基于EMD优化双谱的开关柜局部放电特高频信号时延计算方法研究

Time Delay Algorithm for UHF Partial Discharge Signals in Switchgear by EMD Based Improved Bispectrum Estimation Approach

局部放电特高频信号的时延估计是对开关柜放电缺陷进行精确定位的基础,提出了一种基于经验模分解优化双谱的开关柜局部放电特高频信号时延计算方法。首先根据实验室的开关柜尺寸,采用Xfdtd软件立开关柜的模型,对其进行特高频电磁波传播仿真计算,在不同检测点获取局部放电特高频信号。然后在实室搭建开关柜局部放电特高频检测试验平台,在不同位置获取局部放电特高频信号。最后针对局部放电特高仿真和实测信号,采用所提的改进双谱法以及现有3种常用方法对不同信号的时延进行计算。结果表明所提法更适用于实际开关柜局部放电缺陷的精确定位。

The time delay estimation of partial discharge(PD)ultra-high-frequency(UHF)signals is the basis for the accurate positioning of discharge defect in switchgear.This paper presents an improved bispectrum estimation approach based on empirical mode decomposition(EMD)to calculate the time delay of the PD UHF signals in the switchgear.Firstly,a simulation model of switch cabinet is established by Xfdtd software based on the size of the switchgear in laboratory,a calculation about the PD UHF electromagnetic wave propagation is made,and the PD UHF signals are obtained at different detection points.Then UHF test platform for the PD in the switchgear is built in the laboratory,and the PD UHF signals are obtained at different locations.Finally,the improved bispectrum method and three existing methods are used to calculate the time delay of PD UHF signals from simulation and actual measurement.The results show that the EMD based improved bispectrum can provide the precise positioning of the discharge defect in the switchgear.