CN201926524U - Fiber Bragg grating temperature measuring system and multipoint temperature measuring system - Google Patents
Fiber Bragg grating temperature measuring system and multipoint temperature measuring system Download PDFInfo
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- CN201926524U CN201926524U CN2009202219732U CN200920221973U CN201926524U CN 201926524 U CN201926524 U CN 201926524U CN 2009202219732 U CN2009202219732 U CN 2009202219732U CN 200920221973 U CN200920221973 U CN 200920221973U CN 201926524 U CN201926524 U CN 201926524U
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Abstract
The utility model relates to a fiber Bragg grating temperature measuring system, which belongs to the field of temperature measuring and comprises a temperature measuring sensing head and an FBG (fiber Bragg grating) temperature measuring control instrument. Broad-spectrum light emitted from an SLED (superluminescent light emitting diode) light source of the FBG temperature measuring control instrument enters the temperature measuring sensing head after passing through a first fiber directional coupler, and the period is changed since the temperature measuring sensing head is changed due to external temperature change and further the center wavelength is changed. The light emitted from the broad-spectrum SLED light source is changed into a narrow-band signal with the center wavelength corresponding to the center wavelength of the sensing head after being reflected by the temperature measuring sensing head, and the narrow-band signal enters a temperature discriminator after passing through the first directional coupler and a second directional coupler sequentially. The utility model simultaneously provides a multipoint temperature measuring system realized by the aid of the fiber Bragg grating temperature measuring system. By organically combining the automatic temperature control technology with the fiber Bragg grating technology, instability of a common fiber Bragg grating temperature measuring system in series connection is improved and cost is reduced. The utility model further provides a simplified fiber Bragg grating temperature measuring structure, so that complexity of the system is decreased and cost is further reduced.
Description
Technical field
The utility model relates to the temperature monitoring system based on fiber grating, belongs to field of sensing technologies.
Background technology
In electric system, in the equipment long-time running process, positions such as various disconnecting links contact and bus row junction are because of wearing out or contact resistance is excessive generates heat.By the ruuning situation of monitoring contact temperature, can prevent effectively that the fire of power equipment from taking place, realize that therefore on-line temperature monitoring is the important means that guarantees the power equipment safety operation.Because the environment of power equipment high pressure causes the temperature of these heating positions to be difficult to timely on-line monitoring, therefore causes fire failure easily.At present, domestic most of power plant and transformer station adopt the temp measuring system based on electric signal sensor.Wherein infrared measurement of temperature is a non-cpntact measurement, is subject to environment and peripheral electromagnetic field and disturbs, and need manually-operated, can't realize on-line measurement, inefficiency; Electronic temperature transmitter is subject to electromagnetic interference (EMI), and the temperature sensor of machinery is subjected to the influence of environment also bigger, more than the measurement effect of several detection methods all not ideal enough.Therefore develop a kind of large-capacity distributing online in real time temperature monitoring system, the temperature of monitoring various power equipments contact has become the power industry task of top priority.
Along with the development of sensor technology, signal processing technology, computer technology, artificial intelligence technology, make that the state of temperature to each equipment of transformer station carries out on-line monitoring, in time finding potential faults and accumulative total property fault made prediction becomes possibility.It reduces maintenance frequency for the normal operation that guarantees substation equipment, and the operational reliability and the automaticity that improve electric system are significant.Because high voltage electric power equip ment is in high voltage, high-temperature, high-intensity magnetic field and the extremely strong electromagnetic interference environment, realize the thermometric to contact, must solve the adaptability of electronic measuring device under above-mentioned severe environmental conditions.
Utilize optical fiber grating temperature-measuring to be mostly to adopt the wavelength selectivity reflection original of FBG: when composite signal entered FBG, near the spectrum its reflection kernel wavelength almost all was reflected back, but not near the almost completely transmission of light the centre wavelength.The existing scheme of optical fiber grating temperature-measuring of utilizing is utilized the thermally sensitive characteristic of fiber grating, the wavelength that utilizes broadband spectral to enter behind the grating selects reflection characteristic to carry out the measurement of temperature, thereby reflection wave is introduced the fiber grating demodulation device wavelength is carried out demodulation, obtain temperature to be measured.Because the fiber grating demodulation device costs an arm and a leg, the general mode that adopts a plurality of fiber gratings to connect of this scheme realizes the measurement of multiple spot.The cost of each measurement point can be shared equally like this.Though this scheme has realized utilizing fiber grating that temperature is measured, because grating is connected, therefore in case wherein certain is damaged, total system just can not have been worked, and has reduced the stability of system.
