A device and method for rapid detection of oil-soluble fault characteristic gases

Abstract

The application discloses a kind of oil-dissolved characteristic gas rapid detection device and method, the device includes: photoacoustic cell and the light source component of laser emission to the photoacoustic cell, the light source component is controlled by control component control;The control component acquires the sound signal of current photoacoustic effect in the photoacoustic cell to obtain the concentration of current characteristic gas, according to the concentration of current characteristic gas in the photoacoustic cell adjusts the laser output by the light source component.Accordingly, the present device realizes the dynamic adjustment of the adaptive matching of photoacoustic parameters and gas concentration by feedback adjustment, to ensure the accuracy of light source modulation under different characteristic gas concentrations.This way, during the photoacoustic spectroscopy detection process based on the method, it can quickly respond to the change of characteristic gas concentration, and make the light source match the current characteristic gas concentration, to improve the detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of trace detection technology for power transformers, and in particular to a device and method for rapid detection of characteristic gases in oil-soluble faults. Background Technology

[0002] Power transformers are core equipment in the power grid, and their operational reliability affects the grid's safety and stability. Most transformer faults gradually evolve from minor internal defects. Transformers are complex, fully sealed enclosures, making internal defects difficult to detect through external measurement methods. However, the resulting discharges or overheating can cause a series of chemical reactions in the transformer's insulating oil and insulating paper, generating different types of fault-specific gases that dissolve in the transformer oil. Similar to blood tests used to diagnose human diseases, detecting or monitoring the concentration and proportion of dissolved characteristic gases in the oil can promptly identify most internal hazards and defects in the transformer.

[0003] Currently, photoacoustic spectroscopy, based on the photoacoustic effect, is commonly used to rapidly detect dissolved gases in transformer oil, thereby providing early warning of transformer faults. During detection, different concentrations of characteristic gases require corresponding light source modulation. However, existing photoacoustic spectroscopy-based detection equipment struggles to quickly and accurately modulate the light source to suit the concentration of the characteristic gas, affecting detection efficiency and results. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rapid detection device and method for oil-soluble fault characteristic gases, which can quickly and accurately modulate a light source adapted to the concentration of the characteristic gas, thereby obtaining better detection efficiency and results.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, this application discloses a rapid detection device for oil-soluble fault characteristic gases, comprising a photoacoustic cell and a light source assembly that emits laser light into the photoacoustic cell, the light source assembly being controlled by a control assembly; the photoacoustic cell has a cylindrical body that defines a resonant cavity, and the resonant cavity is connected to an air inlet window for introducing oil-soluble gas containing the characteristic gas; the control assembly acquires the acoustic signal generated by the current photoacoustic effect in the photoacoustic cell to obtain the current concentration of the characteristic gas, and adjusts the laser light output by the light source assembly according to the current concentration of the characteristic gas in the photoacoustic cell.

[0007] Its beneficial effects are as follows: Compared to the traditional static modulation mode of the light source, which suffers from a lag in response to the concentration of the characteristic gas, this device dynamically adjusts the laser output from the light source component by acquiring the characteristic gas concentration in real time and then adjusting the laser parameters to match the characteristic gas concentration. This ensures the accuracy of light source modulation under different characteristic gas concentrations. In this way, while maintaining the stability of the resonant cavity, the response time of light source modulation can be shortened; and a synchronous closed loop of concentration detection and light source modulation can be achieved, overcoming the modulation delay and accuracy degradation problems caused by existing equipment relying on empirical parameter libraries. Therefore, in the photoacoustic spectroscopy detection process based on this method, it can react quickly to changes in characteristic gas concentration to improve detection sensitivity and ensure that the light source matches the current characteristic gas concentration to improve detection accuracy.

[0008] Preferably, the longitudinal section of the cylinder is a hyperbola, and the light source assembly emits laser light along the axial direction of the cylinder.

