WO2008017276A1 - A distributed optical fiber warning and sensing system for oil and gas pipeline - Google Patents
A distributed optical fiber warning and sensing system for oil and gas pipeline Download PDFInfo
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- WO2008017276A1 WO2008017276A1 PCT/CN2007/070414 CN2007070414W WO2008017276A1 WO 2008017276 A1 WO2008017276 A1 WO 2008017276A1 CN 2007070414 W CN2007070414 W CN 2007070414W WO 2008017276 A1 WO2008017276 A1 WO 2008017276A1
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- fiber grating
- fiber
- grating mirror
- optical
- pipeline
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 18
- 238000002310 reflectometry Methods 0.000 claims abstract description 33
- 230000003287 optical effect Effects 0.000 claims abstract description 29
- 238000001228 spectrum Methods 0.000 claims abstract description 14
- 230000001427 coherent effect Effects 0.000 claims abstract description 4
- 239000000835 fiber Substances 0.000 claims description 89
- 238000001514 detection method Methods 0.000 claims description 8
- 238000012544 monitoring process Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000032683 aging Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012806 monitoring device Methods 0.000 description 2
- 239000011295 pitch Substances 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 238000001069 Raman spectroscopy Methods 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 238000002168 optical frequency-domain reflectometry Methods 0.000 description 1
- 238000000253 optical time-domain reflectometry Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
- F17D5/00—Protection or supervision of installations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
- G01D5/35309—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer
- G01D5/35316—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer using a Bragg gratings
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/08—Testing mechanical properties
- G01M11/083—Testing mechanical properties by using an optical fiber in contact with the device under test [DUT]
Definitions
- the invention belongs to the technical field of optical fiber sensing and oil and gas pipeline alarming, and particularly relates to a distributed optical fiber oil and gas pipeline alarm sensing system.
- the first step in drilling oil and gas pipelines is to dig up the soil around the pipeline, and there will be vibration during the excavation process.
- the second step is to punch the oil and gas pipeline, which will cause vibration.
- the problems of the prior art are as follows: First, the distributed optical fiber sensing device optical time domain reflectometer (0TDR) and optical frequency domain reflectometer (0FDR) are not suitable for the oil and gas pipeline warning device because they are sensitive to vibration. On-line detection; Second, the MZ interferometer has a high false alarm rate, difficult positioning, and practical application of distance. Third, the negative pressure detection of the oil and gas pipeline alarm cannot provide an early warning of the incident.
- TDR optical time domain reflectometer
- FDR optical frequency domain reflectometer
- Low reflectivity fiber grating mirrors are provided in several fibers along the pipeline, the number of which is determined by the length of the pipeline.
- the sideband filter is a sideband filter with the function of selecting the sideband order.
- Figure 4 is a schematic diagram of the fiber grating mirror without external disturbance.
- a high reflectance fiber grating mirror 4 and a series of low reflectance fiber grating mirrors 5 are disposed in the fiber laid along the pipeline, and the pitches thereof are: high reflectance fiber grating mirror 4 and optical circulator 3 spacing are L0, the distance between the high reflectance fiber grating mirror 4 and the first low reflectance fiber grating mirror is L1, and the distance between the first low reflectance fiber grating mirror and the second low reflectance fiber grating mirror is L2, the rest and so on.
- Design and debug demodulation detection equipment which consists of high coherence length laser, optical circulator, photoelectric detector, amplifier, sideband filter, fast Fourier transformer, spectrum analyzer, computer.
- the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, equivalent change, and modification to the above embodiments in accordance with the technical spirit of the present invention belong to the present technology. Within the scope of the program.
Abstract
A distributed optical fiber warning and sensing system for oil and gas pipeline, the coherent light emitted from a highly coherent length adjustable laser (1) is inputted to the input end (a) of an optical circulator (3) via a sensing optical fiber (2), and outputted to a high reflectivity optical fiber grating reflector (4) and a low reflectivity optical fiber grating reflector (5) from the first output end (b) of the optical circulator (3), and returned to the optical circulator (3), and then outputted to a photodiode (6) from the second output end (c) of the optical circulator (3); the needed information is analyzed by means of a Fast Fourier Transformer (8), a side band filter (9) and a spectrum analyzer (10) after the signals from the photodiode (6) are amplified by an amplifier (7), and finally displayed and warned by means of a computer control system (11) and an early warning (12).
