Method and device for detecting characteristic decomposition product NF3 of mixed gas in electrical equipment

Abstract

The invention discloses a method and device for detecting a characteristic decomposition product NF3 of mixed gas in electrical equipment, and the device comprises a preprocessing unit, a gas chamber, a non-dispersive infrared light source assembly, a narrow-band filter, a light path assembly, an infrared detector and a data processing unit. The real-time detection of the NF3 gas on the working site is realized, and the concentration of the NF3 gas can be accurately detected.

Description

Technical Field

[0001] The present invention relates to the technical field of SF6 / N2 mixed gas electrical equipment fault detection, and in particular to a method and device for detecting NF3, a characteristic decomposition product of the mixed gas in electrical equipment. Background Art

[0002] Pure SF6 has superior arc extinguishing and insulation capabilities and is widely used in power equipment. With the development of domestic and international economies and technologies, electricity consumption is increasing, and electrical equipment is becoming more advanced and safer, leading to a continuous increase in the use of SF6 gas.

[0003] In recent years, the shortcomings of SF6, especially the greenhouse effect, have become so prominent that they can no longer be ignored. Reducing the use of SF6 gas in electrical equipment has become a pressing issue. In recent years, the use of SF6 mixtures as insulating gases within equipment to reduce SF6 usage has gained widespread recognition and promotion both domestically and internationally. Researchers have discovered that N2, with its stable chemical properties, low price, and environmental friendliness, can be used to partially replace SF6 in electrical equipment. Therefore, SF6 / N2 mixed gas has enormous industrial potential for high-voltage equipment. The inventors discovered that NF3 gas is produced when defects and failures occur in SF6 / N2 mixed gas electrical equipment during operation. The inventors therefore considered that NF3 gas could be used as a reference for the operational status of SF6 / N2 mixed gas electrical equipment, using SF6 / N2 mixed gas as the insulating gas. This is described in detail below.

[0004] However, the main technologies currently used to detect NF3 gas include catalytic pyrolysis / electrochemical gas sensors, ultra-high temperature pyrolysis / electrochemical gas sensors, and gas chromatographs. However, each technology has certain limitations. Catalytic pyrolysis / electrochemical gas sensors have low detection accuracy and are therefore not an ideal detection method. Although gas chromatographs have high-precision gas analysis capabilities in the laboratory, they are not portable and have complex debugging procedures. Some domestic electrochemical sensor manufacturers have launched sensors specifically for detecting NF3, claiming that they do not require pyrolysis, but the actual test results are not ideal. In addition, the work site is outdoors, and how to carry the detection equipment is also a problem that technicians in this field should consider.

[0005] Therefore, how to detect NF3 gas more simply and accurately has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] The embodiments of the present application provide a method and device for detecting NF3, a characteristic decomposition product of mixed gases in electrical equipment. The device includes a pretreatment unit, a gas chamber, a non-dispersive infrared light source assembly, a narrowband filter, an optical path assembly, an infrared detector, and a data processing unit. The device is not only compact and easy to carry, enabling real-time detection of NF3 gas at the work site, but also can accurately detect the concentration of NF3 gas.

[0007] In a first aspect, the present invention provides a device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, comprising a preprocessing unit, a gas chamber, a non-dispersive infrared light source assembly, a narrowband filter, an optical path assembly, an infrared detector, and a data processing unit, wherein the preprocessing unit is connected to the gas chamber; the non-dispersive infrared light source assembly is connected to the optical path assembly via the narrowband filter; and the infrared detector is connected to the data processing unit; The pre-treatment unit is used to remove impurities from the gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect to obtain a treated mixed gas, and to transport the treated mixed gas to the gas chamber; The non-dispersive infrared light source assembly is used to emit infrared light, so that the infrared light passes through the narrowband filter to obtain infrared light in a preset frequency range, and the infrared light in the preset frequency range passes through the optical path assembly into the air chamber, and the preset frequency range is 980~1060cm -1 ; The infrared detector is used to detect the intensity of the residual light after the processed mixed gas in the gas chamber absorbs the infrared light in the preset wavelength range; The data processing unit is used to convert the intensity of the residual light into the concentration of the characteristic decomposition product NF3 under the partial discharge defect.

[0008] In some embodiments, the device also includes a first temperature sensor and a first temperature controller; the data processing unit is also used to obtain the first temperature in the air chamber detected by the first temperature sensor; when the first temperature is not within a first preset temperature range, the first temperature controller is used to control the first temperature adjustment device to adjust the first temperature in the air chamber to within the first preset temperature range.

[0009] In some embodiments, the device further includes an exhaust gas treatment device; the exhaust gas treatment device is used to perform exhaust gas treatment on the gas in the gas chamber.

[0010] In some embodiments, the exhaust gas treatment device includes an SF6 membrane separation technology unit, a catalytic device, an adsorption device, an alkaline solution washing device and a condensation adsorption device connected in sequence; The SF6 membrane separation technology unit is used to perform membrane separation technology on the gas in the gas chamber to obtain SF6 gas and other gases; The catalytic device is used to perform catalytic oxidation treatment on the other gas to obtain catalytically oxidized gas; The adsorption device is used to perform adsorption treatment on the gas after catalytic oxidation to obtain adsorbed gas; The alkaline solution washing device is used to perform alkaline solution washing on the gas after the adsorption to obtain alkaline solution washed gas; The condensation adsorption device is used to condense and adsorb the gas after washing with the alkali solution to obtain the final gas.

