基于电压源型换流器的电压-电流特性研究了电压下垂控制策略.为解决下垂控制在风功率注入较低时,直流线路功耗相对较大的问题,采用引入障碍函数的内点算法研究了一种基于最优功率潮流的电压控制策略,实现母线电压稳定,并调整系统以最小的线路功耗输送电能;故障时系统切换至下垂控制,实现换流站的自主协调控制.最后,以4端输电系统为例,采用MATLAB编程和Optimization Tool计算系统稳态运行点,验证2种控制策略的有效性;结果表明,所提策略能够实现多端直流输电系统换流站间的电能分配,而最优电压控制为网侧换流站提供更为合适的电力调度电压参数.%A voltage droop control strategy is studied based on the analysis of voltage-current characteristics of voltage source converters. When the injection from power wind farms is lower,the system loss on DC lines will increase under droop control strategy. To solve this problem,a voltage control strategy is proposed using interior point algorithm with barrier function. In this way,the bus voltage is kept steady,and the system can transmit power with minimum loss. Moreover,the system can switch to voltage droop control under fault,which realizes a self-regulated control. At last, MATLAB programming and Optimization Tool are used to calculate the equilibrium operation points and verify the effec-tiveness of two control strategies in a four-terminal transmission system. Results show that the proposed strategy can achieve power dispatching,while the optimal voltage control can provide more suitable voltage regulation parameters for grid-side inverters.
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