WO2022176047A1 - 電柱位置特定方法及び架空光ファイバケーブルの状態推定方法 - Google Patents
電柱位置特定方法及び架空光ファイバケーブルの状態推定方法 Download PDFInfo
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- WO2022176047A1 WO2022176047A1 PCT/JP2021/005852 JP2021005852W WO2022176047A1 WO 2022176047 A1 WO2022176047 A1 WO 2022176047A1 JP 2021005852 W JP2021005852 W JP 2021005852W WO 2022176047 A1 WO2022176047 A1 WO 2022176047A1
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- Prior art keywords
- optical fiber
- vibration
- utility pole
- vibration distribution
- fiber cable
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- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000000835 fiber Substances 0.000 title abstract description 7
- 239000013307 optical fiber Substances 0.000 claims abstract description 95
- 238000000691 measurement method Methods 0.000 claims abstract description 13
- 239000000126 substance Substances 0.000 claims 1
- 238000005259 measurement Methods 0.000 description 12
- 230000003287 optical effect Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 230000003595 spectral effect Effects 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 230000002159 abnormal effect Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 230000001427 coherent effect Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000000253 optical time-domain reflectometry Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/14—Measuring arrangements characterised by the use of optical techniques for measuring distance or clearance between spaced objects or spaced apertures
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
-
- 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
- G01D5/35338—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 other arrangements than interferometer arrangements
- G01D5/35354—Sensor working in reflection
- G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/46—Processes or apparatus adapted for installing or repairing optical fibres or optical cables
- G02B6/48—Overhead installation
- G02B6/483—Installation of aerial type
Definitions
- the present invention relates to a method for identifying the position of a utility pole and a method for estimating the state of an overhead optical fiber cable using an optical fiber vibration distribution measurement method.
- Non-Patent Document 1 A method of intentionally applying vibration to an optical fiber cable has been proposed in order to compare the installation position (see, for example, Non-Patent Document 1 and Non-Patent Document 2).
- the methods described in Non-Patent Literature 1 and Non-Patent Literature 2 apply vibration to an optical fiber cable or the like, and measure the temporal change of scattered light at a specific position by a light pulse test method.
- an object of the present disclosure is to provide a method for remotely identifying the position of a utility pole and estimating the state of an overhead optical fiber cable.
- an optical fiber vibration distribution measurement method (DAS: Distributed Acoustic Sensing) is used to identify the utility pole position from the vibration distribution pattern with respect to the optical fiber distance. , to estimate the condition of the aerial fiber optic cable.
- DAS Distributed Acoustic Sensing
- the utility pole position identification method of the present disclosure is based on the vibration distribution pattern obtained by sequentially accumulating the amount of strain with respect to the distance of the optical fiber measured by the optical fiber vibration distribution measurement method. It is characterized by specifying that
- the method for estimating the state of an aerial optical fiber cable of the present disclosure is based on a vibration distribution pattern obtained by sequentially accumulating the amount of strain with respect to the optical fiber distance in the utility pole span measured by the optical fiber vibration distribution measurement method. propagates along the optical fiber and the amplitude of the vibration is uniform, it is determined that the optical fiber cable is normal.
- the method for estimating the state of an aerial optical fiber cable of the present disclosure is based on a vibration distribution pattern obtained by sequentially accumulating the amount of strain with respect to the optical fiber distance in the utility pole span measured by the optical fiber vibration distribution measurement method. is propagated along the optical fiber and the amplitude of the vibration is not uniform, it is determined that the optical fiber cable has a load due to deposits.
- the method for estimating the state of an aerial optical fiber cable of the present disclosure is based on a vibration distribution pattern obtained by sequentially accumulating the amount of strain with respect to the optical fiber distance in the utility pole span measured by the optical fiber vibration distribution measurement method. is stopped or reduced in the middle of the optical fiber, it is determined that an obstacle on the ground is in contact with the optical fiber cable.
- FIG. 4 is a diagram showing a vibration distribution pattern of an optical fiber
- FIG. 4 is a diagram showing a vibration distribution pattern of an optical fiber
- FIG. 4 is a diagram showing a vibration distribution pattern of an optical fiber
- FIG. 4 is a diagram showing a vibration distribution pattern of an optical fiber
- FIG. 1 is a schematic diagram showing how a DAS is used to specify the position of a utility pole from the vibration distribution pattern with respect to the optical fiber distance, and how an aerial optical fiber cable is installed.
- An optical signal is input to an optical cable from an optical fiber vibration distribution measuring device installed in a communication building.
