Method and device for measuring SF6 gas decomposition products through multi-cavity resonance photoacoustic spectrometry

Abstract

The invention relates to the technical field of electrical equipment fault diagnosis and evaluation, and discloses a method and device for measuring SF6 decomposition product gas through a multi-cavity resonance photoacoustic spectrometry. The device comprises an infrared light source and a photoacoustic spectrum resonant cavity, the laser capable of being continuously tuned is used for emitting infrared light according to a set period after regulation and control and transmitting the emitted infrared light to the processing unit, the infrared light with the set wavelength is obtained through modulation of the processing unit, and the processing unit transmits the modulated infrared light to the photoacoustic spectrum resonant cavity; the photoacoustic spectrum resonant cavity comprises a buffer cavity and a plurality of resonant cavities which are arranged around the buffer cavity in a central symmetry manner; each resonant cavity is communicated with the buffer cavity to form a plurality of completely consistent T-shaped resonant cavities; according to the method and the device for measuring the SF6 gas decomposition products by the multi-cavity resonance photoacoustic spectrometry, the sensitivity of gas concentration detection can be improved, and the method and the device are suitable for measuring the decomposition products of multi-component gases such as SF6 and the like.

Description

Technical Field

[0001] The present invention relates to the field of electrical equipment fault diagnosis and evaluation, and in particular to multi-cavity resonance photoacoustic spectroscopy for measuring SF 6 Method and apparatus for decomposing product gases. Background Art

[0002] The photoacoustic cavity is used to continuously and stably amplify the sound signal and is the core component of the photoacoustic spectroscopy measurement. The microphone in the photoacoustic cavity converts the sound wave signal into a processable electrical signal. A properly designed resonance cavity can achieve photoacoustic resonance amplification, effectively suppress the background, and significantly improve the signal-to-noise ratio, so it is more practical. The traditional dumbbell-shaped (H-type) resonance cavity has buffer cavities at both ends and a resonance cavity in the middle. The light emitted by the light source needs to be collimated into a thin beam to pass through the resonance cavity. The optical path is relatively limited, and the detected gas molecules cannot fully and effectively interact with the incident light for photoacoustic effect. In addition, light sources with poor beam quality are easily intercepted by the walls of the resonance cavity, resulting in weak effective signals and large background noise.

[0003] Based on this, people proposed a T-type resonant cavity detection system, which allows the light beam to pass through a buffer cavity with a larger aperture and avoid entering a thin resonant cavity, thereby making full use of the energy of a light source with a larger divergence angle. However, a single T-type cavity cannot avoid the influence of airflow noise, resulting in excessive deviation in signal measurement. In gas component detection, spectral detection is widely used due to its fast speed and high accuracy. Traditional photoacoustic spectroscopy usually uses an infrared light source with a fixed wavelength, which cannot achieve multi-component gas testing; although the use of tunable infrared lasers can achieve multi-wavelength adjustment of infrared light, it is usually very expensive.

[0004] The existing spectrum detection technology can usually only detect the concentration of one gas at a time. 6 Various characteristic gas components in gas decomposition products, such as SO 2 F 2 、SO 2 F 4 、SOF 2 、SO 2 , HF, etc., must be measured in batches, which cannot achieve time consistency and reduces measurement efficiency and accuracy. 6 When detecting gas decomposition products on site, the gas flow in the instrument, complex environmental conditions and short infrared optical path will introduce a lot of noise interference. Therefore, in the process of gas detection, it is very important to reduce the environment and effectively increase the infrared optical path for signal measurement. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a method and device for measuring the decomposition products of SF6 gas by multi-cavity resonant photoacoustic spectroscopy. By setting up a plurality of completely identical T-shaped resonant cavities, interference factors such as environmental noise and airflow noise can be reduced, the sensitivity of gas concentration detection can be improved, and the method and device can be applied to the measurement of decomposition products of multi-component gases such as SF6.

[0006] The present invention adopts the following technical solution.

