变压器和应涌流和励磁涌流识别新判据  

New judgment to identify sympathetic inrush and inrush current

作　　者：公茂法[1] 夏文华[1] 李国亮[1] 刘建平[1] 徐新源[1] 

机构地区：[1]山东科技大学信息与电气工程学院,山东青岛266590

出　　处：《电力系统保护与控制》2012年第18期139-143,共5页Power System Protection and Control

基　　金：山东省自然科学基金(ZR2012EEM021);山东科技大学研究生科技创新基金(YCA120108)

摘　　要：针对识别变压器和应涌流与励磁涌流这一差动保护的难题,提出一种利用瞬时频率变化率识别这两种电流的新判据。该判据对原电流信号进行经验模态分解(EMD),得到一组固有模态分量(IMF)后,对固有模态分量进行希尔伯特黄变换(HHT)得到瞬时频率。根据和应涌流和励磁涌流中含有大量高次谐波和非周期分量,而内部故障电流基本保持基频这一频率特性,将得到的瞬时频率进行微分,通过微分值的大小可判别该电流的性质。理论分析与仿真试验表明,该判据不受涌流中非周期分量的影响,不受间断角影响,并且能准确可靠地识别变压器和应涌流和励磁涌流。Aiming at the differential protection problem of identifying sympathetic inrush and inrush current, a new judgment to identify the two currents based on instantaneous frequency change rate is put forward. Empirical mode decomposition （EMD） is used to break up current signal into several intrinsic mode functions （IMFs）, and then instantaneous frequency is obtained through Hilbert-Huang transform （HHT）. According to the frequency characteristic that inrush current and sympathetic inrush current contain a large component of higher harmonics and aperiodic components, and internal fault currents always keep their basic frequency, the differential of instantaneous frequency is obtained. Then current signal can be distinguished by the differential＇s value. Theoretical analysis and simulation results show that this judgment is immune to the aperiodic component and dead angle. It can indentify the two currents correctly and reliability.

关 键 词：变压器 励磁涌流 和应涌流 频率特性 希尔伯特黄变换 

分 类 号：TM407[电气工程—电器] TM772