- An optical signal propagates from an optical fiber cable laid underground to an optical fiber cable laid overhead. Rayleigh scattering is induced in the optical fiber while propagating, and part of the Rayleigh scattered light scattered toward the optical fiber vibration distribution measuring apparatus returns as backscattered light.
- OTDR Optical Time Domain Reflectometer
- OFDR Optical Frequency Domain Reflectometer
- the vibration frequency of an overhead optical fiber cable is 10 Hz or less and the wavelength is about 2 m.
- the measurement performance required for the backscattered light measuring means is a sampling frequency of 20 Hz or more and a spatial resolution of about 1 m.
- C-OTDR Coherent OTDR
- OFDR Optical Frequency Domain Reflectometer
- the DAS of this embodiment uses an OFDR (Optical Frequency Domain Reflectometer) as backscattered light measuring means to measure the backscattered light waveform with respect to the distance Z of the optical fiber cable.
- OFDR Optical Frequency Domain Reflectometer
- FIG. 2 first, the backscattered light intensity with respect to the distance of the optical fiber cable, which is the "reference measurement”, is acquired, and the "first measurement”, “second measurement”, ... " The backscattered light waveforms for the n-th measurement are sequentially acquired.
- the waveforms at the distance between Z1 and Z2 are subjected to spectrum analysis (Fourier transform) and the spectrum shift is calculated to obtain the spectrum waveforms shown in FIG.
- the spectrum obtained during the reference measurement is used as a reference waveform, the cross-correlation with the spectrum at each time is calculated, and the spectral shift that gives the cross-correlation peak is calculated.
- spectral shifts are calculated in the order of "reference measurement”, "first measurement”, and "second measurement”.
- the spectral shift ⁇ is represented by the following equation by modifying the equation (8) of Non-Patent Document 3.
- ⁇ ⁇ 0.78* ⁇ * ⁇ 0 (1)
- ⁇ is the amount of distortion
- ⁇ 0 is the center frequency of the probe light.
- the amount of spectral shift with respect to distance is represented by black and white shading, and by accumulating sequentially for each time, the vibration distribution pattern of the optical fiber as shown in Fig. 4 can be obtained.
- a portion with positive strain indicates that the optical fiber is stretched, and a portion with negative strain indicates that the optical fiber is compressed.
- positive distortion portions are represented by white and negative distortion portions are represented by black. It may also be represented by shades of different colors.
- An overhead optical fiber cable can be regarded as a string that vibrates uniquely for each utility pole span.
- the wind-induced vibration propagates through the utility pole span over time, and the amplitude and propagation speed of the vibration differ from one utility pole span to another. Therefore, it was found that each utility pole span has a different vibration pattern. Conversely, it can be determined that the boundary area of the vibration pattern in FIG. 4 is the utility pole position.
- FIGS. 5, 6, and 7 show examples of optical fiber vibration distribution patterns in which the amount of strain with respect to the optical fiber distance within the utility pole span measured by the DAS is sequentially accumulated for each time.
- An overhead optical fiber cable can be regarded as a string that vibrates for each utility pole span, and by measuring the vibration pattern, it is possible to estimate the laying state of the optical fiber cable.
- Fig. 5 shows the vibration pattern when the optical fiber cable is normal.
- the wind-induced vibration propagates along the overhead fiber optic cable and within the utility pole span over time, where the amplitude of the vibration is uniform within the utility pole span.
- Fig. 6 shows the vibration pattern when there is a load due to the attached matter on the optical fiber cable.
- wind-generated vibrations propagate along the overhead fiber optic cable and within the utility pole span over time.
- the amplitude of vibration is large at the load point of the deposit. That is, it can be seen that the amplitude of vibration is not uniform within the utility pole span.
- Fig. 7 shows the vibration pattern when an obstacle on the ground, such as a tree, is in contact with the optical fiber cable. It can be seen from FIG. 7 that the wind-generated vibration propagates between the utility pole and the ground obstacle, but the vibration stops or reduces at the ground obstacle. That is, the vibration stops or reduces partway through the pole span and does not propagate along the fiber optic cable.
- FIG. 8 shows a flow chart for judging whether the optical fiber cable is normal or abnormal.
- DAS Distributed Acoustic Sensor
- the optical fiber cable is normal (S15 ).
- Vibration propagates along the overhead optical fiber cable within the utility pole span (Yes in S13), and when the amplitude of the vibration is not uniform within the utility pole span (No in S14), the optical fiber cable is loaded with deposits. (S16). Furthermore, it is possible to specify that there is a deposit at the point of discontinuity in the vibration amplitude.
