CN110907060A - Fault automatic multiplexing system and method of fiber bragg grating array oil tank fire alarm monitoring system - Google Patents
Fault automatic multiplexing system and method of fiber bragg grating array oil tank fire alarm monitoring system Download PDFInfo
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- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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Abstract
The invention discloses a fault automatic multiplexing system and a fault automatic multiplexing method of a fiber grating array oil tank fire alarm monitoring system, wherein two fiber grating array detection optical cables are laid at the top end of each oil tank to be monitored in the system, and the temperature of the oil tank is monitored in real time through the fiber grating array detection optical cables; the optical switch is used for controlling the on-off of the optical path, and the two fiber bragg grating array detection optical cables connected to each oil tank can realize automatic switching multiplexing through the optical switch; the system comprises a monitoring and measuring host and at least one standby monitoring and measuring host, wherein the monitoring and measuring host and the standby monitoring and measuring host are used for analyzing oil tank temperature signals transmitted by an optical fiber grating array detection optical cable, and the monitoring and measuring host and the standby monitoring and measuring host realize automatic switching multiplexing through an optical switch; the remote terminal monitors the analyzed oil tank temperature information in real time, and sends out an alarm signal when the oil tank temperature exceeds a threshold value. The invention can automatically switch the standby measuring host, realizes seamless monitoring, and has the advantages of low cost, strong operability, risk avoidance and the like.
Description
Technical Field
The invention relates to the technical field of optical fiber sensing, in particular to a fault automatic multiplexing system and method of an optical fiber grating array oil tank fire alarm monitoring system.
Background
The storage tank area is an important task of transferring, storing and transporting in the petrochemical production process, and is an oil product storage base and a supply transfer station. Due to the physical and chemical properties of petroleum products, the storage tank area has a greater risk of fire. For example, the inherent fire hazard of oil products; explosive fire disasters are more, and the fire hazard is large; the spreading speed is high, and the temperature of a fire scene is high; the difficulty of the rescue is high. In recent years, fire accidents of petrochemical enterprises frequently occur, great loss is caused to the enterprises, and great harm is brought to people.
The existing optical fiber sensing technology can realize oil tank fire alarm monitoring, the optical fiber grating array technology can achieve centimeter-level temperature sensing, meter-level space positioning and kilometer-level monitoring range, and can timely and accurately monitor the temperature change of the oil storage tank before a fire disaster occurs and send out early warning. The detection distance of the monitoring system is long, one monitoring host can monitor a plurality of oil tanks at the same time, and if the monitoring host fails or a fiber breaking fault occurs in a detection optical cable in the fire monitoring operation process, the risk that the monitored oil tanks lose protection at the same time exists. Therefore, the technology for automatically switching to the standby system after the monitoring system fails to avoid risks and realize seamless monitoring has important significance, and means that the petroleum storage tank fire monitoring technology enters a full-time and dead-angle-free dual-computer hot standby monitoring mode. A new technical route is provided for safety monitoring of petroleum storage tanks in China, the construction pace of intelligent oil tank fire monitoring is accelerated, the energy safety policy in China is better stabilized, the reuse cost of double-machine hot standby for oil tank fire monitoring is saved, and the method has a very wide market prospect.
