Photoacoustic spectrometry gas monitoring device for decomposing acetylene from transformer oil
By designing a photoacoustic spectral gas monitoring device for transformer oil decomposition acetylene, using vacuum dynamic degassing and laser photoacoustic spectroscopy technology, the problem of difficulty in detecting acetylene in the transformer in the prior art is solved, and the accurate prediction of early discharge failure of the transformer is achieved.
Patent Information
- Application Number
- CN202421434225.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-21
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-06-21
AI Technical Summary
The prior art is difficult to detect fault characteristic gases dissolved in insulating oil in a timely and accurate manner, especially acetylene, which makes it difficult to predict early discharge failure of the transformer.
A photoacoustic spectral gas monitoring device for transformer oil decomposition acetylene is designed, including a transformer body, a vacuum dynamic headspace degassing device and a laser photoacoustic spectral detection device. The insulating oil is separated by a vacuum dynamic degassing device, and the separated gas enters the laser photoacoustic spectroscopy detection device, and laser photoacoustic spectroscopy technology is used to detect whether there are faulty characteristic gases in the gas.
It realizes rapid and accurate detection of dissolved gases in the transformer, can predict early discharge failures of the transformer, and improves the fault diagnosis and prediction capabilities of electrical equipment.
Smart Images
Figure CN222994313U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of transformer fault detection, and particularly relates to a photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil. Background Art
[0002] A transformer is a core device of the power grid, and its operating state is a key indication of the power supply reliability of the power grid. At present, oil-immersed transformers are widely used. When internal faults, discharge-type faults, or oil and paper aging occur during operation, hydrogen, hydrocarbon gases (such as methane, ethane, ethylene, acetylene, propane, and propylene, etc.), carbon monoxide, carbon dioxide, etc. are usually accompanied. As the faults of the transformer continue to worsen, the gas bubbles formed by the decomposed gas of the transformer dissolve in the oil after convection and diffusion in the oil. Using the method of analyzing dissolved gases in transformer oil to diagnose and predict the faults of the transformer is the main technical means to realize the condition-based maintenance of the transformer at present. The composition and content of the gas generated by the transformer fault are one of the main bases for judging its fault type. Hydrogen and acetylene in the oil are important characteristic gases, which can reflect the early discharge faults of the transformer. Timely and accurately detecting hydrogen and acetylene dissolved in the insulating oil is an effective method for predicting potential internal faults and early diagnosing the development of electrical equipment. Content of the Utility Model
[0003] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide a photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil, which can timely and accurately detect the fault characteristic gases dissolved in the insulating oil to predict the early discharge fault conditions of the transformer.
[0004] The purpose of the utility model is realized by the following technical solutions:
[0005] A photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil includes a transformer body, a vacuum dynamic headspace degassing device, and a laser photoacoustic spectroscopy detection device. The transformer body is connected to the vacuum dynamic headspace degassing device through a pipeline, the vacuum dynamic headspace degassing device is connected to the transformer body through a pipeline, the laser photoacoustic spectroscopy detection device is connected to the vacuum dynamic headspace degassing device, and the laser photoacoustic spectroscopy detection device detects the gas separated by the vacuum dynamic headspace degassing device.
[0006] Further, the laser photoacoustic spectroscopy detection device includes: a laser, a laser controller, a computer, a chopper, a photoacoustic cell, a lock-in amplifier, and a driving unit; the laser is electrically connected to the computer through the laser controller, the chopper is electrically connected to the computer through the driving unit, both the computer and the driving unit are electrically connected to the lock-in amplifier, the driving unit is used to transmit a reference signal of the chopper to the lock-in amplifier, the gas outlet end of the vacuum dynamic headspace degassing device is connected to the photoacoustic cell, the photoacoustic cell is electrically connected to the lock-in amplifier, the photoacoustic cell transmits a photoacoustic signal to the lock-in amplifier, and the lock-in amplifier obtains an intensity detection value of the photoacoustic signal by detecting the acquired reference signal and photoacoustic signal, and transmits it to the computer for subsequent processing.