[0009] Its beneficial effects are: the hyperbolic longitudinal section can realize multi-frequency operation, so the resonant cavity can be used to realize the rapid detection method of oil-soluble fault characteristic gas in the above embodiment, so as to meet the different resonant frequencies required by different characteristic gas concentrations in the resonant cavity based on its ability to operate at multiple frequencies, thereby rapidly responding to changes in characteristic gas concentration in the resonant cavity.

[0010] Specifically, the axial length of the resonant cavity is 100mm, the minor axis of the hyperbola is 2.5mm, and the eccentricity of the generatrix is ​​7.14mm; and the 40mm×50mm size is symmetrically distributed by the waisted resonant cavity.

[0011] Specifically, the control components include: a data acquisition unit, a lock-in amplifier, a computational controller, a function generator, a buffer, and a light source controller; the data acquisition unit is connected to the input terminals of the lock-in amplifier and the function generator, one output terminal of the function generator is connected to the input terminal of the buffer, and the other output terminal is connected to the input terminal of the lock-in amplifier; the computational controller and the lock-in amplifier are bidirectionally connected to send signals to each other; the output terminal of the buffer is connected to one input terminal of the light source controller, and the output terminal of the lock-in amplifier is connected to the other input terminal of the light source controller; the output terminal of the light source controller is connected to the light source assembly.

[0012] Secondly, this application discloses a rapid detection method for oil-soluble fault characteristic gases, implemented based on the aforementioned rapid detection device for oil-soluble fault characteristic gases, wherein the control component performs the following steps:

[0013] S100: The light source assembly emits a laser with set light source parameters into the photoacoustic cell and introduces an oil-soluble gas containing the characteristic gas into the photoacoustic cell; S200: The collector collects the acoustic signal generated by the photoacoustic effect in the photoacoustic cell and transmits it to the lock-in amplifier and the function generator; S300: After demodulating the acoustic signal, the lock-in amplifier calculates the current concentration of the characteristic gas in the oil-soluble gas and inputs it to the calculation controller, which generates a light source modulation signal corresponding to the concentration of the characteristic gas; S400: The light source controller controls the light source assembly according to the light source modulation signal to adjust the laser so that it conforms to the current concentration of the characteristic gas.

[0014] Its beneficial effects are as follows: Through the coordinated operation of the lock-in amplifier and the computational controller, rapid response and detection of characteristic gases are achieved. Furthermore, by accurately controlling the light source controller through the computational controller and the lock-in amplifier, the laser is adjusted to match the current characteristic gas concentration, frequency, and other parameters, effectively improving the reliability of the detection results and reducing the possibility of false alarms and missed alarms. The integration of the light source controller, signal generator, and function generator enables the device to automatically adjust the modulation signal of the light source to adapt to the detection of characteristic gases of different concentrations, improving the ease of operation and the level of automation.

[0015] Specifically, S100 includes: S110, introducing the oil-soluble gas containing the characteristic gas into the resonant cavity; S120, outputting the light source parameter signal corresponding to the characteristic gas preset by the computing controller to the lock-in amplifier, the lock-in amplifier extracting the light source parameters from the light source parameter signal, and then transmitting the light source parameters to the signal generator; S130, the signal generator converting the light source parameters into a first light source drive signal readable by the light source controller, and outputting it to the light source controller; S140, the light source controller adjusting the light source component according to the first light source drive signal.

[0016] In some embodiments, S300 specifically includes: S310, the function generator acquires the acoustic signal collected by the collector to obtain the current resonant frequency of the photoacoustic cell, outputs the resonant frequency as a reference frequency, so that the lock-in amplifier demodulates the acoustic signal output by the collector according to the reference frequency, and extracts first information related to the concentration of the characteristic gas after demodulation; S320, the first information is transmitted to the computing controller, and the computing controller calculates the concentration of the characteristic gas according to the first information; S330, a light source modulation signal is generated according to the calculated concentration of the characteristic gas, wherein the computing controller generates the light source modulation signal according to the calculated concentration of the characteristic gas, and wherein the computing controller is configured with a preset relationship between the concentration of the characteristic gas and the light source parameters.

