Anti-electromagnetic interference natural gas pipeline optical fiber sensor vibration monitoring system

Abstract

The utility model discloses an anti-electromagnetic interference natural gas pipeline optical fiber sensor vibration monitoring system comprising a sensing optical cable and a narrow-band laser, and the sensing optical cable is accompanied with a natural gas buried pipeline; the output end of the narrow-band laser is connected with the input end of the modulator, the output end of the modulator is connected with the input end of the optical signal amplification module, the output end of the optical signal amplification module is connected with the optical fiber coupler, and the optical fiber coupler is further connected with the photoelectric detector and the sensing optical cable. The output end of the photoelectric detector is connected with the input end of the data acquisition module, and the output end of the data acquisition module is connected with the monitoring center. By detecting the intensity change of Rayleigh scattering light signals at different moments and different positions, the position of vibration signals acting on the sensing optical cable can be detected; therefore, the vibration state change around the natural gas buried pipeline can be accurately monitored, and the real-time online monitoring of the safety state of the oil and gas pipeline is realized.

Description

Technical Field

[0001] This utility model relates to the field of natural gas pipeline vibration monitoring technology, and in particular to a natural gas pipeline fiber optic sensor vibration monitoring system that is resistant to electromagnetic interference. Background Technology

[0002] Natural gas long-distance pipelines are often buried underground in complex terrain environments. After long-term service, they may fail due to corrosion, terrain subsidence, pipe material and construction quality, mechanical construction and human damage. In particular, in recent years, pipeline safety accidents caused by malicious drilling to steal natural gas and illegal construction have frequently occurred.

[0003] Natural gas long-distance pipelines often run through densely populated areas. The lack of perimeter fencing around these pipelines leads to numerous safety issues, including third-party construction, vandalism, and heavy vehicle traffic. Despite significant investment of manpower and resources by pipeline companies, the safety situation for natural gas pipelines remains severe. Current methods of patrolling by personnel and drones are insufficient to address the "gap period" in pipeline inspections, failing to provide effective real-time detection, alerts, and responses.

[0004] Traditional monitoring methods (such as infrasound, negative pressure wave, pressure gradient, and software simulation) are all methods for monitoring pipeline failures after they occur, and cannot provide early warning of hazardous events. Therefore, it is urgent to adopt high-tech means to monitor changes in the micro-vibration state around the pipeline in a timely and accurate manner, which is of great importance for timely monitoring of the safety status of oil and gas pipelines. Utility Model Content

[0005] The purpose of this invention is to improve and innovate upon the shortcomings and problems existing in the background technology, and to provide a natural gas pipeline fiber optic sensor vibration monitoring system that is resistant to electromagnetic interference.

[0006] An electromagnetic interference-resistant fiber optic sensor vibration monitoring system for natural gas pipelines, comprising:

[0007] The sensing optical cable runs alongside the buried natural gas pipeline;

[0008] A narrowband laser, wherein the narrowband laser is used to provide a stable single-frequency light source;

[0009] A modulator, wherein the modulator is used to modulate the optical signal output by a narrowband laser;

[0010] An optical signal amplification module, wherein the optical signal amplification module is used to amplify optical signals;

[0011] An optical fiber coupler is used to couple an optical signal to a sensing optical cable for forward transmission or to decouple Rayleigh scattered light transmitted backward at different positions of the sensing optical cable.

[0012] A photodetector is used to convert Rayleigh scattered light intensity signals into analog electrical signals;

[0013] The data acquisition module is used to convert analog electrical signals into digital electrical signals;

[0014] The monitoring center includes a comparison module and an early warning module. The comparison module is used to compare the digital electrical signals corresponding to Rayleigh scattering light transmitted backward at the same location of the sensing optical cable at different times. The early warning module is used to determine whether the difference between the digital electrical signals at different times exceeds a preset threshold. When the preset threshold is exceeded, the early warning module issues an early warning.

[0015] The narrowband laser's output is connected to the modulator's input, the modulator's output is connected to the optical signal amplification module's input, the optical signal amplification module's output is connected to the fiber optic coupler, the fiber optic coupler is also connected to the photodetector and the sensing optical cable, the photodetector's output is connected to the data acquisition module's input, and the data acquisition module's output is connected to the monitoring center.

[0016] A further option is that the optical signal amplification module is an erbium-doped fiber amplifier.

[0017] A further option is that the data acquisition module is a high-speed embedded data acquisition card.

[0018] A further embodiment is that the sensing optical cable is threaded through a sleeve, which consists of an upper shell and a lower shell arranged symmetrically. The upper shell has an upper protrusion at one end near the lower shell, and the lower shell has a lower protrusion at one end near the upper shell. The upper protrusion and the lower protrusion are fixedly connected together by bolts.