Description
分布式光纤油气管线警戒传感系统 技术领域 Distributed optical fiber oil and gas pipeline warning sensing system
本发明属于光纤传感、油气管线报警技术领域，尤其涉及分布式光纤油气管线警戒传 感系统。 The invention belongs to the technical field of optical fiber sensing and oil and gas pipeline alarming, and particularly relates to a distributed optical fiber oil and gas pipeline alarm sensing system.
背景技术 Background technique
光纤和光纤光栅传感器是近几年高速发展的新型传感器， 光纤和光纤光栅传感器可 集信息的传感与传输于一体，与传统的传感器相比它具有很多优势：如防爆，抗电磁干扰， 抗腐蚀，抗震动，耐高温，体积小， 重量轻，灵活方便， 特别能在恶劣环境下使用。 Fiber optic and fiber Bragg grating sensors are new types of sensors that have been developed at a high speed in recent years. Fiber optic and fiber Bragg grating sensors can integrate information sensing and transmission. Compared with traditional sensors, they have many advantages: such as explosion-proof, anti-electromagnetic interference, and anti-electromagnetic interference. Corrosion, anti-vibration, high temperature resistance, small size, light weight, flexible and convenient, especially for use in harsh environments.
分布式光纤传感器除了以上上述的优点外， 它能够测量传感光纤所在的任何一点的 信号， 目前市场广泛应用的有光时域反射仪 (0TDR)、 光频域反射仪 (0FDR)和各种干涉仪， 例如 M-Z干涉仪等。 分布式光纤传感器属于强度检测， 它们共同存在的问题是易受光源 起伏、 光纤弯曲、 器件老化等影响它们的测量精度和可靠性。 In addition to the above advantages, distributed fiber optic sensors can measure the signal at any point where the sensing fiber is located. Currently, the optical time domain reflectometer (0TDR), optical frequency domain reflectometer (0FDR) and various types are widely used in the market. Interferometers, such as MZ interferometers. Distributed fiber optic sensors are strength detection. They have the common problem of being susceptible to fluctuations in light source, fiber bending, and aging of devices.
光纤光栅传感器克服上述易受光源起伏、 光纤弯曲、 器件老化等影响问题， 它属于 波长编码， 不受光源起伏、 光纤弯曲、 器件老化等影响， 由此有很高的可靠性、 稳定性 和重复性。 由于光纤光栅传感装置是准分布式的， 它的不足是它只能测量光纤光栅传感 器所在的地方。 一般的光纤光栅传感检测系统是波长编码， 如日本专利 11-061524 每一 个光纤光栅具有不同的中心波长， 由此可以测量的数量是有限的。 也有用同一波长的如 武汉理工大学发表的一篇文章， 由于每一个光纤光栅传感器要求有较高的反射率， 被检 测的数量也是有限的。 The FBG sensor overcomes the above-mentioned problems that are susceptible to fluctuations in the light source, bending of the fiber, aging of the device, etc. It is wavelength-coded and is not affected by undulation of the light source, bending of the fiber, aging of the device, etc., thereby having high reliability, stability and repetition. Sex. Since the fiber Bragg grating sensing device is quasi-distributed, its disadvantage is that it can only measure where the fiber Bragg grating sensor is located. A general fiber Bragg grating sensing system is wavelength-coded. For example, in Japanese Patent 11-061524, each fiber grating has a different center wavelength, and thus the number that can be measured is limited. An article published by Wuhan University of Technology at the same wavelength is also used. Since each FBG sensor requires a high reflectance, the number of samples to be detected is also limited.
分布式光纤传感检测系统光时域反射仪 (0TDR)、 光频域反射仪 (0FDR)的信号来自光 纤中对温度和压力敏感的拉曼 （Raman) 和布里渊 （Bri llouin) 散射， 信号小， 为了提 高信噪比， 需要经过多次测量取平均， 并且这两种散射对震动敏感性低。 M— Z干涉检测 系统敏感性高， 但稳定性差， 对被检测物体定位困难。 Distributed Optical Fiber Sensing Detection System Optical Time Domain Reflectometry (0TDR), Optical Frequency Domain Reflectometry (0FDR) signals from temperature and pressure sensitive Raman and Brilluin scattering in the fiber, signal Small, in order to improve the signal-to-noise ratio, it is necessary to take multiple measurements and average, and these two kinds of scattering have low sensitivity to vibration. The M-Z interference detection system has high sensitivity, but the stability is poor, and it is difficult to locate the detected object.