[0017] Specifically, S400 includes: S410, the computing controller transmits the light source modulation signal to the lock-in amplifier, the lock-in amplifier extracts the modulation parameters in the light source modulation signal, and then transmits them to the signal generator; S420, the signal generator converts the modulation parameters into a second light source driving signal readable by the light source controller, so as to adjust the light source component according to the second light source driving signal. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a rapid detection device for oil-soluble fault characteristic gases according to an embodiment of this application;

[0019] Figure 2 This is a flowchart of a rapid detection method for oil-soluble fault characteristic gases according to an embodiment of this application;

[0020] Figure 3 This is a flowchart of a rapid detection method for oil-soluble fault characteristic gases according to an embodiment of this application;

[0021] In the picture:

[0022] 1-Light source, 2-Modulator, 3-Collimator;

[0023] 4-Photoacoustic cell, 12-Left air chamber, 13-Right air chamber, 14-Resonant cavity, 15-Inlet window, 16-Exhaust window, 17-Reflector, 18-Microphone;

[0024] 5-Acquisition unit, 6-Lock-in amplifier, 7-Computational controller, 8-Signal generator, 9-Function generator, 10-Buffer, 11-Light source controller. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In existing technologies, the commonly used characteristic gases dissolved in transformer oil for determining whether a transformer is faulty mainly include seven: hydrogen (H2), methane (CH4), ethane (C2H6), ethylene (C2H4), acetylene (C2H2), carbon monoxide (CO), and carbon dioxide (CO2). Among these, the detection of acetylene plays a crucial role in detecting characteristic gases dissolved in transformer oil, and is of significant practical importance for transformer fault diagnosis, condition monitoring, and maintenance. The detection of acetylene dissolved in oil will be used as an example in the following explanation.

[0027] See Figure 1 This invention provides a technical solution: a rapid detection device for oil-soluble fault characteristic gases, comprising: a photoacoustic cell 4 and a light source assembly that emits laser light into the photoacoustic cell 4, the light source assembly being controlled by a control assembly; the photoacoustic cell 4 has a cylindrical body defining a resonant cavity 14, and the resonant cavity 14 is connected to an air inlet window 15 for introducing oil-soluble gas containing characteristic gases. The oil-soluble gas can be a mixed gas extracted from transformer oil (containing various characteristic gases), or it can be oil containing various characteristic gases. The control assembly collects the acoustic signal generated by the current photoacoustic effect within the photoacoustic cell 4 to obtain the current concentration of the characteristic gas. Here, the characteristic gas is acetylene; however, in different detection situations, other gases may also be used, which will not be elaborated here. The laser light output from the light source assembly is adjusted according to the current concentration of the characteristic gas within the photoacoustic cell 4.

[0028] Specifically, when the characteristic gas enters the resonant cavity 14 of the photoacoustic cell 4, its molecules absorb the specific wavelength laser energy emitted by the laser, generating a thermal relaxation effect. The intensity of the excited acoustic signal is positively correlated with the gas concentration, i.e., a photoacoustic effect is generated. Then, the control component can calculate the current gas concentration based on the specific relationship of the photoacoustic effect, and generate a modulation signal adapted to the current characteristic gas in real time according to the obtained characteristic gas concentration, so that the laser emitted by the current light source 1 can be adapted to the specific concentration. This allows the light source to respond quickly to the concentration of the characteristic gas.

[0029] Therefore, compared to the traditional static modulation mode of the light source, which suffers from lag in response to the concentration of the characteristic gas, this device achieves dynamic adjustment of the laser parameters to match the characteristic gas concentration by acquiring the characteristic gas concentration in real time and then adjusting the laser output from the light source component based on the gas concentration. This ensures the accuracy of modulating the light source 1 under different characteristic gas concentrations. In this way, while maintaining the stability of the resonant cavity 14, the response time of the light source 1 modulation can be shortened; and a synchronous closed loop of concentration detection and modulation of the light source 1 can be achieved, overcoming the modulation delay and accuracy attenuation problems caused by existing equipment relying on empirical parameter libraries.

