Optical cable unit monitoring device and optical cable unit monitoring method

Abstract

An optical cable unit monitoring device and an optical cable unit monitoring method are provided that suitably detect abnormal locations in an optical cable unit due to breakage of a support wire. [Solution] A monitoring device 600 for an optical cable unit in which an optical cable is supported by a support wire, comprising a distortion waveform acquisition unit 620 that acquires a distortion waveform in the monitored section of the optical cable unit, and an abnormality point acquisition unit 650 that acquires, based on the distortion waveform, an abnormal point in the optical cable unit in the monitored section of the optical cable unit due to a break in the support wire that supports the optical cable.

Description

[Technical Field]

[0001] The present invention relates to an optical cable unit monitoring device and an optical cable unit monitoring method. [Background technology]

[0002] Patent Document 1 describes an optical fiber cable monitoring method for monitoring multiple specific points arranged along the length of an optical fiber cable. This optical fiber cable monitoring method includes a distance information acquisition procedure, a linking procedure, an abnormality detection procedure, and a position acquisition procedure. The distance information acquisition procedure involves optical measurement, which propagates measurement light to acquire information on the distance of the optical fiber cable, to acquire distance information for specific points on the optical fiber cable. The linking procedure involves using the previously acquired order and geographical location information of the specific points to link the geographical location information and distance information for each specific point based on the order of the specific points. The abnormality detection procedure involves optical monitoring, which is less sensitive than optical measurement and propagates monitoring light to acquire information on the distance of the optical fiber cable, to detect distance information for abnormal points on the optical fiber cable that occur on the optical fiber cable. The position acquisition procedure involves using the geographical location information and distance information of the specific points linked in the linking procedure to acquire geographical location information for the specific points corresponding to the abnormal points from the distance information of the abnormal points detected in the abnormality detection procedure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-152630 A Summary of the Invention [Problem to be solved by the invention]

[0004] Known optical cable units include those in which an optical cable is supported on a support wire (self-supporting cables in which the optical cable and support wire are integrated, and optical cable units in which a longitudinally extending support wire and an optical cable are connected at the neck).

[0005] In such optical cable units, abnormalities in the optical cable unit due to breakage of the support wire (for example, even if the optical cable is intact, if the support wire breaks, the optical cable loses its supporting force and is pulled, eventually causing the optical cable to break as well) are a serious problem.

[0006] In this regard, conventional technologies including the above-mentioned Patent Document 1 are unable to effectively detect abnormal portions of an optical cable unit caused by breakage of a support wire. For example, it is unable to detect breakage of a support wire early and with high accuracy before it has a detrimental effect (chain breakage) on the optical cable.

[0007] The present invention has been made in consideration of the above-mentioned concerns, and aims to provide an optical cable unit monitoring device and an optical cable unit monitoring method that can effectively detect abnormal areas in an optical cable unit caused by a break in a support wire. [Means for solving the problem]

[0008] The optical cable unit monitoring device of this embodiment is an optical cable unit monitoring device in which an optical cable is supported by a support wire, and includes: a distortion waveform acquiring unit that acquires a distortion waveform of a monitored section of the optical cable unit; a disturbance waveform acquisition unit that acquires a disturbance waveform of the monitoring target section of the optical cable unit; and a corrected distortion waveform acquisition unit that acquires a corrected distortion waveform obtained by correcting the distortion waveform based on the disturbance waveform. The aforementioned correction The optical cable unit is characterized by having an abnormality location acquisition unit that acquires an abnormality location of the optical cable unit caused by a break in the support wire in the monitored section of the optical cable unit based on the distorted waveform.

[0009] The optical cable unit monitoring method of this embodiment is a method for monitoring an optical cable unit in which an optical cable is supported on a support wire, and includes: of acquiring a distortion waveform; a step of acquiring a disturbance waveform of the monitored section of the optical cable unit; and a step of acquiring a corrected distorted waveform by correcting the distorted waveform based on the disturbance waveform; The aforementioned correction Based on the distorted waveform, in the monitored section of the optical cable unit ,beforeand acquiring an abnormality location in the optical cable unit due to a break in the support wire. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an optical cable unit monitoring device and an optical cable unit monitoring method that can suitably detect an abnormal portion of an optical cable unit caused by a break in a support wire. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a schematic configuration of an FTTH system. [Figure 2] FIG. 1 is a diagram illustrating an example of a state in which an abnormality occurs in an FTTH system. [Figure 3] 10A and 10B are diagrams illustrating an example of a mechanism by which distortion occurs due to breakage of a support wire of an optical cable unit. [Figure 4] FIG. 1 is a diagram illustrating an example of a cross-sectional structure of an optical cable. [Figure 5] FIG. 1 is a diagram illustrating an example of a schematic configuration of a monitoring device for an optical cable unit. [Figure 6] 10A and 10B are diagrams illustrating an example of disturbance factors in a monitored section of an optical cable unit. [Figure 7] 10A and 10B are diagrams illustrating an example of processing performed by a corrected distortion waveform acquiring unit and an abnormality portion acquiring unit. [Figure 8] FIG. 10 is a diagram illustrating an example of processing performed by an abnormality point acquisition unit. [Figure 9] 10A and 10B are diagrams showing an example of the amount of change in strain before and after the breakage of a support line in the presence and absence of a disturbance factor. [Figure 10] 1A to 1C are diagrams illustrating steps of a method for monitoring an optical cable unit. DETAILED DESCRIPTION OF THE INVENTION

[0012] The optical cable unit monitoring device and the optical cable unit monitoring method of this embodiment will be described below. The optical cable unit monitoring device and the optical cable unit monitoring method of this embodiment are applied to, for example, optical line maintenance work and are used to identify abnormalities (fault locations, fault locations) in the optical line.

[0013] Furthermore, the optical cable unit monitoring device and optical cable unit monitoring method of this embodiment focus on the fact that, for example, when a support wire of an overhead optical cable breaks, the optical cable loses its supporting force and is pulled toward the utility pole, and by measuring and analyzing the strain occurring in the optical fiber, the fault location can be identified non-destructively. In particular, the distortion waveform is Fourier transformed to remove (filter) the disturbance waveform from the Fourier transformed distortion waveform to obtain a cleared waveform, and the cleared waveform is then inverse Fourier transformed to obtain a corrected distortion waveform, and based on the corrected distortion waveform, only the distortion change due to the support wire break can be extracted and the fault location can be identified.