Disclosure of Invention
The invention aims to solve the technical problem of providing a fault automatic multiplexing system and a fault automatic multiplexing method of a fiber bragg grating array oil tank fire alarm monitoring system aiming at the defects in the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the invention provides a fault automatic multiplexing system of a fiber grating array oil tank fire alarm monitoring system, which comprises a remote terminal, a fiber grating array oil tank fire monitoring host, an optical switch and a fiber grating array detection optical cable, wherein the system is used for carrying out real-time fire alarm monitoring on an oil tank; wherein:
the oil tank temperature monitoring system comprises fiber grating array detection optical cables, wherein two fiber grating array detection optical cables are laid at the top end of each oil tank to be monitored, and the oil tank temperature is monitored in real time through the fiber grating array detection optical cables;
the optical switch is a multi-channel optical switch and is used for controlling the on-off of the optical path; one end of the optical switch is connected with the fiber bragg grating array oil tank fire monitoring host, the other end of the optical switch is connected with the fiber bragg grating array detection optical cables for monitoring each oil tank, and the two fiber bragg grating array detection optical cables connected to each oil tank can realize automatic switching multiplexing through the optical switch;
the fiber grating array oil tank fire monitoring host comprises a monitoring and measuring host and at least one standby monitoring and measuring host, and is used for analyzing oil tank temperature signals transmitted by a fiber grating array detection optical cable, and the monitoring and measuring host and the standby monitoring and measuring host realize automatic switching multiplexing through an optical switch;
and the remote terminal is remotely connected with the fiber bragg grating array oil tank fire monitoring host through a network, is used for monitoring the analyzed oil tank temperature information in real time, and sends out an alarm signal when the oil tank temperature exceeds a threshold value.
Furthermore, the fiber grating array detection optical cable is a temperature sensing optical cable and is prepared by writing a plurality of gratings with certain intervals on a single-mode fiber.
Furthermore, the photosensitive optical cable of the invention adopts a structure that the light-sensitive characteristic is periodically distributed along the refractive index formed by the axial direction of the fiber core, the wavelength of the reflected light is determined by the grating period, and the method for setting the photosensitive optical cable according to different monitoring environments comprises the following steps:
when the temperature is the only variable, the central wavelength of the fiber grating will shift due to the combined action of the thermal expansion effect, the thermo-optic effect and the elasto-optic effect, and the central wavelength lambda of the gratingBThe variation form is expressed as:
wherein the content of the first and second substances,
representing the thermo-optic coefficient of the fiber grating; (Δ n)eff)epRepresenting the elasto-optic effect caused by thermal expansion;
represents the waveguide effect caused by thermal expansion;
represents the fiber thermal expansion coefficient; further simplification is as follows:
wherein the content of the first and second substances,
is composed of
KwgRepresenting the wavelength drift coefficient, related to the waveguide effect, α is
Neglecting the influence of the waveguide effect on the temperature sensitivity coefficient, the relative temperature sensitivity coefficient KTComprises the following steps:
the temperature sensitivity coefficient is related to the material refractive index and the temperature coefficient, namely, the photosensitive optical cable is set by selecting the material refractive index and the temperature coefficient according to different monitoring environments.
Further, the optical switch of the present invention is an optical switch of M × N channels; the monitoring and measuring host and the standby monitoring and measuring host are connected with one side of the M channel of the optical switch, and can be connected with at most one monitoring and measuring host and M-1 standby monitoring and measuring hosts.
Furthermore, the fiber grating array detection optical cables are connected with one side of the N channels of the optical switch, each fiber grating array detection optical cable is connected with one channel, two fiber grating array detection optical cables monitor one oil tank, and at most N/2 oil tanks can be monitored.
Further, the remote terminal of the present invention includes a computer, a mobile phone or a mobile tablet.
The invention provides a fault automatic multiplexing method of a fiber grating array oil tank fire alarm monitoring system, which comprises the following steps:
when the system normally operates, the standby monitoring and measuring host and an optical channel of a fiber bragg grating array detection optical cable on the oil tank are in a disconnected state;
when monitoring the optical path fault of the monitoring and measuring host, the optical switch automatically switches the optical path channel of the monitoring and measuring host to a standby monitoring and measuring host;
when the fiber breakage fault of the fiber bragg grating array detection optical cable of a certain oil tank is monitored, the optical path channel of the optical cable is automatically switched to the other fiber bragg grating array detection optical cable channel of the same oil tank, and therefore automatic switching and multiplexing of the fire alarm monitoring system can be achieved when the host machine is monitored to be in fault or the optical cable is broken.