[0030] Therefore, in the photoacoustic spectroscopy detection process based on this method, it can respond quickly to changes in the concentration of characteristic gas to improve detection sensitivity, and make light source 1 match the current concentration of characteristic gas to improve detection accuracy.

[0031] Continue to refer to Figure 1 As shown, in some embodiments, the longitudinal section of the cylindrical body within the photoacoustic cell 4 that defines the resonant cavity 14 is hyperbolic, thereby constructing the resonant cavity 14 as a waisted structure, and the light source assembly emits laser light along the axial direction of the cylindrical body.

[0032] It is worth noting that conventional cylindrical resonant cavities have a limited frequency range that they can cover during photoacoustic responses due to their own structure. Furthermore, the natural frequency of the characteristic gas changes with the concentration of the characteristic gas. Therefore, conventional cylindrical resonant cavities cannot operate at multiple frequencies, making them unsuitable for the above-mentioned methods and lacking good detection sensitivity and stability.

[0033] Compared to conventional resonant cavities, the resonant cavity 14 in this application, which is constructed with a hyperbola in the longitudinal section of a cylindrical body and forms a waisted structure, can cover a wider frequency range. In other words, the resonant cavity 14 in the device of this application embodiment can achieve multi-frequency operation.

[0034] Based on this, the resonant cavity 14, which can realize multiple frequency points, can be used to realize the rapid detection method of oil-soluble fault characteristic gas in the above embodiment. Based on its ability to operate at multiple frequency points, it can meet the resonant frequency inside the resonant cavity 14 required according to different characteristic gas concentrations, thereby rapidly responding to changes in characteristic gas concentration inside the resonant cavity 14.

[0035] Furthermore, compared to conventional cylindrical resonant cavities, the waisted resonant cavity 14 also has better sensitivity and anti-interference capabilities.

[0036] In a preferred example, the resonant cavity 14 has an axial length of 100 mm, a hyperbola in its longitudinal section with a minor axis of 2.5 mm, and a generatrix with an eccentricity of 7.14 mm. By defining the resonant cavity 14 as described above, better test results can be obtained.

[0037] In some specific embodiments, the light source assembly includes: a light source 1, a modulator 2, and a collimator 3. The control assembly includes: a collector 5, a lock-in amplifier 6, a computational controller 7, a function generator 9, a buffer 10, and a light source controller 11.

[0038] Light source 1 is connected to modulator 2, modulator 2 is connected to collimator 3, and collimator 3 is installed at one end of photoacoustic cell 4; collector 5 is connected to the input of lock-in amplifier 6 and the input of function generator 9, one output of function generator 9 is connected to the input of buffer 10, and the other output is connected to the input of lock-in amplifier 6; calculation controller 7 is bidirectionally connected to lock-in amplifier 6 to send signals to each other; the output of buffer 10 is connected to one input of light source controller 11, and the output of lock-in amplifier 6 is connected to the other input of light source controller 11; the output of light source controller 11 is connected to light source assembly.

[0039] Light source 1 provides optical signals. For example, light source 1 is a laser. The coherence of the laser makes the photoacoustic signal easier to detect and demodulate by lock-in amplifier 6. The emitted optical signal can be precisely controlled by electronic control equipment. Combined with light source controller 11, precise modulation of laser output can be achieved.

[0040] Modulator 2 converts the control signal output by light source controller 11 into an optical signal and modulates the optical signal emitted by light source 1 into the optimal signal for acetylene gas absorption. For example, modulator 2 is a mechanical chopper. Using a mechanical chopper in photoacoustic cell 4 can reduce background noise because the chopper can only allow light of a specific modulation frequency to pass through, thereby reducing interference from other frequency light.

[0041] Collimator 3 collimates the divergent light into an approximately parallel beam with a very small divergence angle, thereby improving the coupling efficiency of the optical signal emitted from light source 1. For example, the collimator is a fiber optic collimator. In high-requirement scenarios, fiber optic collimators have anti-backlight capability and can withstand high output power, which is particularly important for high-power beams that may be encountered in photoacoustic spectroscopy detection.