[0014] <Conventional technical issues> Overhead optical cables laid between utility poles can be damaged by strong winds or contact with trees. For example, in cables where the optical cable and support wire are integrated, such as self-supporting cables, the support wire may break. If this condition is left unattended, the optical cable may not be able to withstand the tension and may eventually break, which could have a serious impact on communication services.

[0015] Conventionally, optical cable damage has been identified by visual inspection or by measuring the light intensity using an optical time domain reflectometer (OTDR). However, visual inspection requires manual intervention, making it difficult to comprehensively identify damage and time-consuming. An OTDR is installed in a terminal facility or a central office, sends out optical pulses, and measures the intensity change of backscattered light generated within the optical fiber to measure the distance to the fault and identify the fault. While it can identify extreme bends and breaks that cause optical loss, it is difficult to detect precursors to a break. Therefore, there is no technology that effectively identifies damage to overhead optical cables, particularly breaks in support wires. Therefore, the OTDR is limited to identifying the location of a break in the optical cable after a break in the support wire has occurred.

[0016] As such, technology that can remotely and comprehensively identify breaks in support wires that could cause optical cable breaks is important for rapid recovery after disasters such as typhoons, and there is a strong demand for such technology, but there is no conventional technology that can meet this demand.

[0017] <Basic technical concept of this embodiment> The inventors recognized the above-mentioned problems as important technical challenges and came up with the idea of ​​an optical cable unit monitoring device and an optical cable unit monitoring method that can effectively detect abnormal areas in an optical cable unit caused by a break in a support wire in an optical cable unit (e.g., an aerial optical cable) in which an optical cable is supported by a support wire.

[0018] More specifically, optical fiber strain distribution sensing is a technology that measures the distribution of strain that occurs in optical fibers.By focusing on the fact that when a support wire breaks, the optical cable loses its supporting force and is pulled toward the utility pole, and measuring the strain that occurs there, it is possible to effectively detect abnormal areas in the optical cable unit caused by a support wire break.

[0019] In the present embodiment, a monitoring device and a monitoring method for an optical cable unit in which an optical cable is supported by a support wire are disclosed. In a distortion waveform acquisition step, a distortion waveform acquisition unit acquires a distortion waveform of a monitored section of the optical cable unit. In the abnormality location acquisition step, an abnormality location of the optical cable unit due to a break in the support wire is acquired based on the distortion waveform.

[0020] This makes it possible to suitably detect an abnormality in the optical cable unit due to a break in the support wire. That is, by detecting the precursor to a break in the support wire leading to a break in the optical cable, it is possible to suitably detect an abnormality in the optical cable unit at a stage before a chain reaction of breaks occurs in the optical cable (at a stage when the optical cable is functioning normally), and to carry out appropriate repairs or treatment.

[0021] <Specific embodiment> First Embodiment 1 is a diagram illustrating an example of a schematic configuration of an FTTH (Fiber To The Home) system 100. The FTTH system 100 includes a terminal (sometimes referred to as terminal equipment) 200, an accommodation station 300, and an optical cable unit 400 that connects the terminal equipment 200 and the accommodation station 300.

[0022] The terminal facility 200 is a general term for wiring facilities and terminal devices installed at installation locations such as detached houses, apartment buildings, and offices. The accommodation station 300 is a communication station for an optical line on the provider side that supplies communication light to the terminal 200 via an optical cable unit 400. In FIG. 1, each terminal 200 and the accommodation station 300 are shown connected via an optical cable unit 400, but in reality, multiple (many) terminals 200 are connected to one accommodation station 300 via the optical cable unit 400. Furthermore, in FIG. 1, three relay units (e.g., utility poles) 500A, 500B, and 500C are shown as examples at intermediate positions between the terminal 200 and the accommodation station 300 to which the optical cable unit 400 is connected.

[0023] 1, the section between the terminal 200 and the repeater unit 500A, the section between the repeater unit 500A and the repeater unit 500B, the section between the repeater unit 500B and the repeater unit 500C, and the section between the repeater unit 500C and the station 300 can each be the "section to be monitored by the optical cable unit 400." Of course, the entire section between the terminal 200 and the station 300 may also be the "section to be monitored by the optical cable unit 400."

[0024] FIG. 2 is a diagram illustrating an example of a state in which an abnormality (failure, fault) occurs in the FTTH system 100. The optical cable unit 400 is an optical cable 400Y supported by a support wire 400X (a self-supporting cable in which the optical cable 400Y and the support wire 400X are integrated). More specifically, the support wire 400X and the optical cable 400Y extend side by side in the longitudinal direction, and the support wire 400X and the optical cable 400Y are connected in the transverse direction by neck portions 400Z provided intermittently in the longitudinal direction. The optical cable unit 400 may also be referred to as an aerial optical cable or an aerial optical cable unit. A monitoring device 600 is connected to the optical cable unit 400 to identify (detect) the occurrence of an abnormality (failure, fault) in the optical cable unit 400. In the example of FIG. 2, the monitoring device 600 for the optical cable unit 400 is depicted as a simplified block diagram to facilitate understanding of the invention.

[0025] 2, the optical cable unit 400 comes into contact with a tree between the repeater section 500A and the repeater section 500B (the section monitored by the optical cable unit 400), causing a portion of the support wire 400X to break. As a result, the optical cable 400Y, which is separated from the support wire 400X, loses its supporting force and is pulled to both sides between the repeater section 500A and the repeater section 500B.

[0026] 3A and 3B are diagrams showing an example of a strain generation mechanism due to breakage of the support wire 400X of the optical cable unit 400. FIG. 3A shows a normal state in which the support wire 400X is not broken, and FIG. 3B shows an abnormal state in which the support wire 400X is broken. In the normal state of FIG. 3A, tension is always applied to the support wire 400X, and the optical cable 400Y supported by the support wire 400X is in a free state (a state with moderate slack), and no stretch (strain) occurs in the optical cable 400Y. In contrast, when a portion of the support wire 400X breaks, the abnormal state of FIG. 3B occurs, in which the optical cable 400Y loses its supporting force and is pulled by the broken support wire 400X, causing stretch (strain) in the optical cable 400Y.

