利用正序电压余弦分量变化量识别振荡期间线路对称故障方法  

Symmetrical Fault Identification During Power Swinging Based on Positive Sequence Voltage Cosine Component Deviation

作　　者：王兴国 张晓东 程琪 徐翀 刘宇 夏秋 WANG Xingguo;ZHANG Xiaodong;CHEN Qi;XU Chong;LIU Yu;XIA Qiu(State Key Laboratory of Power Grid Safety and Energy Conservation(China Electric Power Research Institute),Haidian District,Beijing 100192,China;State Grid Corporation of China,Xicheng District,Beijing 100031,China;State Grid Economic and Technological Research Institute Co.,Ltd.,Changping District,Beijing 102209,China)

机构地区：[1]电网安全与节能国家重点实验室(中国电力科学研究院有限公司),北京市海淀区100192 [2]国家电网有限公司,北京市西城区100031 [3]国网经济技术研究院有限公司,北京市昌平区102209

出　　处：《电网技术》2022年第9期3623-3632,共10页Power System Technology

摘　　要：电力系统振荡会导致输电线路距离保护误动作,振荡期间须闭锁距离保护,在振荡闭锁期间线路发生对称故障时须准确识别并开放距离保护。针对现有振荡闭锁期间线路发生对称故障时,保护动作时间长,故障识别灵敏度低的问题,提出一种利用保护安装处正序电压余弦分量变化量的快速识别振荡期间对称故障的方法,利用启动元件动作前后正序电压余弦分量差异构造振荡期间对称故障的识别判据,系统振荡期间,正序电压余弦分量变化量较小,对称故障时正序电压余弦分量变化量大,利用以上差异,实现了振荡期间对称故障快速准确识别,开放距离保护,快速切除对称故障。RTDS仿真结果验证了所提方法的有效性。Transmission line distance protection may be mal-operated during a power swing,cutting off the non-fault lines,so it is necessary to block the distance protection during the power swing.But when a symmetrical fault occurs during the power swing,the distance protection should be switched on to identify the fault quickly.Generally,it may take a long time to identify the fault and the identification sensitivity of the existing symmetric fault identification methods is rather low.Aiming at this problem,a fast symmetric fault identification method during the power swing based on the cosine component variation of the positive sequence voltage is proposed in this paper.The identification criterion of the symmetric fault during a swing is determined based on the characteristics of the cosine component of the positive sequence voltage before and after the element operation starts.The cosine component of the positive sequence voltage seldom changes for a power swing,while it changes greatly for a symmetric fault during the power swing.Based on the above differences,the blocking of the distance protection is realized,and the symmetric faults are identified quickly and accurately.Combined with the action characteristics of distance protection,the symmetric faults are timely cleared off.The RTDS(Real Time Digital System)simulation results verify the effectiveness of this method.

关 键 词：输电线路 距离保护 系统振荡 对称故障 正序电压余弦分量 

分 类 号：TM721[电气工程—电力系统及自动化]