基于振动信号的GIS机械松动与局部放电诊断方法

Study of mechanical looseness and partial discharge diagnoses of GIS based on vibration signals

为诊断运行中气体绝缘组合电器(GIS)典型的机械松动与绝缘故障,搭建GIS故障模拟实验平台,模拟GIS的绝缘子松动、尖刺放电与悬浮颗粒物放电故障,采集不同故障形态下GIS振动加速度信号。利用改进集总平均经验模态分解(MEEMD)的方法对信号进行模态特征提取,将提取的模态特征进行希尔伯特黄变换(HHT),得到希尔伯特边际谱。通过比较边际谱中不同频率段振动信号能量大小,判别GIS发生机械松动或局部放电故障。再利用小波变换求得反映放电程度的放电因子,区别不同放电故障的特点。通过分析不同模拟实验下的实测数据,结果表明:上述方法能够对GIS进行故障诊断,反映局部放电程度并区分放电故障类型,为GIS的机械松动与绝缘故障诊断提供一种有用的方法与途径。

In order to diagnose the typical mechanical looseness and insulation fault of gas insulated switchgear(GIS)in operation,this paper sets up experimental platform to simulate insulator loosenesses,tip discharges and suspended particle discharge faults.Acceleration signals of GIS vibration in different fault patterns are collected.Then the Hilbert marginal spectrum can be obtained by analyzing vibration signal using virtue of Hilbert-Huang transformation(HHT)after the modified ensemble empirical mode decomposition(MEEMD).The mechanical looseness or partial discharge of GIS can be judged through the energy of signals in different frequency bands.The wavelet transform is applied to calculate discharge factors,which reflects the characteristics of different types of partial discharge fault.Results obtained by experimental data analysis indicate that,the above methods can distinguish the faults of GIS and reflect the characteristics of partial discharge faults effectively.Thus providing a useful method for diagnosis of mechanical looseness and insulation fault of GIS.