基于双通道能量差的环网柜局放信号消噪方法

A denoising method for partial discharge signal of ring network cabinet based on dual-channel power level difference

利用放电声音信号检测环网柜的局部放电具有信息量丰富、能够准确反映放电故障等特点而得到广泛应用,但放电声音信号的有效检测是一个难点。双通道录音在消噪领域中具有独特的优势,能够有效消除非平稳噪声,根据现场测量噪声干扰多为远距离的非平稳噪声,而局放信号为近距离声源的特点,提出了一种基于双通道能量差(PLD)的环网柜放电信号消噪方法。仿真实验结果表明,相比基于谱减法和维纳滤波的单通道消噪方法,本文所提消噪方法在两种非平稳噪声下的信噪比分别平均高出了14.8 dB和9.1 dB,均方误差(1×10-4)分别平均减小了19.34和15.50,消噪效果优于单通道消噪算法,现场实验结果表明,环网柜放电声音波形明显被突出加强,能够有效去除周围环境中的非平稳噪声,从而保留有效放电信号,为环网柜的局放诊断提供有效的数据支撑。

The discharge sound signal has been widely utilized to detect the partial discharge of the ring network cabinet, which has the characteristics of rich information and can accurately reflect the discharge fault. However, the effective detection of the discharge sound signal is a difficult point. The two-channel recording has unique advantages in the field of noise cancellation, which can effectively eliminate non-stationary noise. According to the characteristics of long-distance non-stationary noise measured on-site, the main noise interference has long-distance non-stationary feature. But, the partial discharge signal is a short-distance sound source. The noise elimination method of the discharge signal of the ring main unit is based on the dual-channel energy difference(power level difference, PLD). Compared with the single-channel denoising method based on spectral subtraction and Wiener filtering, the simulation experiment results show that the signal-to-noise ratio of the proposed denoising method under the two non-stationary noises is 14.8 dB and 9.1 dB higher on average, respectively. The square errors(1×10-4) is reduced by 19.34 and 15.50 on average, respectively, and the denoising performance is better than that of the single-channel denoising algorithm. In the field experiment, the discharge sound waveform of the ring network cabinet is enhanced, which can effectively remove non-stationary noise of the surrounding environment. Thus, the effective discharge signal is retained, which can provide effective data support for the partial discharge diagnosis of the ring main unit.