[0042] The photoacoustic cell 4 includes a left gas chamber 12, a right gas chamber 13, a resonant cavity 14, an air inlet window 15, an exhaust window 16, a reflector 17, and a microphone 18. The left gas chamber 12 has an air inlet window 15, through which dissolved gases in the transformer oil are buffered before entering the resonant cavity 14 of the photoacoustic cell 4. The right gas chamber 13 has an exhaust window 16, through which dissolved acetylene gas in the transformer oil is buffered before being discharged from the photoacoustic cell 4. In this example, the air inlet window 15 allows dissolved acetylene gas from the transformer oil to enter the left gas chamber 12 from the transformer oil; the exhaust window 16 allows acetylene gas to be discharged to the air or a specific unit. Preferably, the left gas chamber 12 and the right gas chamber 13 are 40mm × 40mm × 50mm in size and are symmetrically distributed and connected by the waisted resonant cavity 14 to reduce interference with the detection results and improve the stability of the detection.

[0043] Microphone 18 converts the acoustic signal generated by the photoacoustic effect into an electrical signal that can be acquired by the acquisition device 5. For example, microphone 18 is a piezoelectric microphone, which has the advantages of high sensitivity, fast response and wide bandwidth response.

[0044] Next, this application discloses a rapid detection method for oil-soluble fault characteristic gases. For better illustration, the process of implementing this method using the aforementioned rapid detection device for oil-soluble fault characteristic gases will be used as an example, referring to... Figures 1-3 To understand this, the rapid detection method for characteristic gases of oil-soluble faults includes the following steps performed by the control component:

[0045] S100: The light source assembly emits a laser with set light source parameters into the photoacoustic cell 4, and introduces an oil-soluble gas containing acetylene gas into the photoacoustic cell 4.

[0046] Specifically, it includes:

[0047] S110. The gas dissolved in the transformer oil is introduced into the resonant cavity 14. The gas contains acetylene gas. The gas enters the left gas chamber 12 of the photoacoustic cell 4 through the air inlet window 15 and then enters the resonant cavity 14 of the photoacoustic cell 4. As the gas diffuses, it fills the right gas chamber 13 of the photoacoustic cell 4.

[0048] S120. The light source parameter signal corresponding to acetylene gas preset by the calculation controller 7 is output to the lock-in amplifier 6. The lock-in amplifier 6 extracts the light source parameter from the light source parameter signal and then transmits the light source parameter to the signal generator 8.

[0049] S130, the signal generator 8 converts the light source parameters into a light source drive signal that can be read by the light source controller 11. Here, to distinguish it from the following text, the light source drive signal is defined as the first light source drive signal and output to the light source controller 11.

[0050] S140, the light source controller 11 adjusts the laser according to the first light source driving signal. Specifically, the light source controller 11 controls the modulator 2 according to the light source driving signal. The modulator 2 modulates the laser signal emitted from the light source 1 into an optimal laser signal absorbed by acetylene gas. Here, the modulation process can be any modulation method such as wavelength modulation. Specifically, the modulator 2 modulates the divergent laser signal, and then after being collimated by the collimator 3, it becomes an approximately parallel beam with a very small divergence angle, which is then injected into the photoacoustic cell 4.

[0051] It is understandable that the laser signal output in the above manner is intended to generate a repetitive photoacoustic effect in the photoacoustic cell 4. That is, when acetylene gas is present in the dissolved gas of the transformer, part of the laser signal injected into the photoacoustic cell 4 is absorbed by the acetylene gas to generate a photoacoustic effect, and part of it is reflected by the reflector 17 and re-enters the resonant cavity 14 to generate a photoacoustic effect.

[0052] S200, the acquisition unit 5 acquires the acoustic signal generated by the photoacoustic effect in the photoacoustic cell 4; specifically, the acquisition unit 5 is a microphone 18. After the acoustic signal of the photoacoustic effect is detected by the microphone 18, it is converted into an electrical signal for transmission. The acquisition unit 5 acquires the electrical signal converted and transmitted by the microphone 18 and sends it to the lock-in amplifier 6 and the function generator 9.

