Rapid detection device and method for oil-soluble fault characteristic gas

Abstract

The invention discloses a device and a method for rapidly detecting oil-soluble characteristic gas, the device comprises a photoacoustic cell and a light source assembly for emitting laser to the photoacoustic cell, and the light source assembly is controlled by a control assembly; the control assembly collects an acoustic signal of the current photoacoustic effect in the photoacoustic cell to obtain the current concentration of the characteristic gas, and the laser output by the light source assembly is adjusted according to the current concentration of the characteristic gas in the photoacoustic cell. Therefore, according to the device, dynamic adjustment of self-adaptive matching of the photoacoustic parameters and the gas concentration is realized through feedback adjustment, so that the accuracy of light source modulation can be ensured under different characteristic gas concentrations. Therefore, in the photoacoustic spectrometry detection process based on the method, the change of the concentration of the characteristic gas can be quickly responded, and the light source is matched with the current concentration of the characteristic gas, so that the detection accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of trace detection of power transformers, and particularly to a device and method for quickly detecting oil-soluble fault characteristic gases. Background Art

[0002] Power transformers are core equipment of the power grid, and their operating reliability affects the safety and stability of the power grid. Most transformer faults are gradually formed by internal local minor defects. The transformer is constructed as a fully enclosed box with a complex structure, and its internal defects are difficult to monitor through external measurement means. However, the resulting discharge or overheating phenomena will, to varying degrees, cause a series of chemical reactions in solid insulating materials such as transformer oil and insulating paper, generating different types of fault characteristic gases and dissolving them in the transformer oil. Just like the most common "blood test" method for diagnosing human diseases, by detecting or monitoring the concentration and ratio of dissolved characteristic gases in the oil, most internal hidden dangers and defects of the transformer can be discovered in a timely manner.

[0003] Currently, the photoacoustic spectroscopy method based on the photoacoustic effect is usually used to quickly detect the dissolved gases in transformer oil, so as to achieve early warning of transformer faults. During detection, for characteristic gases with different concentrations, corresponding light sources need to be modulated. However, the existing devices for detecting based on photoacoustic spectroscopy are difficult to quickly and accurately modulate a light source adapted to the concentration of characteristic gases, which affects the detection efficiency and results. Summary of the Invention

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

[0005] The purpose of the present invention is achieved through the following technical solutions: In a first aspect, the present application discloses a device for quickly detecting oil-soluble fault characteristic gases, including a photoacoustic cell and a light source assembly that emits laser light to the photoacoustic cell, and the light source assembly is controlled by a control component; a cylinder is constructed inside the photoacoustic cell, the cylinder defines a resonant cavity, and the resonant cavity is communicated with an air inlet window for introducing an oil-soluble gas containing characteristic gases; the control component collects the sound 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.

[0006] The beneficial effects are as follows: Compared with the traditional mode of static modulation of the light source, which has the defect of lag in the concentration response to the characteristic gas, this device realizes the dynamic adjustment of matching the parameters of the laser with the concentration of the characteristic gas by obtaining the concentration of the characteristic gas in real time and then feedback-adjusting the laser output by the light source component according to the gas concentration, so as to ensure the accuracy of light source modulation at different characteristic gas concentrations. In this way, on the premise of maintaining the stability of the resonant cavity, the response time of light source modulation can be shortened; and the synchronous closed-loop of concentration detection and light source modulation is realized, overcoming the problems of modulation delay and precision attenuation caused by the existing equipment relying on the empirical parameter library. Therefore, during the photoacoustic spectroscopy detection based on this method, it is possible to quickly respond to the change in the concentration of the characteristic gas to improve the detection sensitivity, and make the light source match the current concentration of the characteristic gas to improve the detection accuracy.

[0007] Preferably, the longitudinal section of the cylinder is a hyperbola, and the light source component emits laser along the axial direction of the cylinder.

[0008] The beneficial effects are as follows: A hyperbolic longitudinal section can achieve multi-frequency operation. Therefore, this resonant cavity can be used to implement the rapid detection method of oil-soluble characteristic gas in the above embodiments. Based on its characteristic of being able to operate at multiple frequencies, it can meet the different resonance frequencies inside the resonant cavity required according to different characteristic gas concentrations, so as to quickly respond to the change in the concentration of the characteristic gas in the resonant cavity.

