CN213781166U - Novel cable pit fire early warning real-time monitoring system - Google Patents
Novel cable pit fire early warning real-time monitoring system Download PDFInfo
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Abstract
The utility model discloses a novel cable pit conflagration early warning real-time monitoring system, include: the device comprises a light source module, an optical fiber coupler, an optical fiber circulator, a sensing optical cable, a photoelectric detection module, a data acquisition module and a computer processing module; the light source module comprises an FVS light source and an OTDR light source and is used for monitoring the vibration and the loss of the optical cable; optical fiber coupler, sensing optical cable and photoelectric detection module all are connected with the optical fiber circulator, pulse laser passes through optical fiber coupler and gets into the optical fiber circulator, get into the sensing optical cable after the output, the backward rayleigh scattered light that pulse laser produced inside the sensing optical cable enters into the photoelectric detection module through the optical fiber circulator, the photoelectric detection module converts light signal into the signal of telecommunication, the photoelectric detection module, data acquisition module and computer processing module connect gradually, data acquisition module converts the signal of telecommunication into digital signal and transmits to computer processing module, the utility model has the characteristics of simple structure, the monitoring is sensitive, the monitoring result is accurate.
Description
Technical Field
The utility model relates to a cable pit fire monitoring technology field especially relates to a novel cable pit fire early warning real-time monitoring system.
Background
The cable is important energy transmission equipment in various industrial production and civil industries such as electric power, steel, petrifaction, transportation and the like, and the safe operation of the cable is a very important problem in various industries. For years, although many safety measures and technologies are adopted, the cables in the cable duct still have many hidden dangers, and safety accidents still occur occasionally. The power equipment such as a power plant, a transformer substation cable tunnel, a cable interlayer, a cable trench, a cable shaft and the like has external force damage and fire safety hidden dangers in long-term high-voltage operation, the cable trench is complex in environment, and in case of fire, except for the damage of the equipment, the abnormal interruption of power supply can bring great loss to the social and economic development. In addition, the existing cable trench fire alarm real-time monitoring system has the problem that due to the fact that a light source in a photoelectric detection module is single, interference signals exist in the monitoring process, and false alarm is prone to occurring. Therefore, based on the above problems, it is highly desirable to provide a new and novel cable duct fire early warning real-time monitoring system.
Disclosure of Invention
The utility model aims at providing a novel cable pit conflagration early warning real-time monitoring system adopts FVS light source and OTDR light source to monitor the vibration and the loss signal of cable respectively to the realization has simple structure, monitors sensitive, the accurate characteristics of monitoring result to the monitoring function of cable.
In order to achieve the above object, the utility model provides a following scheme:
the utility model provides a novel cable pit fire early warning real-time monitoring system, includes: the device comprises a light source module, an optical fiber coupler, an optical fiber circulator, a sensing optical cable, a photoelectric detection module, a data acquisition module and a computer processing module; the light source module comprises an FVS light source and an OTDR light source, the FVS light source is used for monitoring a vibration signal of the sensing optical cable, and the OTDR light source is used for monitoring microbending loss of any point of the sensing optical cable; the output end of the optical fiber coupler, the input end of the sensing optical cable and the input end of the photoelectric detection module are connected with the optical fiber circulator, the pulse laser emitted by the light source module enters the optical fiber circulator after being coupled by the optical fiber coupler, and enters the external sensing optical cable after being output by the optical fiber circulator, backward Rayleigh scattered light generated by the pulse laser in the sensing optical cable is output through the optical fiber circulator and enters the photoelectric detection module, the photoelectric detection module converts the optical signal of the backward Rayleigh scattering light into an electric signal, the photoelectric detection module is connected with the data acquisition module, the data acquisition module is connected with the computer processing module and is used for converting the electric signals into digital signals and transmitting the digital signals to the computer processing module.
Optionally, the pulsed laser emitted by the light source module is input from the 1 end and output from the 2 end of the optical fiber circulator; the backward Rayleigh scattering light is input from the end 2 and output from the end 3 of the optical fiber circulator.
Optionally, the FVS light source uses a DFB semiconductor laser or a DFB fiber laser with continuous output power greater than 10MW and line width less than 100kHz, and the OTDR light source uses an FP semiconductor laser with continuous output power greater than 4MW and bandwidth of 2-10 nm.
Optionally, the optical fiber coupler is a 1 × 2 optical fiber coupler.
Optionally, the system further includes a display module, the display module is connected to the computer processing module, and the display module is configured to display the monitoring result.
Optionally, the sampling bandwidth of the data acquisition module is 31.25-250 MHz.
