摘要
多落点混合级联直流系统存在特有的模块化多电平换流器(MMC)功率盈余问题。当受端交流系统发生短路故障时,MMC过流、过压将引起MMC阀组闭锁,进一步可能导致系统功率中断。多落点混合级联直流系统整流侧采用电网换相型换流器(LCC)、逆变侧采用LCC与多台MMC级联。针对该系统提出一种适用于受端交流系统故障的故障电流限制方法,在逆变侧MMC控制中引入虚拟阻抗降低故障电流,无需额外添加设备。对虚拟阻抗的控制引入、计算以及投入实现过程进行了详细阐述,并在PSCAD/EMTDC中搭建模型进行仿真分析。结果表明,所设计的虚拟阻抗控制器可以实现故障电流的有效抑制,并防止功率倒送,从而实现混合级联直流系统的交流故障成功穿越和功率可靠传输。
There is a unique power surplus problem of modular multilevel converter(MMC) in multi-point hybrid cascaded DC system. When a short circuit fault occurs in the receiving end AC system,the MMC overcurrent and overvoltage will cause the MMC valve blocked,which may further cause system power interrupted. The rectifier-side of multi-point hybrid cascaded DC system adopts the line commutated converter(LCC),and the inverter-side adopts the cascade connection of LCC and multiple MMCs. A fault current suppression method suitable for fail occurred at receiving end AC system is proposed. The fault current is reduced by introducing a virtual impedance in the MMC control at inverter side without additional equipment. The control introduction,calculation and input realization process of virtual impedance are elaborated in detail,and a model is built in PSCAD/EMTDC for simulation analysis. The results show that the designed virtual impedance controller can realize the fault current suppression effectively and prevent power reversal,so as to achieve the successful ride-through of AC faults and reliable power transmission of hybrid cascaded DC system.
作者
吴海艳
江琴
李保宏
刘天琪
张敏
王腾鑫
WU Haiyan;JIANG Qin;LI Baohong;LIU Tianqi;ZHANG Min;WANG Tengxin(College of Electrical Engineering,Sichuan University,Chengdu 610065,China;Electric Power Research Institute of State Grid Shanxi Electric Power Co.,Ltd.,Taiyuan 030012,China)
出处
《电力自动化设备》
EI
CSCD
北大核心
2023年第2期191-196,202,共7页
Electric Power Automation Equipment
基金
国家电网公司科技项目(5100-202199274A-0-0-00)。
关键词
多落点混合级联直流系统
协调控制策略
故障穿越
限流措施
虚拟阻抗
multi-point hybrid cascaded DC system
coordinated control strategy
fault ride-through
current limiting measurements
virtual impedance