[0027] FIG. 4 is a diagram showing an example of the cross-sectional structure of an optical cable 400Y. The optical cable 400Y has multiple optical fibers built in. As shown in FIG. 4, the optical cable 400Y may be a spacer-type optical cable. In the example of FIG. 4, the optical cable 400Y has a spacer 410 with multiple spiral slots 420 formed on its outer periphery, and multiple stacked optical fiber bundles (tape-shaped optical fibers) 430, each of which has multiple (e.g., four) optical fibers 430a arranged in parallel, are housed in each slot 420. A tension member 440 is provided at the central axis position of the spacer 410, and a water stop tape 450 and an outer jacket (sheath) 460 are sequentially provided around the spacer 410. Note that the optical cable 400Y is not limited to the spacer-type.

[0028] 5 is a diagram showing an example of the schematic configuration of an optical cable unit monitoring device (hereinafter sometimes simply referred to as "monitoring device") 600. The monitoring device 600 has a monitoring section identification unit 610, a distorted waveform acquisition unit 620, a disturbance waveform acquisition unit 630, a corrected distorted waveform acquisition unit 640, and an abnormality location acquisition unit 650.

[0029] The optical cable unit monitoring method of this embodiment is realized, for example, by each component (including a computer) of the monitoring device 600 executing (causing each component to execute) various processing steps. The monitoring device 600 may be read as a distortion measuring device and a distortion analyzing device, and can be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network.

[0030] The monitoring section specifying unit 610 specifies (acquires, measures, detects) a monitoring section (an estimated abnormality section, an estimated failure section) of the optical cable unit 400 between the terminal equipment 200 and the accommodating station 300. There is a degree of freedom in how the monitoring section specifying unit 610 specifies the monitoring section of the optical cable unit 400, and various design modifications are possible. For example, the monitoring section specifying unit 610 can specify the entire section between the terminal equipment 200 and the accommodating station 300 as the monitoring section of the optical cable unit 400. Alternatively, the monitoring section specifying unit 610 may specify the monitoring section of the optical cable unit 400 using an arbitrary range specified by the user. In the following description, it is assumed that the entire section between the terminal equipment 200 and the accommodating station 300 is the monitoring section of the optical cable unit 400.

[0031] The distortion waveform acquiring unit 620 acquires a distortion waveform of the monitored section (the entire section between the terminal 200 and the exchange 300) of the optical cable unit 400. The distortion waveform acquiring unit 620 may be configured, for example, by an optical fiber strain distribution measuring device (an optical fiber distributed sensing device using time domain measurement technology).

[0032] The distortion waveform acquisition unit 620 may acquire a distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the exchange 300) using a BOTDR (Brillouin Optical Time Domain Reflectometer), which measures frequency changes in Brillouin scattered light. The BOTDR acquires distortion caused by temperature changes or stress applied to the optical fiber used as a sensor as continuous data over a predetermined distance (e.g., several tens of kilometers) in the longitudinal direction of the sensor optical fiber. The BOTDR can acquire data two-dimensionally (on a surface) or three-dimensionally (stereoscopically) depending on the installation method of the sensor optical fiber. Light incident on an optical fiber generates various types of scattered light as it travels through the optical fiber. The BOTDR can measure the frequency shift of Brillouin scattered light, which depends on distortion and temperature changes, from one end of the scattered light.

[0033] By checking the characteristics of the optical fiber to be used for measurement in advance and using the strain and temperature coefficients of the optical fiber in the frequency shift of the measured Brillouin scattered light, it is possible to measure changes in strain and temperature. Because the speed of light propagating through an optical fiber is constant, it is possible to identify the position in the optical fiber where the Brillouin scattered light was generated by measuring the elapsed time from when a pulse of light is input until the Brillouin scattered light returns. Based on the frequency shift distribution of the Brillouin scattered light processed in the time and wavelength domains, strain and temperature data along the optical fiber can be obtained.

[0034] In addition to the above-mentioned BOTDR, the distortion waveform acquisition unit 620 may also combine a COTDR (Coherent Optical Time Domain Reflectometer) that measures phase changes in Rayleigh scattered light, a TW-COTDR (Tunable Wavelength Coherent Optical Time Domain Reflectometer) that measures frequency changes in Rayleigh scattering, and a ROTDR (Raman Optical Time Domain Reflectometer) that measures intensity changes in Raman scattered light. These measurement methods are based on the OTDR as their fundamental principle, but differ in the scattered light, wavelength, and detection method they measure.

[0035] The distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300) acquired by the distortion waveform acquisition unit 620 has the longitudinal position of the optical cable unit 400 (the distance from the reference position of the optical cable unit 400) plotted on the horizontal axis and the amount of distortion change of the optical cable unit 400 plotted on the vertical axis.

[0036] Furthermore, as will be described later, the distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300) acquired by the distortion waveform acquisition unit 620 may include, as distortion change amounts on the vertical axis, distortion change amounts caused by abnormalities in the optical cable unit 400 (e.g., breakage of the support wire 400X) and distortion change amounts based on disturbance factors (e.g., environmental information such as temperature information, sunshine information, humidity information, wind information, rain information, etc.) in the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300).

[0037] The disturbance waveform acquiring unit 630 acquires a disturbance waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300). The disturbance waveform acquired by the disturbance waveform acquiring unit 630 has the longitudinal position of the optical cable unit 400 (the distance from the reference position of the optical cable unit 400) plotted on the horizontal axis, and the amount of change in distortion due to the disturbance factor of the monitored section of the optical cable unit 400 plotted on the vertical axis.

[0038] The disturbance waveform acquisition unit 630 may acquire the disturbance waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) in accordance with the overall distortion of the optical cable unit 400 due to the installation environment of the optical cable unit 400 (temperature, sunlight, humidity, wind, rain, etc.).

[0039] The disturbance waveform acquiring unit 630 may have a temperature sensor that acquires temperature information, a sunshine sensor that acquires sunshine information, a humidity sensor that acquires humidity information, a wind sensor that acquires wind information, and a rain sensor that acquires rain information in the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodation station 300). The disturbance waveform acquiring unit 630 may acquire the disturbance waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodation station 300) based on the output of each of these sensors.

