柔性直流和常规直流并联系统功率调制策略

Power modulation strategy for parallel system of MMC-HVDC and LCC-HVDC

由于柔性直流与常规直流控制特性的差异以及并联后的相互影响,其调制策略不同于常规直流。分析了柔性直流与常规直流并联系统的协调控制策略,阐述了功率限制功能的功率分配、速率分配和无功功率控制的实现方法。结合南方电网鲁西背靠背直流调制功能的RTDS仿真研究,针对试验中暴露的缺陷深入分析了并联系统在受端交流故障情况下限制直流功率的控制特性,提出了功率限制功能与高电压穿越控制功能的协调方法以及速率分配优化方法。仿真结果表明,优化后的并联系统可按照正确的时序和速率执行功率限制功能。

Due to the difference between MMC-HVDC and LCC-HVDC control characteristics and the mu-tual influence under parallel connection, the power modulation strategy of MMC-HVDC is different from that of LCC-HVDC. The coordinated control strategy of parallel system of MMC-HVDC and LCC-HVDC is analyzed, and the implementation methods of power dispatching and speed rate dispatching for power limitation function and reactive power control are expounded. Combined with RTDS simulation research of modulation function of Luxi back-to-back HVDC system, the control characteristics of power limitation function of the parallel system under the condition of AC fault at the receiving end are analyzed in view of the exposed defects. A coordination method of power limitation function and high-voltage ride-through control function and an optimization method of speed rate dispatching of power limitation function are proposed. Simulative results show that the optimized parallel system can perform power limitation function at a correct timing sequence and speed rate.