JP4156482B2 - Optical fiber cable deterioration detection system - Google Patents

Description

  The present invention relates to an optical fiber cable deterioration detection system.

Conventionally, as a method for detecting the presence or absence of water in an optical fiber cable installed in a pipe network or the like, for example, a water absorbing material that absorbs water and expands or contracts in volume is provided in the optical fiber cable. A method is known in which an optical pulse tester detects an increase in optical transmission loss caused by local bending deformation of an optical fiber due to volume expansion or contraction of the optical fiber (for example, see Patent Document 1).
In addition, for example, a reaction material that generates heat or absorbs heat by reacting with water is provided in an optical fiber cable, and a local temperature change generated in the optical fiber due to heat generation or heat absorption of the reaction material is detected by an optical pulse tester ( For example, see Patent Document 2).
JP-A-62-28703 Japanese Patent Laid-Open No. 6-18754

However, in the inundation detection method according to the related art as described above, the optical fiber is bent or deformed by the water immersion in the optical fiber cable, or the optical fiber is cooled or heated, so that the optical fiber cable is deteriorated. There is a risk that the condition will be promoted.
When the deterioration state of the optical fiber cable is promoted in this way, for example, when it is necessary to perform communication using the optical fiber cable in the period until the maintenance work is performed even after the inundation is detected. There is a risk that the characteristics will be excessively deteriorated, or the labor required for maintenance work performed after the detection of inundation will become complicated.
The present invention has been made in view of the above circumstances, and can appropriately and accurately detect a deterioration state such as the presence or absence of water in the optical fiber cable while preventing the deterioration state of the optical fiber cable from being promoted. It is an object of the present invention to provide a degradation detection system for an optical fiber cable that can be used.

In order to solve the above-described problem, the optical fiber cable deterioration detection system according to claim 1 includes an optical pulse incident on an optical fiber in the optical fiber cable from an incident end, and is included in the return light returned to the incident end. An optical pulse tester that detects the temperature distribution in the longitudinal direction of the optical fiber cable as time-series data using the predetermined scattered light, and the temperature distribution in the longitudinal direction of the optical fiber cable output from the optical pulse tester. Using the detection data consisting of the time series data or the data related to the detection data as processing target data, the processing target data is subjected to a smoothing process on a distance in a predetermined range in the longitudinal direction of the optical fiber cable, thereby smoothing the distance. A distance smoothing means for generating data, and a predetermined range of the time-series data with respect to the processing target data; A time-smoothing means for performing a smoothing process for generating a time-smoothed data, and a temperature change for calculating the time change data of the temperature distribution in the longitudinal direction of the optical fiber cable for the processing target data A determination is made as to whether or not a temperature change due to a supercooling phenomenon has occurred in the data of the time change amount of the temperature distribution in the longitudinal direction of the optical fiber cable calculated by the amount calculation means and the temperature change amount calculation means Deterioration determining means for determining the presence or absence of water immersion in the optical fiber cable, wherein the deterioration determining means is configured to determine whether the temperature of the optical fiber cable is water or not in the time variation data of the temperature distribution. after drops below freezing point, that it is possible to determine the temperature change due to supercooling phenomenon when temporarily predetermined amount raised and lowered Patent To.

  According to the optical fiber cable deterioration detection system having the above configuration, the temperature distribution in the longitudinal direction of the optical fiber cable obtained by detecting predetermined scattered light included in the return light, such as Raman scattered light or Brillouin scattered light, is obtained. The following processing, that is, smoothing processing relating to a predetermined range of distance, smoothing processing relating to a predetermined range of time, and processing for calculating a temporal change amount of the temperature distribution are executed on detection data composed of time series data in an appropriate order. This makes it possible to accurately detect a desired temperature change state (for example, a temperature change due to a supercooling phenomenon) at an appropriate position in the longitudinal direction of the optical fiber cable.

Furthermore, in the optical fiber cable degradation detection system according to the second aspect of the present invention, the distance smoothing means sets the distance in the predetermined range according to information on the distance of the optical fiber cable in the processing target data. It is characterized by that.

  According to the optical fiber cable deterioration detection system having the above-described configuration, the distance within a predetermined range for performing the smoothing process can be appropriately set according to the distance information of the processing target data, and the optical fiber cable in the longitudinal direction of the optical fiber cable. The detection accuracy of a desired temperature change state at an appropriate position can be improved.

  Furthermore, in the optical fiber cable deterioration detection system according to the third aspect of the present invention, the time smoothing means performs the smoothing process a plurality of times on the processing target data.

  According to the optical fiber cable deterioration detection system having the above-described configuration, the detection accuracy of a desired temperature change state at an appropriate position in the longitudinal direction of the optical fiber cable can be improved by performing a plurality of smoothing processes. it can.

Furthermore, in the optical fiber cable deterioration detection system according to the present invention as set forth in claim 4, the time smoothing means sets the number of times the smoothing process is executed according to information on the distance of the optical fiber cable in the processing target data. It is characterized by setting.

  According to the optical fiber cable deterioration detection system having the above-described configuration, a desired number of times in the longitudinal direction of the optical fiber cable can be obtained by performing an appropriate number of smoothing processes according to the distance information of the processing target data. The detection accuracy of the temperature change state can be improved.

  Furthermore, in the optical fiber cable deterioration detection system according to the fifth aspect of the present invention, the smoothing process is an average value calculation process, a moving average value calculation process, a median value calculation process, or a moving median value calculation process. It is a feature.

  According to the optical fiber cable degradation detection system having the above-described configuration, the smoothing process is performed as an average value calculation process, a moving average value calculation process, a median value calculation process, or a moving median value calculation process. The detection accuracy of a desired temperature change state at an appropriate position in can be improved.

  Furthermore, in the optical fiber cable deterioration detection system according to the sixth aspect of the present invention, the temperature change amount calculating means calculates a difference of the processing target data with respect to a predetermined reference temperature.

  According to the optical fiber cable deterioration detection system configured as described above, for a plurality of processing target data, for example, for each processing target data having the same time information, the difference between the processing target data with respect to a predetermined reference temperature is calculated. Thus, it is possible to easily calculate the amount of time change of the temperature distribution in the longitudinal direction of the optical fiber cable.

  Furthermore, in the optical fiber cable deterioration detection system according to the present invention as set forth in claim 7, the temperature change amount calculation means is the processing target that is the calculation target of the difference among the plurality of processing target data forming a time series. The processing target data that is a predetermined time or a predetermined number before the data is set as the predetermined reference temperature.

  According to the optical fiber cable degradation detection system configured as described above, a desired temperature change state at an appropriate position in the longitudinal direction of the optical fiber cable can be detected easily and accurately.

Furthermore, in the optical fiber cable deterioration detection system according to the present invention as set forth in claim 8, the temperature change amount calculating means is configured to determine the predetermined time or the predetermined number according to information on the distance of the optical fiber cable in the processing target data. It is characterized by setting.

  According to the optical fiber cable deterioration detection system configured as described above, the predetermined time or the predetermined number when setting the predetermined reference temperature can be set to an appropriate value according to the distance information of the processing target data. The detection accuracy of a desired temperature change state at an appropriate position in the longitudinal direction of the fiber cable can be improved.