Optionally, the photodetection module is provided with an FVS signal stage and an OTDR signal stage, where the FVS signal stage includes a 2-level electrical signal amplifier, the dynamic range is 18-20dB, the OTDR signal stage includes a 3-level electrical signal amplifier, and the dynamic range is 22-25 dB.
According to the utility model provides a concrete embodiment, the utility model discloses a following technological effect: the utility model provides a novel cable pit fire early warning real-time monitoring system adopts light source module, fiber coupler, optic fibre circulator, photoelectric detection module, data acquisition module, computer processing module and display module, through gathering the backward rayleigh scattered light signal that pulse laser produced in sensing optical cable to handle and analyze the light signal, thereby realize the monitoring to cable state in the cable pit, simple structure; the FVS light source and the OTDR light source are adopted to monitor the vibration signal along the cable and the microbending loss signal at any point of the cable respectively, so that the daily interference signal and the actual detection information can be distinguished, the accuracy of system alarm is improved, and the false alarm is reduced. The utility model provides a novel cable pit conflagration early warning real-time monitoring system has simple structure, monitors sensitive, the accurate characteristics of monitoring result.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural view of the novel cable trench fire early warning real-time monitoring system of the utility model;
fig. 2 is an OTDR technical phase detection schematic diagram of the cable trench fire early warning real-time monitoring system of the utility model;
description of reference numerals: 1. an FVS light source; 2. an OTDR light source; 3. a fiber coupler; 4. a fiber optic circulator; 5. a sensing optical cable; 6. a photoelectric detection module; 7. a data acquisition module; 8. a computer processing module; 9. and a display module.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The utility model aims at providing a novel cable pit conflagration early warning real-time monitoring system adopts FVS light source and OTDR light source to monitor the vibration and the loss signal of cable respectively to the realization has simple structure, monitors sensitive, the accurate characteristics of monitoring result to the monitoring function of cable.
In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.
The utility model provides a novel cable pit fire early warning real-time monitoring system, as shown in FIG. 1, include: the optical fiber ring device comprises a light source module, an optical fiber coupler 3, an optical fiber circulator 4, a sensing optical cable 5, a photoelectric detection module 6, a data acquisition module 7, a computer processing module 8 and a display module 9, wherein the optical fiber coupler 3 adopts a 1 x 2 optical fiber coupler, the output end of the optical fiber coupler 3, the input end of the sensing optical cable 5 and the input end of the photoelectric detection module 6 are all connected with the optical fiber circulator 4, the data acquisition module 7 is electrically connected with the photoelectric detection module 6, the computer processing module 8 is electrically connected with the data acquisition module 7, and the display module 9 is electrically connected with the computer processing module 8;
the pulse laser emitted by the light source module enters the end 1 of the optical fiber circulator 4 after being coupled by the optical fiber coupler 3, the pulse laser enters the external sensing optical cable 5 after being output from the end 2 of the optical fiber circulator 4, backward rayleigh scattered light generated by the pulse laser in the sensing optical cable 5 returns to the end 2 of the optical fiber circulator 4 and is output from the end 3 of the optical fiber circulator 4 to enter the photoelectric detection module 6, the photoelectric detection module 6 converts an optical signal of the backward rayleigh scattered light into an electrical signal, the data acquisition module 7 converts the electrical signal into a digital signal and transmits the digital signal to the computer processing module 8, the computer processing module 8 analyzes the digital signal, and analyzes and obtains a vibration signal along the sensing optical cable 5 or micro-bending loss of any point through a related demodulation algorithm and transmits a monitoring result to the display module 9, the display module 9 displays the monitoring result;
the light source module comprises an FVS light source 1 and an OTDR light source 2, the FVS light source 1 is used for monitoring a vibration signal of the sensing optical cable 5, and the OTDR light source 2 is used for monitoring microbending loss of any point of the sensing optical cable 5; the light source module can start any one of the FVS light source 1 and the OTDR light source 2 to output pulse laser, the photoelectric detection module 6 has 2 detection gears, which are an FVS signal gear and an OTDR signal gear, and the photoelectric detection module 6 enables the detection gear corresponding to the corresponding light source, thereby realizing the detection function of the FVS system or the OTDR system;
in the above optical path structure, if the OTDR light source 2 and the corresponding detection and demodulation module and algorithm are not added, and only the FVS light source 1 is used, a conventional distributed optical fiber vibration sensing system (FVS system) is formed, and its working principle is as follows:
when the pulse laser is transmitted in the optical fiber, Rayleigh scattering can be generated due to microscopic unevenness of the refractive index of the optical fiber, and vibration sensing monitoring of the optical fiber can be realized when the phase of the Rayleigh scattering is demodulated; the OTDR technique demodulates the phase of an optical signal in an optical fiber, and the optical phase of a corresponding point changes when the optical fiber senses vibration, as shown in fig. 2;
assuming that there are M randomly distributed independent rayleigh scattering cells within Δ L and that the polarization of these scatterings is the same, the sum of the M scattered field vectors is expressed as:
in the formula rkAnd are and
vector sums of amplitude and phase, a, of M back-scatterings of the kth fiber in a pulseiAnd ΩiRespectively the amplitude and phase, r, of the ith backscatter in a length of Δ L fiberk、