[0011] In some embodiments, the exhaust gas treatment device further includes an exhaust gas detection device; the exhaust gas detection device is connected to the condensation adsorption device, and the exhaust gas detection device is connected to the data processing unit; the exhaust gas detection device is used to detect the final gas and obtain a detection result; The data processing unit is further configured to determine whether the detection result meets the standard; if the detection result meets the standard, the final gas is discharged; if the detection result does not meet the standard, the final gas is further processed.

[0012] In some embodiments, the tail gas treatment device further comprises a compression condensing device and an SF6 collection device connected in sequence, and the compression condensing device is connected to the SF6 membrane separation technology unit; The compression condensation device is used to compress and condense the SF6 gas; The SF6 collecting device is used to collect the compressed and condensed SF6 gas.

[0013] In some embodiments, the device also includes a second temperature sensor and a second temperature controller; the data processing unit is also used to obtain the second temperature around the infrared detector detected by the second temperature sensor; when the second temperature is not within the second preset temperature range, the second temperature controller is used to control the second temperature adjustment device to adjust the second temperature around the infrared detector to the second preset temperature range.

[0014] In some embodiments, the device further includes a constant temperature chamber; the gas chamber and the infrared detector are located in the constant temperature chamber.

[0015] In a second aspect, embodiments of the present application provide a method for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, and a device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, comprising: Using a pretreatment unit to remove impurities from gas decomposition products of the SF6 / N2 mixed gas under partial discharge defects to obtain a treated mixed gas, and transporting the treated mixed gas to a gas chamber; The infrared light is emitted by a non-dispersive infrared light source assembly, so that the infrared light passes through the narrowband filter to obtain infrared light in a preset frequency range. The infrared light in the preset frequency range passes through the optical path assembly and enters the air chamber. The preset frequency range is 980~1060cm -1 ; detecting, using an infrared detector, the intensity of residual light after the processed mixed gas in the gas chamber absorbs the infrared light in the preset wavelength range; The data processing unit is used to convert the intensity of the residual light into the concentration of NF3.

[0016] In some embodiments, before the step of performing impurity removal treatment on gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect using a pretreatment unit, the method further includes: determining components of the gas decomposition products; and determining a preset frequency range based on the components to measure the concentration of NF3 using the preset frequency range.

[0017] In some embodiments, the components of the gas decomposition products are determined using a partial discharge simulation device; wherein the partial discharge simulation device comprises a housing, an air inlet pipe, an air outlet pipe, a pressure gauge, a vacuum pump, a needle-plate electrode, a protective resistor, a high-voltage non-corona experimental power supply, and an oscilloscope; The air inlet pipe and the air outlet pipe are respectively communicated with the interior of the housing, and the pressure gauge and the vacuum pump are respectively arranged on the air outlet pipe; The needle-plate electrode is arranged inside the housing, and the protective resistor, high-voltage non-corona experimental power supply and oscilloscope are arranged outside the housing; One end of the needle-plate electrode is connected to the high-voltage non-corona experimental power supply through the protection resistor, and the other end of the needle-plate electrode is connected to the oscilloscope; A cover plate is movably provided on the upper end of the shell.

[0018] In some embodiments, the step of determining the composition of the gas decomposition products using a partial discharge simulation device comprises: determining a partial discharge voltage of the partial discharge simulation device under inherent defects; Preset A preset strategy and a first preset strategy among the preset strategies as a target strategy, wherein the preset strategy includes a voltage value when the needle-plate electrode discharges and a preset discharge duration, wherein the voltage value is less than a partial discharge voltage under the inherent defect; Will The mixed gas is input into the housing through the air inlet pipe to a preset pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under the target strategy, and the discharge under the target strategy is detected. Gaseous decomposition products of mixed gases; The first The preset strategy is determined as the target strategy, and the above The mixed gas is input into the housing through the air inlet pipe to a preset pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under the target strategy, and the discharge under the target strategy is detected. the step of producing gaseous decomposition products of the mixed gas, wherein Take in turn A positive integer between .

[0019] In some embodiments, the step of determining a preset frequency range according to the component comprises: screening out characteristic decomposition products from the components of the gas decomposition products; A preset frequency range is determined according to the characteristic decomposition product.

[0020] In some embodiments, Before the mixed gas is input into the housing through the air inlet pipe to a preset pressure, the step further includes: filling high-purity Cleaning the interior of the partial discharge simulation device, repeating several times; and vacuuming the interior of the partial discharge simulation device.

[0021] In some embodiments, before the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy, the method further includes: will be charged into the The partial discharge simulation device of the mixed gas is allowed to stand for several hours; before and after the standing still, the internal pressure of the partial discharge simulation device is determined using a pressure gauge in the partial discharge simulation device; based on the internal pressure before and after the standing still, it is judged whether the interior of the partial discharge simulation device is airtight; if the airtightness is good, the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy is executed.

[0022] The present invention provides a method and device for detecting NF3, a characteristic decomposition product of mixed gases in electrical equipment. The device includes a pretreatment unit, a gas chamber, a non-dispersive infrared light source assembly, a narrowband filter, an optical path assembly, an infrared detector, and a data processing unit. The device is not only compact and portable, enabling real-time detection of NF3 gas at the work site, but also can accurately detect the concentration of NF3 gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The following is a schematic structural diagram of a device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, according to some embodiments; Figure 2 The following is a schematic structural diagram of a partial discharge simulation device provided according to some embodiments; Figure 3 An exemplary embodiment of a The concentration of gas generated changes with time; Figure 4 A frequency range diagram of a Fourier infrared device provided according to some embodiments is exemplarily shown; Figure 5 A diagram exemplarily shows a Fourier infrared detection result provided according to some embodiments; Figure 6 An example is shown according to Figure 5 The detection results of the Fourier infrared image and the text content corresponding to the diagram; Figure 7 A schematic structural diagram of an exhaust gas treatment device provided according to some embodiments is exemplarily shown. DETAILED DESCRIPTION

[0024] In order to better understand the above technical solution, the technical solution of this application is described in detail below through specific implementation methods.