The utility model patent content
The utility model at above-mentioned prior art and deficiency, the utility model provides two kinds of novel optical fiber and optical grating temp measuring systems with identical utility model design, and provide two kinds of multi-point temperature measurement systems that utilize these two kinds of temp measuring systems to realize respectively, utilize the FBG that is with heat-conducting plate to make the temperature Discr. measured temperature is differentiated, improved measuring accuracy greatly.And overcome, and, employing greatly reduces cost owing to oneself having designed FBG thermometric controller owing to series connection has caused systematic jitters.
A kind of fiber grating temperature sensor of the present utility model system, comprise thermometric sensing head and FBG thermometric controller, it is characterized in that FBG thermometric controller comprises temperature Discr., wide range SLED light source, first fiber directional coupler, second fiber directional coupler, photo-detector and the CPU that is with heat-conducting plate; The wide range light of SLED light emitted is by entering the thermometric sensing head after first fiber directional coupler, described thermometric sensing head is subjected to the variation of external temperature and change cycle and then change centre wavelength, the light that is sent by wide range SLED light source becomes the centre wavelength narrow band signal corresponding with sensing head centre wavelength after the reflection of thermometric sensing head, this narrow band signal is successively by entering the temperature Discr. behind first direction coupling mechanism and the second direction coupling mechanism; The centre wavelength of temperature Discr. is according to the heating or the cooling temperature change of heat-conducting plate, the narrow band signal that enters temperature Discr. reflected signal when identical with the centre wavelength of temperature Discr. is the strongest, reflected signal is admitted to photo-detector via the second direction coupling mechanism, light signal strength by the photo-detector collection is admitted to CPU, and CPU is according to the light signal strength maximum value calculation and monitor external temperature.
As preferred implementation, described system can also comprise another photo-detector of baseline optical signal being sent into CPU.
The another kind of fiber grating temperature sensor system that the utility model provides, comprise the thermometric sensing head that places external environment condition, stick to narrow-band semiconductor laser instrument, directional coupler, photo-detector and CPU on the heat-conducting plate, described thermometric sensing head is subjected to the variation of external temperature and changes centre wavelength; Heat or lower the temperature by CPU control heat-conducting plate noise spectra of semiconductor lasers, its center emission wavelength is changed; The narrow band light of semiconductor laser emission enters the thermometric sensing head, is admitted to photo-detector through directional coupler after the narrow band light that is complementary with thermometric sensing head centre wavelength is reflected, and the signal of photo-detector output is admitted to CPU; The CPU internal memory contains the calibration data of expressing the relation between narrow-band semiconductor laser instrument emission wavelength and the external temperature, and CPU calculates external temperature according to the signal and the calibration data of photo-detector input.
The utility model provides the multi-point temperature measurement system that utilizes above-mentioned fiber grating temperature sensor system to realize respectively simultaneously, use a photoswitch with two or more optical fiber grating temperature-measuring system parallel connections, by the temperature patrol inspection of time division multiplex realization to a plurality of points.
The utility model organically combines temperature automatic control technology and fiber grating, has given full play to the advantage of fiber grating, has improved the instability of general tandem type optical fiber grating temperature-measuring system, and has reduced cost, and the precision height of thermometric uses flexibly.The utility model has also proposed a kind of parallel optical fibre grating thermometric structure that adopts photoswitch, can further reduce cost.Particularly, the utlity model has following advantage:
1. high temperature resistant, measuring temperature range is 0 ℃～250 ℃;
2. measuring accuracy height, error generally+/-0.1 ℃;
3. reliability height, the up time was more than 20 years;
4. cost is low, and general one cost is about 3000 yuan;
5. volume is little, is convenient to install, and package dimension is Φ 5.5 * 65mm;
6. each probe works alone during many parallel connections, can not influence each other;
7. full quartz packaged, the insulativity height.
Description of drawings
Accompanying drawing 1 is a theory structure synoptic diagram of the present utility model;
The optical fiber grating temperature-measuring structural representation of accompanying drawing 2 for simplifying.
Embodiment
Specify below in conjunction with schematic diagram of the present utility model:
As shown in Figure 1, the utility model comprises thermometric sensing head 1, and this two large divisions of FBG thermometric controller.And comprised 3, two fiber directional couplers 4 of wide range SLED light source and 5 in the FBG thermometric controller, temperature Discr. 6,7, two photodetection instrument 8 of heat-conducting plate and 9, and the CPU 10 of a control usefulness.Temperature Discr. 6 be stick on the heat-conducting plate 7 so that change the grating cycle and the centre wavelength of temperature Discr. 6 by heat-conducting plate 7 heating or cooling.CPU10 and heat-conducting plate 7, two photo-detectors 8 link to each other with 9 and SLED light source 3, control the running of whole FBG thermometric controller.
