多端柔性直流输电系统的直流电压优化控制策略

为提高多端柔性直流输电系统的运行稳定性,本文提出了一种适用于多端系统的直流电压优化控制策略。该策略结合了直流电压偏差控制策略和直流电压下垂控制策略的优点,通过直流电压的变化量来协调各换流站的工作方式,从而确保不同工况下直流网络内功率的平衡。当系统潮流波动较小时,部分与有源系统相连的换流站参与潮流调节,保持系统稳定;当潮流突变且波动剧烈时,与有源系统相连的所有换流站共同参与潮流调节,一起稳定直流电压,避免直流电压的过大波动。最后,在Matlab/Simulink仿真平台中进行了仿真分析,仿真结果验证了该策略的正确性与可行性。

A DC Voltage Optimal Control Strategy for VSC-MTDC Systems

In order to improve the stability of VSC-MTDC systems, a DC voltage optimal control strategy that is suitable to multi-terminal HVDC systems is proposed. This strategy combines the advantages of DC voltage deviation control strategy and DC voltage droop control strategy. In order to balance system power in different conditions, each converter station is coordinated by the changed amount of DC voltage. When there is a small fluctuation in power system, a part of converter stations that are connected to the active system will be applied to adjust system power to maintain system stability. When a large fluctuation occurs in power system, all converter stations that are connected to the active system will be applied to adjust system power to maintain the stability of DC voltage, and therefore to avoid big changes of DC voltage. In the end, the characteristics of DC voltage optimal control strategy are simulated and analyzed in Matlab/Simulink simulation platform, and simulation results verify its validity and feasibility.