WO2023087887A1 - Distributed online monitoring system and method for sulfur hexafluoride decomposition product - Google Patents

Distributed online monitoring system and method for sulfur hexafluoride decomposition product Download PDF

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Publication number
WO2023087887A1
WO2023087887A1 PCT/CN2022/119773 CN2022119773W WO2023087887A1 WO 2023087887 A1 WO2023087887 A1 WO 2023087887A1 CN 2022119773 W CN2022119773 W CN 2022119773W WO 2023087887 A1 WO2023087887 A1 WO 2023087887A1
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optical fiber
light source
detection
photoacoustic
excitation light
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PCT/CN2022/119773
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French (fr)
Chinese (zh)
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马凤翔
陈珂
邱欣杰
赵新瑜
李辰溪
赵跃
朱峰
赵恒阳
杭忱
袁小芳
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国网安徽省电力有限公司电力科学研究院
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Publication of WO2023087887A1 publication Critical patent/WO2023087887A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
    • G01N2021/1704—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids in gases

Definitions

  • the invention relates to the technical fields of optical fiber acoustic wave sensing and photoacoustic spectroscopy, and more specifically relates to a distributed on-line monitoring system and method for decomposition products of sulfur hexafluoride.
  • Photoacoustic spectroscopy has become an effective method in the field of detection of trace gases.
  • Photoacoustic spectroscopy has the advantages of high sensitivity, no background detection, fast response, and no electromagnetic interference.
  • the main principle is based on the selective absorption of gas molecules and the Lambert-Beer law.
  • the photoacoustic effect of gases can be explained by three steps: 1. Gas molecules absorb excitation light of a specific wavelength and transition from the ground state to the excited state; 2. . Molecules in the excited state transition back to the ground state without radiation, releasing heat and causing the surrounding gas to expand; 3.
  • Optical fiber acoustic wave sensing is a new acoustic wave detection technology. Its basic principle is to use light as a detection signal to sense changes in physical quantities such as external temperature, strain, and pressure through an acoustic wave sensitive diaphragm, and react to optical parameters. Detection of external physical quantities. This method has the advantages of anti-electromagnetic interference, long-distance measurement, and distributed detection.
  • the technical problem to be solved by the present invention is that the prior art optical fiber photoacoustic sensing scheme has the limitations of a single excitation light source and fixed application scenarios, and cannot meet the demand for multi-component gas detection of sulfur hexafluoride electrical equipment.
  • a distributed on-line monitoring system for sulfur hexafluoride decomposition products including a first excitation light source device emitting ultraviolet light, a second excitation light source device emitting near-infrared light, and a detection system.
  • a light source device, an optical fiber array (15) and multiple groups of optical fiber photoacoustic sensing probes the detection light source device emits broad-spectrum light for detecting photoacoustic signals, and each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area, One end of each group of optical fiber photoacoustic sensing probes is respectively connected to the first excitation light source device through an optical fiber array (15), and one end of each group of optical fiber photoacoustic sensing probes is respectively connected to the second excitation light source device through an optical fiber array (15), The other end of each group of optical fiber photoacoustic sensing probes is respectively connected to the detection light source device through the optical fiber array (15); the first excitation light source device emitting ultraviolet light is used to detect SO in SF 6 electrical equipment, and emits near-infrared light The second excitation light source device is used to detect H 2 S in SF 6 electrical equipment, by selectively connecting one group of excitation light source devices or by time-sharing two groups of excitation light
  • Each group of optical fiber photoacoustic sensing probes is placed in different monitoring areas. By selecting one of the monitoring areas or connecting multiple monitoring areas in time The fiber optic photoacoustic sensing probe realizes gas detection in one monitoring area or time-sharing detection of gas in multiple monitoring areas, and the whole system performs distributed detection.
  • the present invention is provided with a first excitation light source device and a second excitation light source device, and there are many laser light sources, and the SO in SF6 electrical equipment is detected by the first excitation light source device emitting ultraviolet light, and by the second excitation light source device emitting near-infrared light
  • the light source device detects H 2 S in SF 6 electrical equipment, and realizes separate detection of SO 2 gas, single detection of H 2 S gas or SO 2.
  • Time-sharing detection of H 2 S gas realize gas detection in one monitoring area or gas time-sharing in multiple monitoring areas by selecting to connect to one monitoring area or time-sharing connecting the corresponding optical fiber photoacoustic sensing probes of multiple monitoring areas Detection, application scenarios are not limited and meet the needs of multi-component gas detection of sulfur hexafluoride electrical equipment.
  • the first excitation light source device includes a laser light source (5) and a collimator lens (17), the laser light source (5) emits a laser beam of a specific wavelength, and the beam is converged and split by the collimator lens (17).
  • the bundles are coupled to each input end of the optical fiber array (15), and each output end of the optical fiber array (15) is connected to one end of each group of optical fiber photoacoustic sensing probes in one-to-one correspondence.
  • the second excitation light source device includes a laser drive circuit (16), a semiconductor laser (1), an erbium-doped fiber amplifier (4) and a first optical switch (6), and the laser drive circuit (16) drives the semiconductor
  • the laser (1) makes it emit laser light of a specific wavelength to enter the erbium-doped fiber amplifier (4), and the erbium-doped fiber amplifier (4) amplifies the optical power, and the amplified laser light enters the first optical switch (6), and the first optical switch
  • Each output channel of (6) is respectively one-to-one correspondingly connected with the input port of optical fiber array (15), and each output end of optical fiber array (15) is respectively connected with one end of each group of optical fiber photoacoustic sensing probes one-to-one correspondingly.
  • the semiconductor laser 1 is a near-infrared DFB laser with a central wavelength of 1530nm.
  • the detection light source device includes a fiber optic broadband light source (7), a fiber optic circulator (8), a second optical switch (9), a spectrometer (10) and an industrial computer (11), and the fiber optic broadband light source ( 7)
  • the emitted broadband light enters the second optical switch (9) through the optical fiber circulator (8), and each output channel of the second optical switch (9) corresponds to the other channel of each group of optical fiber photoacoustic sensing probes one by one.
  • One end is connected, and the interference spectrum generated in each group of optical fiber photoacoustic sensing probes is returned from the optical fiber array (15) to the second optical switch (9) and output to the spectrometer (10) through the optical fiber circulator (8), and the industrial computer (11 ) collect the spectrum detected by the spectrometer (10) and perform signal processing and display.
  • the signal processing and display includes: demodulating the spectrum by using high-speed spectrum demodulation method to obtain the dynamic cavity length of the interference cavity, and obtaining the amplitude of the photoacoustic signal by measuring the cavity length change of the interference cavity, and according to the photoacoustic signal The proportional relationship between the magnitude of the gas concentration and the gas concentration is obtained and displayed.
  • the optical fiber broadband light source (10) is a near-infrared superluminescent light-emitting diode SLED or an amplified spontaneous emission ASE light source.
  • optical fiber photoacoustic sensing probes which are respectively the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe ( 14), the number of output ends of the optical fiber array (15) is greater than or equal to the number of optical fiber photoacoustic sensing probes, the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) And the third optical fiber photoacoustic sensing probe (14) is respectively connected to one output end of the optical fiber array (15).
  • the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe (14) have the same structure, and all include acoustic wave sensitive diaphragms (18), air chamber (19), optical fiber end face (20), optical fiber collimator (21) and shell (22), in the described shell (22) parallel arrangement fiber end face (20) and optical fiber collimator (21 ), the fiber end face (20) and the fiber collimator (21) have the same shape and one end of the fiber end face (20) extends out of the shell (22) and a fiber probe is connected with the detection light source device through the fiber array (15), and the fiber collimator One end of the straight device (21) extends an optical fiber probe to the outer casing (22) and is connected with the exciting light source device through the optical fiber array (15);
  • the tube is arranged horizontally and one end is connected with the other end of the optical fiber collimator (21), the air guide channel is arranged vertically and the upper end communicates with the
  • the cantilever beam structure (181) is a rectangular groove with a free end downward, and the external gas to be measured diffuses into the gas chamber (19) through the slot of the cantilever beam structure (181) on the acoustic wave sensitive diaphragm (18).
  • the present invention also provides a method for a distributed on-line monitoring system of sulfur hexafluoride decomposition products, the first excitation light source device emitting ultraviolet light is used to detect SO2 in SF6 electrical equipment, and the second excitation device emitting near-infrared light
  • the light source device is used to detect H 2 S in SF 6 electrical equipment, and realize the separate detection of SO 2 gas and H 2 S gas by selectively connecting one group of excitation light source devices or two groups of excitation light source devices in time-sharing Or for time-sharing detection of SO 2 and H 2 S gas, each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area, and by selecting to connect one of the monitoring areas or connecting multiple monitoring areas corresponding to the optical fiber photoacoustic sensor
  • the sensor probe realizes gas detection in one monitoring area or gas time-sharing detection in multiple monitoring areas, and the whole system performs distributed detection.
  • the present invention is provided with the first excitation light source device and the second excitation light source device, and the laser light source is more, by the first excitation light source device of emitting ultraviolet light, SO in SF6 electrical equipment is detected, by emitting near-infrared light
  • the second excitation light source device detects H 2 S in SF 6 electrical equipment, and realizes separate detection of SO 2 gas and separate detection of H 2 S gas by selectively connecting one group of excitation light source devices or connecting two groups of excitation light source devices in time-sharing.
  • Detection or SO 2 , H 2 S gas time-sharing detection by choosing to connect one monitoring area or time-sharing connecting the corresponding optical fiber photoacoustic sensing probes of multiple monitoring areas to realize gas detection in one monitoring area or multiple monitoring areas
  • Gas time-sharing detection application scenarios are not limited and meet the needs of multi-component gas detection of sulfur hexafluoride electrical equipment.
  • Both the excitation and detection light of the photoacoustic signal of the present invention are transmitted by optical fibers, and the entire sensing structure does not contain electrical components and has the ability to resist electromagnetic interference; at the same time, the long-distance transmission and low transmission loss characteristics of optical fibers can realize remote telemetry.
  • the detection method is suitable for gas detection in transformers, environmental monitoring, safety monitoring and other fields, and is a general monitoring system.
  • Fig. 1 is a structural schematic diagram of a distributed on-line monitoring system for sulfur hexafluoride decomposition products disclosed in Embodiment 1 of the present invention
  • Fig. 2 is a structural schematic diagram of an optical fiber photoacoustic sensing probe in a distributed on-line monitoring system for decomposition products of sulfur hexafluoride disclosed in Embodiment 1 of the present invention
  • Fig. 3 is the right side view of the optical fiber photoacoustic sensing probe in the distributed on-line monitoring system of sulfur hexafluoride decomposition products disclosed in Embodiment 1 of the present invention, that is, the front view of the cantilever beam structure;
  • Fig. 4 is a structural schematic diagram of a distributed on-line monitoring system for sulfur hexafluoride decomposition products disclosed in Embodiment 2 of the present invention
  • Fig. 5 is a schematic structural diagram of a distributed on-line monitoring system for decomposition products of sulfur hexafluoride disclosed in Example 3 of the present invention.