Further, the method for preparing the fiber grating array detection optical cable for monitoring the temperature of the oil tank comprises the following steps: a temperature sensing optical cable is formed by writing a plurality of gratings with certain intervals on a single optical fiber; the method for setting the optical switch comprises the following steps: the optical switch of the MXN channel is arranged on the optical path fault of the fiber grating array oil tank fire monitoring host or the fiber grating array detection optical cable is broken through communication, so that the functions of disconnecting and switching the optical path channel are realized.
Further, the method for demodulating the center wavelength of the fiber grating of the present invention comprises:
processing the collected data by adopting a Gaussian fitting algorithm, and performing Gaussian curve fitting on a spectrum curve of the data, wherein the fiber grating reflection spectrum curve is as follows:
wherein, I0Representing the intensity of the reflected spectrum, λBRepresenting the central wavelength of the Bragg grating, Delta lambdaBRepresents the 3dB bandwidth of the reflection spectrum; taking logarithm of two sides of the formula to obtain:
let P (λ) be lnI (λ),
obtaining:
P(λ)＝Aλ2+Bλ+C
assuming that N sets of data points are collected, the coordinates of each set of data points is P (λ) ═ a λ2+Bλ+C，P(λ)＝Aλ2+ B λ + C; the square sum S of the error between the actual value and the calculated value is obtained by a least square method and is as follows:
when S takes the minimum value, solving to obtain corresponding A/B/C, so that the central wavelength of the fiber grating reflection spectrum is as follows:
the invention has the following beneficial effects: the fault automatic multiplexing system and the fault automatic multiplexing method of the fiber bragg grating array oil tank fire alarm monitoring system are suitable for being applied to the fiber bragg grating array oil tank fire alarm monitoring system, system fault automatic switching multiplexing is achieved by using the optical switch device with the on-off function, blank monitoring risks caused by faults are effectively avoided, and the system and the method have the advantages of low cost, strong operability, risk avoidance and the like.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic diagram of the normal operation of a fiber grating array oil tank fire alarm monitoring system;
FIG. 2 is a schematic diagram of the operation of a backup detection cable of the fiber grating array oil tank fire alarm monitoring system;
fig. 3 is a working schematic diagram of a standby monitoring host of the fiber bragg grating array oil tank fire alarm monitoring system.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1, the fault automatic multiplexing system of the fiber grating array oil tank fire alarm monitoring system according to the embodiment of the present invention includes a remote terminal, a fiber grating array oil tank fire monitoring host, an optical switch, and a fiber grating array detection optical cable, and performs real-time fire alarm monitoring on an oil tank through the system; wherein:
the oil tank temperature monitoring system comprises fiber grating array detection optical cables, wherein two fiber grating array detection optical cables are laid at the top end of each oil tank to be monitored, and the oil tank temperature is monitored in real time through the fiber grating array detection optical cables;
the optical switch is a multi-channel optical switch and is used for controlling the on-off of the optical path; one end of the optical switch is connected with the fiber bragg grating array oil tank fire monitoring host, the other end of the optical switch is connected with the fiber bragg grating array detection optical cables for monitoring each oil tank, and the two fiber bragg grating array detection optical cables connected to each oil tank can realize automatic switching multiplexing through the optical switch;
the fiber grating array oil tank fire monitoring host comprises a monitoring and measuring host and at least one standby monitoring and measuring host, and is used for analyzing oil tank temperature signals transmitted by a fiber grating array detection optical cable, and the monitoring and measuring host and the standby monitoring and measuring host realize automatic switching multiplexing through an optical switch;
and the remote terminal is remotely connected with the fiber bragg grating array oil tank fire monitoring host through a network, is used for monitoring the analyzed oil tank temperature information in real time, and sends out an alarm signal when the oil tank temperature exceeds a threshold value.
The fiber grating array detection optical cable is a temperature sensing optical cable and is prepared by writing a plurality of gratings with certain intervals on a single-mode optical fiber.