  Furthermore, the degradation detection system for an optical fiber cable of the present invention according to claim 9 is characterized in that, in the data of the temporal variation of the temperature distribution in the longitudinal direction of the optical fiber cable calculated by the temperature variation calculation means, Whether or not water is immersed in the optical fiber cable by determining whether or not a time delay with respect to an appropriate temperature change occurs according to the specific heat in the longitudinal direction of the optical fiber cable or the distribution of the state quantity related to the specific heat It is characterized by comprising a deterioration judging means (34) for judging the above.

  According to the optical fiber cable deterioration detection system having the above-described configuration, it is possible to accurately detect a desired temperature change state (for example, a temperature change due to a supercooling phenomenon) at an appropriate position in the longitudinal direction of the optical fiber cable. In addition, the presence or absence of water in the optical fiber cable can be easily determined by determining whether there is a time delay for an appropriate temperature change according to the specific heat difference between the submerged part and the non-submerged part. Furthermore, this determination accuracy can be improved.

The degradation detection system for an optical fiber cable according to the first aspect of the present invention is the subcooling phenomenon in the time variation data of the temperature distribution in the longitudinal direction of the optical fiber cable calculated by the temperature variation calculation means. It is characterized by comprising deterioration determining means for determining whether or not the optical fiber cable is submerged by determining whether or not a temperature change due to is occurring.

  According to the optical fiber cable degradation detection system configured as described above, by determining whether or not a temperature change due to a supercooling phenomenon has occurred as a predetermined temperature change state generated in the optical fiber cable, the optical fiber cable enters the optical fiber cable. It is possible to easily determine the presence or absence of water immersion and improve the determination accuracy.

  According to the optical fiber cable deterioration detection system of the present invention, the detection data obtained by detecting the predetermined scattered light included in the return light is sequentially related to the smoothing process related to the distance in the predetermined range and the time in the predetermined range. By executing the smoothing process and the process of calculating the time variation of the temperature distribution, the desired temperature change state (for example, temperature change due to the supercooling phenomenon) at an appropriate position in the longitudinal direction of the optical fiber cable can be accurately obtained. It can be detected well.

Furthermore, according to the optical fiber cable deterioration detection system of the second aspect of the present invention, it is possible to appropriately set the distance within a predetermined range for performing the smoothing process in accordance with the distance information of the detection data. The detection accuracy of a desired temperature change state at an appropriate position in the longitudinal direction of the fiber cable can be improved.
Furthermore, according to the optical fiber cable deterioration detection system of the present invention described in claim 3, the desired temperature change state at an appropriate position in the longitudinal direction of the optical fiber cable can be obtained by performing a plurality of smoothing processes. Detection accuracy can be improved.
Furthermore, according to the degradation detection system for an optical fiber cable of the present invention as set forth in claim 4, the longitudinal direction of the optical fiber cable is performed by performing an appropriate number of smoothing processes according to the distance information of the distance smoothing data. The detection accuracy of a desired temperature change state at an appropriate position in can be improved.

Furthermore, according to the optical fiber cable degradation detection system of the present invention described in claim 5, it is possible to improve the detection accuracy of a desired temperature change state at an appropriate position in the longitudinal direction of the optical fiber cable.
Furthermore, according to the optical fiber cable degradation detection system of the present invention described in claim 6, it is possible to easily calculate the amount of time change of the temperature distribution in the longitudinal direction of the optical fiber cable.

Furthermore, according to the optical fiber cable degradation detection system of the present invention described in claim 7, it is possible to easily and accurately detect a desired temperature change state at an appropriate position in the longitudinal direction of the optical fiber cable.
Further, according to the optical fiber cable deterioration detection system of the present invention as set forth in claim 8, the predetermined time or the predetermined number when setting the predetermined reference temperature is an appropriate value corresponding to the distance information of the time smoothing data. Therefore, the detection accuracy of a desired temperature change state at an appropriate position in the longitudinal direction of the optical fiber cable can be improved.

Furthermore, according to the optical fiber cable degradation detection system of the present invention described in claim 9, a desired temperature change state (for example, temperature change due to a supercooling phenomenon) at an appropriate position in the longitudinal direction of the optical fiber cable is obtained. In addition to being able to detect with high accuracy, by determining whether or not a time delay with respect to an appropriate temperature change has occurred according to the specific heat difference between the submerged part and the non-submerged part, The presence or absence of water immersion can be easily determined, and the determination accuracy can be improved.
According to the degradation detection system for an optical fiber cable of the present invention described in claim 1, by determining whether or not a temperature change due to a supercooling phenomenon has occurred as a predetermined temperature change state occurring in the optical fiber cable, The presence / absence of water immersion in the optical fiber cable can be easily determined, and the determination accuracy can be improved.

Hereinafter, an embodiment of a degradation detection system for an optical fiber cable according to the present invention will be described with reference to the accompanying drawings.
The optical fiber cable degradation detection system 10 according to the present embodiment detects, for example, the presence or absence of water in the optical fiber cable 11 as the degradation state of the optical fiber cable 11 to be detected. As shown in FIG. 1, the detection-side terminal device 10a and the control-side terminal device 10b are configured to include an optical switch 12, a first optical pulse tester 13, and a second optical pulse. The tester 14, the third optical pulse tester 15, the control device 16, the input device 17, the output device 18, and the detection side communication device 19 are configured, and the control side terminal device 10 b is, for example, The control side communication device 21, the control device 22, the input device 23, and the output device 24 are provided.

  The detection-side terminal device 10a and the control-side terminal device 10b can be connected to each other via the detection-side communication device 19 and the control-side communication device 21, and the control-side terminal device 10b can detect the detection-side terminal device 10a. The operation, for example, the switching connection operation of the optical switch 12 to be described later, the detection operation of each of the optical pulse testers 13, 14, 15 and the like can be controlled. It is possible to output to the output device 24 included in 10b.

The optical fiber cable 11 to be detected is a multi-core optical fiber cable composed of a plurality of optical fibers, for example, and is connected to the optical switch 12.
The optical fiber cable 11 according to the present embodiment is, for example, an OPGW (composite fiber OPtical overhead ground wire) in which an optical fiber is accommodated in an overhead ground wire, and this OPGW is a plurality of (for example, 18 cores) light. An OP unit (OPtical cable unit) in which the fiber is housed in a metal tube is twisted around a metal element wire such as an aluminum-clad steel wire. The lightning protection function of the overhead power transmission line and optical fiber communication / information It is a transmission line with integrated management functions.

  The optical switch 12 selectively selects each of the optical fibers for detection 13a, 14a, 15a of each optical pulse tester 13, 14, 15 described later with respect to a plurality of optical fibers of the optical fiber cable 11 under the control of the control device 16. Connect to.

The first optical pulse tester 13 of the detection-side terminal device 10a detects the intensity distribution of the Raman scattered light in the longitudinal direction of the optical fiber, for example, by measuring the intensity of the Raman scattered light included in the return light on the time axis. ROTDR (Raman Optical Time Domain Reflectometry) device, which consists of two components constituting Raman scattered light, that is, Stokes component shifted to lower frequency side than incident light and shifted to higher frequency side than incident light Based on the fact that the relative relationship of each intensity with the anti-Stokes component (for example, the intensity ratio) depends on the temperature of the optical fiber, the position information in the longitudinal direction of the optical fiber is further detected from the return time of the return light, The temperature distribution in the longitudinal direction of the optical fiber is detected.
The first optical pulse tester 13 controls the optical fiber cable 11 connected to the detection optical fiber 13a via the detection optical fiber 13a, for example, at every predetermined time interval under the control of the control device 16. The test light is incident on the optical fiber, and the return light with respect to the incident light, that is, the light returning to the incident end of the detection optical fiber 13a is observed.

