Location system

Abstract

To provide an orientation system which has high positioning accuracy of a failure generation position of a power cable.SOLUTION: An orientation system 100 for orienting an accident point of a power cable 4 includes an optical fiber cable 41 which is installed in parallel with the power cable 4, an orientation master unit 2, an orientation slave unit 3 and an information processing device 1. The orientation master unit 2 includes a transmission device 22 that makes light incident on one end of one optical fiber cable 41a to transmit it. The orientation slave unit 3 includes a branching device 32 that branches light emitted from the other end, and makes the light incident on one end of the other optical fiber cable 41b of the pair of optical fiber cables 41. The orientation master unit 2 includes a master unit reception device 23 which receives the emission light emitted from the other end. The information processing device 1 includes: an emission control unit 101 which emits light; a reception light change reception unit 102 which receives the time change of the intensity of the received light; and an accident point derivation unit 103 which derives an accident point A on the basis of the time of change in the intensity of the received light and the propagation speed of the light.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a calibration system.

Background Art

[0002] When calibrating the accident location of a submarine electric cable, for example, in the case of a major accident such as a break in the electric cable itself, there is a calibration device. However, it is difficult to detect and identify the accident location in advance before a major accident occurs. Particularly in the case of submarine cables, they may be caught by an anchor, lifted, and then released, resulting in a bent state, which may lead to actual accidents such as leakage or breakage over time. However, when such an actual accident occurs, it is often impossible to identify the ship or the like that induced the resulting bend, so compensation claims and the like have often not been possible until now.

[0003] As a countermeasure, for example, a method of recording ships with images and recording ships staying for a certain period of time or more has been adopted. However, although it has a certain effect in coastal areas such as the Seto Inland Sea, in the future's offshore wind power generation that is envisioned, the distance is far, the area is extensive, and it is predicted that clear images cannot be obtained due to fog, weather, etc.

[0004] Conventionally, technologies for detecting the time point when distortion occurs in a power cable have been developed. For example, Patent Document 1 discloses a technology of attaching an optical fiber cable provided with a grating to a power cable. Based on the reflection spectrum from the fiber Bragg grating provided in the optical fiber cable, distortion and / or temperature are monitored, and damage to the power cable is verified.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The technology disclosed in Patent Document 1 requires a special optical fiber cable with gratings to be attached to a power cable. Multiple gratings with different reflection wavelengths are provided, and distortion at multiple locations is verified. Therefore, the fineness of detection of the distorted area depends on the gap between the gratings. For a power cable several kilometers long, if accuracy to the nearest meter is required, for example, the gratings must be placed at 1-meter intervals. In this case, it would be impractical to place thousands of gratings over several kilometers. Consequently, for example, the gap between the gratings must be in units of 10 meters, meaning the positional accuracy must also be in units of 10 meters.

[0007] The present invention aims to provide a power cable fault location detection system with high accuracy. [Means for solving the problem]

[0008] To achieve the above objective, one aspect of the present invention is a location system for locationating the location of a fault in a power cable, comprising a pair of optical fiber cables installed parallel to the power cable, a location master unit, a location slave unit, and an information processing device, wherein the location master unit has a transmitting device that transmits light by injecting it into one end of one of the pair of optical fiber cables, the location slave unit has a branching device that branches the light emitted from the other end of one of the optical fiber cables and injects it into one end of the other optical fiber cable of the pair, the location master unit has a master receiving device that receives the emitted light that is injected into one end of the other optical fiber cable and emitted from the other end of the other optical fiber cable, and the information processing device comprises an emission control unit that causes the transmitting device to emit light, a received light change receiving unit that receives the time change in the intensity of the light received by the master receiving device, and a fault location derivation unit that derives the fault location that occurred in the pair of optical fiber cables based on the time of change in the intensity of the received light received by the received light change receiving unit and the propagation speed of light in the pair of optical fiber cables. [Effects of the Invention]