[0053] After demodulating the acoustic signal, S300 and lock-in amplifier 6 calculate the current acetylene gas concentration and input it to the calculation controller 7. The calculation controller 7 generates a modulation signal for the light source 1 corresponding to the characteristic gas concentration. Specifically, this includes:

[0054] S310, the function generator 9 acquires the acoustic signal collected by the acquisition unit 5 to obtain the resonant frequency of the photoacoustic cell 4, and outputs the resonant frequency as the reference frequency, that is, the reference frequency is the same as the resonant frequency of the photoacoustic cell 4, so that the lock-in amplifier 6 demodulates the acoustic signal output by the acquisition unit 5. After demodulating the photoacoustic spectrum of the acoustic signal, the lock-in amplifier 6 extracts information related to the acetylene gas concentration, such as the Fourier transform of sound pressure and sound velocity. Here, for better distinction, the information related to the acetylene gas concentration is defined as the first information.

[0055] S320. The first information is transmitted to the computing controller 7. The computing controller 7 calculates the concentration of acetylene gas. Specifically, the sound pressure change in the photoacoustic cell 4 can preferably be calculated using the active Helmholtz equation, expressed by the following formula:

[0056]

[0057] In the formula:

[0058] Fourier transform representing sound pressure;

[0059] k represents the coefficient, expressed by the following formula.

[0060]

[0061] In the formula:

[0062] v represents the speed of sound;

[0063] Indicates specific heat capacity at constant pressure Heat capacity at constant volume The ratio.

[0064] Because the absorption transitions of gas molecules within the cavity are unsaturated, and the modulation frequency of the laser heat source is much smaller than the relaxation rate of the gas molecule transitions, the heat source... From the following formula:

[0065]

[0066] In the formula:

[0067] This indicates the intensity of the laser light incident on the photoacoustic cell;

[0068] α represents the absorption coefficient of the gas in the pool;

[0069] This represents the total number density of gas molecules in the pool;

[0070] This represents the absorption cross section of the gas molecules within the cell;

[0071] This indicates the volume concentration of acetylene gas.

[0072] Laser output power;

[0073] The normalization function represents the distribution of light energy.

[0074] Understandably, after the device performs the above steps, it achieves rapid response and detection of acetylene gas through the coordinated operation of the lock-in amplifier 6 and the computing controller 7, thereby improving detection efficiency.

[0075] S330, the calculation controller 7 generates a modulation signal for the light source 1 based on the calculated acetylene concentration. Specifically, the calculation controller 7 has a preset relationship between the acetylene concentration and the parameters of the light source 1. Based on the input acetylene concentration and other relevant parameters, the corresponding modulation parameters can be obtained. In order to send the modulation parameters, they are converted into a modulation signal for the light source 1. For example, the modulation parameters of the light source 1 are encoded to convert them into a modulation signal for the light source 1, or after encoding, digital-to-analog conversion is performed to convert them into an analog signal, etc.

[0076] S400, the light source controller 11 controls the light source assembly according to the light source modulation signal to adjust the parameters of the light source 1 so that it conforms to the current concentration of the characteristic gas.

[0077] Specifically, it includes:

[0078] S410, the computing controller 7 transmits the modulation signal of the light source 1 to the lock-in amplifier 6. The lock-in amplifier 6 extracts the modulation parameters in the light source modulation signal and then transmits them to the signal generator 8. Here, the modulation parameters and the light source parameters mentioned above can both include the wavelength, amplitude, etc. of the light source.

[0079] S420, the signal generator 8 converts the modulation parameters into a light source drive signal that can be read by the light source controller 11. To distinguish it from the above, this light source drive signal is defined here as the second light source drive signal. The light source controller 11 controls the light source assembly to adjust the laser according to the second light source drive signal so that the laser is more consistent with the concentration of the current characteristic gas.

