| Gas switch insulation equipment?GIS?is widely used in high voltage power network,which is the key equipment to ensure safe operation of power grid.When discharge or overheating occurs,the insulating gas SF6 and the organic insulating materials in the GIS device can be decomposed,and CO is one kind of those characteristics decomposition gases.CO concentration monitoring provides basis for analysis of running state and fault of GIS.It is of great significance to carry out research on field concentration detection technology of decomposition gas CO based on TDLAS technology.The characteristic gases and detection methods of decomposition gas of insulating gas SF6 and organic insulating materials in GIS are studied in this paper,and the role of CO concentration detection in running state and fault analysis of GIS is analyzed;the basic properties of CO absorption spectrum in line strength,line width and line style are studied,and the selection of CO sbsorption line and the scanning characteristics of tunable laser wavelength are discussed in detail;the detection technology based on absorption spectroscopy of CO concentration is studied;in order to meet the demand of CO on-site detection for SF6 decomposition gas in GIS,the design scheme of extracting sample gas is designed,and the system composition and signal detection technology are discussed.This paper studies both control and drive principle of laser,and on the basis of it we design both temperature control circuit and current drive circuit for DFB laser,then experimental studies on temperature control precision,current driver stability and long-term laser output stability are carried out.We design double-optical balanced detection circuit to improve detection sensitivity,which realizes differential amplification function between measurement channel and reference channel.A portable experimental system for CO concentration detection is set up,and experiment is carried out by different concentrations of CO gas,and the processing algorithm of the measurement spectral and the inversion results of the CO measurement concentration are studied. |
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