A SF6 decomposition product monitoring system based on infrared spectroscopy and its use method

Abstract

The present invention provides an SF6 decomposition product monitoring system based on infrared spectroscopy and a method for use thereof. The system includes a device to be tested, a gas collection module, a gas detection module, and a gas refill module. The gas collection module includes a gas collection chamber, a gas collection pipeline, a gas collection port, and a gas control assembly. The gas collection port is disposed at the gas outlet of the device to be tested. One end of the gas collection pipeline is connected to the gas outlet and the other end is connected to the gas collection chamber. The gas detection module includes a detector assembly, an infrared spectrum detection assembly, and an information processor. The detector assembly is disposed in the gas collection chamber. The infrared spectrum detection assembly is disposed at the outlet of the gas collection chamber and inputs collected data into the information processor. The gas refill module connects the gas collection chamber and the gas refill port of the device to be tested. The present invention has low cost, high detection efficiency, excellent detection accuracy, and can achieve continuous on-site monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas detection, and in particular relates to a SF6 decomposition product monitoring system based on infrared spectroscopy and a use method thereof. Background Art

[0002] Sulfur hexafluoride (SF6) gas is widely used in various gas-insulated electrical equipment due to its excellent insulation and arc-extinguishing properties. However, insulation defects left during the manufacturing and installation process, such as installation scratches, fixing protrusions, and metal powder residue, can cause partial discharge (PD) within the equipment, accelerating insulation degradation and potentially leading to equipment failure. SF6 gas, under varying discharge conditions and temperatures, produces low-fluorinated sulfides such as SF2, SF3, and SF4. However, trace amounts of water, oxygen, and other impurities are inevitably present in industrial equipment. These trace amounts of water and oxygen produce free radicals that react with these low-fluorinated sulfides to produce acidic substances such as SO2, H2S, and HF, as well as toxic substances such as SF4, SOF2, SF2, and SO2F2. Since common insulation equipment often has complex internal structures, troubleshooting after a failure is challenging. Therefore, continuous monitoring of SF6 decomposition products to identify potential faults early is crucial.

[0003] Experiments have shown that corona discharge significantly increases the concentration of SO2F2 in the gas mixture. The discharge time and SO2F2 concentration in the gas mixture exhibit a linear relationship, with SO2F2 concentration gradually increasing with longer discharge time. Sulfuryl fluoride (SO2F2) is a key characteristic component produced by the decomposition of SF6 during partial discharge. Detecting and analyzing its concentration using infrared spectroscopy can provide a basis for assessing the insulation condition of equipment, thereby preventing the significant economic losses caused by severe insulation damage due to long-term partial discharge.

[0004] A large number of experimental studies have shown that the ratio of SO2, SOF2 and SO2F2 produced by the decomposition of sulfur hexafluoride is highly correlated with the discharge degree of electrical equipment. The greater the discharge intensity, the greater the volume fraction of SO2F2 produced.

[0005] Currently, there are few analytical methods for SO₂F₂, the decomposition product of sulfur hexafluoride, reported domestically and internationally. Gas chromatography and mass spectrometry are commonly used. Gas chromatography, with its advantages of multi-component detection, high sensitivity, and accurate quantification, is currently the most widely used method for detecting decomposition components of sulfur hexafluoride. This method can simultaneously detect gas components such as CF₄, SO₂F₂, SOF₂, and SO₂. However, current gas chromatography technology requires gas collection and laboratory testing, and currently lacks on-site or online detection applications. Consequently, detection efficiency is low and costs are high. Mass spectrometry, on the other hand, is expensive and complex to operate, making on-site and online monitoring difficult. Summary of the Invention

[0006] The purpose of the present invention is to address the shortcomings of the existing technology and provide an SF6 decomposition product monitoring system and method based on infrared spectroscopy for online monitoring of sulfuryl fluoride SO2F2, a decomposition product of insulating gas SF6, which has low cost, high detection efficiency, excellent detection accuracy, and can realize on-site continuous monitoring.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A SF6 decomposition product monitoring system based on infrared spectroscopy includes a device to be tested, a gas collection module, a gas detection module and a gas refill module. The device to be tested is filled with insulating gas SF6. The gas collection module includes a gas collection chamber, a gas collection pipeline, a gas collection port and a gas control component. The gas collection port is arranged at the gas outlet end of the device to be tested. One end of the gas collection pipeline is connected to the gas outlet end and the other end is connected to the gas collection chamber. The gas control component is arranged on the gas collection pipeline. The gas detection module includes a detector component, an infrared spectrum detection component and an information processor. The detector component is arranged in the gas collection chamber. The infrared spectrum detection component is arranged at the outlet end of the gas collection chamber and inputs the collected data to the information processor. The gas refill module connects the gas collection chamber and the gas refill port of the device to be tested.