The second optical pulse tester 14 of the detection-side terminal device 10a detects the intensity distribution of the Brillouin scattered light in the longitudinal direction of the optical fiber, for example, by measuring the intensity of the Brillouin scattered light included in the return light on the time axis. The BOTDR (Brillouin Optical Time Domain Reflectometry) device is used, and the frequency shift amount of the Brillouin scattered light with respect to the incident light depends on the elongation strain amount of the optical fiber. Position information in the longitudinal direction of the fiber is detected, and the presence or absence of elongation strain deformation in the longitudinal direction of the optical fiber is detected.
The second optical pulse tester 14 controls the optical fiber cable 11 connected to the detection optical fiber 14a via the detection optical fiber 14a, for example, at predetermined time intervals under the control of the control device 16. Test light is incident on the optical fiber, and return light with respect to this incident light, that is, light returning to the incident end of the detection optical fiber 14a is observed.

  The third optical pulse tester 15 of the detection-side terminal device 10a determines the intensity distribution of, for example, Rayleigh scattered light included in the return light, or reflected light (for example, Fresnel reflected light) from, for example, a broken position of the optical fiber. It constitutes an OTDR (Optical Time Domain Reflectometry) device for detection.

The control device 16 controls the switching connection operation of the optical switch 12 and the detection operation of each of the optical pulse testers 13, 14, 15, and detects the detection data obtained by each of the optical pulse testers 13, 14, 15. Perform data processing. For example, the control device 16 acquires the detection result of the temperature distribution according to the distance in the longitudinal direction of the optical fiber output from the first optical pulse tester 13 as time series data, and performs data processing of the acquired detection data. The distance direction data processing unit 31, the time direction data processing unit 32, the temperature change amount calculation unit 33, and the inundation determination unit 34 are configured.
Here, the detection data A (n, m) output from the first optical pulse tester 13 is set at a predetermined distance (sampling distance) in the longitudinal direction of the optical fiber, for example, as shown in Table 1 below. that each point L ₁ of the _distance, ..., and L n _(n is an arbitrary natural number), the first predetermined period of time-series data output from the optical pulse tester 13 (sampling time) time set for each Points T ₁ ,..., T _m (m is an arbitrary natural number).

The distance direction data processing unit 31 applies a predetermined distance related to the detection data A (n, m) output from the first optical pulse tester 13 for each time point T ₁ ,..., T _m , for example. Data processing, for example, average processing, moving average processing, median value acquisition processing, moving median value acquisition processing, and the like are executed.
For example, in the average process, the distance direction data processing unit 31 detects the detection data A (within a predetermined distance range L _{jn to} L _kn (where start point L ₁ ≦ lower limit point L _jn , upper limit point L _kn ≦ end point L _n )). jn, m), ..., and calculates the average value of a (kn, m), sets the calculated average value as data of a predetermined distance range _L jn _{~L kn} center position _{L a.}
Note that when the number of points of the distance to be included within the predetermined distance range L _jn ~L _kn is odd, the distance direction data processing unit 31, a distance point of the corresponding calculated average value at the center position L _a Set as data. On the other hand, if the number of points of the distance to be within a predetermined distance range L _jn ~L _kn is even, the distance direction data processing unit 31, the calculated average value of the two distances sandwiching the center position L _a Of the points, the data is set as the data with the longer or shorter distance.

For example, in the moving average process, the distance direction data processing unit 31 is, for example, in a predetermined distance range L _{jn to} L _kn (where L ₁ ≦ L _jn , L _kn ≦ L _n ), the lower limit point L _jn = start point By sequentially increasing the lower limit point L _jn one point at a time from the state of L ₁ to the state of the upper limit point L _kn = the end point L _n , the so-called predetermined distance range L _{jn to} L _kn after each movement above, detection data a within a predetermined distance range _{L jn ~L kn (jn, m} ), ..., a (kn, m) calculates the average value of the calculated predetermined distance range a mean value L It is set as data in _jn ~L _kn center position _{L a.}

For example, in the median value acquisition process, the distance direction data processing unit 31 detects, for example, the detection data A (jn, Ln) in a predetermined distance range L _{jn to} L _kn (where L ₁ ≦ L _jn , L _kn ≦ L _n ). m), ..., a (kn , calculates the median of m), sets the calculated median as data in a predetermined distance range _L jn _{~L kn} center position _{L a.}
Further, for example, in the moving median value acquisition process, the distance direction data processing unit 31 has, for example, a lower limit point L _jn = in a predetermined distance range L _{jn to} L _kn (where L ₁ ≦ L _jn , L _kn ≦ L _n ). from condition to be starting points _{L 1} down to a state where the upper limit point _{L kn} = end point _{L n,} successively, to increase the lower limit point _{L jn} point by point, so to speak predetermined distance range _L jn _{~L kn} Each time it is moved on the distance axis, the median of the detection data A (jn, m),..., A (kn, m) within the predetermined distance range L _{jn to} L _kn is calculated, and the calculated median is used as the predetermined distance. It is set as data in the range _L jn _{~L kn} center position _{L a.}

For example, the distance direction data processing unit 31 sets the sampling distance to 2 m, sets the number of distance points included in the predetermined distance range L _{jn to} L _kn to 10 points (corresponding to a distance of 20 m), and When the moving average process or the moving median value acquisition process is executed on the detection data (n, m) shown in Table 1, for example, as shown in Table 2 below, distance processing data B (5 ≦ a ≦ n−5, m ) Is output.

Time direction data processing unit 32, to the distance processing data B output from the distance direction the data processing unit 31 (a, m), for example, for each point L _a distance, predetermined data processing with respect to time, for example, An average process, a moving average process, a median value acquisition process, a moving median value acquisition process, and the like are executed.
For example, in the average processing, the time direction data processing unit 32 performs distance processing data B within a predetermined time range T _{jm to} T _km (where start point T ₁ ≦ lower limit point T _jm , upper limit point T _km ≦ end point T _m ). (a, jm), ..., the average value of B (a, km), sets the calculated average value as the data in the central time _{T b} of a predetermined time range _T jm _{through T miles.}
When the number of time points included in the predetermined time range T _{jm to} T _km is an odd number, the time direction data processing unit 32 uses the calculated average value of the time points corresponding to the central time T _b . Set as data. On the other hand, when the number of time points included in the predetermined time range T _{jm to} T _km is an even number, the time direction data processing unit 32 uses the calculated average value of the two times sandwiching the central time T _b . Of the points, the data is set as the data of the earlier or later point.

For example, in the moving average process, the time direction data processing unit 32, for example, in the predetermined time range T _{jm to} T _km (where T ₁ ≦ T _jm , T _km ≦ T _m ), the lower limit point T _jm = the starting point. By sequentially increasing the lower limit point T _jm one point at a time from the state in which T ₁ is reached to the state in which the upper limit point T _km is equal to the end point T _m , the predetermined time range T _{jm to} T _km is expressed as a time axis. Each time it is moved above, the average value of the distance processing data B (a, jm),..., B (a, km) within the predetermined time range T _{jm to} T _km is calculated, and the calculated average value is calculated for the predetermined time range. It is set as the data in the T _jm ~T _km of the center time _{T b.}

For example, the time direction data processing unit 32 sets the sampling time to 30 seconds and sets the number of time points included in the predetermined time range T _{jm to} T _km to 10 points (corresponding to a time of 5 minutes). When the moving average process is performed on the distance processing data B (5 ≦ a ≦ n−5, m) shown in Table 2 above, the time processing data C (5 ≦ a ≦ n) as shown in Table 3 below, for example. -5, 5≤b≤m-5).

