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CN109000712A - Cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method - Google Patents

Cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method Download PDF

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Publication number
CN109000712A
CN109000712A CN201810510221.1A CN201810510221A CN109000712A CN 109000712 A CN109000712 A CN 109000712A CN 201810510221 A CN201810510221 A CN 201810510221A CN 109000712 A CN109000712 A CN 109000712A
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China
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laser
probe
fiber grating
light
photodetector
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Inventor
魏玉宾
葛少伟
王寅
刘统玉
李艳芳
马聪
牟泽刚
姜涛
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Jinan Power Supply Co of State Grid Shandong Electric Power Co Ltd
Laser Research Institute
State Grid Corp of China SGCC
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Jinan Power Supply Co of State Grid Shandong Electric Power Co Ltd
Laser Research Institute
State Grid Corp of China SGCC
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Application filed by Jinan Power Supply Co of State Grid Shandong Electric Power Co Ltd, Laser Research Institute, State Grid Corp of China SGCC filed Critical Jinan Power Supply Co of State Grid Shandong Electric Power Co Ltd
Priority to CN201810510221.1A priority Critical patent/CN109000712A/en
Publication of CN109000712A publication Critical patent/CN109000712A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/58—Radiation pyrometry, e.g. infrared or optical thermometry using absorption; using extinction effect
    • 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
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Optics & Photonics (AREA)
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  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

本发明公开了电缆隧道多参数光纤分布式传感测量装置，完成对电缆隧道内参数在线监测，包括激光发射单元、激光基准信号单元、激光反馈信号单元、控制单元、分布式探头阵列，激光发射单元的控制端与控制单元的输出端连接，激光发射单元的输出端一路与激光基准信号单元的输入端连接，另一路与分布式探头阵列的输入端连接，分布式探头阵列的输出端与激光反馈信号单元的输入端连接，激光反馈单元的输出端与控制单元的输入端连接。实现电缆隧道内温度、湿度以及气体浓度参数的同时在线监测，结构简单、功耗低且本质安全。

The invention discloses a multi-parameter optical fiber distributed sensing and measuring device for a cable tunnel, which completes online monitoring of parameters in the cable tunnel, including a laser emitting unit, a laser reference signal unit, a laser feedback signal unit, a control unit, a distributed probe array, and a laser emitting unit. The control terminal of the unit is connected to the output terminal of the control unit, one of the output terminals of the laser emitting unit is connected to the input terminal of the laser reference signal unit, and the other is connected to the input terminal of the distributed probe array, and the output terminal of the distributed probe array is connected to the laser The input end of the feedback signal unit is connected, and the output end of the laser feedback unit is connected with the input end of the control unit. Realize the simultaneous online monitoring of temperature, humidity and gas concentration parameters in the cable tunnel, with simple structure, low power consumption and intrinsic safety.

Description

Cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method
Technical field
The present invention relates to technical field of optical fiber sensing, are based especially on the multi-parameter distributed sensing of optical time-domain analysis technology System is mainly used in the multiple spot Distributed Detection of temperature in cable tunnel, humidity and gas concentration.
Background technique
In recent years, with the growth of China's economic strength and the demand of Process of Urbanization Construction, State Grid Corporation of China increases defeated Power grid cables dynamics of investment refreshes the total mileage of cable tunnel constantly.China has become cable tunnel in the world at present At most, the most fast country of development.Consequent is that the demand of cable tunnel operation management is greatly increased, wherein right It is essential in the detection of temperature, humidity and corresponding gas concentration in cable tunnel.However, for upper in current cable tunnel The detection sensor for stating parameter still rests on the stage of a variety of detection means and relevant device assembling combination mostly, not only senses Structure is complicated for device, and transducing signal is many and diverse, data transfer demands amount is big, apply at the scene in system power dissipation is big, stability is poor And it is difficult to realize the essential safety of monitoring.Currently, simple structure, low in energy consumption, essential safety and can are still lacked in cable tunnel With the system and device detected simultaneously to temperature, humidity and gas concentration, so that temperature, humidity and gas in cable tunnel The on-line monitoring of bulk concentration parameter is difficult to effectively implement.
Summary of the invention
The object of the present invention is to provide cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method, realize It is monitored on-line while temperature, humidity and gas concentration parameters in cable tunnel, structure is simple, low in energy consumption and essential safety.