[0019] A further embodiment is that the upper protrusion is provided with an upper positioning block, the lower protrusion is provided with a lower positioning block, the upper positioning block is provided with a positioning post, and the lower positioning block is provided with a positioning hole corresponding to the positioning post.

[0020] A further embodiment is that the sleeve is provided with limit blocks at intervals. The limit blocks are made of plastic material and have limit slots. The sensing optical cable passes through the limit slots. The notch size of the limit slots is smaller than the diameter of the sensing optical cable. The limit blocks are connected to the inner wall of the upper or lower housing by springs.

[0021] Compared with the prior art, the beneficial effects of this utility model are: (1) This utility model discloses a vibration monitoring system for a natural gas pipeline fiber optic sensor that resists electromagnetic interference. When the amplified light signal is transmitted in the optical fiber of the sensing cable, the photons and the fiber core lattice have particle interaction characteristics, and Rayleigh scattering light will be continuously transmitted backward. When there is external vibration acting on the sensing cable, the optical fiber at the corresponding position vibrates. Due to the photoelastic effect, the refractive index and length of the optical fiber change slightly, which causes the intensity of the Rayleigh scattering light transmitted backward at the corresponding position to change. By detecting the intensity change of the Rayleigh scattering light signal at different times and positions, the position of the vibration signal acting on the sensing cable can be detected, so as to accurately monitor the vibration state change around the buried natural gas pipeline, thereby realizing real-time online monitoring of the safety status of the oil and gas pipeline. Moreover, the optical fiber itself is composed of quartz material and is completely electrically insulated. At the same time, the signal of the optical fiber sensor is carried by the optical fiber, which is intrinsically safe and not affected by any external electromagnetic environment. In addition, the outstanding advantage of the optical fiber is that it transmits a large amount of data and has low loss. Without the need for a relay, it can realize remote monitoring over tens of kilometers.

[0022] (2) By placing the sensing optical cable in the sleeve, the present invention amplifies the external vibration signal by arranging the sensing optical cable inside the sleeve and utilizing the cavity structure formed by the sleeve itself; in addition, the sleeve can also provide effective protection for the internal sensing optical cable.

[0023] (3) This utility model uses the cooperation of spring, limit block and limit slot to restrict the sensing optical cable on the one hand, so that the spring can further amplify the vibration signal received by the sensing optical cable; on the other hand, the design of the limit slot makes the installation process of the sensing optical cable simple and quick. The staff only needs to insert the optical cable into the limit slot to complete the fixation, which greatly saves installation time and labor costs. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a fiber optic sensor vibration monitoring system for natural gas pipelines that is resistant to electromagnetic interference, provided in an embodiment of this utility model.

[0026] Figure 2 This is a schematic diagram of the structure of the monitoring center provided in this embodiment of the utility model;

[0027] Figure 3 This is a cross-sectional structural diagram of the sleeve provided in this embodiment of the utility model;

[0028] Figure 4 This is a schematic diagram of the casing and the accompanying structure of the buried natural gas pipeline provided in this embodiment of the utility model.

[0029] Reference numerals: 1. Narrowband laser; 2. Modulator; 3. Optical signal amplification module; 4. Fiber optic coupler; 5. Sensing optical cable; 6. Photodetector; 7. Data acquisition module; 8. Monitoring center; 801. Comparison module; 802. Early warning module; 9. Sleeve; 901. Upper housing; 9011. Upper protrusion; 9012. Upper positioning block; 902. Lower housing; 9021. Lower protrusion; 9022. Lower positioning block; 10. Spring; 11. Limiting block; 111. Limiting bayonet; 12. Bolt; 13. Positioning post; 14. Buried natural gas pipeline. Detailed Implementation

[0030] To make the objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] Please see Figures 1-2 This utility model provides a vibration monitoring system for natural gas pipelines using fiber optic sensors to resist electromagnetic interference. The system includes a narrowband laser 1, whose output is connected to the input of a modulator 2. The output of the modulator 2 is connected to the input of an optical signal amplification module 3. The output of the optical signal amplification module 3 is connected to an optical fiber coupler 4. The optical fiber coupler 4 is also connected to a photodetector 6 and a sensing optical cable 5. The output of the photodetector 6 is connected to the input of a data acquisition module 7, and the output of the data acquisition module 7 is connected to a monitoring center 8.

[0033] The sensing optical cable 5 runs alongside the buried natural gas pipeline 14, meaning it is installed along the axial direction of the pipeline. The sensing optical cable 5 is a standard single-mode communication optical cable. When the sensing optical cable 5 vibrates due to external disturbances, such as a pipe burst, theft via drilling, or third-party excavation in the buried natural gas pipeline 14, the optical fiber in the corresponding location will vibrate. Due to the photoelastic effect, the refractive index and length of the optical fiber undergo slight changes, causing a change in the intensity of Rayleigh scattering light transmitted backward at the corresponding location. By detecting the intensity changes of the Rayleigh scattering light signal at different times and locations, the location of the vibration signal acting on the sensing optical cable 5 can be detected, thus enabling accurate monitoring of the vibration state changes around the buried natural gas pipeline 14.