[0007] Further, the photoacoustic cell includes a cylindrical shell, a channel is arranged axially in the cylindrical shell, a resonance cavity and a buffer chamber are respectively arranged on both axial sides of the cylindrical shell, both the resonance cavity and the buffer chamber are communicated with the channel, windows communicated with the resonance cavity and / or the buffer chamber are arranged at both axial ends of the cylindrical shell, the resonance cavity is used for the gas to generate a photoacoustic effect, the buffer chamber is used to isolate the noise generated by light absorption of the window, an air inlet and an air outlet are arranged on the side wall of the cylindrical shell, the air inlet is communicated with the resonance cavity, and the air outlet is communicated with the buffer chamber.
[0008] Further, the photoacoustic cell further includes a microphone, the microphone is embedded in the cylindrical shell, the sensing end of the microphone is placed in the channel, and the microphone is electrically connected to the lock-in amplifier.
[0009] Further, the axial length of the buffer chamber is 1 / 2 of the axial length of the resonance cavity, and the inner diameter of the buffer chamber is more than three times the inner diameter of the resonance cavity.
[0010] Further, the vacuum dynamic headspace degassing device includes an oil tank and an oil-gas separation device, the transformer body is connected to the oil tank through a pipeline, the oil tank is connected to the oil-gas separation device through a pipeline, the oil-gas separation device is connected to the transformer body through a pipeline, and the oil-gas separation device is used to perform vacuum dynamic headspace degassing on the oil discharged from the transformer body in the oil tank to achieve oil-gas separation.
[0011] Further, there are two oil tanks, and the operations of the two oil tanks are independent of each other. The oil tanks have operations regarding oil inlet, headspace, measurement, and oil discharge, and the operations of the two oil tanks are carried out alternately.
[0012] Further, the model of the chopper is SR540, the model of the microphone is EK3024, the model of the lock-in amplifier is SR830, and the laser is a distributed feedback semiconductor laser from NEL Corporation.
[0013] The utility model has the following beneficial effects:
[0014] 1. By setting the transformer body, the vacuum dynamic headspace degassing device, and the laser photoacoustic spectroscopy detection device, the utility model uses the vacuum dynamic degassing device to separate the oil and gas from the insulating oil discharged from the transformer body. The separated oil liquid flows back to the transformer body, and the separated gas is discharged into the laser photoacoustic spectroscopy detection device. The laser photoacoustic spectroscopy detection device causes the discharged gas to generate a photoacoustic effect and emit a photoacoustic signal. The obtained photoacoustic signal is processed and compared with the reference signal set in the laser photoacoustic spectroscopy detection device (the standard photoacoustic signal emitted when generating a photoacoustic effect in the presence of fault characteristic gases such as acetylene or ethylene), so as to judge whether the photoacoustic signal generated by the gas separated from the transformer belongs to the reference signal. If so, the gas contains fault characteristic gases (such as ethylene or acetylene), which is convenient for predicting the early discharge fault of the transformer and early diagnosing the electrical equipment situation.
[0015] 2. The utility model adopts a finely designed double-chamber differential photoacoustic cell, which reduces the interference of environmental noise, reduces the volume of the gas path, solves the contradictory relationship between environmental noise suppression, acoustic signal enhancement, and gas path volume, and significantly improves the signal-to-noise ratio of acetylene detection.
[0016] 3. Aiming at the problem that the resonance frequency drift affects the measurement result, the utility model adopts the chirp-wavelength combined modulation method, which effectively reduces the temperature sensitivity of the photoacoustic spectroscopy gas monitoring device. The chirp modulation technology realizes the real-time tracking of the resonance frequency of the resonant cavity, greatly reduces the influence of temperature and background gas composition changes on the measurement result, enhances the robustness of the device, and can adapt to high-stability measurement in complex environments.
[0017] 4. The utility model adopts the dynamic headspace degassing technology with high-precision oil temperature control to realize the rapid separation of oil-dissolved acetylene with vibration-convection coordination, and can realize the removal of 50% of the oil-dissolved acetylene with a stable ratio within 1 minute. Description of the Drawings
[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model.
[0019] Figure 2 It is a schematic diagram of the alternate operation process of another tank body of the utility model.
[0020] Figure 3 It is a schematic diagram of the structure of the laser photoacoustic spectroscopy detection device of the utility model.
[0021] Figure 4 This is a schematic structural diagram of the photoacoustic cell of the present utility model.
