基于直流电流过零特征的柔性直流配电网保护方案研究  

Research on Protection Scheme of Flexible DC Distribution Grids Based on DC Current Zero-crossing Characteristics

作　　者：郑涛 吴琼 吕文轩 王兴国 曹虹 ZHENG Tao;WU Qiong;LÜWenxuan;WANG Xingguo;CAO Hong(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China;China Electric Power Research Institute,Haidian District,Beijing 100192,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),北京市昌平区102206 [2]中国电力科学研究院有限公司,北京市海淀区100192

出　　处：《电网技术》2020年第5期1806-1814,共9页Power System Technology

基　　金：国家重点研发计划项目(智能电网技术与装备重点专项)(2016YFB0900600);国家电网公司科技项目(521104180002)。

摘　　要：直流线路故障的快速、可靠识别,是柔性直流配电网发展在继电保护方面所面临的技术难点之一。针对基于具有直流故障自清除能力换流器的柔性直流配电系统,重点研究系统双极短路故障时的故障特性,并利用其故障电流迅速增大的特点,提出基于直流电流过零检测的保护方案。方案通过识别线路两端出现直流电流过零时刻的异同,确定故障线路并完成故障隔离。该保护方案原理简单且易于实现,能够快速识别故障线路。在PSCAD/EMTDC仿真软件中搭建柔性直流配电系统模型,通过大量仿真验证了该保护方案的可行性。Rapid and reliable identification of DC line faults is one of the technical difficulties faced by development of flexible DC distribution networks in protective relaying. The paper focuses on the fault characteristics of the flexible DC power distribution system based on DC fault self-cleaning converters in the event of bipolar short-circuit fault. With the characteristics of rapidly increasing fault current, a protection scheme based on detection of DC current zero-crossings at both ends of the line is proposed. The scheme locates the short-circuit fault by identifying the differences of DC current zero-crossings quickly and reliably and removing the fault rapidly. Feasibility of the proposed protection scheme is verified with a large number of simulations on PSCAD/EMTDC platform.

关 键 词：柔性直流配电网 FBSM-MMC 电流过零 故障识别 

分 类 号：TM721[电气工程—电力系统及自动化]