[0009] Furthermore, the infrared spectrum detection assembly includes a radiation source, a gas test tube, a filter wheel, and an infrared spectrum detection device. The gas test tube passes the gas to be detected collected in the gas collection chamber into the infrared spectrum detection device. The gas test tube is provided with a pressurizing device connected thereto. The filter wheel is provided at the gas inlet of the infrared spectrum detection device. Infrared light emitted by the radiation source enters the infrared spectrum detection device through the gas test tube and the filter wheel. The infrared spectrum detection device includes a housing, an incident slit, a collimating mirror, a micromirror element, a diffraction grating, a spherical mirror, and an exit slit. The radiation source is provided in front of the incident slit, the collimating mirror is provided on the same side as the exit slit, the micromirror element and the spherical mirror are provided on the same side as the incident slit, a detector element is provided behind the exit slit, and the micromirror element is rotatably provided. The infrared spectrum detection assembly and the information processor are connected via an optical fiber. The collimating mirror is a spherical collimating mirror. The gas test tube is made of high-pressure-resistant glass. The provision of a pressurizing device can increase pressure, thereby improving gas detection sensitivity. By using infrared spectroscopy technology to detect and analyze sulfuryl fluoride SO2F2 in the decomposition products of insulating gas SF6, the concentration of sulfuryl fluoride SO2F2 in the decomposition products can be measured in real time and accurately, which facilitates the timely identification of early latent faults in gas-insulated electrical equipment and avoids economic losses caused by serious faults. Compared with the current gas chromatography and mass spectrometry methods, this system uses less equipment, is easy to move and carry, and the equipment is easy to obtain, which reduces the monitoring cost and can realize synchronous online monitoring and real-time upload of concentration content.

[0010] Furthermore, the micromirror element is a MEMS oscillating mirror that performs sinusoidal motion. Preferably, the MEMS oscillating mirror is designed for mechanical robustness and manufactured using bulk silicon technology. Its large surface area allows for high optical throughput, and it performs sinusoidal motion with high mechanical precision, resulting in high stability of the wavelength axis. The single-crystal silicon therein ensures long-life, wear-free operation even under harsh environmental conditions. The MEMS oscillating mirror has the advantages of being light weight, small size, easy to mass-produce, and low in production cost, making the entire system more intuitive and simple, enabling on-site monitoring and real-time monitoring of the insulating gas composition within the equipment to identify potential faults early and avoid serious losses. The wavelength interval can be selectively limited to the practical range through appropriate parameterization of the MEMS oscillating mirror amplitude, thereby achieving longer signal averaging by extending the retention time.

[0011] Furthermore, the detector element includes a pyroelectric detector and a photodetector. A two-stage cooled mercury cadmium zinc telluride (MCZT) sensor is used as the pyroelectric detector, with different cutoff wavelengths. Its housing is slightly larger than the two-stage cooled indium gallium arsenide (InGaAs) detector implemented in the NIR assembly. The pyroelectric detector's cooling is achieved through the infrared spectrum detection device's housing. The nominal cooling target for the pyroelectric detector is preferably -10°C.

[0012] Furthermore, the housing is made of aluminum, which is inexpensive, lightweight, and corrosion-resistant, making it easier for the entire system to implement on-site online monitoring and upload detection data in real time, saving manufacturing costs and being economical and practical.

[0013] Furthermore, the radiation source includes a Kanthal incandescent lamp emitter for providing infrared radiation and a metal reflector for focusing the radiation source. The Kanthal incandescent lamp emitter can operate at temperatures up to 1275°C (1548K). The metal reflector is used to focus the radiation source directly onto the entrance slit of the infrared spectrum detection device, thereby achieving optimal radiation coupling.

[0014] Furthermore, the detector assembly includes a pressure detector and a temperature detector. Preferably, the temperature detector has a detection range of 298K to 348K. The temperature and pressure of the gas in the gas collection chamber are detected by the temperature and pressure detector to prevent overheating or overpressure from adversely affecting the entire detection system.