[0034] The narrowband laser 1 is used to provide a stable single-frequency light source; the modulator 2 is used to modulate the optical signal output by the narrowband laser 1.

[0035] The optical signal amplification module 3 can be an erbium-doped fiber amplifier. The optical signal amplification module 3 is used to amplify the optical signal, and the optical signal amplification module 3 can be selected according to the monitoring distance requirements.

[0036] The fiber optic coupler 4 is used to couple optical signals to the sensing optical cable 5 for forward transmission or to decouple Rayleigh scattered light transmitted backward from different positions of the sensing optical cable 5; that is, the signal light amplified by the optical signal amplification module 3 is injected from one end of the sensing optical cable 5 after passing through the fiber optic coupler 4, and at the same time, the fiber optic coupler 4 can also receive Rayleigh scattered light transmitted backward from the sensing optical cable 5.

[0037] The photodetector 6 is used to convert the Rayleigh scattering light intensity signal into an analog electrical signal; the data acquisition module 7 is used to convert the analog electrical signal into a digital electrical signal, and the data acquisition module 7 can be a high-speed embedded data acquisition card.

[0038] The monitoring center 8 includes at least a comparison module 801 and an early warning module 802. The comparison module 801 is used to compare the digital electrical signals corresponding to the Rayleigh scattering light transmitted backward at different times from the same position on the sensing optical cable 5, and can obtain the differential signal of the Rayleigh scattering light transmitted backward at different times from the same position. The early warning module 802 is used to determine whether the difference between the digital electrical signals at different times exceeds a preset threshold, that is, whether the differential signal exceeds a preset threshold. When the preset threshold is exceeded, the early warning module 802 issues an early warning. The early warning module 802 can trigger an alarm to issue an audible and visual alarm, so that dispatchers can notice the abnormal information of the sensing optical cable 5 in a timely manner and take corresponding measures to deal with it.

[0039] In summary, the signal light emitted by the narrowband laser 1 is modulated and amplified, then injected from one end of the sensing optical cable 5 through the fiber optic coupler 4. During transmission through the sensing optical cable 5, nonlinear scattering occurs, and the back Rayleigh scattered light is decoupled by the fiber optic coupler 4 and converted into an analog electrical signal by the photodetector 6. After being acquired by the high-speed embedded data acquisition card, it is analyzed and processed by the comparison module 801 and the early warning module 802 of the monitoring center 8. When the sensing optical cable 5 vibrates due to external disturbances, such as when the buried natural gas pipeline 14 bursts, is burglarized by drilling, or is excavated by a third party, the optical fiber of the sensing optical cable 5 at the corresponding location will vibrate. Due to the photoelastic effect, the refractive index and length of the optical fiber will change slightly, causing the intensity of the Rayleigh scattered light transmitted backward at the corresponding location to change. The comparison module 801 of the monitoring center 8 compares and analyzes the Rayleigh scattered light transmitted backward at the same location at different times, and obtains the differential signal of the Rayleigh scattered light signal at the same location at different times. This allows the detection of the location where the vibration signal acts on the sensing optical cable 5, thereby accurately monitoring the changes in the vibration state around the buried natural gas pipeline 14.

[0040] For further details, please refer to Figures 3-4 To amplify external vibration signals, the sensing optical cable 5 is inserted into a sleeve 9. The sleeve 9 consists of an upper shell 901 and a lower shell 902 arranged symmetrically. The upper shell 901 has an upper protrusion 9011 near the lower shell 902, and the lower shell 902 has a lower protrusion 9021 near the upper shell 901. The upper protrusion 9011 and the lower protrusion 9021 are fixedly connected together by bolts 12. Since the sensing optical cable 5 is arranged inside the sleeve 9, the cavity structure formed by the sleeve 9 itself can amplify and enhance the sensitivity of external vibration signals. In addition, the sleeve 9 can also provide effective protection for the internal sensing optical cable 5.

[0041] Preferably, the upper protrusion 9011 is provided with an upper positioning block 9012, and the lower protrusion 9021 is provided with a lower positioning block 9022. The upper positioning block 9012 is provided with a positioning post 13, and the lower positioning block 9022 is provided with a positioning hole corresponding to the positioning post 13. The cooperation between the positioning post 13 and the positioning hole facilitates rapid positioning and efficient alignment between the upper housing 901 and the lower housing 902, enabling efficient alignment of the threaded grooves on the upper protrusion 9011 and the lower protrusion 9021.