[0040] The temperature sensor may be, for example, a resistance temperature detector, a thermocouple, a radiation thermometer, an alcohol thermometer, a bimetal thermometer, a pressure thermometer, or a thermistor thermometer. The sunshine sensor may be, for example, a pyranometer or a direct pyranometer. The humidity sensor may be, for example, an electric (electronic) humidity sensor, a wet / dry bulb humidity sensor (wet / dry bulb hygrometer), an electrolyte humidity sensor, a ceramic humidity sensor, or a thermal conduction humidity sensor. The wind sensor may be, for example, a rotary type (cup type or windmill type), a wind pressure type (pitot tube type), an ultrasonic type, or a thermal type (hot wire type). The rain sensor may be, for example, a type that collects rain in a bucket and measures it, or an optical type or a capacitance type.

[0041] The overall distortion of the optical cable unit 400 due to the installation environment (temperature, sunlight, humidity, wind, rain, etc.) of the optical cable unit 400 usually fluctuates from moment to moment. For this reason, it is preferable that the disturbance waveform acquisition unit 630 acquires the disturbance waveform as a preliminary measurement each time the optical cable unit 400 is inspected or repaired, and updates the waveform at an appropriate timing.

[0042] The disturbance waveform acquisition unit 630 may, for example, use input / output conversion from disturbance factors to disturbance waveforms using machine learning to acquire disturbance waveforms for the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) based on environmental information (temperature information, sunshine information, humidity information, wind information, and rain information) acquired as disturbance factors.

[0043] Fig. 6 is a diagram showing an example of disturbance factors in the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300). In Fig. 6, the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) is divided into divided monitored sections 400-1, 400-2, ..., 400-N (N is a natural number equal to or greater than 2). Then, for each of the divided monitored sections 400-1 to 400-N, temperature information from a temperature sensor, sunshine information from a sunshine sensor, humidity information from a humidity sensor, wind information from a wind sensor, and rain information from a rain sensor are acquired (measured).

[0044] As a calibration process, the disturbance waveform acquisition unit 630 stores a reference waveform in a reference state in which there are no distortion factors or disturbance factors in the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodation station 300). This reference waveform may be, for example, a linear waveform in which the horizontal axis represents the longitudinal position of the optical cable unit 400 (the distance from the reference position of the optical cable unit 400) and the vertical axis represents the amount of change in distortion of the optical cable unit 400, and the vertical axis always remains zero or a constant value.

[0045] The disturbance waveform acquisition unit 630 performs calculations with reference to the above-mentioned reference waveform, using disturbance factors (environmental information including temperature information, sunshine information, humidity information, wind information, and rain information) of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) as input parameters, and the disturbance waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) as output parameters.

[0046] The processing will be explained as follows based on the divided monitoring target sections 400-1 to 400-N illustrated in Fig. 6. The disturbance factors (environmental information including temperature information, sunshine information, humidity information, wind information, and rain information) acquired for the divided monitoring target sections 400-1 to 400-N change from moment to moment and may differ for each divided monitoring target section.

[0047] For example, when a set of temperature information, sunshine information, humidity information, wind information, and rainfall information is input for divided monitoring section 400-1, a distortion change amount 1 for divided monitoring section 400-1 is calculated as an output parameter based on that input set. Similarly, when a different set of temperature information, sunshine information, humidity information, wind information, and rainfall information is input for divided monitoring section 400-2, a distortion change amount 2 for divided monitoring section 400-2 is calculated as an output parameter based on that input set. Calculations like this are continued, and when yet another set of temperature information, sunshine information, humidity information, wind information, and rainfall information is input for divided monitoring section 400-N, a distortion change amount N for divided monitoring section 400-N is calculated as an output parameter based on that input set. Then, an approximate straight line connecting the distortion change amounts 1 to N calculated for the divided monitoring target sections 400-1 to 400-N is calculated as the disturbance waveform for the monitoring target section (all sections between the terminal 200 and the accommodation station 300) of the optical cable unit 400. The calculation of the approximate straight line can be performed using, for example, the least squares method.

[0048] The algorithm by which the disturbance waveform acquisition unit 630 calculates output parameters from input parameters has a degree of freedom and various design modifications are possible, but for example, estimation of a disturbance waveform from a disturbance factor by machine learning can be used. The disturbance waveform acquisition unit 630 may cooperate with an AI (Artificial Intelligence) including a large-scale language model (not shown), a generative AI, or the like, to perform input / output conversion from a disturbance factor to a disturbance waveform that will be acquired, calculated, and estimated by machine learning in the future, based on an input / output conversion model from a disturbance factor to a disturbance waveform that has been acquired, calculated, estimated, and accumulated in the past by machine learning.

[0049] The machine learning model used in this embodiment may use linear regression with distortion as the objective variable and each sensor data as the explanatory variable. As an example, in the following formula, Y represents distortion, which is the objective variable, and X1, X2, . . . , Xp (p is a natural number of 2 or more) represent each sensor data (e.g., temperature information, sunshine information, humidity information, wind information, rain information, . . .) which is the explanatory variable. By performing regression analysis for each divided monitoring target section 400-1 to 400-N to obtain each of the constants β0, β1, β2, . . . , βp (p is a natural number of 2 or more), and by obtaining an additional constant ε for the machine learning model, it is possible to predict distortion with high accuracy. Y=β0+β1·X1+β2·X2+···+βp·Xp+ε

[0050] Alternatively, the disturbance waveform acquisition unit 630 may obtain distortion change amount 1 to distortion change amount N for each of the divided monitored sections 400-1 to 400-N by substituting the relevant information into an arithmetic expression or calculation table with temperature information, sunshine information, humidity information, wind information, and rain information as input parameters, and acquire an approximate straight line connecting distortion change amount 1 to distortion change amount N as the disturbance waveform for the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300).

[0051] The corrected distortion waveform acquisition unit 640 acquires a corrected distortion waveform by correcting the distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) acquired by the distortion waveform acquisition unit 620, based on the disturbance waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) acquired by the disturbance waveform acquisition unit 630.

