脉冲进样便携式TOF MS现场检测SF_6电气设备中的分解产物

Pulse Sampling Portable TOF MS for in situ Detection of Decomposition Products in SF_6 Gas Insulated Equipment

SF_6分解产物是SF_6电气设备内部故障的重要标志物。本工作研制了一台便携式飞行时间质谱仪(TOF MS),可对多种SF_6气体分解产物进行现场快速准确定量,为SF_6电气设备的状态评估和故障诊断提供关键信息。该仪器采用脉冲进样系统,可以在SF_6电气设备不停电状态下直接将设备内的气体样品引入质谱电离区进行分析。脉冲进样的管道总体积为20mL,进样量低于1mL/min,完成单个样品检测的样品总消耗量低于35mL(已换算至常压),与上一代仪器相比减少了85%以上,该进样方式有效地消除了谱图的背景干扰。本工作研制的脉冲进样便携式TOF MS对SF_6典型放电特征产物SO_2F_2、SO_2、CS_2、CF_4的检测灵敏度均可达到5μL/L,现场实验结果表明,该仪器在SF_6电气设备的状态评估和故障诊断中表现良好,在电力行业内具有广阔的应用前景。

Decomposition products of sulfur hexafluoride（SF6）are essential markers of faults in SF6 gas insulated equipment.A portable time-of-flight mass spectrometer（TOF MS）was designed to achieve fast and accurate quantification of several decomposition products of SF6 in situ,so as to provide crucial information for condition assessment and fault diagnosis of SF6 gas insulated equipment.Characterized by apulse sampling design,gas samples in SF6 gas insulated equipment could be directly introduced into the TOF MS and analyzed without removal of the equipment from service.With a total volume of 20 mL of the pulse sampling pipeline and a sampling flow rateunder 1 mL/min,less than 35 mL（under 1 atm）gas sample was required per test,representing a reduction over 85%in sample consumption compared with previous TOF MS design.Additionally,the new pulse sampling design showed a cleaner background signal.The detection sensitivity for four typical decomposition products of SF6,i.e.SO2 F2,SO2,CS2,CF4,was determined to be 5μL/L or better.The performance of the portable TOF MS was evaluated in recent field work,confirming its value in condition assessment and fault diagnosis of SF6 gas insulated equipment and showing a broad application prospect in power industry.