To achieve the above object, the present invention adopts the following technical solutions:
First invention of the present invention provides a kind of cable tunnel multi-parameter distributed fiber-optic sensor measuring device, completes to electricity Cable tunnel intrinsic parameter on-line monitoring, including laser emission element, laser datum signal element, Laser feedback signal element, control Unit, distributed linear transducer array, the control terminal of laser emission element and the output end of control unit connect, laser emission element Output end is connect with the input terminal of laser datum signal element all the way, and another way is connect with the input terminal of distributed linear transducer array, The output end of distributed linear transducer array is connect with the input terminal of Laser feedback signal element, the output end of Laser feedback unit and control The input terminal of unit processed connects.
Further, laser emission element includes first laser device and second laser, first laser device and second laser The input terminal of device is electrically connected with laser high-frequency driving circuit/temperature control circuit respectively, laser high-frequency driving circuit/temperature control circuit It is electrically connected with control unit；The pulse laser beam that first laser device and second laser issue enters the after the first beam splitter Two beam splitters, a branch of after the second beam splitter beam splitting to enter laser datum signal element, another beam enters distributed linear transducer array.
Further, the laser datum signal element includes third wavelength division multiplexer, third photodetector and the 4th Photodetector；Light into laser datum signal element is allocated as two beams after third wavelength division multiplexer, and first laser device goes out It penetrates light and enters third photodetector, the emergent light of second laser enters the 4th photodetector；Third photodetector and The photosignal that 4th photodetector responds is sent to control unit by the acquisition of multi-channel high-speed data Acquisition Circuit, makees For the reference signal of optical signal analysis.
Further, another beam emergent light of the second beam splitter enters the second wavelength division multiplexer all the way after circulator, the The emergent light of two wavelength division multiplexers is divided into two bundles: the emergent light of first laser device and the emergent light of second laser respectively enter point Cloth linear transducer array；The reflected light of distributed linear transducer array is returned according to original route, and it is multiple that first wave point is entered after circulator With device, the emergent light of the first wavelength division multiplexer is allocated as two beams, the reflected light pass of first laser device to the first photodetector, and The reflected light pass of dual-laser device is to the second photodetector；The output photoelectric of first photodetector and the second photodetector Signal is connect with multi-channel high-speed data Acquisition Circuit, and multi-channel high-speed data Acquisition Circuit is electrically connected with control unit.
Further, the distributed linear transducer array includes the probe of several series connections, is concatenated between adjacent two probe There is the delayer for amplifying laser signal；The probe includes gas chamber, the first fiber grating, the second fiber grating and third light Fine grating；First fiber grating and the second fiber grating characteristic wavelength are different, first laser device emergent light the first light of directive Fine grating rear portion light is reflected along original route, a part of directive of emergent light after another part light the second fiber grating of directive Delayer, another part are reflected along original route；The emergent light of second laser directive after gas chamber is absorbed by under test gas Three fiber gratings, a part of directive delayer of emergent light, another part are reflected along original route.
Further, the plenum surface is provided with several holes, and gas chamber is connected by hole with external environment, completes Extraneous environmental gas is detected.
Second aspect of the present invention provides cable tunnel multi-parameter distributed fiber-optic sensor measurement method, specific as follows:
The reflection echo signal of the different probes of distributed linear transducer array will reach the first photodetector in different moments With the second photodetector, by being demodulated to the echo-signal in time domain, realize to temperature at different probes, humidity and The demodulation of gas concentration information.
Further, first laser device outgoing light wavelength is scanned by short and length, and demodulation obtains distributed linear transducer array In the first fiber grating reflection echo signal IT1’、IT2’、……、ITn' and the second fiber grating reflection echo signal IH1’、 IH2’、……、IHn'；By monitoring the drift of reflection echo signal wavelength, temperature and wet is completed according to fiber grating characteristic parameter Spend the deduction of detection parameters.
Further, a beam intensity of second laser is IG0Pulse reach first probe, first probe in by gas Intensity becomes I after gas in room absorbsG1, after the part reflection of the third fiber grating of the first probe, a part of pulse Light beam is reflected, intensity IG1r31, another part pulsed light beam is transmitted through third fiber grating, and it is backward to pass through delayer It pops one's head in and transmits, intensity IG1t31；Wherein r31For first probe in third fiber grating reflectivity, and transmit intensity For IG1t31Pulsed light beam by second probe in gas indoor gas absorption after its intensity become IG2, reflect a part of pulse Light beam, intensity IG2r31, transmit a part of pulsed light beam, intensity IG2t31；And so on, until the n that pops one's head in；
For the echo-signal I for 1 fiber grating 3 of popping one's head inG1',
Wherein, α1For constant related with gas chamber in the first probe and under test gas characteristic absorption wavelength, c1For gas Indoor Air The concentration of body；
Similarly, for the echo-signal I for 2 fiber gratings 3 of popping one's head inG2',
And so on, for echo-signal IGn',
Based on formula (1)-(n), pass through the echo-signal I of acquisitionG1’、IG2’、……、IGn', may finally inverting obtain The concentration value of under test gas at each probe.