[0009] Specifically, the axial length of the resonant cavity is 100 mm, the minor axis length of the hyperbola is 2.5 mm, and the eccentricity of the generatrix is 7.14 mm; and the size of 40 mm × 50 mm is symmetrically distributed by being connected by a waist-shaped resonant cavity.

[0010] Specifically, the control component includes: a collector, a lock-in amplifier, a calculation controller, a function generator, a buffer, and a light source controller; the collector is respectively connected to the input end of the lock-in amplifier and the input end of the function generator, one output end of the function generator is connected to the input end of the buffer, and the other output end is connected to the input end of the lock-in amplifier; the calculation controller is in two-way communication with the lock-in amplifier to send signals to each other; the output end of the buffer is connected to one input end of the light source controller, and the output end of the lock-in amplifier is connected to the other input end of the light source controller; the output end of the light source controller is connected to the light source component.

[0011] In a second aspect, the present application discloses a rapid detection method for oil-soluble characteristic gas, which is implemented based on the above rapid detection device for oil-soluble characteristic gas, and the control component executes the following steps: S100. The light source assembly emits laser with set light source parameters to 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, and 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 assembly according to the light source modulation signal to adjust the laser so that it conforms to the concentration of the current characteristic gas.

[0012] Its beneficial effects are as follows: Through the collaborative work of the lock-in amplifier and the calculation controller, the rapid response and detection of the characteristic gas are realized. Moreover, by accurately controlling the light source controller by the calculation controller and the lock-in amplifier, the laser conforming to parameters such as the current concentration and frequency of the characteristic gas is adjusted, effectively improving the reliability of the detection result and reducing the possibility of false alarms and missed alarms. The integration of the light source controller, the signal generator and the function generator enables the device to automatically adjust the modulation signal of the light source to adapt to the detection of characteristic gases with different concentrations, improving the convenience and automation level of operation.

[0013] Specifically, S100 specifically includes: S110. Introduce the oil-soluble gas containing the characteristic gas into the resonant cavity; S120. Output the light source parameter signal corresponding to the characteristic gas preset by the calculation controller to the lock-in amplifier, the lock-in amplifier extracts the light source parameters in 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 readable by the light source controller and outputs it to the light source controller; S140. The light source controller adjusts the light source assembly according to the first light source drive signal.

[0014] In some embodiments, the S300 specifically includes: S310, the function generator obtains the acoustic signal collected by the collector to obtain the resonance frequency of the current photoacoustic cell, outputs the resonance 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, transmits the first information to the calculation controller, and the calculation controller calculates the concentration of the characteristic gas according to the first information; S330, generates a light source modulation signal according to the calculated concentration of the characteristic gas. Among them, the calculation controller generates a light source modulation signal according to the calculated concentration of the characteristic gas. Among them, a preset relationship between the concentration of the characteristic gas and the light source parameters is set in the calculation controller.

[0015] Specifically, the S400 specifically includes: S410, the calculation controller transmits the light source modulation signal to the lock-in amplifier, and 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 readable by the light source controller to adjust the light source assembly according to the second light source drive signal. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a device for quickly detecting oil-soluble fault characteristic gases according to an embodiment of the present application; Figure 2 It is a flowchart of a method for quickly detecting oil-soluble fault characteristic gases according to an embodiment of the present application; Figure 3 It is a flowchart of a method for quickly detecting oil-soluble fault characteristic gases according to an embodiment of the present application; In the figure: 1 - Light source, 2 - Modulator, 3 - Collimator; 4 - Photoacoustic cell, 12 - Left gas chamber, 13 - Right gas chamber, 14 - Resonant cavity, 15 - Intake window, 16 - Exhaust window, 17 - Mirror, 18 - Microphone; 5 - Collector, 6 - Lock-in amplifier, 7 - Calculation controller, 8 - Signal generator, 9 - Function generator, 10 - Buffer, 11 - Light source controller. Detailed Embodiments

[0019] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0020] In the prior art, the dissolved characteristic gases in oil commonly used for judging whether a transformer is faulty mainly include seven kinds, namely hydrogen (H2), methane (CH4), ethane (C2H6), ethylene (C2H4), acetylene (C2H2), carbon monoxide (CO), and carbon dioxide (CO2). Among them, the detection of acetylene plays an important role in the detection of dissolved fault characteristic gases in transformer oil, and has important practical significance for the fault diagnosis, condition monitoring, and maintenance of transformers. Hereinafter, the detection of dissolved acetylene in oil will be taken as an example for illustration.