  • a distributed on-line monitoring system for sulfur hexafluoride decomposition products includes a first excitation light source device emitting ultraviolet light, a second excitation light source device emitting near-infrared light and a detection light source device, an optical fiber array 15 and Multiple groups of optical fiber photoacoustic sensing probes, the detection light source device emits broad-spectrum light for detecting photoacoustic signals, each group of optical fiber photoacoustic sensing probes is placed in a different area of SF 6 electrical equipment, each group of optical fiber photoacoustic sensing probes One end of the probe is respectively connected to the first excitation light source device through the optical fiber array 15, one end of each group of optical fiber photoacoustic sensing probe is respectively connected to the second excitation light source device through the optical fiber array 15, and the other end of each group of optical fiber photoacoustic sensing probe is Connect with the detection light source device respectively by optical fiber array 15;
  • the first excitation light source device that emits ultraviolet light is used for SO in
  • each group of optical fiber photoacoustic sensing probes is placed in different monitoring areas, and the gas detection in one monitoring area can be realized by selecting to connect one of the monitoring areas or connecting the corresponding optical fiber photoacoustic sensing probes in multiple monitoring areas in time Or the time-sharing detection of gas in multiple monitoring areas, and the entire system performs distributed detection.
  • the discharge of SF 6 electrical appliances produces H 2 S, SO 2 and other fault characteristic gases.
  • the first excitation light source device is selected to be connected to realize the separate detection of SO 2 gas.
  • the first excitation light source device includes a laser light source 5 and a collimating lens 17.
  • the detection light source device includes an optical fiber broadband light source 7 , an optical fiber circulator 8 , a second optical switch 9 , a spectrometer 10 and an industrial computer 11 .
  • the laser light source 5 emits an ultraviolet light beam of a specific wavelength to detect SO 2 , the beam is converged and split into each input end of the fiber array 15 through a collimating lens 17, and each output end of the fiber array 15 is respectively a One corresponding to one end of each group of optical fiber photoacoustic sensing probes.
  • the broadband light emitted by the optical fiber broadband light source 7 is incident on the second optical switch 9 through the optical fiber circulator 8, and the output channels of the second optical switch 9 are respectively one-to-one corresponding to the other end of each group of optical fiber photoacoustic sensing probes connection, the interference spectrum generated in each group of optical fiber photoacoustic sensing probes is returned from the optical fiber array 15 to the second optical switch 9 and output to the spectrometer 10 through the optical fiber circulator 8, and the industrial computer 11 collects the spectrum detected by the spectrometer 10 and performs signal processing. processing and display.
  • the high-speed spectrum demodulation method is used to demodulate the spectrum to obtain the dynamic cavity length of the interference cavity, and the amplitude of the photoacoustic signal is obtained by measuring the cavity length change of the interference cavity. According to the proportional relationship between the amplitude of the photoacoustic signal and the gas concentration The gas concentration is obtained and displayed.
  • optical fiber photoacoustic sensing probes There are three optical fiber photoacoustic sensing probes, which are the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13 and the third optical fiber photoacoustic sensing probe 14.
  • the optical fiber array 15 The number of output ends is greater than or equal to the number of optical fiber photoacoustic sensing probes, the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13 and the third optical fiber photoacoustic sensing probe 14 are respectively connected to the optical fiber array 15 an output terminal.
  • the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13 and the third optical fiber photoacoustic sensing probe 14 have the same structure, and all include an acoustic wave sensitive diaphragm 18 , an air chamber 19, an optical fiber end face 20, an optical fiber collimator 21 and a housing 22, the optical fiber end face 20 and the optical fiber collimator 21 are arranged in parallel in the housing 22, the optical fiber end face 20 and the optical fiber collimator 21 have the same shape and the optical fiber end face 20
  • One end of the fiber collimator 21 extends a fiber optic probe to the outside of the shell 22 and is connected to the detection light source device through the fiber array 15, and one end of the fiber collimator 21 extends out of the shell 22.
  • a fiber probe is connected to the excitation light source device through the fiber array 15;
  • the chamber 19 includes a photoacoustic tube and an air guide channel.
  • the photoacoustic tube is arranged horizontally and one end is connected to the other end of the optical fiber collimator 21.
  • the air guide channel is vertically arranged and the upper end communicates with the other end of the photoacoustic tube.
  • the air guide channel The lower end of the lower end is connected with the other end of the optical fiber end face 20, and the sound wave sensitive diaphragm 18 is arranged in parallel on the right side of the air guide channel, and the sound wave sensitive diaphragm 18 is used as the right side of the housing 22, and a cantilever beam structure 181, the cantilever beam structure 181 is a rectangular groove with a free end downward, the external gas to be measured diffuses into the gas chamber 19 through the slot of the cantilever beam structure 181 on the acoustic wave sensitive diaphragm 18, the gas chamber 19, the end face of the optical fiber 20 1.
  • the gap between the fiber optic collimator 21 and the housing 22 is filled with a solid body, wherein the volume of the air chamber 19 is 60 ⁇ L, the length of the photoacoustic cell is 10 mm, and the acoustic wave sensitive diaphragm 18 is a disc made of 304 stainless steel, and its diameter and thickness are respectively 10mm and 5 ⁇ m, the diaphragm is engraved with a cantilever beam structure 181 with a gap of 10 ⁇ m, the length and width of the cantilever beam are 1.6mm and 0.8mm respectively, the free end of the cantilever beam structure 181 and the fiber end face 20 constitute a Fabry-Perot interference cavity, static The cavity length is 200 ⁇ m.
  • the working distance of the fiber collimator 21 is 80 mm, which is 10 mm longer than the maximum length of the photoacoustic cell in the gas chamber 19 .
  • the photoacoustic excitation light source that is, ultraviolet light is incident into the gas chamber 19 through the fiber collimator 21 to excite the photoacoustic signal, and is detected by the acoustic wave sensitive diaphragm 18 installed on the outside of the gas chamber 19.
  • the free end of the cantilever beam structure 181 and the fiber end face 20 form a fiber Fabry-Perot interference cavity.
  • the photoacoustic signal causes the vibration of the cantilever beam structure 181 to cause the change of the length of the Fabry-Perot interference cavity. By detecting the cavity length of the interference cavity The change realizes the detection of the photoacoustic signal.
  • Both the excitation light and the detection light emitted by the detection light source device are transmitted through the optical fiber and time-divisionally incident into the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, and the third optical fiber photoacoustic sensing probe 14,
  • the entire sensing structure does not contain electrical components and has the ability to resist electromagnetic interference, which can be applied to the detection of large electrical equipment such as transformer oil; the long-distance transmission of optical fibers and the time-division multiplexing of multi-point probes realize distributed network monitoring and remote telemetry .
  • the working process of this embodiment is as follows: first, the laser light source 5 emits a laser beam of a specific wavelength, which is converged and collimated by the collimator lens 17, and the output laser beam is coupled into the optical fiber array 15, and transmitted to the first laser beam at different positions respectively.
  • the gas molecules to be measured in the fiber optic photoacoustic sensing probe absorb the laser energy and transition to a high energy level. The light energy releases energy through the non-radiative transition, causing the gas in the sensing probe to expand.
  • the sensing probe Since the laser is modulated by a periodic signal, the sensing probe The gas also expands with heat and contracts with cold periodically, forming sound pressure, and pushing the free end of the cantilever beam structure 181 of the sound wave sensitive diaphragm 18 in the sensing probe to vibrate periodically.
  • the wide-spectrum light emitted by the optical fiber wide-spectrum light source 7 is incident on the input end of the second optical switch 9 through the optical fiber circulator 8, and the output wide-spectrum light is respectively transmitted to the first optical fiber photoacoustic sensor through the other one of the optical fiber arrays 15.
  • Probe 12 the second optical fiber photoacoustic sensing probe 13, the third optical fiber photoacoustic sensing probe 14 and irradiate the free end of the cantilever beam structure 181 on the acoustic wave sensitive diaphragm 18 in the sensing probe;
  • the cantilever beam structure 181 of the acoustic wave sensitive diaphragm 18 in the probe forms a low-fineness optical fiber Fabry-Perot interference cavity, and the two surfaces of the interference cavity reflect broad-spectrum light to form an interference spectrum, which is transmitted to the second light through the optical fiber array 15.
  • the switch 9 is output to the spectrometer 10 through the optical fiber circulator 8; when the sound wave acts on the sound wave sensitive diaphragm 18, the Fabry-Perot interference cavity length changes, and the peak value of the interference spectrum detected by the spectrometer 10 moves; the interference spectrum is controlled by the industrial control
  • the industrial computer 11 collects, adopts the high-speed spectrum demodulation method to obtain the dynamic cavity length of the interference cavity, calculates the amplitude of the photoacoustic signal by measuring the cavity length change of the interference cavity, and the industrial computer 11 obtains the concentration of the gas to be measured according to the calibration coefficient and displays it.
  • the high-speed spectral demodulation method is a phase demodulation algorithm based on white light interference, through fast Fourier transform, the change of Fabry-Perot cavity length can be detected.
  • the laser light source 5 directly outputs a laser beam through the collimator lens 17, and the wavelength range of the light output is 300nm-5 ⁇ m, and the laser beam can be coupled to an optical fiber for long-distance transmission.
  • the second optical switch 9 is a fiber optic switch, and the number of optical switch channels is greater than or equal to the number of fiber optic photoacoustic sensing probes required for distributed detection.
  • the optical fiber wide-spectrum light source 7 is a near-infrared superluminescent light-emitting diode SLED or an amplified spontaneous emission ASE light source, and the spectral width is greater than 20nm.
  • the central wavelength is 1550 nm, and the spectral width is 60 nm.
  • the spectrometer 10 is a high-speed spectrometer, the spectral sampling rate and the number of pixels are respectively greater than 5KHz and 128, and the working wavelength range should cover the emission spectral range of the optical fiber spectral light source 7 .
  • the spectral sampling rate and the number of pixels of the spectrometer 10 are 5KHz and 128, and the working wavelength range is 1510nm-1590nm.
  • the difference between Embodiment 2 of the present invention and Embodiment 1 is that it provides another excitation light source device, that is, a second excitation light source device:
  • the second excitation light source device includes a laser drive circuit 16, a semiconductor laser 1 , erbium-doped fiber amplifier 4 and the first optical switch 6,
  • the laser drive circuit 16 drives the semiconductor laser 1 to make it emit near-infrared laser light into the erbium-doped fiber amplifier 4, the erbium-doped fiber amplifier 4 amplifies the optical power, and the amplified
  • the laser light enters the first optical switch 6, and each output channel of the first optical switch 6 is connected to the input port of the optical fiber array 15 in one-to-one correspondence, and each output port of the optical fiber array 15 is respectively in one-to-one correspondence with each group of optical fiber photoacoustic transmission channels.
  • the semiconductor laser 1 makes it emit near-infrared laser to detect H 2 S generated by electrical discharge of SF 6 .