As Fig. 1, thermometric sensing head 1 is placed external environment condition, thereby change the centre wavelength that its reflects because the temperature of external environment condition can cause the grating cycle of thermometric sensing head to change.SLED light source 3 from the thermometric controller enters the thermometric sensing head after emitting wide range light direction of passage coupling mechanism 4, the thermometric sensing head of this moment has been because because external temperature has changed the cycle, so wide range light enters the information that narrow band light that the sensing head back reflection returns has just been carried external temperature.Owing to plated absorbing film in thermometric sensing head 1 other end, so the signal that sensing head 1 is crossed in transmission will be absorbed, can be because of reflection taking place and influence measurement afterwards at rear end face.Reflected narrow band light by entering temperature Discr. 6 after fiber directional coupler 4 and 5 by thermometric sensing head 1, CPU control this moment heat-conducting plate 7 is given 6 heating of temperature Discr. or cooling, monitors the luminous power of accepting on photo- detector 8 and 9 simultaneously.Heat-conducting plate 7 heating or cooling make the temperature of the temperature Discr. 6 on it rise or reduce, thereby the feasible wherein cyclomorphosis of FBG changes its reflection kernel wavelength.When its heating or the cooling temperature not to the time, the centre wavelength of temperature Discr. 6 does not match with the narrow band light that has the external temperature signal of transmitting the temperature Discr., thereby causes the most of transmission excess temperature of laser of narrowband Discr. 6 to enter photo-detector 9 and the received optical power of photo-detector 8 almost is very much 0.And when the temperature of heat-conducting plate 7 heating or cooling just in time reaches external temperature, the centre wavelength of temperature Discr. 6 is just in time mated with the narrow band light that has the external temperature signal that transmits the temperature Discr., thereby make the laser of narrowband major part by 6 reflections of temperature Discr., enter photo-detector 8 after the reflected light direction of passage coupling mechanism 5, when the received optical power of photo-detector 8 reaches maximum at this moment, control circuit stops heat-conducting plate being heated or lowers the temperature, and with the heat-conducting plate temperature that the records this moment temperature as sensing head.Meanwhile, all the time the light signal of surveying on the photo-detector 9 be can be used as reference, eliminate any interference that causes because of other factors of system automatically.
As want to measure the temperature of many places, and can use photoswitch with a plurality of such optical fiber grating temperature-measuring system parallel connections, can realize the temperature of a plurality of points is patrolled and examined by time division multiplex.Can also further reduce the cost of each point for measuring temperature like this.
As another alternative embodiment, the utility model also proposes a kind of optical fiber grating temperature-measuring structure of simplification.
As shown in Figure 2, this simplified structure has comprised the CPU 26 of 24, one photo-detectors 25 of 23, heat-conducting plates of 22, one directional couplers of 21, one narrow-band semiconductor laser instruments of thermometric sensing head and a control usefulness.Semiconductor laser 22 sticks on the heat-conducting plate 24, and CPU26 and narrow-band semiconductor laser instrument 22, heat-conducting plate 24, and photo-detector 25 is continuous, with the control whole system operation.
As Fig. 2, the advanced behaviour earlier calibrated before measurement, obtains the relation between narrow-band semiconductor laser instrument emission wavelength and the external temperature.Thermometric sensing head 21 places external environment condition, thereby changes the centre wavelength that its reflects because the temperature of external environment condition can cause the grating cycle of thermometric sensing head to change.Heat-conducting plate 24 and semiconductor laser 22 adhere to each other, heat or lower the temperature by CPU 26 control heat-conducting plates 24 noise spectra of semiconductor lasers 22, and the emission center wavelength temperature influence of semiconductor laser 22, the heating of 24 pairs of laser instruments of heat-conducting plate or cooling can cause the center emission wavelength of semiconductor laser to change.Carry out cyclical variation by CPU26 control heat-conducting plate 24 temperature, thereby make the periodic scan variations of centre wavelength of narrow-band semiconductor laser instrument 22.The laser of narrowband of semiconductor laser 22 emissions enters thermometric sensing head 21, if the narrow band light of emission and the centre wavelength of thermometric sensing head 21 do not match, laser of narrowband is most of so can see through thermometric FBG, because coated absorbing film at thermometric sensing head 21 rear end faces, the narrow band light that sees through thermometric sensing head 21 can be absorbed film and absorb, and does not influence measurement effect and can not reflect.Therefore the luminous power that this moment, photo-detector 25 recorded is very little.And if the centre wavelength of the narrow band light of laser instrument emission and thermometric sensing head 21 is mated, narrow band light is most of so can be entered photo-detector 25 by fiber directional coupler 23 by 21 reflections of thermometric sensing head, and the luminous power maximum that this moment, photo-detector 25 recorded.Control by CPU can record the temperature of the luminous power that records on the photo-detector 25 heat-conducting plate 24 when maximum and the emission center wavelength of semiconductor laser 22.Utilize the data of calibration in advance, CPU 26 can calculate outside temperature this moment.
