基于二维离散平稳小波变换的短时电能质量扰动检测方法

基于二维离散平稳小波变换，提出了一种精确定位短时电能质量扰动起止时刻的检测方法。利用二维小波变换将信号分解在3个不同的高频方向，用水平高频系数精确定位发生在工频相位过零点的电压凹陷的起止时刻，用垂直高频与斜线高频系数之和精确定位发生在工频相位非过零点的电压凹陷的起止时刻。该方法只需采用最简单的小波函数db1对信号进行1层小波变换，简单易行且对噪声不敏感。运用Matlab6.5进行仿真实验，验证了该方法的有效性、准确性和鲁棒性。

Short Duration Power Quality Disturbance Signal Detection Method Based on Two Dimensional Discrete Static Wavelet Transform

On the basis of two-dimensional discrete static wavelet transform, a method that can accurately determine the start/stop moment of short duration power quality disturbance is proposed. By means of two-dimensional wavelet transform, the disturbance signal is decomposed in three different high-frequency directions and the start and stop moments of voltage sag that happens at the zero-cross point of fundamental frequency are accurately located by horizontal high-frequency coefficient; the start and stop moments of voltage sag that happens beside the zero-cross point of fundamental frequency are accurately located by the sum of vertical high-frequency coefficient and diagonal high-frequency coefficient. It is just needed for the proposed method to perform one-level wavelet transform by the simplest wavelet function db1. By means of software Matlab 6.5, the effectiveness, accuracy and robustness of the proposed method are verified by the simulation results.