aiAnd ΩiAre all assumed to be random variables, assume aiAnd ΩiAre all independent and the distribution is the same for all i, and ΩiIs uniformly distributed over the (-pi, pi) interval, when the pulse width is N Δ L, the interference field from the backscattered light at distance M Δ L can be expressed as:
wherein, Pk、rkAnd
respectively representing the polarization, reflectivity and phase of the kth mirror, thetakThe phase change of the invasion vibration introduced into the kth reflector is shown, the phase changes of different vibration points of the system cannot be influenced mutually, and the sub-second-order scanning speed and accurate positioning can be realized for the whole optical cable line of dozens of kilometers;
when fire hazard occurs in the cable duct, the heating of the optical cable body can cause thermal expansion of materials, meanwhile, local heating is usually caused by cable insulation deterioration and arc breakdown and can be accompanied with discharge, and then the optical cable starts local combustion, and finally, a fire hazard is formed; each step of the thermal expansion, the optical cable surface breakdown discharge and the local combustion has a characteristic vibration signal, and the vibration sensed by the communication optical cable in the cable trench can be detected and positioned by the distributed optical fiber sensing technology, so that an early warning effect is achieved; however, if the optical cable is subjected to environmental interference such as water flow impact, mouse gnawing and the like, a vibration signal can be detected, and the optical cable becomes a main false alarm source, and at the moment, if the loss of the optical cable can be monitored through the OTDR technology, the optical cable microbending loss caused by the environmental interference can be identified, so that false alarms can be effectively filtered, and the effect of the distributed optical fiber sensing technology on cable trench fire early warning is improved;
distributed optical fiber loss and vibration sensing positioning is based on an OTDR (optical time domain reflectometry) technology, a vibration position is obtained by measuring time delay between injected pulse laser and a received signal, the time required for backward scattering light generated by incident light to return to an optical fiber incident end is T, the distance traveled by the pulse laser in an optical fiber is 2l, 2l is vt, v is the propagation speed of light in the optical fiber, the distance l between a signal point and a light source can be obtained by measuring the time T, the positioning precision P of a distributed optical fiber sensing system is related to the optical pulse width Delta T of an optical fiber of an injector, and the relationship is as follows:
wherein c is the speed of light in vacuum, and n is the refractive index of the fiber core of the sensing fiber 5;
the spatial resolution of the sensing system is the minimum spatial dimension of the vibration signals which can be distinguished by the system, and during macroscopic measurement, the spatial resolution can be expressed as the minimum distance between two different vibration signals which can be distinguished by the system, for an optical part, the improvement of the spatial resolution is mainly related to the time width of a pulse light source, the smaller the width is, the higher the resolution (the smaller the value is), therefore, as long as an OTDR light source 2 is added into the system, and meanwhile, the scattered light intensity at different positions is detected and calculated, whether microbending loss occurs at any point of the optical cable can be detected in real time;
the utility model discloses a FVS light source 1 among the light source module, in order to reach the required sensing action of distributed optical fiber vibration sensing system, require its bandwidth (or frequency linewidth) very narrow, the frequency linewidth is less than 100kHz at least, when the actual lectotype, optional continuous output power is greater than 10MW, the linewidth is less than 100 kHz's DFB semiconductor laser or DFB fiber laser, OTDR light source 2 among the light source module can adopt FP semiconductor laser, continuous output power is greater than 4MW, the bandwidth is about 2-10 nm; in practical use, the intensity of a pulse emitted by the FVS light source 1 in the operation of the optical fiber is weaker than that of a pulse emitted by the OTDR light source 2, and scattered light of the FVS system returning to the photoelectric detection module 6 is weaker than scattered light of the OTDR system returning to the photoelectric detection module 6 by several orders of magnitude; meanwhile, the vibration signal of the FVS system also needs a larger detection bandwidth, generally requires more than 100MHz, the larger the detection bandwidth, the better the OTDR system scattering light generally needs only a detection bandwidth of 10-50MHz, therefore, the utility model discloses a photoelectric detection module 6 and data acquisition module 7, the sampling bandwidth of data acquisition module 7 is adjustable for 31.25-250MHz, the FVS signal is collected with 250MHz, the OTDR signal is collected with 31.25MHz, photoelectric detection module 6 has 2 detection gears, the FVS signal gear includes 2-level electric signal amplifier, dynamic range 18-20dB, the OTDR signal gear includes 3-level electric signal amplifier, dynamic range 22-25 dB;
the utility model discloses a be used for cable pit fire alarm real-time monitoring system, in original distributed optical fiber vibration sensing system, light source module removes original narrow linewidth FVS light source, and the light source is used to new integrated Optical Time Domain Reflectometer (OTDR), improves former FVS system simultaneously photoelectric detection module 6 makes it accessible different gear adjustment on detection bandwidth and detection signal dynamic range, comes the scattered light of compatible detection FVS and OTDR's scattered light; other optical path modules, circuit modules, a computer processing module 8 and a display module 9 in the system can be shared, so that the original FVS system has the function of high-sensitivity OTDR, can detect the microbending condition of the optical cable and then combine with vibration sensing information of the detection optical cable for analysis, distinguish daily interference signals and detection signals required by actual cable trench fire early warning, improve the accuracy of system alarm and reduce false alarm.