中石油管道公司描述了对检测输油气管线的一种负压设备； 输油气管线的泄漏和盗 油， 会使得泄漏地段输油气管线两端的压力产生变化， 可以发现泄漏和泄漏的地点。 这 种装置可以发现油气已经大量泄漏时的情况， 而不能够预报即将发生盗油的事件。 PetroChina Pipeline Co., Ltd. described a negative pressure device for detecting oil and gas pipelines; leakage and stolen oil from oil and gas pipelines will cause changes in pressure at both ends of the oil and gas pipelines in the leaking area, and locations where leaks and leaks can be found. This device can detect the situation when the oil and gas has been leaked a lot, and cannot predict the event of the stolen oil.
输油气管道打孔盗油第一步需要把管道周围的泥土挖开， 挖土过程就会有震动， 第 二步是对输油气管道打孔， 这又会产生震动。 The first step in drilling oil and gas pipelines is to dig up the soil around the pipeline, and there will be vibration during the excavation process. The second step is to punch the oil and gas pipeline, which will cause vibration.
到目前为止， 国内外市场上尚无一种切实可行的输油气管线警戒传感装置
总之， 习知技术存在的问题有： 一是分布式光纤传感装置光时域反射仪 (0TDR)、 光 频域反射仪 (0FDR)由于对震动敏感低不适合输油气管线警戒传感装置中在线检测； 二是 M-Z干涉仪误报率高， 定位困难， 实际应用有距离， 三是输油气管线报警的负压检测不能 对所发事件进行预警。 So far, there is no practical oil and gas pipeline warning sensor device in the domestic and foreign markets. In short, the problems of the prior art are as follows: First, the distributed optical fiber sensing device optical time domain reflectometer (0TDR) and optical frequency domain reflectometer (0FDR) are not suitable for the oil and gas pipeline warning device because they are sensitive to vibration. On-line detection; Second, the MZ interferometer has a high false alarm rate, difficult positioning, and practical application of distance. Third, the negative pressure detection of the oil and gas pipeline alarm cannot provide an early warning of the incident.
发明内容 Summary of the invention
为克服现有技术的不足， 针对油气管线的警戒要求， 提供一种分布式光纤油气管线 警戒传感系统， 该系统结构简单、 定位准确、 监测距离长、 集感知和信号传输于一体， 可与通信光缆同步铺设等， 几乎不需维护。 还有大的监测范围， 高的灵敏度和可以预先 设置分辨率等邮电。 本发明采用的技术方案是： 一种分布式光纤输油气管线警戒传感装 置， 由高相干长度可调激光器、 传感光纤、 光环行器、 高反射率光纤光栅反射镜、 低反 射率光纤光栅反射镜、 光电二极管、 放大器、 快速傅立叶变换器、 边带滤波器、 频谱分 析仪、 计算机控制系统和预报警组成， 高相干长度可调激光器发出的相干光经过传感光 纤进入光环行器的输入端 a，由进入光环行器第一输出端 b输出到高反射率光纤光栅反射 镜和低反射率光纤光栅反射镜， 然后返回光环行器， 由光环行器的第二输出端 c输出到 光电二极管， 光电二极管的信号经由放大器放大后由快速傅立叶变换器、 边带滤波器和 频谱分析仪分析出所需要的信息， 最终由计算机控制系统和预报警显示和预警。 In order to overcome the shortcomings of the prior art, a distributed optical fiber oil and gas pipeline warning sensing system is provided for the alert requirement of oil and gas pipelines. The system has simple structure, accurate positioning, long monitoring distance, integrated sensing and signal transmission, and Communication cables are laid in parallel, and almost no maintenance is required. There is also a large monitoring range, high sensitivity and pre-set resolution and other postal and telecommunications. The technical solution adopted by the invention is: a distributed optical fiber pipeline alarm device, comprising a high coherence length tunable laser, a sensing fiber, an optical circulator, a high reflectivity fiber grating mirror, and a low reflectivity fiber grating. Mirror, photodiode, amplifier, fast Fourier transformer, sideband filter, spectrum analyzer, computer control system and pre-alarm. The coherent light from the high coherence-length tunable laser enters the input of the optical circulator through the sensing fiber. The terminal a is outputted from the first output end b of the incoming optical circulator to the high reflectivity fiber grating mirror and the low reflectivity fiber grating mirror, and then returned to the optical circulator, and outputted to the photoelectric output by the second output end c of the optical circulator The diode, the photodiode signal is amplified by the amplifier and analyzed by the fast Fourier transformer, sideband filter and spectrum analyzer, and finally the computer control system and pre-alarm display and warning.
