Research On SF₆ Concentration Detection Method Based On Differential Absorption Photoacoustic Spectroscopy

In recent years,sulfur hexafluoride?SF₆?gas has been widely used in circuit breakers,transformers,GIS and other high-voltage power equipment due to its excellent electrical insulation and strong arc extinguishing ability.However,sealed high-pressure equipment filled with SF₆ gas usually has a certain gas pressure.At the same time,SF₆ gas leakage often occurs due to equipment failure or equipment aging during long-term work.The leakage of SF₆ gas in high-voltage equipment will cause the equipment's arc extinction and insulation capacity to drop significantly,which will not only bring great safety hazards to the operation of the power system,but also may endanger the safety of workers'lives.Therefore,SF₆ gas leak detection is very important for the safe and stable operation of electrical equipment.This paper systematically studies the basic theory of photoacoustic spectroscopy and differential absorption photoacoustic spectroscopy,the design method of SF₆ high-precision detection system based on differential absorption photoacoustic spectroscopy,and the method of improving the measurement accuracy of SF₆ detection system in complex environmental factors,and introduces The effect of experimental verification.The main work content and results of the paper are as follows:1.The basic theory of gas photoacoustic spectroscopy is studied.Combining gas infrared absorption spectroscopy theory and SF₆ gas photoacoustic effect,the expression of SF₆ gas photoacoustic signal is derived.Aiming at the low accuracy of traditional photoacoustic spectrum detection and the inability to detect flowing SF₆ gas,a new type of differential absorption photoacoustic spectrum detection technology is proposed,and the expression of SF₆ gas photoacoustic signal generation under this method is derived,which provides SF₆ gas concentration calibration Technical Support.2.Aiming at the problems that the traditional SF₆ gas detection system cannot meet the requirements of high detection accuracy,stable operation,high cost performance,and simplicity and practicality,on the basis of analyzing the SF₆ absorption line diagram in the HITRAN molecular absorption spectrum database,combining the existing conditions and experimental needs Preferably,10.55?m is used as the spectral line for SF₆ gas photoacoustic spectrum detection,and ASB-IR-12K infrared thermal light source is used as the light source.A design scheme of double cavity non-resonant photoacoustic cavity using stainless steel is proposed.The high-sensitivity AS-B4015AL38RC-L50microphone is used to collect the weak photoacoustic signal and the corresponding signal processing circuit is designed for it.A photoacoustic detection system software for SF₆gas photoacoustic signal acquisition,analysis and storage based on LabVIEW was developed.The SF₆ photoacoustic spectrum detection platform was built and the experimental data was successfully collected.3.Aiming at the problems of low detection accuracy and slow response speed when the existing SF₆ detection technology changes in the detection environment,a SF₆photoacoustic detection method based on GA-BP neural network for temperature compensation is proposed,which can not only reduce the environment The effect of temperature on the detection accuracy,and can greatly improve the reaction speed while maintaining a high detection accuracy.Experimental results show that this method can effectively reduce the error caused by temperature during measurement and improve the measurement accuracy of the entire SF₆ detection system.