[0009] According to the present invention, a location system with high accuracy in determining the location of faults in power cables is provided. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the hardware configuration of the location system of the present invention. [Figure 2] This is a schematic diagram illustrating how a power cable failure, which is verified by the location detection system of the present invention, is caused by a ship. [Figure 3] A block diagram showing the functional configuration of the localization system of the present invention. [Figure 4] This is a block diagram showing the hardware configuration of an information processing device related to the localization system of the present invention. [Figure 5] This is a block diagram showing the functional configuration of an information processing device related to the location system of the present invention. [Figure 6] This figure shows the relationship between the time evolution of the optical signal and the cause of the accident in the orientation system of the present invention. [Figure 7] This figure shows the relationship between the time change of the optical signal and the propagation state of light in the optical fiber cable when bending occurs in the power cable and the light propagation intensity decreases, in the positioning system of the present invention. [Figure 8] This figure shows the relationship between the time change of the optical signal when a break occurs in the optical fiber cable and the propagation state of light within the optical fiber cable in the location system of the present invention. [Figure 9] This figure shows the relationship between the time change of the optical signal and the propagation state of light in the optical fiber cable when an electrical problem occurs in a repeater or the like of an optical fiber cable in the localization system of the present invention and then recovers. [Modes for carrying out the invention]

[0011] Hereinafter, a leveling system 100 according to an embodiment of the present invention will be described with reference to the drawings. In each figure, the same components are denoted by the same reference numeral. When the same components are distinguished as a first component, a second component, etc., the reference numeral a, b, etc., is added.

[0012] Figure 1 is a schematic diagram showing the overall hardware configuration of the location tracking system 100. The location tracking system 100 includes a pair of optical fiber cables 41 grounded in parallel with the power cable 4, a location tracking master unit 2, a location tracking slave unit 3, and an information processing device 1. The location tracking system 100, for example, tracks the location of damage to the power cable 4 attached to the seabed. In the example shown in Figure 1, for example, the receiver 5a at the land-based power receiving base station 6a receives power generated by the generator 5b at the offshore wind power station 6b through the power cable 4 attached to the seabed.

[0013] Figure 2 is a schematic diagram illustrating how a malfunction in the power cable 4, which is verified by the location system 100 of the present invention, is caused by a ship 7. As shown in Figure 2(a), the ship 7 drops anchor 71 to dock. The anchor 71 gets caught on the power cable 4. Next, as shown in Figure 2(b), the ship 7 raises the anchor 71 to move. At this time, the power cable 4 is lifted. Once the anchor 71 has been raised to a certain extent, the power cable 4 detaches from the anchor 71, as shown in Figure 2(c). Ship 7 stows its anchor 71 and sails away from the anchoring accident site as shown in Figures 2(d) and 2(e), as shown in Figure 2(f). As shown in Figure 2(d), the power cable 4 is pulled up and slowly sinks as shown in Figure 2(e), becoming twisted by the twisting of the power cable 4 and the ocean currents. As shown in Figure 2(f), the power cable 4 may become folded with a small curvature due to the influence of ocean currents, etc.

[0014] The folded portion is subjected to stress, which can cause physical damage to the power cable 4. This can lead to electrical leakage. In addition, the resistance of the power cable 4 in the folded portion increases, causing heat to be generated, which can lead to accidents such as melting the insulation of the power cable 4.

[0015] The calibration system 100 according to the present invention accurately calibrates the time of occurrence of an event and the accident location A at the time when the state shown in FIGS. 2(b) to 2(f) is reached before the occurrence of an accident such as electric leakage or coating dissolution as described above.

[0016] FIG. 3 is a block diagram showing the functional configuration of the calibration system 100. The calibration system 100 includes a pair of optical fiber cables 41 composed of a calibration master unit 2, a calibration slave unit 3, one optical fiber cable 41a, and the other optical fiber cable 41b, and an information processing device 1.