The temperature change amount calculation unit 33 executes, for example, an initial time data reference process, a data reference process before a predetermined point, and the like for the time processing data C (a, b) output from the time direction data processing unit 32. Then, a time change amount of the temperature based on a predetermined reference temperature is calculated.
For example, in the initial time data reference processing, the temperature change amount calculation unit 33 uses the time processing data C (a, b) (for example, the earliest time processing data C (a, b) at the point T _b of a predetermined time). ) Is set as a reference temperature, and a difference from the reference temperature is calculated for each time processing data C (a, b).
In addition, in the data reference process before a predetermined point, the temperature change amount calculation unit 33 performs time processing data C (a, b) (for example, one or two points before the point T _b at the previous time by a predetermined number of points). time processing data C (a, b) at time point T _b) were set to the reference temperature, and calculates the difference with respect to the reference temperature each time processing data C (a, b) for each.

For example, the temperature change amount calculation unit 33 performs initial time data reference processing using the earliest time processing data C (a, b) as a reference temperature for the time processing data C (a, b) shown in Table 3 above. or time processing data C (a, b) at point T _b of one point earlier time by performing the predetermined point before data reference process for a reference temperature, for example, as shown in table 4, the temperature processing data D ( 5 ≦ a ≦ n−5, 6 ≦ b ≦ m−5) is output.

The inundation determination unit 34 determines whether or not a predetermined temperature change state has occurred based on the temperature processing data output from the temperature change amount calculation unit 33, and enters the optical fiber cable 11 according to the determination result. Detects the occurrence of flooding.
For example, after inundation into the optical fiber cable 11, since the specific heat is larger in the submerged part than in the non-submerged part where no submergence occurs, appropriate temperature changes occur in the submerged part and the non-submerged part. In this case, a time delay occurs in the time change of the temperature in the submerged part, compared to the time change of the temperature in the non-submerged part.
Thereby, the inundation determination unit 34 determines whether or not a time delay of the temperature change occurs in the time change of the temperature processing data output from the temperature change amount calculation unit 33, and detects the time delay of the temperature change. If so, it is determined that water has entered the optical fiber cable 11.

Furthermore, for example, if the temperature of the optical fiber cable 11 drops below the freezing point due to a decrease in air temperature after the water has entered the optical fiber cable 11, a supercooling phenomenon occurs. The supercooling phenomenon is a phenomenon in which solidification or condensation does not occur even when the liquid or gas is cooled, even if the temperature falls below the temperature at which the phase transition should occur. There is a phenomenon in which the temperature temporarily rises to near the freezing point at the beginning of water freezing and the temperature drops again in about 20 to 30 minutes.
Thereby, the inundation determination unit 34 determines whether or not a temperature change due to the supercooling phenomenon occurs in the time change of the temperature processing data output from the temperature change amount calculation unit 33, and the temperature change due to the supercooling phenomenon. When the occurrence of water is detected, it is determined that water has entered the optical fiber cable 11.

The optical fiber cable deterioration detection system 10 according to the present embodiment has the above-described configuration. Next, the operation of the optical fiber cable deterioration detection system 10, particularly the detection output from the first optical pulse tester 13. Processing for performing data processing of data will be described.
First, in step S01 shown in FIG. 2, the detection result of the temperature distribution according to the distance in the longitudinal direction of the optical fiber output from the first optical pulse tester 13 is acquired as time series data.
Next, in step S02, as will be described later, for the detection data output from the first optical pulse tester 13, as predetermined data processing relating to distance, for example, average processing, moving average processing, median One of the data processing is selected from the acquisition processing and the moving median value acquisition processing.

Next, in step S03, a predetermined distance range (for example, 10 m, 20 m, 40 m, etc.) for performing data processing relating to the distance is set as the data processing range _{RL in the} distance direction.
In step S04, the selected data processing is executed in the set data processing range _RL , and distance processing data is output from the detection data.

  Next, in step S05, as will be described later, for the distance processing data output from the distance direction data processing unit 31, as predetermined data processing relating to time, for example, among average processing, moving average processing, etc. Select any data processing.

Next, in step S06, a predetermined time range (for example, 5 minutes, 10 minutes, etc.) in which data processing relating to time is performed is set as the data processing range _{RT in the} time direction.
In step S07, the selected data processing is executed in the set data processing range _RT , and time processing data is output from the distance processing data.

  Next, in step S08, as will be described later, for example, an initial time data reference process or a predetermined process is performed as a process for calculating a time change amount of the temperature for the time process data output from the time direction data processing unit 32. One of the data processing is selected from the pre-point data reference processing.

Next, in step S09, a reference temperature is set.
In step S10, the selected data processing is executed based on the set reference temperature, and a difference with respect to the reference temperature is calculated for each time processing data.
In step S11, the calculation result in step S10 is output to, for example, the output device 18 of the detection-side terminal device 10a or the output device 24 of the control-side terminal device 10b.

In step S12, it is determined whether or not a predetermined temperature change state, for example, a temperature change due to a supercooling phenomenon, has occurred based on the temperature processing data that is the calculation result in step S10. Accordingly, the presence or absence of water intrusion into the optical fiber cable 11 is detected.
In step S13, the determination result in step S10 is output to, for example, the output device 18 of the detection-side terminal device 10a or the output device 24 of the control-side terminal device 10b, and the series of processing ends.

Below, the process which selects the data process regarding distance in step S02 mentioned above is demonstrated.
First, in step S21 shown in FIG. 3, it is determined whether or not to select an average process.
When the determination result is “YES”, the process proceeds to step S22, the averaging process is set as the data processing method regarding the distance, and the series of processes is ended.
On the other hand, if this determination is “NO”, the flow proceeds to step S23.

In step S23, it is determined whether or not to select moving average processing.
If this determination is “YES”, the flow proceeds to step S 24, the moving average process is set as the data processing method for the distance, and the series of processes is ended.
On the other hand, if this determination is “NO”, the flow proceeds to step S25.

In step S25, it is determined whether or not the median value acquisition process is selected.
If this determination is “YES”, the flow proceeds to step S 26, the median value acquisition process is set as the data processing method for the distance, and the series of processes is ended.
On the other hand, if this determination is “NO”, the flow proceeds to step S 27, the moving median value acquisition process is set as the data processing method for the distance, and the series of processes is ended.

Below, the process which selects the data process regarding time in step S05 mentioned above is demonstrated.
First, in step S31 shown in FIG. 4, it is determined whether or not the averaging process is selected.
If this determination is “YES”, the flow proceeds to step S 32, the averaging process is set as the data processing method related to time, and the series of processes is terminated.
On the other hand, if this determination is “NO”, the flow proceeds to step S33.

In step S33, it is determined whether or not to select moving average processing.
If this determination is “YES”, the flow proceeds to step S 34, the moving average process is set as the data processing method related to time, and the series of processes is terminated.
On the other hand, if this determination is “NO”, the flow proceeds to step S35.