[0021] Referring to Figure 1 , the present invention provides a technical solution: a rapid detection device for oil-soluble characteristic gases, including: a photoacoustic cell 4 and a light source assembly that emits laser light to the photoacoustic cell 4, and the light source assembly is controlled by a control component; a cylinder body is constructed in the photoacoustic cell 4, the cylinder body defines a resonant cavity 14, and the resonant cavity 14 is communicated with an air inlet window 15 for introducing an oil-soluble gas containing characteristic gases. The oil-soluble gas can be a mixed gas (containing various characteristic gases) extracted from transformer oil, or an oil liquid dissolved with various characteristic gases. The control component collects the acoustic signal generated by the current photoacoustic effect in the photoacoustic cell 4 to obtain the current concentration of the characteristic gas. Here, the characteristic gas is acetylene. Of course, in different detection situations, it can also be other gases, which will not be elaborated here. The laser output by the light source assembly is adjusted according to the current concentration of the characteristic gas in the photoacoustic cell 4.

[0022] Specifically, when the characteristic gas enters the resonant cavity 14 of the photoacoustic cell 4, its molecules absorb the laser energy of a specific wavelength emitted by the laser to generate a thermal relaxation effect, and the intensity of the excited acoustic wave signal is positively correlated with the gas concentration, that is, 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 concentration of the characteristic gas, so that the laser emitted by the current light source 1 can be adapted to the specific concentration, which enables the light source to quickly respond to the concentration of the characteristic gas.

[0023] Therefore, compared with the traditional mode of static modulation of the light source, there is a lag defect in the concentration response to the characteristic gas. By obtaining the concentration of the characteristic gas in real time, and then adjusting the laser output by the light source component according to the gas concentration, the present device realizes the dynamic adjustment of matching the parameters of the laser with the concentration of the characteristic gas, so as to ensure the accuracy of modulating the light source 1 under different concentrations of the characteristic gas. In this way, on the premise of keeping the resonator 14 stable, the response time of modulating the light source 1 can be shortened; and the synchronization closed-loop of concentration detection and modulating the light source 1 is realized, overcoming the problems of modulation delay and accuracy attenuation caused by the existing equipment relying on the empirical parameter library.

[0024] Therefore, during the detection process of photoacoustic spectroscopy based on this method, it is possible to quickly respond to the change in the concentration of the characteristic gas, so as to improve the detection sensitivity, and make the light source 1 match the current concentration of the characteristic gas, so as to improve the detection accuracy.

[0025] Continue to refer to Figure 1 As shown, in some embodiments, the longitudinal section of the cylinder body provided in the photoacoustic cell 4 for defining the resonator 14 is a hyperbola, so that the resonator 14 is constructed into a waist-shaped structure, and the light source component emits laser along the axis direction of the cylinder body.

[0026] It should be noted that due to its own structure, the conventional cylindrical resonator has a limited frequency range that can be covered during the photoacoustic reaction. And because the natural frequency of the characteristic gas will change when the concentration of the characteristic gas changes, therefore, the conventional cylindrical resonator cannot achieve multi-frequency operation, resulting in its inapplicability to implement the above method and its poor detection sensitivity and stability.

[0027] Compared with the conventional resonator, the resonator 14 constructed with a hyperbola for the longitudinal section of the cylinder body and formed into a waist-shaped structure in the present application can cover a wider frequency range, that is, the resonator 14 in the device of the embodiment of the present application can achieve multi-frequency operation.

[0028] On this basis, the resonator 14 that can achieve multi-frequency can be used to implement the rapid detection method of the oil-soluble characteristic gas in the above embodiment, based on its characteristic of being able to perform multi-frequency operation, to meet the different resonance frequencies inside the resonator 14 required according to different concentrations of the characteristic gas; thus quickly responding to the change in the concentration of the characteristic gas in the resonator 14.

[0029] Moreover, compared with the conventional cylindrical resonator, the waist-shaped resonator 14 also has better sensitivity and anti-interference ability.

[0030] In a preferred example, the axial length of the resonant cavity 14 is 100 mm, and the hyperbola in the longitudinal section is a resonant cavity 14 with a minor axis length of 2.5 mm and a busbar of a hyperbola with an eccentricity of 7.14 mm; defining the resonant cavity 14 as the above structure can obtain better test results.

[0031] 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 calculation controller 7, a function generator 9, a buffer 10, and a light source controller 11.

