配度潮流控制的方法措施；分析微电网群中子微电网的动态和随机特性，研究涵盖经济安全运行、新能源高效利用与功率波动抑制的微电网群多目标动态随机潮流优化方法，给出微电网群潮流优化综合解决方案。最后，将本项目的研究内容形成理论体系，为组建经济、可靠、灵活的微电网群提供理论借鉴与技术支持。