| The actual electrical production put a high requirement for stability and safety evaluation.To meet the real-time detection need,this article carries out the research of a relevant on-line sensor.Based on the principle of ultraviolet fluorescence,the sensor quantitatively detects SO2 gas,which is the typical decomposition component of SF6 gas.This method has the characteristics of being free from electromagnetic interference,high detection accuracy,and portable devices.Therefore it is suitable for practical detection of electrical power site.Compared with other insulation detection methods,the method based on the decomposition components of SF6 gas has a better stable performance and much high detection sensitivity.Moreover,the application of optical detection of components can well overcome the time-consuming flaw of gas chromatography,and this makes the onine decomposition components detection comes true.As a typical decomposition product of SF6 gas during the discharge process,SO2 gas was written into Field Application Guide for SF6 Gas Decomposition Product Detection Technology in 2013,and it has become an important parameter for quantifying insulation status.Therefore,the sensing decices which has high selectivity and detection ability become the key to breakthrough.As the content of decomposition components is extremely low,improving the detection capability of equipment is really hard but extremelly important.Under this background,the quantitative detection of SF6 decomposed components SO2 was carried out in this paper.Based on the ultraviolet fluorescence method,the relevant research and innovative results are achieved as follows:(1)Set up a set of ultraviolet fluorescence detection platform,which is suitable for SF6 and its main decomposition products,and used standard gas to explore the measurement rule with this device.SO2 gas emits fluorescence under the excitation of ultraviolet light.The device uses a single photon counting probe to collect the fluorescence,and further converts it into a digital photon count to characterize the fluorescence intensity.The detection platform solves the problems of airtightness,light tightness,and time stability of the measurement.Studies have shown that at low concentrations,the concentration of SO2 gas is linear with its fluorescence intensity,for which the linearity is as high as 0.997.The detection limit is around 0.1?L/L,and the repeatability deviation is less than 12%.(2)By controlling the temperature and pressure during the measurement process,the influences of two major environmental factorsare were studied.And results show that the fluctuations of background counts with temperature and pressure are much less,while the fluorescence count is greatly affected by the two factors.Meanwhile,with the rise of temperature,the fluorescence counting characteristics of SO2 gas has a clear upward trend,and the influence of atmospheric pressure also keeps this trend.Based on this,this paper presents a related variable control solution to ensure the accuracy of the actual measurement process.(3)Based on the exsited SF6 gas discharge decomposition platform and SF6 actual equipment,and combined with gas chromatography-mass spectrometer,the measurement effect of ultroviolet fluorescence device was tested.The inspection process simulated a typical needle board defect discharge scenario,and the device is multi-checked for different discharge intensities within a complete discharge cycle.Comparing the measurement result of the ultroviolet fluorescence detection device with the measurement result of the gas chromatography-mass spectrometer,the deviation between the two is about 10%.Ultroviolet fluorescence device has a much smaller volume and a lower cost.It is more suitable for site testing,and is expected to achieve intelligent online monitoring of the power grid. |
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