[0032] The light source 1 is connected to the modulator 2, the modulator 2 is connected to the collimator 3, and the collimator 3 is installed at one end of the photoacoustic cell 4; the collector 5 is connected to the input end of the lock-in amplifier 6 and the input end of the function generator 9. One output end of the function generator 9 is connected to the input end of the buffer 10, and the other output end is connected to the input end of the lock-in amplifier 6; the calculation controller 7 is in two-way communication with the lock-in amplifier 6 to send signals to each other; the output end of the buffer 10 is connected to one input end of the light source controller 11, and the output end of the lock-in amplifier 6 is connected to the other input end of the light source controller 11; the output end of the light source controller 11 is connected to the light source assembly.

[0033] The light source 1 provides an optical signal. For example, the light source 1 is a laser. The coherence of the laser makes the photoacoustic signal easier to be detected and demodulated by the lock-in amplifier 6. The emitted optical signal can be precisely controlled by an electronic control device. Combined with the light source controller 11, precise modulation of the laser output can be achieved.

[0034] The modulator 2 converts the control signal output by the light source controller 11 into an optical signal and modulates the optical signal emitted by the light source 1 into the best signal absorbed by acetylene gas. For example, the modulator 2 is a mechanical chopper. Using a mechanical chopper in the 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 light of other frequencies.

[0035] The collimator 3 collimates the divergent light into an approximately parallel beam with a very small divergence angle to improve the coupling efficiency of the optical signal emitted by the light source 1. For example, the collimator is an optical fiber collimator. In a scenario with higher requirements, the optical fiber collimator has the ability to resist backlight and can withstand a higher output power, which is particularly important for high-power beams that may be encountered in photoacoustic spectroscopy detection.

[0036] 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 mirror 17, and a microphone 18; the left gas chamber 12 is provided with the air inlet window 15, and the dissolved gas in the transformer oil enters the resonant cavity 14 of the photoacoustic cell 4 after buffering in the left gas chamber 12; the right gas chamber 13 is provided with the exhaust window 16, and the dissolved acetylene gas in the transformer oil is discharged from the photoacoustic cell 4 after buffering in the right gas chamber 13. In this example, for the air inlet window 15, the dissolved acetylene gas in the transformer oil enters the left gas chamber 12 from the transformer oil through the air inlet window 15; for the exhaust window 16, the acetylene gas is discharged to the air or a specific unit through the exhaust window 16, and the left gas chamber 12 and the right gas chamber 13 are preferably symmetrically distributed with a size of 40mm×40mm×50mm and connected by a waist-shaped resonant cavity 14, reducing the interference of the detection result and improving the stability of the detection.

[0037] The microphone 18 converts the acoustic signal generated by the photoacoustic effect into an electrical signal that can be collected by the collector 5 and is collected by the collector 5. For example, the microphone 18 is a piezoelectric microphone, which has the advantages of high sensitivity, fast response, and wide-band response.

[0038] Next, the present application discloses a method for quickly detecting oil-soluble characteristic gases. For better illustration, taking the process of implementing this method by combining with the above-mentioned device for quickly detecting oil-soluble fault characteristic gases as an example, refer to Figures 1 - 3 For understanding, the method for quickly detecting oil-soluble fault characteristic gases includes: the control component executes the following steps: S100. The light source component emits a laser with set light source parameters to the photoacoustic cell 4 and introduces an oil-soluble gas containing acetylene gas into the photoacoustic cell 4.

[0039] Specifically, it includes: S110. The gas dissolved in the transformer oil is introduced into the resonant cavity 14. The gas contains acetylene gas. After the gas enters the left gas chamber 12 of the photoacoustic cell 4 from the air inlet window 15, it then enters the resonant cavity 14 of the photoacoustic cell 4 and fills the right gas chamber 13 of the photoacoustic cell 4 as the gas diffuses.

[0040] S120. Output the light source parameter signal corresponding to acetylene gas preset by the calculation controller 7 to the lock-in amplifier 6. The lock-in amplifier 6 extracts the light source parameters in the light source parameter signal and then transmits the light source parameters to the signal generator 8.

[0041] S130. The signal generator 8 converts the light source parameters into a light source drive signal readable by the light source controller 11. Here, in order to distinguish it from the following text, this light source drive signal is defined as the first light source drive signal and is output to the light source controller 11.

[0042] 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 by the light source 1 into the 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 collimation by the collimator 3, it becomes an approximate parallel beam with a very small divergence angle and is incident into the photoacoustic cell 4.