The effect provided in summary of the invention is only the effect of embodiment, rather than invents all whole effects, above-mentioned A technical solution in technical solution have the following advantages that or the utility model has the advantages that
1, the device of temperature, humidity and gas concentration parameters detection is serially connected on optical fiber by the present invention, to more ginsengs When number is detected, the simple concatenation by multiple sensors is realized to the leap of system effective integration, really proposes one kind one Multi-parameter (temperature, humidity, gas concentration) detection device of body；
2, system uses optical time-domain analysis technology, and beam of laser pulse can realize multiple spot while detect, and greatly improve light source Utilization efficiency；
3, detection device uses distributed frame, only can be realized by two optical fiber to multiple to be measured within the scope of long range The detection of point, greatly reduces the quantity of probe source, effectively reduces the power consumption of detection system, while price is cheaper；
4, in monitoring field, proposed detection device is the optical fiber transmission of optical signal, from the influence of electromagnetic interference, and Detection process without hot line job, has essential safety attribute at the scene.
Detailed description of the invention
Fig. 1 is cable tunnel multi-parameter distributed fiber-optic sensor measuring device structural schematic diagram of the present invention；
Fig. 2 is the distribution of optical signal and the explanation schematic diagram of echo-signal in each probe of the invention.
Specific embodiment
In order to clarify the technical characteristics of the invention, below by specific embodiment, and its attached drawing is combined, to this hair It is bright to be described in detail.Following disclosure provides many different embodiments or example is used to realize different knots of the invention Structure.In order to simplify disclosure of the invention, hereinafter the component of specific examples and setting are described.In addition, the present invention can be with Repeat reference numerals and/or letter in different examples.This repetition is that for purposes of simplicity and clarity, itself is not indicated Relationship between various embodiments and/or setting is discussed.It should be noted that illustrated component is not necessarily to scale in the accompanying drawings It draws.Present invention omits the descriptions to known assemblies and treatment technology and process to avoid the present invention is unnecessarily limiting.
System and device proposed by the invention as shown in Figure 1, mainly by laser high-frequency driving circuit/temperature control circuit, swash Light device 1, laser 2, beam splitter 1, beam splitter 2, circulator, wavelength division multiplexer 1, wavelength division multiplexer 2, wavelength division multiplexer 3, delay Device, photodetector 1 (PD1), photodetector 2 (PD2), photodetector 3 (PD3), photodetector 4 (PD4), multichannel High Speed Data Acquisition Circuit, microcontroller (MCU) and distributed linear transducer array.
Wherein distributed linear transducer array by probe 1, probe 2 ..., probe n forms.Each probe is by gas chamber, light Fine grating 1, fiber grating 2 and fiber grating 3 form.Wherein fiber grating 1 is different from the characteristic wavelength of fiber grating 2, point It Yong Yu not be to the perception of environment temperature and humidity, and with the variation of environment temperature and humidity, the characteristic wavelength of two fiber gratings It will not be overlapped.Fiber grating 3 is chirp grating, and gas to be measured can be completely covered in characteristic wavelength wider range of reflection The broadening of body absorption peak.
Laser 1 is electrically connected with laser high-frequency driving circuit/temperature control circuit respectively with laser 2, receives driving, temperature control The control of circuit.Photodetector 1, photodetector 2, photodetector 3, photodetector 4 are adopted with multi-channel high-speed data Collector electrical connection, multi-channel high-speed data Acquisition Circuit are electrically connected with MCU, and multi-channel high-speed data Acquisition Circuit is in microcontroller The photosignal that acquisition photodetector generates under the control of device further will acquire signal feeding microcontroller and carry out calculating solution It adjusts.Laser, beam splitter, circulator, wavelength division multiplexer, delayer, probe and fiber grating in probe, gas chamber is according to such as Mode shown in FIG. 1 is connected by optical fiber.
Gas chamber is connected by punching thereon with external environment, for detecting to the gas in environment.Laser 1 It is corresponding with fiber grating 1, the fiber grating 2 in probe, the active probe light source as environment temperature, humidity.1 wave of laser The characteristic wavelength of long scan range covering fiber grating 1 and fiber grating 2.Even if environment temperature and humidity change, light The characteristic wavelength of fine grating 1 and fiber grating 2 is still within the scope of the scanning wavelength of laser 1.
Laser 2 is corresponding with the fiber grating 3 in probe, and as the active probe light source of gas concentration, wavelength is swept It is consistent with the wavelength where the Absorption Characteristics spectrum of under test gas to retouch range.
