基于限流控制与保护协同的柔性直流配电线路整体保护方案  

Overall Protection Scheme for Flexible DC Distribution Lines Based on Synergy of Current Limiting Control and Protection

作　　者：杨乐 秦文萍[1] 陈晓乾 左鹏飞 蔡逸天 YANG Le;QIN Wenping;CHEN Xiaoqian;ZUO Pengfei;CAI Yitian(College of Electrical and Power Engineering,Taiyuan University of Technology,Taiyuan 030000,Shanxi Province,China)

机构地区：[1]太原理工大学电气与动力工程学院,山西省太原市030000

出　　处：《电网技术》2022年第12期4634-4644,共11页Power System Technology

基　　金：山西省科技重大专项项目资助(20181102028);国网山西省电力公司科技项目(520530200014)。

摘　　要：柔性直流配电线路故障后的过电流极高,需要通过限流的方式降低对高开断电流断路器的需求,而限流后现有的保护原理可能会失效,因此,限流技术与保护原理的结合已成为目前直流配电系统发展的迫切需求。为此,利用控保协同思想,提出了一种全周期限流控制策略与相关性保护原理协同的柔性直流配电线路整体保护方案,能够在限流的同时实现故障识别。所提出的全周期限流控制策略在故障发展的前、中、后期利用不同的限流环节有针对性地抑制故障电流,极大地减轻了直流配电网对于高开断电流断路器的需求;与此同时,利用Pearson相关系数综合描述线路两侧正负极电流极性及波形突变特征,可以同时识别区内外故障并且区分故障类型,减少保护冗余,在限流控制策略作用下仍能够可靠动作。在实时数字仿真器(real time digital simulator,RTDS)中的仿真结果表明:限流控制策略有效降低了故障电流,并且增强了线路两侧电流之间的相关性;保护能够可靠识别故障,不需要严格的通信同步,且不受过渡电阻、数据窗长和噪声的影响,有较好的应用前景。Due to the extremely high overcurrent after a fault in the flexible DC distribution lines,it is necessary to reduce the uses of the high breaking current circuit breakers by current limiting.However,the existing protection principles may refuse to operate after the current limiting.Therefore,the combination of current limiting technology and protection principles has become an urgent demand for the development of a DC distribution system.For this reason,this paper proposes an overall protection scheme for the flexible DC distribution lines based on the coordination of full-cycle current limiting control strategy and the correlation protection principles in order to realize the fault identification while limiting the current.The proposed full-cycle current limiting control strategy uses different current limiting links to suppress the fault current in the early,middle and late stages of the fault development,which greatly reduces the need for the high breaking current circuit breakers in the DC distribution network.Meanwhile,the protection principle of the Pearson correlation coefficient still operates reliably,simultaneously identifying faults,thus reducing the protection redundancy.Simulation results in the real time digital simulator(RTDS) show that the current limiting strategy effectively reduces the fault current and enhances the correlation between the currents on both sides of the circuit.The protection is able to reliably identify the faults without strict communication synchronization,and is not affected by the transition resistance,the data window length and the noise,having a good application prospect.

关 键 词：柔性直流配电网 控保协同 限流控制 相关性原理 故障线路识别 

分 类 号：TM721[电气工程—电力系统及自动化]