As want to measure the temperature of many places, and can make equally to use up and open the light a plurality of such optical fiber grating temperature-measuring system parallel connections, can realize the temperature of a plurality of points is patrolled and examined by time division multiplex.Can also further reduce the cost of each point for measuring temperature like this.
Claims (5)
1. optical fiber grating temperature-measuring system, comprise thermometric sensing head and FBG thermometric controller, it is characterized in that FBG thermometric controller comprises temperature Discr., wide range SLED light source, first fiber directional coupler, second fiber directional coupler, photo-detector and the CPU that is with heat-conducting plate; The wide range light of SLED light emitted is by entering the thermometric sensing head after first fiber directional coupler, described thermometric sensing head is subjected to the variation of external temperature and change cycle and then change centre wavelength, the light that is sent by wide range SLED light source becomes the centre wavelength narrow band signal corresponding with sensing head centre wavelength after the reflection of thermometric sensing head, this narrow band signal is successively by entering the temperature Discr. behind first direction coupling mechanism and the second direction coupling mechanism; The centre wavelength of temperature Discr. is according to the heating or the cooling temperature change of heat-conducting plate, the narrow band signal that enters temperature Discr. reflected signal when identical with the centre wavelength of temperature Discr. is the strongest, reflected signal is admitted to photo-detector via the second direction coupling mechanism, light signal strength by the photo-detector collection is admitted to CPU, and CPU is according to the light signal strength maximum value calculation and monitor external temperature.
2. optical fiber grating temperature-measuring system according to claim 1 is characterized in that, described system also comprises another photo-detector of baseline optical signal being sent into CPU.
3. multi-point temperature measurement system that adopts the described optical fiber grating temperature-measuring system of claim 1 to realize, it is characterized in that, use a photoswitch with two or more optical fiber grating temperature-measuring system parallel connections, by the temperature patrol inspection of time division multiplex realization to a plurality of points.
4. optical fiber grating temperature-measuring system, comprise the thermometric sensing head that places external environment condition, stick to narrow-band semiconductor laser instrument, directional coupler, photo-detector and CPU on the heat-conducting plate, described thermometric sensing head is subjected to the variation of external temperature and changes centre wavelength; Heat or lower the temperature by CPU control heat-conducting plate noise spectra of semiconductor lasers, its center emission wavelength is changed; The narrow band light of semiconductor laser emission enters the thermometric sensing head, is admitted to photo-detector through directional coupler after the narrow band light that is complementary with thermometric sensing head centre wavelength is reflected, and the signal of photo-detector output is admitted to CPU; The CPU internal memory contains the calibration data of expressing the relation between narrow-band semiconductor laser instrument emission wavelength and the external temperature, and CPU calculates external temperature according to the signal and the calibration data of photo-detector input.
5. multi-point temperature measurement system that adopts the described optical fiber grating temperature-measuring system of claim 4 to realize, it is characterized in that, use a photoswitch with two or more optical fiber grating temperature-measuring system parallel connections, by the temperature patrol inspection of time division multiplex realization to a plurality of points.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009202219732U CN201926524U (en) | 2009-11-06 | 2009-11-06 | Fiber Bragg grating temperature measuring system and multipoint temperature measuring system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009202219732U CN201926524U (en) | 2009-11-06 | 2009-11-06 | Fiber Bragg grating temperature measuring system and multipoint temperature measuring system |
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| CN201926524U true CN201926524U (en) | 2011-08-10 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102494801A (en) * | 2011-12-07 | 2012-06-13 | 电子科技大学 | Distributed optical delay optical fiber temperature sensor |
| WO2019000969A1 (en) * | 2017-06-30 | 2019-01-03 | 华中科技大学 | Time-division multiplexing closed-loop feedback thermal control method and system |
-
2009
- 2009-11-06 CN CN2009202219732U patent/CN201926524U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102494801A (en) * | 2011-12-07 | 2012-06-13 | 电子科技大学 | Distributed optical delay optical fiber temperature sensor |
| WO2019000969A1 (en) * | 2017-06-30 | 2019-01-03 | 华中科技大学 | Time-division multiplexing closed-loop feedback thermal control method and system |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110810 Termination date: 20181106 |
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| CF01 | Termination of patent right due to non-payment of annual fee |