[0007] In a first aspect, the present invention provides a method for measuring SF using a multi-cavity resonance photoacoustic spectroscopy method. 6 The device for measuring gas decomposition products comprises: an infrared light source and a photoacoustic spectrum resonant cavity, wherein the infrared light source is a continuously tunable laser, the continuously tunable laser is connected to a processing unit, and is used to emit infrared light according to a set period after being regulated, and transmit the emitted infrared light to the processing unit, and the processing unit modulates the infrared light to obtain infrared light of a set wavelength, and the processing unit then transmits the modulated infrared light to the photoacoustic spectrum resonant cavity; the photoacoustic spectrum resonant cavity comprises: a buffer cavity and a plurality of resonant cavities centrally symmetrically arranged around the buffer cavity; each resonant cavity is connected to the buffer cavity to form a plurality of completely identical T-shaped resonant cavities; the buffer cavity is used to accommodate the SF to be measured 6 The resonant cavity cooperates with the buffer cavity to amplify the SF to be measured. 6 The gas absorbs infrared light to generate photoacoustic signals, which are processed and transmitted to a computer to calculate SF 6 Concentration of gaseous decomposition products.

[0008] Preferably, an infrared light reflecting unit is provided inside the buffer cavity; the infrared light reflecting unit comprises: a plurality of groups of arc-shaped infrared light total reflecting mirrors for receiving infrared light incident into the buffer cavity and reflecting the infrared light multiple times between the plurality of groups of arc-shaped infrared light total reflecting mirrors.

[0009] Preferably, an infrared window is provided at a position of the buffer cavity for receiving infrared light; an infrared optical fiber for transmitting infrared light to the buffer cavity is provided at the output end of the infrared light processing unit, an infrared collimator is provided at one end of the infrared optical fiber away from the infrared light processing unit, and the emitting end of the infrared collimator faces the infrared window.

[0010] Preferably, the processing unit is a plurality of groups of band-pass filters, one end of the plurality of groups of band-pass filters is connected to the continuously tunable laser, and the other end is connected to the infrared optical fiber.

[0011] Preferably, a microphone is provided inside each of the resonance cavities, and the microphone is used to collect the SF to be measured. 6 The gas absorbs infrared light to generate photoacoustic signals, which are then processed and transmitted to a computer.

[0012] Preferably, the device further comprises: a signal generator and a laser controller; the signal generator, the laser controller and the continuously tunable laser are connected in sequence to adjust the period of the continuously tunable laser emitting infrared light.

[0013] Preferably, the device also includes: a phase-locked amplifier and a data collector, the phase-locked amplifier is connected to the signal generator, the photoacoustic spectroscopy resonant cavity and the data collector; the phase-locked amplifier is used to control the signal generator and amplify the photoacoustic signal output by the photoacoustic spectroscopy resonant cavity; the data collector is used to collect and process the photoacoustic signal sent by the phase-locked amplifier and transmit it to a computer.

[0014] Preferably, the buffer cavity is in a cube shape, each resonance cavity is in a cylindrical shape, there are four resonance cavities, and the four resonance cavities are respectively arranged on the upper, lower, left and right surfaces of the buffer cavity, and the axis of the resonance cavity passes through the center of the buffer cavity.

[0015] Preferably, the buffer cavity is also provided with a passage for passing the SF to be tested. 6 A buffer cavity air inlet for the gas and a buffer cavity air outlet for collecting tail gas.

[0016] In a second aspect, the present invention provides a method for measuring SF using a multi-cavity resonance photoacoustic spectroscopy method. 6 A method for measuring gas decomposition products using the multi-cavity resonance photoacoustic spectroscopy method as claimed in claim 1 6 The device for producing gaseous decomposition products comprises the following steps:

[0017] Step 1: Place the SF to be tested 6 The gas is passed into the buffer cavity of the photoacoustic spectroscopy resonant cavity;

[0018] Step 2, modulating the period of the infrared light generated by the continuously tunable laser, and inputting the infrared light emitted by the continuously tunable laser into the processing unit for modulation processing to obtain infrared light with a set period and wavelength;

[0019] Step 3: The modulated infrared light enters the buffer cavity in the photoacoustic spectroscopy resonant cavity, and the SF to be measured located inside the buffer cavity 6 When the gas absorbs infrared light, it generates a photoacoustic signal;

[0020] Step 4: Use multiple resonant cavities to amplify the photoacoustic signal inside the buffer cavity, and transmit the photoacoustic signal to a computer, and use the computer to calculate and obtain the SF to be measured. 6 The concentration of gaseous decomposition products.