[0052] The corrected distortion waveform acquisition unit 640 performs a Fourier transform on the distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) acquired by the distortion waveform acquisition unit 620, acquires a removed waveform by removing (filtering) the disturbance waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300) acquired by the disturbance waveform acquisition unit 630 from the distorted waveform after the Fourier transform, and acquires a corrected distortion waveform by performing an inverse Fourier transform on the removed waveform.

[0053] The corrected distortion waveform acquisition unit 640 may acquire a corrected distortion waveform by correcting the distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300) acquired by the distortion waveform acquisition unit 620 without using the disturbance waveform (not based on the disturbance waveform). For example, the corrected distortion waveform acquisition unit 640 may acquire a corrected distortion waveform by performing a Fourier transform on the distortion waveform of the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300) acquired by the distortion waveform acquisition unit 620, and then cutting (filtering) low-frequency components from the Fourier-transformed distortion waveform. Furthermore, if the change in the disturbance waveform is gradual, the change in the disturbance waveform can be patterned, or the change in the disturbance waveform can be ignored, it is also possible to predict the disturbance waveform, apply this predicted disturbance waveform to the distorted waveform to correct it, and then perform a Fourier transform and filtering.

[0054] Based on the corrected distortion waveform acquired by the corrected distortion waveform acquisition unit 640, the abnormality location acquisition unit 650 acquires abnormal locations in the optical cable unit 400 caused by breakage of the support wire 400X in the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the accommodating station 300).

[0055] The abnormality location acquisition unit 650 acquires, within the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300), a location where the amplitude of the corrected distortion waveform acquired by the corrected distortion waveform acquisition unit 640 is equal to or greater than a threshold, as an abnormality location of the optical cable unit 400 caused by a break in the support wire 400X.

[0056] The abnormality location acquisition unit 650 defines a plurality of divided monitoring sections (divided window sections) by dividing the monitored section of the optical cable unit 400 (the entire section between the terminal 200 and the receiving station 300), and for each divided monitoring section (each divided window section), calculates a divided abnormality score by adding up the average value and standard deviation of the corrected distortion waveform, and acquires the divided monitoring section (divided window section) among the divided monitoring sections (each divided window section) whose divided abnormality score is equal to or greater than the threshold score as the divided abnormality occurrence section (divided window section) where an abnormality has occurred in the optical cable unit 400 due to a break in the support wire 400X.

[0057] 7A, 7B, and 7C are diagrams showing an example of processing by the corrected distortion waveform acquiring section 640 and the abnormal portion acquiring section 650. FIG.

[0058] 7A shows the original distortion change amount waveform, i.e., the distortion waveform of the monitored section of the optical cable unit 400 acquired by the distortion waveform acquisition unit 620. This distortion waveform includes (combines) a steep peak due to a break in the support wire 400X of the optical cable unit 400 and gradual fluctuations due to disturbances.

[0059] FIG. 7B shows the post-filtering spectrogram, i.e., the distorted waveform acquired in FIG. 7A, being Fourier transformed, and removing (filtering) the disturbance waveform acquired by the disturbance waveform acquisition section 630 from the distorted waveform after the Fourier transformation.

[0060] 7C shows the distortion change waveform after filtering, i.e., the corrected distortion waveform obtained by performing an inverse Fourier transform on the removed waveform obtained in FIG. 7B. This corrected distortion waveform is obtained by removing (filtering) the disturbance waveform from the distortion waveform, eliminating gradual fluctuations due to disturbances and highlighting the steep peaks caused by breaks in the support wire 400X of the optical cable unit 400. The abnormality location acquisition unit 650 acquires, within the monitored section of the optical cable unit 400, locations where the amplitude (steep peaks) of the corrected distortion waveform is equal to or greater than a threshold, as abnormal locations in the optical cable unit 400 caused by breaks in the support wire 400X. In the example of FIG. 7C, the abnormality location acquisition unit 650 determines that two locations where the amplitude (steep peaks) of the corrected distortion waveform is equal to or greater than a threshold match abnormal locations in the optical cable unit 400 caused by breaks in the support wire 400X.

[0061] 8A and 8B are diagrams showing an example of processing by the abnormal part acquisition unit 650. In order to prevent erroneous detection due to residual noise after the inverse Fourier transform, it is preferable that the abnormal part acquisition unit 650 additionally executes the processing shown in Fig. 8A and 8B.

[0062] 8A shows a different post-filtering distortion waveform, i.e., a corrected distortion waveform that, unlike FIG. 7C, contains residual noise after inverse Fourier transform. If such residual noise is included, there will be places where the amplitude of the corrected distortion waveform exceeds the threshold even though no break has occurred in support line 400X, which will cause a false detection.

[0063] Therefore, in this embodiment, the abnormality location acquisition unit 650 defines a plurality of divided monitoring sections (divided window sections) by dividing the monitored section of the optical cable unit 400, and for each divided monitoring section (each divided window section), calculates a divided abnormality score by adding up the average value and standard deviation of the corrected distortion waveform, and acquires the divided monitoring section (divided window section) among each divided monitoring section (each divided window section) whose divided abnormality score is equal to or greater than the threshold score as the divided abnormality occurrence section (divided window section) where an abnormality has occurred in the optical cable unit 400 due to a break in the support wire 400X.

[0064] In this case, it is preferable that the steps of Fourier transforming the distorted waveform, obtaining a removed waveform by removing the disturbance waveform from the distorted waveform after Fourier transform, and obtaining a corrected distorted waveform by inverse Fourier transforming the removed waveform are performed for each of a plurality of divided monitored sections (divided window sections) obtained by dividing the monitored section of the optical cable unit 400.

[0065] 8B shows the corrected distortion waveform after removing the residual noise after the inverse Fourier transform. In the corrected distortion waveform after removing the residual noise, the points (two points in the illustrated example) where the amplitude of the corrected distortion waveform is equal to or greater than the threshold value accurately (pinpoint) identify the abnormal point in the optical cable unit 400 caused by the breakage of the support wire 400X, thereby reliably preventing the occurrence of false detection.