The utility model provides a novel cable pit fire early warning real-time monitoring system adopts light source module, fiber coupler, optic fibre circulator, photoelectric detection module, data acquisition module, computer processing module and display module, through gathering the backward rayleigh scattered light signal that pulse laser produced in sensing optical cable to handle and analyze the light signal, thereby realize the monitoring to cable state in the cable pit, simple structure; the FVS light source and the OTDR light source are adopted to monitor the vibration signal along the cable and the microbending loss signal at any point of the cable respectively, so that the daily interference signal and the actual detection information can be distinguished, the accuracy of system alarm is improved, and the false alarm is reduced. The utility model provides a novel cable pit conflagration early warning real-time monitoring system has simple structure, monitors sensitive, the accurate characteristics of monitoring result.
The principle and the implementation of the present invention are explained herein by using specific examples, and the above description of the embodiments is only used to help understand the method and the core idea of the present invention; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the concrete implementation and the application scope. In summary, the content of the present specification should not be construed as a limitation of the present invention.
Claims (7)
1. The utility model provides a novel cable pit fire early warning real-time monitoring system which characterized in that includes: the device comprises a light source module, an optical fiber coupler, an optical fiber circulator, a sensing optical cable, a photoelectric detection module, a data acquisition module and a computer processing module; the light source module comprises an FVS light source and an OTDR light source, the FVS light source is used for monitoring a vibration signal of the sensing optical cable, and the OTDR light source is used for monitoring microbending loss of any point of the sensing optical cable; the output end of the optical fiber coupler, the input end of the sensing optical cable and the input end of the photoelectric detection module are connected with the optical fiber circulator, the pulse laser emitted by the light source module enters the optical fiber circulator after being coupled by the optical fiber coupler, and enters the external sensing optical cable after being output by the optical fiber circulator, backward Rayleigh scattered light generated by the pulse laser in the sensing optical cable is output through the optical fiber circulator and enters the photoelectric detection module, the photoelectric detection module converts the optical signal of the backward Rayleigh scattering light into an electric signal, the photoelectric detection module is connected with the data acquisition module, the data acquisition module is connected with the computer processing module and is used for converting the electric signals into digital signals and transmitting the digital signals to the computer processing module.
2. The novel cable trench fire early warning real-time monitoring system as claimed in claim 1, wherein pulse laser emitted by the light source module is input from end 1 and output from end 2 of the optical fiber circulator; the backward Rayleigh scattering light is input from the end 2 and output from the end 3 of the optical fiber circulator.
3. The novel cable trench fire early warning real-time monitoring system as claimed in claim 1, wherein the FVS light source employs a DFB semiconductor laser or a DFB fiber laser having a continuous output power of more than 10MW and a line width of less than 100kHz, and the OTDR light source employs an FP semiconductor laser having a continuous output power of more than 4MW and a bandwidth of 2-10 nm.
4. The novel cable trench fire early warning real-time monitoring system as claimed in claim 1, wherein the optical fiber coupler is a 1-by-2 optical fiber coupler.
5. The novel cable trench fire early warning real-time monitoring system of claim 1, further comprising a display module, wherein the display module is connected with the computer processing module, and the display module is used for displaying monitoring results.
6. The novel cable trench fire early warning real-time monitoring system as claimed in claim 1, wherein the sampling bandwidth of the data acquisition module is 31.25-250 MHz.
7. The novel cable trench fire early warning real-time monitoring system of claim 1, wherein the photoelectric detection module is provided with an FVS signal stage and an OTDR signal stage, the FVS signal stage comprises a 2-stage electrical signal amplifier, the dynamic range is 18-20dB, the OTDR signal stage comprises a 3-stage electrical signal amplifier, and the dynamic range is 22-25 dB.
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