- the optical fiber cable When the vibration propagates between the utility pole and the ground obstacle, but stops or shrinks in the middle of the utility pole span and does not propagate along the optical fiber cable (No in S13), the optical fiber cable is on the ground. It is estimated that it is in contact with an obstacle (S17). Furthermore, it can be determined that the fiber optic cable is in contact with the ground obstacle at the point of vibration stoppage or reduction.
- the position of the utility pole can be remotely specified, It is possible to estimate the state of the overhead optical fiber cable and identify the location of the fault.
- DAS Distributed Acoustic Sensor
- This disclosure can be applied to the information and communications industry.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Locating Faults (AREA)
Abstract
Description
光ファイバ振動分布測定方法(DAS:Distributed Acoustic Sensor)を利用した電柱位置特定方法を説明する。DASを利用して、光ファイバ距離に対する振動分布パターンから電柱位置を特定したり、架空光ファイバケーブルの架設状態を示す模式図を図1に示す。通信ビルに設置された光ファイバ振動分布測定装置から、光信号を光ケーブルに入力する。光信号は、地下に敷設された光ファイバケーブルから架空に敷設された光ファイバケーブルを伝搬する。伝搬しながら光ファイバ内でレイリー散乱を誘導し、そのうち、光ファイバ振動分布測定装置側に散乱したレイリー散乱光の一部が後方散乱光として戻ってくる。
Δν=-0.78*ε*ν0 (1)
ここで、εは歪量、ν0はプローブ光の中心周波数を表す。
光ファイバ振動分布測定方法(DAS)を利用した架空光ファイバケーブルの状態推定方法を説明する。DASで測定した電柱スパン内の光ファイバ距離に対する歪量を時間ごとに順次積み上げた光ファイバの振動分布パターンの例を図5、図6及び図7に示す。架空光ファイバケーブルは、電柱スパンごとに振動する弦とみなすことができ、振動パターンを測定することで、光ファイバケーブルの敷設状態を推定することができる。
Claims (4)
- 光ファイバ振動分布測定方法で測定した光ファイバの距離に対する歪量を時間ごとに順次積み上げた振動分布パターンから、振動分布の境界領域が電柱位置であると特定する電柱位置特定方法。
- 光ファイバ振動分布測定方法で測定した電柱スパン内の光ファイバ距離に対する歪量を時間ごとに順次積み上げた振動分布パターンから、振動が光ファイバに沿って伝搬し、かつ振動の振幅が一様であれば、光ファイバケーブルが正常であると判断する架空光ファイバケーブルの状態推定方法。
- 光ファイバ振動分布測定方法で測定した電柱スパン内の光ファイバ距離に対する歪量を時間ごとに順次積み上げた振動分布パターンから、振動が光ファイバに沿って伝搬し、かつ振動の振幅が一様でなければ、光ファイバケーブルに付着物による荷重があると判断する架空光ファイバケーブルの状態推定方法。
- 光ファイバ振動分布測定方法で測定した電柱スパン内の光ファイバ距離に対する歪量を時間ごとに順次積み上げた振動分布パターンから、振動が光ファイバの途中で停止又は縮小していれば、光ファイバケーブルに地上障害物が接触していると判断する架空光ファイバケーブルの状態推定方法。
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JP2023500173A JP7491458B2 (ja) | 2021-02-17 | 電柱位置特定方法及び架空光ファイバケーブルの状態推定方法 | |
CN202180093496.XA CN116917703A (zh) | 2021-02-17 | 2021-02-17 | 电线杆位置确定方法和架空光缆的状态推定方法 |
PCT/JP2021/005852 WO2022176047A1 (ja) | 2021-02-17 | 2021-02-17 | 電柱位置特定方法及び架空光ファイバケーブルの状態推定方法 |
US18/275,726 US20240118126A1 (en) | 2021-02-17 | 2021-02-17 | Positioning method of electric pole and estimating method of the state of overhead optical fiber cable |
EP21926487.6A EP4296633A1 (en) | 2021-02-17 | 2021-02-17 | Utility pole position specification method and aerial fiber optic cable state estimation method |
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WO2024057492A1 (ja) * | 2022-09-15 | 2024-03-21 | 日本電信電話株式会社 | 振動分布波形から電柱位置を特定する方法 |
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- 2021-02-17 EP EP21926487.6A patent/EP4296633A1/en active Pending
- 2021-02-17 US US18/275,726 patent/US20240118126A1/en active Pending
- 2021-02-17 WO PCT/JP2021/005852 patent/WO2022176047A1/ja active Application Filing
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