利用偏微分方程抑制局部放电信号中的白噪声干扰

Application of Partial Differential Equation to Suppress White-noise Interference in GIS PD Signals

借助偏微分方程(partial differential equation,PDE)在图像去噪中的平滑滤波原理,提出一种基于PDE的局部放电(partial discharge,PD)信号去噪方法。采用基于Gauss滤波核函数的一维热传导方程去噪模型,利用有限差分法对去噪模型进行数值解。讨论PDE运算迭代次数和噪声强度对去噪效果的影响,当噪声强度在一定范围内时,适度的运算迭代次数可以获得较好的去噪效果。通过对仿真PD信号和现场实测信号试验结果表明,该方法具有去噪后信号能量损失较小,信号边缘细节保留较好,且运算量较少等优点,比其他传统去噪方法更有利于真实PD信号的快速提取。

As white noise interference inevitably exists in gas insulated switchgear （GIS）partial discharge （PD） detection, the availab]e suppression methods are unsatisfactory. By studying on partial differential equation（PDE） with its application in picture de-noising, a new de-noising method based on PDE is proposed. PDE de-noising model based on Gauss core function is analyzed in detail, and its numerical solutions is solved by the finite difference method. Moreover, we discuss the impacts of noise intensity and iterations of PDE on de-noising effect by analyzing simulation and experiment. Finally, PDE de-noising method is used to suppress the white-noise in ultrahigh frequency PI3 signal which is got from GIS field. The de-noised results of field monitoring signal indicate that this method can suppress white-noise effectively, has less energy loss, and keep the edge of signal property. It is conducive to restore the PD signal.