其中， 高反射率光纤光栅反射镜的反射率至少是低反射率光纤光栅反射镜反射率 20 倍以上， 低反射率光纤光栅反射镜的反射率是 0. 5%。 The 5% of the reflectivity of the low-reflectivity fiber-optic grating mirror is at least 0.5 times.
低反射率光纤光栅反射镜在随管线铺设的光纤中设置有若干个， 其数目根据管线的 长短确定。 Low reflectivity fiber grating mirrors are provided in several fibers along the pipeline, the number of which is determined by the length of the pipeline.
高相干光激光器的相干长度必须大于被测距离的 2 11 倍， 它的中心波长与光纤光栅 反射镜和低反射率光纤光栅反射镜的中心波长相等。 The coherence length of a high-coherence dry-light laser must be greater than 2 11 times the measured distance, and its center wavelength is equal to the center wavelength of the fiber grating mirror and the low-reflectivity fiber grating mirror.
边带滤波器是具有选择边带阶数功能的边带滤波器。 The sideband filter is a sideband filter with the function of selecting the sideband order.
频谱分析仪为具有选择预定频率功能的频谱分析仪。 The spectrum analyzer is a spectrum analyzer with the function of selecting a predetermined frequency.
本发明可带来以下技术效果： The invention can bring the following technical effects:
由于采用了高反射率光纤光栅反射镜、 低反射率光纤光栅反射镜式结构， 低反射率 光纤光栅反射镜既是传感器又是反射镜， 因而本发明灵敏度高， 定位准确； Because of the high reflectivity fiber grating mirror and the low reflectivity fiber grating mirror structure, the low reflectivity fiber grating mirror is both a sensor and a mirror, so the invention has high sensitivity and accurate positioning;
由于通过本发明的高反射率光纤光栅反射镜、 低反射率光纤光栅反射镜和信号接收 分析部分可预设分辨率， 因而本发明可具有较长的监测距离和大的监测范围； Since the resolution can be preset by the high reflectance fiber grating mirror, the low reflectance fiber grating mirror and the signal receiving analysis portion of the present invention, the present invention can have a longer monitoring distance and a large monitoring range;
本发明的低反射率光纤光栅反射镜与通信光缆同步铺设、埋入地下，因而本发明几乎
不需维护， 安全性、 隐蔽性好， 很难被发觉破坏； The low reflectivity fiber grating mirror of the present invention is laid and buried underground in synchronization with the communication optical cable, and thus the present invention is almost No maintenance, security, concealment, it is difficult to be found damaged;
此外， 本发明还具有结构简单， 成本低的特点。 In addition, the invention has the characteristics of simple structure and low cost.
附图说明 DRAWINGS
图 1管道防破坏泄漏预警检测系统整体结构图示意图。 Figure 1 Schematic diagram of the overall structure of the pipeline anti-destruction leak warning detection system.
图中， 1高相干长度可调激光器、 2传感光纤、 3光环行器、 4高反射率光纤光栅反 射镜、 5低反射率光纤光栅反射镜、 6光电二极管、 7放大器、 8快速傅立叶变换器、 9 边带滤波器、 10频谱分析仪、 11计算机控制系统、 12预报警， L0为光环行器 3、 高反射 率光纤光栅反射镜 4间距， L1为高反射率光纤光栅反射镜 4与第一个低射率光纤光栅反 射镜之间的距离， 第一个低反射率光纤光栅反射镜和第二个低反射率光纤光栅反射镜的 距离为 L2， 其余依此类推。 In the figure, 1 high coherence length tunable laser, 2 sensing fiber, 3 optical circulator, 4 high reflectance fiber grating mirror, 5 low reflectivity fiber grating mirror, 6 photodiode, 7 amplifier, 8 fast Fourier transform , 9 sideband filters, 10 spectrum analyzers, 11 computer control systems, 12 pre-alarms, L0 for optical circulators 3, high reflectivity fiber grating mirrors 4 pitch, L1 for high reflectivity fiber grating mirrors 4 with The distance between the first low-resolution fiber grating mirror, the distance between the first low-reflectivity fiber grating mirror and the second low-reflectivity fiber grating mirror is L2, and so on.
图 2是宽带宽低反射率光纤光栅反射镜示意图。 Figure 2 is a schematic diagram of a wide bandwidth low reflectivity fiber grating mirror.
图 3是一段具有光纤光栅反射镜的分布式传感光纤光谱图。 Figure 3 is a spectrum of a distributed sensing fiber with a fiber grating mirror.