  • the semiconductor laser 1 is a near-infrared DFB laser with a center wavelength of 1530 nm.
  • the laser drive circuit 16 drives the semiconductor laser 1, so that the semiconductor laser 1 emits near-infrared laser light respectively, and the laser light output by the semiconductor laser 1 is transmitted to the erbium-doped fiber amplifier 4 respectively, so as to realize the laser power amplification, the amplified laser light is transmitted to the input end of the first optical switch 6, and the output end of the first optical switch 6 is respectively connected to the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, The third optical fiber photoacoustic sensing probe 14, by switching the output end of the first optical switch 6, the laser light is transmitted to the first optical fiber photoacoustic sensing probe 12 and the second optical fiber photoacoustic sensing probe through one of the optical fiber arrays 15 respectively.
  • the third optical fiber photoacoustic sensing probe 14 The gas molecules to be measured in the probe absorb the laser energy and transition to a high energy level. The light energy releases energy through the non-radiative transition, causing the gas in the sensing probe to expand. Since the laser is modulated by a periodic signal, the gas in the sensing probe is also periodically heated. Expansion and contraction form sound pressure, which drives the free end of the cantilever beam structure 181 of the acoustic sensitive diaphragm 18 in the sensing probe to vibrate periodically.
  • the cantilever beam structure 181 of the acoustic wave sensitive diaphragm 18 is also formed by the optical fiber wide-spectrum light source 7, the optical fiber circulator 8, the second optical switch 9, the spectrometer 10 and the industrial computer 11 to form a low-fineness optical fiber Fabry-Perot
  • the two surfaces of the interference cavity reflect the interference spectrum formed by broad-spectrum light to detect and calculate the concentration of the gas to be measured and display it.
  • the detection and demodulation process of the interference spectrum is the same as that of Embodiment 1, and will not be repeated here.
  • the semiconductor laser 1 is a wavelength-tunable laser light source, packaged in a butterfly shape, coupled to an optical fiber to output laser light, and its central wavelength is made to correspond to the absorption wavelength of the gas to be measured by changing the driving bias current.
  • the first optical switch 6 and the second optical switch 9 are optical fiber optical switches of the same model, and the number of optical switch channels is equal to and greater than or equal to the number of optical fiber photoacoustic sensing probes required for distributed detection.
  • embodiment 3 adds the excitation light source device of embodiment 2 on the basis of embodiment 1, so that the whole system includes two groups of excitation light source devices with different wave bands at the same time, and can detect the H generated by the discharge of SF6 electrical appliances in time-sharing S and SO 2 .
  • Embodiment 3 The working process of Embodiment 3 is as follows: First, the laser light source 5 emits ultraviolet light of a specific wavelength, which is converged and collimated by the collimator lens 17, and the output laser beam is coupled into the optical fiber array 15, and is respectively transmitted to the first The optical fiber photoacoustic sensing probe 12 , the second optical fiber photoacoustic sensing probe 13 , and the third optical fiber photoacoustic sensing probe 14 .
  • the laser drive circuit 16 drives the semiconductor laser 1, so that the semiconductor laser 1 emits near-infrared light of a specific wavelength, and the near-infrared light is transmitted to the erbium-doped fiber amplifier 4 to amplify the laser power, and the amplified laser is transmitted to
  • the input end of the first optical switch 6 and the output end of the first optical switch 6 are respectively connected to the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, and the third optical fiber photoacoustic sensing probe 14, By switching the output end of the first optical switch 6, the laser light is respectively transmitted to the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, and the third optical fiber photoacoustic sensing probe through one of the optical fiber arrays 15.
  • the gas molecules to be measured in the probe absorb the laser energy and transition to a high energy level.
  • the light energy releases energy through the non-radiative transition, causing the gas in the sensing probe to expand.
  • the gas in the sensing probe is also periodically heated. Expansion and contraction form sound pressure, which drives the free end of the cantilever beam structure 181 of the acoustic sensitive diaphragm 18 in the sensing probe to vibrate periodically.
  • the wide-spectrum light emitted by the optical fiber broadband light source 7 is incident on the input end of the second optical switch 9 through the optical fiber circulator 8, and the output end of the second optical switch 9 is connected to the optical fiber photoacoustic sensing probe in the same order as the first optical switch 6, and The switching control of the output end is synchronized with the first optical switch 6, and the output broadband light is respectively transmitted to the first optical fiber photoacoustic sensing probe 12 and the second optical fiber photoacoustic sensing probe 13 through the other one of the multi-core optical fiber array 15 , the third optical fiber photoacoustic sensing probe 14 and irradiate the free end of the cantilever beam structure 181 on the acoustic wave sensitive diaphragm 18 in the sensing probe; the cantilever beam structure 181 of the optical fiber end face 20 and the acoustic wave sensitive diaphragm 18 in the sensing probe A low-fineness optical fiber Fabry-Perot interference cavity is formed, and the two surfaces of the interference cavity
  • the Spectrometer 10 when the sound wave acts on the sound wave sensitive diaphragm 18, the Fabry-Perot interference cavity length changes, and the peak of the interference spectrum detected by the spectrometer 10 moves; the interference spectrum is collected by the industrial computer 11, and high-speed spectrum demodulation is adopted
  • the dynamic cavity length of the interference cavity is obtained by the method, the amplitude of the photoacoustic signal is calculated by measuring the cavity length change of the interference cavity, and the industrial computer 11 obtains the concentration of the gas to be measured according to the calibration coefficient and displays it.

Abstract

Disclosed in the present invention are a distributed online monitoring system and method for a sulfur hexafluoride decomposition product. The system comprises a first excitation light source apparatus that emits ultraviolet light, a second excitation light source apparatus that emits near-infrared light, a detection light source apparatus, an optical fiber array, and a plurality of groups of optical fiber photoacoustic sensing probes; the detection light source apparatus emits broad spectrum light used for detecting a photoacoustic signal; each group of optical fiber photoacoustic sensing probes are arranged in different monitoring regions; one end of each group of optical fiber photoacoustic sensing probes is connected to the first excitation light source apparatus by means of the optical fiber array; and one end of each group of optical fiber photoacoustic sensing probes is connected to the second excitation light source apparatus by means of the optical fiber array, and the other end of each group of optical fiber photoacoustic sensing probes is connected to the detection light source apparatus by means of the optical fiber array. The present invention has the advantages that there are a plurality of excitation light sources, the application scenario is not limited, and the requirement for multi-component gas detection of a sulfur hexafluoride electrical device is satisfied.

Description

一种六氟化硫分解产物分布式在线监测***及方法A distributed on-line monitoring system and method for decomposition products of sulfur hexafluoride 技术领域technical field
本发明涉及光纤声波传感与光声光谱技术领域，更具体涉及一种六氟化硫分解产物分布式在线监测***及方法。The invention relates to the technical fields of optical fiber acoustic wave sensing and photoacoustic spectroscopy, and more specifically relates to a distributed on-line monitoring system and method for decomposition products of sulfur hexafluoride.
背景技术Background technique
光声光谱技术已成为检测痕量气体领域中的一种有效手段，光声光谱技术具有灵敏度高，无背景检测，响应速度快，不受电磁干扰等优点。其主要原理是基于气体分子的选择性吸收与朗伯-比尔定律，气体的光声效应主要可以由三个步骤解释：1.气体分子吸收特定波长的激发光，由基态跃迁到激发态；2.激发态的分子无辐射跃迁回到基态，释放热量，导致周围气体膨胀；3.当激发光以周期信号调制时，气体也呈周期型的热胀冷缩形成声波，被麦克风探测到，被探测到的光声信号和气体浓度呈正比。因此提高麦克风的灵敏度是提高光声光谱气体检测***灵敏度的有效手段。光纤声波传感是一种新的声波检测技术，其基本原理是利用光作为探测信号，通过声波敏感膜片感应外界温度、应变、压力等物理量的变化，并反应成光学参量的变化，实现对外界物理量的检测。这种方式具有抗电磁干扰，可远距离测量，分布式检测等优势。将光声光谱技术和光纤声波传感技术结合，实现对痕量气体的精准检测，并且不同于其他光声气体检测***，这种方式具有无源，微型的优势，非常适合在一些狭小区域，或者电磁干扰严重，如大型变电设备的特殊领域的气体检测。文献Chen Ke,Guo Min,Liu Shuai,et al.Fiber-optic photoacoustic sensor for remote monitoring of gas  micro-leakage[J].Optics express,2019,27(4):4648-4659报道了一种微型的光纤光声气体传感器，激光通过光纤传输到光声探头激发光声信号，同时光声信号由宽谱光检测获得气体浓度。但是，这种方式存在激发光源单一，应用场景固定的局限性，对于六氟化硫电气设备多组分气体检测的需求无法满足。Photoacoustic spectroscopy has become an effective method in the field of detection of trace gases. Photoacoustic spectroscopy has the advantages of high sensitivity, no background detection, fast response, and no electromagnetic interference. The main principle is based on the selective absorption of gas molecules and the Lambert-Beer law. The photoacoustic effect of gases can be explained by three steps: 1. Gas molecules absorb excitation light of a specific wavelength and transition from the ground state to the excited state; 2. . Molecules in the excited state transition back to the ground state without radiation, releasing heat and causing the surrounding gas to expand; 3. When the excitation light is modulated with a periodic signal, the gas also expands and contracts periodically to form sound waves, which are detected by the microphone and The detected photoacoustic signal is proportional to the gas concentration. Therefore, improving the sensitivity of the microphone is an effective means to improve the sensitivity of the photoacoustic spectroscopy gas detection system. Optical fiber acoustic wave sensing is a new acoustic wave detection technology. Its basic principle is to use light as a detection signal to sense changes in physical quantities such as external temperature, strain, and pressure through an acoustic wave sensitive diaphragm, and react to optical parameters. Detection of external physical quantities. This method has the advantages of anti-electromagnetic interference, long-distance measurement, and distributed detection. Combining photoacoustic spectroscopy technology and fiber optic acoustic wave sensing technology to achieve precise detection of trace gases, and different from other photoacoustic gas detection systems, this method has the advantages of passive and miniature, which is very suitable for some small areas, Or the electromagnetic interference is serious, such as gas detection in special fields of large-scale substation equipment. The literature Chen Ke, Guo Min, Liu Shuai, et al. Fiber-optic photoacoustic sensor for remote monitoring of gas micro-leakage[J]. Optics express, 2019,27(4):4648-4659 reported a miniature optical fiber In the photoacoustic gas sensor, the laser is transmitted to the photoacoustic probe through the optical fiber to excite the photoacoustic signal, and the photoacoustic signal is detected by the wide-spectrum light to obtain the gas concentration. However, this method has the limitations of a single excitation light source and fixed application scenarios, and cannot meet the requirements for multi-component gas detection of sulfur hexafluoride electrical equipment.
