【作者】 刘飞霞； 夏向阳； 张琦；

【Author】 LIU Fei-xia;XIA Xiang-yang;ZHANG Qi;School of Electrical and Information Engineering,Changsha University of Science&Technology;

【机构】 长沙理工大学电气与信息工程学院；

【摘要】 对变压器励磁涌流和内部故障电流进行正确识别是变压器差动保护中的关键问题。变压器铁芯的高度非线性特征,导致励磁涌流波形出现明显的突变特征,利用小波理论对涌流特征进行提取,根据小波变换得出的模极大值进行鉴别。本文用Matlab构建变压器励磁涌流和内部故障电流仿真模型,利用小波函数对得到的波形进行多尺度辨析,通过观察模极大值的演化趋势,确定波形奇异性,从而得到可以定性地区分励磁涌流和内部故障电流的小波判据。对仿真模型设定不同的参数,可证明此方法不受变压器容量变化影响,可以很好地识别励磁涌流,有效避免由于误判而引起的变压器差动保护误动。更多还原

【Abstract】 Correct identification transformer inrush and internal fault current to prevent transformer differential protection is a key issue.Highly nonlinear characteristics of the transformer core result apparent characterization of mutations in inrush current waveform,using wavelet theory extract the inrush feature and identify the modulus maximum.Matlab build transformer inrush and internal fault current simulation model,wavelet function get the waveform obtained of multiscale analysis,through the observation of wavelet transform modulus maximum under multiscale evolution trend,determine the waveform singularity and qualitatively distinguish inrush and internal fault current.By setting different transformer parameters and simulation prove the method which doesn’t affect by transformer capacity can identify the transformer inrush and internal fault current and avoid misjudgment caused by transformer differential protection.更多还原