和应涌流导致差动保护误动模式及原因研究  

Mode and Reason Analysis of Differential Protection Mal-Operation Caused by Sympathetic Inrush

作　　者：孙向飞[1] 周建萍[1] 夏聆峰 孙士云[1] 

机构地区：[1]昆明理工大学电力工程学院,云南昆明650500

出　　处：《昆明理工大学学报（自然科学版）》2015年第2期73-79,129,共8页Journal of Kunming University of Science and Technology(Natural Science)

基　　金：国家自然科学基金项目(51007035;51367009);云南省自然科学基金项目(2009ZC016M)

摘　　要：目前和应涌流造成差动保护误动的报道及原因分析,主要针对独立的单个事件,缺乏对和应涌流导致差动保护误动模式的全面分析以及误动本质原因的深入研究.为此,在全面统计分析国内外和应涌流导致差动保护误动实例的基础上,归纳分析了发生和应涌流的运行模式,分别研究了并联与级联和应涌流导致CT暂态饱和后对差流的二次谐波和间断角的影响,揭示了级联和应涌流更容易引起差动保护误动的内在原因,并依据实际运行情况,重点考虑负荷电流的影响.研究表明,并联和应涌流易导致系统侧CT饱和,此时差流即为和应涌流,差流基波分量减小,而负荷电流为正弦量不含二次谐波,即差流的二次谐波含量上升,差流间断角亦较大;而级联和应涌流易引起负荷侧CT饱和,此时差流为负的和应涌流,差流的二次谐波分量减小,差流间断角亦变得很小,可能导致现有的涌流制动环节失效,容易引起变压器差动保护误动作.仿真和实例统计结果均验证了理论分析的正确性.At present,the analysis and research of differential protection mal -operation caused by sympathetic inrush are not sufficient because reports and reason analysis are mainly focused on irrelevant single incidents.The occurrence modes and characteristics are therefore firstly summarized based on statistics and analysis of differential protection mal -operation cases caused by sympathetic inrush reported at home and abroad.Then,the influences of CT saturation on the second harmonic proportion and dead angle of differential current are investigated.The internal reasons for series sympa-thetic inrush causing differential protection mal -operation easier are also revealed.Moreover,according to the actual op-erating conditions,the impact of load current is mainly considered.The results show that parallel sympathetic inrush may lead to system-side CT saturation;second harmonic ratio of differential current increases and dead angle is large.On the contrary,series sympathetic inrush easily causes load -side CT saturation,and this will lead to second harmonic ratio lower than threshold and dead angle reduced.Thus,second harmonic restraint is invalid and differential protection may mal -operate.The simulation and case statistics verify the validity of theoretical analysis.

关 键 词：和应涌流 电流互感器饱和 差动保护 变化器 

分 类 号：TM76[电气工程—电力系统及自动化]