Oil-gas detection device for oil-immersed equipment

Abstract

The present application discloses an oil and gas detection device for oil-immersed equipment, comprising: a measuring unit, used to use a narrow-bandwidth laser to respectively measure a first photoacoustic signal intensity of a characteristic gas in a gas sample to be tested, and a second photoacoustic signal intensity of a characteristic gas in a standard gas sample; a control unit, used to obtain the actual concentration of the characteristic gas in the gas sample to be tested according to the second photoacoustic signal intensity, the standard photoacoustic signal intensity and the first photoacoustic signal intensity, and determine the operating fault type of the oil-immersed equipment according to the actual concentration; when the present application detects that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity, the preset power of the narrow-bandwidth laser can be corrected to obtain the actual concentration of the characteristic gas in the gas sample to be tested, and the fault type of the oil-immersed equipment can be judged according to characteristics such as the component type and actual concentration of the characteristic gas in the gas sample to be tested, with high detection efficiency and accuracy.

Description

Technical Field

[0001] The present application relates to the field of oil-immersed equipment detection, and in particular to an oil and gas detection device for oil-immersed equipment. Background Art

[0002] With the rapid development of the national economy, the demand for electricity in all walks of life continues to rise. Nowadays, the power system is also developing towards ultra-high voltage, large capacity and automation. Therefore, a large number of large oil-immersed equipment (such as transformers) are used in the power system. In order to ensure the safe operation of the power system, the operating status of large oil-immersed equipment such as transformers must be preventively inspected and monitored.

[0003] Since oil-immersed equipment uses composite insulation structures such as cooling oil, oil paper or oil paperboard, when thermal faults, discharge faults or aging of the insulating oil or oil paper occur inside the equipment, various gases will be produced. These gases will dissolve in the cooling oil. The different types of gases dissolved in the cooling oil can reflect different types of electrical faults in the oil-immersed equipment.

[0004] At present, in the traditional operating status monitoring scheme of oil-immersed equipment, it is necessary to manually extract oil samples from the oil-immersed equipment and concentrate them in the laboratory, and then use gas chromatograph to analyze the oil samples. The operating status of the oil-immersed equipment is determined based on the analysis results, which is inefficient. Summary of the invention

[0005] An embodiment of the present application provides an oil and gas detection device for oil-immersed equipment to solve the technical problem of low efficiency in the existing traditional oil-immersed equipment operation status monitoring solution, which requires manual extraction of oil samples from the oil-immersed equipment and concentration in the laboratory, and then analysis of the oil samples using a gas chromatograph to determine the operation status of the oil-immersed equipment based on the analysis results.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] An oil-gas detection device for oil-immersed equipment comprises a control unit, an oil circuit unit, a degassing unit, a gas circuit unit and a measuring unit, wherein:

[0008] The control unit is used to send a sampling enable signal, a degassing enable signal, and a measurement enable signal;

[0009] The oil circuit unit is used to receive the sampling enable signal and the degassing enable signal, and the oil circuit unit is also used to obtain a cooling oil sample from the oil-immersed device according to the sampling enable signal, and control the cooling oil sample to flow into the degassing unit according to the degassing enable signal;

[0010] The degassing unit is used to receive the degassing enable signal and the measurement enable signal, and the degassing unit is also used to degas the cooling oil sample according to the degassing enable signal to obtain the gas sample to be tested, and control the gas sample to be tested to flow into the gas circuit unit according to the measurement enable signal;

[0011] The gas circuit unit is used to receive the measurement enable signal and control the gas sample to be measured to flow from the gas circuit unit into the measurement unit according to the measurement enable signal;

[0012] The measuring unit is used to receive the measurement enable signal, and the measuring unit is also used to control the photoacoustic spectrometer in the measuring unit to use a narrow bandwidth laser with a preset power and a preset wavelength to respectively measure a first photoacoustic signal of a characteristic gas in the gas sample to be measured and a second photoacoustic signal of a characteristic gas in a standard gas sample according to the measurement enable signal, and feed back the first photoacoustic signal and the second photoacoustic signal to the control unit;

[0013] The control unit is further used to determine a first photoacoustic signal intensity of a characteristic gas in the gas sample to be measured and a second photoacoustic signal intensity of a characteristic gas in a standard gas sample according to the first photoacoustic signal and the second photoacoustic signal, and to obtain an actual concentration of the characteristic gas in the gas sample to be measured according to the second photoacoustic signal intensity, the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample, and the first photoacoustic signal intensity;

[0014] The control unit is further configured to determine an operating fault type of the oil-immersed device according to the actual concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0016] Figure 1 A schematic diagram of a scenario of an oil-immersed equipment monitoring system provided in an embodiment of the present application;

[0017] Figure 2 A schematic diagram of the first structure of the oil and gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0018] Figure 3 A second structural schematic diagram of the oil and gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0019] Figure 4 A schematic diagram of a first structure of a measurement unit provided in an embodiment of the present application;

[0020] Figure 5 is a schematic diagram of the structure of a temperature control unit provided in an embodiment of the present application;

[0021] Figure 6 is a schematic diagram of a temperature control circuit in a temperature control unit provided in an embodiment of the present application;

[0022] Figure 7 A second structural schematic diagram of a measurement unit provided in an embodiment of the present application;

[0023] Figure 8 A third structural schematic diagram of a measurement unit provided in an embodiment of the present application;

[0024] Fig. 9 A circuit schematic diagram of a photoelectric conversion circuit of an oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0025] Fig.10 A circuit schematic diagram of a first signal amplifying circuit of an oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0026] Fig.11 A circuit schematic diagram of a bandpass filter circuit of an oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0027] Fig.12 A circuit schematic diagram of a second signal amplifying circuit of an oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0028] Fig.13 A circuit schematic diagram of an A / D conversion circuit of an oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application;

[0029] Fig.14 A third structural schematic diagram of the oil and gas detection device for oil-immersed equipment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0031] The present application aims to address the technical problem of low efficiency in the existing traditional operating status monitoring scheme for oil-immersed equipment, which requires manual extraction of oil samples from the oil-immersed equipment and concentration in the laboratory, and then analysis of the oil samples using a gas chromatograph to determine the operating status of the oil-immersed equipment based on the analysis results.

[0032] See also Figure 1 , Figure 1A scenario diagram of an oil-immersed equipment operation status monitoring system provided in an embodiment of the present application, the system may include an oil-immersed equipment 10 and an oil-gas detection device 20 for the oil-immersed equipment, and the oil-immersed equipment oil-gas detection device 20 may be connected to the oil-immersed equipment 10 via a pipeline.

[0033] The oil-immersed device 10 may be an oil-filled transformer, and the internal insulation structure of the oil-filled transformer is a composite insulation structure mainly composed of cooling oil and insulating material, and the insulating material may be one or more of insulating paper and insulating board.

[0034] Among them, the cooling oil is generally a mixture of various hydrocarbon molecules, and the cooling oil can be composed of a large part of calcined hydrocarbons and a small part of cyclocalcined hydrocarbons and unsaturated aromatic hydrocarbons; the insulating paper or insulating board can be a fiber product, and the main component of the insulating paper or insulating board is cellulose. When a fault such as discharge or overheating occurs inside the oil-filled transformer, the high-carbon organic molecules in the insulating material are cracked to produce characteristic gases such as methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide and hydrogen, and the generated characteristic gases will continue to accumulate in the cooling oil of the oil-immersed device 10.

[0035] Specifically, Figure 1 and Figure 2 As shown, Figure 2 This is a first structural schematic diagram of an oil-immersed equipment oil and gas detection device 20 provided in an embodiment of the present application, wherein the oil-immersed equipment oil and gas detection device 20 includes an oil circuit unit 201, a degassing unit 202, a gas circuit unit 203, a measuring unit 204 and a control unit 205.

[0036] Specifically, the control unit 205 is used to send a sampling enable signal to the oil circuit unit 201, send a degassing enable signal to the oil circuit unit 201 and the degassing unit 202, and send a measurement enable signal to the degassing unit 202, the gas circuit unit 203 and the measuring unit 204, thereby controlling the operation of the oil circuit unit 201, the degassing unit 202, the gas circuit unit 203 and the measuring unit 204.

[0037] Specifically, the oil circuit unit 201 is used to receive the sampling enable signal and the degassing enable signal. The oil circuit unit 201 is also used to obtain a cooling oil sample from the oil-immersed device 10 according to the sampling enable signal, and control the cooling oil sample to flow into the degassing unit 202 according to the degassing enable signal.

[0038] In one embodiment, when the oil circuit unit 201 obtains the cooling oil sample from the oil-immersed device 10, a valve and an oil pump can be set between the oil-immersed device 10 and the oil circuit unit 201. When the control unit 205 sends a sampling enable signal to the oil circuit unit 201, the valve between the oil circuit unit 201 and the oil-immersed device 10 is opened, and the oil pump draws the cooling oil sample from the oil-immersed device 10 into the oil circuit unit 201. The volume of the cooling oil sample is set according to demand.

