Research On Online Monitoring Technology Of SF₆ Gas Decomposition Product SO₂/CS₂ Gas In Electrical Insulation Equipment

With the rapid development of the national power industry,SF₆ gas is commonly used in electrical insulation equipment.It has unique insulation properties and efficient arc extinguishing performance.Since a large number of devices are used,the failure rate is gradually increasing.How to make early warning of faults has become a hot topic of current research.When electrical equipment discharge failure occurs,SF₆ gas is decomposed to produce a variety of gases and compounds occurs.The detection of gas derivatives is widely accepted as a new type of equipment failure detection method.However,complex derivatives have become the difficulty of detection.By analyzing the characteristics of diverse fault decomposition products,it was found that SO₂ gas can be used as a characteristic gas for arc discharge and spark discharge,while CS₂ gas is only generated when the basin insulator is discharged along the surface.By monitoring the content of gas derivatives,experiments can alert equipment failure at an early stage.Therefore,this paper monitors the content of fault decomposition characteristic gas SO₂and CS₂,and the results can provide data support for field equipment maintenance.This paper introduces the research status at home and abroad and the methods of gas monitoring for equipment fault characteristics,as well as the advantages,disadvantages and applications of each method.Based on the existing research methods,the experiment proposed performing the concentration inversion of the mixed gas of fault characteristic gas SO₂ and CS₂ based on ultraviolet differential absorption spectroscopy.Then,the basic principle of UV differential absorption spectroscopy was introduced and the experimental system was constructed.The experimental system consists of an optical path,gas distribution,equipment control,and data acquisition and analysis,and then the system equipment is selected.The experiment also introduces the principle of data processing algorithm,and uses the algorithm to analyze and deal with the data and compare the results.In the experiment,the moving least squares method was used to invert the concentration of CS₂ and SO₂ in the 195-210nm band,while the SO₂ in the 290-310nm band was inversed by Fourier transform filtering.The results show that in the experimental environment.Both single-component SO₂ gas and single-component CS₂ gas can achieve good inversion results.The maximum error of concentration inversion was 4.6%and 2.6%,and the results showed excellent stability and repeatability.Finally,since the absorption cross-section value of the SO₂ gas in the mixed gas absorption coincidence band is an order of magnitude smaller than that of the CS₂ gas,the presence of the SO₂ gas does not interfere much with the concentration inversion of the CS₂ gas.Considering that the mutual interference between the two gases of 195-310nm and 290-310nm is small,the experiment uses the sub-band inversion concentration of the mixed gas.The final results show that the inversion error of SO₂ gas is 5.1%when the mixed gas is inverted,and the inversion error of CS₂ gas is 6.1%.The inversion error increases with the continuous decrease of the monitoring concentration,but the inversion error of each component is within the allowable range,which meets the experimental requirements.