[0022] In the figure: 1. Transformer body; 2. Vacuum dynamic headspace degassing device; 21. Oil tank; 22. Oil-gas separation device; 3. Laser photoacoustic spectroscopy detection device; 31. Laser; 32. Laser controller; 33. Computer; 34. Chopper; 35. Lock-in amplifier; 36. Driving unit; 4. Photoacoustic cell; 41. Cylindrical shell; 42. Channel; 43. Resonant cavity; 44. Buffer chamber; 45. Window; 46. Inlet; 47. Outlet; 48. Microphone. Specific embodiments
[0023] The present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. Terms such as "upper", "inner", "middle", "left", "right", and "one" cited in this specification are only for the convenience of narration and are not used to limit the scope in which the present utility model can be implemented. Changes or adjustments to their relative relationships shall also be regarded as the scope in which the present utility model can be implemented without substantial changes in technical content.
[0024] A photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil is used to detect gases (especially acetylene or hydrogen) dissolved in the insulating oil in the transformer to predict the early discharge fault conditions of the transformer; as Figures 1 to 4 shown, the laser detection device of the present utility model includes a transformer body 1, a vacuum dynamic headspace degassing device 2, and a laser photoacoustic spectroscopy detection device 3. The transformer body 1 is connected to the vacuum dynamic headspace degassing device 2 through a pipeline, the vacuum dynamic headspace degassing device 2 is connected to the transformer body 1 through a pipeline, the laser photoacoustic spectroscopy detection device 3 is connected to the vacuum dynamic headspace degassing device 2, and the laser photoacoustic spectroscopy detection device 3 detects the gas separated by the vacuum dynamic headspace degassing device 2.
[0025] Thus, the insulating oil in the transformer body 1 is discharged to the vacuum dynamic headspace degassing device 2, and the vacuum dynamic headspace degassing device 2 is used to perform oil-gas separation treatment on the discharged insulating oil. The separated oil flows back to the transformer body 1 through a pipeline, while the separated gas is discharged into the laser photoacoustic spectroscopy detection device 3. The laser photoacoustic spectroscopy detection device 3 is used to detect whether there are fault characteristic gases (such as ethylene or acetylene) in the gas, so as to predict the early discharge fault of the transformer and early diagnose the electrical equipment conditions.
[0026] In this embodiment, in order to separate oil and gas from the insulating oil in the transformer body 1 by using the vacuum dynamic headspace degassing device 2; the vacuum dynamic headspace degassing device 2 includes an oil tank 21 and an oil-gas separation device 22. The transformer body 1 is connected to the oil tank 21 through a pipeline (the inlet oil pipe corresponding to the attached drawing), and the oil tank 21 is connected to the liquid inlet of the oil-gas separator device through a pipeline (the return oil pipe in the enemy camp attached drawing). The liquid outlet of the oil-gas separation device 22 is connected to the transformer body 1 through a pipeline. Among them, the oil-gas separation device 22 is a conventional device in the prior art, and the oil-gas separation device 22 is used to perform vacuum dynamic headspace degassing on the oil liquid (this oil liquid is also called insulating oil) of the transformer body 1 discharged into the oil tank 21 to achieve oil-gas separation. The liquid outlet of the oil-gas separation device 22 returns the separated oil liquid to the transformer body 1 through a pipeline, and its gas outlet 47 is discharged to the laser photoacoustic spectroscopy detection device 3 through a pipeline to detect whether the insulating oil contains fault characteristic gases by using relevant devices.
[0027] The vacuum dynamic headspace degassing device 2 of the present utility model adopts a dynamic headspace degassing technology with high-precision oil temperature control to achieve rapid separation of oil-soluble acetylene with vibration-convection coordination, and can achieve 50% stable proportion of oil-soluble acetylene removal within 1 minute.
[0028] Among them, in order to improve the efficiency of continuously decomposing gas and liquid by the oil-gas separation device 22 and reduce the pause of the oil tank 21 during the laser photoacoustic spectroscopy detection process; therefore, in this embodiment, the number of oil tanks 21 is two, and the operations of the two oil tanks 21 are independent of each other. The operations of the oil tank 21 during actual use are oil inlet (discharging the insulating oil of the transformer body 1), headspace (also called headspace gas chromatography, which is a combined operation technique), measurement, and oil discharge operations. The operations of the two oil tanks 21 in this embodiment are carried out alternately (specifically as Figure 2 shown), so the specific operations of the other two oil tanks 21 are different at the same time to stagger different operations at different time points; it can be seen from this that by setting two oil tanks 21, the interval or waiting time of the oil-gas separation device 22 when receiving oil liquid can be reduced, thereby improving work efficiency.