[0039] In one embodiment, after the oil circuit unit 201 obtains the cooling oil sample, the cooling oil sample can be pre-processed in the oil circuit unit 201. For example, if there are impurities such as organic particles or water in the cooling oil sample, the organic particles or water in the cooling oil sample are removed during the pre-processing process, so that the pre-treated cooling oil sample is relatively pure.

[0040] Specifically, the degassing unit 202 is used to receive the degassing enable signal and the measurement enable signal. The degassing unit 202 is also used to degas the cooling oil sample according to the degassing enable signal to obtain the gas sample to be tested, and control the gas sample to be tested to flow into the gas path unit 203 according to the measurement enable signal.

[0041] The oil circuit unit 201 and the degassing unit 202 may be connected via an oil pipe, and a valve is provided on the oil pipe to control the connection and disconnection between the oil circuit unit 201 and the degassing unit 202 .

[0042] In one embodiment, when the degassing unit 202 is used to degas the cooling oil sample, the cooling oil sample may be degassed by head space degassing or by using a degassing membrane tube.

[0043] Among them, the headspace degassing method refers to the cooling oil sample entering the oil tank and discharging the gas above the oil tank to avoid the original gas in the oil tank from affecting the gas sample to be tested, so that a negative pressure is formed in the oil tank, and then the bottom of the oil tank is heated and the cooling oil sample is stirred at the same time to separate the gas sample to be tested in the cooling oil.

[0044] The degassing method using a degassing membrane tube means first extracting the gas in the degassing membrane tube to prevent the original gas in the degassing membrane tube from affecting the gas sample to be tested in the cooling oil sample, and forming a negative pressure in the degassing membrane tube, and then allowing the cooling oil sample to enter the degassing membrane tube. A polytetrafluoroethylene nano-separation membrane is provided in the degassing membrane tube, and the polytetrafluoroethylene nano-separation membrane is used to separate the gas sample to be tested in the cooling oil sample.

[0045] Specifically, the gas circuit unit 203 is used to receive the measurement enable signal, and the gas circuit unit 203 is also used to control the gas sample to be measured to flow from the gas circuit unit 203 to the measurement unit 204 according to the measurement enable signal.

[0046] In one embodiment, the gas circuit unit 203 may include a pipeline and a filter-drying component, and the degassing unit 202 and the measuring unit 204 may be connected through the pipeline in the gas circuit unit 203; when the gas sample to be tested enters the gas circuit unit 203 from the degassing unit 202, the gas sample to be tested may contain impurity gases such as water vapor, and the gas sample to be tested may be pre-treated in the gas circuit unit 203 through the filter-drying component to remove the impurity gases in the gas sample to be tested.

[0047] Specifically, the measuring unit 204 is used to receive the measurement enable signal, and the measuring unit 204 is also used to control the photoacoustic spectrometer in the measuring unit 204 according to the measurement enable signal to use a narrow bandwidth laser with a preset power and a preset wavelength to respectively measure the first photoacoustic signal of the characteristic gas in the gas sample to be measured and the second photoacoustic signal of the characteristic gas in the standard gas sample, and to feed back the first photoacoustic signal and the second photoacoustic signal to the control unit 205.

[0048] Specifically, the control unit 205 is further configured to determine a first photoacoustic signal intensity of a characteristic gas in the gas sample to be tested and a second photoacoustic signal intensity of a characteristic gas in a standard gas sample according to the first photoacoustic signal and the second photoacoustic signal.

[0049] Wherein, the narrow bandwidth laser is a laser that has been periodically intensity modulated or periodically frequency modulated, the narrow bandwidth laser has a preset wavelength corresponding to the characteristic gas, and the narrow bandwidth laser is monochromatic light; the characteristic gas can be any one of methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide and hydrogen. When measuring the gas sample to be measured, it is necessary to measure the concentration of all types of characteristic gases in the gas sample to be measured; the standard gas sample includes gases such as methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide and hydrogen, and the sample standard concentration of the characteristic gas in the standard gas sample is a known concentration.

[0050] It should be noted that photoacoustic spectroscopy is a spectral technology that uses the photoacoustic effect to detect the concentration of absorbents. Photoacoustic spectroscopy is based on the principle of photoacoustic effect, that is, the principle that a substance will generate an acoustic signal when it is irradiated with periodic intensity modulated light or periodic frequency modulated light. The specific principle of the photoacoustic effect is: the characteristic gas molecules in the gas sample to be tested are excited to a high energy state after absorbing the narrow bandwidth laser of the corresponding wavelength, and the characteristic gas molecules return to a low energy state through spontaneous radiation transition and non-radiative transition. In the process of non-radiative transition back to the low energy state, the energy released by the characteristic gas molecules is converted into the translational and rotational kinetic energy of the gas sample to be tested, resulting in an increase in the temperature of the gas sample to be tested. Under the condition that the gas volume of the gas sample to be tested is constant, the temperature of the gas sample to be tested increases, and the gas pressure of the gas sample to be tested increases. If the narrow bandwidth laser is subjected to light intensity modulation or frequency modulation, the temperature of the gas sample to be tested will show the same periodic change as the modulation frequency, which in turn causes the pressure of the gas sample to be tested to change periodically. When the modulation frequency is within the acoustic frequency range, a sound signal, namely a photoacoustic signal, is generated.

[0051] It is understandable that among characteristic gases such as methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide and hydrogen, each gas molecule has its own absorption band and absorption peak, and there are certain differences in the absorption peaks of different gases.

[0052] Therefore, when using the oil-immersed equipment oil and gas detection device 20 to detect the gas dissolved in the cooling oil of the oil-immersed equipment 10, the wavelength of the narrow-bandwidth laser can be adjusted so that the narrow-bandwidth laser is only absorbed by the corresponding characteristic gas in the gas sample to be tested, so as to achieve separate detection of characteristic gases such as methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide and hydrogen in the gas sample to be tested, thereby detecting the component type of the characteristic gas in the gas sample to be tested.

[0053] When the power and wavelength of the narrow-bandwidth laser remain unchanged, the intensity of the photoacoustic signal generated by the characteristic gas is proportional to the concentration of the characteristic gas, so that the concentration of the characteristic gas in the gas sample to be tested can be detected, and the fault nature and fault type of the oil-immersed device 10 can be judged according to the characteristics such as the component type and concentration of the characteristic gas in the gas sample to be tested, so as to realize real-time monitoring of oil-immersed devices 10 such as oil-filled transformers, with high detection efficiency, and timely discovery of internal faults of oil-immersed devices 10 such as oil-filled transformers. For example, during the epidemic, the oil-immersed device oil and gas detection device 20 can be used to monitor the oil-immersed device 10 in real time and effectively, without the need for the staff to regularly extract oil samples from the oil-immersed device 10 and use a gas chromatograph to analyze the oil samples in the laboratory, thereby reducing the labor intensity and work risks of the staff; at the same time, when the oil-immersed device 10 fails, the oil-immersed device oil and gas detection device 20 can promptly detect the fault type of the oil-immersed device 10 and send an alarm to the staff, so that the staff can handle the oil-immersed device 10 according to the fault type.

[0054] As shown in Table 1 below, Table 1 shows the types of characteristic gases corresponding to each fault type.

[0055]

[0056]

[0057] Table 1

[0058] It can be seen from Table 1 that when the oil-immersed equipment 10 has different fault types, the types of characteristic gases measured from the gas sample to be tested are different. For example, when the fault type is cooling oil overheating, the corresponding characteristic gas types are hydrogen, ethylene, methane and ethane; when the fault type is cooling oil and paper overheating, the corresponding characteristic gas types are hydrogen, carbon monoxide, carbon dioxide, ethylene, methane, and ethane; when the fault type is cooling oil and partial discharge in paper insulation, the corresponding characteristic gas types are hydrogen, carbon monoxide, carbon dioxide, ethylene, methane, and ethane. Acetylene, methane, ethane; when the fault type is spark discharge in the cooling oil, the corresponding characteristic gases are hydrogen and acetylene; when the fault type is arc discharge in the cooling oil, the corresponding characteristic gases are hydrogen, acetylene, ethylene, methane and ethane; when the fault type is arc discharge in the cooling oil and paper, the corresponding characteristic gases are hydrogen, carbon monoxide, carbon dioxide, acetylene, ethylene, methane and ethane; when the fault type is damp paper or bubbles in the cooling oil, the corresponding characteristic gas is hydrogen; "-" in Table 1 indicates that the concentration of the characteristic gas in this fault type is 0.

[0059] It can be understood that the concentration of the characteristic gas in the gas sample to be tested refers to the mass number of the characteristic gas in the standard volume of the gas sample to be tested.

[0060] Specifically, the control unit 205 is also used to obtain the actual concentration of the characteristic gas in the gas sample to be tested based on the second photoacoustic signal intensity, the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample, and the first photoacoustic signal intensity, and determine the operating fault type of the oil-immersed equipment 10 based on the actual concentration.