发明内容Contents of the invention
本发明所要解决的技术问题在于现有技术光纤光声传感方案存在激发光源单一，应用场景固定的局限性，对于六氟化硫电气设备多组分气体检测的需求无法满足的问题。The technical problem to be solved by the present invention is that the prior art optical fiber photoacoustic sensing scheme has the limitations of a single excitation light source and fixed application scenarios, and cannot meet the demand for multi-component gas detection of sulfur hexafluoride electrical equipment.
本发明通过以下技术手段实现解决上述技术问题的：一种六氟化硫分解产物分布式在线监测***，包括发射紫外光的第一激发光源装置、发射近红外光的第二激发光源装置以及探测光源装置、光纤阵列(15)以及多组光纤光声传感探头，所述探测光源装置发射用于探测光声信号的宽谱光，每组光纤光声传感探头置于不同的监测区域，每组光纤光声传感探头的一端通过光纤阵列(15)分别与第一激发光源装置连接，每组光纤光声传感探头的一端通过光纤阵列(15)分别与第二激发光源装置连接，每组光纤光声传感探头的另一端通过光纤阵列(15)分别与探测光源装置连接；发射紫外光的第一激发光源装置用于对SF 6电器设备中SO 2进行探测，发射近红外光的第二激发光源装置用于对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，每组光纤光声传感探头置于不同的监测区域，通过选择接通其中一个监测区域或者 分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测，整个***进行分布式检测。 The present invention solves the above-mentioned technical problems through the following technical means: a distributed on-line monitoring system for sulfur hexafluoride decomposition products, including a first excitation light source device emitting ultraviolet light, a second excitation light source device emitting near-infrared light, and a detection system. A light source device, an optical fiber array (15) and multiple groups of optical fiber photoacoustic sensing probes, the detection light source device emits broad-spectrum light for detecting photoacoustic signals, and each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area, One end of each group of optical fiber photoacoustic sensing probes is respectively connected to the first excitation light source device through an optical fiber array (15), and one end of each group of optical fiber photoacoustic sensing probes is respectively connected to the second excitation light source device through an optical fiber array (15), The other end of each group of optical fiber photoacoustic sensing probes is respectively connected to the detection light source device through the optical fiber array (15); the first excitation light source device emitting ultraviolet light is used to detect SO in SF 6 electrical equipment, and emits near-infrared light The second excitation light source device is used to detect H 2 S in SF 6 electrical equipment, by selectively connecting one group of excitation light source devices or by time-sharing two groups of excitation light source devices, the separate detection of SO 2 gas, H 2 Single detection of S gas or time-sharing detection of SO 2 and H 2 S gas. Each group of optical fiber photoacoustic sensing probes is placed in different monitoring areas. By selecting one of the monitoring areas or connecting multiple monitoring areas in time The fiber optic photoacoustic sensing probe realizes gas detection in one monitoring area or time-sharing detection of gas in multiple monitoring areas, and the whole system performs distributed detection.
本发明设置第一激发光源装置和第二激发光源装置，激光光源较多，通过发射紫外光的第一激发光源装置对SF 6电器设备中SO 2进行探测，通过发射近红外光的第二激发光源装置对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，通过选择接通一个监测区域或者分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测，应用场景不受局限且满足六氟化硫电气设备多组分气体检测的需求。 The present invention is provided with a first excitation light source device and a second excitation light source device, and there are many laser light sources, and the SO in SF6 electrical equipment is detected by the first excitation light source device emitting ultraviolet light, and by the second excitation light source device emitting near-infrared light The light source device detects H 2 S in SF 6 electrical equipment, and realizes separate detection of SO 2 gas, single detection of H 2 S gas or SO 2. Time-sharing detection of H 2 S gas, realize gas detection in one monitoring area or gas time-sharing in multiple monitoring areas by selecting to connect to one monitoring area or time-sharing connecting the corresponding optical fiber photoacoustic sensing probes of multiple monitoring areas Detection, application scenarios are not limited and meet the needs of multi-component gas detection of sulfur hexafluoride electrical equipment.
进一步地，所述第一激发光源装置包括激光光源(5)和准直透镜(17)，所述激光光源(5)发射特定波长的激光光束，经过准直透镜(17)将光束汇聚并分束耦合到光纤阵列(15)的各输入端中，光纤阵列(15)的各输出端分别一一对应的与各组光纤光声传感探头的一端连接。Further, the first excitation light source device includes a laser light source (5) and a collimator lens (17), the laser light source (5) emits a laser beam of a specific wavelength, and the beam is converged and split by the collimator lens (17). The bundles are coupled to each input end of the optical fiber array (15), and each output end of the optical fiber array (15) is connected to one end of each group of optical fiber photoacoustic sensing probes in one-to-one correspondence.
进一步地，所述第二激发光源装置包括激光驱动电路(16)、半导体激光器(1)、掺铒光纤放大器(4)及第一光开关(6)，所述激光驱动电路(16)驱动半导体激光器(1)使其发出特定波长的激光进入掺铒光纤放大器(4)，掺铒光纤放大器(4)对光功率进行放大，放大后的激光进入第一光开关(6)，第一光开关(6)的各输出通道分别一一对应的与光纤阵列(15)的输入端口连接，光纤阵列(15)的各输出端分别一一对应的与各组光纤光声传感探头的一端连接。Further, the second excitation light source device includes a laser drive circuit (16), a semiconductor laser (1), an erbium-doped fiber amplifier (4) and a first optical switch (6), and the laser drive circuit (16) drives the semiconductor The laser (1) makes it emit laser light of a specific wavelength to enter the erbium-doped fiber amplifier (4), and the erbium-doped fiber amplifier (4) amplifies the optical power, and the amplified laser light enters the first optical switch (6), and the first optical switch Each output channel of (6) is respectively one-to-one correspondingly connected with the input port of optical fiber array (15), and each output end of optical fiber array (15) is respectively connected with one end of each group of optical fiber photoacoustic sensing probes one-to-one correspondingly.
更进一步地，半导体激光器1为中心波长1530nm的近红外DFB激光 器。Furthermore, the semiconductor laser 1 is a near-infrared DFB laser with a central wavelength of 1530nm.
进一步地，所述探测光源装置包括光纤宽谱光源(7)、光纤环形器(8)、第二光开关(9)、光谱仪(10)及工控机(11)，所述光纤宽谱光源(7)发射的宽带光经光纤环形器(8)入射到第二光开关(9)，第二光开关(9)的各输出通道分别一一对应的与每组光纤光声传感探头的另一端连接，每组光纤光声传感探头内产生的干涉光谱再从光纤阵列(15)返回到第二光开关(9)经光纤环形器(8)输出到光谱仪(10)，工控机(11)采集光谱仪(10)探测到的光谱并进行信号处理和显示。Further, the detection light source device includes a fiber optic broadband light source (7), a fiber optic circulator (8), a second optical switch (9), a spectrometer (10) and an industrial computer (11), and the fiber optic broadband light source ( 7) The emitted broadband light enters the second optical switch (9) through the optical fiber circulator (8), and each output channel of the second optical switch (9) corresponds to the other channel of each group of optical fiber photoacoustic sensing probes one by one. One end is connected, and the interference spectrum generated in each group of optical fiber photoacoustic sensing probes is returned from the optical fiber array (15) to the second optical switch (9) and output to the spectrometer (10) through the optical fiber circulator (8), and the industrial computer (11 ) collect the spectrum detected by the spectrometer (10) and perform signal processing and display.
更进一步地，所述信号处理和显示包括：采用高速光谱解调法对光谱进行解调获得干涉腔的动态腔长，通过测量干涉腔的腔长变化获取光声信号的幅度，根据光声信号的幅度与气体浓度的比例关系获得气体浓度并显示出来。Furthermore, the signal processing and display includes: demodulating the spectrum by using high-speed spectrum demodulation method to obtain the dynamic cavity length of the interference cavity, and obtaining the amplitude of the photoacoustic signal by measuring the cavity length change of the interference cavity, and according to the photoacoustic signal The proportional relationship between the magnitude of the gas concentration and the gas concentration is obtained and displayed.
更进一步地，所述光纤宽谱光源(10)是近红外超辐射发光二极管SLED或者放大自发辐射ASE光源。Furthermore, the optical fiber broadband light source (10) is a near-infrared superluminescent light-emitting diode SLED or an amplified spontaneous emission ASE light source.
进一步地，所述光纤光声传感探头有3个，分别为第一光纤光声传感探头(12)、第二光纤光声传感探头(13)以及第三光纤光声传感探头(14)，所述光纤阵列(15)的输出端个数大于等于光纤光声传感探头的个数，第一光纤光声传感探头(12)、第二光纤光声传感探头(13)以及第三光纤光声传感探头(14)分别连接光纤阵列(15)一个输出端。Further, there are three optical fiber photoacoustic sensing probes, which are respectively the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe ( 14), the number of output ends of the optical fiber array (15) is greater than or equal to the number of optical fiber photoacoustic sensing probes, the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) And the third optical fiber photoacoustic sensing probe (14) is respectively connected to one output end of the optical fiber array (15).
更进一步地，所述第一光纤光声传感探头(12)、第二光纤光声传感探头(13)及第三光纤光声传感探头(14)结构相同，均包括声波敏感膜片(18)、气室(19)、光纤端面(20)、光纤准直器(21)及外壳(22)，所 述外壳(22)内平行布置光纤端面(20)和光纤准直器(21)，光纤端面(20)和光纤准直器(21)形状相同且光纤端面(20)的一端向外壳(22)外延伸出一个光纤探头通过光纤阵列(15)与探测光源装置连接，光纤准直器(21)的一端向外壳(22)外延伸出一个光纤探头通过光纤阵列(15)与激发光源装置连接；所述气室(19)包括光声管和导气通道，所述光声管水平设置且一端与光纤准直器(21)另一端衔接，导气通道竖直设置且上端与光声管的另一端相通，导气通道的下端与光纤端面(20)的另一端衔接，所述导气通道右侧平行设置声波敏感膜片(18)，声波敏感膜片(18)作为外壳(22)的右侧面，声波敏感膜片(18)上开设一个悬臂梁结构(181)，所述悬臂梁结构(181)为自由端向下的矩形槽，外部待测气体通过声波敏感膜片(18)上的悬臂梁结构(181)的槽缝扩散到气室(19)内。Furthermore, the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe (14) have the same structure, and all include acoustic wave sensitive diaphragms (18), air chamber (19), optical fiber end face (20), optical fiber collimator (21) and shell (22), in the described shell (22) parallel arrangement fiber end face (20) and optical fiber collimator (21 ), the fiber end face (20) and the fiber collimator (21) have the same shape and one end of the fiber end face (20) extends out of the shell (22) and a fiber probe is connected with the detection light source device through the fiber array (15), and the fiber collimator One end of the straight device (21) extends an optical fiber probe to the outer casing (22) and is connected with the exciting light source device through the optical fiber array (15); The tube is arranged horizontally and one end is connected with the other end of the optical fiber collimator (21), the air guide channel is arranged vertically and the upper end communicates with the other end of the photoacoustic tube, and the lower end of the air guide channel is connected with the other end of the optical fiber end face (20), The sound wave sensitive diaphragm (18) is arranged in parallel on the right side of the air guide passage, and the sound wave sensitive diaphragm (18) is used as the right side of the casing (22), and a cantilever beam structure (181) is set on the sound wave sensitive diaphragm (18). , the cantilever beam structure (181) is a rectangular groove with a free end downward, and the external gas to be measured diffuses into the gas chamber (19) through the slot of the cantilever beam structure (181) on the acoustic wave sensitive diaphragm (18).
