摘要
针对存在不对称情况的不接地系统与谐振接地系统,分析了接地故障前、后三相电压幅值的变化规律,提出可适应系统不对称的接地相识别方法:故障后若只有一相电压幅值相较于故障前降低,则此相为故障相;若有两相电压幅值降低,则中性点不接地系统中电压幅值升高相的滞后相为故障相,谐振接地系统过补偿状态下电压幅值升高相的超前相为故障相。所提方法简单实用,只需接地故障前、后三相电压幅值信息即可准确识别不对称状态下的接地故障相,且不受电压互感器测量误差的影响,在过渡电阻较大时也可准确识别故障相。数字仿真验证了理论分析和所提方法的正确性。
Aiming at ungrounding system and resonant grounded system with asymmetry,the magnitude variation rule of three-phase voltage before and after fault is analyzed.A grounding phase identification method suitable for asymmetric system is proposed.If there is only one phase whose voltage magnitude decreases after grounding fault compared with that before fault,this phase can be judged as fault phase.If two phase voltage magnitudes decrease,there are two possibilities:for neutral ungrounding system the lag phase of the phases whose voltage magnitude increase will be the fault phase;for the resonant grounded system,the lead phase of the phases whose voltage magnitude increase will be the fault phase.The proposed method is simple and practical,which can accurately identify the fault phase under asymmetrical state only by using the magnitude information of three-phase voltage before and after ground fault.Moreover,it can avoid the effect of measurement error of voltage transformer and accurately identify the fault phase when the transition resistance is large.The accuracy of the theoretical analysis and proposed method is verified by simulation.
作者
张林利
张毅
薛永端
王超
邵志敏
ZHANG Linli;ZHANG Yi;XUE Yongduan;WANG Chao;SHAO Zhimin(State Grid Shandong Electric Power Research Institute,Jinan 250003,China;State Grid Shandong Electric Power Company Weifang Power Supply Company,Weifang 261041,China;Department of Electrical Engineering,College of Information and Control Engineering,China University of Petroleum(East China),Qingdao 266580,China;Shandong Kehui Electric Co.,Ltd.,Jinan 250101,China)
出处
《电力自动化设备》
EI
CSCD
北大核心
2019年第4期24-29,共6页
Electric Power Automation Equipment
基金
国家自然科学基金资助项目(51477184)
国网山东省电力公司科技项目~~
关键词
小电流接地系统
单相接地
系统不对称
故障选相
non-solidly grounding system
single-phase grounding fault
system asymmetry
fault phase identification