[0061] It should be noted that, when the wavelength of the narrow-bandwidth laser and the concentration of the characteristic gas remain unchanged, the intensity of the photoacoustic signal generated by the characteristic gas is linearly related to the power of the narrow-bandwidth laser. However, due to factors such as equipment aging, the power of the narrow-bandwidth laser used by the photoacoustic spectrometer in the measuring unit 204 during the monitoring process may attenuate, causing the actual power of the narrow-bandwidth laser to be different from the preset power, thereby causing the detected first photoacoustic signal intensity to be less than the accurate first photoacoustic signal intensity, resulting in the measured concentration of the characteristic gas in the gas sample to be tested determined based on the first photoacoustic signal intensity to be less than the actual concentration, affecting the fault judgment result of the oil and gas detection device 20 for the oil-immersed equipment 10.

[0062] In the present application, the gas sample to be tested and the standard gas sample are detected simultaneously in the photoacoustic spectroscopic device. Since the type and concentration of the characteristic gas in the standard gas sample are determined, the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample can be calculated when the power and wavelength of the narrow-bandwidth laser used in the photoacoustic spectroscopic device are determined. When it is detected that the second photoacoustic signal intensity of the characteristic gas in the standard gas sample is different from the standard photoacoustic signal intensity, it can be determined that the preset power of the narrow-bandwidth laser used in the photoacoustic spectroscopic device is different from the actual power. At this time, by correcting the preset power of the narrow-bandwidth laser to change the actual power of the narrow-bandwidth laser, the actual concentration of the characteristic gas in the gas sample to be tested can be obtained, thereby improving the detection precision and accuracy of the oil and gas detection device 20 for oil-immersed equipment.

[0063] It should be noted that when obtaining the actual concentration of the characteristic gas in the gas sample to be tested, it is necessary to determine whether the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity; if they are the same, the control unit 205 can determine the measured concentration of the characteristic gas in the gas sample to be tested corresponding to the first photoacoustic signal intensity based on the correspondence between the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity, and obtain the actual concentration. At this time, the measured concentration is the same as the actual concentration.

[0064] When it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity, the measured concentration of the characteristic gas in the gas sample to be tested corresponding to the first photoacoustic signal intensity is different from the actual concentration. At this time, the oil-immersed equipment oil and gas detection device 20 has an error in the fault detection of the oil-immersed equipment 10, and the detection result needs to be corrected to obtain the actual concentration of the characteristic gas in the gas sample to be tested.

[0065] In one embodiment, the control unit 205 is also used to determine the photoacoustic signal intensity attenuation value caused by the power attenuation of the narrow-bandwidth laser at the standard concentration of the sample based on the second photoacoustic signal intensity and the standard photoacoustic signal intensity when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample.

[0066] The control unit 205 is further configured to determine the narrow bandwidth laser power attenuation value according to the corresponding relationship among the gas concentration, the narrow bandwidth laser power attenuation value and the photoacoustic signal intensity attenuation value.

[0067] The control unit 205 is further configured to send a correction enable signal to the measurement unit 204 according to the narrow bandwidth laser power attenuation value.

[0068] The measuring unit 204 is further configured to modify the preset power according to the modification enable signal.

[0069] The measuring unit 204 is further used to control the photoacoustic spectrometer to re-measure the characteristic gas in the gas sample to be measured using a narrow-bandwidth laser with a corrected preset power to obtain an actual photoacoustic signal intensity of the characteristic gas in the gas sample to be measured.

[0070] The control unit 205 is further configured to determine the actual concentration corresponding to the actual photoacoustic signal intensity according to the corresponding relationship among the gas concentration, the narrow bandwidth laser power and the photoacoustic signal intensity.

[0071] It should be noted that the sample standard concentration refers to the concentration of the characteristic gas in the standard gas sample. The sample standard concentration is a known concentration and is greater than the minimum concentration that can be measured by the measurement unit 204. The sample standard concentration can preferably be 25 to 1000 ppm.

[0072] It can be understood that when the oil-immersed equipment oil and gas detection device 20 is working, the control unit 205 selects a preset power according to the requirement for the actual power of the narrow-bandwidth laser. For example, if the actual power of the narrow-bandwidth laser is required to be a megawatt, the preset power is selected as a megawatt. At this time, the standard photoacoustic signal intensity generated when the characteristic gas of standard concentration in the standard gas sample absorbs the narrow-bandwidth laser with preset power should be b millivolts, where b is the electrical signal value corresponding to the size of the sound signal generated when the characteristic gas of standard concentration in the standard gas sample absorbs the narrow-bandwidth laser with preset power.

[0073] However, when the power of the narrow bandwidth laser attenuates, the actual power of the narrow bandwidth laser is less than the preset power, resulting in the second photoacoustic signal intensity detected at this time being only c millivolts. At this time, it can be determined that the photoacoustic signal intensity attenuation value caused by the power attenuation of the narrow bandwidth laser at the standard concentration is bc millivolts. The control unit 205 can determine the narrow bandwidth laser power attenuation value as d according to the correspondence between the gas concentration, the narrow bandwidth laser power attenuation value and the photoacoustic signal intensity attenuation value, and thus correct the preset power according to the narrow bandwidth laser power attenuation value, so that the actual power of the narrow bandwidth laser is a megawatts, and the actual photoacoustic signal intensity generated by the characteristic gas in the gas sample to be measured after absorbing the narrow bandwidth laser with a megawatt power can be obtained, thereby obtaining the actual concentration of the characteristic gas in the gas sample to be measured, so that the detection result of the characteristic gas in the gas sample to be measured can be corrected to improve the detection accuracy.

[0074] In one embodiment, the control unit 205 is further configured to send an adjustment enable signal to the measurement unit 204 when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample.

[0075] The measuring unit 204 is further configured to dynamically adjust the preset power according to the adjustment enable signal until the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity.

[0076] The measuring unit 204 is further used to control the photoacoustic spectrometer to re-measure the characteristic gas in the gas sample to be measured using the narrow bandwidth laser with the adjusted preset power to obtain the actual photoacoustic signal intensity of the characteristic gas in the gas sample to be measured.

[0077] The control unit 205 is further configured to determine the actual concentration corresponding to the actual photoacoustic signal intensity according to the corresponding relationship among the gas concentration, the narrow bandwidth laser power and the photoacoustic signal intensity.

[0078] It should be noted that dynamically adjusting the preset power refers to adjusting the preset power within a certain numerical range. During the adjustment process, each preset power obtains a corresponding second photoacoustic signal intensity, and the adjustment is stopped until the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity. At this time, the preset power corresponding to the second photoacoustic signal intensity is the corrected preset power.

[0079] It can be understood that when the oil-immersed equipment oil and gas detection device 20 is working, if the preset power is a megawatt, the standard photoacoustic signal intensity generated when the characteristic gas of standard concentration in the standard gas sample has a narrow bandwidth laser with preset power should be b millivolts, but when the power of the narrow bandwidth laser is attenuated, the actual power of the narrow bandwidth laser is less than the preset power, resulting in the second photoacoustic signal intensity detected at this time being only c millivolts. At this time, the control unit 205 controls the measuring unit 204 to dynamically adjust the preset power until the second photoacoustic signal intensity generated when the characteristic gas of standard concentration in the standard gas sample absorbs the narrow bandwidth laser is b millivolts, and the preset power can be adjusted and corrected, so that the actual photoacoustic signal intensity generated after the characteristic gas in the gas sample to be tested absorbs the narrow bandwidth laser with a power of a megawatt can be obtained, thereby obtaining the actual concentration of the characteristic gas in the gas sample to be tested.

[0080] In one embodiment, the control unit 205 is also used to determine the sample standard concentration of the characteristic gas in the standard gas sample corresponding to the standard photoacoustic signal intensity, the sample measurement concentration of the characteristic gas in the standard gas sample corresponding to the second photoacoustic signal intensity, and the measurement concentration of the characteristic gas in the gas sample to be tested corresponding to the first photoacoustic signal intensity based on the correspondence between the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity.

[0081] The control unit 205 is further configured to determine a concentration measurement error according to the sample standard concentration and the sample measurement concentration when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample.

[0082] The control unit 205 is further configured to correct the measured concentration according to the concentration measurement error to obtain the actual concentration.

[0083] It can be understood that the preset power is a megawatts, and the sample standard concentration of the characteristic gas in the standard gas sample is b. When the power of the narrow-bandwidth laser attenuates, the actual power of the narrow-bandwidth laser is less than the preset power, resulting in the second photoacoustic signal intensity detected at this time being only c millivolts. According to the correspondence between the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity, the sample measured concentration of the characteristic gas in the standard gas sample corresponding to the second photoacoustic signal intensity can be obtained as d, thereby determining the concentration measurement error as bd. At this time, the control unit 205 can correct the measured concentration of the characteristic gas in the gas sample to be measured according to the concentration measurement error to obtain the actual concentration of the characteristic gas in the gas sample to be measured.