[0025] To address the above-mentioned technical problems, the embodiments of the present application provide a method and apparatus for detecting NF3, a characteristic decomposition product of mixed gases in electrical equipment. The apparatus comprises a pretreatment unit, a gas chamber, a non-dispersive infrared light source assembly, a narrowband filter, an optical path assembly, an infrared detector, and a data processing unit. The apparatus is not only compact and portable, enabling real-time detection of NF3 gas at the work site, but also capable of accurately detecting the concentration of NF3 gas.

[0026] Figure 1 The following is a schematic structural diagram of a device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, according to some embodiments.

[0027] exist Figure 1In the present invention, the detection device for NF3, a characteristic decomposition product of mixed gas in electrical equipment, includes a preprocessing unit 1, a gas chamber 3, a non-dispersive infrared light source assembly 4, a narrowband filter 5, an optical path assembly 6, an infrared detector 7, and a data processing unit 8. The preprocessing unit 1 is connected to the gas chamber 3, specifically, via a gas pipeline; the non-dispersive infrared light source assembly 4 is connected to the optical path assembly 6 via the narrowband filter 5; and the infrared detector 7 is connected to the data processing unit 8.

[0028] The pre-treatment unit is used to remove impurities from the gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect to obtain a treated mixed gas, and then transport the treated mixed gas to the gas chamber.

[0029] In the embodiment of the present application, the impurity removal treatment is to remove moisture and large particles from the gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect, so that the gas entering the gas chamber does not contain moisture and large particles.

[0030] In the embodiment of the present application, the gas decomposition product of the SF6 / N2 mixed gas under the partial discharge defect can be a mixed gas obtained from SF6 / N2 mixed gas electrical equipment.

[0031] In some embodiments, a partial discharge simulation device is used to simulate a discharge defect (i.e., a partial discharge defect) in electrical equipment, and the gaseous decomposition products of SF6 / N2 produced during the partial discharge defect are determined. The characteristic decomposition product, NF3, is then screened from the gaseous decomposition products. In this embodiment of the present application, if the concentration of the characteristic decomposition product NF3 is detected to be greater than 0, the presence of a partial discharge defect is determined.

[0032] The structure of the partial discharge simulation device is described below.

[0033] In some embodiments, Figure 2 The following is a schematic diagram illustrating the structure of a partial discharge simulation device according to some embodiments. The partial discharge simulation device includes a housing 9, an air inlet pipe 10, an air outlet pipe 11, a pressure gauge 12, a vacuum pump 13, a needle-plate electrode 14, a protective resistor 15, a high-voltage non-corona test power supply 16, and an oscilloscope 17.

[0034] The air inlet pipe and the air outlet pipe are respectively communicated with the interior of the shell, and the pressure gauge and the vacuum pump are respectively arranged on the air outlet pipe.

[0035] In some embodiments, the air inlet duct and the air outlet duct are arranged on opposite sides of the housing. The mixed gas enters the shell from the air inlet pipe and is discharged from the shell from the air outlet pipe.

[0036] The pressure gauge is used to measure the gas pressure in the housing. The vacuum pump can extract gas from the interior of the housing to make the interior of the housing present a vacuum state.

[0037] The needle-plate electrode is arranged inside the shell, and the protective resistor, high-voltage no-corona experimental power supply and oscilloscope are arranged outside the shell; in this embodiment, the high-voltage no-corona experimental power supply provides electrical energy to the needle-plate electrode, so that the needle-plate electrode can discharge in the discharge chamber 20.

[0038] One end of the needle-plate electrode is connected to the high-voltage non-corona experimental power supply through the protective resistor, and the other end of the needle-plate electrode is connected to the oscilloscope. The oscilloscope is used to display the discharge voltage of the needle-plate electrode.

[0039] A cover plate is movably provided on the upper end of the shell. The cover plate is movably provided on the upper end of the shell. The cover plate can be removed from the upper end of the shell as needed, or can be covered on the upper end of the shell.

[0040] In this embodiment, The mixed gas is fed into the housing through the air inlet pipe, the needle-plate electrode is energized, samples are taken through the air outlet pipe at preset intervals, and the sampled gas is detected using a gas chromatograph-mass spectrometer.

[0041] In the embodiment of the present application, an exhaust gas treatment device can be added, which can treat the gas detected by the gas chromatography-mass spectrometry instrument.

[0042] After building the partial discharge simulation device, the characteristic decomposition products are determined using the partial discharge simulation device.

[0043] Specifically, the method further includes: determining, by the partial discharge simulation device, a characteristic decomposition product NF3 for identifying partial discharge defects of the electrical equipment; The step of determining the characteristic decomposition product NF3 for identifying partial discharge defects of electrical equipment by the partial discharge simulation device includes S101 to S105. Steps S101 to S104 are steps of determining the components of the gas decomposition products by using the partial discharge simulation device.

[0044] S101. Determine the partial discharge voltage of the partial discharge simulation device under inherent defects.

[0045] The step of determining the partial discharge voltage of the partial discharge simulation device under inherent defects comprises: The mixed gas is input into the shell through the air inlet pipe to a preset air pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device is at a target voltage to determine whether the needle-plate electrode is broken down.