本发明还提供一种六氟化硫分解产物分布式在线监测***的方法，发射紫外光的第一激发光源装置用于对SF 6电器设备中SO 2进行探测，发射近红外光的第二激发光源装置用于对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，每组光纤光声传感探头置于不同的监测区域，通过选择接通其中一个监测区域或者分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测，整个***进行分布式检测。 The present invention also provides a method for a distributed on-line monitoring system of sulfur hexafluoride decomposition products, the first excitation light source device emitting ultraviolet light is used to detect SO2 in SF6 electrical equipment, and the second excitation device emitting near-infrared light The light source device is used to detect H 2 S in SF 6 electrical equipment, and realize the separate detection of SO 2 gas and H 2 S gas by selectively connecting one group of excitation light source devices or two groups of excitation light source devices in time-sharing Or for time-sharing detection of SO 2 and H 2 S gas, each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area, and by selecting to connect one of the monitoring areas or connecting multiple monitoring areas corresponding to the optical fiber photoacoustic sensor The sensor probe realizes gas detection in one monitoring area or gas time-sharing detection in multiple monitoring areas, and the whole system performs distributed detection.
本发明的优点在于：The advantages of the present invention are:
(1)本发明设置第一激发光源装置和第二激发光源装置，激光光源较多，通过发射紫外光的第一激发光源装置对SF 6电器设备中SO 2进行探测， 通过发射近红外光的第二激发光源装置对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，通过选择接通一个监测区域或者分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测，应用场景不受局限且满足六氟化硫电气设备多组分气体检测的需求。 (1) the present invention is provided with the first excitation light source device and the second excitation light source device, and the laser light source is more, by the first excitation light source device of emitting ultraviolet light, SO in SF6 electrical equipment is detected, by emitting near-infrared light The second excitation light source device detects H 2 S in SF 6 electrical equipment, and realizes separate detection of SO 2 gas and separate detection of H 2 S gas by selectively connecting one group of excitation light source devices or connecting two groups of excitation light source devices in time-sharing. Detection or SO 2 , H 2 S gas time-sharing detection, by choosing to connect one monitoring area or time-sharing connecting the corresponding optical fiber photoacoustic sensing probes of multiple monitoring areas to realize gas detection in one monitoring area or multiple monitoring areas Gas time-sharing detection, application scenarios are not limited and meet the needs of multi-component gas detection of sulfur hexafluoride electrical equipment.
(2)本发明光声信号的激发和探测光均由光纤传输，整个传感结构不包含电学元件，具备抗电磁干扰能力；同时光纤的远距离传输和低传输损耗特性可实现远程遥测。检测方式适用于变压器、环境监测、安全监测等领域的气体检测，是通用的监测***。(2) Both the excitation and detection light of the photoacoustic signal of the present invention are transmitted by optical fibers, and the entire sensing structure does not contain electrical components and has the ability to resist electromagnetic interference; at the same time, the long-distance transmission and low transmission loss characteristics of optical fibers can realize remote telemetry. The detection method is suitable for gas detection in transformers, environmental monitoring, safety monitoring and other fields, and is a general monitoring system.
附图说明Description of drawings
图1为本发明实施例1所公开的一种六氟化硫分解产物分布式在线监测***的结构示意图；Fig. 1 is a structural schematic diagram of a distributed on-line monitoring system for sulfur hexafluoride decomposition products disclosed in Embodiment 1 of the present invention;
图2为本发明实施例1所公开的一种六氟化硫分解产物分布式在线监测***中光纤光声传感探头的结构示意图；Fig. 2 is a structural schematic diagram of an optical fiber photoacoustic sensing probe in a distributed on-line monitoring system for decomposition products of sulfur hexafluoride disclosed in Embodiment 1 of the present invention;
图3为本发明实施例1所公开的一种六氟化硫分解产物分布式在线监测***中光纤光声传感探头的右侧面视图也即悬臂梁结构的主视图；Fig. 3 is the right side view of the optical fiber photoacoustic sensing probe in the distributed on-line monitoring system of sulfur hexafluoride decomposition products disclosed in Embodiment 1 of the present invention, that is, the front view of the cantilever beam structure;
图4为本发明实施例2所公开的一种六氟化硫分解产物分布式在线监测***的结构示意图；Fig. 4 is a structural schematic diagram of a distributed on-line monitoring system for sulfur hexafluoride decomposition products disclosed in Embodiment 2 of the present invention;
图5为本发明实施例3所公开的一种六氟化硫分解产物分布式在线监测***的结构示意图。Fig. 5 is a schematic structural diagram of a distributed on-line monitoring system for decomposition products of sulfur hexafluoride disclosed in Example 3 of the present invention.
具体实施方式Detailed ways
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the present invention Examples, not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.
实施例1Example 1
如图1所示，一种六氟化硫分解产物分布式在线监测***，包括发射紫外光的第一激发光源装置、发射近红外光的第二激发光源装置以及探测光源装置、光纤阵列15以及多组光纤光声传感探头，所述探测光源装置发射宽谱光用于探测光声信号，每组光纤光声传感探头置于SF 6电器设备中不同区域，每组光纤光声传感探头的一端通过光纤阵列15分别与第一激发光源装置连接，每组光纤光声传感探头的一端通过光纤阵列15分别与第二激发光源装置连接，每组光纤光声传感探头的另一端通过光纤阵列15分别与探测光源装置连接；发射紫外光的第一激发光源装置用于对SF 6电器设备中SO 2进行探测，发射近红外光的第二激发光源装置用于对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，每组光纤光声传感探头置于不同的监测区域，通过选择接通其中一个监测区域或者分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测，整个***进行分布式检测。 As shown in Figure 1, a distributed on-line monitoring system for sulfur hexafluoride decomposition products includes a first excitation light source device emitting ultraviolet light, a second excitation light source device emitting near-infrared light and a detection light source device, an optical fiber array 15 and Multiple groups of optical fiber photoacoustic sensing probes, the detection light source device emits broad-spectrum light for detecting photoacoustic signals, each group of optical fiber photoacoustic sensing probes is placed in a different area of SF 6 electrical equipment, each group of optical fiber photoacoustic sensing probes One end of the probe is respectively connected to the first excitation light source device through the optical fiber array 15, one end of each group of optical fiber photoacoustic sensing probe is respectively connected to the second excitation light source device through the optical fiber array 15, and the other end of each group of optical fiber photoacoustic sensing probe is Connect with the detection light source device respectively by optical fiber array 15; The first excitation light source device that emits ultraviolet light is used for SO in SF 6 electrical equipment Detect, the second excitation light source device that emits near-infrared light is used for SF 6 electrical equipment To detect H 2 S in the medium, by choosing to connect one group of excitation light source devices or by time-sharing two groups of excitation light source devices, it is possible to realize SO 2 gas single detection, H 2 S gas single detection or SO 2 , H 2 S gas separation. Time detection, each group of optical fiber photoacoustic sensing probes is placed in different monitoring areas, and the gas detection in one monitoring area can be realized by selecting to connect one of the monitoring areas or connecting the corresponding optical fiber photoacoustic sensing probes in multiple monitoring areas in time Or the time-sharing detection of gas in multiple monitoring areas, and the entire system performs distributed detection.
SF 6电器放电产生H 2S、SO 2等故障特征气体，本实施例中，选择接通 第一激发光源装置，实现SO 2气体单独检测，第一激发光源装置包括激光光源5和准直透镜17，所述探测光源装置包括光纤宽谱光源7、光纤环形器8、第二光开关9、光谱仪10及工控机11。所述激光光源5发射特定波长的紫外光光束，对SO 2进行探测，经过准直透镜17将光束汇聚并分束耦合到光纤阵列15的各输入端中，光纤阵列15的各输出端分别一一对应的与各组光纤光声传感探头的一端连接。所述光纤宽谱光源7发射的宽带光经光纤环形器8入射到第二光开关9，第二光开关9的各输出通道分别一一对应的与每组光纤光声传感探头的另一端连接，每组光纤光声传感探头内产生的干涉光谱再从光纤阵列15返回到第二光开关9经光纤环形器8输出到光谱仪10，工控机11采集光谱仪10探测到的光谱并进行信号处理和显示。本实施例中采用高速光谱解调法对光谱进行解调获得干涉腔的动态腔长，通过测量干涉腔的腔长变化获取光声信号的幅度，根据光声信号的幅度与气体浓度的比例关系获得气体浓度并显示出来。 The discharge of SF 6 electrical appliances produces H 2 S, SO 2 and other fault characteristic gases. In this embodiment, the first excitation light source device is selected to be connected to realize the separate detection of SO 2 gas. The first excitation light source device includes a laser light source 5 and a collimating lens 17. The detection light source device includes an optical fiber broadband light source 7 , an optical fiber circulator 8 , a second optical switch 9 , a spectrometer 10 and an industrial computer 11 . The laser light source 5 emits an ultraviolet light beam of a specific wavelength to detect SO 2 , the beam is converged and split into each input end of the fiber array 15 through a collimating lens 17, and each output end of the fiber array 15 is respectively a One corresponding to one end of each group of optical fiber photoacoustic sensing probes. The broadband light emitted by the optical fiber broadband light source 7 is incident on the second optical switch 9 through the optical fiber circulator 8, and the output channels of the second optical switch 9 are respectively one-to-one corresponding to the other end of each group of optical fiber photoacoustic sensing probes connection, the interference spectrum generated in each group of optical fiber photoacoustic sensing probes is returned from the optical fiber array 15 to the second optical switch 9 and output to the spectrometer 10 through the optical fiber circulator 8, and the industrial computer 11 collects the spectrum detected by the spectrometer 10 and performs signal processing. processing and display. In this embodiment, the high-speed spectrum demodulation method is used to demodulate the spectrum to obtain the dynamic cavity length of the interference cavity, and the amplitude of the photoacoustic signal is obtained by measuring the cavity length change of the interference cavity. According to the proportional relationship between the amplitude of the photoacoustic signal and the gas concentration The gas concentration is obtained and displayed.
所述光纤光声传感探头有3个，分别为第一光纤光声传感探头12、第二光纤光声传感探头13以及第三光纤光声传感探头14，所述光纤阵列15的输出端个数大于等于光纤光声传感探头的个数，第一光纤光声传感探头12、第二光纤光声传感探头13以及第三光纤光声传感探头14分别连接光纤阵列15一个输出端。There are three optical fiber photoacoustic sensing probes, which are the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13 and the third optical fiber photoacoustic sensing probe 14. The optical fiber array 15 The number of output ends is greater than or equal to the number of optical fiber photoacoustic sensing probes, the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13 and the third optical fiber photoacoustic sensing probe 14 are respectively connected to the optical fiber array 15 an output terminal.
