基于差流基波分量相位的励磁涌流识别新方法  

A New Method of Inrush Current Identification Based on Differential Current Fundamental Wave Phase

作　　者：谢广宇 孙向飞[1] 林湘 XIE Guangyu;SUN Xiangfei;LIN Xiang(School of Electrical Power Engineering,Kunming University of Science and Technology,Kunming 650500,Yunnan,China)

机构地区：[1]昆明理工大学电力工程学院,云南昆明650500

出　　处：《电网与清洁能源》2020年第10期20-27,共8页Power System and Clean Energy

基　　金：国家自然科学基金资助项目(51007035,U1202233);云南省自然科学基金资助项目(2009ZC016M)。

摘　　要：基于二次谐波闭锁判据的差动保护算法,在面对励磁涌流二次谐波含量低于门槛值以及空合故障变压器这两类情况时,很难在动作可靠性上做到平衡。根据单相涌流二次谐波含量求取方法,文章分析了励磁涌流二次谐波含量低于门槛值时单相涌流的性质:当三相励磁涌流二次谐波含量低于门槛值时,两相涌流饱和程度较大,另一相饱和程度较轻或不饱和;当两相励磁涌流二次谐波含量低于门槛值时,一相涌流饱和程度较大。利用上述性质,根据三相差流二次谐波含量的不同情况,结合二次谐波闭锁判据,文章提出了励磁涌流基波分量相位辅助判据。MATLAB/Simulink仿真实验验证了算法的可行性,当三相励磁涌流二次谐波含量均低于门槛值时,算法能够正确闭锁差动保护。With the differential protection algorithm based on second harmonic blocking criterion it is difficult to balance the operation reliability when the following two cases are faced:(1) the second harmonic content of inrush current is lower than the threshold value(2) an air-closed fault occurs to the transformer.According to the method of obtaining the second harmonic content of single-phase inrush current, this paper analyzes the characteristics of single-phase inrush current when the second harmonic content of inrush current is lower than the threshold value.It is found that when the second harmonic content of the threephase inrush current is lower than the threshold value,the saturation degree of two-phase inrush current is larger,while the saturation degree of the other phase is lighter or unsaturated. When the second harmonic content of two-phase inrush current is lower than the threshold value,the saturation degree of one-phase inrush current is larger. According to the above characteristics and based on different contents of the second harmonic in the three-phase differential current as well as the second harmonic locking criterion,a phase-assisted criterion for the fundamental component of the inrush current is proposed in this paper. The feasibility of the algorithm is verified by MATLAB/Simulink simulation experiments.The result shows that when the harmonic content is lower than the threshold value,the algorithm can correctly block the differential protection.

关 键 词：变压器 差动保护 励磁涌流 二次谐波闭锁判据 

分 类 号：TM771[电气工程—电力系统及自动化]