含多线路直流潮流控制器的多端直流环网非瞬时断路故障特征及控制保护策略  

Characteristics and Control & Protection Strategy of a Multi-line CFC Integrated M^(2)TDC Grid Under Non-instantaneous Open-circuit Faults

作　　者：王谱宇 王松 张静怡 张小平[2] 郭春义 WANG Puyu;WANG Song;ZHANG Jingyi;ZHANG Xiaoping;GUO Chunyi(School of Automation,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu Province,China;School of Engineering,University of Birmingham,Birmingham B152TT,UK;State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]南京理工大学自动化学院,江苏省南京市210094 [2]英国伯明翰大学工学院,英国伯明翰市B152TT [3]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206

出　　处：《电网技术》2022年第1期90-100,共11页Power System Technology

基　　金：国家自然科学基金项目(51807091);英国工程物理科学基金项目(EP/N032888/1);新能源电力系统国家重点实验室开放课题资助(LAPS20016)。

摘　　要：随着多端直流输电(multi-terminal HVDC,MTDC)技术的快速发展,直流网络换流站间的互联度进一步提升,已逐步形成环网(meshed MTDC,M^(2)TDC)拓扑。环网中某条线路发生断路故障,必然引起网络控制自由度(degree of freedom,DF)减小,针对含多线路直流潮流控制器(current flow controller,CFC)的M^(2)TDC发生不同位置非瞬时断路故障下的故障特征进行研究,主要有3个贡献:1)发生近端故障时,提出CFC控制度切换策略,快速切除故障线路上的子模块(sub-module,SM),使之退出运行;2)当负责CFC电容电压稳定控制的SM所在线路发生近端故障时,提出基于SM控制量切换控制的电容电压稳定控制方法,保证CFC的正常工作;3)发生远端故障时,分析故障特征和CFC保护动作必要性,基于线路潮流的控制优先级,旁路控制对应的SM,使CFC控制度与M^(2)TDC的DF相匹,保证M^(2)TDC线路潮流的稳定控制。最后,在PSCAD/EMTDC仿真平台上建立含4线路CFC的5端直流环网(MT_(5)DC),当不同位置发生非瞬时断路故障时,评估不同SM退出运行对系统运行性能的影响,仿真结果验证了所提出的控制保护策略可大幅提升CFC的控制灵活性和发生近/远端故障下的控制保护能力,保证发生不同断路故障时,CFC保持稳定运行的能力,提升M^(2)TDC发生非瞬时断路故障时的潮流可控性。With the increasing complexity of the Meshed Multi-terminal HVDC (M^(2)TDC),a transmission line in the meshed grid is disconnected due to a fault,which will lead to a decrease in the degree of freedom (DF) of control.This paper analyzes the fault characteristics of an M^(2)TDC including a multi-line DC current flow controller (CFC) under non-instantaneous disconnected faults and has got three contributions:1) When a fault occurs at the near end,a switching control strategy of the CFC is proposed to quickly remove the sub-module (SM) on the faulted line,quitting its running;2) When a fault occurs at the near-end line where the SM is responsible for the CFC capacitor voltage control,a SMswitching control for the capacitor voltage stability is proposed to ensure the normal operations of the CFC;3) When a fault occurs at the remote end,the fault characteristics and the necessity of the CFC control and protection actions are analyzed.An active SM bypassing control is proposed to match the CFC control degree with the DF of the M^(2)TDC.Finally,a five-terminal HVDC (MT_(5)DC) network with a four-line CFC is established on the PSCAD/EMTDC.When the non-transient disconnected faults occur at different locations,the impacts of different SMs quitting operations on the system performance are evaluated,which verifies that the proposed strategies can greatly improve the control flexibility and protection ability of the CFC in case of the near/remote-end faults.These strategies may ensure the stable operations of the CFC and the control ability of the power flow of the M^(2)TDC grid under non-transient disconnected fault conditions.

关 键 词：多端直流环网(M^(2)TDC) 直流潮流控制器(CFC) 控制自由度(DF) CFC控制度 非瞬时断路故障 近/远端故障 控制保护策略 子模块控制量切换策略 

分 类 号：TM721[电气工程—电力系统及自动化]