Under laser high-frequency driving circuit/temperature control circuit drive control, laser 1 is launched respectively with laser 2 The pulse laser beam of length scanning.The pulse laser beam that two-laser is launched after beam splitter 1 enter same root optical fiber into Row transmission.After 2 beam splitting of beam splitter, a part enters circulator, and another part enters wavelength division multiplexer 3.It is multiple into wavelength-division It is divided into two beams according to wavelength difference after being divided with that a part of device 3, a branch of emergent light for laser 1, another beam is sharp The emergent light of light device 2.Two pulses light arrives separately at photodetector 3 (PD3) and photodetector 4 (PD4) and responds out light Electric signal.Gained photosignal is obtained by multi-channel high-speed data Acquisition Circuit and the reference signal as optical signal analysis.Through It crosses another beam pulse light that beam splitter 2 separates and reaches wavelength division multiplexer 2 after circulator guides.
It is emitted from two-laser and the pulse laser beam with different wave length is divided into two beams by wavelength division multiplexer 2, wherein one The light beam that beam is emitted by laser 1 is transmitted into probe 1 and towards fiber grating 1 and fiber grating 2；Another beam is sharp The light beam that light device 2 is emitted is transmitted into probe 1 and towards gas chamber, fiber grating 3.The laser beam-wave that laser 1 is launched The long ascending characteristic wavelength for being initially coated with fiber grating 1, passes through the variation of the drift sense ambient temperature of its characteristic wavelength； The characteristic wavelength of further covering fiber grating 2 is passed through into its characteristic wavelength then as the red shift of laser beam-wave long scan The variation of drift perception ambient humidity.After the light beam that laser 1 is emitted enters probe 1, in the short-wave band section of scanning by optical fiber 1 part of grating reflection, another part energy transmission, and fiber grating 2 for this wave band without any reflection effect, light beam is completely saturating It penetrates；In the long-wave band section of scanning, laser beam is reflected by 2 part of fiber grating, another part energy transmission, and fiber grating 1 For this wave band without any reflection effect, light beam is wholly transmissive.After the light beam that laser 2 is emitted enters probe 1, gas is first passed around Room is simultaneously partially absorbed by under test gas, and remaining beam energy is further to fiber grating 3 and is partially reflected, another part light Beam transmission.
The light beam of reflection is returned along incident original route, and the light beam by corresponding to two-laser after wavelength division multiplexer 2 closes Two is are transmitted to circulator together, and reach wavelength division multiplexer 1 by the guidance of circulator.Pulsed light beam passes through wavelength division multiplexer 1 light splitting is again broken down into two beams, wherein a branch of correspond to laser 1, and is transmitted to photodetector 1 and causes photosignal, should Photosignal has reacted the response message of fiber grating 1 and fiber grating 2 in probe, to carry temperature and humidity at probe Information；Another beam corresponds to laser 2, and is transmitted to photodetector 2 and causes photosignal, and the photosignal is by optical fiber light Grid 3 reflect and reflect gas indoor gas in probe, and it is dense to carry gas at probe to the absorbing state of 2 outgoing beam of laser Spend information.In probe 1, the light beam transmitted will all continue to be transmitted to spy either from laser 1 or laser 2 Delayer between first 1 and probe 2.Delayer increases the light path of pulse laser beam transmission, to extend the time of its transmission.Through Light beam continues to be transmitted in probe 2 after crossing delayer, and repeats its circulation way in probe 1.And so on, correspond to two The detection light beam of sublaser will each probe occur part reflection and fractional transmission, transmitted light beam will successively from probe 1 by It is a to be transmitted to probe n.At probe n, fiber grating 1, fiber grating 2 and fiber grating 3 are to corresponding reflected waveband It is totally reflected.
For photodetector 1 and photodetector 2, the echo-signal of difference probe will successively be reached in different moments, A series of echo-signals are formed with identical interval in the time domain.By being demodulated to the echo-signal in time domain, will realize Demodulation to temperature, humidity and gas concentration information at different probes.
The wavelength of 1 outgoing pulse light beam of laser is scanned by short and length, and probe inner fiber grating 1 can be completely covered With the reflectance signature wavelength of fiber grating 2.Temperature, humidity in the reflectance signature wavelength of grating and probe in environment to be measured is at line Sexual intercourse, by detect two gratings reflectance signature wavelength and its drift can to the temperature and humidity parameter in each probe into Row inverting demodulation.