如图2和图3所示，所述第一光纤光声传感探头12、第二光纤光声传感探头13及第三光纤光声传感探头14结构相同，均包括声波敏感膜片18、气室19、光纤端面20、光纤准直器21及外壳22，所述外壳22内平行布置光纤端面20和光纤准直器21，光纤端面20和光纤准直器21形状相同且光 纤端面20的一端向外壳22外延伸出一个光纤探头通过光纤阵列15与探测光源装置连接，光纤准直器21的一端向外壳22外延伸出一个光纤探头通过光纤阵列15与激发光源装置连接；所述气室19包括光声管和导气通道，所述光声管水平设置且一端与光纤准直器21另一端衔接，导气通道竖直设置且上端与光声管的另一端相通，导气通道的下端与光纤端面20的另一端衔接，所述导气通道右侧平行设置声波敏感膜片18，声波敏感膜片18作为外壳22的右侧面，声波敏感膜片18上开设一个悬臂梁结构181，所述悬臂梁结构181为自由端向下的矩形槽，外部待测气体通过声波敏感膜片18上的悬臂梁结构181的槽缝扩散到气室19内，气室19、光纤端面20、光纤准直器21与外壳22之间的间隙采用实体填充，其中，气室19体积60μL，光声池长10mm，声波敏感膜片18是材料为304不锈钢的圆片，直径和厚度分别为10mm和5μm，膜片上刻有缝隙为10μm的悬臂梁结构181，悬臂梁长宽分别为1.6mm和0.8mm，悬臂梁结构181的自由端和光纤端面20构成法布里-珀罗干涉腔，静态腔长为200μm。光纤准直器21工作距离为80mm，大于气室19内光声池最大长度10mm。As shown in Figures 2 and 3, the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13 and the third optical fiber photoacoustic sensing probe 14 have the same structure, and all include an acoustic wave sensitive diaphragm 18 , an air chamber 19, an optical fiber end face 20, an optical fiber collimator 21 and a housing 22, the optical fiber end face 20 and the optical fiber collimator 21 are arranged in parallel in the housing 22, the optical fiber end face 20 and the optical fiber collimator 21 have the same shape and the optical fiber end face 20 One end of the fiber collimator 21 extends a fiber optic probe to the outside of the shell 22 and is connected to the detection light source device through the fiber array 15, and one end of the fiber collimator 21 extends out of the shell 22. A fiber probe is connected to the excitation light source device through the fiber array 15; The chamber 19 includes a photoacoustic tube and an air guide channel. The photoacoustic tube is arranged horizontally and one end is connected to the other end of the optical fiber collimator 21. The air guide channel is vertically arranged and the upper end communicates with the other end of the photoacoustic tube. The air guide channel The lower end of the lower end is connected with the other end of the optical fiber end face 20, and the sound wave sensitive diaphragm 18 is arranged in parallel on the right side of the air guide channel, and the sound wave sensitive diaphragm 18 is used as the right side of the housing 22, and a cantilever beam structure 181, the cantilever beam structure 181 is a rectangular groove with a free end downward, the external gas to be measured diffuses into the gas chamber 19 through the slot of the cantilever beam structure 181 on the acoustic wave sensitive diaphragm 18, the gas chamber 19, the end face of the optical fiber 20 1. The gap between the fiber optic collimator 21 and the housing 22 is filled with a solid body, wherein the volume of the air chamber 19 is 60 μL, the length of the photoacoustic cell is 10 mm, and the acoustic wave sensitive diaphragm 18 is a disc made of 304 stainless steel, and its diameter and thickness are respectively 10mm and 5μm, the diaphragm is engraved with a cantilever beam structure 181 with a gap of 10μm, the length and width of the cantilever beam are 1.6mm and 0.8mm respectively, the free end of the cantilever beam structure 181 and the fiber end face 20 constitute a Fabry-Perot interference cavity, static The cavity length is 200 μm. The working distance of the fiber collimator 21 is 80 mm, which is 10 mm longer than the maximum length of the photoacoustic cell in the gas chamber 19 .
所述光声激发光源也即紫外光经光纤准直器21入射到气室19内以激发光声信号，并被安装在气室19外侧的声波敏感膜片18检测，声波敏感膜片18的悬臂梁结构181的自由端与光纤端面20构成光纤法布里-珀罗干涉腔，光声信号使悬臂梁结构181振动引起法布里-珀罗干涉腔长变化，通过检测干涉腔的腔长变化实现对光声信号的检测。激发光和探测光源装置发射的探测光均通过光纤传输并分时入射到第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14中，整个传感结构不包 含电学元件，具备抗电磁干扰能力，可适用于变压器油等大型电器设备检测的情况；光纤的远距离传输和多点探头时分复用，实现分布式布网监测和远程遥测。The photoacoustic excitation light source, that is, ultraviolet light is incident into the gas chamber 19 through the fiber collimator 21 to excite the photoacoustic signal, and is detected by the acoustic wave sensitive diaphragm 18 installed on the outside of the gas chamber 19. The free end of the cantilever beam structure 181 and the fiber end face 20 form a fiber Fabry-Perot interference cavity. The photoacoustic signal causes the vibration of the cantilever beam structure 181 to cause the change of the length of the Fabry-Perot interference cavity. By detecting the cavity length of the interference cavity The change realizes the detection of the photoacoustic signal. Both the excitation light and the detection light emitted by the detection light source device are transmitted through the optical fiber and time-divisionally incident into the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, and the third optical fiber photoacoustic sensing probe 14, The entire sensing structure does not contain electrical components and has the ability to resist electromagnetic interference, which can be applied to the detection of large electrical equipment such as transformer oil; the long-distance transmission of optical fibers and the time-division multiplexing of multi-point probes realize distributed network monitoring and remote telemetry .
本实施例的工作过程为：首先，激光光源5发射特定波长的激光光束，经准直透镜17进行汇聚准直，输出的激光光束被耦合到光纤阵列15中，分别传输到不同位置的第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14。光纤光声传感探头中的待测气体分子吸收激光能量并跃迁到高能级，光能通过无辐射跃迁释放能量，引起传感探头内气体膨胀，由于激光被周期信号调制，因此传感探头内气体也周期性热胀冷缩，形成声压，推动传感探头内声波敏感膜片18的悬臂梁结构181的自由端周期性振动。The working process of this embodiment is as follows: first, the laser light source 5 emits a laser beam of a specific wavelength, which is converged and collimated by the collimator lens 17, and the output laser beam is coupled into the optical fiber array 15, and transmitted to the first laser beam at different positions respectively. The optical fiber photoacoustic sensing probe 12 , the second optical fiber photoacoustic sensing probe 13 , and the third optical fiber photoacoustic sensing probe 14 . The gas molecules to be measured in the fiber optic photoacoustic sensing probe absorb the laser energy and transition to a high energy level. The light energy releases energy through the non-radiative transition, causing the gas in the sensing probe to expand. Since the laser is modulated by a periodic signal, the sensing probe The gas also expands with heat and contracts with cold periodically, forming sound pressure, and pushing the free end of the cantilever beam structure 181 of the sound wave sensitive diaphragm 18 in the sensing probe to vibrate periodically.
然后，光纤宽谱光源7发射宽谱光经光纤环形器8入射到第二光开关9输入端，输出的宽谱光经光纤阵列15中的另一根分别传输到第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14并照射到传感探头内声波敏感膜片18上的悬臂梁结构181的自由端；光纤端面20与传感探头内声波敏感膜片18的悬臂梁结构181形成低细度的光纤法布里-珀罗干涉腔，干涉腔的两个面反射宽谱光形成干涉光谱，经光纤阵列15传输到第二光开关9并通过光纤环形器8输出到光谱仪10；当声波作用在声波敏感膜片18时，引起法布里-珀罗干涉腔长变化，光谱仪10检测的干涉光谱峰值发生移动；干涉光谱由工控机11进行采集，采用高速光谱解调法获得干涉腔的动态腔长，通过测量干涉腔的腔长变化计算光声信号的幅度，工控机11根据标定系数得到待测气体的浓度并显示出来。所述高速光 谱解调法是一种基于白光干涉的相位解调算法，通过快速傅里叶变换，可检测法布里-珀罗腔长变化。Then, the wide-spectrum light emitted by the optical fiber wide-spectrum light source 7 is incident on the input end of the second optical switch 9 through the optical fiber circulator 8, and the output wide-spectrum light is respectively transmitted to the first optical fiber photoacoustic sensor through the other one of the optical fiber arrays 15. Probe 12, the second optical fiber photoacoustic sensing probe 13, the third optical fiber photoacoustic sensing probe 14 and irradiate the free end of the cantilever beam structure 181 on the acoustic wave sensitive diaphragm 18 in the sensing probe; The cantilever beam structure 181 of the acoustic wave sensitive diaphragm 18 in the probe forms a low-fineness optical fiber Fabry-Perot interference cavity, and the two surfaces of the interference cavity reflect broad-spectrum light to form an interference spectrum, which is transmitted to the second light through the optical fiber array 15. The switch 9 is output to the spectrometer 10 through the optical fiber circulator 8; when the sound wave acts on the sound wave sensitive diaphragm 18, the Fabry-Perot interference cavity length changes, and the peak value of the interference spectrum detected by the spectrometer 10 moves; the interference spectrum is controlled by the industrial control The industrial computer 11 collects, adopts the high-speed spectrum demodulation method to obtain the dynamic cavity length of the interference cavity, calculates the amplitude of the photoacoustic signal by measuring the cavity length change of the interference cavity, and the industrial computer 11 obtains the concentration of the gas to be measured according to the calibration coefficient and displays it. The high-speed spectral demodulation method is a phase demodulation algorithm based on white light interference, through fast Fourier transform, the change of Fabry-Perot cavity length can be detected.
所述激光光源5经准直透镜17直接输出激光光束，出光波长范围为300nm-5μm，激光光束可耦合到光纤中远距离传输。The laser light source 5 directly outputs a laser beam through the collimator lens 17, and the wavelength range of the light output is 300nm-5μm, and the laser beam can be coupled to an optical fiber for long-distance transmission.
所述第二光开关9为光纤光开关，光开关通道数大于等于分布式检测所需光纤光声传感探头数。The second optical switch 9 is a fiber optic switch, and the number of optical switch channels is greater than or equal to the number of fiber optic photoacoustic sensing probes required for distributed detection.
所述光纤宽谱光源7是近红外超辐射发光二极管SLED或者放大自发辐射ASE光源，谱宽大于20nm。本实施例中其中心波长1550nm，谱宽60nm。The optical fiber wide-spectrum light source 7 is a near-infrared superluminescent light-emitting diode SLED or an amplified spontaneous emission ASE light source, and the spectral width is greater than 20nm. In this embodiment, the central wavelength is 1550 nm, and the spectral width is 60 nm.