图 4无外界扰动时的光纤光栅反射镜光谱示意图。 Figure 4 is a schematic diagram of the fiber grating mirror without external disturbance.
图 5是第三个光纤光栅反射镜处有扰动外界扰动时的光谱示意图： 中间为主峰， 两 侧为边带。 Figure 5 is a schematic diagram of the spectrum of the third fiber grating mirror with disturbing external disturbances: the middle is the main peak and the two sides are the sidebands.
具体实施方式 detailed description
下面结合附图和实施例具体说明本发明。 The invention will be specifically described below in conjunction with the drawings and embodiments.
本发明原理如图 1所示。 The principle of the invention is shown in Figure 1.
1 )、 光源： 频率扫描激光器， 光 （电） 场为： E=EoeXp (2 ii v t) 在测量时间内， 其频率随时间线性变化： v = v o+ a t 1), Light source: Frequency scanning laser, optical (electric) field: E=Eo eX p (2 ii vt) During the measurement time, its frequency changes linearly with time: v = v o+ at
2)、 传感光纤： 2), sensing fiber:
在随管线敷设的光纤中设置高反射率光纤光栅反射镜 4和一系列的低反射率光纤光 栅反射镜 5， 它们的间距分别为： 高反射率光纤光栅反射镜 4和光环行器 3间距为 L0， 高反射率光纤光栅反射镜 4和第一个低反射率光纤光栅反射镜的距离为 Ll， 第一个低反 射率光纤光栅反射镜和第二个低反射率光纤光栅反射镜的距离为 L2， 其余依此类推。 A high reflectance fiber grating mirror 4 and a series of low reflectance fiber grating mirrors 5 are disposed in the fiber laid along the pipeline, and the pitches thereof are: high reflectance fiber grating mirror 4 and optical circulator 3 spacing are L0, the distance between the high reflectance fiber grating mirror 4 and the first low reflectance fiber grating mirror is L1, and the distance between the first low reflectance fiber grating mirror and the second low reflectance fiber grating mirror is L2, the rest and so on.
3)、 激光外差： 3), laser heterodyne:
以高反射率光纤光栅反射镜 4与第一个低反射率光纤光栅反射镜反射的光（电) 场 E。和 为例， 它们在光敏二极管 PD上产生的光电流为： ioi=k (Eo+Ei) * (E0+Ei)
=k [ (Eo*Eo+Ei*Ei) + (E0*Ei+E0Ei*) ] The optical (electrical) field E reflected by the high reflectivity fiber grating mirror 4 and the first low reflectance fiber grating mirror. And for example, the photocurrent generated on the photodiode PD is: ioi=k (Eo+Ei) * (E 0 +Ei) =k [ (Eo*Eo+Ei*Ei) + (E 0 *Ei+E 0 Ei*) ]
(直流项） （差频项） (DC term) (difference frequency term)
此光电流的交流成分为： ioiAC=Eo氺 Ει+ΕοΕι氺 =2 | Eo I I Ei | cos(w01t) 其中， ω01=2π α Δ t=2 π α (2nLo/C) = 4 π α nLo/C 同理， 对其它低反射率光纤光栅反射镜的反射光， 它们与高反射率光纤光栅反 射镜 4反射光的差频为：
ω。3=ωοι+α [2n (Li+L2)/C] ω04=ω0ι+ α [2η (L1+L2+L3) /C] 本发明正是运用上述原理， 使系统以其技术上的领先优势， 弥补了声波监测误报率 高， 传输线路复杂以及电线传输等不利因素。 而且较光纤马赫泽德 (Μ-Ζ)干涉传感具有灵 敏度高， 定位更加准确的特点。 The AC component of this photocurrent is: ioiAC=Eo氺Ει+ΕοΕι氺=2 | Eo II Ei | cos(w 01 t) where ω 01 =2π α Δ t=2 π α (2nLo/C) = 4 π α nLo/C Similarly, the difference between the reflected light of other low reflectivity fiber grating mirrors and the reflected light of the high reflectivity fiber grating mirror 4 is: ω. 3=ωοι+α [2n (Li+L2)/C] ω 0 4=ω 0 ι+ α [2η (L1+L2+L3) /C] The present invention uses the above principle to make the system technically The leading edge has made up for the unfavorable factors such as high false alarm rate of sound wave monitoring, complicated transmission lines and wire transmission. Moreover, the optical fiber Mach Zede (Μ-Ζ) interference sensor has the characteristics of high sensitivity and more accurate positioning.
