小波变换在微机母线保护中的应用研究

提出了一种利用小波变换原理精确地检测故障发生和差流出现的时刻，根据同步测量法的基本原理判断差流的出现是否是由于电流互感器馆和造成的，有效地防止了区外短路故障时，因此流互感器饱和造成的母线保护误动；并利用小波变换分析电流互感器饱和前后的暂态特性，准确地检测出故障电流进入饱和与退出饱和的时刻，有效地防止了故障由区外转入区内时，造成的母线保护拒动现象。仿真结果验证了上述算法的有效性。

Application of wavelet transform in micro-computer-based bus-bar protection

Regarding to the identification of current transformer(CT)saturation,a method is presented to prevent the bus bar protection relay from mal operation caused by CT saturation when out zone S/C happens.It detects precisely the fault occurrence time and the differential current appearing time by wavelet transform,and determines if the differential current is caused by the CT saturation according to the basic principle of synchronized measuring.The transient characteristics of CT before and after saturation are analyzed by wavelet transform to detect accurately the entering into saturation time and exiting from saturation time for preventing bus bar protection relay from reject operation when the fault moves from outside to inside.The simulative results prove its effectiveness.