[0084] In one embodiment, the control unit 205 is further configured to determine the actual power of the narrow-bandwidth laser corresponding to the second photoacoustic signal intensity according to the corresponding relationship among the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity.

[0085] The control unit 205 is further configured to determine a power attenuation ratio of the laser power according to the actual power and the preset power when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample.

[0086] The control unit 205 is further configured to send a correction enable signal to the measurement unit 204 according to the power attenuation ratio.

[0087] The measuring unit 204 is further configured to modify the preset power according to the modification enable signal.

[0088] The measuring unit 204 is further used to control the photoacoustic spectrometer to re-measure the characteristic gas in the gas sample to be measured using a narrow-bandwidth laser with a corrected preset power to obtain an actual photoacoustic signal intensity of the characteristic gas in the gas sample to be measured.

[0089] The control unit 205 is further configured to determine the actual concentration corresponding to the actual photoacoustic signal intensity according to the corresponding relationship among the gas concentration, the narrow bandwidth laser power and the photoacoustic signal intensity.

[0090] It should be noted that when the oil-immersed equipment oil and gas detection device 20 is working, if the actual power requirement of the narrow bandwidth laser is 20 MW, the preset power is 20 MW, but the actual power of the narrow bandwidth laser is detected to be only 10 MW, and the ratio of the actual power of the narrow bandwidth laser to the preset power is 0.5. At this time, the preset power of the narrow bandwidth laser is corrected, and the preset power of the narrow bandwidth laser is increased so that the corrected preset power is 20 ÷ 0.5 = 40 MW, so that the corrected actual power of the narrow bandwidth laser is 20 MW. At this time, the narrow bandwidth laser with an actual power of 20 MW is used to re-measure the characteristic gas in the gas sample to be measured, and the actual photoacoustic signal intensity generated by the characteristic gas in the gas sample to be measured after absorbing the narrow bandwidth laser with a power of 20 MW can be obtained, thereby obtaining the actual concentration of the characteristic gas in the gas sample to be measured.

[0091] like Figure 3 As shown, Figure 3 This is a second structural schematic diagram of the oil and gas detection device 20 for oil-immersed equipment provided in an embodiment of the present application.

[0092] In one embodiment, the oil-immersed equipment oil and gas detection device 20 further includes an alarm unit 206, and the alarm unit 206 is used to issue an alarm.

[0093] Specifically, the control unit 205 is further configured to determine whether the intensity of the second photoacoustic signal is lower than an alarm threshold.

[0094] If so, the control unit 205 sends a measurement unit fault alarm to the alarm unit 206, and the alarm unit 206 issues an alarm based on the measurement unit fault alarm to promptly remind the staff that an uncorrectable fault has occurred in the measurement result of the measurement unit 204; if not, the control unit 205 determines whether the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity.

[0095] like Figure 4 As shown, Figure 4 The first structural diagram of the measuring unit 204 provided in the embodiment of the present application is as follows. The measuring unit 204 comprises a laser unit 21 , a spectrometer unit 22 , a first gas detection unit 23 and a second gas detection unit 24 .

[0096] Specifically, the control unit 205 is further configured to send a light-emitting enable signal to the laser unit 21 , and send a measurement enable signal to the first gas detection unit 23 and the second gas detection unit 24 .

[0097] It should be noted that when measuring the gas sample to be measured, the gas sample to be measured flows from the degassing unit 202 into the first gas detection unit 23 through the gas path unit 203 , and the standard gas sample is pre-sealed in the second gas detection unit 24 .

[0098] Specifically, the laser unit 21 is used to emit narrow-bandwidth laser light with preset power and preset wavelength according to the light emission enable signal; the laser unit 21 may be a narrow-bandwidth laser, such as a DFB laser.

[0099] Specifically, the light splitting unit 22 is used to split the narrow-bandwidth laser into a first light beam and a second light beam according to a set power ratio.

[0100] It should be noted that the splitting unit 22 can be a coupler, and the splitting unit 22 can split the narrow bandwidth laser into several paths according to a set power ratio. For example, if the power of the narrow bandwidth laser is 20 megawatts and the set power ratio is 1:1, the power of the first beam and the second beam into which the narrow bandwidth laser is split by the splitting unit 22 are both 10 megawatts; the splitting unit 22 can be a coupler.

[0101] It can be understood that the power of the first light beam and the power of the second light beam are both proportional to the power of the narrow-bandwidth laser emitted by the laser unit 21. Therefore, after determining the power of the second light beam by the intensity of the second photoacoustic signal, the actual power of the narrow-bandwidth laser and the power of the first light beam can be obtained by simple proportional conversion.

[0102] In one embodiment, the power ratio is set to 1:1, that is, the power of the first light beam is the same as the power of the second light beam.

[0103] In one embodiment, the light splitting unit 22 has two light outlets, and the narrow-bandwidth laser emitted by the light emitting unit is split by the light splitting unit 22 to form the first light beam and the second light beam, which are emitted through the two light outlets respectively.

[0104] Specifically, the first gas detection unit 23 is used to receive the gas sample to be measured according to the measurement enable signal, and control the photoacoustic spectrometer in the first gas detection unit 23 to use the first light beam to measure the characteristic gas in the gas sample to be measured. The photoacoustic spectrometer in the first gas detection unit 23 is used to detect the first photoacoustic signal generated after the characteristic gas in the gas sample to be measured absorbs the first light beam, and feed back the first photoacoustic signal to the control unit 205.

[0105] Specifically, the second gas detection unit 24 is used to accommodate the standard gas sample, and the second gas detection unit 24 is also used to control the photoacoustic spectrometer in the second gas detection unit 24 to use the second light beam to measure the characteristic gas in the standard gas sample according to the measurement enable signal. The photoacoustic spectrometer in the second gas detection unit 24 is used to detect the characteristic gas in the standard gas sample that absorbs the second light beam to generate a second photoacoustic signal, and feed back the second photoacoustic signal to the control unit 205.

[0106] Specifically, the control unit 205 is further used to determine the first photoacoustic signal intensity of the characteristic gas in the gas sample to be tested and the second photoacoustic signal intensity of the characteristic gas in the standard gas sample according to the received first photoacoustic signal and the second photoacoustic signal.

[0107] Specifically, the first gas detection unit 23 includes a first photoacoustic cell 231 and a first microphone 232 arranged in the first photoacoustic cell 231; the first photoacoustic cell 231 is used to accommodate the gas sample to be tested, and the first microphone 232 is used to detect the first photoacoustic signal generated after the characteristic gas in the gas sample to be tested absorbs the first light beam, and the first microphone 232 can convert the sound signal generated after the characteristic gas in the gas sample to be tested absorbs the first light beam into an analog signal.

[0108] It can be understood that the first photoacoustic cell 231 and the first microphone 232 form a photoacoustic spectroscopy device in the first gas detection unit 23 .

[0109] Among them, the first photoacoustic pool 231 includes a first resonant cavity 231a and a first air inlet 231b and a first air outlet 231c connected to the first resonant cavity 231a; the first resonant cavity 231a is used to accommodate the gas sample to be measured; the first air inlet 231b can be connected to the gas circuit unit 203 through a pipeline, so as to connect the gas sample to be measured in the gas circuit unit 203 to the first resonant cavity 231a; the first air outlet 231c can be connected to the gas circuit unit 203 through a pipeline, so as to flow the gas sample to be measured after the measurement from the first resonant cavity 231a into the gas circuit unit 203. The gas sample to be measured may contain polluted gas that pollutes the environment. The gas sample to be measured after the measurement is processed by the gas circuit unit 203 and then discharged to avoid the gas to be measured from polluting the environment.

[0110] The first photoacoustic cell 231 has a transparent window, and the first light beam passes through the transparent window of the first photoacoustic cell 231 to enter the first resonant cavity 231 a.

[0111] Specifically, the second gas detection unit 24 includes a second photoacoustic cell 241 and a second microphone 242 arranged in the second photoacoustic cell 241; the second photoacoustic cell 241 is used to accommodate the standard gas sample, and the second microphone 242 is used to detect the second photoacoustic signal generated after the characteristic gas in the standard gas sample absorbs the second light beam. The second microphone 242 can convert the sound signal generated after the characteristic gas in the gas sample to be tested absorbs the second light beam into an analog signal.

[0112] It can be understood that the second photoacoustic cell 241 and the second microphone 242 form a photoacoustic spectroscopy device in the second gas detection unit 24 .

[0113] The second photoacoustic cell 241 includes a second resonant cavity 241 a , and the second resonant cavity 241 a is used to accommodate the standard gas sample, and the second resonant cavity 241 a is sealed.

[0114] The photoacoustic cell also has a transparent window, and the second light beam passes through the transparent window of the second photoacoustic cell 241 to enter the second resonant cavity 241 a.