[0029] In this embodiment, as Figure 3 and Figure 4As shown, the laser photoacoustic spectroscopy detection device 3 mainly uses photoacoustic spectroscopy technology, which is a spectroscopic calorimetry technology based on the photoacoustic effect and directly measures the heat generated by substances due to the absorption of light energy. In the photoacoustic effect of gases, gas molecules absorb modulated infrared radiation of a specific wavelength and are excited to a high-energy state. Since the high-energy state is extremely unstable, the molecules immediately return to the ground state by converting the absorbed light energy into heat in the form of non-radiative transitions. Since the light energy is periodically modulated, the thermal energy of the enclosed gas molecules also changes periodically, which macroscopically manifests as a change in pressure, that is, the generation of sound waves. Since the frequency of the sound wave is the same as the modulation frequency of the light source, and its intensity is related to the volume fraction of the absorbing gas, by establishing a quantitative relationship between the gas volume fraction and the sound wave intensity, the volume fraction of each gas can be accurately monitored. Since fault characteristic gases (such as acetylene or hydrogen) are usually dissolved in insulating oil, after detection by the laser photoacoustic spectroscopy detection device 3, the percentage of the corresponding value is displayed.
[0030] Based on the above description of photoacoustic spectroscopy technology, the structure of the laser photoacoustic spectroscopy detection device 3 will be further introduced below. The laser photoacoustic spectroscopy detection device 3 includes: a laser 31, a laser controller 32, a computer 33, a chopper 34 (the model of the chopper 34 is SR540), a photoacoustic cell 4, a lock-in amplifier 35 (the model of the lock-in amplifier 35 is SR830), and a drive unit 36. The laser 31 is electrically connected to the computer 33 through the laser controller 32, the chopper 34 is electrically connected to the computer 33 through the drive unit 36, both the computer 33 and the drive unit 36 are electrically connected to the lock-in amplifier 35, and the drive unit 36 is used to transmit a reference signal of the chopper 34 to the lock-in amplifier 35. This reference signal is based on the laser 31 simulating the emission of a certain fault characteristic gas (such as ethylene or acetylene), and is a standard photoacoustic signal generated by the chopper 34 through the photoacoustic effect. The gas outlet end of the vacuum dynamic headspace degassing device 2 is connected to the photoacoustic cell 4, the photoacoustic cell 4 is electrically connected to the lock-in amplifier 35, and the photoacoustic cell 4 transmits a photoacoustic signal to the lock-in amplifier 35. The lock-in amplifier 35 processes and compares the obtained photoacoustic signal with the reference signal, and then judges whether the photoacoustic signal generated by the gas separated from the transformer belongs to the reference signal. If so, there is a fault characteristic gas (such as ethylene or acetylene) in the gas, which is convenient for predicting the early discharge fault of the transformer and the early diagnosis of the electrical equipment situation.
[0031] Among them, the laser 31 in this embodiment uses a distributed feedback semiconductor laser 31 from NEL Corporation and serves as the light source of the laser optoacoustic spectroscopy detection device 3. At the same time, regarding the optoacoustic effect of the gas excited by the laser 31, a necessary condition is that the operating wavelength of the laser 31 is consistent with the characteristic absorption spectral line of the gas. In order to make the absorption of acetylene in the infrared radiation stronger, an absorption spectrum with strong absorption at a high intensity in this band is selected for acetylene. The wavelength corresponding to the absorption spectral line of this high-intensity absorption is 1520 nm and is used as the operating wavelength of the laser 31. Therefore, in addition to acetylene, fault characteristic gases such as ethane and ethylene do not absorb infrared radiation with a wavelength of 1520 nm. Therefore, the laser 31 selected in this embodiment is mainly for detecting acetylene gas.
