基于小波变换的电力变压器继电保护研究

以小波变换中多分辨分析为理论依据，对电流信号进行多尺度小波分解，提取各尺度高频段能量，提出小波能量法，该方法以不同尺度能量变化之比为判据，对变压器的励磁涌流和内部短路电流进行区分。使用 SIMULINK搭建模型对励磁涌流与短路电流的仿真，得到两者波形。通过小波工具箱提取两者的高频系数，得到各尺度能量。仿真实验结果表明，该方法计算简单便利，能够对励磁涌流和短路电流进行有效地区分。

Research on power transformer relay protection based on wavelet transform

In this paper a new method based on multi-resolution analysis of wavelet transform is presented to distinguish the inrush current and internal faults with the ratio of energy change rate as the criterion.This algorithm is called the wavelet energy method.This research uses SIMULINK to build simulation models of inrush current and short-circuit current to get waveforms of them.The high frequency coefficients of the two are extracted by wavelet toolbox,and the energy of each scale is obtained.Simulation results show that the method is simple,convenient and it is capable to distinguish inrush current and short-circuit currents effectively.