[0115] In one embodiment, the measuring unit 204 also includes a collimating unit 25, which is used to collimate and aggregate the first light beam and the second light beam emitted by the spectroscopic unit 22, and control the first light beam to enter the first gas detection unit 23, and control the second light beam to enter the second gas detection unit 24.

[0116] The collimating unit 25 may include a first collimator 251 for collimating and converging the first light beam and a second collimator 252 for collimating and converging the second light beam.

[0117] In one implementation, the laser unit 21 includes a temperature control unit 211 and a laser assembly 212 .

[0118] Specifically, the laser assembly 212 is used to emit narrow-bandwidth laser.

[0119] Specifically, the temperature control unit 211 is used to receive the light-emitting enable signal sent by the control unit 205, and control the laser assembly 212 to emit narrow-bandwidth lasers corresponding to each temperature control temperature under the control of multiple temperature control temperatures according to the light-emitting enable signal.

[0120] Specifically, the control unit 205 is further used to record the first photoacoustic signal intensity corresponding to each temperature control temperature, and record the temperature control temperature corresponding to the maximum intensity of the first photoacoustic signal as the preset temperature, and the preset temperature corresponds to the preset wavelength.

[0121] Specifically, the control unit 205 is further configured to send a light-emitting enable signal corresponding to the preset temperature to the temperature control unit 211 .

[0122] Specifically, the temperature control unit 212 is further used to control the laser assembly 211 to emit narrow-bandwidth laser with preset power and preset wavelength under the control of the preset temperature according to the light-emitting enable signal corresponding to the preset temperature.

[0123] It should be noted that in the laser unit 21, such as a DFB laser, the temperature control unit 211 can control the temperature of the laser component 212. The laser component 212 includes a Bragg grating and a medium formed by a semiconductor material. By changing the temperature of the medium, the wavelength of the narrow-bandwidth laser emitted by the DFB laser can be changed, so that the DFB laser can emit a narrow-bandwidth laser of a set wavelength by controlling the temperature of the medium, and the temperature control temperature of the medium corresponds one-to-one to the wavelength of the narrow-bandwidth laser emitted by the DFB laser. When the power of the narrow-bandwidth laser and the concentration of the characteristic gas remain unchanged, the closer the wavelength of the narrow-bandwidth laser is to the absorption peak of the characteristic gas, the greater the intensity of the photoacoustic signal generated by the characteristic gas. When the intensity of the first photoacoustic signal is maximum, the temperature control temperature of the laser component 212 is recorded as a preset temperature, and the preset temperature is corresponded to the preset wavelength. At this time, the preset wavelength of the narrow-bandwidth laser is closest to the absorption peak of the characteristic gas in the gas sample to be measured, so that the photoacoustic signal intensity generated when the characteristic gas in the gas sample to be measured absorbs the narrow-bandwidth laser with a preset wavelength can be greater, thereby improving the measurement accuracy.

[0124] See also Figure 5 and Figure 6 , Figure 5 is a schematic diagram of the structure of the temperature control unit 211 provided in an embodiment of the present application, Figure 6 Schematic diagram of a temperature control circuit in a temperature control unit 211 provided in an embodiment of the present application. The temperature control unit 211 is used to control the temperature of a laser assembly 212 .

[0125] In one embodiment, the temperature control unit 211 includes a voltage controller 211a, a voltage regulator 211b, a voltage comparator 211c, a microprogram controller 211d and a thermostat 211f. The voltage controller 211a, the voltage regulator 211b, the voltage comparator 211c and the microprogram controller 211d constitute a temperature control circuit TC of the temperature control unit 211.

[0126] Specifically, the voltage controller 211a is used to provide a reference voltage, which is an optimal value of the effective working voltage of the laser component 212. That is, when the effective working voltage of the laser component 212 is equal to the reference voltage, the laser component 212 can emit a narrow-bandwidth laser with a set frequency and a set power for concentration detection of characteristic gases in the gas sample to be measured, so that the measurement accuracy and sensitivity of the measuring unit 204 are optimized; in addition, the closer the effective working voltage of the laser component 212 is to the reference voltage, the higher the accuracy and sensitivity of the measuring unit 204 in measuring the concentration of the characteristic gas.

[0127] The input end of the voltage regulator 211b is electrically connected to the output end of the voltage controller 211a, and is used to stabilize the reference voltage provided by the voltage controller 211a, eliminate the fluctuation of the reference voltage, and improve the stability and consistency of the reference voltage.

[0128] The first input terminal of the voltage comparator 211c is electrically connected to the output terminal of the voltage regulator 211b, and the second input terminal of the voltage comparator 211c is electrically connected to the output terminal of the voltage acquisition module 211g. The voltage comparator 211c is used to compare the effective working voltage of the laser component 212 with the voltage value of the reference voltage provided by the voltage controller 211a, and transmit the comparison result to the microprogram controller 211d.

[0129] The input end of the microprogram controller 211d is electrically connected to the output end of the voltage comparator 211c, and is used to receive and analyze the comparison result, and send a corresponding temperature adjustment instruction to the thermostat 211f according to the comparison result; specifically, when the comparison result is that the effective working voltage of the laser component 212 is less than the reference voltage, the microprogram controller 211d sends a temperature adjustment instruction to the thermostat 211f to reduce the temperature of the laser component 212; when the comparison result is that the effective working voltage of the laser component 212 is greater than the reference voltage, the microprogram controller 211d sends a temperature adjustment instruction to the thermostat 211f to increase the temperature of the laser component 212; when the comparison result is that the effective working voltage of the laser component 212 is equal to the reference voltage, the microprogram controller 211d sends a temperature adjustment instruction to the thermostat 211f to maintain the temperature of the laser component 212. The input end of the thermostat 211f is electrically connected to the output end of the microprogram controller 211d, and is used to adjust the temperature of the laser assembly 212 under the control of the temperature adjustment instruction so that the laser assembly 212 works within a preset temperature range.

[0130] In one embodiment, if Figure 7 , Figure 7This is a second structural diagram of the measurement unit 204 provided in an embodiment of the present application, wherein the measurement unit 204 includes a plurality of gas detection units 26 that do not interfere with each other.

[0131] Specifically, the gas circuit unit 203 is used to control the gas sample to be measured to flow from the gas circuit unit 203 into all the gas detection units 26 according to the measurement enable signal.

[0132] The gas detection unit 26 is used to measure the concentration of the characteristic gas using a narrow bandwidth laser corresponding to the characteristic gas to be detected by the gas detection unit 26 according to the measurement enable signal.

[0133] It should be noted that the characteristic gas to be measured by the gas detection unit 26 refers to the characteristic gas that the gas detection unit 26 needs to measure; the gas detection unit 26 controls the photoacoustic spectrometer in the gas detection unit 26 according to the measurement enable signal to use a narrow bandwidth laser corresponding to the characteristic gas to be measured by the gas detection unit 26.

[0134] It should be noted that each of the gas detection units 26 can independently realize the measurement of a characteristic gas. The gas sample to be measured is flushed into multiple gas detection units 26. The characteristic gas in the gas sample to be measured can be measured simultaneously by using multiple gas detection units 26 that do not interfere with each other. Different types of characteristic gases correspond to narrow-bandwidth lasers of different wavelengths. Different gas detection units 26 can use narrow-bandwidth lasers of different wavelengths to measure different types of characteristic gases in the gas sample to be measured, thereby simultaneously measuring the concentrations of multiple characteristic gases in the gas sample to be measured.

[0135] In one embodiment, multiple gas detection units 26 are connected in series, which can also be understood as multiple gas detection units 26 are connected in cascade; the gas circuit unit 203 is used to control the gas sample to be tested to flow from the gas circuit unit 203 into all the gas detection units 26 in sequence according to the measurement enable signal.

[0136] The two adjacent gas detection units 26 are connected via a connecting pipe 271 , and a valve is provided on the connecting pipe 271 , so that the gas samples to be tested can flow into the gas detection units 26 in sequence, while ensuring that all gas detection units 26 do not interfere with each other.

[0137] It should be noted that each of the gas detection units 26 is provided with an air inlet 261 and an air outlet 262. When the measuring unit 204 includes m gas detection units 26, the m gas detection units 26 are connected in cascade. The air inlet 261 of the gas detection unit 26 at the first stage can also be connected to the gas circuit unit 203 through a connecting pipe 271 provided with a valve, so as to be connected to the gas sample to be measured flowing out of the gas circuit unit 203; after the gas sample to be measured flows into the gas detection unit 26 of the first stage, the gas sample to be measured flows into all the gas detection units 26 in turn through the connecting pipe 271; the air outlet 262 of the gas detection unit 26 at the last stage can also be connected to the gas circuit unit 203 through a connecting pipe 271 provided with a valve, so as to flow the gas sample to be measured after the measurement from the gas detection unit 26 into the gas circuit unit 203, and the gas sample to be measured after the measurement is processed by the gas circuit unit 203 is discharged to avoid the gas to be measured from polluting the environment.