所述光谱仪10为高速光谱仪，光谱采样速率和像素数分别大于5KHz和128，工作的波长范围应覆盖光纤光谱光源7的发射光谱范围。本实施例中，光谱仪10的光谱采样速率和像素数为5KHz和128，工作的波长范围为1510nm-1590nm。The spectrometer 10 is a high-speed spectrometer, the spectral sampling rate and the number of pixels are respectively greater than 5KHz and 128, and the working wavelength range should cover the emission spectral range of the optical fiber spectral light source 7 . In this embodiment, the spectral sampling rate and the number of pixels of the spectrometer 10 are 5KHz and 128, and the working wavelength range is 1510nm-1590nm.
实施例2Example 2
如图4所示，本发明实施例2相比实施例1的区别在于提供另外一种激发光源装置也即第二激发光源装置：所述第二激发光源装置包括激光驱动电路16、半导体激光器1、掺铒光纤放大器4及第一光开关6，所述激光驱动电路16驱动半导体激光器1使其发出近红外激光进入掺铒光纤放大器4，掺铒光纤放大器4对光功率进行放大，放大后的激光进入第一光开关6，第一光开关6的各输出通道分别一一对应的与光纤阵列15的输入端口连接，光纤阵列15的各输出端分别一一对应的与各组光纤光声传感探头的一端连 接。半导体激光器1使其发出近红外激光能够检测SF 6电器放电产生的H 2S。半导体激光器1为中心波长1530nm的近红外DFB激光器。 As shown in Figure 4, the difference between Embodiment 2 of the present invention and Embodiment 1 is that it provides another excitation light source device, that is, a second excitation light source device: the second excitation light source device includes a laser drive circuit 16, a semiconductor laser 1 , erbium-doped fiber amplifier 4 and the first optical switch 6, the laser drive circuit 16 drives the semiconductor laser 1 to make it emit near-infrared laser light into the erbium-doped fiber amplifier 4, the erbium-doped fiber amplifier 4 amplifies the optical power, and the amplified The laser light enters the first optical switch 6, and each output channel of the first optical switch 6 is connected to the input port of the optical fiber array 15 in one-to-one correspondence, and each output port of the optical fiber array 15 is respectively in one-to-one correspondence with each group of optical fiber photoacoustic transmission channels. Connect one end of the sensor probe. The semiconductor laser 1 makes it emit near-infrared laser to detect H 2 S generated by electrical discharge of SF 6 . The semiconductor laser 1 is a near-infrared DFB laser with a center wavelength of 1530 nm.
本实施例的工作过程为：首先，激光驱动电路16对半导体激光器1进行驱动，使半导体激光器1分别发出近红外激光，半导体激光器1输出的激光分别传输到掺铒光纤放大器4中，实现对激光功率的放大，放大后的激光传输到第一光开关6的输入端，第一光开关6的输出端分别连接了第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14，通过切换第一光开关6输出端使激光经光纤阵列15中的一根分别传输到第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14。探头中的待测气体分子吸收激光能量并跃迁到高能级，光能通过无辐射跃迁释放能量，引起传感探头内气体膨胀，由于激光被周期信号调制，因此传感探头内气体也周期性热胀冷缩，形成声压，推动传感探头内声波敏感膜片18的悬臂梁结构181的自由端周期性振动。The working process of this embodiment is as follows: firstly, the laser drive circuit 16 drives the semiconductor laser 1, so that the semiconductor laser 1 emits near-infrared laser light respectively, and the laser light output by the semiconductor laser 1 is transmitted to the erbium-doped fiber amplifier 4 respectively, so as to realize the laser power amplification, the amplified laser light is transmitted to the input end of the first optical switch 6, and the output end of the first optical switch 6 is respectively connected to the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, The third optical fiber photoacoustic sensing probe 14, by switching the output end of the first optical switch 6, the laser light is transmitted to the first optical fiber photoacoustic sensing probe 12 and the second optical fiber photoacoustic sensing probe through one of the optical fiber arrays 15 respectively. 13. The third optical fiber photoacoustic sensing probe 14. The gas molecules to be measured in the probe absorb the laser energy and transition to a high energy level. The light energy releases energy through the non-radiative transition, causing the gas in the sensing probe to expand. Since the laser is modulated by a periodic signal, the gas in the sensing probe is also periodically heated. Expansion and contraction form sound pressure, which drives the free end of the cantilever beam structure 181 of the acoustic sensitive diaphragm 18 in the sensing probe to vibrate periodically.
最后，同样通过光纤宽谱光源7、光纤环形器8、第二光开关9、光谱仪10及工控机11对声波敏感膜片18的悬臂梁结构181形成低细度的光纤法布里-珀罗干涉腔的两个面反射宽谱光形成的干涉光谱进行探测和计算得到待测气体的浓度并显示出来，对干涉谱的探测和解调过程与实施例1相同，在此不做赘述。Finally, the cantilever beam structure 181 of the acoustic wave sensitive diaphragm 18 is also formed by the optical fiber wide-spectrum light source 7, the optical fiber circulator 8, the second optical switch 9, the spectrometer 10 and the industrial computer 11 to form a low-fineness optical fiber Fabry-Perot The two surfaces of the interference cavity reflect the interference spectrum formed by broad-spectrum light to detect and calculate the concentration of the gas to be measured and display it. The detection and demodulation process of the interference spectrum is the same as that of Embodiment 1, and will not be repeated here.
所述半导体激光器1为波长可调谐激光光源，蝶形封装，耦合光纤输出激光，其中心波长通过改变驱动偏置电流使其对应到待测气体的吸收波长处。The semiconductor laser 1 is a wavelength-tunable laser light source, packaged in a butterfly shape, coupled to an optical fiber to output laser light, and its central wavelength is made to correspond to the absorption wavelength of the gas to be measured by changing the driving bias current.
所述第一光开关6与第二光开关9为相同型号光纤光开关，光开关通道数相等，且大于等于分布式检测所需光纤光声传感探头数。The first optical switch 6 and the second optical switch 9 are optical fiber optical switches of the same model, and the number of optical switch channels is equal to and greater than or equal to the number of optical fiber photoacoustic sensing probes required for distributed detection.
实施例3Example 3
如图5所示，实施例3是实施例1的基础上添加实施例2的激发光源装置，使得整个***同时包括2组不同波段的激发光源装置，能够分时检测SF 6电器放电产生H 2S和SO 2。 As shown in Figure 5, embodiment 3 adds the excitation light source device of embodiment 2 on the basis of embodiment 1, so that the whole system includes two groups of excitation light source devices with different wave bands at the same time, and can detect the H generated by the discharge of SF6 electrical appliances in time-sharing S and SO 2 .
实施例3的工作过程为：首先，激光光源5发射特定波长的紫外光，经准直透镜17进行汇聚准直，输出的激光光束被耦合到光纤阵列15中，分别传输到不同位置的第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14。然后，激光驱动电路16对半导体激光器1进行驱动，使半导体激光器1发出特定波长的近红外光，近红外光传输到掺铒光纤放大器4中，实现对激光功率的放大，放大后的激光传输到第一光开关6的输入端，第一光开关6的输出端分别连接了第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14，通过切换第一光开关6输出端使激光经光纤阵列15中的一根分别传输到第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14。探头中的待测气体分子吸收激光能量并跃迁到高能级，光能通过无辐射跃迁释放能量，引起传感探头内气体膨胀，由于激光被周期信号调制，因此传感探头内气体也周期性热胀冷缩，形成声压，推动传感探头内声波敏感膜片18的悬臂梁结构181的自由端周期性振动。The working process of Embodiment 3 is as follows: First, the laser light source 5 emits ultraviolet light of a specific wavelength, which is converged and collimated by the collimator lens 17, and the output laser beam is coupled into the optical fiber array 15, and is respectively transmitted to the first The optical fiber photoacoustic sensing probe 12 , the second optical fiber photoacoustic sensing probe 13 , and the third optical fiber photoacoustic sensing probe 14 . Then, the laser drive circuit 16 drives the semiconductor laser 1, so that the semiconductor laser 1 emits near-infrared light of a specific wavelength, and the near-infrared light is transmitted to the erbium-doped fiber amplifier 4 to amplify the laser power, and the amplified laser is transmitted to The input end of the first optical switch 6 and the output end of the first optical switch 6 are respectively connected to the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, and the third optical fiber photoacoustic sensing probe 14, By switching the output end of the first optical switch 6, the laser light is respectively transmitted to the first optical fiber photoacoustic sensing probe 12, the second optical fiber photoacoustic sensing probe 13, and the third optical fiber photoacoustic sensing probe through one of the optical fiber arrays 15. 14. The gas molecules to be measured in the probe absorb the laser energy and transition to a high energy level. The light energy releases energy through the non-radiative transition, causing the gas in the sensing probe to expand. Since the laser is modulated by a periodic signal, the gas in the sensing probe is also periodically heated. Expansion and contraction form sound pressure, which drives the free end of the cantilever beam structure 181 of the acoustic sensitive diaphragm 18 in the sensing probe to vibrate periodically.
最后，光纤宽谱光源7发射宽谱光经光纤环形器8入射到第二光开关9 输入端，第二光开关9输出端连接光纤光声传感探头顺序和第一光开关6一致，并且输出端切换控制和第一光开关6同步，输出的宽谱光经多芯光纤阵列15中的另一根分别传输到第一光纤光声传感探头12、第二光纤光声传感探头13、第三光纤光声传感探头14并照射到传感探头内声波敏感膜片18上的悬臂梁结构181的自由端；光纤端面20与传感探头内声波敏感膜片18的悬臂梁结构181形成低细度的光纤法布里-珀罗干涉腔，干涉腔的两个面反射宽谱光形成干涉光谱，经多芯光纤阵列15传输到第二光开关9并通过光纤环形器8输出到光谱仪10；当声波作用在声波敏感膜片18时，引起法布里-珀罗干涉腔长变化，光谱仪10检测的干涉光谱峰值发生移动；干涉光谱由工控机11进行采集，采用高速光谱解调法获得干涉腔的动态腔长，通过测量干涉腔的腔长变化计算光声信号的幅度，工控机11根据标定系数得到待测气体的浓度并显示出来。Finally, the wide-spectrum light emitted by the optical fiber broadband light source 7 is incident on the input end of the second optical switch 9 through the optical fiber circulator 8, and the output end of the second optical switch 9 is connected to the optical fiber photoacoustic sensing probe in the same order as the first optical switch 6, and The switching control of the output end is synchronized with the first optical switch 6, and the output broadband light is respectively transmitted to the first optical fiber photoacoustic sensing probe 12 and the second optical fiber photoacoustic sensing probe 13 through the other one of the multi-core optical fiber array 15 , the third optical fiber photoacoustic sensing probe 14 and irradiate the free end of the cantilever beam structure 181 on the acoustic wave sensitive diaphragm 18 in the sensing probe; the cantilever beam structure 181 of the optical fiber end face 20 and the acoustic wave sensitive diaphragm 18 in the sensing probe A low-fineness optical fiber Fabry-Perot interference cavity is formed, and the two surfaces of the interference cavity reflect broad-spectrum light to form an interference spectrum, which is transmitted to the second optical switch 9 through the multi-core optical fiber array 15 and output to the second optical switch 9 through the optical fiber circulator 8. Spectrometer 10; when the sound wave acts on the sound wave sensitive diaphragm 18, the Fabry-Perot interference cavity length changes, and the peak of the interference spectrum detected by the spectrometer 10 moves; the interference spectrum is collected by the industrial computer 11, and high-speed spectrum demodulation is adopted The dynamic cavity length of the interference cavity is obtained by the method, the amplitude of the photoacoustic signal is calculated by measuring the cavity length change of the interference cavity, and the industrial computer 11 obtains the concentration of the gas to be measured according to the calibration coefficient and displays it.
