A system and method for detecting sf6 gas decomposition products based on spectroscopy

Abstract

The application discloses a system and method for detecting SF6 gas decomposition products based on a spectrum method, and the system comprises an SF6 gas and decomposition product collecting device, a gas sample pool, a high-purity argon gas bottle, a laser device, an argon gas collecting pool, a spectrum analysis and detection device and a gas recharging device; the SF6 gas and decomposition product collecting device, the high-purity argon gas bottle, the laser device, the argon gas collecting pool, the spectrum analysis and detection device and the gas recharging device are all connected with the gas sample pool; the gas sample pool is embedded with a one-side wideband total reflection mirror and a quartz window sheet, the wideband total reflection mirror is symmetrically provided with a first arc-shaped total reflection mirror and a second arc-shaped total reflection mirror which are perpendicular to the wideband total reflection mirror, and the quartz window sheet is opposite to the wideband total reflection mirror; and the spectrum analysis and detection device collects scattered light through the quartz window sheet. The application has high detection sensitivity, fast detection speed and can realize real-time online analysis and detection.

Description

Technical Field

[0001] This invention belongs to the field of gas spectral analysis and detection technology, and relates to a system and method for detecting SF6 gas decomposition products based on spectral methods. Background Technology

[0002] SF6 gas possesses excellent insulation and arc-quenching properties and has been widely used in gas-insulated equipment. SF6-filled electrical equipment boasts advantages such as compact structure, stable electrical performance, strong arc-quenching capability, and safe and reliable operation, and is now widely used in ultra-high voltage and extra-high voltage power systems. SF6 is widely used as an ultra-high voltage insulating medium, and accurate detection of SF6 decomposition products is necessary in multiple stages of power production. During the long-term operation of power equipment, internal discharge or overheating faults are inevitable. Accurate detection of abnormal gases inside SF6 electrical equipment and other power equipment is a crucial foundation for conducting equipment fault diagnosis and condition assessment.

[0003] When SF6 filling equipment experiences hidden dangers or malfunctions, partial discharge or overheating inside the equipment causes the SF6 gas to decompose and generate various decomposition products. Under the influence of partial discharge, the SF6 gas undergoes a decomposition reaction, generating a variety of complex gases. These gases further react with impurities such as trace amounts of water and oxygen inevitably present inside the electrical equipment, generating gases such as SO2F2, SOF2, SO2, HF, and H2S. If the equipment contains insulating and metallic materials, gases such as CO2, CF4, and CO may also be generated. Most of the decomposition products of SF6 are highly toxic and corrosive, posing a significant threat not only to the safe operation of electrical equipment but also to the safety of operation and maintenance personnel and the environment.

[0004] Compared with traditional electrical detection methods, qualitative and quantitative analysis of the decomposition products of SF6 gas generated in the reaction can infer potential insulation hazards or faults in electrical equipment, which is of great significance for ensuring the stable operation of equipment and power grid. Therefore, regular detection of SF6 gas and its decomposition products to confirm the state of SF6 gas has great significance and good engineering application value.

[0005] Currently, the main methods for detecting SF6 gas and its decomposition products include gas chromatography (GC) and electrochemical gas sensors. GC offers high sensitivity and can identify the components of complex gas mixtures; it is often coupled with mass spectrometry (MS). Patents with publication numbers CN111398484A, CN113985233A, and CN208420814U disclose schemes for detecting SF6 and its decomposition products based on GC. While these methods offer high sensitivity, they are limited by the working principle of the GC instrument, resulting in long detection times, susceptibility of column separation to environmental influences, complex operation, and high costs, making real-time online detection difficult. Electrochemical gas sensing offers advantages such as low cost, ease of production, small size, and real-time online monitoring. Patents with publication numbers CN110411987A, CN112034015A, and CN110688751A disclose methods for detecting SF6 decomposition products based on electrochemical gas sensors. However, current electrochemical gas sensors have low sensitivity, poor selectivity, and high operating temperature, making them unsuitable for accurately measuring the concentration of SF6 gas and its decomposition products in GIS equipment.