[0138] The gas inlet 261 and the gas outlet 262 may be located at the same side of the gas detection unit 26 , so that two adjacent gas detection units 26 can be connected via the connecting pipe 271 .

[0139] like Figure 8 , Figure 8 This is a third structural diagram of the measurement unit 204 provided in an embodiment of the present application.

[0140] In one embodiment, the measurement unit 204 further includes a box 272 , and all the gas detection units 26 are disposed in the box 272 .

[0141] In one embodiment, the box body 272 can be a square structure, and a plurality of slide rails 273 for supporting the gas detection unit 26 are arranged on the inner wall of the box body 272. The plurality of slide rails 273 are arranged at intervals along the height direction of the box body 272, and the gas detection unit 26 corresponds to the slide rails 273 one by one; the gas detection unit 26 is slidably connected to the slide rails 273 along the length direction of the slide rails 273 to facilitate the inspection and replacement of the gas detection unit 26. For example, when a gas detection unit 26 fails, the staff can pull the gas detection unit 26 out of the box body 272 for inspection. When the gas detection unit 26 cannot be repaired, a gas detection unit 26 with normal function can be used to replace the faulty gas detection unit 26 to avoid the measurement unit 204 from failing to work when a single gas detection unit 26 fails.

[0142] In one embodiment, the box body 272 is further provided with an interface 274, at least one of the interfaces 274 is connected to the control unit 205, and the gas detection unit 26 is provided with a connector 275 matching the interface 274, and the connector 275 is inserted into the interface 274. An information interaction bridge is built by connecting the interface 274 and the connector 275 to realize information interaction between the control unit 205 and the gas detection unit 26, thereby realizing the control of the gas detection unit 26 by the control unit 205 and the information feedback of the gas detection unit 26 to the control unit 205.

[0143] In one embodiment, each gas detection unit 26 includes an independent laser, which is used to emit narrow-bandwidth laser according to the light-emitting enable signal sent by the control unit 205. The laser can be a narrow-bandwidth laser, such as a DFB laser.

[0144] Among them, all gas detection units 26 can be used to simultaneously use corresponding lasers to output narrow-bandwidth lasers corresponding to each characteristic gas to measure the concentration of the corresponding characteristic gas, so as to improve the detection efficiency.

[0145] In one embodiment, see Figures 9 to 13 The measuring unit 204 further includes a signal processing circuit, which includes a photoelectric conversion circuit 281, a first signal amplification circuit 282, a bandpass filtering circuit 283, a second signal amplification circuit 284 and an A / D conversion circuit 285.

[0146] like Fig. 9 , Fig. 9 The schematic circuit diagram of the photoelectric conversion circuit of the oil-gas detection device for oil-immersed equipment provided in the embodiment of the present application; the photoelectric conversion circuit 281 is used to convert the optical signal into an electrical signal, and the electrical signal at this time is an analog signal. The photoelectric conversion circuit 281 includes an integrated circuit LTC6268. The integrated circuit LTC6268 and various circuit elements convert the phase change of the optical signal into the phase change before and after the analog signal, and then after subsequent processing by the circuit unit, the phase change before and after the analog signal is finally converted into the concentration of the characteristic gas.

[0147] Fig.10 The circuit schematic diagram of the first signal amplifying circuit of the oil and gas detection device for oil-immersed equipment provided in the embodiment of the present application; the first signal amplifying circuit 282 is connected to the output end of the photoelectric conversion circuit 281, and is used to amplify the analog quantity of the optical signal. Since the analog quantity of the optical signal is relatively weak, it is more convenient to further process the optical signal after amplification. The amplifier of the first signal amplifying circuit 282 adopts AD8629.

[0148] Fig.11A circuit schematic diagram of a bandpass filter circuit for an oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application; the input end of the bandpass filter circuit 283 is connected to the output end of the first signal amplification circuit 282, and the bandpass filter circuit 283 is used to filter the signal output by the first signal amplification circuit 282, and its purpose is to filter out useless high-frequency and low-frequency signals and extract useful intermediate-frequency signals. The bandpass filter circuit 283 uses an integrated circuit LT1067.

[0149] Fig.12 A circuit schematic diagram of the second signal amplifying circuit of the oil-gas detection device for oil-immersed equipment provided in an embodiment of the present application; the input end of the second signal amplifying circuit 284 is connected to the output end of the bandpass filtering circuit 283, and the output signal of the bandpass filtering circuit 283 is amplified and transmitted to the A / D conversion circuit 285, which is equivalent to a secondary amplification of the signal. The purpose is to make the signal obtained by the A / D conversion circuit 285 more accurate and easier to convert. The second signal amplifying circuit 284 also uses the integrated circuit LT1067.

[0150] Fig.13 The circuit schematic diagram of the A / D conversion circuit of the oil-gas detection device for oil-immersed equipment provided in the embodiment of the present application; the input end of the A / D conversion circuit 285 is connected to the output end of the second signal amplification circuit 284, and is used to convert the analog quantity output by the second signal amplification circuit 284 into a digital quantity, which is a process of converting a discrete quantity into a continuous quantity, so that the A / D conversion circuit 285 uses the integrated circuit AD7980.

[0151] like Fig.14 As shown, Fig.14 This is a third structural schematic diagram of the oil and gas detection device 20 for oil-immersed equipment provided in an embodiment of the present application.

[0152] In one embodiment, the process of separating oil and gas from a cooling oil sample by headspace degassing includes four stages.

[0153] In the first stage, this stage mainly pumps the pressure in the oil tank 201a to the first target pressure, so that a negative pressure is formed between the oil-immersed device 10 and the oil tank 201a, so that the cooling oil sample in the oil-immersed device 10 enters the oil tank 201a. First, the control unit 205 controls the driving piston 2021b of the first driving motor 2021a in the suction device 2021 in the degassing unit 202 to perform suction, so as to pump the gas in the oil tank 201a into the cylinder 2021c in the suction device 2021, and discharge the gas in the cylinder 2021c through X of the gas circuit unit 203, so that a negative pressure is formed in the oil tank 201a.

[0154] The gas circuit unit 203 includes a first gas valve 2031, a second gas valve 2032, a third gas valve 2033 and a fourth gas valve 2034. For example, the first port 2031a and the second port 2031b of the first gas valve 2031 are connected, and the gas extraction device 2021 extracts part of the gas in the oil tank 201a into the cylinder 2021c, and then the first port 2031a and the third port 2031c of the first gas valve 2031 are connected, and the gas in the cylinder 2021c is discharged through the third gas valve 2033. Repeat the above steps to reduce the pressure in the oil tank 201a to the first target pressure. For example, the external atmospheric pressure is the standard atmospheric pressure of 100Kpa, and the first target pressure in the oil tank 201a can be 2Kpa. The pressure in the oil tank 201a can be directly obtained by the pressure sensor 201d.

[0155] In the second stage, the pressure difference between the oil tank 201a and the oil-immersed device 10 causes the cooling oil sample in the oil-immersed device 10 to enter the oil tank 201a. First, the control unit 205 controls the first valve 2035 to open so that the oil-immersed device 10 and the oil tank 201a are connected. Due to the pressure difference between the oil-immersed device 10 and the oil tank 201a, the cooling oil sample in the oil-immersed device 10 enters the oil tank 201a; when the cooling oil sample in the oil tank 201a reaches the height measured by the upper liquid level sensor 201b, the control unit 205 controls the first valve 2035 to close. The height of the upper liquid level sensor 201b can be set according to the height of the oil tank 201a. For example, the height of the upper liquid level sensor 201b can be 75% of the height of the oil tank 201a. Alternatively, the height of the upper liquid level sensor 201b can be set according to the stirring speed of the stirring member 2022 in the oil tank 201a. For example, when the stirring speed of the stirring member 2022 is 2400 rpm, the height of the upper liquid level sensor 201b can be 75% of the height of the oil tank 201a. When the stirring speed of the stirring member 2022 is 3000 rpm, the height of the upper liquid level sensor 201b can be 60%. The height of the upper liquid level sensor 201b can be 70% of the height of the oil tank 201a to avoid the liquid level exceeding the critical height of the oil tank 201a when the cooling oil sample is stirred due to the excessive rotation speed of the stirring member 2022; alternatively, the height of the upper liquid level sensor 201b can be set according to the stirring temperature of the cooling oil sample in the oil tank 201a. For example, when the stirring temperature of the cooling oil sample is 50°C, the height of the upper liquid level sensor 201b can be 75% of the height of the oil tank 201a; when the stirring temperature of the cooling oil sample is 70°C, the height of the upper liquid level sensor 201b can be 70% of the height of the oil tank 201a.

