Design of automatic image measuring system Research on dynamic and high-sensitive detection of SF6 discharge decomposition products by fluorescence-suppressed fiber-enhanced Raman spectroscopy
Analyzing the dynamic change of composition and concentration of SF6 discharge decomposition products is the key to SF6 Gas-Insulated Switchgear(GIS)state diagnosis.This paper proposed a dynam-ic and high-sensitive detection method based on fluorescence-suppressed Fiber-Enhanced Raman Spectros-copy(FERS).Firstly,a fluorescence-suppressed FERS gas detection system of SF6 discharge decompo-sition products is established.With a Synergistic Fluorescence Filtering method combining CCD digital noise filtering and iris noise reduction,the signal-to-noise ratio of the system is increased by 228.4%.Based on Allan variance analysis,the optimal integration time of the system is determined to be 220 s.Next,by analyzing standard mixed gas samples under 2 bar pressure and 220 s integration time,the char-acteristic Raman peaks for qualitative and quantitative analysis of SF6 discharge decomposition products SOF2,SO2F2,COS,CF4,SO2,CO2 and CO are determined,and the lower limits of detection are calcu-lated to be 1.95,1.78,0.83,2.41,0.93,2.51,6.69 ppm,respectively.Finally,by a 168-hour contin-uous partial discharge experiment in a reduced scale GIS model,the fluorescence-suppressed FERS gas detection system is proved capable of dynamic and high-sensitive detection of SF6 discharge decomposition products,and the deviation from gas chromatography result is within±5%.Experimental results demon-strate that the proposed detection method can provide technical support for the safe operation of GIS.
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