[0046] In this embodiment, in the process of determining the partial discharge voltage under the inherent defect The mixed gas is filled into the preset pressure in the housing and the pressure in step S103 The preset pressure of the mixed gas in the shell is the same after it is filled. In mixed gas and The mixing ratio and the partial discharge simulation device charged in step S103 The mixing ratio of the mixed gas is the same. In addition, the humidity and temperature of the partial discharge simulation device are also the same as the temperature and humidity of the partial discharge simulation device in step S103.

[0047] If breakdown occurs, the target voltage can be lowered. The mixed gas is input into the shell through the air inlet pipe to a preset gas pressure, and the high-voltage non-corona experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges at a target voltage until the needle-plate electrode does not break down at the target voltage, and the target electrode is determined as the partial discharge voltage under inherent defects.

[0048] In this embodiment, the target voltage is set based on experience, assuming the needle-plate electrode will not breakdown. For example, the target voltage can be set to 40 kV. However, since this is based on experience, the target voltage may not be accurate. Actual testing using a partial discharge simulator is necessary to determine the partial discharge voltage under inherent defects. In the embodiments of this application, actual testing found that setting the target voltage to 40 kV did not result in a needle-plate voltage breakdown. Therefore, 40 kV was set as the partial discharge voltage under inherent defects.

[0049] S102, pre-setting A preset strategy and The first preset strategy among the preset strategies is used as the target strategy, wherein the preset strategy includes a voltage value when the needle-plate electrode discharges and a preset discharge duration, wherein the voltage value is less than the local discharge voltage under the inherent defect.

[0050] For example, The preset strategy can be four preset strategies, wherein the first preset strategy includes a voltage value of 10kV during needle-plate electrode discharge, and a preset discharge time of 10 hours; the second preset strategy includes a voltage value of 12kV during needle-plate electrode discharge, and a preset discharge time of 10 hours; the third preset strategy includes a voltage value of 18kV during needle-plate electrode discharge, and a preset discharge time of 10 hours; the fourth preset strategy includes a voltage value of 18kV during needle-plate electrode discharge starting from 10kV, increasing by 0.5kV per hour until the voltage reaches 15kV, and the preset discharge time is 10 hours.

[0051] In the embodiment of the present application, in order to prevent the needle-plate electrode from being broken down, which would affect the process of determining the characteristic decomposition products used to identify the partial discharge defects of electrical equipment, the target voltage at which the needle-plate electrode cannot be broken down, that is, the partial discharge voltage under the inherent defect, is first determined. The voltage values of the needle-plate electrode discharge in each preset strategy are all lower than the local discharge voltage under inherent defects.

[0052] S103, will The mixed gas is input into the housing through the air inlet pipe to a preset pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under the target strategy, and the discharge under the target strategy is detected. Gaseous decomposition products of mixed gases.

[0053] In the embodiments of the present application, in order to ensure the accuracy of the experimental results, that is, to determine the characteristic decomposition products, the temperature and humidity of the laboratory where the partial discharge simulation device is located are controlled during the experiment, and are exemplarily maintained at 20±2°C and 50±3% relative humidity.

[0054] In some embodiments, Before the mixed gas is input into the housing through the air inlet pipe to a preset pressure, the step further includes: filling high-purity Cleaning the interior of the partial discharge simulation device, repeating several times; and vacuuming the interior of the partial discharge simulation device.

[0055] For example, high purity The internal pressure of the partial discharge simulator is raised to 0.2-0.3 MPa, and the interior of the partial discharge simulator is cleaned three times. This ensures that all gas impurities in the partial discharge simulator are completely discharged, ensuring the accuracy and reliability of subsequent experiments.

[0056] In some embodiments, high purity Before repeating the step of cleaning the interior of the partial discharge simulator several times, the method further includes: removing the cover and wiping the interior of the partial discharge simulator with an antistatic dust-free cloth moistened with anhydrous ethanol to ensure that the interior walls of the partial discharge simulator are clean and free of impurities to avoid any impact on the experimental results. The cover is then reinstalled on the upper end of the partial discharge simulator, and the interior of the partial discharge simulator is evacuated to ensure good airtightness.

[0057] In some embodiments, before the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy, the method further includes: will be charged into the The partial discharge simulation device of the mixed gas is allowed to stand for several hours; before and after the standing still, the internal pressure of the partial discharge simulation device is determined using a pressure gauge in the partial discharge simulation device; based on the internal pressure before and after the standing still, it is judged whether the interior of the partial discharge simulation device is airtight; if the airtightness is good, the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy is executed.

[0058] In some embodiments, after the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy, the method further includes: The interior of the partial discharge simulation device is evacuated and filled with The interior of the partial discharge simulation device is cleaned, and the process is repeated several times.

[0059] In this embodiment, after each execution according to the target strategy, that is, after each set of experiments, the contents of the partial discharge simulation device are evacuated to -0.1 MPa and filled with nitrogen at a pressure of 0.3 to 0.4 MPa. The cleaning is repeated three times to avoid the release of residual decomposition gas when the cover is opened to ensure the safety of the experimenters.

[0060] In this embodiment, the detection of discharge under the preset strategy The gas decomposition products of the mixed gas can be collected once every hour using a Teflon sampling bag in the partial discharge simulation device. Gaseous decomposition products of mixed gases. Gas chromatography-mass spectrometry is used to detect the gaseous decomposition products and to perform qualitative and quantitative analysis on the gaseous decomposition products.