[0015] Furthermore, the gas control assembly includes a pressure regulating valve, a flow meter, an air pump, a first vacuum isolation valve, and a second vacuum isolation valve. The air pump is connected to the gas collection chamber and controls the direction of movement of gas decomposition products therein. The first vacuum isolation valve is disposed in the gas collection pipeline, and the second vacuum isolation valve is disposed between the air pump and the gas collection chamber. The pressure regulating valve receives signals from the industrial automation control system to drive the valve, changing the cross-sectional area between the valve core and the valve seat to control the gas flow input to the entire system, achieving automated regulation. The air pump pumps the insulating gas decomposition products from the device under test into the gas collection chamber. After testing, it also refills the remaining gas in the gas collection chamber back into the device under test, achieving gas circulation testing.

[0016] Furthermore, the gas refill module includes a gas refill line and a third vacuum isolation valve. The gas refill line connects the gas collection chamber and the gas refill port at both ends, respectively. The third vacuum isolation valve is located in the gas refill line. After testing, the gas refill module refills the remaining gas in the gas collection chamber back into the device under test, rather than directly discharging it into the atmosphere. This enables gas recycling testing, avoids environmental pollution, and is environmentally friendly.

[0017] The present invention also provides a method for using the SF6 decomposition product monitoring system based on infrared spectroscopy, comprising the following steps:

[0018] S1, start the infrared spectrum detection component;

[0019] S2. Using the gas control component, the gas to be tested in the device to be tested is introduced into the gas collection chamber through the gas collection port;

[0020] S3, performing spectral measurement on the gas collected in the gas collection chamber using an infrared spectrum detection component;

[0021] S4. Uploading the results of the infrared spectrum detection component to the information processor in real time, and analyzing the concentration of sulfuryl fluoride gas SO2F2 in the decomposition products of the insulating gas SF6;

[0022] S5. After the analysis is completed, the excess gas is refilled into the device under test through the gas refill module and the gas refill port.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention realizes online monitoring of sulfuryl fluoride SO2F2, a decomposition product of insulating gas SF6, based on infrared spectroscopy technology. It has low cost, high detection efficiency, excellent detection accuracy, and can realize on-site continuous monitoring. Infrared spectroscopy is used to detect and analyze the sulfuryl fluoride SO2F2 decomposition product of insulating gas SF6, and the concentration of sulfuryl fluoride SO2F2 in the decomposition product can be measured in real time and accurately. The detection sensitivity is high and the resolution is high, which ensures the detection accuracy and quality. Compared with gas chromatography and mass spectrometry, it is smaller in size, involves fewer detection components, is flexible and convenient to use, and is easy to realize on-site synchronous online detection. The concentration of sulfuryl fluoride SO2F2 is uploaded to the information processor in real time, which can quickly check the latent faults of the equipment in the early stage to avoid causing greater economic losses. The detection efficiency is high, and the equipment required for the entire system is easy to obtain and low in cost, which has the advantage of low cost. After the gas in the device to be tested enters the gas collection chamber, the gas detection module monitors the sulfuryl fluoride SO2F2 gas concentration therein in real time. The remaining gas after the detection is completed is filled back into the device to be tested through the gas refilling device, realizing the circulation detection of the gas, avoiding directly discharging it into the atmosphere to pollute the air, and being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the monitoring system of the present invention.

[0026] Figure 2 This is a schematic diagram of the internal structure of the infrared spectrum detection device of the present invention.

[0027] Figure 3 Schematic diagram of the radiation source position of the present invention.

[0028] Among them, 1-device to be tested, 2-pressure regulating valve, 3-flow meter, 4-air pump, 5-gas collection chamber, 6-infrared spectrum detection device, 61-incident slit, 62-collimating mirror, 63-MEMS oscillation mirror, 64-diffraction grating, 65-spherical mirror, 66-exit slit, 67-metal reflector, 7-information processor, 8-pressure detector, 9-temperature detector, 10-gas collection port, 11-gas refill port, 12-first vacuum isolation valve, 13-second vacuum isolation valve, 14-third vacuum isolation valve, 15-gas test tube, 16-filter wheel, 17-pressurizing device, 18-radiation source, 19-gas inlet. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0031] The present invention will be further described below with reference to specific examples, but they are not intended to limit the present invention.