[0021] Preferably, obtaining the concentration of the decomposition products of the multi-component gas to be measured by computer operation and calculation includes the following steps:

[0022] Taking the average of the photoacoustic signals from the multiple resonant cavities by computer;

[0023] The mean value is operated and calculated to obtain the concentration of the decomposition products of the multi-component gas to be tested.

[0024] The beneficial effect of the present invention is that, compared with the prior art, the photoacoustic spectroscopy resonant cavity provided in the present invention includes a plurality of resonant cavities, and each resonant cavity can be combined with a buffer cavity to form a T-shaped resonant cavity, forming a plurality of completely identical T-shaped resonant cavities. Compared with the single T-shaped photoacoustic structure cavity in the prior art, the present invention can reduce interference factors such as environmental noise and airflow noise by providing a plurality of T-shaped resonant cavities and taking an average value of the measurement results, thereby improving the sensitivity of gas concentration detection. In addition, the infrared light source of the present invention adopts a continuously tunable laser, which can change the period of the output infrared light by electrical modulation, and modulate the infrared light emitted by the continuously tunable laser by a processing unit to obtain infrared light of a specific wavelength, and then input the infrared light modulated by the processing unit into the photoacoustic spectroscopy resonant cavity to analyze the trace gas concentration. By modulating the wavelength and period of the infrared light, the SF 6 The measurement requirements of different component concentrations in decomposition products. Compared with traditional tunable infrared lasers, the price is significantly reduced.

[0025] In order to further enhance the measurement effect, an infrared light reflection unit is also arranged inside the buffer cavity in the present invention. By reflecting the infrared light incident into the buffer cavity multiple times, the optical path of the infrared light is effectively improved, and the photoacoustic effect of the infrared light and the gas to be measured is significantly enhanced, which helps to improve the measurement sensitivity and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The photoacoustic spectroscopy method based on multi-cavity resonance in the present invention measures SF 6 Flow chart of gas decomposition products;

[0027] Figure 2 The photoacoustic spectroscopy method based on multi-cavity resonance in the present invention measures SF 6 Schematic diagram of the structure of the device for gas decomposition products.

[0028] Reference numerals in the figures:

[0029] 1. Signal generator; 2. Laser controller; 3. Continuously tunable laser; 4. Multiple sets of bandpass filters; 5. Photoacoustic spectroscopy resonant cavity; 6. Phase-locked amplifier; 7. Data acquisition device; 8. Computer; 9. Microphone built into the first cavity; 10. First cavity; 11. Air inlet of the buffer cavity; 12. Microphone built into the third cavity; 13. Third cavity; 14. Second cavity; 15. Microphone built into the second cavity; 16. Air outlet of the buffer cavity; 17. Fourth cavity; 18. Microphone built into the fourth cavity; 19. Curved infrared light total reflector; 20. Infrared window; 21. Infrared light collimator; 22. Infrared optical fiber. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of the embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0031] like Figure 1 As shown, embodiment 1 of the present invention provides a photoacoustic spectroscopy method based on multi-cavity resonance to measure SF 6 The device for detecting gas decomposition products comprises: a signal generator 1, a laser controller 2, a continuously tunable laser 3, multiple groups of bandpass filters 4, a photoacoustic spectroscopy resonant cavity 5, a phase-locked amplifier 6, a data acquisition device 7, and a computer 8.

[0032] The signal generator 1, the laser controller 2, the continuously tunable laser 3 and the multiple groups of bandpass filters 4 are connected in sequence. Through the cooperation of the signal generator 1 and the laser controller 2, the period of the infrared light emitted by the continuously tunable laser 3 can be modulated, so as to obtain the infrared light satisfying the SF 6 Infrared light emission period for measurement of gas decomposition products.

[0033] The multiple sets of bandpass filters 4 are used as processing units to modulate the laser emitted by the continuously tunable laser 3 to obtain infrared light of a set wavelength. Since different components have different absorption intensities in infrared light of different wavelengths, the SF 6 The need to measure the concentration of different components in the decomposition products.

