适用于多端柔性直流输电系统的优化下垂控制策略

电压下垂控制策略适用于换流站数目较多以及功率波动频繁的多端柔性直流输电系统,针对下垂系数计算繁琐、个别换流站功率越限及下垂系数对控制性能影响等问题,提出了优化下垂控制策略。该策略以优化下垂系数为基础,结合电压裕度控制,给出有功功率—电压特性曲线,实现了功率的合理分配。在MATLAB/Simulink下搭建的四端柔性直流输电系统仿真表明,该控制策略可以避免下垂系数设置不当造成的控制问题,能够合理分配各换流站有功功率,快速稳定直流母线电压。

Optimized Droop Control Strategy for Voltage Source Converter Based Multi-terminal Direct Current System

The voltage droop controller is fairly suitable for the voltage source converter based multi-terminal direct current(VSC-MTDC)system when the system has more converter stations or the system power fluctuation is high. But many problems will occur when using traditional voltage droop control. A novel optimized droop control strategy is proposed for solving the problem caused by the inappropriate droop slope and complex VSC-MTDC system. It mixes together traditional voltage droop control and voltage margin control, and then provides the active power-voltage characteristic curve of optimized droop control. A four-terminal voltage source converter based high voltage direct current transmission system is built for simulation verification based on MATLAB/Simulink. Simulation results show that the optimized droop control can avoid problems caused by droop oversized or undersized slope, could reasonably allocate the active power of the stations and quickly stabilize direct current voltage.