希尔伯特变换与小波去噪提高暂态电能质量扰动检测与定位精度

在噪声污染严重情况下实现暂态电能质量扰动准确定位非常困难,该文提出了一种将希尔伯特-黄变换与小波去噪相结合的新方法来解决这一难题。该方法首先利用希尔伯特移相处理信号,获得含噪声的扰动信号包络,再利用小波去噪方法去除噪声信号,从而获得可准确定位扰动起止时刻的扰动信号,并通过扰动定位算法实现扰动起止时刻定位。算例表明,该方法在噪声较高的情况下可替代提升小波方法实现准确定位,通过比较,这种先提取、后去噪的方法比先去噪、后提取的方法定位精度高、稳定性好,该研究可为电力系统故障诊断及暂态保护提供参考。

Improving detection and location accuracy for transient power quality disturbance based on HHT and wavelet denoising

The paper presents a novel method which combines HHT-Hilbert Huang Transform with wavelet denoising to solve the difficulties for accurate locating of transient power quality disturbance in condition of severe noise pollution. The process of the method is that the signal is processed by applying Hilbert phase shifting to obtain a noised envelope of disturbing signal, and then the noise signal is removed by using wavelet denoising to get a disturbance signal with accurately located at start-stop time of the disturbance, and the accurate location of start-stop time of the disturbance can be obtained by disturbance localization algorithm. The simulation results show that this method can replace the lifting wavelet method to give an accurate location under severe noise condition. Compared with the method of extraction after denoising, it was concluded that the method of denoising after extraction has higher precision and better stability.