无源负荷侧无功功率快速供给的VSC-MTDC系统故障穿越协调控制  

Coordinated control for fault ride-through in VSC-MTDC system with quickly supply of reactive power to passive load

作　　者：王晓兰[1] 赵巧玲 WANG Xiaolan, ZHAO Qiaoling(College of Electrical and Information Engineering, Lanzhou University of Technology, Lanzhou 730050, China)

机构地区：[1]兰州理工大学电气工程与信息工程学院,甘肃兰州730050

出　　处：《电力自动化设备》2018年第11期28-34,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(50967001);甘肃省自然科学基金资助项目(1107RJZA272)~~

摘　　要：考虑到无源负荷对电压变化敏感,同时交流故障期间直流电压会出现大幅波动,研究了向无源负荷供电的基于电压源型换流器的多端直流输电(VSC-MTDC)系统交流故障穿越策略,提出了一种故障穿越协调控制方法:受端站在满足无功优先的原则下,依据交流电压跌落情况直接计算电流指令,仅采用电流内环控制以实现对无源负荷侧无功功率的快速供给,为负荷侧交流电压的恢复提供无功支持;为与受端站协调,连接电网的送端站也切换至快速电流控制,故障电流指令值由直流电压变化大小和方向直接计算得到,并满足多端VSC-MTDC系统的I-V下垂特性,以优先保证VSC-MTDC系统的有功需求,快速实现系统功率平衡,减小故障期间直流电压的波动幅度。在MATLAB/Simulink中搭建了向无源负荷供电的三端VSC-MTDC系统模型,仿真结果表明所提协调控制策略能够提高无源负荷的故障穿越能力,实现VSC-MTDC系统的稳定运行。Considering the facts that passive loads are sensitive to voltage drops and AC contingencies can result in large fluctuation in DC voltages,a coordinated control strategy of VSC-MTDC（ Voltage Source Converter based MultiTerminal Direct Current） system for AC fault ride-through is proposed. The passive stations directly calculate the current command values according to the AC voltage drop,in which priority is given to the reactive power. Only the current inner-loop control is implemented to provide rapid reactive power support on the passive load side,and consequently the AC voltage recovery at the demand side is ensured. In coordination,the controller at the grid side is also switched to rapid current control. The current demand values are directly calculated based on the variation in the value and direction of DC voltages,where I-V droop characteristics of multi-terminal VSC-HVDC system are satisfied,so as to guarantee the active power demand of VSC-MTDC system,balance the system power quickly and decrease the DC voltage variation during the fault period. A three-terminal VSC-MTDC system is established on the MATLAB/Simulink platform. Simulative results demonstrate that the proposed coordinated control strategy can effectively improve the AC fault ride-through ability and ensure the stable operation of VSC-MTDC system.

关 键 词：基于电压源型换流器的多端直流输电 无源负荷 电压跌落 故障穿越 协调控制 

分 类 号：TM721.1[电气工程—电力系统及自动化]