[0043] It can be understood that the laser signal output in the above manner is to generate a repetitive photoacoustic effect in the photoacoustic cell 4. That is, when there is acetylene gas in the dissolved gas of the transformer, a part of the laser signal incident into the photoacoustic cell 4 is absorbed by the acetylene gas, generating a photoacoustic effect, and a part is reflected by the mirror 17 and then enters the resonant cavity 14 again to generate a photoacoustic effect with the acetylene gas.

[0044] S200. The collector 5 collects the acoustic signal generated by the photoacoustic effect in the photoacoustic cell 4. Specifically, the collector 5 is the 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 collector 5 collects the electrical signal converted and transmitted by the microphone 18 and inputs it into the lock-in amplifier 6 and the function generator 9.

[0045] S300. After the lock-in amplifier 6 demodulates the acoustic signal, it calculates the current concentration of acetylene gas and inputs it into the calculation controller 7. The calculation controller 7 generates a modulation signal for the light source 1 corresponding to the concentration of the characteristic gas. Specifically, it includes: S310. The function generator 9 obtains the acoustic signal collected by the collector 5 to obtain the resonance frequency of the photoacoustic cell 4, and outputs the resonance frequency as the reference frequency. That is, the reference frequency is the same as the resonance frequency of the photoacoustic cell 4, so that the lock-in amplifier 6 demodulates the acoustic signal output by the collector 5. After the lock-in amplifier 6 demodulates the acoustic signal by photoacoustic spectroscopy, it extracts information related to the concentration of acetylene gas, such as: Fourier transform of sound pressure, sound speed, etc. Here, for better distinction, the information related to the concentration of acetylene gas is defined as the first information.

[0046] S320. Transmit the first information to the calculation controller 7. The calculation controller 7 calculates the concentration of acetylene gas. Specifically, preferably, the active Helmholtz equation can be used to calculate the change in sound pressure in the photoacoustic cell 4, which is expressed by the following formula: In the formula: represents the Fourier transform of sound pressure; k represents a coefficient, which is expressed by the following formula In the formula: v represents the speed of sound; QUOTE represents the specific heat capacity at constant pressure QUOTE and the specific heat capacity at constant volume QUOTE ratio.

[0047] Since the absorption transition of gas molecules in the cavity is unsaturated, and the modulation frequency of the laser heat source is much smaller than the relaxation rate of the gas molecule transition, the heat source is given by the following formula: where: represents the light intensity of the laser incident on the photoacoustic cell; α represents the absorption coefficient of the gas in the cell; QUOTE represents the total molecular number density of the gas in the cell; QUOTE represents the absorption cross section of the gas molecules in the cell; QUOTE represents the volume concentration of acetylene gas; QUOTE the output power of the laser; QUOTE represents the normalized function of the light energy distribution.

[0048] It can be understood that after the device executes the above steps, through the coordinated work of the lock-in amplifier 6 and the calculation controller 7, the rapid response and detection of acetylene gas are realized, thereby making the detection efficiency better.

[0049] S330. The calculation controller 7 generates a modulation signal for the light source 1 according to the calculated acetylene concentration. Specifically, a preset relationship between the acetylene concentration and the parameters of the light source 1 is set in the calculation controller 7. According to 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 be converted into a modulation signal for the light source 1, or after encoding, digital-to-analog conversion is performed to convert it into an analog signal, etc.

[0050] 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 they conform to the concentration of the current characteristic gas.

[0051] Specifically, it includes: S410. The calculation 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, both the modulation parameters and the light source parameters mentioned above can include the wavelength, amplitude, etc. of the light source.

[0052] S420. The signal generator 8 converts the modulation parameters into a light source drive signal readable by the light source controller 11. To distinguish it from the above, this light source drive signal is defined as the second light source drive signal here. 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 better conforms to the concentration of the current characteristic gas.

[0053] It can be understood that the integration of the light source controller 11, the signal generator 8, and the function generator 9 enables the device to automatically adjust the modulation signal of the light source to adapt to the detection of acetylene with different concentrations, improving the convenience and automation level of operation. And since the light source conforms to the current acetylene concentration, the reliability of the detection result is also improved, reducing the possibility of false alarms and missed reports.