As shown in Fig. 2, obtaining the reflection echo signal I of fiber grating 1 in each probe in demodulationT1’、IT2’、……、 ITn' and fiber grating 2 reflection echo signal IH1’、IH2’、……、IHn'.By monitoring the drift of echo-signal wavelength, root According to the characteristic parameter of fiber grating, the inverting of relevant temperature and humidity parameter can be fast implemented.
The pulsed light beam energy that laser 2 is emitted is equally divided into two beams by beam splitter 2, and a branch of arrival photodetection 4 causes Intensity is IG0Photosignal.Another beam intensity is IG0Pulse reach probe 1.It is absorbed in probe 1 by the gas in gas chamber Intensity becomes I afterwardsG1, after the reflection of the part of fiber grating 3, a part of pulsed light beam is reflected, intensity IG1r31, separately A part of pulsed light beam transmits, intensity I transmitted through grating, and after delayer to probeG1t31.Wherein r31To visit The reflectivity of fiber grating 3 in first 1.And the intensity transmitted is IG1t31Pulsed light beam by probe 2 in gas indoor gas suction Its intensity becomes I after receiptsG2, the process being similar in probe 1 then occurs, reflects a part of pulsed light beam, intensity is IG2r31, transmit a part of pulsed light beam, intensity IG2t31.This process and so on, until the n that pops one's head in.For 1 optical fiber of popping one's head in The echo-signal I of grating 3G1',
Wherein α1For constant related with gas chamber in probe 1 and under test gas characteristic absorption wavelength, c1For gas indoor gas Concentration.Similarly, for the echo-signal I for 2 fiber gratings 3 of popping one's head inG2',
And so on, for echo-signal IGn',
Based on formula (1)-(n), pass through the echo-signal I of acquisitionG1’、IG2’、……、IGn' may finally inverting obtain respectively The concentration value of under test gas at a probe.
By taking the detection of temperature, humidity and methane gas in cable tunnel as an example.Choose laser 1 central wavelength be 1530nm, scanning range are 1528nm to 1532nm.The central wavelength for choosing laser 2 is 1653.7, scanning range 1nm, first Alkane gas has significant Absorption Characteristics peak in this wave band.Microcontroller is using certain time interval T as the period, to laser driving circuit Stair-stepping digital signal is sent, i.e. digital signal value is sequentially increased over time, shows ladder-like, but each side The period of wave signal is T；In bigger time range T0, microcontroller is repeated the above process, and repetition exports above-mentioned ladder The discrete signal of shape.Laser driving circuit, which converts this stair-stepping periodic digital signal to using time T0 as modulus of periodicity, to be intended Sawtooch sweep current signal, and its lasting control electric current input for being injected into laser 1 and laser 2 is drawn respectively Foot.Two-laser swashs in the lasting output wavelength pulse from short to long of the control periodical of this sawtooch sweep current signal Light beam.
The pulse laser beam of two-laser outgoing enters an optical fiber by beam splitter 1 and is split by beam splitter 2. A part, by being further divided into two beams by wave band after wavelength division multiplexer 3, respectively the emergent light of laser 1 and swashs as reference light The emergent light of light device 2.Two pulsed light beams cause the response of photodetector 3 Yu photodetector 4 respectively, generate final reference Signal.Another beam pulse that beam splitter 2 separates enters wavelength division multiplexer 2 under the guidance of circulator and is divided.With above-mentioned wave Situation in division multiplexer 3 is similar, and pulsed light beam is divided into two beams, a branch of to be emitted by laser 1, and another beam is laser 2 It is emitted.Two pulses are transmitted along two optical fiber respectively, successively by probe 1, probe 2 ..., probe n and probe Between delayer.In each probe, when the outgoing pulse light beam scanning wave band of laser 1 is located at 1528nm to 1530nm wave Duan Shi, the outgoing pulse part from laser 1 are reflected by fiber grating 1, remaining transmission, and fiber grating 2 is for the wave Section pulse without any reflex, completely through.The pulsed light in this wave band by by the fiber grating 1 in each probe successively Reflection, and different moments in the time domain eventually arrive at photodetector 1.By each moment in 1 gained time domain of photodetector Acquired echo-signal takes ratio