[0032] Based on this, the laser 31 in this embodiment emits infrared radiation with a specific wavelength that can be absorbed by acetylene molecules. After being modulated into an intermittent light beam with a certain frequency by the chopper 34, it is incident along the longitudinal axis of the photoacoustic cell 4. At this time, the gas is excited by the periodic light beam to produce an optoacoustic effect; the sine wave signal detected by the photoacoustic cell 4 and the square wave signal output by the chopper 34 are respectively sent into the lock-in amplifier 35 as the photoacoustic signal (signal to be detected) and the reference signal. After cross-correlation detection, the intensity value of the photoacoustic signal is extracted and transmitted to the computer 33 for subsequent processing. Among them, the intensity value of the photoacoustic signal can reflect the percentage of the acetylene volume fraction in the gas and can also reflect whether there is acetylene in the insulating oil from the side, thereby facilitating the prediction of early discharge faults of transformers and the early diagnosis of the conditions of electrical equipment.
[0033] In this embodiment, as Figure 4 shown, the photoacoustic cell 4 includes a cylindrical shell 41 and a microphone 48 (the model of the microphone 48 is EK3024). The cylindrical shell 41 is provided with a channel 42 along the axial direction. Resonant cavities 43 and buffer chambers are respectively arranged on both sides of the cylindrical shell 41 along the axial direction. The resonant cavities 43 and the buffer chambers are both communicated with the channel 42. Windows 45 communicated with the resonant cavities 43 and / or the buffer chambers are arranged at both ends of the cylindrical shell 41 along the axial direction. The windows 45 are made of quartz materials. The resonant cavities 43 are used for the gas to produce an optoacoustic effect, and the buffer chamber 44 is used to isolate the noise generated by the light absorption of the windows 45. An air inlet 46 and an air outlet 47 are arranged on the side wall of the cylindrical shell 41. The air inlet 46 is communicated with the resonant cavity 43, and the air outlet 47 is communicated with the buffer chamber. The microphone 48 is embedded in the cylindrical shell 41, the sensing end of the microphone 48 is placed in the channel 42, and the microphone 48 is electrically connected to the lock-in amplifier 35.
[0034] Thus, by providing a communicating resonance cavity 43 and a buffer chamber 44 in the cylinder shell 41, the gas separated by the oil-gas separation device 22 is discharged into the resonance cavity 43 through the air inlet 46, and then discharged out of the cylinder shell 41 through the channel 42, the buffer chamber 44 and the air outlet 47. During this process, photoacoustic effect is generated in the resonance cavity 43, and the corresponding photoacoustic signal is induced by the microphone 48 through the channel 42 and transmitted to the lock-in amplifier 35. During the photoacoustic effect process, the buffer chamber 44 can isolate the noise generated by the window 45 due to light absorption, so as to improve the accuracy of the photoacoustic signal.
[0035] Aiming at the problem that the resonance frequency drift affects the measurement result, the utility model adopts a chirp-wavelength combined modulation method, which effectively reduces the temperature sensitivity of the photoacoustic spectroscopy gas monitoring device. The chirp modulation technology realizes the real-time tracking of the resonance frequency of the resonance cavity 43, greatly reduces the influence of temperature and background gas composition changes on the measurement result, enhances the robustness of the device, and can adapt to high-stability measurement in complex environments.
[0036] Meanwhile, the axial length of the buffer chamber is 1 / 2 of the axial length of the resonance cavity 43, and the inner diameter of the buffer chamber is more than three times the inner diameter of the resonance cavity 43. Such a setting can improve the noise isolation effect of the resonance cavity 43. In this embodiment, the length of the resonance cavity 43 is taken as 10 cm and the diameter is taken as 1 cm; the length of the buffer chamber 44 is taken as 5 cm and the diameter is taken as 4 cm.
[0037] The photoacoustic cell 4 adopts a refined double-chamber differential photoacoustic cell, which reduces the interference of environmental noise, reduces the volume of the gas path, solves the contradictory relationship among environmental noise suppression, acoustic signal enhancement and gas path volume, and significantly improves the signal-to-noise ratio of acetylene detection.
[0038] In summary, the utility model provides a transformer body 1, a vacuum dynamic headspace degassing device 2 and a laser photoacoustic spectroscopy detection device 3. The vacuum dynamic degassing device is used to separate oil and gas from the insulating oil discharged from the transformer body 1. The separated oil liquid flows back to the transformer body 1, and the separated gas is discharged into the laser photoacoustic spectroscopy detection device 3. The laser photoacoustic spectroscopy detection device 3 is used to generate photoacoustic effect on the discharged gas and emit photoacoustic signals. The obtained photoacoustic signals are processed and compared with the reference signals set in the laser photoacoustic spectroscopy detection device 3 (the standard photoacoustic signals emitted when generating photoacoustic effect in the presence of fault characteristic gases such as acetylene or ethylene), and then it is judged whether the photoacoustic signals generated by the gas separated from the transformer belong to the reference signals. If so, there are fault characteristic gases (such as ethylene or acetylene) in the gas, which is convenient for predicting the early discharge faults of the transformer and early diagnosing the conditions of electrical equipment.