In step S35, it is determined whether or not the median value acquisition process is selected.
If this determination is “YES”, the flow proceeds to step S 36, the median value acquisition process is set as the data processing method related to time, and the series of processes ends.
On the other hand, if this determination is “NO”, the flow proceeds to step S 37, the moving median value acquisition process is set as the time-related data processing method, and the series of processes is terminated.

Below, the process which selects the process which calculates the time variation | change_quantity of temperature in step S08 mentioned above is demonstrated.
First, in step S41 shown in FIG. 5, it is determined whether or not to select an initial time data reference process.
If this determination is “YES”, the flow proceeds to step S 42, an initial time data reference process is set as a process method for calculating the time variation in temperature, and the series of processes is terminated.
On the other hand, if this determination is “NO”, the flow proceeds to step S 43, the data reference process before a predetermined point is set as a processing method for calculating the time variation in temperature, and the series of processes is ended.

Below, the Example which detected the presence or absence of the water immersion in the optical fiber cable 11 using the degradation detection system 10 of the optical fiber cable by this Embodiment mentioned above is described.
In the following first to eleventh embodiments, for example, the detection-side terminal device 10a of the optical fiber cable degradation detection system 10 is arranged indoors, and the optical fiber cable 11 is installed as an OPGW (composite fiber). OPtical overhead Ground Wire) was the detection target. Here, as shown in FIG. 6, for example, the OPGW wired outdoors is configured by fusion-connecting a submerged portion 11 a in which the optical fiber is submerged and a non-submerged portion 11 b in which the optical fiber is not submerged. Has been.

A plurality of thermocouples that detect the surface temperature of the optical fiber cable 11 or the ambient temperature in the vicinity of the optical fiber cable 11 are provided at predetermined positions of the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11, for example, four each. Two temperature sensors 41, ..., 41 are arranged. In addition, an internal temperature sensor 42 for detecting an indoor atmospheric temperature is disposed in the room that houses the detection-side terminal device 10a of the optical fiber cable degradation detection system 10. On the other hand, an outdoor temperature sensor 43 that detects the outdoor atmosphere temperature, a solar radiation sensor 44 that detects the amount of solar radiation outdoors, and a wind speed / wind direction sensor 45 that detects the wind speed and wind direction outdoors are arranged outdoors.
And the data processing regarding distance, the data processing regarding time, and the process which calculates the time variation | change_quantity of temperature are performed sequentially with respect to the detection data output from the 1st optical pulse tester 13, and temperature processing data Was calculated.

First, in the first embodiment, in the data processing related to the distance, the sampling distance is set to 2 m, the number of distance points included in the data processing range _RL is set to 10 points (corresponding to a distance of 20 m), and detection is performed. A moving median value acquisition process was executed on the data to generate distance processing data.
In the time-related data processing, the sampling time is set to 30 seconds, the number of time points included in the data processing range _RT is set to 10 points (corresponding to a time of 5 minutes), and first, distance processing is performed. A first moving average process was performed on the data to generate first time processed data. Next, with respect to the first time processing data, the sampling time and the number of points of time included in the data processing range _RT are set to the same value as the first moving average processing, and the second moving average Processing was performed to generate second time processed data.
Then, in the process of calculating the time change amount of the temperature, the initial time data reference process using the temperature of the first time among the second time process data as the reference temperature was executed to generate the temperature process data.
FIGS. 7A to 7E and FIGS. 8A to 8E show the detection results of the sensors 41, 42, 43, 44, and 45 together with the temperature processing data generated from the ROTDR measurement results. .

Here, FIG. 7A and FIG. 8A show changes in the temperature processing data generated from the ROTDR measurement results in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 according to the time and distance. It is a graph which color-codes and shows for every several different temperature change amount area | region divided | segmented by predetermined temperature change width (for example, 0.2 degreeC).
7 (b) and 8 (b) are graphs obtained by extracting the time change of the temperature processing data for each point of a predetermined distance from the graphs shown in FIG. 7 (a) and FIG. 8 (a). FIG. 7 (b) and 8 (b), points at predetermined distances in the flooded part 11a and the non-flooded part 11b of the optical fiber cable 11 (for example, the 940m point, the 1000m point, the 1020m point, and the 1100m point in the flooded part 11a). And 1120 m point and 1180 m point, and 780 m point, 840 m point, 880 m point, 1260 m point, 1280 m point, and 1340 m point) in the non-flooded portion 11b).
Furthermore, in FIG. 7C and FIG. 8C, the optical fiber cable 11 by the temperature sensors 41,..., 41 disposed at predetermined points in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 is shown. The time change of the detection result of the surface temperature of was shown. Further, FIG. 7D and FIG. 8D show the vicinity of the optical fiber cable 11 by the temperature sensors 41 and 41 arranged at predetermined points in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11. The time change of the detection result of atmospheric temperature was shown.
7 (e) and 8 (e) show temporal changes in the detection results of the solar radiation sensor 44 and the wind speed / wind direction sensor 45. FIG.
In FIGS. 7 (a) to (e) and FIGS. 8 (a) to (e), since the time is set at night, the solar radiation is as shown in FIGS. 7 (e) and 8 (e). The amount is zero. Further, since the wind speed measurement data is acquired as an integer value, for example, for wind speeds weaker than 1 m / s, the measurement data is 0 m / s. That is, in FIG.7 (e) and FIG.8 (e), although the wind speed is displayed as 0 m / s, the wind of the wind speed weaker than 1 m / s is blowing actually, not a windless state It is.

  From these detection results, for example, as shown in FIGS. 7C and 8C, when the submerged portion 11a of the optical fiber cable 11 observed in the detection results of the temperature sensors 41,. Overcooling phenomenon, that is, a phenomenon in which water does not freeze even when the temperature drops below the freezing point, and the temperature temporarily rises to near the freezing point at the beginning of freezing, and the temperature drops again in about 20 to 30 minutes However, for example, as shown in FIGS. 7A and 7B and FIGS. 8A and 8B, the temperature processing data generated from the ROTDR measurement result is similarly observed in the change according to the time and distance. In particular, in FIGS. 7 (a) and 8 (a), it is observed as an island-like region α indicating an island-like distribution state isolated from a macroscopic distribution state with respect to the temperature change amount region in the surroundings. Ruko It is seen.

Next, in the second embodiment, for the detection data near the time when the supercooling phenomenon occurs at the position where the distance of the optical fiber cable 11 is about 8 km, the sampling distance is set to 2 m in the data processing regarding the distance, The number of distance points included in the data processing range _RL was set to 10 points (corresponding to a distance of 20 m), the moving median value acquisition process was executed on the detected data, and the distance processing data was generated.
Then, the data processing related to time, to set the sampling time to 30 seconds, the number of points of time in the data processing range R _T is set to 10 points (corresponding to 5 minutes of time), the distance processing data A moving average process was performed on the data to generate time-processed data.
Then, in the process of calculating the time change amount of the temperature, the initial time data reference process using the temperature of the first time among the time process data as the reference temperature was executed to generate the temperature process data.
9A to 9E show the detection results obtained by the sensors 41, 42, 43, 44, and 45 together with the temperature processing data generated from the ROTDR measurement results.

