基于时序配合的柔直配电网后备保护与控制协同方案  

Time-sequential Coordination Based Collaborative Backup Protection and Control Scheme for Flexible DC Distribution network

作　　者：郑涛 吕文轩 ZHENG Tao;LYU Wenxuan(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市102206

出　　处：《电力系统自动化》2022年第2期137-145,共9页Automation of Electric Power Systems

基　　金：国家重点研发计划资助项目(2016YFB0900600);国家电网公司科技项目(521104180002)。

摘　　要：柔性直流配电网的故障主动控制与主保护协同方案能够有效克服传统保护方案的局限性,但在通信故障、隔离设备失灵等极端情况下其可靠性难以保证,亟须开展相关后备保护原理的研究。鉴于此,利用换流器的故障主动控制提出了一种基于本地电流突变量极性的后备保护方案:基于换流器产生的电流突变信号,根据测量的电流突变量极性闭锁故障反方向的负荷开关,进而根据时序配合关系实现故障线路的可靠隔离。该方案不依赖于通信及直流断路器,通过换流器的故障主动控制,仅利用负荷开关实现故障隔离。文中进一步提出了一种后备保护加速策略,并结合不同拓扑分析了其实用性。最后,在PSCAD/EMTDC中建立了四端柔性直流配电网模型,通过仿真验证了所提方案能够仅基于本地信息实现故障线路的快速选择性隔离。The collaborative active fault control and primary protection scheme for flexible DC distribution networks can effectively overcome the limitations of traditional protection schemes, but its reliability is difficult to be guaranteed in extreme cases such as communication and isolation equipment failure. Thus, it is urgent to carry out the research on relevant backup protection theory.Therefore, by utilizing the fault active control of the converter, a backup protection scheme based on the polarity of the local current sudden-change is proposed. Based on the current sudden-change generated by the converter, the protections of load switches in the reverse fault direction are blocked by measuring the polarity of the sudden-change current. Then, according to the time-sequential coordination relationship, the faulty line can be isolated reliably. This scheme is independent of communication and DC circuit breakers. Through active control of the converter, fault isolation can be realized by only using load switches. Besides,an acceleration strategy for the backup protection is proposed, and its practicability is analyzed in combination with different topologies. Finally, a four-terminal flexible DC distribution network model is established in PSCAD/EMTDC. Simulation results show that the proposed scheme can realize fast and selective isolation of faulty lines only based on local information.

关 键 词：故障主动控制 本地量保护 电流突变量极性 柔性直流配电网 后备保护 

分 类 号：TM721.1[电气工程—电力系统及自动化]