[0039] The embodiments of the present utility model are not limited thereto. According to the above content of the present utility model, by using the common general technical knowledge and customary means in the art, without departing from the above basic technical idea of the present utility model, the present utility model can also be modified, replaced or combined in various other forms, all of which fall within the scope of the protection of the rights of the present utility model.
Claims
1. A photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil, characterized in that: It includes a transformer body, a vacuum dynamic headspace degassing device and a laser photoacoustic spectrum detection device. The transformer body is connected to the vacuum dynamic headspace degassing device through a pipeline, the vacuum dynamic headspace degassing device is connected to the transformer body through a pipeline, the laser photoacoustic spectrum detection device is connected to the vacuum dynamic headspace degassing device, and the laser photoacoustic spectrum detection device detects the gas separated by the vacuum dynamic headspace degassing device.
2. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil according to claim 1, characterized in that: The laser photoacoustic spectroscopy detection device includes: a laser, a laser controller, a computer, a chopper, a photoacoustic cell, a phase-locked amplifier and a driving unit; the laser is electrically connected to the computer through the laser controller, the chopper is electrically connected to the computer through the driving unit, the computer and the driving unit are both electrically connected to the phase-locked amplifier, the driving unit is used to transmit a reference signal of the chopper to the phase-locked amplifier, the gas outlet end of the vacuum dynamic headspace degassing device is connected to the photoacoustic cell, the photoacoustic cell is electrically connected to the phase-locked amplifier, the photoacoustic cell transmits a photoacoustic signal to the phase-locked amplifier, the phase-locked amplifier obtains an intensity detection value of the photoacoustic signal by detecting the acquired reference signal and the photoacoustic signal, and transmits the intensity detection value to the computer for subsequent processing.
3. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil according to claim 2, characterized in that: The photoacoustic cell comprises a shell, the shell is provided with a channel in the axial direction, a resonance cavity and a buffer chamber are respectively provided on both sides of the shell in the axial direction, the resonance cavity and the buffer chamber are both communicated with the channel, windows communicated with the resonance cavity and / or the buffer chamber are provided at both ends of the shell in the axial direction, the resonance cavity is used for gas to produce photoacoustic effect, the buffer chamber is used to isolate noise generated by light absorption by the window, and an air inlet and an air outlet are provided on the side wall of the shell, the air inlet is communicated with the resonance cavity, and the air outlet is communicated with the buffer chamber.
4. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil according to claim 3, characterized in that: The photoacoustic cell further comprises a micro-sound device, which is embedded in the cylindrical shell, and the sensing end of the micro-sound device is placed in the channel, and the micro-sound device is electrically connected to the lock-in amplifier.
5. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil according to claim 3, characterized in that: The length of the buffer chamber along the axial direction is 1 / 2 of the length of the resonance cavity along the axial direction, and the inner diameter of the buffer chamber is greater than three times the inner diameter of the resonance cavity.
6. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil according to claim 1, characterized in that: The vacuum dynamic headspace degassing device comprises an oil tank and an oil-gas separation device. The transformer body is connected to the oil tank via a pipeline, the oil tank is connected to the oil-gas separation device via a pipeline, and the oil-gas separation device is connected to the transformer body via a pipeline. The oil-gas separation device is used to perform vacuum dynamic headspace degassing on the oil of the transformer body discharged from the oil tank to achieve oil-gas separation.
7. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene from transformer oil according to claim 6, characterized in that: There are two oil tanks, and the work in the two oil tanks is independent of each other. The oil tanks are related to oil filling, head space, measurement and oil discharge operations, and the operations of the two oil tanks are performed alternately.
8. The photoacoustic spectroscopy gas monitoring device for decomposing acetylene in transformer oil according to claim 4, characterized in that: The model of the chopper is SR540, the model of the micro-acoustic device is EK3024, the model of the phase-locked amplifier is SR830, and the laser is a distributed feedback semiconductor laser from NEL Company.