Further, set in the data processing related to time in the second embodiment, to set the sampling time to 30 seconds, the number of points of time in the data processing range R _T to 10 points (corresponding to 5 minutes of time) First, the first moving average process is performed on the distance processing data, the first time processing data is generated, and then the sampling time and the data processing range are calculated for the first time processing data. The case where the number of time points included in _RT is set to a value equivalent to the first moving average process, the second moving average process is executed, and the second time processed data is generated is the third implementation. As an example.
FIGS. 10A to 10E show the detection results obtained by the sensors 41, 42, 43, 44, and 45 together with the temperature processing data generated from the ROTDR measurement results.

Furthermore, in the process of calculating the amount of time change of temperature in the third embodiment, for the second time process data, for example, about 2 points (corresponding to a time of 1 minute) before the temperature change state. The case where the temperature processing data is generated by executing the data reference processing before a predetermined point using the second time processing data at the time point as the reference temperature is defined as the fourth embodiment.
FIGS. 11A to 11E show the detection results of the sensors 41, 42, 43, 44, and 45, together with the temperature processing data generated from the ROTDR measurement results.

Here, FIG. 9A to FIG. 11A show changes in the temperature processing data generated from the ROTDR measurement results in the submerged portion 11a and the non-submerged portion 11b of the optical fiber cable 11 according to the time and distance. For each of a plurality of different temperature change regions divided by a predetermined temperature change width (for example, 0.2 ° C. for FIGS. 9A and 10A and 0.08 ° C. for FIG. 11A). FIG.
FIGS. 9B to 11B are graphs obtained by extracting and displaying the time change of the temperature processing data for each point of a predetermined distance from the graphs shown in FIGS. 9A to 11A. FIG. 9 (b) to 11 (b), points at predetermined distances in the flooded portion 11a and the non-flooded portion 11b of the optical fiber cable 11 (for example, the 8600m point, the 8660m point, and the 8680m point in the flooded portion 11a, and The time change of the temperature process data in the 8450m point in the non-immersed part 11b, the 8510m point, and the 8530m point) was shown.
Furthermore, in FIG. 9C to FIG. 11C, the optical fiber cable 11 by the temperature sensors 41,..., 41 arranged at predetermined points in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 is shown. The time change of the detection result of the surface temperature of was shown. Further, in FIGS. 9D to 11D, the vicinity of the optical fiber cable 11 by the temperature sensors 41 and 41 arranged at predetermined points in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 are shown. The time change of the detection result of atmospheric temperature was shown.
9 (e) to 11 (e) show temporal changes in the detection results of the solar radiation sensor 44 and the wind speed / wind direction sensor 45. FIG.
9 (a) to (e), FIGS. 10 (a) to (e), and FIGS. 11 (a) to (e), since the time is set at night, FIG. 9 (e) and FIG. As shown in FIGS. 10 (e) and 11 (e), the amount of solar radiation is zero. Further, since the wind speed measurement data is acquired as an integer value, for example, for wind speeds weaker than 1 m / s, the measurement data is 0 m / s. That is, in FIGS. 9 (e), 10 (e), and 11 (e), the wind speed is displayed as 0 m / s. However, in reality, the wind speed is lower than 1 m / s, not in the no wind state. The wind is blowing.

From these detection results, first, as shown in FIGS. 9 (a) and 9 (b) and FIGS. 10 (a) and 10 (b), for example, the second embodiment in which the number of times data processing is executed is one. Compared with, the third embodiment, in which the number of times of data processing related to time is executed, can extract the state of relatively rapid temperature change such as a supercooling phenomenon more clearly. I understand. In particular, in FIG. 9A and FIG. 10A, an island-shaped region α that shows an island-shaped distribution state that is isolated from a macroscopic distribution state with respect to the surrounding temperature change amount region is shown in FIG. Compared to FIG. 9A, in FIG. 9A, the macroscopic distribution state with respect to the temperature change region around the island-shaped region α is smoothed, so that the island-shaped region α is relatively emphasized. Can be observed.
Further, for example, as shown in FIGS. 10 (a) and 10 (b) and FIGS. 11 (a) and 11 (b), in the process of calculating the time variation of the temperature, the first of the second time processing data. Compared to the third embodiment in which the temperature of the time is the reference temperature, for example, the second time processing data at the point of time about 2 points (corresponding to a time of 1 minute) depending on the state of temperature change. It can be seen that the fourth embodiment using the reference temperature can more clearly extract the relatively rapid temperature change state such as the supercooling phenomenon. In particular, in FIGS. 10 (a) and 11 (a), an island-shaped region α showing an island-shaped distribution state isolated from a macroscopic distribution state with respect to the surrounding temperature change amount region is shown in FIG. In a), by calculating the amount of temperature change in a short time on the basis of the temperature two points before, it is possible to extract only a portion where a rapid temperature change has occurred in a short time. Therefore, it can be seen that the island-like region α is emphasized and observed as compared with FIG.

Next, in the fifth embodiment, for the detection data near the time when the supercooling phenomenon occurs at the position where the distance of the optical fiber cable 11 is about 15 km, the sampling distance is set to 2 m in the data processing regarding the distance, The number of distance points included in the data processing range _RL was set to 10 points (corresponding to a distance of 20 m), the moving median value acquisition process was executed on the detected data, and the distance processing data was generated.
In the time-related data processing, the sampling time is set to 30 seconds, the number of time points included in the data processing range _RT is set to 10 points (corresponding to a time of 5 minutes), and first, distance processing is performed. A first moving average process was performed on the data to generate first time processed data. Next, with respect to the first time processing data, the sampling time and the number of points of time included in the data processing range _RT are set to the same value as the first moving average processing, and the second moving average Processing was performed to generate second time processed data.
Then, in the process of calculating the time change amount of the temperature, the initial time data reference process using the temperature of the first time among the second time process data as the reference temperature was executed to generate the temperature process data.
FIGS. 12A to 12E show the detection results of the sensors 41, 42, 43, 44, and 45, together with the temperature processing data generated from the ROTDR measurement results.

Further, in the data processing relating to the distance in the fifth embodiment, the number of distance points included in the data processing range _RL is set to 30 points (corresponding to a distance of 60 m), and the moving median value for the detected data is set. The case where the acquisition processing is executed and the distance processing data is generated is defined as the sixth embodiment.
FIGS. 13A to 13E show the detection results of the sensors 41, 42, 43, 44, and 45 together with the temperature processing data generated from the ROTDR measurement results.

Furthermore, in the process of calculating the amount of time change of temperature in the sixth embodiment, for example, about 2 points (corresponding to a time of 1 minute) before the second time process data, for example, depending on the state of temperature change. The case where the temperature processing data is generated by executing the data reference processing before a predetermined point using the second time processing data at the time point as the reference temperature is defined as the seventh embodiment.
14A to 14E show the detection results obtained by the sensors 41, 42, 43, 44, and 45 together with the temperature processing data generated from the ROTDR measurement results.