下面结合附图进一步说明本发明。 The invention will now be further described with reference to the accompanying drawings.
1.1 系统组成 1.1 System components
光纤传感器 Fiber Optic Sensor
1.2扰动及部位的鉴别： 在随管线敷设的光纤中设置高反射率光纤光栅反射镜 4和 一系列的低反射率光纤光栅反射镜 5， 它们的间距分别为： 高反射率光纤光栅反射镜 4 和光环行器 3间距为 L0， 高反射率光纤光栅反射镜 4和第一个低反射率光纤光栅反射镜 的距离为 Ll， 第一个低反射率光纤光栅反射镜和第二个低反射率光纤光栅反射镜的距离 为 L2， 其余依此类推。 1.2 Disturbance and location identification: A high-reflectance fiber grating mirror 4 and a series of low-reflectance fiber grating mirrors 5 are arranged in the fiber laid along the pipeline, and their spacings are respectively: High reflectivity fiber grating mirror 4 The distance between the optical circulator 3 and the optical circulator 3 is L0, the distance between the high reflectance fiber grating mirror 4 and the first low reflectance fiber grating mirror is L1, the first low reflectance fiber grating mirror and the second low reflectivity The distance of the fiber grating mirror is L2, and so on.
若外界有一个扰动， 系统中光纤传播的反射光会有一个频率改变， 经由监视装置， 检测出其扰动类型和位置。 其中扰动类型由频谱确定， 位置由频率表征的反射镜确定。 扰动效应： If there is a disturbance in the outside world, the reflected light propagating from the fiber in the system will have a frequency change, and the type and location of the disturbance will be detected through the monitoring device. The type of disturbance is determined by the spectrum and the position is determined by a mirror characterized by frequency. Disturbance effect:
若第 i个低反射率光纤光栅反射镜与第 i+1个低反射率光纤光栅反射镜之间有一振 动使得它们之间的长度在原来的 L的基础上有一变化， i， j为正整数， 贝 IJ: If there is a vibration between the i-th low-reflectance fiber grating mirror and the i+1th low-reflectance fiber grating mirror, the length between them is changed on the basis of the original L, i, j is a positive integer , Bei IJ:
Li，i+i=L+ALsinQt
则差频《0i不改变， 而所有的差频 j〉i都将有一个附加的相位差Li,i+i=L+ALsinQt Then the difference frequency "0i does not change, and all the difference frequencies j>i will have an additional phase difference.
Φ =2 π n A Lsin Q t/ A Φ = 2 π n A Lsin Q t/ A
以及与此相位差相应的附加频率： And an additional frequency corresponding to this phase difference:
A ω =d Φ /dt=2 π n A L Ω cos Ω t/ λ A ω =d Φ /dt=2 π n A L Ω cos Ω t/ λ
其中 Ω为扰动频率， A L为光纤所在环境振动 （扰动） 所引起的光纤伸长振动幅度。 Where Ω is the disturbance frequency and A L is the amplitude of the fiber elongation vibration caused by the ambient vibration (disturbance) of the fiber.
5 ) 、 扰动部位的鉴别： 系统中有一个频率改变监视装置，如果差频 ω (π到 ω oi都未改变，而 ω oj，当 j〉 i 时 有频率改变， 则扰动产生于区间第 i个低反射率光纤光栅反射镜与第 i+1个低反射率光纤 光栅反射镜之间。 5) Identification of the disturbance part: There is a frequency change monitoring device in the system. If the difference frequency ω (π to ω oi is not changed, and ω oj, when j> i there is a frequency change, the disturbance is generated in the interval i Between a low reflectivity fiber grating mirror and an i+1th low reflectivity fiber grating mirror.
6 ) 、 系统中， FFT为快速傅立叶变换硬件， 用作信号的实时频谱分析。 微机 PC用作 FFT 的控制， 光源的扫频控制， 放大器的增益控制， 信号的分析判断显示和报警信号的产 生。 6) In the system, the FFT is fast Fourier transform hardware, which is used for real-time spectrum analysis of signals. The microcomputer PC is used as the control of the FFT, the frequency sweep control of the light source, the gain control of the amplifier, the analysis of the signal to judge the display and the generation of the alarm signal.
7 ) 如前例， 本发明可达到目的是把打孔盗油的事件的第一步， 至多在第二步时就及时发 现， 以防止管道的破坏。 7) As in the previous example, the present invention achieves the first step of the event of stealing the oil, and at the second step, it is found in time to prevent the destruction of the pipeline.