[0066] 8A and 8B, a divided anomaly score is calculated by multiplying the average value and standard deviation of the corrected distortion waveform for each point (each divided monitoring section, each divided window section), and a point (divided monitoring section, divided window section) where the divided anomaly score is equal to or greater than the threshold score is determined to be an abnormal point (abnormal divided monitoring section, abnormal divided window section). There is a degree of freedom in how the threshold score is set, and various design modifications are possible. For example, the threshold score may be calculated using the average value of the divided anomaly scores for each point (each divided monitoring section, each divided window section), or the threshold score may be calculated using a function that uses the divided anomaly scores for each point (each divided monitoring section, each divided window section) as a variable. Furthermore, the threshold score may be calculated by capturing or weighting points with large signal levels or variations in the divided anomaly scores for each point (each divided monitoring section, each divided window section).

[0067] The calculation process by the abnormality location acquisition unit 650 will be described in more detail with reference to mathematical expressions. The strain data measured for each of the multiple windows in the distance direction (longitudinal direction) is defined as ε(d), the window width of each of the multiple windows in the distance direction (longitudinal direction) is fixed as W, and the start position of each of the multiple windows in the distance direction (longitudinal direction) is defined as di. For each of the multiple windows in the distance direction (longitudinal direction), the average value μ(d) and standard deviation σ(d) of the corrected strain waveform are calculated using the following mathematical expression 1.

number

[0068] The absolute value Δμ(d) of the difference in the average value and the absolute value Δσ(d) of the difference in standard deviation of the corrected distortion waveforms at the distance d and the distance d+W are calculated using the following formula 2. In other words, the difference between the average value and the standard deviation of the corrected distortion waveforms of adjacent windows is calculated using the following formula 2.

number

[0069] The product of the above Δμ(d) and Δσ(d) is defined as the divided anomaly score S(d), and the divided anomaly score S(d) for each of the multiple windows (here, N, which is the number of data points) in the distance direction (longitudinal direction) is calculated using the following formula 3. Then, it is determined whether each of the N divided anomaly scores S(d) is equal to or greater than a threshold score, and the window for which the divided anomaly score S(d) is equal to or greater than the threshold score is acquired as the divided anomaly occurrence section (divided window section) where an abnormality has occurred in the optical cable unit 400 due to a break in the support wire 400X.

number

[0070] 9A and 9B are diagrams showing an example of the amount of change in strain before and after the breakage of the support wire 400X in the cases where there is and is not an external disturbance factor.

[0071] FIG. 9A shows an ideal strain change amount in the absence of any disturbance factors. That is, in a steady state where the support wire 400X is not broken, the strain waveform is a linear waveform in which the vertical axis, which represents the strain change amount of the optical cable unit 400, always maintains a constant value, relative to the horizontal axis, which represents the longitudinal position of the optical cable unit 400 (the distance from the reference position of the optical cable unit 400). In contrast, when the support wire 400X breaks, the strain change amount of the optical cable unit 400 has a local peak only at a portion of the horizontal axis, which represents the longitudinal position of the optical cable unit 400 (the distance from the reference position of the optical cable unit 400), corresponding to the break in the support wire 400X. When the local peak of the strain change amount of the optical cable unit 400 exceeds a fixed threshold, an abnormality in the optical cable unit 400 due to a break in the support wire 400X can be detected. However, an ideal strain change amount without any disturbance factors, such as that shown in FIG. 9A, is practically impossible (cannot be expected).

[0072] 9B shows the actual amount of strain change when there is a disturbance factor. When there is a disturbance factor, even in a steady state where the support wire 400X is not broken, a strain change occurs in the strain waveform according to environmental information such as temperature information, sunshine information, humidity information, wind information, and rain information. Furthermore, when the support wire 400X breaks, the amount of strain change at the portion corresponding to the break in the support wire 400X is added (superimposed) on the strain waveform. As a result, there are multiple locations (three locations in the illustrated example) where the amount of strain change in the optical cable unit 400 exceeds the fixed threshold, making it difficult to identify the abnormal portion of the optical cable unit 400 due to the break in the support wire 400X and may also be a cause of erroneous detection.

[0073] Therefore, this embodiment discloses a monitoring technique for the optical cable unit 400 that removes fluctuations in the distorted waveform due to disturbances, performs highly accurate analysis of the distorted waveform, and suitably detects abnormal locations in the optical cable unit 400 caused by breaks in the support wire 400X. More specifically, the distorted waveform acquisition unit 620, the disturbance waveform acquisition unit 630, and the corrected distorted waveform acquisition unit 640 cooperate to perform a Fourier transform on the distorted waveform, remove the disturbance waveform from the distorted waveform after the Fourier transform, obtain a removed waveform, and then perform an inverse Fourier transform on the removed waveform to obtain a corrected distorted waveform. Then, based on the corrected distorted waveform, the abnormal location acquisition unit 650 acquires abnormal locations in the optical cable unit 400 caused by breaks in the support wire 400X in the monitored section of the optical cable unit 400.

[0074] In addition, disturbance factors (environmental information including temperature information, sunshine information, humidity information, wind information, and rain information) that change from moment to moment and may also vary depending on the longitudinal position of the optical cable unit 400 (the distance from the reference position of the optical cable unit 400) are acquired in a timely manner (in real time), and changes in distortion due to the disturbance factors are predicted by machine learning using regression analysis to acquire a disturbance waveform.The distortion waveform is then Fourier transformed to acquire a removed waveform by removing the disturbance waveform from the distortion waveform after the Fourier transform, and a corrected distortion waveform is acquired by inverse Fourier transforming the removed waveform.Based on the corrected distortion waveform, abnormal locations in the optical cable unit 400 due to breakage of the support wire 400X in the monitored section of the optical cable unit 400 are acquired.

[0075] 10A, 10B, and 10C are diagrams showing the steps of the monitoring method for the optical cable unit 400. FIG.

[0076] 10A, the original distortion change waveform is obtained, that is, the distortion waveform of the monitored section of the optical cable unit 400. This distortion waveform includes (is the sum of) a steep peak due to a break in the support wire 400X of the optical cable unit 400 and a gradual fluctuation due to a disturbance.

[0077] As shown in FIG. 10B, the spectrogram after filtering, that is, the distorted waveform acquired in FIG. 10A is Fourier transformed to acquire a removed waveform by removing the disturbance waveform from the distorted waveform after the Fourier transformation.