[0006] Patents with publication numbers CN112666084A, CN206161530U, CN206848174U, and CN213456663U disclose schemes for detecting SF6 gas decomposition products based on Raman spectroscopy. While these schemes can detect characteristic products of SF6 decomposition, they suffer from several problems. For example, CN112666084A requires significant computational resources, the Raman signal of the gas is extremely weak and difficult to measure, and it cannot detect SF6 and its decomposition products in real time within GIS systems. CN206161530U requires an expensive Raman spectrometer and a complex optical path design, and the Raman signal of the gas is also extremely weak and difficult to measure. CN206848174U also suffers from extremely weak Raman patterns of the gas, failing to effectively improve the scattering efficiency of the gas towards the laser, resulting in extremely noisy measurement data. Similarly, CN213456663U requires an expensive Raman spectrometer, cannot effectively improve the scattering efficiency of the gas towards the laser, and results in extremely noisy measurement data.

[0007] To accurately detect the composition of SF6 gas and its decomposition products in GIS equipment, it is necessary to develop equipment based on new principles that is highly sensitive, fast in detection, inexpensive, and capable of online detection of SF6 and its decomposition products, thereby solving the current industry pain point of accurate detection of SF6 gas and its decomposition products in the power industry. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a system and method for detecting SF6 gas decomposition products based on spectroscopy. By performing spectroscopic analysis of the scattering of SF6 and its decomposition products, electrical equipment faults can be quickly and accurately identified.

[0009] The present invention adopts the following technical solution.

[0010] Step 1: Argon collection cell (19) evacuates the air from the gas sample cell (7) and adds high-purity argon gas into the gas sample cell (7) using a high-purity argon gas cylinder (15).

[0011] Step 2: The laser device emits a laser, which enters the gas sample cell (7). The laser is reflected back and forth between the first arc-shaped total reflection mirror (9) and the second arc-shaped total reflection mirror (16) and is fully scattered by the high-purity argon gas. The scattered light is reflected by the broadband total reflection mirror (10).

[0012] Step 3: The spectroscopic detection device collects the scattered light reflected by the broadband total reflection mirror (10) through the scattered light acquisition port and performs spectroscopic analysis to obtain the spectroscopic information of the gas sample cell (7), which is used as the spectral baseline of the gas sample cell (7).

[0013] Step 4: Argon collection cell (19) evacuates the high-purity argon gas from the gas sample cell (7);

[0014] Step 5: The acquisition device collects SF6 gas and its decomposition products from the GIS equipment and injects SF6 gas and its decomposition products into the gas sample cell (7).

[0015] Step 6: The laser device emits a laser, which enters the gas sample cell (7). The laser is reflected back and forth between the first arc-shaped total reflection mirror (9) and the second arc-shaped total reflection mirror (16), and is fully scattered by SF6 and its decomposition product gas. The scattered light is reflected by the broadband total reflection mirror (10).

[0016] Step 7: The spectroscopic detection device collects the scattered light reflected by the broadband total reflection mirror (10) through the scattered light acquisition port and performs spectral analysis to obtain the spectroscopic information of the gas sample cell (7). The spectral baseline of the gas sample cell (7) is subtracted to obtain the spectroscopic information of SF6 and its decomposition product gas. The composition of SF6 and its decomposition product is determined by identifying the position of each spectral peak in the spectrum.

[0017] Step 8: The gas recovery device recharges the SF6 gas and its decomposition products in the gas sample cell (7) back into the GIS equipment.

[0018] The beneficial effects of this invention are compared with those of the prior art:

[0019] This invention directly extracts SF6 and its decomposition products from GIS equipment. By increasing the pressure in the sample cell, the external laser is reflected back and forth between the curved total internal reflection mirrors, greatly increasing the scattering of the laser by gas molecules and significantly improving the signal of the gas scattering spectrum. This enables rapid and accurate detection of SF6 gas and its decomposition product components in GIS equipment. Utilizing spectroscopic analysis of SF6 gas and its decomposition products, the detection sensitivity is high, the analysis and detection speed is fast, the equipment is compact, and the cost is low. There is no leakage of SF6 gas decomposition characteristic products throughout the process, achieving environmental protection and effectively reducing environmental pollution. The entire device is simple to operate, easy to install and carry, and can be applied in practical applications. By detecting the components of SF6 gas decomposition products, the type of latent fault in GIS equipment can be determined. It has the advantages of simple overall detection system structure, high detection sensitivity, fast detection speed, and real-time online analysis and detection, effectively solving the pain points in the industry. Attached Figure Description

[0020] Figure 1 This is a system structure diagram of the present invention for detecting SF6 gas decomposition products based on spectroscopic methods;