[0017] The calibration master unit 2 includes a transmission device 22 that emits infrared laser light, a master unit receiving device 23 that receives the laser light, and a master unit processing device 21 that controls the transmission device 22 and the master unit receiving device 23. The calibration slave unit 3 includes a branching device 32 for laser light, a slave unit receiving device 33, and a slave unit processing device 31 that controls the branching device 32 and the slave unit receiving device 33.

[0018] The transmission device 22 is controlled by the master unit processing device 21 to emit, for example, infrared laser light by making it incident on one end of one optical fiber cable 41a of the pair of optical fiber cables 41. Although details will be described later, there are cases where the intensity is changed in a predetermined pattern, for example, in a pulsed shape, and cases where laser light of a constant intensity is emitted. The branching device 32 included in the calibration slave unit 3 is, for example, a half mirror formed by aluminum evaporation. The light emitted from the other end of one optical fiber cable 41a is branched by the branching device 32. One of the branched laser lights is made incident on one end of the other optical fiber cable 41b of the pair of optical fiber cables 41 and is incident on the master unit receiving device 23 included in the calibration master unit 2 from the other end of the other optical fiber cable 41b. The other branched laser light is incident on the slave unit receiving device 33 via the slave unit optical fiber cable 42 in the calibration slave unit.

[0019] The master receiver 23 sends the laser beam reception signal to the master processing unit 21. The master processing unit 21 receives the information from the master receiver 23. The master processing unit 21 has a first clock and associates it with the time when the master receiver 23 received the information. The slave receiver 33 sends the laser beam reception signal to the slave processing unit 31. The slave processing unit 31 has a second clock and associates it with the time when the slave receiver 33 received the information.

[0020] The information processing device 1 controls the master processing device 21 and the slave processing device 31.

[0021] Figure 4 shows the hardware configuration of the information processing device 1. As shown in Figure 4, the information processing device 1 comprises a control unit 10, an input / output unit 16, a communication means 17, and a storage unit 18. The control unit 10 has a processor 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a bus 14, and an input / output interface 15. The information processing device 1 may be a general-purpose personal computer capable of performing various functions by installing various programs, or it may be a computer embedded in dedicated hardware.

[0022] The processor 11 performs various calculations and processes. The processor 11 is, for example, a CPU (central processing unit), MPU (micro processing unit), SoC (system on a chip), DSP (digital signal processor), GPU (graphics processing unit), ASIC (application specific integrated circuit), PLD (programmable logic device), or FPGA (field-programmable gate array). Alternatively, the processor 11 is a combination of several of these. Furthermore, the processor 11 may be a combination of these with hardware accelerators, etc.

[0023] The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. The processor 11 performs various processes according to the program recorded in ROM 12 or the program loaded into RAM 13. Part or all of the program may be incorporated into the circuitry of the processor 11.

[0024] Bus 14 is also connected to input / output interface 15. An input / output unit 16, a communication means 17, and a storage unit 18 are connected to the input / output interface 15.

[0025] The input / output unit 16 is electrically connected to the input / output interface 15 by wire or wireless connection. The input / output unit 16 consists of, for example, an input unit such as a keyboard and mouse, and an output unit such as a display for displaying images and a speaker for amplifying sound. The input / output unit 16 may also have an integrated configuration of display and input functions, such as a touch panel.

[0026] The communication means 17 is a device for the processor 11 to communicate with the master unit processing unit 21 and the slave unit processing unit 31, for example, via a wired connection or a network such as the Internet (not shown). The storage unit 18 is a storage device such as a hard disk drive (HDD) or solid-state drive (SSD) that stores a program for controlling the positioning system 100, the length of a pair of optical fiber cables 41, a predetermined signal strength for determining the signal state acquired from the master unit processing unit 21 or the slave unit processing unit 31, and past accident occurrences.

[0027] The hardware configuration shown in Figure 4 is merely an example and is not limited to this configuration. In addition to being composed of various processing units such as single processors, multiprocessors, and multicore processors, a combination of these various processing units and processing circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field-Programmable Gate Arrays) may be adopted to realize the functional configuration of a processor. The information processing device 1 does not have a storage unit 18, but rather a configuration in which a storage unit 18 is provided separately may be adopted.