以上实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的精神和范围。The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications are made to the recorded technical solutions, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

  1. 一种六氟化硫分解产物分布式在线监测***，其特征在于，包括发射紫外光的第一激发光源装置、发射近红外光的第二激发光源装置以及探测光源装置、光纤阵列(15)以及多组光纤光声传感探头，所述探测光源装置发射用于探测光声信号的宽谱光，每组光纤光声传感探头置于不同的监测区域，每组光纤光声传感探头的一端通过光纤阵列(15)分别与第一激发光源装置连接，每组光纤光声传感探头的一端通过光纤阵列(15)分别与第二激发光源装置连接，每组光纤光声传感探头的另一端通过光纤阵列(15)分别与探测光源装置连接；发射紫外光的第一激发光源装置用于对SF 6电器设备中SO 2进行探测，发射近红外光的第二激发光源装置用于对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，每组光纤光声传感探头置于不同的监测区域，通过选择接通其中一个监测区域或者分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测，整个***进行分布式检测。 A distributed on-line monitoring system for decomposition products of sulfur hexafluoride, characterized in that it includes a first excitation light source device emitting ultraviolet light, a second excitation light source device emitting near-infrared light, a detection light source device, an optical fiber array (15) and Multiple groups of optical fiber photoacoustic sensing probes, the detection light source device emits broad-spectrum light for detecting photoacoustic signals, each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area, each group of optical fiber photoacoustic sensing probes One end is respectively connected with the first excitation light source device through the optical fiber array (15), and one end of each group of optical fiber photoacoustic sensing probes is respectively connected with the second excitation light source device through the optical fiber array (15), and each group of optical fiber photoacoustic sensing probes The other end is respectively connected with the detection light source device by the optical fiber array (15); the first excitation light source device for emitting ultraviolet light is used to detect SO in the SF6 electrical equipment, and the second excitation light source device for emitting near-infrared light is used for detecting For H 2 S detection in SF 6 electrical equipment, by choosing to connect one group of excitation light source devices or connecting two groups of excitation light source devices in a time-sharing manner, separate detection of SO 2 gas, single detection of H 2 S gas or SO 2 , H 2 S gas time-sharing detection, each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area, and a monitoring is realized by selecting to connect one of the monitoring areas or connecting multiple optical fiber photoacoustic sensing probes corresponding to multiple monitoring areas in time Regional gas detection or gas time-sharing detection in multiple monitoring areas, the entire system performs distributed detection.
  2. 根据权利要求1所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述第一激发光源装置包括激光光源(5)和准直透镜(17)，所述激光光源(5)发射特定波长的激光光束，经过准直透镜(17)将光束汇聚并分束耦合到光纤阵列(15)的各输入端中，光纤阵列(15)的各输出端分别一一对应的与各组光纤光声传感探头的一端连接。A distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 1, wherein the first excitation light source device includes a laser light source (5) and a collimating lens (17), and the laser light source (5) emit a laser beam of a specific wavelength, through the collimating lens (17) the beam is converged and split into each input end of the optical fiber array (15), and each output end of the optical fiber array (15) corresponds to each other respectively Connect with one end of each group of optical fiber photoacoustic sensing probes.
  3. 根据权利要求2所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述激光光源(5)的出光波长范围为300nm-5μm。The distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 2, characterized in that the laser light source (5) has a wavelength range of 300nm-5μm.
  4. 根据权利要求1所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述第二激发光源装置包括激光驱动电路(16)、半导体激光器(1)、掺铒光纤放大器(4)及第一光开关(6)，所述激光驱动电路(16)驱动半导体激光器(1)使其发出特定波长的激光进入掺铒光纤放大器(4)，掺铒光纤放大器(4)对光功率进行放大，放大后的激光进入第一光开关(6)，第一光开关(6)的各输出通道分别一一对应的与光纤阵列(15)的输入端口连接，光纤阵列(15)的各输出端分别一一对应的与各组光纤光声传感探头的一端连接。A distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 1, wherein the second excitation light source device includes a laser drive circuit (16), a semiconductor laser (1), and an erbium-doped fiber amplifier (4) and the first optical switch (6), the laser driver circuit (16) drives the semiconductor laser (1) to make it send the laser light of specific wavelength to enter the erbium-doped fiber amplifier (4), and the erbium-doped fiber amplifier (4) is to The optical power is amplified, and the amplified laser light enters the first optical switch (6), and each output channel of the first optical switch (6) is connected to the input port of the optical fiber array (15) in one-to-one correspondence, and the optical fiber array (15) Each output end of each is connected with one end of each group of optical fiber photoacoustic sensing probes in one-to-one correspondence.
  5. 根据权利要求4所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述半导体激光器1为中心波长1530nm的近红外DFB激光器。The distributed on-line monitoring system for decomposition products of sulfur hexafluoride according to claim 4, wherein the semiconductor laser 1 is a near-infrared DFB laser with a center wavelength of 1530 nm.
  6. 根据权利要求1所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述光纤光声传感探头有3个，分别为第一光纤光声传感探头(12)、第二光纤光声传感探头(13)以及第三光纤光声传感探头(14)，第一光纤光声传感探头(12)、第二光纤光声传感探头(13)以及第三光纤光声传感探头(14)分别连接光纤阵列(15)一个输出端。A distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 1, characterized in that there are three optical fiber photoacoustic sensing probes, which are respectively the first optical fiber photoacoustic sensing probes (12) , the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe (14), the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe (13) The three optical fiber photoacoustic sensing probes (14) are respectively connected to one output end of the optical fiber array (15).
  7. 根据权利要求1所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述光纤阵列(15)的输出端个数大于等于光纤光声传感探头的个数。The distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 1, characterized in that the number of output ends of the optical fiber array (15) is greater than or equal to the number of optical fiber photoacoustic sensing probes.
  8. 根据权利要求6所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述第一光纤光声传感探头(12)、第二光纤光声传感探头(13)及第三光纤光声传感探头(14)结构相同，均包括声波敏感膜片(18)、气 室(19)、光纤端面(20)、光纤准直器(21)及外壳(22)，所述外壳(22)内平行布置光纤端面(20)和光纤准直器(21)，光纤端面(20)和光纤准直器(21)形状相同且光纤端面(20)的一端向外壳(22)外延伸出一个光纤探头通过光纤阵列(15)与探测光源装置连接，光纤准直器(21)的一端向外壳(22)外延伸出一个光纤探头通过光纤阵列(15)与激发光源装置连接；所述气室(19)包括光声管和导气通道，所述光声管水平设置且一端与光纤准直器(21)另一端衔接，导气通道竖直设置且上端与光声管的另一端相通，导气通道的下端与光纤端面(20)的另一端衔接，所述导气通道右侧平行设置声波敏感膜片(18)，声波敏感膜片(18)作为外壳(22)的右侧面。A distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 6, characterized in that the first optical fiber photoacoustic sensing probe (12), the second optical fiber photoacoustic sensing probe (13) and the third optical fiber photoacoustic sensing probe (14) have the same structure, and both include an acoustic wave sensitive diaphragm (18), an air chamber (19), an optical fiber end face (20), an optical fiber collimator (21) and a housing (22), An optical fiber end face (20) and an optical fiber collimator (21) are arranged in parallel in the housing (22), the optical fiber end face (20) and the optical fiber collimator (21) have the same shape and one end of the optical fiber end face (20) faces the housing (22 ) to extend a fiber optic probe through the fiber array (15) to connect with the detection light source device, and one end of the fiber collimator (21) extends a fiber probe to the outside of the housing (22) to connect with the excitation light source device through the fiber array (15) ; The gas chamber (19) includes a photoacoustic tube and an air guide channel, the photoacoustic tube is horizontally arranged and one end is connected with the other end of the fiber collimator (21), the air guide channel is vertically arranged and the upper end is connected to the photoacoustic tube The other end of the air guide channel is connected to the other end of the fiber end face (20), and the right side of the air guide channel is provided with a sound wave sensitive diaphragm (18) in parallel, and the sound wave sensitive diaphragm (18) is used as the shell (22) right side of the .
  9. 根据权利要求8所述的一种六氟化硫分解产物分布式在线监测***，其特征在于，所述声波敏感膜片(18)上开设一个悬臂梁结构(181)，所述悬臂梁结构(181)为自由端向下的矩形槽，外部待测气体通过声波敏感膜片(18)上的悬臂梁结构(181)的槽缝扩散到气室(19)内。A distributed on-line monitoring system for sulfur hexafluoride decomposition products according to claim 8, characterized in that a cantilever beam structure (181) is provided on the acoustic wave sensitive diaphragm (18), and the cantilever beam structure ( 181) is a rectangular groove with the free end facing down, and the external gas to be measured diffuses into the air chamber (19) through the slot of the cantilever beam structure (181) on the acoustic wave sensitive diaphragm (18).
  10. 根据权利要求1-9任一项所述的一种六氟化硫分解产物分布式在线监测***的方法，其特征在于，发射紫外光的第一激发光源装置用于对SF 6电器设备中SO 2进行探测，发射近红外光的第二激发光源装置用于对SF 6电器设备中H 2S进行探测，通过选择接通其中一组激发光源装置或者分时接通两组激发光源装置，实现SO 2气体单独检测、H 2S气体单独检测或者SO 2、H 2S气体分时检测，每组光纤光声传感探头置于不同的监测区域，通过选择接通其中一个监测区域或者分时接通多个监测区域对应的光纤光声传感探头实现一个监测区域的气体检测或者多个监测区域的气体分时检测， 整个***进行分布式检测。 The method of a distributed on-line monitoring system for decomposition products of sulfur hexafluoride according to any one of claims 1-9, wherein the first excitation light source device emitting ultraviolet light is used to detect SO in SF6 electrical equipment. 2 for detection, the second excitation light source device that emits near-infrared light is used to detect H 2 S in SF 6 electrical equipment, by selectively connecting one group of excitation light source devices or connecting two groups of excitation light source devices in time-sharing, to realize Separate detection of SO 2 gas, single detection of H 2 S gas or time-sharing detection of SO 2 and H 2 S gas. Each group of optical fiber photoacoustic sensing probes is placed in a different monitoring area. The fiber optic photoacoustic sensing probes corresponding to multiple monitoring areas are connected to realize gas detection in one monitoring area or time-sharing detection of gas in multiple monitoring areas, and the whole system performs distributed detection.
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