[0021] The attached figures are labeled as follows: 1. Sampling probe; 2. Gas drying and purification device; 3. First mechanical pump; 4. First solenoid valve; 5. Second mechanical pump; 6. Second solenoid valve; 7. Gas sample cell; 8. Pressure gauge; 9. First arc-shaped total reflection mirror; 10. Broadband total reflection mirror; 11. Laser collimating lens; 12. First optical fiber; 13. Laser; 14. Third solenoid valve; 15. High-purity argon cylinder; 16. Second arc-shaped total reflection mirror; 17. Fourth solenoid valve; 18. Third mechanical pump; 19. Argon gas collection cell; 20. Quartz window; 21. Optical collecting lens; 22. Second optical fiber; 23. Notch filter; 24. Third optical fiber; 25. Spectrometer; 26. CCD; 27. Computer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0023] like Figure 1As shown, Embodiment 1 of the present invention provides a system for detecting SF6 gas decomposition products based on spectroscopy. In a preferred but non-limiting embodiment of the present invention, the system includes an SF6 gas and its decomposition products collection device, a gas sample cell 7, a high-purity argon cylinder 15, a laser device, an argon collection cell 19, a spectral analysis and detection device, and a gas refilling device.

[0024] The SF6 gas and its decomposition products collection device, the high-purity argon cylinder 15, the laser device, the argon collection cell 19, the spectral analysis and detection device, and the gas refilling device are all connected to the gas sample cell 7.

[0025] More preferably, the SF6 gas and its decomposition products collection device includes a sampling probe 1, a gas drying and purification device 2, a first mechanical pump 3, and a first solenoid valve 4;

[0026] Furthermore, the GIS equipment, sampling probe 1, gas drying and purification device 2, first mechanical pump 3, first solenoid valve 4, and gas sample cell 7 are connected in sequence.

[0027] The high-purity argon cylinder 15 is connected to the gas sample cell 7 via the third solenoid valve 14;

[0028] Argon collection cell 19 is connected to gas sample cell 7 via fourth solenoid valve 17 and third mechanical pump 18.

[0029] A pressure gauge 8 is installed on the gas sample cell 7 to detect the pressure of the gas sample cell 7 in real time. The side of the gas sample cell 7 has four metal tube interfaces to realize the introduction and export of gas.

[0030] The gas sample cell 7 has a broadband total reflection mirror 10 embedded inside and a quartz window 20 with good light transmission embedded on the side. A first arc-shaped total reflection mirror 9 and a second arc-shaped total reflection mirror 16 perpendicular to the broadband total reflection mirror 10 are symmetrically arranged on both sides of the broadband total reflection mirror 10. The quartz window 20 is directly opposite the broadband total reflection mirror 10.

[0031] The gas sample cell 7 is made of 304 or 316 stainless steel and can withstand a gas pressure of 6MPa, enabling multiple reflections of the laser within the sample cell.

[0032] More preferably, the laser device includes a laser 13, which is connected to the gas sample cell 7 via a first optical fiber 12 and a laser collimating lens 11.

[0033] The laser generally uses visible light wavelengths, preferably 488 nm, 532 nm and 633 nm.

[0034] The laser collimating lens 11 is installed on the side of the gas sample cell 7. The angle between the collimating lens 11 and the side allows the emitted laser to pass through the center of the symmetrically arranged first arc-shaped total reflection mirror 9 and second arc-shaped total reflection mirror 16, and be reflected onto the first arc-shaped total reflection mirror 9 and the second arc-shaped total reflection mirror 16.

[0035] In summary, the gas sample cell 7 is internally fitted with a broadband total reflection mirror 10 and two symmetrical arc-shaped total reflection mirrors, and a laser collimating mirror 11, a quartz window, and a readable pressure gauge 8 are respectively installed on the side.

[0036] The spectral analysis and detection device collects scattered light through a quartz window 20.

[0037] More preferably, the spectral analysis and detection device includes an optical collecting lens 21, a second optical fiber 22, a notch filter 23, a third optical fiber 24, a spectrometer 25, a CCD 26, and a computer 27 connected in sequence.

[0038] Among them, the optical collecting lens 21 is directly opposite the quartz window 20.

[0039] The optical collecting lens 21 can be moved precisely. Specifically, the optical collecting lens (21) is fixed on a one-dimensional translation adjustment frame that can be precisely adjusted. The distance between the optical collecting lens 21 and the quartz window 20 of the gas sample cell 7 can be adjusted by moving the one-dimensional translation adjustment frame.

[0040] The notch filter 23 filters wavelengths that are consistent with the laser output wavelength, preferably notch filters with wavelengths of 488 nm, 532 nm and 633 nm.

