基于小波和高阶PDE的电缆局部放电去噪研究

局部放电(PD)试验是检测电力电缆绝缘性能的重要手段,由于试验现场电磁环境比较复杂,提取所得的PD信号已被噪声淹没。为得到较为真实的PD信号,提出了一种基于小波变换和高阶偏微分方程(PDE)相结合的去噪方法。利用小波变换提供较好的局部放电信号预处理和后处理平台,对低频子信号进行四阶PDE迭代去噪,同时采用效果评价指数信噪比(SNR)作为迭代终止条件。将该方法的去噪效果与传统的小波阀值去噪效果进行了比较,经过计算和仿真分析表明,文中方法能够较好的保留信号边缘与细节,比传统小波阀值去噪具有更优越的去噪性能。

Research on denoising of cables partial discharge based onwavelet and high order PDE

Partial discharge(PD)test is an important means to detect the insulation performance of power cable.Be-cause the electromagnetic environment of the test site is complicated,the extracted PD signal is submerged by noise. In order to get a more real PD signal,this paper proposes a de-noising method based on wavelet transform and high or-der partial differential equation(PDE).It adopts wavelet transform to provide better pre-processing and post-process-ing platform of partial discharge signal,and utilizes the fourth-order PDE to iterate the low-frequency sub-signal.At the same time,the signal to noise ratio(SNR)is used as the iteration termination condition.The de-noising effect of this method is compared with the traditional wavelet threshold de-noising effect.Finally,the experimental and simula-tion results show that this method can suppress noise effectively and keep the property of edge and detail.It has better de-noising performance than traditional wavelet threshold de-noising method.