[0080] Understandably, the integration of the light source controller 11, signal generator 8, and function generator 9 enables the device to automatically adjust the modulation signal of the light source to adapt to the detection of different concentrations of acetylene, thereby improving the convenience and automation of operation. Furthermore, since the light source is compatible with the current acetylene concentration, the reliability of the detection results is also improved, reducing the possibility of false alarms and missed alarms.

[0081] To ensure that the frequency of the light source matches the resonant frequency of acetylene, the light source controller 11 also has a built-in superposition module. Step S410 specifically includes:

[0082] S411, The computing controller 7 transmits the modulation signal of the light source 1 to the lock-in amplifier 6;

[0083] S412, The lock-in amplifier 6 extracts the modulation parameters from the modulation signal of the light source 1 and sends them to the signal generator 8;

[0084] S413, The function generator 9 generates a reference signal and sends the reference signal to the buffer 10;

[0085] S414, the light source controller 11 receives the reference signal sent by the buffer 10 and the modulation signal of the light source 1 sent by the signal generator 8, and outputs them to the modulator 2 after superimposing them.

[0086] It is understandable that outputting the reference frequency in the buffer 10 to the superposition module can make the frequency in the modulation parameters consistent with the resonant frequency of the current resonant cavity 14. As a result, the laser generated by the light source component controlled by the second light source drive signal output according to the modulation parameters can produce a better photoacoustic effect, thereby improving the accuracy of the detection results.

[0087] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A rapid detection device for oil-soluble fault characteristic gases, characterized in that, The detection method based on photoacoustic spectroscopy includes: a photoacoustic cell and a light source assembly that emits laser light into the photoacoustic cell, wherein the light source assembly is controlled by a control assembly; The photoacoustic cell contains a cylindrical body, within which a resonant cavity is defined. The resonant cavity is connected to an air inlet window for introducing an oil-soluble gas containing a characteristic gas. The longitudinal section of the cylindrical body is a hyperbola, and the light source assembly emits laser light along the axial direction of the cylindrical body to operate at multiple frequencies. The control components include: a data acquisition unit, a lock-in amplifier, a computational controller, a function generator, a buffer, and a light source controller; The control component acquires the acoustic signal generated by the current photoacoustic effect in the photoacoustic cell to obtain the current concentration of the characteristic gas, and adjusts the laser output by the light source component according to the current concentration of the characteristic gas in the photoacoustic cell. This includes: the calculation controller outputs a light source parameter signal corresponding to the characteristic gas to the lock-in amplifier, the lock-in amplifier extracts the light source parameters from the light source parameter signal, and then transmits the light source parameters to the signal generator. The signal generator converts the light source parameters into a first light source drive signal that the light source controller can read, and outputs it to the light source controller. The light source controller adjusts the output of the light source component to the optimal laser signal absorbed by the characteristic gas according to the first light source drive signal. Furthermore, part of the laser signal injected into the photoacoustic cell is absorbed by the characteristic gas to produce a photoacoustic effect, and part of it is reflected by the mirror and re-enters the characteristic gas in the resonant cavity to produce a photoacoustic effect. After demodulating the acoustic signal, the lock-in amplifier calculates the concentration of the characteristic gas in the current oil-soluble gas and inputs it to the calculation controller; wherein, the function generator acquires the acoustic signal collected by the collector to obtain the resonant frequency of the current photoacoustic cell, outputs the resonant frequency as a reference frequency, so that the lock-in amplifier demodulates the acoustic signal output by the collector according to the reference frequency, and extracts the first information related to the concentration of the characteristic gas after demodulation; The first information is transmitted to the computing controller, which calculates the concentration of the characteristic gas based on the first information. The computing controller generates a light source modulation signal corresponding to the concentration of the characteristic gas. The light source controller controls the light source component according to the light source modulation signal to adjust the wavelength and amplitude of the laser to meet the resonant frequency inside the different resonant cavities required for different concentrations of the characteristic gas, so that it conforms to the current concentration of the characteristic gas.