for removing the shake of laser 1 with 3 gained reference signal of photodetector respectively, thus It is accurately obtained the wavelength of reflected light signal.Relationship based on fiber grating reflectance signature wavelength and environment temperature, when passing through demodulation The detection to environment temperature at each probe positions may be implemented in the wavelength of the reflected light signal at each moment on domain.Similar, When 1 outgoing pulse light beam of laser scanning wave band is in 1530nm to 1532nm wave band, the fiber grating 1 in each probe is right Pulsed light beam is without any reflex, and fiber grating 2 has part reflex for pulsed light beam.Arteries and veins in this wave band Washing off will successively be reflected by the fiber grating 2 in each probe, and different moments in the time domain eventually arrive at photodetector 1.It is same as described above, by echo-signal acquired in each moment in 1 gained time domain of photodetector respectively with photodetector 3 Gained reference signal takes ratio for removing the shake of laser 1, to be accurately obtained the wavelength of reflected light signal.Based on optical fiber The relationship of optical grating reflection characteristic wavelength and ambient humidity, can be with by the wavelength of the reflected light signal at each moment in demodulation time domain Realize the detection to ambient humidity at each probe positions.Laser 2 be emitted pulse laser scanning wavelength be with 1653.7nm Central wavelength, using 1nm as scanning range.It, can be in entire 2 outgoing pulse of laser since fiber grating 3 belongs to chirp grating There is part reflex to pulsed light in optical scanning wavelength band.In each probe, corresponding pulsed light passes through gas chamber When partially absorbed by the under test gas in it.The echo signal intensity of each probe and the concentration of gas chamber in each probe are showed For example described formula (the 1)-formula (n) of relationship stated.Photodetector 2 will successively respond 2 outgoing pulse light beam of laser Echo-signal, and acquired in multi-channel high-speed data Acquisition Circuit.It is closed according to recursion described in formula (1)-formula (n) It is that the processing routine in microcontroller successively demodulation inverting will obtain the concentration value of methane gas in gas chamber.Laser 1 and laser Device 2 respectively works independently, and due to using wavelength division multiplexer, two-laser outgoing pulse light beam is mutually noiseless, in time domain Echo-signal is responded by two photodetectors respectively and is sent into multi-channel high-speed data Acquisition Circuit system.It is demodulated in signal Cheng Zhong, the two are mutually indepedent.Only one wavelength of the pulsed light that laser is emitted every time, and each outgoing over time The wavelength of pulse gradually increases, and until entire scan period T0 terminates, restarts new one and discusses scanning process.Although laser 1 Both for being also used for the detection to humidity to the detection of temperature, but due to the mode of laser pulse output, for temperature The echo-signal that the detection of degree is reflected using fiber grating 1 reflects the detection of humidity using fiber grating 2 Echo-signal.Two groups of echo-signals are completely independent separation in the time domain, and same nothing interferes with each other.
Above-mentioned, although the foregoing specific embodiments of the present invention is described with reference to the accompanying drawings, not protects model to the present invention The limitation enclosed, those skilled in the art should understand that, based on the technical solutions of the present invention, those skilled in the art are not Need to make the creative labor the various modifications or changes that can be made still within protection scope of the present invention.

Claims (9)