[0042] Furthermore, the sleeve 9 is provided with limit blocks 11 at intervals. The limit blocks 11 are made of plastic and have limit slots 111 on them. The sensing optical cable 5 passes through the limit slots 111. The notch size of the limit slots 111 is smaller than the diameter of the sensing optical cable 5. The limit blocks 11 are connected to the inner wall of the upper housing 901 or the lower housing 902 by springs 10. The sensing optical cable 5 can be squeezed into the limit slots 111, which facilitates the quick installation of the sensing optical cable 5 in the limit slots 111, making the installation process of the sensing optical cable 5 simple and quick, and greatly saving installation time and labor costs. At the same time, since the sensing optical cable 5 passes through the limit blocks 11, and the limit blocks 11 are connected to the inner wall of the sleeve 9 by springs 10, the springs 10 can further amplify the vibration signals received by the sensing optical cable 5, making the sensing optical cable 5 more sensitive to external vibration signals.

[0043] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0045] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. Although embodiments of this utility model have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this utility model, the scope of which is defined by the claims and their equivalents.

Claims

1. A natural gas pipeline fiber optic sensor vibration monitoring system that is resistant to electromagnetic interference, characterized by, The application relates to a natural gas pipeline monitoring system, which comprises the following parts: a sensing optical cable (5) which is arranged along a natural gas buried pipeline (14); a narrow-band laser (1) which is used for providing a stable single-frequency light source; a modulator (2) which is used for modulating the light signal output by the narrow-band laser (1); an optical signal amplification module (3) which is used for amplifying the light signal; an optical fiber coupler (4) which is used for coupling the light signal into the sensing optical cable (5) for forward transmission or decoupling Rayleigh scattering light back-transmitted by the sensing optical cable (5) at different positions; a photoelectric detector (6) which is used for converting the Rayleigh scattering light intensity signal into an analog electric signal; a data acquisition module (7) which is used for converting the analog electric signal into a digital electric signal; a monitoring center (8) which comprises a comparison module (801) and an early warning module (802), the comparison module (801) is used for comparing the digital electric signals corresponding to the Rayleigh scattering light back-transmitted at different time instants by the sensing optical cable (5) at the same position; the early warning module (802) is used for judging whether the difference between the digital electric signals at different time instants exceeds a preset threshold value, and the early warning module (802) sends out a warning when the preset threshold value is exceeded. The output end of the narrow-band laser (1) is connected with the input end of the modulator (2), the output end of the modulator (2) is connected with the input end of the optical signal amplification module (3), the output end of the optical signal amplification module (3) is connected with the optical fiber coupler (4), the optical fiber coupler (4) is further connected with the photoelectric detector (6) and the sensing optical cable (5) respectively, the output end of the photoelectric detector (6) is connected with the input end of the data acquisition module (7), and the output end of the data acquisition module (7) is connected with the monitoring center (8).

2. The electromagnetic interference resistant natural gas pipeline optical fiber sensor vibration monitoring system of claim 1, wherein: The optical signal amplification module (3) is an erbium-doped fiber amplifier.

3. The electromagnetic interference resistant natural gas pipeline optical fiber sensor vibration monitoring system of claim 1, wherein: The data acquisition module (7) is a high-speed embedded data acquisition card.

4. The electromagnetic interference immune natural gas pipeline optical sensor vibration monitoring system of claim 1, wherein: The sensing optical cable (5) is arranged in a sleeve (9), the sleeve (9) is composed of symmetrically arranged upper and lower shells (901) and (902), the upper shell (901) is provided with an upper protruding part (9011) at one end close to the lower shell (902), the lower shell (902) is provided with a lower protruding part (9021) at one end close to the upper shell (901), and the upper protruding part (9011) and the lower protruding part (9021) are fixedly connected through bolts (12).

5. A natural gas pipeline optical fiber sensor vibration monitoring system against electromagnetic interference according to claim 4, characterized in that: The upper protruding part (9011) is provided with an upper positioning block (9012), the lower protruding part (9021) is provided with a lower positioning block (9022), the upper positioning block (9012) is provided with a positioning column (13), and the lower positioning block (9022) is provided with a positioning hole corresponding to the positioning column (13).

6. The electromagnetic interference immune natural gas pipeline optical fiber sensor vibration monitoring system of claim 4, wherein: The sleeve (9) is provided with a limiting block (11) at intervals, the limiting block (11) is made of plastic material, a limiting socket (111) is formed on the limiting block (11), the sensing optical cable (5) is arranged in the limiting socket (111), the size of the limiting socket (111) is smaller than the diameter of the sensing optical cable (5), and the limiting block (11) is connected with the inner wall of the upper shell (901) or the lower shell (902) through a spring (10).

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