柔性多状态开关的改进协调控制策略*

Research on Improved Coordination Control Strategy for Soft Open Point

  • 摘要: 在分布式新能源技术的快速发展下,柔性多状态开关(Soft open point,SOP)的各端口协调控制对配电网的稳定运行至关重要。当SOP采用主从控制时,只有定直流电压控制的主换流器进行功率平衡。然而,当系统出现较大的功率波动时,有主换流器功率超调和直流侧电压越限的问题出现。为了防止只有单个换流站进行功率调节而影响系统的稳定运行,提出一种改进型协调控制策略。利用直流电压波动值与系统中不平衡功率的正相关性,在定功率外环控制器引入直流电压变化跟随器,动态调整从换流器的功率指令值,进而使从换流器在功率波动时也参与功率调节。该策略使多个换流器同时参与功率调节,且SOP可以在不同控制模式中平滑切换。最后,搭建了三端SOP的PLECS仿真模型,验证了改进协调控制策略的正确性和有效性。

     

    Abstract: Under the rapid development of distributed new energy technology, the coordinated control of each port of soft open point (SOP) is crucial to the stable operation of the distribution network. When the SOP adopts master-slave control, only the converter controlled by the fixed DC voltage participates in the regulation. However, when there is a large power fluctuation in the system, the problems of overshoot of the power of the main converter and over-limit of the DC side voltage appear. In order to prevent the stable operation of the system from being affected by only a single converter station performing power regulation, an improved coordinated control strategy is proposed. Using the DC voltage fluctuation and the imbalance of power in the system are relevance, was introduced to the rated power loop controller dc voltage follower change, make the inverter also participate in power regulation when the power imbalance in the system. This strategy enables multiple converters to participate in power regulation at the same time, and the SOP can be smoothly switched in different control modes. Finally, the PLECS simulation model of three-terminal SOP is built to verify the correctness and effectiveness of the improved coordination control strategy.

     

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