[0061] S104, the The preset strategy is determined as the target strategy, and the above The mixed gas is input into the housing through the air inlet pipe to a preset pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under the target strategy, and the discharge under the target strategy is detected. the step of producing gaseous decomposition products of the mixed gas, wherein Take in turn A positive integer between .

[0062] In the embodiment of the present application, since there may be multiple preset strategies, it is necessary to set the heating time under each preset strategy. The gas decomposition products of the mixed gas are detected.

[0063] S105, from the From the decomposition products of the mixed gas, characteristic decomposition products for identifying partial discharge defects are screened out. That is, characteristic decomposition products are screened out from the decomposition products of the gas.

[0064] mentioned above In the example of four preset strategies, the decomposition products detected under partial discharge conditions in this experiment are 、 、 、 、 and The three main decomposition products with the highest concentrations are 、 and . Only at the voltage of 18kV, the generation was detected at the 9th and 10th hours of partial discharge, with concentrations of 0.326μL / L and 0.679μL / L, respectively. It only occurs when the discharge is intense and lasts for a long time. and The gas production concentration did not exceed 1μL / L, and had a certain degree of dispersion, so it was not suitable for analysis as a characteristic product. Gas was not detected in the overheating test products and is a characteristic product under partial discharge conditions. The generation of gas can be used as a characteristic identification product of partial discharge defects, that is, a characteristic decomposition product, and Gas can be used as Mixed gas is different from pure Characteristic decomposition products of gases. The concentration of gas generated changes with time as follows Figure 4 shown.

[0065] In the embodiments of the present application, the gas chamber is a space containing the gas sample to be tested, namely, the gaseous decomposition products of the SF6 / N2 mixture under partial discharge defects. The gas chamber ensures that the gas sample to be tested remains stably within a specific area during the testing process, facilitating the smooth passage of infrared light emitted by the non-dispersive infrared light source assembly through the gas sample to be tested.

[0066] The non-dispersive infrared light source assembly is used to emit infrared light, so that the infrared light passes through a narrowband filter to obtain infrared light in a preset wavelength frequency range. The infrared light in the preset frequency range enters the air chamber through the optical path assembly. The preset frequency range is 980~1060cm -1 .

[0067] In some embodiments, before using a pre-processing unit to remove impurities from gas decomposition products of the SF6 / N2 mixed gas under a partial discharge defect, components of the gas decomposition products are determined, and a preset frequency range is determined based on the components. In some embodiments, determining the preset frequency range based on the components includes screening characteristic decomposition products from the components of the gas decomposition products, and determining the preset frequency range based on the characteristic decomposition products.

[0068] Specifically, the decomposition products detected under partial discharge conditions are 、 、 、 、 and As a component of the gas decomposition product. Determining the preset frequency range based on the component may include searching the infrared absorption spectra of all components in the NIST database, determining the absorption peaks of other components different from NF3 gas, and determining the frequency range of the absorption peaks of other components different from NF3 gas as the preset frequency range. Specifically, NF3 gas has the absorption peaks of 880-990 cm and 980-1060 cm -1 There are two strong absorption peaks at 980~1060cm. Compared with the infrared absorption spectra of other gases, it is found that other gases have two strong absorption peaks at 980~1060cm -1 The absorption peak at is very small, so the preset frequency range is determined to be 980~1060cm -1 .

[0069] To further verify that the above preset frequency range can accurately identify NF3 gas, an actual experiment was conducted. Specifically, a standard gas containing NF3 gas was introduced into a Fourier transform infrared spectroscopy (FTIR) device for analysis, where the mixed standard gas included most of the decomposition products of SF6 / N2. The NF3 concentration in the standard gas was 52ppm. Subsequently, the frequency range of the Fourier infrared device was adjusted to 980 to 1060cm -1 (like Figure 4 As shown in Figure 2), this range includes the characteristic absorption peak of NF3 gas. By measuring and analyzing the infrared absorption signal in this frequency range, the NF3 concentration result is obtained (the detection result of Fourier infrared is shown in Figure 2). Figure 5 and Figure 6 The results show that the infrared wavelength at this wavelength is suitable for detecting NF3 gas in the decomposition products of SF6 / N2 gas.

[0070] The narrowband filter is used to selectively allow only infrared light with the characteristic absorption wavelength of NF3 gas to pass through, while filtering out light of other wavelengths. Specifically, the preset frequency range of infrared light with the characteristic absorption wavelength of NF3 gas is 980~1060cm -1 .

[0071] The optical path component is used to ensure that the infrared light emitted by the non-dispersive infrared light source component and the infrared light in a preset wavelength frequency range obtained after being processed by the narrowband filter can pass smoothly through the gas sample to be tested in the gas chamber.

[0072] The infrared detector is used to detect the intensity of the remaining light after the processed mixed gas in the gas chamber absorbs the infrared light in the preset wavelength range.

[0073] In this embodiment, as the treated mixed gas enters the gas chamber, the optical path assembly directs infrared light from the non-dispersive infrared light source assembly into the chamber. The treated mixed gas then absorbs infrared light within a predetermined wavelength range. Because higher NF3 gas concentrations absorb more infrared light within the predetermined frequency range, the intensity of the remaining light received by the infrared detector decreases.

[0074] A data processing unit is used to convert the intensity of the residual light into the concentration of NF3.

[0075] In this embodiment, the data processing unit calculates the NF3 concentration by comparing the residual light intensity with a reference light intensity. The infrared detector is electrically connected to the data processing unit. The residual light intensity is an electrical signal, and the NF3 concentration is calculated based on this electrical signal and a calibration curve. The calibration curve includes reference light intensity and corresponding NF3 concentrations. After finding a reference light intensity that matches the residual light intensity, the NF3 concentration corresponding to this reference light intensity is searched for and used as the NF3 concentration obtained by converting the residual light intensity.