1. 3 系统组网和报警方案 1. 3 system networking and alarm scheme
本系统可以实现报警信号传输， 现有的网络接口采用以太网接口， 底层采用 TCP/IP 协议， 报警信号数据协议可由用户决定。 The system can realize alarm signal transmission. The existing network interface adopts Ethernet interface, and the bottom layer adopts TCP/IP protocol. The alarm signal data protocol can be determined by the user.
监测系统本身具有报警显示。 The monitoring system itself has an alarm display.
本发明的具体实施由以下实施例及其附图详细给出。 The specific embodiments of the present invention are given in detail by the following examples and the accompanying drawings.
1、 按照设定的要求，把光纤光栅反射镜插入传感光纤中，并要求传感光纤的损耗 小于 0. 6dB/km。 1. The loss of the sensing fiber is less than 0.6 dB/km, and the fiber-optic grating is inserted into the sensing fiber according to the set requirements.
2、 传感光纤为 GYTA53和其他铠装光缆。 2. The sensing fiber is GYTA53 and other armored cables.
3、 把传感光缆与输油气管道同时铺设。 3. Lay the sensing cable and the oil and gas pipeline at the same time.
4、 设计并调试解调检测设备， 此设备含有高相干长度激光器， 光环行器， 光电探 测器， 放大器， 边带滤波器， 快速傅立叶变换器， 频谱分析仪， 计算机组成。 以上所述仅是本发明的较佳实施例而已， 并非对本发明作任何形式上的限制， 凡是 依据本发明的技术实质对以上实施例所作任何简单修改、 等同变化和修饰， 均属于本发 明技术方案的范围内。
4. Design and debug demodulation detection equipment, which consists of high coherence length laser, optical circulator, photoelectric detector, amplifier, sideband filter, fast Fourier transformer, spectrum analyzer, computer. The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, equivalent change, and modification to the above embodiments in accordance with the technical spirit of the present invention belong to the present technology. Within the scope of the program.
Claims
权 利 要 求 Rights request
1. 一种分布式光纤输油气管线警戒传感系统， 其特征在于， 由高相干长度 可调激光器（1)、传感光纤（2)、光环行器（3)、 高反射率光纤光栅反射镜（4)、 低反射率光纤光栅反射镜 （5)、 光电二极管（6)、 放大器（7)、 快速傅立叶变换 器 （8)、 边带滤波器 （9)、 频谱分析仪 （10)、 计算机控制系统 （11) 和预报警A distributed optical fiber pipeline warpage sensing system characterized by high-coherence length tunable laser (1), sensing fiber (2), optical circulator (3), high reflectivity fiber grating reflection Mirror (4), low reflectivity fiber grating mirror (5), photodiode (6), amplifier (7), fast Fourier transformer (8), sideband filter (9), spectrum analyzer (10), Computer control system (11) and pre-alarm
(12)组成， 高相干长度可调激光器（1)发出的相干光经过传感光缆（2)进入 光环行器 （3) 的输入端 a，由进入光环行器 （3) 第一输出端 b输出到高反射率 光纤光栅反射镜（4)和低反射率光纤光栅反射镜（5)， 然后返回光环行器（3)， 由光环行器（3) 的第二输出端 c输出到光电二极管（6)， 光电二极管 （6) 的信 号经由放大器（7)放大后由快速傅立叶变换器（8)、 边带滤波器（9)和频谱分 析仪 （10) 分析出所需要的信息， 最终由计算机控制系统 （11) 和预报警 （12) 显示和预警。 (12) Composition, the coherent light emitted by the high-coherence-length tunable laser (1) enters the input end a of the optical circulator (3) through the sensing optical cable (2), and enters the optical circulator (3), the first output end b Output to a high reflectance fiber grating mirror (4) and a low reflectivity fiber grating mirror (5), and then return to the optical circulator (3), which is output from the second output c of the optical circulator (3) to the photodiode (6), the signal of the photodiode (6) is amplified by the amplifier (7), and the required information is analyzed by the fast Fourier transformer (8), the sideband filter (9) and the spectrum analyzer (10), and finally by the computer. Control system (11) and pre-alarm (12) display and warning.
