利用二次小波变换区分变压器励磁涌流和短路电流的符号法  

Sign identifying method to discriminate inrush current and fault current of transformer based on twice wavelet

作　　者：陈晓东[1] 柳亦钢[1] 李天云[2] 

机构地区：[1]广东省电力调度中心调度部,广东广州510600 [2]东北电力学院电力系,吉林吉林132012

出　　处：《电力自动化设备》2006年第6期48-52,共5页Electric Power Automation Equipment

摘　　要：通过选取合适的小波基函数,利用小波变换对采样得到的差流进行一次或二次小波变换,再提取小波变换系数的局部模极大值符号,利用定义的符号识别公式即可区分对称性涌流、非对称性涌流以及内部故障电流,还能鉴别出励磁涌流伴随内部故障情况以及电流互感器饱和采样得到的励磁涌流。Matlab仿真及动模实验校验表明,该方法简单有效,不受噪声干扰,易于在工程上实现。With selected appropriate wavelet fundamental functions,the sampled differential current is transformed once or twice,and with the extracted sign of the local modulus maximum of wavelet coefficients and the defined sign identification function,the symmetrical inrush,the asymmetrical inrush and the internal fault current are distinguished from each other,as well as the excitation inrush accompanying with the internal fault current or the current transformer saturation is distinguished. Simulations with Matlab and experiments prove that the method is simple,effective, free from noise and easy to be implemented.

关 键 词：变压器差动保护 小波变换 模极大值 符号识别法 

分 类 号：TM771[电气工程—电力系统及自动化]