[0078] As shown in FIG. 10C, a corrected distortion waveform is obtained by performing an inverse Fourier transform on the distortion change waveform after filtering, i.e., the removed waveform obtained in FIG. 10B. This corrected distortion waveform is obtained by removing the disturbance waveform from the distortion waveform, thereby eliminating gradual fluctuations due to disturbances and highlighting the steep peaks caused by the breakage of the support wire 400X of the optical cable unit 400. Within the monitored section of the optical cable unit 400, a location where the amplitude (steep peak) of the corrected distortion waveform is equal to or greater than a threshold is obtained as an abnormal location in the optical cable unit 400 caused by a breakage of the support wire 400X. In the example of FIG. 10C, one location where the amplitude (steep peak) of the corrected distortion waveform is equal to or greater than the threshold is determined to match the abnormal location in the optical cable unit 400 caused by a breakage of the support wire 400X, enabling accurate and pinpoint detection of the abnormal location in the optical cable unit 400 caused by a breakage of the support wire 400X.

[0079] Second Embodiment In the above first embodiment, the disturbance waveform acquisition unit 630 acquires the disturbance waveform of the monitored section of the optical cable unit 400, the corrected distortion waveform acquisition unit 640 acquires a corrected distortion waveform by correcting the distortion waveform based on the disturbance waveform, and the abnormality location acquisition unit 650 acquires an abnormality location of the optical cable unit 400 caused by a break in the support wire 400X in the monitored section of the optical cable unit 400 based on the corrected distortion waveform.

[0080] On the other hand, for example, if the effect of disturbances in the monitored section of the optical cable unit 400 is small enough to be negligible, it is also possible to omit (disable) the disturbance waveform acquisition unit 630 and the corrected distortion waveform acquisition unit 640. In this case, the abnormality location acquisition unit 650 replaces the corrected distortion waveform with a distortion waveform and, based on the distortion waveform, can acquire an abnormality location of the optical cable unit 400 caused by a break in the support wire 400X in the monitored section of the optical cable unit 400. More specifically, the abnormality location acquisition unit 650 can acquire, within the monitored section of the optical cable unit 400, a location where the amplitude of the distortion waveform is equal to or greater than a threshold, as an abnormality location of the optical cable unit 400 caused by a break in the support wire 400X.

[0081] Furthermore, whether or not to activate the disturbance waveform acquirer 630 and the corrected distortion waveform acquirer 640 may be switched depending on the state of disturbance in the monitored section of the optical cable unit 400. When the disturbance waveform acquirer 630 and the corrected distortion waveform acquirer 640 are activated, the abnormality location acquirer 650 may acquire, based on the corrected distortion waveform, an abnormality location in the optical cable unit 400 caused by a break in the support wire 400X in the monitored section of the optical cable unit 400. When the disturbance waveform acquirer 630 and the corrected distortion waveform acquirer 640 are not activated, the abnormality location acquirer 650 may acquire, based on the distortion waveform, an abnormality location in the optical cable unit 400 caused by a break in the support wire 400X in the monitored section of the optical cable unit 400. In this way, the distortion waveform and the corrected distortion waveform may be interpreted interchangeably, and the distortion waveform may be used as a broad concept including the corrected distortion waveform.

[0082] As described above, the optical cable unit monitoring device of this embodiment is a monitoring device for an optical cable unit in which an optical cable is supported by a support wire, and includes a distortion waveform acquisition unit that acquires a distortion waveform in a monitored section of the optical cable unit, and an abnormality location acquisition unit that acquires, based on the distortion waveform, an abnormality location in the optical cable unit caused by a break in the support wire that supports the optical cable in the monitored section of the optical cable unit. This makes it possible to preferably detect an abnormality location in the optical cable unit caused by a break in the support wire. In other words, by capturing the precursor to a break in the support wire leading to a break in the optical cable, it is possible to preferably detect an abnormality location in the optical cable unit at a stage before a chain reaction of breaks in the optical cable occurs (a stage when the optical cable is functioning normally), and to perform appropriate repairs or treatment.

[0083] Furthermore, according to the optical cable unit monitoring device of this embodiment, optical fiber strain distribution sensing can be used to identify the location where a support wire breakage has occurred in the optical cable unit from the amount of change in the strain distribution characteristics, thereby enabling rapid inspection.

[0084] Furthermore, in the optical cable unit monitoring device of this embodiment, the distorted waveform acquisition unit, disturbance waveform acquisition unit, and corrected distorted waveform acquisition unit work together to perform a Fourier transform on the distorted waveform, remove the disturbance waveform from the distorted waveform after the Fourier transform to obtain a removed waveform, and then perform an inverse Fourier transform on the removed waveform to obtain a corrected distorted waveform.The abnormality location acquisition unit then acquires abnormal locations in the optical cable unit caused by breaks in the support wires in the monitored section of the optical cable unit based on the corrected distorted waveform.This makes it possible to identify abnormal locations in the optical cable unit with high accuracy.At the same time, it is possible to simplify the structure of the device, make it smaller, and reduce costs.

[0085] Furthermore, the optical cable unit monitoring device of this embodiment includes a strain measuring instrument that measures strain occurring at each position along the longitudinal direction of the optical fiber and a strain analysis device that acquires and analyzes the strain measurement data, and the strain analysis device executes the strain analysis method of this embodiment. The strain analysis method of this embodiment analyzes changes in strain occurring at each position along the longitudinal direction of the optical fiber to identify the location of a support wire break, separating strain changes caused by the influence of outside temperature and wind, extracting the strain change due to the support wire break, and identifying the location of the change. Because the strain that changes due to a support wire break has a local peak, it is expected that an abnormality due to a support wire break can be identified by setting an appropriate threshold and detecting the position that deviates from the threshold. However, because the strain of the optical fiber changes overall due to the influence of outside temperature, wind, etc. (external disturbance factors), it is usually difficult to identify only the strain due to the support wire break. Therefore, in this embodiment, by focusing on the fact that the strain change due to a support wire breakage forms a steep peak, while the strain characteristics on the optical fiber due to a disturbance change gradually in the longitudinal direction, the strain change due to this disturbance is separated and the exact location of the support wire breakage is identified. In particular, by using Fourier transform to separate the strain change caused by the influence of the outside temperature and wind, it is possible to extract only the strain change due to the support wire breakage, which can lead to the identification of the fault location.