2. The rapid detection device for oil-soluble fault characteristic gases according to claim 1, characterized in that, The resonant cavity has an axial length of 100 mm, the hyperbola has a minor axis of 2.5 mm, and the generatrix has an eccentricity of 7.14 mm.

3. The rapid detection device for oil-soluble fault characteristic gases according to any one of claims 1-2, characterized in that: The data acquisition unit is connected to the input terminal of the lock-in amplifier and the input terminal of the function generator, respectively. One output of the function generator is connected to the input of the buffer, and the other output is connected to the input of the lock-in amplifier. The computing controller and the lock-in amplifier are bidirectionally connected to each other to send signals. The output of the buffer is connected to one input of the light source controller, and the output of the lock-in amplifier is connected to the other input of the light source controller. The output of the light source controller is connected to the light source assembly.

4. A rapid detection method for characteristic gases of oil-soluble faults, characterized in that, Based on the rapid detection device for oil-soluble fault characteristic gases according to any one of claims 1-3, the control component performs the following steps: S100: The light source assembly emits a laser with set light source parameters into the photoacoustic cell, and introduces an oil-soluble gas containing the characteristic gas into the photoacoustic cell; S200, The collector collects the acoustic signal generated by the photoacoustic effect in the photoacoustic cell and transmits it to the lock-in amplifier and the function generator; S300. After the lock-in amplifier demodulates the acoustic signal, it calculates the concentration of the characteristic gas in the current oil-soluble gas and inputs it to the calculation controller. The calculation controller generates a light source modulation signal corresponding to the concentration of the characteristic gas. S400, The light source controller controls the light source component according to the light source modulation signal to adjust the laser so that it conforms to the current concentration of the characteristic gas.

5. The rapid detection method for oil-soluble fault characteristic gases according to claim 4, characterized in that, Specifically, S100 includes: S110. The oil-soluble gas containing the characteristic gas is introduced into the resonant cavity; S120. The light source parameter signal corresponding to the characteristic gas preset by the calculation controller is output to the lock-in amplifier. The lock-in amplifier extracts the light source parameters from the light source parameter signal and then transmits the light source parameters to the signal generator. S130, The signal generator converts the light source parameters into a first light source drive signal that the light source controller can read, and outputs it to the light source controller; S140, The light source controller adjusts the light source component according to the first light source driving signal.

6. The rapid detection method for oil-soluble fault characteristic gases according to claim 4, characterized in that, Specifically, S300 includes: S310. The function generator acquires the acoustic signal collected by the collector to obtain the current resonant frequency of the photoacoustic cell, outputs the resonant frequency as a reference frequency, so that the lock-in amplifier demodulates the acoustic signal output by the collector according to the reference frequency, and extracts the first information related to the concentration of the characteristic gas after demodulation. S320. The first information is transmitted to the computing controller, and the computing controller calculates the concentration of the characteristic gas based on the first information; S330. The calculation controller generates a light source modulation signal based on the calculated concentration of the characteristic gas, wherein the calculation controller is configured with a preset relationship between the concentration of the characteristic gas and the light source parameters.

7. The rapid detection method for oil-soluble fault characteristic gases according to claim 4, characterized in that, Specifically, S400 includes: S410. The computing controller transmits the light source modulation signal to the lock-in amplifier, the lock-in amplifier extracts the modulation parameters in the light source modulation signal, and then transmits them to the signal generator; S420, The signal generator converts the modulation parameters into a second light source drive signal that can be read by the light source controller, and the light source controller adjusts the light source component according to the second light source drive signal.

8. The rapid detection method for oil-soluble fault characteristic gases according to claim 7, characterized in that, S410 specifically includes: S411, The computing controller transmits the modulation signal of the light source to the lock-in amplifier; S412. The lock-in amplifier extracts the modulation parameters from the modulation signal of the light source and sends them to the signal generator; S413, The function generator generates a reference signal and sends the reference signal to the buffer; S414 The light source controller receives the reference signal sent by the buffer and the modulation signal of the light source sent by the signal generator, and outputs the result to the modulator.

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