The optical switch is an optical switch with M multiplied by N channels; the monitoring and measuring host and the standby monitoring and measuring host are connected with one side of the M channel of the optical switch, and can be connected with at most one monitoring and measuring host and M-1 standby monitoring and measuring hosts. The fiber grating array detection optical cables are connected with one side of the N channel of the optical switch, each fiber grating array detection optical cable is connected with one channel, and the two fiber grating array detection optical cables monitor one oil tank and can monitor N/2 oil tanks at most.
The fault automatic multiplexing method of the fiber bragg grating array oil tank fire alarm monitoring system comprises the following steps:
the method comprises the following steps that (1) the detection optical cables are laid at the top ends of the oil tanks, a combination of two detection optical cables is laid according to one oil tank, the two detection optical cables are respectively connected to channels of the optical switch, the two channels are occupied and marked as a channel 1 and a channel 16, the detection optical cables of the channel 16 are set as standby detection optical cables, and the number of the detection optical cables can be expanded according to the monitoring maximum range of a monitoring host.
And (2) respectively connecting one channel of the two monitoring and measuring hosts to the optical switch channel by using optical fibers, occupying the two channels, recording as the channel No. 1 and the channel No. 16, and setting the monitoring and measuring host of the channel No. 16 as a standby measuring host. And the monitoring and measuring host is connected with the computer through a network.
And (3) starting a computer, monitoring the measuring host and the optical switch, and automatically controlling the on-off of the optical path by the optical switch. When the fiber grating array oil tank fire alarm monitoring system normally operates, the number 16' channel of the standby monitoring host and the number 16 channel of the standby detection cable on the oil tank are in a disconnected state, the optical module part of the monitoring and measuring host emits light signals, and a plurality of grating sensors are distributed on the detection optical cable.
The sensor is a fiber grating array sensor, the fiber grating is a structure with refractive index periodically distributed along the axial direction of a fiber core by using the natural photosensitive characteristic of a fiber material, and the wavelength of reflected light is determined by the grating period, namely, gratings with different periods are manufactured and different wavelengths can be reflected. Wherein the central wavelength of the grating is:
λB＝2neffΛ (1-1)
when the temperature is the only variable, the central wavelength of the fiber grating will shift due to the combined action of the thermal expansion effect, the thermo-optic effect and the elasto-optic effect, and the variation form is shown as follows:
wherein the content of the first and second substances,
representing the thermo-optic coefficient of the fiber grating; (Δ n)eff)epRepresenting the elasto-optic effect caused by thermal expansion;
represents the waveguide effect caused by thermal expansion;
representing the fiber thermal expansion coefficient. Further simplification can be achieved:
wherein the content of the first and second substances,
is composed of
KwgRepresenting the wavelength drift coefficient, related to the waveguide effect, α is
Since the effect of the waveguide effect on the temperature coefficient of sensitivity is very small, the corresponding effect of the waveguide is negligible in the calculation. Thus, it can be seen that:
KTrepresenting the relative temperature sensitivity coefficient. When the influence of external factors is neglected, the temperature sensitivity coefficient is mainly related to the refractive index and the temperature coefficient of the material.
The monitoring host system adopts a tunable narrow-band light source demodulation method to use a tunable laser as a light source, the output wavelength of the tunable narrow-band laser is related to the driving current, and the periodic scanning of the output wavelength of the laser can be realized by controlling the driving current of the laser. When the wavelength output by the tunable narrow-band laser is matched with the central wavelength of the grating to be detected, the reflected light intensity received by the photoelectric detection module is the maximum, and the received analog electric signal is sampled and subjected to data processing by the data processing module, so that the central wavelength of the fiber grating can be finally demodulated.