Here, FIGS. 12A to 14A show changes in temperature treatment data generated from the ROTDR measurement results in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 according to time and distance. For each of a plurality of different temperature change areas divided by a predetermined temperature change width (for example, 0.2 ° C. for FIGS. 12A and 13A and 0.08 ° C. for FIG. 14A). FIG.
Moreover, FIG.12 (b)-FIG.14 (b) are the graphs which extracted and displayed the time change of the temperature processing data for every point of predetermined distance from the graph shown to Fig.12 (a)-FIG.14 (a). FIG. 12 (b) to 14 (b), points at predetermined distances in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 (for example, the 14970m point, the 15030m point and the 15050m point in the submerged part 11a, and The time change of the temperature processing data at the 14810m point, the 14870m point, and the 14890m point) in the non-immersed part 11b was shown.
Furthermore, in FIG. 12C to FIG. 14C, the optical fiber cable 11 by the temperature sensors 41,..., 41 arranged at a predetermined distance in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11. The time change of the detection result of the surface temperature of was shown. Further, in FIGS. 12D to 14D, the vicinity of the optical fiber cable 11 by the temperature sensors 41 and 41 arranged at predetermined points in the submerged part 11a and the non-submerged part 11b of the optical fiber cable 11 are shown. The time change of the detection result of atmospheric temperature was shown.
In addition, FIGS. 12E to 14E show temporal changes in the detection results of the solar radiation sensor 44 and the wind speed / wind direction sensor 45.
In FIGS. 12A to 12E, 13A to 13E, and 14A to 14E, the time is set at night. As shown in FIGS. 13 (e) and 14 (e), the amount of solar radiation is zero. Further, since the wind speed measurement data is acquired as an integer value, for example, for wind speeds weaker than 1 m / s, the measurement data is 0 m / s. That is, in FIGS. 12 (e), 13 (e), and 14 (e), the wind speed is displayed as 0 m / s. However, in actuality, the wind speed is lower than 1 m / s, not in the no wind state. The wind is blowing.

From these detection results, first, as shown in FIGS. 12A and 12B, for example, in the data processing related to distance, the number of distance points included in the data processing range _RL is 10 points. Then, it becomes difficult to clearly extract a state of a relatively rapid temperature change such as a supercooling phenomenon. This is due to an increase in measurement error due to the relatively long ROTDR measurement distance. For this reason, as shown in FIGS. 13A and 13B, the sixth embodiment in which the number of points of the distance is increased to 30 points and the effect of the smoothing process is improved is less in the subcooling phenomenon or the like. It can be seen that the relatively sudden temperature change state can be extracted more clearly. In particular, in FIG. 12A and FIG. 13A, an island-shaped region α showing an island-shaped distribution state that is isolated from a macroscopic distribution state with respect to the surrounding temperature change amount region is shown in FIG. Compared to FIG. 12A, in FIG. 12A, the macroscopic distribution state with respect to the temperature change amount region around the island-shaped region α is smoothed, so that the island-shaped region α is relatively emphasized. Can be observed.
Further, for example, as shown in FIGS. 13 (a) and 13 (b) and FIGS. 14 (a) and 14 (b), in the process of calculating the time change amount of the temperature, the first of the second time processing data. Compared to the sixth embodiment in which the temperature of the time is the reference temperature, for example, the second time processing data at the time point of about 2 points (corresponding to a time of 1 minute) depending on the state of temperature change. It can be seen that the seventh embodiment using the reference temperature can more clearly extract the relatively sudden temperature change state such as the supercooling phenomenon. In particular, in FIGS. 13 (a) and 14 (a), an island-like region α showing an island-like distribution state isolated from a macroscopic distribution state with respect to the temperature change amount region in the surroundings is shown in FIG. In a), by calculating the amount of temperature change in a short time on the basis of the temperature two points before, it is possible to extract only a portion where a rapid temperature change has occurred in a short time. Therefore, it can be seen that the island-like region α is emphasized and observed as compared with FIG.

Next, in the eighth embodiment, the distance of the optical fiber cable 11 is about 1 km (for example, 1000 m), about 8.6 km (for example, 8660 m), and about 15 km (for example, 15030 m). For the detection data near the time when the temperature change occurred, the data processing related to the distance is omitted. First, in the data processing related to time, the sampling time is set to 30 seconds, and the time points included in the data processing range _RT The number was set to 10 points (corresponding to a time of 5 minutes), the first moving average process was performed on the detected data, and the first time processed data was generated. Next, with respect to the first time processing data, the sampling time and the number of points of time included in the data processing range _RT are set to the same value as the first moving average processing, and the second moving average Processing was performed to generate second time processed data.
Then, in the process of calculating the amount of time change in temperature, a predetermined point data reference process is performed on the second time process data using the second time process data at the point of time one point before as a reference temperature. Then, temperature processing data was generated.
FIGS. 15A to 15C show detection results by the temperature sensor 41 arranged in the submerged portion 11a together with the detection data, the second time processing data, and the temperature processing data for each distance.

Further, in the eighth embodiment, the data processing related to the distance is not omitted. In the data processing related to the distance, the sampling distance is set to 2 m, and the number of distance points included in the data processing range _RL is set to 10 points (20 m In the ninth embodiment, the distance median data is generated by executing the moving median value acquisition process on the detected data.
FIGS. 16A to 16C show the detection results by the temperature sensor 41 arranged in the submerged portion 11a together with the distance processing data, the second time processing data, and the temperature processing data for each distance.

Further, in the data processing relating to the distance in the ninth embodiment, the number of distance points included in the data processing range _RL is set to 30 points (corresponding to a distance of 60 m), and the moving median value for the detected data is set. The case where the acquisition processing is executed and the distance processing data is generated is defined as the tenth embodiment.
FIGS. 17A to 17C show the detection results by the temperature sensor 41 arranged in the submerged portion 11a together with the distance processing data, the second time processing data, and the temperature processing data for each distance.

Furthermore, in the data processing relating to the distance in the tenth embodiment, the number of distance points included in the data processing range _RL is set to 40 points (corresponding to a distance of 80 m), and the moving median value for the detected data is set. The case where the acquisition processing is executed and the distance processing data is generated is defined as the eleventh embodiment.
FIGS. 18A to 18C show the detection results by the temperature sensor 41 arranged in the submerged portion 11a together with the distance processing data, the second time processing data, and the temperature processing data for each distance.

From these detection results, first, as shown in, for example, FIGS. 15A to 15C, the detection data output from the first optical pulse tester 13 is increased as the distance of the optical fiber cable 11 increases. It can be seen that the error increases.
Further, for example, as shown in FIGS. 16 (a), (b), (c) to FIGS. 18 (a), (b), (c), in particular, as shown in FIGS. Even when the distance of the fiber cable 11 is relatively long, the number of executions of data processing relating to time is set to an appropriate number according to the distance of the optical fiber cable 11 (for example, the ninth embodiment to the ninth embodiment). In the eleventh embodiment, it is found that a desired temperature change state such as a supercooling phenomenon can be extracted more clearly by setting twice instead of once.

In addition, even when the error of the time processing data increases as the distance of the optical fiber cable 11 increases, the number of distance points included in the data processing range _RL in the data processing related to the distance is For example, by setting an appropriate value according to the distance of the optical fiber cable 11 (for example, increasing in the ninth to eleventh embodiments), the state of a desired temperature change such as a supercooling phenomenon can be further improved. It can be seen that it can be extracted clearly.

According to the optical fiber cable deterioration detection system 10 according to the present embodiment, the return light of the incident light from the first optical pulse tester 13 is observed for each optical fiber in the optical fiber cable 11. Data processing relating to distance, data processing relating to time, and processing for calculating a temporal change in temperature are sequentially executed on the detection data, and temperature processing data is calculated, so that the data in the optical fiber cable 11 can be appropriately selected. The desired temperature change state at the position can be detected with high accuracy.
Thereby, for example, it is possible to easily detect a deterioration state such as the occurrence of water in the optical fiber cable 11 while preventing the deterioration state of the optical fiber cable 11 from being promoted. In addition, the deteriorated portion in the optical fiber cable 11 can be grasped based on the return time of the return light to the first optical pulse tester 13, and the repair work of the optical fiber cable 11 can be easily performed. .