[0032] The SF6 decomposition product monitoring system based on infrared spectroscopy shown in the figure includes a device to be tested 1, a gas collection module, a gas detection module and a gas refill module. The device to be tested 1 is filled with insulating gas SF6 to be detected. The gas collection module includes a gas collection chamber 5, a gas collection pipeline, a gas collection port 10 and a gas control component. The gas collection port 10 is arranged at the gas outlet end of the device to be tested 1. One end of the gas collection pipeline is connected to the gas outlet end, and the other end is connected to the gas collection chamber 5. The gas control component is arranged on the gas collection pipeline. The gas detection module includes a detector component, an infrared spectrum detection component and an information processor 7. The detector component is arranged in the gas collection chamber 5. The infrared spectrum detection component is arranged at the outlet end of the gas collection chamber 5 and inputs the collected data into the information processor 7. The gas refill module connects the gas collection chamber 5 and the gas refill port 11 of the device to be tested 1. Infrared spectroscopy technology is used to detect and analyze the decomposition product sulfuryl fluoride SO2F2 in the insulating gas SF6, and the concentration of sulfuryl fluoride SO2F2 in the decomposition product can be measured in real time and accurately. The detection sensitivity is high and the resolution is high, which ensures the detection accuracy and quality. Compared with gas chromatography and mass spectrometry, it is smaller in size, involves fewer detection components, is flexible and convenient to use, and is easy to realize on-site synchronous online detection. The concentration of sulfuryl fluoride SO2F2 is uploaded to the information processor in real time, which can quickly check the latent faults of the equipment in the early stage to avoid causing greater economic losses. The detection efficiency is high, and the equipment required for the entire system is easy to obtain and low in cost, which has the advantage of low cost. After the gas in the device to be tested enters the gas collection chamber, the gas detection module monitors the sulfuryl fluoride SO2F2 gas concentration therein in real time. The remaining gas after the detection is completed is filled back into the device to be tested through the gas refilling device, realizing the circulation detection of the gas, avoiding directly discharging it into the atmosphere to pollute the air, and being green and environmentally friendly. The present invention realizes online monitoring of sulfuryl fluoride SO2F2, a decomposition product of insulating gas SF6, based on infrared spectroscopy technology. It has low cost, high detection efficiency, excellent detection accuracy, and can realize on-site continuous monitoring.

[0033] Preferably, the infrared spectrum detection assembly includes a radiation source 18, a gas test tube 15, a filter wheel 16 and an infrared spectrum detection device 6. The gas test tube 15 passes the gas to be detected collected in the gas collection chamber 5 into the infrared spectrum detection device 6. The gas test tube 15 is provided with a pressurizing device 17 connected thereto. The filter wheel 16 is provided at the gas inlet of the infrared spectrum detection device 6. The infrared light emitted by the radiation source 18 enters the infrared spectrum detection device 6 through the gas test tube 15 and the filter wheel 16. The infrared spectrum detection device 6 includes a housing, an incident slit 6 1. Collimator 62, micromirror element, diffraction grating 64, spherical mirror 65, and exit slit 66. The radiation source 18 is arranged in front of the incident slit 61. The collimator 62 and exit slit 66 are arranged on the same side. The micromirror element and spherical mirror 65 are arranged on the same side as the incident slit 61. A detector element is arranged on the rear side of the exit slit 66. The micromirror element is rotatably arranged. The infrared spectrum detection component and the information processor 7 are connected via an optical fiber. The collimator 62 is a spherical collimator. The gas test tube 15 is made of high-pressure resistant glass and is provided with a gas inlet 19. The provision of a pressurizing device can increase the pressure in the gas detection module, thereby improving the gas detection sensitivity. By using infrared spectroscopy technology to detect and analyze sulfuryl fluoride SO2F2, the decomposition product of insulating gas SF6, the concentration of sulfuryl fluoride SO2F2 in the decomposition product can be measured in real time and accurately, which facilitates the timely identification of early latent faults of gas-insulated electrical equipment and avoids economic losses caused by serious faults. Compared with the current gas chromatography and mass spectrometry methods, this system uses less equipment, is easy to move and carry, and the equipment is easy to obtain, which reduces the monitoring cost and can realize synchronous online monitoring and real-time upload of concentration content.