The spectrum shape of the fiber grating reflection spectrum is very similar to a Gaussian function curve, collected data are processed by adopting a Gaussian fitting algorithm, the Gaussian curve fitting is carried out on the spectrum curve, and the reflection spectrum peak position can be obtained through the corresponding Gaussian function. The classical formula of the gaussian function is:
thus, the fiber grating reflectance spectrum curve can be expressed as:
I0representing the intensity of the reflected spectrum, λBRepresenting the central wavelength of the non-Bragg grating, Delta lambdaBRepresenting the 3dB bandwidth of the reflectance spectrum, the logarithm is taken on both sides of the formula:
let P (λ) be lnI (λ),
the following can be obtained:
P(λ)＝Aλ2+Bλ+C (1-8)
the equations (1-8) are typical forms of a quadratic polynomial fit, assuming that N sets of data points are collected,the coordinates of each set of data points are P (λ) ═ a λ2+Bλ+C，P(λ)＝Aλ2+ B λ + C. The square sum S of the error between the actual value and the calculated value of the formula (1-8) obtained by the least square method is:
when S takes the minimum value, the corresponding A/B/C can be obtained by solving, so that the central wavelength of the fiber grating reflection spectrum is as follows:
the fire monitoring system with the fiber bragg grating array can realize that one optical cable monitors the whole oil tank, and can realize automatic multiplexing and switching by monitoring the reflected optical signals through the monitoring host system. When the monitoring host optical path system fails, the system can automatically switch and multiplex the optical path channel to the standby host channel because the optical signal cannot be received, at the moment, the channel 1 of the measuring host is disconnected, and the channel 16 of the standby detection cable is opened; when the fiber grating array optical cable has a fiber breaking fault, the system monitors that only part of reflected light wavelength signals exist, the system can automatically switch and multiplex the optical path channel to the standby optical cable channel, the No. 1 optical cable channel is in a disconnected state, and the No. 16 detection optical cable is in an open state, so that the automatic switching and multiplexing of the fire alarm monitoring system can be realized when a monitoring host machine fails or the optical cable breaks.
The invention is mainly suitable for the application of a fiber grating array oil tank fire monitoring and alarming system, realizes the automatic switching and multiplexing of system faults by utilizing the optical switch device with the on-off function, effectively avoids blank monitoring risks caused by faults, and has the advantages of low cost, strong operability, risk avoidance and the like.
It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.
Claims (9)
1. A fault automatic multiplexing system of a fiber grating array oil tank fire alarm monitoring system is characterized in that the system comprises a remote terminal, a fiber grating array oil tank fire monitoring host, an optical switch and a fiber grating array detection optical cable, and the system is used for carrying out real-time fire alarm monitoring on an oil tank; wherein:
the oil tank temperature monitoring system comprises fiber grating array detection optical cables, wherein two fiber grating array detection optical cables are laid at the top end of each oil tank to be monitored, and the oil tank temperature is monitored in real time through the fiber grating array detection optical cables;
the optical switch is a multi-channel optical switch and is used for controlling the on-off of the optical path; one end of the optical switch is connected with the fiber bragg grating array oil tank fire monitoring host, the other end of the optical switch is connected with the fiber bragg grating array detection optical cables for monitoring each oil tank, and the two fiber bragg grating array detection optical cables connected to each oil tank can realize automatic switching multiplexing through the optical switch;
the fiber grating array oil tank fire monitoring host comprises a monitoring and measuring host and at least one standby monitoring and measuring host, and is used for analyzing oil tank temperature signals transmitted by a fiber grating array detection optical cable, and the monitoring and measuring host and the standby monitoring and measuring host realize automatic switching multiplexing through an optical switch;
and the remote terminal is remotely connected with the fiber bragg grating array oil tank fire monitoring host through a network, is used for monitoring the analyzed oil tank temperature information in real time, and sends out an alarm signal when the oil tank temperature exceeds a threshold value.
2. The automatic fault multiplexing system of the fiber bragg grating array oil tank fire alarm monitoring system according to claim 1, wherein the fiber bragg grating array detection optical cable is a temperature sensing optical cable and is prepared by writing a plurality of gratings with certain intervals on a single-mode optical fiber.