[0076] The device in the embodiment of the present application includes a preprocessing unit, a gas chamber, a non-dispersive infrared light source assembly, a narrowband filter, an optical path assembly, an infrared detector and a data processing unit. The device is not only compact and easy to carry, but also realizes real-time detection of NF3 gas at the work site and can accurately detect the concentration of NF3 gas.

[0077] In some embodiments, the device further comprises a flow control unit 2, which is connected to a data processing unit. The data processing unit can control the flow control unit to adjust the flow of the gas decomposition products entering the gas chamber.

[0078] In this embodiment, the flow rate of the gas decomposition products entering the gas chamber can be adjusted according to actual needs.

[0079] In some embodiments, the device also includes a first temperature sensor and a first temperature controller; the data processing unit is also used to obtain the first temperature in the air chamber detected by the first temperature sensor; when the first temperature is not within a first preset temperature range, the first temperature controller is used to control the first temperature adjustment device to adjust the first temperature in the air chamber to within the first preset temperature range.

[0080] In the above embodiment of the present application, a first temperature sensor is disposed within the air chamber to detect a first temperature within the air chamber. A first thermostat is connected to the first sensor, and the first thermostat is also connected to a first temperature regulating device. The first temperature regulating device may be a heating and cooling device.

[0081] In the embodiment of the present application, the first temperature sensor, the first temperature controller and the first temperature adjustment device can ensure that the temperature in the air chamber remains unchanged, reducing the impact of temperature on detection accuracy.

[0082] In some embodiments, the device further includes an exhaust gas treatment device; the exhaust gas treatment device is used to perform exhaust gas treatment on the gas in the gas chamber.

[0083] In the embodiment of the present application, since harmful substances may exist in the gas decomposition products, in order to prevent the harmful substances from polluting the atmosphere, the embodiment of the present application performs tail gas treatment on the gas in the gas chamber.

[0084] In some embodiments, Figure 7 The following is a schematic diagram of the structure of an exhaust gas treatment device according to some embodiments. The exhaust gas treatment device includes an SF6 membrane separation technology unit 91, a catalytic device 92, an adsorption device 93, an alkaline solution washing device 94, and a condensation adsorption device 95 connected in sequence. The SF6 membrane separation technology unit is used to perform membrane separation technology on the gas in the gas chamber to obtain SF6 gas and other gases.

[0085] Membrane separation technology uses a selective permeable membrane to separate SF6 from other gases. Membrane separation technology can efficiently separate SF6 while allowing other gases to pass through.

[0086] In some embodiments, the tail gas treatment device further includes a compression condensation device 96 and an SF6 collection device 97 connected in sequence, and the compression condensation device is connected to the SF6 membrane separation technology unit; The compression condensation device is used to compress and condense the SF6 gas; The SF6 collecting device is used to collect the compressed and condensed SF6 gas.

[0087] In this embodiment, the SF6 membrane separation technology unit is connected to the SF6 collection device via a compression condensation device. In this embodiment, the SF6 gas obtained by the membrane separation technology is compressed and condensed, liquefied and stored in a high-pressure container.

[0088] The catalytic device is used to perform catalytic oxidation treatment on the other gases to obtain catalytically oxidized gases.

[0089] In this embodiment, the catalytic oxidation treatment may be to oxidize the combustible gases such as H2, CH4, CO in the gas decomposition products into harmless H2O and CO2 using a catalyst. The catalyst may be a platinum catalyst or a palladium catalyst.

[0090] The adsorption device is used to perform adsorption treatment on the gas after the catalytic oxidation to obtain adsorbed gas.

[0091] Adsorption treatment can be achieved by using activated carbon or molecular sieve to adsorb harmful gases such as H2S, SO2, CS2, etc.

[0092] The alkaline solution washing device is used to perform alkaline solution washing on the gas after the adsorption to obtain alkaline solution washed gas; The alkaline solution washing treatment can be to neutralize acidic gases such as SO2, SOF2 and SO2F2 by using alkaline solution.

[0093] The condensation adsorption device is used to condense and adsorb the gas after washing with the alkali solution to obtain the final gas.

[0094] In this embodiment, in order to prevent the harmful gas treatment unit from failing to remove all the harmful gases, the gas after washing with the alkali solution is further condensed and adsorbed to further remove the harmful gases.

[0095] In some embodiments, the device further includes an exhaust gas detection device 98; the exhaust gas detection device is connected to the condensation adsorption device, and the exhaust gas detection device is connected to the data processing unit; The exhaust gas detection device is used to detect the final gas and obtain a detection result; The data processing unit is further configured to determine whether the detection result meets the standard; if the detection result meets the standard, the final gas is discharged; if the detection result does not meet the standard, the final gas is further processed.

[0096] In this embodiment, the final gas test results are monitored in real time to see if they meet the standards. If they do, the discharge valve automatically opens, allowing the final gas to be discharged directly. If they do not, the discharge valve remains closed, while the valve of the intake device opens, directing the final gas into the catalytic device 92 for secondary treatment.

[0097] In some embodiments, the standard may refer to environmental protection requirements, which may specify requirements for gas emissions.

[0098] In some embodiments, the device also includes a second temperature sensor and a second temperature controller; the data processing unit is also used to obtain the second temperature around the infrared detector detected by the second temperature sensor; when the second temperature is not within the second preset temperature range, the second temperature controller is used to control the second temperature adjustment device to adjust the second temperature around the infrared detector to the second preset temperature range.