1.电缆隧道多参数光纤分布式传感测量装置，完成对电缆隧道内参数在线监测，其特征是，包括激光发射单元、激光基准信号单元、激光反馈信号单元、控制单元、分布式探头阵列，激光发射单元的控制端与控制单元的输出端连接，激光发射单元的输出端一路与激光基准信号单元的输入端连接，另一路与分布式探头阵列的输入端连接，分布式探头阵列的输出端与激光反馈信号单元的输入端连接，激光反馈单元的输出端与控制单元的输入端连接。1. The cable tunnel multi-parameter optical fiber distributed sensing and measuring device completes the on-line monitoring of the parameters in the cable tunnel. It is characterized in that it includes a laser emitting unit, a laser reference signal unit, a laser feedback signal unit, a control unit, and a distributed probe array. The control end of the laser emitting unit is connected to the output end of the control unit, one of the output ends of the laser emitting unit is connected to the input end of the laser reference signal unit, the other is connected to the input end of the distributed probe array, and the output end of the distributed probe array is It is connected with the input end of the laser feedback signal unit, and the output end of the laser feedback unit is connected with the input end of the control unit. 2.如权利要求1所述的电缆隧道多参数光纤分布式传感测量装置，其特征是，激光发射单元包括第一激光器和第二激光器，第一激光器和第二激光器的输入端分别与激光器高频驱动电路/温控电路电连接，激光器高频驱动电路/温控电路与控制单元电连接；第一激光器与第二激光器发出的脉冲激光束经过第一分束器后进入第二分束器，第二分束器分束后一束进入激光基准信号单元，另一束进入分布式探头阵列。2. cable tunnel multi-parameter optical fiber distributed sensing measurement device as claimed in claim 1, is characterized in that, laser emission unit comprises first laser and second laser, and the input end of first laser and second laser is connected with laser respectively The high-frequency drive circuit/temperature control circuit is electrically connected, and the laser high-frequency drive circuit/temperature control circuit is electrically connected to the control unit; the pulsed laser beams emitted by the first laser and the second laser enter the second beam splitter after passing through the first beam splitter After splitting by the second beam splitter, one beam enters the laser reference signal unit, and the other beam enters the distributed probe array. 3.如权利要求2所述的电缆隧道多参数光纤分布式传感测量装置，其特征是，所述激光基准信号单元包括第三波分复用器、第三光电探测器和第四光电探测器；进入激光基准信号单元的光经第三波分复用器后分作两束，第一激光器的出射光进入第三光电探测器，第二激光器的出射光进入第四光电探测器；第三光电探测器和第四光电探测器响应得到的光电信号由多通道高速数据采集电路获取发送至控制单元，作为光信号分析的参考信号。3. cable tunnel multi-parameter optical fiber distributed sensing and measuring device as claimed in claim 2, is characterized in that, described laser reference signal unit comprises the 3rd wavelength division multiplexer, the 3rd photodetector and the 4th photodetector The light entering the laser reference signal unit is divided into two beams by the third wavelength division multiplexer, the outgoing light of the first laser enters the third photodetector, and the outgoing light of the second laser enters the fourth photodetector; The photoelectric signals obtained by the responses of the three photodetectors and the fourth photodetector are acquired by the multi-channel high-speed data acquisition circuit and sent to the control unit as reference signals for optical signal analysis. 4.如权利要求2所述的电缆隧道多参数光纤分布式传感测量装置，其特征是，第二分束器另一束出射光经过环形器后一路进入第二波分复用器，第二波分复用器的出射光分为两束：第一激光器的出射光和第二激光器的出射光分别进入分布式探头阵列；分布式探头阵列的反射光按照原路径返回，经过环形器后进入第一波分复用器，第一波分复用器的出射光分作两束，第一激光器的反射光传输至第一光电探测器，第二激光器的反射光传输至第二光电探测器；第一光电探测器和第二光电探测器的输出光电信号与多通道高速数据采集电路连接，多通道高速数据采集电路与控制单元电连接。4. The cable tunnel multi-parameter optical fiber distributed sensing and measuring device as claimed in claim 2, characterized in that, another bundle of outgoing light from the second beam splitter enters the second wavelength division multiplexer all the way through the circulator, and the first The outgoing light of the two-wavelength division multiplexer is divided into two beams: the outgoing light of the first laser and the outgoing light of the second laser enter the distributed probe array respectively; the reflected light of the distributed probe array returns according to the original path, and after passing through the circulator Entering the first wavelength division multiplexer, the output light of the first wavelength division multiplexer is divided into two beams, the reflected light of the first laser is transmitted to the first photodetector, and the reflected light of the second laser is transmitted to the second photodetector device; the output photoelectric signals of the first photodetector and the second photodetector are connected to the multi-channel high-speed data acquisition circuit, and the multi-channel high-speed data acquisition circuit is electrically connected to the control unit. 5.如权利要求4所述的电缆隧道多参数光纤分布式传感测量装置，其特征是，所述分布式探头阵列包括若干串联连接的探头，相邻两探头之间串接有用来放大激光信号的延时器；所述探头包括气室、第一光纤光栅、第二光纤光栅和第三光纤光栅；所述第一光纤光栅和第二光纤光栅特征波长不同，第一激光器出射光射向第一光纤光栅后一部分光线沿原路径反射，另一部分光线射向第二光纤光栅后出射光一部分射向延时器，另一部分沿原路径反射；第二激光器的出射光经过气室被待测气体吸收后射向第三光纤光栅，出射光一部分射向延时器，另一部分沿原路径反射。