[0041] The spectrometer 25 uses a grating with 600, 1200 or 1800 lines, preferably an 1800-line grating;

[0042] The CCD26 camera is a deep-cooled, ultra-sensitive InGaAs linear array.

[0043] The gas recovery device includes a second mechanical pump 5 and a second solenoid valve 6;

[0044] Furthermore, the GIS equipment, the second mechanical pump 5, the second solenoid valve 6, and the gas sample cell 7 are connected in sequence.

[0045] The gas recharge device is used to recharge the SF6 gas and its decomposition products after the laser has been fully scattered back into the GIS equipment, preventing the SF6 gas and its decomposition products from leaking to the outside.

[0046] The first, second, and third mechanical pumps mentioned above are all dry mechanical pumps, which can avoid the interference of mechanical pump oil with the gas being analyzed.

[0047] Components that communicate with the gas are connected by pipes, and components that connect to optical elements are connected by optical fibers.

[0048] The entire detection system has a simple structure, high detection sensitivity, and fast detection speed, enabling real-time online analysis and detection.

[0049] Embodiment 2 of the present invention provides a method for detecting SF6 gas decomposition products based on spectrometry, comprising the following steps:

[0050] Step 1: Argon collection cell 19 evacuates the air from the gas sample cell 7, and high-purity argon gas is added to the gas sample cell 7 from high-purity argon gas cylinder 15.

[0051] Open the fourth solenoid valve 17 and the third mechanical pump 18, and the argon collection cell 19 will evacuate the air from the gas sample cell 7.

[0052] Open the third solenoid valve 14 and add high-purity argon gas from the high-purity argon gas cylinder 15 into the gas sample cell 7. When the pressure gauge 8 reads 3MPa, close the third solenoid valve 14.

[0053] Step 2: The laser device emits a laser, which enters the gas sample cell 7. The laser is reflected back and forth between the first arc-shaped total reflection mirror 9 and the second arc-shaped total reflection mirror 16, and is fully scattered by the high-purity argon gas. The scattered light is reflected by the broadband total reflection mirror 10.

[0054] When the laser 13 is turned on, the laser light enters the gas sample cell 7 after passing through the first optical fiber 12 and the laser collimating lens 11. The laser light is reflected back and forth between the first arc-shaped total reflection mirror 9 and the second arc-shaped total reflection mirror 16 and is fully scattered by the high-purity argon gas. The scattered light is reflected by the broadband total reflection mirror 10.

[0055] Step 3: The spectral analysis and detection device collects the scattered light reflected by the broadband total reflection mirror 10 through the scattered light acquisition port and performs spectral analysis to obtain the spectral information of the gas sample cell 7, which is used as the spectral baseline of the gas sample cell 7.

[0056] Adjust the distance between the optical collecting lens 21 and the quartz window 20, and the optical collecting lens 21 collects the scattered light reflected by the broadband total reflection mirror 10;

[0057] After passing through the second optical fiber 22, notch filter 23 and third optical fiber 24, it enters the spectrometer 25 and CCD 26, and then enters the computer 27 for analysis, converting the analog signal into a digital signal, and finally displaying the spectroscopic information of the gas sample cell 7, which is used as a baseline.

[0058] Step 4: Argon collection cell 19 evacuates the high-purity argon gas from the gas sample cell 7;

[0059] Open the fourth solenoid valve 17 and the third mechanical pump 18 to discharge the high-purity argon gas in the gas sample cell into the argon gas collection cell;

[0060] Step 5: The acquisition device collects SF6 gas and its decomposition products from the GIS equipment and injects the SF6 gas and its decomposition products into the gas sample cell 7.

[0061] SF6 gas and its decomposition products are collected from the GIS system through sampling probe 1. After being purified by gas purifier 2, the first mechanical pump 3 and the first solenoid valve 4 are turned on to add SF6 and its decomposition products into the gas sample cell 7. The gas is released until the pressure gauge 8 reads 3 MPa, and then the first solenoid valve 4 is turned off. Theoretically, the higher the gas concentration, the stronger the scattering of light, the more obvious the spectral signal of the gas, and the higher the sensitivity of SF6 and its decomposition products detection. However, since the pressure resistance range of the sample chamber is 0.1-6 MPa, 3 MPa is preferable.