2.根据权利要求 1所述的一种分布式光纤输油气管线警戒传感系统，其特征 在于， 高反射率光纤光栅反射镜 （4) 的反射率至少是低反射率光纤光栅反射镜 2. A distributed fiber optic pipeline alert sensing system according to claim 1 wherein the high reflectivity fiber grating mirror (4) has a reflectivity of at least a low reflectivity fiber grating mirror.
(5) 反射率 20倍以上， 一低反射率光纤光栅反射镜 （5) 的反射率是 0.5%。 (5) The reflectance is 20 times or more, and the reflectance of a low reflectance fiber grating mirror (5) is 0.5%.
3.根据权利要求 1所述的一种分布式光纤输油气管线警戒传感系统，其特征 在于， 低反射率光纤光栅反射镜 （5) 在随管线铺设的光纤中设置有若干个， 其 数目根据管线的长短确定。 3 . The distributed optical fiber pipeline alarm detection system according to claim 1 , wherein the low reflectance fiber grating mirror ( 5 ) is disposed in the optical fiber laid along the pipeline, and the number thereof Determined according to the length of the pipeline.
4.根据权利要求 1所述的一种分布式光纤输油气管线警戒传感系统，其特征 在于， 高相干光激光器 （1) 的相干长度必须大于被测距离的 2 II 倍， 它的中心 波长与高光纤光栅反射镜（4)和低反射率光纤光栅反射镜（5)的中心波长相等。 The distributed optical fiber pipeline alarm sensing system according to claim 1, wherein the coherence length of the high-coherence optical laser (1) must be greater than 2 II times the measured distance, and its center wavelength It is equal to the center wavelength of the high fiber grating mirror (4) and the low reflectance fiber grating mirror (5).
5.根据权利要求 1所述的一种分布式光纤输油气管线警戒传感系统，其特征 在于， 边带滤波器 （9) 是具有选择边带阶数功能的边带滤波器。 A distributed optical fiber pipeline warpage sensing system according to claim 1, wherein the sideband filter (9) is a sideband filter having a function of selecting a sideband order.
6.根据权利要求 1所述的一种新型分布式光纤输油气管线警戒传感系统，其 特征在于， 频谱分析仪 （10) 为具有选择预定频率功能的频谱分析仪。
A novel distributed fiber optic pipeline alert sensing system according to claim 1, wherein the spectrum analyzer (10) is a spectrum analyzer having a function of selecting a predetermined frequency.
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| CN 200620026938 CN200979076Y (en) | 2006-08-04 | 2006-08-04 | Distributed optical fiber oil gas pipeline alarming and sensor device |
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| CN102434783A (en) * | 2011-10-09 | 2012-05-02 | 中国计量学院 | Device for detecting leakage of optical fiber underwater long-distance transmission pipeline based on phase generator carrier demodulation |
| CN102352963B (en) * | 2011-10-09 | 2013-08-07 | 中国计量学院 | Mixing interference distributed optical fiber-based leakage detection device for underwater long-distance pipeline |
| CN103912792A (en) * | 2014-04-18 | 2014-07-09 | 青岛厚科化学有限公司 | Telescoping underground pipeline leakage warning system on basis of fiber gratings and method implemented by telescoping underground pipeline leakage warning system |
| GB2596257A (en) * | 2015-03-06 | 2021-12-22 | Silixa Ltd | Method and apparatus for optical sensing |
| GB2596257B (en) * | 2015-03-06 | 2022-06-08 | Silixa Ltd | Method and apparatus for optical sensing |
| US11719560B2 (en) | 2015-03-06 | 2023-08-08 | Silixa Ltd. | Method and apparatus for optical sensing |
| GB2571540A (en) * | 2018-02-28 | 2019-09-04 | Craley Group Ltd | Improvements in or relating to the monitoring of fluid pipes |
| GB2571540B (en) * | 2018-02-28 | 2020-10-28 | Craley Group Ltd | Improvements in or relating to the monitoring of fluid pipes |
| US11506562B2 (en) | 2018-02-28 | 2022-11-22 | Craley Group Limited | Monitoring of fluid pipes |
| CN108468950A (en) * | 2018-05-17 | 2018-08-31 | 钦州学院 | A kind of natural gas standpipe early warning system and method for early warning based on Fibre Optical Sensor |
| CN114234056A (en) * | 2021-11-30 | 2022-03-25 | 武汉理工大学 | Distributed optical fiber acoustic wave sensing pipeline leakage monitoring system and method |
| CN114234056B (en) * | 2021-11-30 | 2023-11-10 | 武汉理工大学 | Distributed optical fiber acoustic wave sensing pipeline leakage monitoring system and method |
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