5. The cable tunnel multi-parameter optical fiber distributed sensing and measuring device as claimed in claim 4, wherein the distributed probe array includes some probes connected in series, and the adjacent two probes are connected in series to amplify the laser light. signal delay device; the probe includes an air chamber, a first fiber grating, a second fiber grating and a third fiber grating; the first fiber grating and the second fiber grating have different characteristic wavelengths, and the first laser emits light A part of the light after the first fiber grating is reflected along the original path, another part of the light is directed to the second fiber grating, and part of the outgoing light is directed to the delay device, and the other part is reflected along the original path; the outgoing light of the second laser passes through the gas chamber and is tested The gas absorbs and shoots to the third fiber grating, part of the outgoing light goes to the delayer, and the other part is reflected along the original path. 6.如权利要求4所述的电缆隧道多参数光纤分布式传感测量装置，其特征是，所述气室表面设置有若干孔洞，气室通过孔洞与外界环境相连通，完成对外界环境气体进行检测。6. The cable tunnel multi-parameter optical fiber distributed sensing and measuring device as claimed in claim 4, characterized in that, the surface of the air chamber is provided with a number of holes, and the air chamber communicates with the external environment through the holes to complete the monitoring of the external environment gas. to test. 7.电缆隧道多参数光纤分布式传感测量方法，其特征是，具体如下：7. The cable tunnel multi-parameter optical fiber distributed sensing measurement method is characterized in that it is as follows: 分布式探头阵列的不同探头的反射回波信号将在不同时刻到达第一光电探测器和第二光电探测器，通过对时域上的回波信号进行解调，实现对不同探头处温度、湿度以及气体浓度信息的解调。The reflected echo signals of different probes in the distributed probe array will reach the first photodetector and the second photodetector at different times, and the temperature and humidity at different probes can be realized by demodulating the echo signals in the time domain. And the demodulation of gas concentration information. 8.如权利要求7所述的电缆隧道多参数光纤分布式传感测量方法，其特征是，第一激光器出射光波长由短及长进行扫描，解调获取分布式探头阵列中第一光纤光栅反射回波信号IT1’、IT2’、……、ITn’以及第二光纤光栅的反射回波信号IH1’、IH2’、……、IHn’；通过监测反射回波信号波长的漂移，根据光纤光栅特征参数完成温度和湿度检测参数的推演。8. The cable tunnel multi-parameter optical fiber distributed sensing measurement method as claimed in claim 7, characterized in that the wavelength of the light emitted by the first laser is scanned from short to long, and demodulated to obtain the first fiber grating in the distributed probe array Reflected echo signals I T1 ', I T2 ', ..., I Tn ' and reflected echo signals I H1 ', I H2 ', ..., I Hn ' of the second fiber grating; by monitoring the reflected echo signal wavelength The drift of the temperature and humidity detection parameters is deduced according to the characteristic parameters of the fiber grating. 9.如权利要求7所述的电缆隧道多参数光纤分布式传感测量方法，其特征是，第二激光器的一束强度为IG0的脉冲到达第一探头，在第一探头中被气室中的气体吸收后强度变为IG1，经过第一探头的第三光纤光栅的部分反射后，一部分脉冲光束被反射，其强度为IG1r31，另一部分脉冲光束透射过第三光纤光栅，并经过延时器后向探头而传输，其强度为IG1t31；其中r31为第一探头中第三光纤光栅的反射率，而透射的强度为IG1t31的脉冲光束经过第二探头中气室内气体的吸收后其强度变为IG2，反射一部分脉冲光束，其强度为IG2r31，透射一部分脉冲光束，其强度为IG2t31；依次类推，直到探头n；9. cable tunnel multi-parameter optical fiber distributed sensing measurement method as claimed in claim 7, is characterized in that, a bundle of intensity of the second laser is that the pulse of I G0 arrives at the first probe, is in the first probe by the gas chamber After the absorption of the gas in the gas, the intensity becomes I G1 , and after being partially reflected by the third fiber Bragg grating of the first probe, a part of the pulse beam is reflected, and its intensity is I G1 r 31 , and the other part of the pulse beam is transmitted through the third fiber Bragg grating, and transmit to the probe through the delayer, its intensity is I G1 t 31 ; where r 31 is the reflectivity of the third fiber grating in the first probe, and the transmitted pulse beam with the intensity of I G1 t 31 passes through the second After the gas in the gas chamber in the probe is absorbed, its intensity becomes I G2 , a part of the pulse beam is reflected, its intensity is I G2 r 31 , and a part of the pulse beam is transmitted, its intensity is I G2 t 31 ; and so on until probe n; 对于探头1光纤光栅3的回波信号IG1’，For the echo signal I G1 ' of probe 1 fiber grating 3, 其中，α1为与第一探头中气室和待测气体特征吸收波长有关的常数，c1为气室内气体的浓度；Wherein, α1 is a constant related to the gas chamber in the first probe and the characteristic absorption wavelength of the gas to be measured, and c1 is the concentration of gas in the gas chamber; 同理，对于探头2光纤光栅3的回波信号IG2’，Similarly, for the echo signal I G2 ' of the probe 2 fiber grating 3, 依次类推，对于回波信号IGn’，And so on, for the echo signal I Gn ', 基于公式(1)-(n)，通过获取的回波信号IG1’、IG2’、……、IGn’，最终可以反演得到各个探头处待测气体的浓度值。Based on the formulas (1)-(n), through the obtained echo signals I G1 ′, I G2 ′, ..., I Gn ′, the concentration values of the gas to be measured at each probe can be finally obtained by inversion.
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