[0034] In a preferred but non-limiting embodiment of the present invention, the signal generator 1 is also connected to the phase-locked amplifier 6. The signal generator 1 receives the signal from the phase-locked amplifier 6 and then transmits the periodic signal to the laser controller 3, thereby achieving periodic modulation of the wavelength of infrared light emitted by the continuously tunable laser 3.

[0035] After the multiple groups of bandpass filters 4 modulate the infrared light, the modulated infrared light is transmitted to the photoacoustic spectroscopy resonant cavity 5 through the infrared optical fiber 22 .

[0036] Furthermore, an infrared light collimator 21 is provided on a side of the infrared optical fiber 22 away from the multiple groups of bandpass filters 4 , and the infrared light collimator 21 is used to vertically inject the infrared light into the photoacoustic spectroscopy resonant cavity 5 .

[0037] like Figure 2 As shown, the photoacoustic spectroscopy resonant cavity 5 includes a buffer cavity and a plurality of resonant cavities centrally and symmetrically arranged around the buffer cavity, each resonant cavity is connected to the buffer cavity, forming a plurality of completely identical T-shaped resonant cavities.

[0038] An infrared window 20 is installed on one side of the buffer cavity corresponding to the light transmission side of the infrared light collimator 21. The infrared window 20 is sealed and connected to the buffer cavity, and allows the infrared optical fiber 22 to pass through. The infrared light emitted from the infrared light collimator 21 passes through the infrared window 20 and enters the buffer cavity.

[0039] The buffer cavity has a buffer cavity air inlet 11 and a buffer cavity air outlet 16 respectively at the top and bottom of the buffer cavity. 6 The gas decomposition products enter the buffer cavity from the buffer cavity air inlet 11 .

[0040] In a preferred but non-limiting embodiment of the present invention, the buffer cavity is in a cube shape, each resonance cavity is in a cylindrical shape, there are four resonance cavities, and the four resonance cavities are respectively arranged on the upper, lower, left and right surfaces of the buffer cavity, and the axis of the resonance cavity passes through the center of the buffer cavity.

[0041] The structures and sizes of the four resonant cavities are exactly the same, and are respectively recorded as: the first cavity 10, the second cavity 14, the third cavity 13 and the fourth cavity 17. By setting a common buffer cavity to connect the four resonant cavities, it is possible to avoid the problem that the single T-type resonant cavity is affected by airflow noise, resulting in a larger signal measurement.

[0042] It is worth noting that the cylindrical resonant cavity is only a preferred but non-restrictive embodiment. Those skilled in the art can set the shape of the resonant cavity to other shapes as needed, and the shape of the buffer cavity can also be selected according to the number of resonant cavities, not limited to a cube shape, but it is necessary to satisfy that each resonant cavity and the buffer cavity can cooperate to form a plurality of completely identical T-shaped resonant cavities. Shapes that can meet the above conditions are within the protection scope of the present invention.

[0043] An infrared light reflection unit is arranged inside the buffer cavity; the infrared light reflection unit comprises: a plurality of groups of arc-shaped infrared light total reflection mirrors, each group of arc-shaped infrared light total reflection mirrors 19 comprises arc-shaped infrared light total reflection mirrors 19 arranged on both sides of the buffer cavity, and two adjacent groups of arc-shaped infrared light total reflection mirrors 19 are arranged in parallel. When the infrared light enters the buffer cavity, it is first directed to one arc-shaped infrared light total reflection mirror 19, and is reflected multiple times under the action of the plurality of groups of infrared total reflection mirrors, which effectively enhances the optical path of the infrared light and effectively improves the interaction intensity between the infrared light and the measured gas.

[0044] Each resonance cavity is provided with a built-in microphone, and the four built-in microphones are respectively recorded as: the first cavity built-in microphone 9, the second cavity built-in microphone 15, the third cavity built-in microphone 12 and the fourth cavity built-in microphone 18. The measured gas inside the buffer cavity absorbs the modulated characteristic frequency infrared light, converts the optical information into an acoustic wave signal, and after amplification by the photoacoustic spectroscopy resonance cavity, it is detected by the microphones built in four identical cylindrical resonance cavities, and the acoustic wave signal is converted into an electrical signal. After filtering, it passes through the phase-locked amplifier 6 and the signal collector 7, and finally input into the computer 8. After being divided into four equal parts and taking the average, the computer system completes the operation and concentration calculation of the photoacoustic signal to obtain SF 6 Concentration of gaseous decomposition products.

