基于振动原理的GIS母线导电杆松动故障分析与诊断

Analysis and diagnosis of a GIS bus conductor loosening based on mechanical vibration

气体绝缘组合电器(GIS)长期工作在大电流强电动力环境下,受开关设备反复操作与长期机械振动影响,GIS设备的电气连接处易出现松动故障,导致GIS异常振动,甚至引发气室漏气与绝缘性故障。针对GIS母线导电杆松动故障,提出了基于振动检测的故障诊断方法。对正常运行与松动故障时的振动进行理论分析,建立126 kV振动检测实验平台,研究母线导电杆松动时振动信号特征。研究表明:正常运行时,GIS母线管外壳振动频率在1000 Hz以内,100 Hz是主要机械振动频率。母线导电杆松动时1000 Hz以上频率成分显著增加,并且故障越严重增加越明显。故可将故障时显著增加的1000~3000 Hz的频域能量E_(1-3 kHz)与1000 Hz内的频域能量E_(0-1 kHz)作为特征量,将其比值定义为松动故障系数γ,反映故障的严重程度。计算表明,γ>0.04母线导电杆松动故障,γ越大故障越严重,当γ≥0.1则松动较为严重。

Gas insulated switchgear often works under high current and strong electrical power and for long periods.In addition,repeated operation of the switchgear with long-term mechanical vibration of the equipment easily leads to the loosening of the fasteners at the electrical connections.This contributes to GIS abnormal vibration,or even air leakage and insulation failure.In this paper,a vibration detection method is adopted for the loosening failure of the GIS bus conductor.First,theoretical research on the vibration of the normal and loose fault is carried out.Then,a 126 kV vibration detection experimental platform is built to study the characteristics of the vibration signal when the bus conductor is loose.The results indicate that the vibration frequency of the GIS bus bar shell is within 1000 Hz,and 100 Hz is the main mechanical vibration frequency if the GIS works well.When a bus conductor failure occurs,the frequency component above 1000 Hz increases significantly in proportion to the severity of the failure.Therefore,the frequency domain energy which is significantly increased between 1000~3000 Hz and 0~1000 Hz can be defined as E_(1~3 kHz)and E_(0~1 kHz)and used as characteristic parameters.Finally,the ratio of E_(1~3 kHz)and E_(0~1 kHz)is defined as the loosening fault coefficientγto reflect the severity of the loosening fault.Calculations show that whenγ>0.04,the bus conductor loosening fault occurs,and the larger the value,the more serious the fault.Ifγ≥0.1,a serious loosening failure may occur.