3. The automatic multiplexing system of the failure of the fire alarm monitoring system for the oil tank with the fiber bragg grating array as claimed in claim 2, wherein the photosensitive optical cable is of a structure with a light-sensitive characteristic in which refractive indexes are periodically distributed along the axial direction of a fiber core, the wavelength of reflected light is determined by the period of the grating, and the method for arranging the photosensitive optical cable according to different monitoring environments comprises the following steps:
when the temperature is the only variable, the central wavelength of the fiber grating will shift due to the combined action of the thermal expansion effect, the thermo-optic effect and the elasto-optic effect, and the central wavelength lambda of the gratingBThe variation form is expressed as:
wherein the content of the first and second substances,
representing the thermo-optic coefficient of the fiber grating; (Δ n)eff)epRepresenting the elasto-optic effect caused by thermal expansion;
represents the waveguide effect caused by thermal expansion;
represents the fiber thermal expansion coefficient; further simplification is as follows:
wherein the content of the first and second substances,
is composed of
KwgRepresenting the wavelength drift coefficient, related to the waveguide effect, α is
Neglecting the influence of the waveguide effect on the temperature sensitivity coefficient, the relative temperature sensitivity coefficient KTComprises the following steps:
the temperature sensitivity coefficient is related to the material refractive index and the temperature coefficient, namely, the photosensitive optical cable is set by selecting the material refractive index and the temperature coefficient according to different monitoring environments.
4. The fiber grating array fire alarm monitoring system failure automatic multiplexing system of claim 1, wherein the optical switch is an M x N channel optical switch; the monitoring and measuring host and the standby monitoring and measuring host are connected with one side of the M channel of the optical switch, and can be connected with at most one monitoring and measuring host and M-1 standby monitoring and measuring hosts.
5. The fiber grating array fire alarm monitoring system fault automatic multiplexing system of claim 4, wherein the fiber grating array detection optical cables are connected with one side of N channels of the optical switch, each fiber grating array detection optical cable is connected with one channel, two fiber grating array detection optical cables monitor one oil tank, and at most N/2 oil tanks can be monitored.
6. The fiber grating array fire alarm monitoring system fault automatic multiplexing system of claim 1, wherein the remote terminal comprises a computer, a mobile phone or a mobile tablet.
7. A method for automatically multiplexing the faults of a fiber grating array fire alarm monitoring system for an oil tank, which adopts the system for automatically multiplexing the faults of the fiber grating array fire alarm monitoring system for the oil tank as claimed in claim 1, and is characterized by comprising the following steps:
step 1, setting a remote terminal, a plurality of fiber bragg grating array oil tank fire monitoring hosts and an optical switch of an MXN channel; preparing a fiber bragg grating array detection optical cable for monitoring the temperature of the oil tank;
step 2, selecting one fiber bragg grating array oil tank fire monitoring host as a monitoring and measuring host, and connecting the rest of the fiber bragg grating array oil tank fire monitoring hosts as standby monitoring and measuring hosts with a remote terminal through a network; the fiber grating array oil tank fire monitoring host is respectively connected with each channel at one end of the optical switch, two fiber grating array detection optical cables are laid on the top of each oil tank, and each fiber grating array detection optical cable is respectively connected with each channel at the other end of the optical switch;
step 3, starting the remote terminal, the fiber grating array oil tank fire monitoring host and the optical switch, controlling the on-off of the optical path by the optical switch, acquiring and processing reflected light signals by the fiber grating array oil tank fire monitoring host, demodulating to obtain the central wavelength of the fiber grating, and monitoring the temperature information of the oil tank by monitoring the central wavelength of the fiber grating in real time;
when the system normally operates, the standby monitoring and measuring host and an optical channel of a fiber bragg grating array detection optical cable on the oil tank are in a disconnected state;
when monitoring the optical path fault of the monitoring and measuring host, the optical switch automatically switches the optical path channel of the monitoring and measuring host to a standby monitoring and measuring host;
when the fiber breakage fault of the fiber bragg grating array detection optical cable of a certain oil tank is monitored, the optical path channel of the optical cable is automatically switched to the other fiber bragg grating array detection optical cable channel of the same oil tank, and therefore automatic switching and multiplexing of the fire alarm monitoring system can be achieved when the host machine is monitored to be in fault or the optical cable is broken.
