多端柔性直流输配系统控制策略研究

Research on the Control Strategy of Multipoint Flexible DC Transmission and Distribution Systems

多端柔性直流输配电系统能够实现多电源供电、多落点受电、孤岛供电以及有利于分布式能源和风电并网的优点,比双端系统更为灵活、可靠性更高。针对多端直流输配电系统的控制系统结构以及暂态故障时直流电压与系统潮流控制存在问题,分别提出了主从控制与电压跌落控制相结合的控制方法,有效的解决了多端系统中换流端口出现故障而引起的系统波动的问题,最后利用PSCAD软件对一个四端系统进行仿真,其仿真结果验证了该控制策略的正确性和有效性。

Muhipcint flexible DC transmission and distribution system can achieve adventages of multiple feed, multiple falling point power, islet power supply and beneficial to distributed energy source and wind-power combined with network. his more flexible and higher reliability than the double-terminal system. For the control system structure of the multipoint DC transmission and distribution and the problems of DC voltage and the system flow control for transient state fault, the control method of the master-slave control combined with voltage drop-off control are put forward, It can efficiently solve the system undulant problem which is caused by the converter inlet fault of the muhipoint system. Finally use PSCAD software to simulate a four-terminal system,its simulation result shows validity and effectiveness of the control strategy.