[0034] Preferably, the micromirror element is a MEMS oscillating mirror 63, which performs sinusoidal motion. MEMS oscillating mirrors have the advantages of being light weight, small size, easy to mass-produce, and having low production costs, making the entire system more intuitive and simple, enabling on-site monitoring and real-time monitoring of the insulating gas composition within the equipment to identify potential faults early and avoid serious losses. The infrared spectrum detection device developed using the MEMS oscillating mirror has the characteristics of a wide spectral range, high resolution, and a high signal-to-noise ratio, which greatly reduces the interference of other characteristic gases on the detection and improves the accuracy of the detection. The wavelength interval can be selectively limited to the actual use range by appropriately parameterizing the MEMS oscillating mirror amplitude, so as to achieve longer signal averaging by extending the retention time.

[0035] Preferably, the detector element includes a pyroelectric detector and a photodetector. A two-stage cooled mercury cadmium zinc telluride (MCZT) sensor is used as the pyroelectric detector, with different cutoff wavelengths. Its housing is slightly larger than the two-stage cooled indium gallium arsenide (InGaAs) detector used in the NIR assembly. The pyroelectric detector's cooling is achieved through the infrared spectrum detection device's housing. The nominal cooling target for the pyroelectric detector is preferably -10°C.

[0036] Preferably, the housing is made of aluminum, which is inexpensive, lightweight, and corrosion-resistant, making it easier for the entire system to implement on-site online monitoring and upload detection data in real time, saving manufacturing costs and being economical and practical.

[0037] Preferably, the radiation source 18 comprises a Kanthal incandescent lamp emitter for providing infrared radiation and a metal reflector 67 for focusing the radiation source. The Kanthal incandescent lamp emitter can operate at temperatures up to 1275°C (1548K), and the metal reflector is used to focus the radiation source directly onto the entrance slit of the infrared spectrum detection device, thereby achieving optimal radiation coupling.

[0038] Preferably, the detector assembly includes a pressure detector 8 and a temperature detector 9. The detection range of the temperature detector is preferably 298 K to 348 K. The temperature and pressure of the gas in the gas collection chamber are detected by the temperature detector and the pressure detector to prevent overheating or overpressure from adversely affecting the entire detection system.

[0039] Preferably, the gas control assembly includes a pressure regulating valve 2, a flow meter 3, an air pump 4, a first vacuum isolation valve 12, and a second vacuum isolation valve 13. The air pump 4 is connected to the gas collection chamber 5 and controls the direction of movement of the gas decomposition products therein. The first vacuum isolation valve 12 is arranged in the gas collection pipeline, and the second vacuum isolation valve 13 is arranged between the air pump 4 and the gas collection chamber 5. The pressure regulating valve receives a signal from the industrial automation control system to drive the valve to change the cross-sectional area between the valve core and the valve seat to control the gas flow input to the entire system and realize automatic regulation. On the one hand, the air pump pumps the decomposition products of the insulating gas in the device under test into the gas collection chamber. On the other hand, after the test is completed, the remaining gas in the gas collection chamber is refilled into the device under test, realizing gas circulation detection.

[0040] Preferably, the gas refill module includes a gas refill line and a third vacuum isolation valve 14, with the two ends of the gas refill line connecting the gas collection chamber 5 and the gas refill port 11, respectively. Third vacuum isolation valve 14 is disposed in the gas refill line. After testing, the gas refill module refills the remaining gas in the gas collection chamber back into the device under test, rather than directly discharging it into the atmosphere. This enables gas recycling testing, avoids environmental pollution, and promotes environmental friendliness.

[0041] The present invention also provides a method for using the SF6 decomposition product monitoring system based on infrared spectroscopy, comprising the following steps:

[0042] S1, start the infrared spectrum detection component;

[0043] S2, using the gas control component to pass the gas to be tested in the device to be tested 1 into the gas collection chamber 5 through the gas collection port 10;

[0044] S3, performing spectral measurement on the gas collected in the gas collection chamber 5 using an infrared spectrum detection component;

[0045] S4, uploading the results obtained by the infrared spectrum detection component to the information processor 7 in real time, and analyzing the concentration of sulfuryl fluoride gas SO2F2 in the decomposition products of the insulating gas SF6;

[0046] S5 , refilling the excess gas after the analysis into the device under test 1 through the gas refill module and the gas refill port 11 .