[0086] The optical cable unit monitoring method (distortion analysis method) of this embodiment is realized by, for example, executing the following processing. (1) Obtain strain data of the aerial optical cable (optical cable unit) using a strain measuring device. (2) Obtain reference strain distribution data before the occurrence of strong winds, etc., and then compare the reference strain distribution data with the strain data obtained in (1) above to calculate the amount of change. (3) A Fourier transform is performed at each interval (divided monitoring section). (4) Low-frequency components containing distortion changes due to disturbances are removed by a filter. (5) An inverse Fourier transform is performed to estimate the location of the fault as being a point that deviates from a predetermined threshold. (6) To prevent false positives due to residual noise after the inverse Fourier transform, the product of the difference between the average and standard deviation of the distortion change amount in an arbitrary window width (section to be monitored) is defined as a change score and calculated longitudinally. A threshold is then calculated from the average value of the distortion change score distribution, and any point that deviates from this threshold is identified as a fault point.

[0087] The optical cable unit monitoring technology of this embodiment enables advanced signal processing to eliminate the effects of disturbances. This embodiment employs a method for separating and eliminating the effects of distortion caused by disturbances (such as outside temperature and wind) using Fourier transform. Normally, it is difficult to completely eliminate the effects of environmental changes when measuring distortion using optical fiber sensing, and simple threshold-based judgments have a high risk of false detection. Therefore, this embodiment establishes a technology that combines Fourier transform and filtering to extract only steep peaks such as support lines. This technology is distinct from conventional technology because it requires not just a combination of mathematical formulas but also parameter design (window size, frequency cutoff value) that effectively operates with the company's communications infrastructure equipment, based on the spatial frequency characteristics of distortion. (Even those skilled in the art would not be able to easily invent this technology.)

[0088] The optical cable unit monitoring technology of this embodiment enables linking to physical phenomena. While technologies such as BOTDR are widely used in the field of optical fiber strain analysis, this embodiment adds signal processing technology to achieve more accurate anomaly detection. However, the characteristics of strain data acquired by BOTDR when a support wire breaks cannot be determined simply by acquiring sensor data. For example, it is impossible to predict what physical phenomenon and characteristics will be obtained when a support wire breaks without understanding the type and structure of the communication cable. Therefore, this embodiment does not simply use a strain sensor; it requires a deep understanding of the mechanical properties of the communication cable, making it a technology that stands out from conventional technology (and is not easily invented even by those skilled in the art).

[0089] The optical cable unit monitoring technology of this embodiment makes it possible to establish an analysis flow for highly accurate anomaly detection. In this embodiment, a series of processes (Fourier transform, filtering, inverse transform, and threshold judgment) from acquisition of measurement data to anomaly detection are systematized. While a typical business operator may be limited to simple anomaly detection based on threshold setting alone, this embodiment achieves improved accuracy by combining data analysis techniques. Putting this technology to a practical level requires the accumulation of experimental data and simulations in an environment with a wide-area optical fiber network, making it a technology that stands out from conventional technology (and one that even a person skilled in the art would not easily invent).

[0090] Although the invention according to the present disclosure has been described in detail above, it is clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described in the present disclosure. The invention according to the present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the description of the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not impose any limiting meaning on the invention according to the present disclosure. [Explanation of symbols]

[0091] 100 FTTH systems 200 devices 300 Receiving Station 400 Optical cable unit (self-supporting cable, aerial optical cable, aerial optical cable unit) 400X support line 400Y optical cable 400Z neck 400-1~400-N Split monitoring section 410 Spacer 420 Slots 430 Optical fiber bundle (tape-shaped optical fiber) 430a optical fiber 440 Tension member 450 Waterproof Tape 460 Outer skin (sheath) 500A 500B 500C Relay section (electric pole) 600 Optical cable unit monitoring device 610 Monitoring target section identification unit 620 Distortion waveform acquisition unit 630 Disturbance waveform acquisition unit 640 Correction distortion waveform acquisition unit 650 Abnormality location acquisition unit

Claims

1. A monitoring device for an optical cable unit in which an optical cable is supported on a support wire, a distortion waveform acquiring unit for acquiring a distortion waveform of a section to be monitored of the optical cable unit; a disturbance waveform acquisition unit that acquires a disturbance waveform of the monitoring target section of the optical cable unit; a corrected distortion waveform acquisition unit that acquires a corrected distortion waveform by correcting the distortion waveform based on the disturbance waveform; an abnormality location acquiring unit that acquires an abnormality location of the optical cable unit due to a break in the support wire in the monitored section of the optical cable unit based on the corrected distortion waveform; 1. A monitoring device for an optical cable unit, comprising:

2. the corrected distortion waveform acquisition unit performs a Fourier transform on the distorted waveform to acquire a removed waveform by removing the disturbance waveform from the distorted waveform after the Fourier transform, and then performs an inverse Fourier transform on the removed waveform to acquire the corrected distortion waveform.

2. The optical cable unit monitoring device according to claim 1.

3. the abnormality location acquisition unit acquires a location in the monitored section of the optical cable unit where the amplitude of the corrected distortion waveform is equal to or greater than a threshold as an abnormality location of the optical cable unit caused by a break in the support wire.

3. The optical cable unit monitoring device according to claim 2.

4. the abnormality location acquisition unit defines a plurality of divided monitoring target sections obtained by dividing the monitoring target section of the optical cable unit, calculates a divided abnormality score for each divided monitoring target section by integrating the average value and standard deviation of the corrected distortion waveform, and acquires, among each divided monitoring target section, a divided monitoring target section whose divided abnormality score is equal to or greater than a threshold score as a divided abnormality occurrence section in which an abnormality has occurred in the optical cable unit due to a break in the support wire.

4. The optical cable unit monitoring device according to claim 3.

5. A monitoring method for an optical cable unit in which an optical cable is supported on a support wire, comprising: acquiring a distortion waveform of a monitored section of the optical cable unit; acquiring a disturbance waveform of the monitored section of the optical cable unit; obtaining a corrected distorted waveform by correcting the distorted waveform based on the disturbance waveform; acquiring an abnormality location of the optical cable unit due to a break in the support wire in the monitored section of the optical cable unit based on the corrected distortion waveform; 1. A method for monitoring an optical cable unit, comprising:

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