[0099] In an embodiment of the present application, a second temperature sensor is disposed around the infrared detector to sense a second temperature around the infrared detector in real time. The second temperature sensor is connected via a second thermostat and a second temperature control device. The second temperature control device may be a heating or cooling device. In some embodiments, the first and second thermostats may be the same thermostat, which can simultaneously control both the first and second temperature control devices.

[0100] In the embodiment of the present application, the second temperature sensor, the second temperature controller and the second temperature adjustment device can ensure that the ambient temperature of the infrared detector remains unchanged, thereby reducing the impact of temperature on detection accuracy.

[0101] In some embodiments, the device further includes a constant temperature chamber; the gas chamber and the infrared detector are located in the constant temperature chamber.

[0102] In this embodiment, the constant temperature chamber is a space that at least accommodates the air chamber and the infrared detector, and the temperature in the constant temperature chamber remains constant, which can further reduce the influence of temperature on detection accuracy.

[0103] In some embodiments, the device may further include a display unit connected to the data processing unit. The display unit may display the concentration of NF3 and the temperature data detected by the first temperature sensor and the second temperature sensor.

[0104] In the embodiments of the present application, the constant temperature chamber, the first temperature sensor, the first thermostat, the first temperature adjustment device, the second temperature sensor, the second thermostat, and the second temperature adjustment device enable the gas chamber and infrared detector to operate at a constant temperature, reducing the impact of temperature changes on detection accuracy. The exhaust gas treatment device effectively collects the decomposition products of the test gas and achieves environmental protection requirements through separation, recovery, and treatment of harmful gases.

[0105] The device in the examples of this application overcomes existing technical barriers, enabling the measurement of NF₃ gas in the decomposition products of SF₆ / N₂ mixed gases. Furthermore, the device is compact and portable, enabling real-time on-site detection of NF₃ gas. Its compact design not only facilitates use in a variety of environments but also ensures the efficiency and reliability of the detection process, enabling accurate measurement results without relying on large laboratory equipment. This portability makes it particularly suitable for applications requiring frequent movement or testing at multiple locations, greatly enhancing operational flexibility and convenience.

[0106] The present application also provides a method for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, and a device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, comprising: Using a pretreatment unit to remove impurities from gas decomposition products of the SF6 / N2 mixed gas under partial discharge defects to obtain a treated mixed gas, and transporting the treated mixed gas to a gas chamber; The infrared light is emitted by a non-dispersive infrared light source assembly, so that the infrared light passes through the narrowband filter to obtain infrared light in a preset frequency range. The infrared light in the preset frequency range passes through the optical path assembly and enters the air chamber. The preset frequency range is 980~1060cm -1 ; detecting, using an infrared detector, the intensity of residual light after the processed mixed gas in the gas chamber absorbs the infrared light in the preset wavelength range; The data processing unit is used to convert the intensity of the residual light into the concentration of NF3.

[0107] In some embodiments, before the step of using a pretreatment unit to remove impurities from the gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect, the step further includes: determining the components of the gas decomposition products; determining a preset frequency range based on the components, so as to measure the concentration of NF3 using the preset frequency range.

[0108] The contents of the methods in the embodiments of the present application have been described in detail in the above device description and will not be repeated here.

[0109] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application. The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application. These improvements and variations should also be regarded as the scope of protection of the present application.

Claims

1. A device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, characterized in that: The invention comprises a pre-processing unit, an air chamber, a non-dispersive infrared light source assembly, a narrowband filter, an optical path assembly, an infrared detector and a data processing unit, wherein the pre-processing unit is connected to the air chamber; the non-dispersive infrared light source assembly is connected to the optical path assembly via the narrowband filter; and the infrared detector is connected to the data processing unit; The pre-treatment unit is used to remove impurities from the gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect to obtain a treated mixed gas, and to transport the treated mixed gas to the gas chamber; The non-dispersive infrared light source assembly is used to emit infrared light, so that the infrared light passes through the narrowband filter to obtain infrared light in a preset frequency range, and the infrared light in the preset frequency range passes through the optical path assembly into the air chamber, and the preset frequency range is 980~1060cm -1 ; The infrared detector is used to detect the intensity of the residual light after the processed mixed gas in the gas chamber absorbs the infrared light in the preset wavelength range; The data processing unit is used to convert the intensity of the residual light into the concentration of the characteristic decomposition product NF3 under the partial discharge defect.

2. The device according to claim 1, characterized in that It also includes a first temperature sensor and a first temperature controller; the data processing unit is also used to obtain the first temperature in the air chamber detected by the first temperature sensor; when the first temperature is not within a first preset temperature range, the first temperature controller is used to control the first temperature adjustment device to adjust the first temperature in the air chamber to within the first preset temperature range.

3. The device according to claim 1, characterized in that It also includes an exhaust gas treatment device; the exhaust gas treatment device is used to treat the gas in the air chamber.

4. The device according to claim 3, characterized in that The tail gas treatment device includes an SF6 membrane separation technology unit, a catalytic device, an adsorption device, an alkaline solution washing device and a condensation adsorption device connected in sequence; The SF6 membrane separation technology unit is used to perform membrane separation technology on the gas in the gas chamber to obtain SF6 gas and other gases; The catalytic device is used to perform catalytic oxidation treatment on the other gas to obtain catalytically oxidized gas; The adsorption device is used to perform adsorption treatment on the gas after catalytic oxidation to obtain adsorbed gas; The alkaline solution washing device is used to perform alkaline solution washing on the gas after the adsorption to obtain alkaline solution washed gas; The condensation adsorption device is used to condense and adsorb the gas after washing with the alkali solution to obtain the final gas.