[0045] Embodiment 2 of the present invention provides a method for measuring SF6 gas decomposition products by photoacoustic spectroscopy based on multi-cavity resonance, using the device for measuring SF6 gas decomposition products by photoacoustic spectroscopy based on multi-cavity resonance in Embodiment 1, the method comprises the following steps:

[0046] Step 1: Place the SF to be tested 6 The gas is introduced into the buffer cavity of the photoacoustic spectroscopy resonant cavity 5;

[0047] Step 2: using the signal generator 1 and the laser controller 2 to modulate the period of the infrared light generated by the continuously tunable laser 3, and inputting the infrared light emitted by the continuously tunable laser 3 into multiple groups of bandpass filters 4 for modulation processing to obtain infrared light with a set period and wavelength;

[0048] Step 3: The modulated infrared light enters the buffer cavity of the photoacoustic spectroscopy resonant cavity 5, and the SF to be measured located inside the buffer cavity 6 When the gas absorbs infrared light, it generates a photoacoustic signal;

[0049] Step 4: Amplify the photoacoustic signal inside the buffer cavity of the gas to be measured using multiple resonance cavities, transmit the photoacoustic signal to a computer, and use the computer to calculate and compute the concentration of the decomposition products of the multi-component gas to be measured.

[0050] Furthermore, obtaining the concentration of the decomposition products of the multi-component gas to be measured by computer operation and calculation includes the following steps:

[0051] Taking the average of the photoacoustic signals from the multiple resonant cavities by computer;

[0052] The mean value is operated and calculated to obtain the concentration of the decomposition products of the multi-component gas to be tested.

[0053] The beneficial effect of the present invention is that compared with the prior art, the photoacoustic spectroscopy resonant cavity provided in the present invention includes a plurality of resonant cavities, and each resonant cavity can be combined with a buffer cavity to form a T-shaped resonant cavity, forming a plurality of completely identical T-shaped resonant cavities. Compared with the single T-shaped photoacoustic structure cavity in the prior art, the present invention can reduce interference factors such as environmental noise and airflow noise by providing a plurality of T-shaped resonant cavities and taking an average value of the measurement results, thereby improving the sensitivity of gas concentration detection. In addition, the infrared light source of the present invention adopts a continuously tunable laser, which can change the period of the output infrared light by electrical modulation, and modulate the infrared light emitted by the continuously tunable laser by a processing unit to obtain infrared light of a specific wavelength, and then input the infrared light modulated by the processing unit into the photoacoustic spectroscopy resonant cavity to analyze the trace gas concentration. By modulating the wavelength and period of the infrared light, the SF 6 The measurement requirements of different component concentrations in decomposition products. Compared with traditional tunable infrared lasers, the price is significantly reduced.

[0054] In order to further enhance the measurement effect, an infrared light reflection unit is also arranged inside the buffer cavity in the present invention. By reflecting the infrared light incident into the buffer cavity multiple times, the optical path of the infrared light is effectively improved, and the photoacoustic effect of the infrared light and the gas to be measured is significantly enhanced, which helps to improve the measurement sensitivity and accuracy.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy, comprising: Infrared light source and photoacoustic spectroscopy resonant cavity (5), characterized in that: The infrared light source is a continuously tunable laser (3), which is connected to a processing unit and is used to emit infrared light according to a set period after being regulated, and transmit the emitted infrared light to the processing unit, and the processing unit modulates the infrared light to obtain infrared light of a set wavelength, and the processing unit then transmits the modulated infrared light to a photoacoustic spectroscopy resonant cavity (5); The photoacoustic spectroscopy resonant cavity (5) comprises: a buffer cavity and a plurality of resonant cavities centrally symmetrically arranged around the buffer cavity; each resonant cavity is connected to the buffer cavity to form a plurality of completely identical T-shaped resonant cavities; The buffer cavity is used to contain the SF6 gas to be tested and receive the infrared light output from the processing unit; the resonant cavity cooperates with the buffer cavity to amplify the photoacoustic signal generated by the SF6 gas to be tested absorbing the infrared light, and the photoacoustic signal is transmitted to the computer (8) after processing to calculate the concentration of the decomposition product of the SF6 gas.

2. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to claim 1, characterized in that: An infrared light reflecting unit is arranged inside the buffer cavity; The infrared light reflecting unit comprises: a plurality of groups of arc-shaped infrared light total reflecting mirrors, which are used to receive the infrared light incident into the buffer cavity and reflect the infrared light multiple times between the plurality of groups of arc-shaped infrared light total reflecting mirrors.

3. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to claim 1, characterized in that: An infrared window (20) is arranged at a position of the buffer cavity for receiving infrared light; An infrared optical fiber (22) for transmitting infrared light to the buffer cavity is disposed at the output end of the infrared light processing unit, an infrared collimator (21) is disposed at one end of the infrared optical fiber (22) away from the infrared light processing unit, and an emission end of the infrared collimator (21) faces the infrared window (20).

4. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to claim 3, characterized in that: The processing units are multiple groups of bandpass filters, one end of each of which is connected to a continuously tunable laser (3), and the other end of each of which is connected to an infrared optical fiber (22).

5. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to claim 1, characterized in that: A microphone is arranged inside each of the resonance cavities. The microphone is used to collect the photoacoustic signal generated by the SF6 gas to be tested absorbing infrared light. The photoacoustic signal is transmitted to a computer (8) after being processed.

6. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to any one of claims 1 to 4, characterized in that: The device also includes: a signal generator (1) and a laser controller (2); The signal generator (1), the laser controller (2) and the continuously tunable laser (3) are connected in sequence and are used to adjust the period of the infrared light emitted by the continuously tunable laser (3).

7. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to claim 4, characterized in that: The device further comprises: a phase-locked amplifier (6) and a data collector (7), wherein the phase-locked amplifier (6) is connected to the signal generator (1), the photoacoustic spectroscopy resonant cavity (5) and the data collector (7); The phase-locked amplifier (6) is used to control the signal generator (1) and amplify the photoacoustic signal output by the photoacoustic spectroscopy resonant cavity (5); the data collector (7) is used to collect and process the photoacoustic signal sent by the phase-locked amplifier (6) and transmit it to the computer (8).

8. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to any one of claims 1 to 4, characterized in that: The buffer cavity is in a cube shape, each resonance cavity is in a cylindrical shape, there are four resonance cavities, and the four resonance cavities are respectively arranged on the upper, lower, left and right surfaces of the buffer cavity, and the axis of the resonance cavity passes through the center of the buffer cavity.

9. The device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to any one of claims 1 to 4, characterized in that: The buffer cavity is also provided with a buffer cavity air inlet (11) for introducing the SF6 gas to be tested and a buffer cavity air outlet (16) for collecting tail gas.

10. A method for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy, using the device for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1, passing the SF6 gas to be measured into the buffer cavity of the photoacoustic spectroscopy resonant cavity (5); Step 2, modulating the period of the infrared light generated by the continuously tunable laser (3), and inputting the infrared light emitted by the continuously tunable laser (3) into a processing unit for modulation processing to obtain infrared light with a set period and wavelength; Step 3, the modulated infrared light enters the buffer cavity in the photoacoustic spectroscopy resonant cavity (5), and the SF6 gas to be measured located inside the buffer cavity absorbs the infrared light to generate a photoacoustic signal; Step 4: Amplify the photoacoustic signal inside the buffer cavity using multiple resonant cavities, transmit the photoacoustic signal to a computer, and calculate the concentration of the decomposition product of the SF6 gas to be measured using the computer.

11. The method for measuring SF6 gas decomposition products by multi-cavity resonance photoacoustic spectroscopy according to claim 10, characterized in that: The concentration of the decomposition products of the multi-component gas to be measured is obtained by computer operation and calculation, which includes the following steps: Taking the average of the photoacoustic signals from the multiple resonant cavities by computer; The mean value is operated and calculated to obtain the concentration of the decomposition products of the multi-component gas to be tested.

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