  In the above-described embodiment, the temperature processing data is calculated based on the detection data output from the first optical pulse tester 13 that detects the intensity distribution of the Raman scattered light. Detection data output from the second optical pulse tester 14 that detects the intensity distribution of the Brillouin scattered light included in the return light, or a third optical pulse tester 15 that detects the intensity distribution of the Rayleigh scattering included in the return light, for example. The processing data may be calculated based on the detection data output from.

In the above-described embodiment, the control device 16 converts the detection result of the temperature distribution according to the distance in the longitudinal direction of the optical fiber output from the first optical pulse tester 13 into detection data acquired as time series data. On the other hand, for example, as shown in FIG. 2, data processing related to distance in the distance direction data processing unit 31, data processing related to time in the time direction data processing unit 32, and temperature change in the temperature change amount calculation unit 33 are sequentially performed. Although data processing is executed, the present invention is not limited to this, and each data processing may be executed in an appropriate order.
That is, for the detection data output from the first optical pulse tester 13, first, any one of the data processing regarding the distance, the data processing regarding the time, and the data processing regarding the temperature change is executed. 1 processing data is generated (step S31).
Next, any one of the data processing related to the distance, the data processing related to the time, and the data processing related to the temperature change is executed on the first processing data, and the second processing data is executed. Is generated (step S32).
Next, any one of the data processing related to the distance, the data processing related to the time, and the data processing related to the temperature change is executed on the second processing data, and the third processing data is executed. Is generated (step S33).
Next, based on the third processing data, it is determined whether or not a predetermined temperature change state, for example, a temperature change due to a supercooling phenomenon has occurred, and inundation into the optical fiber cable 11 is performed according to the determination result. The presence or absence of occurrence is detected (step S34).
Next, the determination result in step S34 is output to, for example, the output device 18 of the detection-side terminal device 10a or the output device 24 of the control-side terminal device 10b (step S35), and the series of processes is terminated.

1 is a configuration diagram of an optical fiber cable deterioration detection system according to an embodiment of the present invention. FIG. It is a flowchart which shows operation | movement of the degradation detection system of the optical fiber cable shown in FIG. It is a flowchart which shows the operation | movement which selects the data processing regarding distance. It is a flowchart which shows the operation | movement which selects the data processing regarding time. It is a flowchart which shows the operation | movement which selects the process which calculates the time variation | change_quantity of temperature. It is a block diagram of the degradation detection system of the optical fiber cable which concerns on the 1st-11th Example. It is a graph which shows the temperature processing data in 1st Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 1st Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 2nd Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 3rd Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 4th Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 5th Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 6th Example, and the detection result by each sensor. It is a graph which shows the temperature processing data in 7th Example, and the detection result by each sensor. It is a graph which shows the detection result by the temperature sensor arrange | positioned with a detection data, 2nd time process data, and temperature process data with respect to each distance in 8th Example with a water immersion part. It is a graph which shows the detection result by the temperature sensor arrange | positioned with a distance process data, 2nd time process data, and temperature process data with respect to each distance in 9th Example with a water immersion part. It is a graph which shows the detection result by the temperature sensor arrange | positioned in a water immersion part with distance processing data, 2nd time processing data, and temperature processing data for every distance in 10th Example. It is a graph which shows the detection result by the temperature sensor arrange | positioned in a water immersion part with distance processing data, 2nd time processing data, and temperature processing data for every distance in 11th Example.

Explanation of symbols

10 optical fiber cable deterioration detection system, 11 optical fiber cable, 13 first optical pulse tester (optical pulse tester), 14 second optical pulse tester (optical pulse tester), 15 third optical pulse tester ( Optical pulse tester), 31 distance direction data processing section (distance smoothing means), 32 time direction data processing section (time smoothing means), 33 temperature change amount calculation section (temperature change calculation means), 34 inundation determination section ( Degradation judgment means)

Claims (9)

A light pulse is incident on the optical fiber in the optical fiber cable (11) from the incident end, and the temperature distribution in the longitudinal direction of the optical fiber cable is time-sequentially by the predetermined scattered light included in the return light returned to the incident end. An optical pulse tester (13) to detect as data;
Detection data consisting of the time-series data of the temperature distribution in the longitudinal direction of the optical fiber cable output from the optical pulse tester or data relating to the detection data as processing target data,
A distance smoothing means (31) for performing a smoothing process on a distance in a predetermined range in the longitudinal direction of the optical fiber cable and generating distance smoothed data for the processing target data;
A time smoothing means (32) for performing a smoothing process on the processing target data with respect to a predetermined range of time of the time-series data and generating time-smoothed data;
A temperature change amount calculation means (33) for calculating data of a time change amount of the temperature distribution in the longitudinal direction of the optical fiber cable with respect to the processing target data;
In the data of the time change amount of the temperature distribution in the longitudinal direction of the optical fiber cable calculated by the temperature change amount calculating means, by determining whether or not a temperature change due to a supercooling phenomenon has occurred, A deterioration determining means (34) for determining the presence or absence of water in the optical fiber cable,
In the data of the time change amount of the temperature distribution, the deterioration determination unit is configured to change the temperature due to a supercooling phenomenon when the temperature of the optical fiber cable is temporarily lowered and raised by a predetermined amount after the temperature drops below the freezing point of water. An optical fiber cable deterioration detection system characterized in that it can be determined as follows . 2. The optical fiber cable deterioration detection system according to claim 1, wherein the distance smoothing unit sets the distance in the predetermined range according to information on the distance of the optical fiber cable in the processing target data.   The optical fiber cable deterioration detection system according to claim 1, wherein the time smoothing unit performs the smoothing process a plurality of times on the processing target data. 4. The optical fiber cable deterioration detection according to claim 3, wherein the time smoothing unit sets the number of times the smoothing process is performed according to information on the distance of the optical fiber cable in the processing target data. 5. system.   The optical fiber according to any one of claims 1 to 4, wherein the smoothing process is an average value calculation process, a moving average value calculation process, a median value calculation process, or a moving median value calculation process. Cable deterioration detection system.   The optical fiber cable degradation detection system according to any one of claims 1 to 5, wherein the temperature change amount calculation means calculates a difference in the processing target data with respect to a predetermined reference temperature.   The temperature change amount calculation means is configured to store the processing target data that is a predetermined time or a predetermined number of times earlier than the processing target data to be the difference calculation target among the plurality of processing target data forming a time series. The deterioration detection system for an optical fiber cable according to claim 6, wherein the system is set as a reference temperature for the optical fiber cable. The deterioration of the optical fiber cable according to claim 7, wherein the temperature change amount calculation unit sets the predetermined time or the predetermined number according to information on a distance of the optical fiber cable in the processing target data. Detection system.   In the time variation data of the temperature distribution in the longitudinal direction of the optical fiber cable calculated by the temperature variation calculation means, depending on the specific heat in the longitudinal direction of the optical fiber cable or the distribution of state quantities related to the specific heat A deterioration determining means (34) for determining the presence or absence of water in the optical fiber cable by determining whether or not a time delay with respect to an appropriate temperature change has occurred. The optical fiber cable deterioration detection system according to claim 8.

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