5. The device according to claim 4, characterized in that The exhaust gas treatment device further includes an exhaust gas detection device; the exhaust gas detection device is connected to the condensation adsorption device, and the exhaust gas detection device is connected to the data processing unit; The exhaust gas detection device is used to detect the final gas and obtain a detection result; The data processing unit is further configured to determine whether the detection result meets the standard; if the detection result meets the standard, the final gas is discharged; if the detection result does not meet the standard, the final gas is further processed.

6. The device according to claim 4, characterized in that The tail gas treatment device further comprises a compression condensation device and an SF6 collection device connected in sequence, and the compression condensation device is connected to the SF6 membrane separation technology unit; The compression condensation device is used to compress and condense the SF6 gas; The SF6 collecting device is used to collect the compressed and condensed SF6 gas.

7. The device according to claim 1, characterized in that It also includes a second temperature sensor and a second temperature controller; the data processing unit is also used to obtain the second temperature around the infrared detector detected by the second temperature sensor; when the second temperature is not within a second preset temperature range, the second temperature controller is used to control the second temperature adjustment device to adjust the second temperature around the infrared detector to within the second preset temperature range.

8. The device according to claim 1, characterized in that It also includes a constant temperature chamber; the air chamber and the infrared detector are located in the constant temperature chamber.

9. A method for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment, applied to the device for detecting NF3, a characteristic decomposition product of mixed gas in electrical equipment according to claim 1, characterized in that: include: Using a pretreatment unit to remove impurities from gas decomposition products of the SF6 / N2 mixed gas under partial discharge defects to obtain a treated mixed gas, and transporting the treated mixed gas to a gas chamber; The infrared light is emitted by a non-dispersive infrared light source assembly, so that the infrared light passes through the narrowband filter to obtain infrared light in a preset frequency range. The infrared light in the preset frequency range passes through the optical path assembly and enters the air chamber. The preset frequency range is 980~1060cm -1 ; detecting, using an infrared detector, the intensity of residual light after the processed mixed gas in the gas chamber absorbs the infrared light in the preset wavelength range; The data processing unit is used to convert the intensity of the residual light into the concentration of NF3.

10. The method according to claim 9, characterized in that Before the step of using the pretreatment unit to remove impurities from the gas decomposition products of the SF6 / N2 mixed gas under the partial discharge defect, the method also includes: determining the components of the gas decomposition products; determining a preset frequency range based on the components, and measuring the concentration of NF3 using the preset frequency range.

11. The method according to claim 10, characterized in that Determine the components of the gas decomposition products using a partial discharge simulation device, wherein the partial discharge simulation device includes a housing, an air inlet pipe, an air outlet pipe, a pressure gauge, a vacuum pump, a needle-plate electrode, a protective resistor, a high-voltage non-corona experimental power supply, and an oscilloscope; The air inlet pipe and the air outlet pipe are respectively communicated with the interior of the housing, and the pressure gauge and the vacuum pump are respectively arranged on the air outlet pipe; The needle-plate electrode is arranged inside the housing, and the protective resistor, high-voltage non-corona experimental power supply and oscilloscope are arranged outside the housing; One end of the needle-plate electrode is connected to the high-voltage non-corona experimental power supply through the protection resistor, and the other end of the needle-plate electrode is connected to the oscilloscope; A cover plate is movably provided on the upper end of the shell.

12. The method according to claim 11, characterized in that The step of determining the composition of the gas decomposition products using a partial discharge simulation device comprises: determining a partial discharge voltage of the partial discharge simulation device under inherent defects; Preset A preset strategy and a first preset strategy among the preset strategies as a target strategy, wherein the preset strategy includes a voltage value when the needle-plate electrode discharges and a preset discharge duration, wherein the voltage value is less than a partial discharge voltage under the inherent defect; Will The mixed gas is input into the housing through the air inlet pipe to a preset pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under the target strategy, and the discharge under the target strategy is detected. Gaseous decomposition products of mixed gases; The first The preset strategy is determined as the target strategy, and the above The mixed gas is input into the housing through the air inlet pipe to a preset pressure, and the high-voltage corona-free experimental power supply is controlled to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under the target strategy, and the discharge under the target strategy is detected. the step of producing gaseous decomposition products of the mixed gas, wherein Take in turn A positive integer between .

13. The method according to claim 12, characterized in that The step of determining the preset frequency range according to the components comprises: screening out characteristic decomposition products from the components of the gas decomposition products; A preset frequency range is determined according to the characteristic decomposition product.

14. The method according to claim 12, characterized in that In the said Before the mixed gas is input into the housing through the air inlet pipe to a preset pressure, the step further includes: filling high-purity Cleaning the interior of the partial discharge simulation device, repeating several times; and vacuuming the interior of the partial discharge simulation device.

15. The method according to claim 12, characterized in that Before the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy, the method further includes: will be charged into the The partial discharge simulation device of the mixed gas is allowed to stand for several hours; before and after the standing still, the internal pressure of the partial discharge simulation device is determined using a pressure gauge in the partial discharge simulation device; based on the internal pressure before and after the standing still, it is judged whether the interior of the partial discharge simulation device is airtight; if the airtightness is good, the step of controlling the high-voltage corona-free experimental power supply to be energized so that the needle-plate electrode in the partial discharge simulation device discharges under a target strategy is executed.

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