[0047] When infrared light of a certain frequency (energy) illuminates a molecule, if the vibrational frequency of a group within the molecule matches the frequency of the external infrared radiation, the light energy is transferred to the molecule through a change in the molecular dipole moment. This group absorbs the infrared light of a certain frequency, producing a vibrational transition. The absorption of infrared light by the molecule is recorded by an instrument to produce the sample's infrared absorption spectrum. The wavelength, intensity, and shape of the absorption peaks in the spectrum are used to identify the groups within the molecule and perform structural analysis. Infrared light emitted by the radiation source is focused onto an entrance slit by a metal reflector. After passing through the entrance slit, it strikes a spherical collimator, which demultiplexes the light and directs it to a diffraction grating. Spectral decomposition is achieved through dispersion, and the angle of incidence on the diffraction grating depends on the rotation of the MEMS oscillating mirror. Consequently, the radiation is diffracted in different ways. The resulting spectrum is directed through the spherical mirror toward the exit slit. The narrowband radiation is detected by a photodetector located directly behind the exit slit. The spectral acquisition time is 4 ms, given by the mirror resonance frequency of approximately 250 Hz. The dimensions of the infrared spectrum detection device without the measurement device are 140 x 90 x 70 mm. The diffraction grating and detector cover different wavelengths from 2.5 to 9.9 µm. Spectral resolution can be improved by reducing the slit width, and the wavelength interval can be selectively limited to the practical range by appropriately parameterizing the MEMS oscillating mirror amplitude, thereby achieving longer signal averaging by extending the retention time.

[0048] In addition to sulfuryl fluoride gas SO2F2 gas, there are other decomposition products in SF6 decomposition gas, such as H2S, HF, SO2, CO and other gases. However, simulation experiments show that in the 2700~2800 cm^(-1) band, CO has no absorption, while SO2 and H2S have different degrees of spectral absorption. At the wave number of 2763 cm^(-1), the absorbance of SO2F2 is 0.2, and the absorption intensities of SO2 and H2S are 3.62×10 -4 With 2.44×10 -4 There is a certain gap in the magnitude of the absorption intensity between SO2F2 gas and SO2 and H2S, and the cross-interference phenomenon can be ignored. Therefore, the wave number of 2763cm^(-1) is preferably selected as the characteristic absorption line for the study of the infrared absorption characteristics of SO2F2 gas. By combining a diffraction grating, a spherical collimator, and a MEMS oscillating mirror, and optimizing the optical path, it has better optical performance, less stray light, and a high signal-to-noise ratio, making the overall structure compact, with high space utilization and low manufacturing cost. Different detectors, diffraction gratings, and customary line numbers can lead to different implementation variables. By setting the parameters of the infrared spectrum detection device itself, its wavelength detection area can be changed to realize the detection of the concentration of SO2F2. In addition to detecting the concentration of SO2F2 in insulating equipment, it can also detect the concentration of SF6 and the concentration of other SF6 decomposition products that can be detected by infrared within different wavelength ranges, realizing applications in multiple scenarios. By analyzing and calculating the difference in the infrared absorption spectrum at a wave number of 2763 cm^(-1) before and after gas injection, the concentration of sulfuryl fluoride SO2F2, a decomposition product of the insulating gas SF6, can be analyzed and measured.

[0049] After the absorption intensity of the gas is detected by the infrared spectrum detection device, the relationship between the sulfuryl fluoride gas concentration x and the absorbance y can be used:

[0050] y=0.000782x+0.02353

[0051] The sulfuryl fluoride gas concentration in the gas being tested is determined. The relationship between sulfuryl fluoride (SO₂F₂) concentration and discharge intensity is used to determine whether the equipment is operating normally. The online SO₂F₂ gas concentration is compared with the actual SO₂F₂ gas concentration that is expected to be present in the GIS equipment under normal conditions. A threshold is set. When the actual detected concentration exceeds the threshold, the information processor issues a warning, providing evidence of potential partial discharge (PD) faults in the GIS equipment, allowing for early scheduling of equipment maintenance and other operations.

[0052] When gas is backfilled in S5, the first vacuum isolation valve 12 is closed, and the second vacuum isolation valve 13 and the third vacuum isolation valve 14 are opened. The remaining gas in the gas collection chamber 5 is pressed back into the device to be tested 1 by the pressurization of the air pump 4. After the test is completed, the second vacuum isolation valve 13 and the third vacuum isolation valve 14 are automatically closed by the control system, and the first vacuum isolation valve 12 is opened to carry out a new round of gas detection.

