采用能量平衡性分析的MMC柔直系统自适应功率控制策略  

Adaptive Power Control Strategy for Flexible and Straight System Based on Energy Balance Analysis

作　　者：陈敦辉 洪潮 谈竹奎 王冕 陈雁 徐玉韬 刘斌 代奇迹 CHEN Dunhui;HONG Chao;TAN Zhukui;WANG Mian;CHEN Yan;XU Yutao;LIU Bin;DAI Qiji(Electric Power Research Institute of Guizhou Power Grid Co.,Ltd.,Guiyang 550007,Guizhou Province,China;State Key Laboratory of HVDC,Electric Power Research Institute,CSG Guangzhou 510663,Guangdong Province,China)

机构地区：[1]贵州电力科学研究院,贵州省责阳市550007 [2]南方电网科学研究院直流输电技术国家重点实验室,广东省广州市510663

出　　处：《中国电机工程学报》2020年第7期2255-2268,共14页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51667007);中国南方电网公司重点科技项目(GZKJQQ00000417)。

摘　　要：基于模块化多电平换流器(modular multilevel converter,MMC)的柔性直流输电系统在电力传输方面具有更好的灵活性和可控制性,但必须保证在不同控制目标和运行工况下直流侧电压的动态稳定性。该文利用电容等效的方法对上下桥臂进行数学建模,基于电容充放电过程中的能量交换关系推导并阐明了换流站直流电压变化机理;针对换流站外环功率控制,为减少交直流侧功率不平衡度,提高直流电压动态稳定性,提出了一种动态自适应功率控制策略,该调整策略可以显著改善换流站工况调整时直流电压动态性能,提高柔直系统交流侧故障时直流电压的稳定性;最后搭建仿真模型分析验证了所提策略在提高柔直系统动态过程中直流电压的稳定性及针对严重故障的适应性方面具有显著效果。The flexible DC transmission system based on modular multilevel converter(MMC)has better flexibility and controllability in power transmission,but the dynamic stability of DC voltage must be guaranteed under different control objectives and operating conditions.In this paper,the variable capacitor was used to model the upper and lower arm of the bridge.Based on the analysis of the energy exchange relation in the process of capacitor charging and discharging,the DC voltage variation mechanism of the converter station was deduced and clarified.In this paper,a dynamic adaptive power control strategy was proposed to reduce the unbalance degree of AC and DC power and improve the dynamic stability of DC voltage.Finally,a simulation model was built to verify the effectiveness of the proposed strategy in improving DC voltage stability and adapting the flexible system to severe faults.

关 键 词：柔性直流 电容等效 功率不平衡度 动态稳定性 自适应 

分 类 号：TM732[电气工程—电力系统及自动化]