[0062] Step 6: The laser device emits a laser beam, which enters the gas sample cell 7. The laser beam is reflected back and forth between the first arc-shaped total reflection mirror 9 and the second arc-shaped total reflection mirror 16, and is fully scattered by SF6 and its decomposition product gas. The scattered light is reflected by the broadband total reflection mirror 10.

[0063] The laser 13 is turned on, allowing the laser light to pass through the first optical fiber 12, then through the laser collimating lens 11, and into the gas sample cell 7. The laser light is reflected back and forth between the first curved total reflection mirror 9 and the second curved total reflection mirror 16, and is fully scattered by SF6 and its decomposition product gases. The scattered light is reflected by the broadband total reflection mirror 10.

[0064] Step 7: The spectral analysis and detection device collects the scattered light reflected by the broadband total reflection mirror 10 through the scattered light acquisition port and performs spectral analysis to obtain the spectral information of the gas sample cell 7. The spectral baseline of the gas sample cell 7 is subtracted to obtain the spectral information of SF6 and its decomposition product gas. By identifying the position of each spectral peak in the gas spectrum, the composition of SF6 and its decomposition product is determined, and the type of substance is determined.

[0065] The distance between the optical collecting lens 21 and the quartz window 20 is adjusted. The optical collecting lens 21 collects the scattered light reflected by the broadband total reflection mirror 10. After passing through the second optical fiber 22, the notch filter 23 and the third optical fiber 24, the light enters the spectrometer 25 and CCD 65 and then enters the computer 27 for analysis. Then the spectral baseline of the gas sample cell 7 is subtracted, and finally the spectroscopic information of SF6 and its decomposition product gas is displayed.

[0066] Step 8: The gas recovery device recharges the SF6 gas and its decomposition products from the gas sample cell 7 back into the GIS equipment;

[0067] Finally, the second solenoid valve 6 and the second mechanical pump 5 are opened, and the SF6 gas and its decomposition products in the gas sample cell 7 are returned to the GIS equipment.

[0068] The beneficial effects of this invention are compared with those of the prior art:

[0069] This invention directly extracts SF6 and its decomposition products from GIS equipment and introduces them into a high-pressure sample cell. The high-pressure sample cell is designed with symmetrical arc-shaped total internal reflection mirrors, allowing laser light to reflect back and forth within these mirrors. This significantly increases the scattering of the laser light by gas molecules. Combined with pressure control within the gas sample cell, the signal of the scattered light spectrum is greatly enhanced. This invention can accurately and rapidly detect the components of SF6 gas and its decomposition products in GIS equipment. Utilizing the scattering spectroscopic information of SF6 gas and its decomposition products, it achieves high sensitivity, fast analysis and detection speed, compact equipment, and low cost. The entire process involves no leakage of characteristic SF6 decomposition products, thus protecting the environment and effectively reducing pollution. The entire device is simple to operate, easy to install and carry, and can be practically applied. By detecting the components of SF6 gas decomposition products, the type of latent fault in GIS equipment can be determined. It boasts advantages such as a simple overall detection system structure, high detection sensitivity, fast detection speed, and real-time online analysis and detection capabilities, effectively solving pain points in the industry.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A system for detecting SF6 gas decomposition products based on spectroscopy, comprising an SF6 gas and its decomposition products collection device, a gas sample cell (7), a high-purity argon cylinder (15), a laser device, an argon collection cell (19), a spectral analysis and detection device, and a gas refilling device; The SF6 gas and its decomposition products collection device, high-purity argon cylinder (15), laser device, argon collection cell (19), spectral analysis and detection device, and gas refill device are all connected to the gas sample cell (7); its features are: The gas sample cell (7) is embedded with a broadband total reflection mirror (10) and a quartz window (20). A first arc-shaped total reflection mirror (9) and a second arc-shaped total reflection mirror (16) perpendicular to the broadband total reflection mirror (10) are symmetrically arranged on both sides of the broadband total reflection mirror (10). The quartz window (20) faces the broadband total reflection mirror (10). The spectral analysis and detection device collects scattered light through a quartz window (20); The SF6 gas and its decomposition products collection device includes a sampling probe (1), a gas drying and purification device (2), a first mechanical pump (3), and a first solenoid valve (4). Furthermore, the GIS equipment, sampling probe (1), gas drying and purification device (2), first mechanical pump (3), first solenoid valve (4) and gas sample cell (7) are connected in sequence; The laser device includes a laser (13), which is connected to the gas sample cell (7) through a first optical fiber (12) and a laser collimating lens (11); The laser collimating lens (11) is installed on the side of the gas sample cell (7), so that the laser passes through the center of the symmetrically arranged first arc-shaped total reflection mirror (9) and second arc-shaped total reflection mirror (16) and is reflected onto the first arc-shaped total reflection mirror (9) and second arc-shaped total reflection mirror (16). The gas recharge device includes a second mechanical pump (5) and a second solenoid valve (6); The GIS equipment, the second mechanical pump (5), the second solenoid valve (6), and the gas sample cell (7) are connected in sequence.