[0054] To ensure that the frequency of the light source conforms to the resonance frequency of acetylene, the light source controller 11 also has a superimposing module built in. Step S410 specifically includes: S411. The calculation controller 7 transmits the modulation signal of the light source 1 to the lock-in amplifier 6. S412. The lock-in amplifier 6 extracts the modulation parameters in the modulation signal of the light source 1 and sends them to the signal generator 8. S413. The function generator 9 generates a reference signal and sends the reference signal to the buffer 10. 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, superimposes them, and then outputs them to the modulator 2.

[0055] It can be understood that outputting the reference frequency in the buffer 10 to the superimposing module can make the frequency in the modulation parameters consistent with the resonance frequency in the current resonant cavity 14. Thus, the laser generated by the light source assembly 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 result.

[0056] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept described herein through the above teachings or the techniques or knowledge in related fields. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A rapid detection device for oil-soluble fault characteristic gases, characterized in that Comprising: A photoacoustic cell and a light source assembly for emitting laser light to the photoacoustic cell, the light source assembly being controlled by a control assembly; A cylinder is constructed inside the photoacoustic cell, a resonance cavity is defined inside the cylinder, and the resonance cavity is communicated with an intake window for introducing an oil-soluble gas containing a characteristic gas; The control assembly collects 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.

2. The rapid detection device for oil-soluble fault characteristic gas according to claim 1, characterized in that The longitudinal section of the cylinder is a hyperbola, and the light source assembly emits laser light along the axis direction of the cylinder.

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

4. The rapid detection device for oil-soluble fault characteristic gases according to any one of claims 1 to 3, characterized in that, The control assembly includes: a collector, a lock-in amplifier, a calculation controller, a function generator, a buffer, and a light source controller; The collector is respectively connected to the input end of the lock-in amplifier and the input end of the function generator; One output end of the function generator is connected to the input end of the buffer, and the other output end is connected to the input end of the lock-in amplifier; The calculation controller is in two-way communication with the lock-in amplifier to send signals to each other; The output end of the buffer is connected to one input end of the light source controller, and the output end of the lock-in amplifier is connected to the other input end of the light source controller; The output end of the light source controller is connected to the light source assembly.

5. A method for quickly detecting oil-soluble fault characteristic gases, characterized in that, Implemented based on the rapid detection device for oil-soluble fault characteristic gas according to claim 4, the control assembly performs the following steps: S100. The light source assembly emits laser light with set light source parameters to 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 and obtains the concentration of the characteristic gas in the current oil-soluble gas and inputs it to the calculation controller, and 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 assembly according to the light source modulation signal to adjust the laser light so that it conforms to the current concentration of the characteristic gas.

6. The rapid detection method of oil-soluble fault characteristic gas according to claim 5, characterized in that The S100 specifically includes: S110. Introduce the oil-soluble gas containing the characteristic gas into the resonance cavity; S120. Output the light source parameter signal corresponding to the characteristic gas preset by the calculation controller to the lock-in amplifier, the lock-in amplifier extracts the light source parameters in 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 readable by the light source controller and outputs it to the light source controller; S140. The light source controller adjusts the light source assembly according to the first light source drive signal.

7. The rapid detection method of oil-soluble fault characteristic gas according to claim 5, characterized in that The S300 specifically includes: S310. The function generator obtains the acoustic signal collected by the collector to obtain the resonance frequency of the current photoacoustic cell, and outputs the resonance 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. Transmit the first information to the calculation controller, and the calculation controller calculates the concentration of the characteristic gas according to the first information; S330. The calculation controller generates a light source modulation signal according to the calculated concentration of the characteristic gas. Among them, a preset relationship between the concentration characteristic gas of the characteristic gas and the light source parameters is set in the calculation controller.

8. The rapid detection method of oil-soluble fault characteristic gas according to claim 5, characterized in that, The S400 specifically includes: S410. The calculation controller transmits the light source modulation signal to the lock-in amplifier, and the lock-in amplifier extracts the modulation parameter in the light source modulation signal and then transmits it to the signal generator; S420. The signal generator converts the modulation parameter into a second light source drive signal readable by the light source controller, and the light source controller adjusts the light source assembly according to the second light source drive signal.

9. The rapid detection method of oil-soluble fault characteristic gas according to claim 8, characterized in that, The S410 specifically includes: S411. The calculation controller transmits the modulation signal of the light source to the lock-in amplifier; S412. The lock-in amplifier extracts the modulation parameter in the modulation signal of the light source and sends it 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, superimposes them and outputs them to the modulator.

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