8. The method for automatically multiplexing faults of the fiber grating array oil tank fire alarm monitoring system according to claim 7, wherein the method for preparing the fiber grating array detection optical cable for monitoring the temperature of the oil tank comprises the following steps: a temperature sensing optical cable is formed by writing a plurality of gratings with certain intervals on a single optical fiber; the method for setting the optical switch comprises the following steps: the optical switch of the MXN channel is arranged on the optical path fault of the fiber grating array oil tank fire monitoring host or the fiber grating array detection optical cable is broken through communication, so that the functions of disconnecting and switching the optical path channel are realized.
9. The method for automatically multiplexing faults of the fiber grating array oil tank fire alarm monitoring system according to claim 7, wherein the method for demodulating the central wavelength of the fiber grating is as follows:
processing the collected data by adopting a Gaussian fitting algorithm, and performing Gaussian curve fitting on a spectrum curve of the data, wherein the fiber grating reflection spectrum curve is as follows:
wherein, I0Representing the intensity of the reflected spectrum, λBRepresenting the central wavelength of the Bragg grating, Delta lambdaBRepresents the 3dB bandwidth of the reflection spectrum; taking logarithm of two sides of the formula to obtain:
let P (λ) be ln I (λ),
obtaining:
P(λ)＝Aλ2+Bλ+C
assuming that N sets of data points are collected, the coordinates of each set of data points is P (λ) ═ a λ2+Bλ+C，P(λ)＝Aλ2+ B λ + C; the square sum S of the error between the actual value and the calculated value is obtained by a least square method and is as follows:
when S takes the minimum value, solving to obtain corresponding A/B/C, so that the central wavelength of the fiber grating reflection spectrum is as follows:
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201266418Y (en) * | 2008-07-25 | 2009-07-01 | 中国计量学院 | On-line real time fibre-optical grating fire monitoring system |
| CN102607737A (en) * | 2012-02-17 | 2012-07-25 | 山东大学 | Device for monitoring temperature of oil tank by FBG (Fiber Bragg Grating) |
| CN202547822U (en) * | 2012-02-17 | 2012-11-21 | 山东大学 | Device using fiber bragg grating to monitor oil tank temperature |
| JP2015031594A (en) * | 2013-08-02 | 2015-02-16 | アンリツ株式会社 | Multichannel fbg sensor monitor system and multichannel fbg sensor monitor method |
| CN205759333U (en) * | 2016-05-18 | 2016-12-07 | 淄博国脉通信工程有限公司 | Tank fire warning system based on Fibre Optical Sensor |
-
2019
- 2019-11-29 CN CN201911200179.4A patent/CN110907060A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201266418Y (en) * | 2008-07-25 | 2009-07-01 | 中国计量学院 | On-line real time fibre-optical grating fire monitoring system |
| CN102607737A (en) * | 2012-02-17 | 2012-07-25 | 山东大学 | Device for monitoring temperature of oil tank by FBG (Fiber Bragg Grating) |
| CN202547822U (en) * | 2012-02-17 | 2012-11-21 | 山东大学 | Device using fiber bragg grating to monitor oil tank temperature |
| JP2015031594A (en) * | 2013-08-02 | 2015-02-16 | アンリツ株式会社 | Multichannel fbg sensor monitor system and multichannel fbg sensor monitor method |
| CN205759333U (en) * | 2016-05-18 | 2016-12-07 | 淄博国脉通信工程有限公司 | Tank fire warning system based on Fibre Optical Sensor |
Non-Patent Citations (2)
| Title |
|---|
| 吴付岗等: "光纤光栅Bragg波长的高斯曲线拟合求法", 《武汉理工大学学报》 * |
| 贾振安等: "光纤光栅温度灵敏度系数研究", 《光电子·激光》 * |
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