2. The system for detecting SF6 gas decomposition products based on spectroscopic methods according to claim 1, characterized in that: The high-purity argon cylinder (15) is connected to the gas sample cell (7) via the third solenoid valve (14); Argon collection cell (19) is connected to gas sample cell (7) via fourth solenoid valve (17) and third mechanical pump (18).

3. The system for detecting SF6 gas decomposition products based on spectroscopic methods according to claim 1, characterized in that: A pressure gauge (8) is installed on the gas sample cell (7).

4. The system for detecting SF6 gas decomposition products based on spectrometry according to claim 1, characterized in that: The laser used is a visible light laser with a wavelength of 488 nanometers, 532 nanometers, or 633 nanometers.

5. The system for detecting SF6 gas decomposition products based on spectroscopic methods according to claim 1, characterized in that: The spectral analysis and detection device includes an optical collecting lens (21), a second optical fiber (22), a notch filter (23), a third optical fiber (24), a spectrometer (25), a CCD (26), and a computer (27) connected in sequence. Among them, the optical collecting lens (21) is directly opposite the quartz window (20).

6. The system for detecting SF6 gas decomposition products based on spectroscopic methods according to claim 5, characterized in that: The optical collecting lens (21) is fixed on a one-dimensional translation adjustment frame. The distance between the optical collecting lens (21) and the quartz window (20) of the gas sample cell (7) is adjusted by moving the one-dimensional translation adjustment frame. The wavelength filtered by the notch filter (23) is the same as the wavelength of the laser output by the laser. The spectrometer (25) uses an 1800-line grating; The CCD (26) camera is an InGaAs linear array.

7. A method for detecting SF6 gas decomposition products based on spectrometry, implemented using the system described in any one of claims 1-6, characterized in that: The method includes the following steps: Step 1: Argon collection cell (19) evacuates the air from the gas sample cell (7) and adds high-purity argon gas into the gas sample cell (7) using a high-purity argon gas cylinder (15). Step 2: The laser device emits a laser, which enters the gas sample cell (7). The laser is reflected back and forth between the first arc-shaped total reflection mirror (9) and the second arc-shaped total reflection mirror (16) and is fully scattered by the high-purity argon gas. The scattered light is reflected by the broadband total reflection mirror (10). Step 3: The spectral analysis and detection device collects the scattered light reflected by the broadband total reflection mirror (10) through the scattered light acquisition port and performs spectral analysis to obtain the spectral information of the gas sample cell (7), which is used as the spectral baseline of the gas sample cell (7). Step 4: Argon collection cell (19) evacuates the high-purity argon gas from the gas sample cell (7); Step 5: The acquisition device collects SF6 gas and its decomposition products from the GIS equipment and injects SF6 gas and its decomposition products into the gas sample cell (7). Step 6: The laser device emits a laser, which enters the gas sample cell (7). The laser is reflected back and forth between the first arc-shaped total reflection mirror (9) and the second arc-shaped total reflection mirror (16), and is fully scattered by SF6 and its decomposition product gas. The scattered light is reflected by the broadband total reflection mirror (10). Step 7: The spectral analysis and detection device collects the scattered light reflected by the broadband total reflection mirror (10) through the scattered light acquisition port and performs spectral analysis to obtain the spectral information of the gas sample cell (7). The spectral baseline of the gas sample cell (7) is subtracted to obtain the spectral information of SF6 and its decomposition product gas. The composition of SF6 and its decomposition product is determined by identifying the position of each spectral peak in the spectrum. Step 8: The gas refilling device refills the SF6 gas and its decomposition products in the gas sample cell (7) into the GIS equipment.

8. The method for detecting SF6 gas decomposition products based on spectrometry according to claim 7, characterized in that: The process of adding high-purity argon gas into the gas sample cell (7) in step 1 and injecting SF6 gas and its decomposition products into the gas sample cell (7) in step 5 is stopped when the gas pressure in the gas sample cell (7) reaches 3MPa.

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