[0156] In the third stage, the gas to be tested in the cooling oil sample enters the measuring unit 204 through the air extraction device 2021 and the gas circuit unit 203. First, the control unit 205 controls the first port 2031a and the second port 2031b of the first gas valve 2031 to communicate with each other, so that the air extraction device 2021 is connected to the oil tank 201a, and then the control unit 205 controls the stirring member 2022 to stir the cooling oil sample in the oil tank 201a, and then the air extraction device 2021 extracts the gas to be tested in the cooling oil sample into the cylinder 2021c in the air extraction device 2021, and then the control unit 205 controls the first gas valve 2031 to communicate with the first port 2031a and the second port 2031b of the first gas valve 2031. The first port 2031a and the second port 2031b of the first gas valve 2031 are disconnected, and the first port 2031a and the third port 2031c of the first gas valve 2031 are connected, the second gas valve 2032 and the fourth gas valve 2034 are opened, and the third gas valve 2033 is closed, so that the gas sample to be measured enters the measuring unit 204 through the gas circuit unit 203; secondly, the above steps are repeated until the pressure in the oil tank 201a reaches the second target pressure, the above gas extraction step is stopped, and the first gas valve 2031 is in a closed state. The second target pressure can be equal to or different from the first target pressure, and the specific value of the second target pressure can be limited according to actual conditions.

[0157] In the fourth stage, the cooling oil sample in the oil tank 201a flows back into the oil-immersed device 10. First, the control unit 205 controls the second valve 2036 to open, so that the oil-immersed device 10 is connected to the oil tank 201a, and then controls the oil pump to pump the cooling oil sample in the oil tank 201a into the oil-immersed device 10. When the liquid level of the cooling oil sample in the oil tank 201a reaches the height measured by the lower liquid level sensor 201c in the oil tank 201a, the control unit 205 controls the oil pump to stop working and close the second valve 2036. The height measured by the lower liquid level sensor 201c can be the bottom of the oil tank 201a, and the specific position is not limited in detail in this application.

[0158] According to the working process of the oil-gas detection device 20 for oil-immersed equipment, since the gas to be tested in the oil tank 201a needs to be degassed within the target degassing time, the stirring speed of the stirring member 2022 directly affects the degassing rate of the gas to be tested. For sample oils of different viscosities or temperatures, and at different stirring speeds, the degassing rate of the gas to be tested in the sample oil from the oil-gas separation device in the oil-immersed equipment oil-gas detection device 20 is different. However, the existing oil-immersed equipment oil-gas detection device 20 is usually unable to accurately set the stirring speed of the stirring member 2022 in the oil-gas separation device, resulting in a technical problem that the gas to be tested in the sample oil cannot be separated from the oil-gas separation device within the target time. This embodiment mainly determines the first stirring speed of the stirring member 2022 by the predicted concentration of the gas to be tested in the cooling oil sample.

[0159] In one embodiment, due to the influence of various uncertain factors, the concentration value of the characteristic gas actually obtained by the measuring unit 204 is generally greater than the initial predicted concentration of this embodiment. Since the cooling oil samples belong to the same batch of cooling oil samples, the stirring speed of the stirring component 2022 of the next cycle can be adjusted according to the difference between the concentration value of the characteristic gas in the current cycle and the predicted concentration. This step may include: obtaining a first difference between the concentration of the characteristic gas in the current measurement cycle and the predicted concentration of the gas to be measured in the cooling oil sample; judging whether the first difference is greater than a first threshold; if the first difference is greater than the first threshold, according to the correlation between the concentration, degassing time and stirring speed, based on the first difference and the target degassing time, determining the second stirring speed of the stirring component 2022 in the next measurement cycle; if the first difference is less than the first threshold, the first stirring speed of the stirring component 2022 is the target stirring speed of the stirring component 2022 in the current measurement cycle.

[0160] In one embodiment, when a first difference between the concentration of the characteristic gas in the current measurement cycle and the predicted concentration of the gas to be measured in the cooling oil sample is greater than a first threshold value, the stirring speed needs to be adjusted, and the stirring speed of the stirring member 2022 has an upper limit, i.e., a critical stirring speed. If the difference between the concentration of the characteristic gas in the previous measurement cycle and the predicted concentration of the gas to be measured in the cooling oil sample is large, the stirring speed of the stirring member 2022 needs to be increased to a second stirring speed exceeding the critical stirring speed, and then other adjustment factors need to be adjusted to compensate for the limitation of the stirring speed.

[0161] Specifically, this embodiment uses the correlation between temperature and stirring speed to adjust the stirring temperature of the stirring member 2022, that is, the temperature of the cooling oil sample, to compensate for the limitation of the stirring speed when the stirring speed cannot be increased. This step may include: determining whether the second stirring speed is greater than the critical stirring speed of the stirring member 2022; if the second stirring speed is greater than the critical stirring speed of the stirring member 2022, the critical stirring speed is the target stirring speed of the stirring member 2022 for the next measurement cycle; according to the correlation between temperature, concentration and stirring speed, based on the critical stirring speed and the concentration of the characteristic gas, the initial temperature of the cooling oil sample in the next measurement cycle is determined; if the second stirring speed is less than the critical stirring speed of the stirring member 2022, the second stirring speed is the target stirring speed of the stirring member 2022 for the next measurement cycle.

[0162] In one embodiment, when a first difference between the concentration of the characteristic gas in the current measurement cycle and the predicted concentration of the gas to be measured in the cooling oil sample is greater than a first threshold, the stirring speed needs to be adjusted; and after the stirring speed of the stirring member 2022 is increased, the liquid level of the cooling oil sample in the corresponding oil tank 201a will increase. Since the oil tank 201a is connected to the corresponding oil and gas pipeline, the increase in the liquid level of the cooling oil sample may cause the cooling oil sample to enter other devices through the oil and gas pipeline. Therefore, the cooling oil sample in the oil tank 201a has a critical liquid level to prevent the cooling oil sample from entering other components. Therefore, this step may include: obtaining the cooling oil sample in the current measurement cycle The liquid level of the cooling oil sample; determine whether the liquid level of the cooling oil sample is greater than the critical liquid level of the cooling oil sample; if the liquid level of the cooling oil sample is greater than the critical liquid level of the cooling oil sample, the critical liquid level is the liquid level of the cooling oil sample in the next measurement cycle, and according to the correlation between the liquid level, concentration and stirring speed, based on the critical liquid level and the concentration of the characteristic gas, determine the stirring speed of the stirring component 2022 in the next measurement cycle; if the liquid level of the cooling oil sample is less than the critical liquid level of the cooling oil sample, the second stirring speed is the target stirring speed of the stirring component 2022 in the next measurement cycle.

[0163] In one embodiment, the degassing time of the current measurement cycle is also an important reference value for setting the stirring speed. The degassing time represents the degassing rate of the gas to be measured in the cooling oil sample. If the degassing time is short, the degassing rate of the gas to be measured is large, corresponding to a larger stirring speed, and the stirring speed of the next measurement cycle needs to be reduced to make the degassing time of the gas to be measured equal to the target degassing time; if the degassing time is long, the degassing rate of the gas to be measured is small, corresponding to a smaller stirring speed, and the stirring speed of the next measurement cycle needs to be increased to make the degassing time of the gas to be measured equal to the target degassing time. Therefore, this step may include: obtaining the degassing time of the gas to be measured in the cooling oil sample in the current measurement cycle; judging whether the degassing time in the current measurement cycle is equal to the target degassing time; if the degassing time in the current measurement cycle is not equal to the target degassing time, according to the correlation between the concentration, degassing time and stirring speed, based on the concentration of the characteristic gas in the current measurement cycle and the target degassing time, determine the stirring speed of the stirring member 2022 in the next measurement cycle.

[0164] In one embodiment, the suction pressure and suction speed of the suction device 2021 in the oil tank 201a can also be used as variables for adjusting the degassing speed, which will not be described in detail in this application.

[0165] In this step, the concentration of the characteristic gas in the gas sample to be measured obtained by the measuring unit 204 is compared with the predicted concentration of the gas to be measured, and the stirring speed or / temperature of the next measurement cycle is adjusted according to the difference between the two, so that the gas to be measured in the cooling oil sample in the next measurement cycle is separated from the degassing unit 202 within the target degassing time.