[0053] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the present invention specification should be included in the protection scope of the present invention.

Claims

1. A SF6 decomposition product monitoring system based on infrared spectroscopy, characterized by: The invention comprises a device to be tested (1), a gas collection module, a gas detection module and a gas refilling module, wherein the device to be tested (1) is filled with insulating gas SF6 to be tested, the gas collection module comprises a gas collection chamber (5), a gas collection pipeline, a gas collection port (10) and a gas control component, the gas collection port (10) is arranged at the gas outlet end of the device to be tested (1), one end of the gas collection pipeline is connected to the gas outlet end, and the other end is connected to the gas collection chamber (5), the gas control component is arranged on the gas collection pipeline, the gas detection module comprises a detector component, an infrared spectrum detection component and an information processor (7), the detector component is arranged in the gas collection chamber (5), the infrared spectrum detection component is arranged at the outlet end of the gas collection chamber (5) and inputs the collected data to the information processor (7), the infrared spectrum detection component comprises a radiation source (18), a gas test tube (15), a filter wheel (16) and an infrared spectrum detection device (6), the gas test tube (15) passes the gas to be detected collected in the gas collection chamber (5) into the infrared spectrum detection device (6), the gas test tube (15) passes the gas to be detected collected in the gas collection chamber (5) into the infrared spectrum detection device (6), The tube (15) is provided with a pressurizing device (17) connected thereto, the filter wheel (16) is provided at the gas inlet of the infrared spectrum detection device (6), the infrared light emitted by the radiation source (18) enters the infrared spectrum detection device (6) through the gas test tube (15) and the filter wheel (16), the infrared spectrum detection device (6) comprises a housing, an incident slit (61), a collimating lens (62), a micromirror element, a diffraction grating (64), a spherical mirror (65) and an exit slit (66), the radiation source (18) is provided in front of the incident slit (61) The collimator (62) is arranged on the same side as the exit slit (66), the micromirror element and the spherical mirror (65) are arranged on the same side as the incident slit (61), a detector element is arranged on the rear side of the exit slit (66), the micromirror element is rotatably arranged, the infrared spectrum detection component and the information processor (7) are connected through an optical fiber, the collimator (62) is a spherical collimator, the gas test tube (15) is made of high-pressure resistant glass, and the gas refill module is connected to the gas collection chamber (5) and the gas refill port (11) of the device to be tested (1).

2. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The micromirror element is a MEMS oscillating mirror (63), and the MEMS oscillating mirror (63) performs sinusoidal motion.

3. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The detector elements include pyroelectric detectors and photodetectors.

4. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The shell is made of aluminum.

5. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The radiation source (18) comprises a Kanthal incandescent lamp emitter for providing infrared radiation and a metal reflector (67) for focusing the radiation source.

6. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The detector assembly includes a pressure detector (8) and a temperature detector (9).

7. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The gas control assembly comprises a pressure regulating valve (2), a flow meter (3), an air pump (4), a first vacuum isolation valve (12) and a second vacuum isolation valve (13); the air pump (4) is connected to a gas collection chamber (5) and controls the movement direction of gas decomposition products therein; the first vacuum isolation valve (12) is arranged in the gas collection pipeline, and the second vacuum isolation valve (13) is arranged between the air pump (4) and the gas collection chamber (5).

8. The SF6 decomposition product monitoring system based on infrared spectroscopy according to claim 1, characterized in that: The gas refill module comprises a gas refill pipeline and a third vacuum isolation valve (14), wherein both ends of the gas refill pipeline are connected to the gas collection chamber (5) and the gas refill port (11), respectively, and the third vacuum isolation valve (14) is arranged on the gas refill pipeline.

9. A method for using the SF6 decomposition product monitoring system based on infrared spectroscopy according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, start the infrared spectrum detection component; S2, using the gas control component to pass the gas to be tested in the device to be tested (1) into the gas collection chamber (5) through the gas collection port (10); S3, performing spectral measurement on the gas collected in the gas collection chamber (5) using an infrared spectrum detection component; S4, uploading the results obtained by the infrared spectrum detection component to the information processor (7) in real time, and analyzing to obtain the concentration of sulfuryl fluoride gas SO2F2 in the decomposition product of the insulating gas SF6; S5. After the analysis is completed, the excess gas is refilled into the device to be tested (1) through the gas refill module and the gas refill port (11).

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