[0166] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0167] This document uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An oil-gas detection device for oil-immersed equipment, characterized in that: It includes a control unit, an oil circuit unit, a degassing unit, a gas circuit unit and a measuring unit, wherein: The control unit is used to send a sampling enable signal, a degassing enable signal, and a measurement enable signal; The oil circuit unit is used to receive the sampling enable signal and the degassing enable signal, and the oil circuit unit is also used to obtain a cooling oil sample from the oil-immersed device according to the sampling enable signal, and control the cooling oil sample to flow into the degassing unit according to the degassing enable signal; The degassing unit is used to receive the degassing enable signal and the measurement enable signal, and the degassing unit is also used to degas the cooling oil sample according to the degassing enable signal to obtain the gas sample to be tested, and control the gas sample to be tested to flow into the gas circuit unit according to the measurement enable signal; The gas circuit unit is used to receive the measurement enable signal and control the gas sample to be measured to flow from the gas circuit unit into the measurement unit according to the measurement enable signal; The measuring unit is used to receive the measurement enable signal, and the measuring unit is also used to control the photoacoustic spectrometer in the measuring unit to use a narrow bandwidth laser with a preset power and a preset wavelength to respectively measure a first photoacoustic signal of a characteristic gas in the gas sample to be measured and a second photoacoustic signal of a characteristic gas in a standard gas sample according to the measurement enable signal, and feed back the first photoacoustic signal and the second photoacoustic signal to the control unit; The control unit is further used to determine a first photoacoustic signal intensity of a characteristic gas in the gas sample to be measured and a second photoacoustic signal intensity of a characteristic gas in a standard gas sample according to the first photoacoustic signal and the second photoacoustic signal, and to obtain an actual concentration of the characteristic gas in the gas sample to be measured according to the second photoacoustic signal intensity, the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample, and the first photoacoustic signal intensity; The control unit is also used to determine the operating fault type of the oil-immersed device according to the actual concentration; Wherein, when obtaining the actual concentration of the characteristic gas in the gas sample to be tested, the control unit is also used to determine whether the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity; if they are the same, the control unit determines the measured concentration of the characteristic gas in the gas sample to be tested corresponding to the first photoacoustic signal intensity based on the correspondence between the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity, and the measured concentration is the same as the actual concentration.

2. The oil-gas detection device for oil-immersed equipment according to claim 1, characterized in that: in: The control unit is further configured to determine, when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample, a photoacoustic signal intensity attenuation value caused by the power attenuation of the narrow-bandwidth laser at the standard concentration of the sample according to the second photoacoustic signal intensity and the standard photoacoustic signal intensity; The control unit is also used to determine the narrow bandwidth laser power attenuation value according to the corresponding relationship between the gas concentration, the narrow bandwidth laser power attenuation value and the photoacoustic signal intensity attenuation value; The control unit is further used to send a correction enable signal to the measurement unit according to the narrow bandwidth laser power attenuation value; The measuring unit is further used to correct the preset power according to the correction enable signal; The measuring unit is also used to control the photoacoustic spectrometer to re-measure the characteristic gas in the gas sample to be measured using a narrow-bandwidth laser with a corrected preset power, so as to obtain an actual photoacoustic signal intensity of the characteristic gas in the gas sample to be measured; The control unit is further used to determine the actual concentration corresponding to the actual photoacoustic signal intensity according to the corresponding relationship between the gas concentration, the narrow bandwidth laser power and the photoacoustic signal intensity.

3. The oil-gas detection device for oil-immersed equipment according to claim 1, characterized in that: in: The control unit is further configured to send an adjustment enable signal to the measurement unit when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample; The measuring unit is further used to dynamically adjust the preset power according to the adjustment enable signal until the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity; The measuring unit is also used to control the photoacoustic spectrometer to re-measure the characteristic gas in the gas sample to be measured using the narrow-bandwidth laser with the adjusted preset power to obtain the actual photoacoustic signal intensity of the characteristic gas in the gas sample to be measured; The control unit is further used to determine the actual concentration corresponding to the actual photoacoustic signal intensity according to the corresponding relationship between the gas concentration, the narrow bandwidth laser power and the photoacoustic signal intensity.

4. The oil-gas detection device for oil-immersed equipment according to claim 1, characterized in that: in: The control unit is further used to determine, according to the correspondence between the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity, the sample standard concentration of the characteristic gas in the standard gas sample corresponding to the standard photoacoustic signal intensity, the sample measurement concentration of the characteristic gas in the standard gas sample corresponding to the second photoacoustic signal intensity, and the measurement concentration of the characteristic gas in the gas sample to be measured corresponding to the first photoacoustic signal intensity; The control unit is further configured to determine a concentration measurement error according to the sample standard concentration and the sample measurement concentration when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample; The control unit is further used to correct the measured concentration according to the concentration measurement error to obtain the actual concentration.

5. The oil-gas detection device for oil-immersed equipment according to claim 1, characterized in that: in: The control unit is further used to determine the actual power of the narrow-bandwidth laser corresponding to the second photoacoustic signal intensity according to the corresponding relationship between the gas concentration, the narrow-bandwidth laser power and the photoacoustic signal intensity; The control unit is further configured to determine a power attenuation ratio of the laser power according to the actual power and the preset power when it is determined that the second photoacoustic signal intensity is different from the standard photoacoustic signal intensity of the characteristic gas in the standard gas sample; The control unit is further configured to send a correction enable signal to the measurement unit according to the power attenuation ratio; The measuring unit is further used to correct the preset power according to the correction enable signal; The measuring unit is also used to control the photoacoustic spectrometer to re-measure the characteristic gas in the gas sample to be measured using a narrow-bandwidth laser with a corrected preset power, so as to obtain an actual photoacoustic signal intensity of the characteristic gas in the gas sample to be measured; The control unit is further used to determine the actual concentration corresponding to the actual photoacoustic signal intensity according to the corresponding relationship between the gas concentration, the narrow bandwidth laser power and the photoacoustic signal intensity.

6. The oil-gas detection device for oil-immersed equipment according to claim 1, characterized in that: The measuring unit comprises a laser unit, a spectroscopic unit, a first gas detection unit and a second gas detection unit, wherein: The control unit is further used to send a light-emitting enable signal to the laser unit, and send a measurement enable signal to the first gas detection unit and the second gas detection unit; The laser unit is used to emit narrow-bandwidth laser light with preset power and preset wavelength according to the light emission enable signal; The light splitting unit is used to split the narrow-bandwidth laser into a first light beam and a second light beam according to a set power ratio; The first gas detection unit is used to receive the gas sample to be measured according to the measurement enable signal, and control the photoacoustic spectrometer in the first gas detection unit to use the first light beam to measure the characteristic gas in the gas sample to be measured, the photoacoustic spectrometer in the first gas detection unit is used to detect a first photoacoustic signal generated after the characteristic gas in the gas sample to be measured absorbs the first light beam, and feed back the first photoacoustic signal to the control unit; The second gas detection unit is used to accommodate the standard gas sample, and the second gas detection unit is also used to control the photoacoustic spectrometer in the second gas detection unit to use the second light beam to measure the characteristic gas in the standard gas sample according to the measurement enable signal, and the photoacoustic spectrometer in the second gas detection unit is used to detect the characteristic gas in the standard gas sample to generate a second photoacoustic signal after absorbing the second light beam, and feed back the second photoacoustic signal to the control unit; The control unit is also used to determine the first photoacoustic signal intensity of the characteristic gas in the gas sample to be tested and the second photoacoustic signal intensity of the characteristic gas in the standard gas sample according to the received first photoacoustic signal and the second photoacoustic signal.

7. The oil-gas detection device for oil-immersed equipment according to claim 6, characterized in that: The measuring unit further comprises a collimating unit, wherein: The collimating unit is used to collimate and aggregate the first light beam and the second light beam emitted by the spectroscopic unit, and control the first light beam to be incident on the first gas detection unit, and control the second light beam to be incident on the second gas detection unit.

8. The oil-gas detection device for oil-immersed equipment according to claim 6, characterized in that: The laser unit comprises a laser assembly and a temperature control unit, wherein: The laser assembly is used to emit narrow bandwidth laser; The temperature control unit is used to receive the light-emitting enable signal sent by the control unit, and control the laser assembly to emit narrow-bandwidth lasers corresponding to each temperature control temperature under the control of multiple temperature control temperatures according to the light-emitting enable signal; The control unit is further used to record the first photoacoustic signal intensity corresponding to each temperature control temperature, and record the temperature control temperature corresponding to the maximum intensity of the first photoacoustic signal as the preset temperature, wherein the preset temperature corresponds to the preset wavelength; The temperature control unit is further used to control the laser assembly to emit narrow-bandwidth laser with preset power and preset wavelength under the control of the preset temperature according to a light-emitting enable signal corresponding to the preset temperature.

9. The oil-gas detection device for oil-immersed equipment according to any one of claims 1 to 8, characterized in that: in: The control unit is also used to determine the measured concentration of the characteristic gas in the gas sample to be measured corresponding to the first photoacoustic signal intensity based on the correspondence between the gas concentration, narrow-bandwidth laser power and the photoacoustic signal intensity when it is determined that the second photoacoustic signal intensity is the same as the standard photoacoustic signal intensity, so as to obtain the actual concentration.

10. The oil-gas detection device for oil-immersed equipment according to claim 9, characterized in that: The oil-immersed equipment oil and gas detection device further includes an alarm unit, wherein: The control unit is further used to determine whether the intensity of the second photoacoustic signal is lower than an alarm threshold; If yes, the control unit sends a measurement unit failure alarm to the alarm unit; If not, the control unit determines whether the second photoacoustic signal strength is the same as the standard photoacoustic signal strength.

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