[0028] Figure 5 is a block diagram showing the functional configuration of the information processing device 1 according to this embodiment. Each function shown in Figure 5 is realized by the processor 11 and other components of the information processing device 1 shown in Figure 4. The information processing device 1 includes an output control unit 101, a received light change reception unit 102, and a fault location derivation unit 103. The output control unit 101 causes the transmitting device 22 to emit laser light. The received light change reception unit 102 receives the time change in the intensity of the light received by the master receiving device 23. The fault location derivation unit 103 derives the fault location A that occurred in the pair of optical fiber cables 41, i.e., the fault location A that occurred in the power cable 4, based on the time of change in the intensity of the received light received by the received light change reception unit 102 and the propagation speed of light in the pair of optical fiber cables 41.

[0029] Referring to Figures 6 to 9, we will explain how the fault location identification unit 103 identifies fault location A. Figure 6 is a diagram showing the relationship between the time change of the optical signal in the location system 100 and the cause of the fault. Figures 7 to 9 are diagrams showing the relationship between the time change of the optical signal in the location system 100 of the present invention and the propagation state of light in the optical fiber cable.

[0030] Unless otherwise instructed, the emission control unit 101 sends an instruction to the master processing unit 21, which then emits light of a certain intensity from the transmitting device 22, as shown in the column labeled "Normal" in Figure 6. In Figure 6, the intensity is set to 100. The light emitted from the transmitting device 22 propagates through one optical fiber cable 41a, passes through the branching device 32, and is partially received by the slave receiving device 33. Due to attenuation caused by transmission loss (losses in the core wire, connections, and branches) during propagation through one optical fiber cable 41a, the intensity is shown as 90 in Figure 6. The light emitted from the transmitting device 22 propagates through one optical fiber cable 41a, passes through the branching device 32, and propagates through the other optical fiber cable 42b, which is received by the master receiving device 23. The propagated light is attenuated during propagation through the other optical fiber cable 42b. When the master receiver 23 receives a signal, the transmission loss of the optical cable (losses in the core wire, connections, and branches) is incurred during the round trip between the target master unit 2 and the target slave unit 3, so an attenuation twice the attenuation at the slave receiver 33 is expected. In Figure 6, the attenuation is set to 20 (twice 10), and the intensity is expressed as 80. More precisely, the light is branched at the branching device 32, and the intensity of the light incident on the slave receiver 33 and the master receiver 23 decreases. To simplify the principle, in this specification, the ratio of the intensities of the branched light is not considered, and it is simplified to assume that the intensity of the light before branching is maintained at both ends after branching.

[0031] The fault location derivation unit 103 determines and synchronizes the time difference between the first clock of the master unit processing unit 21 and the second clock of the slave unit processing unit 31, and derives the optical propagation speed in the pair of optical fiber cables 41. Based on this synchronization and optical propagation speed, the fault location A is derived. The method of synchronization and the derivation of the optical propagation speed will be explained below. In the following explanation, times are distinguished as first time T1, second time T2, etc. T1, T2, etc. are codes that distinguish times and also represent numerical values ​​corresponding to the times. In addition, in the following explanation, distances are distinguished as L1 for the distance between the master and slave units, and L2 for the distance from fault location A to the localized master unit 2, etc. L1, L2, etc. are codes that distinguish distances and also represent numerical values ​​corresponding to the distances.

[0032] As shown in the column labeled "Time Synchronization" in Figure 6, the master unit 21 resets the first clock and sends a predetermined signal pattern as the output of light emitted from the transmitter 22 to one of the optical fiber cables 41a, so that it is clear that it is a time synchronization signal. In the example shown in Figure 6, the output of the emitted light is reduced in a pulsed manner. This time is received by the master unit 21 as the first time T1. In Figure 6, the laser light with an intensity of 100 is reduced in a pulsed manner to an intensity of 0. The pulsed signal propagates through one of the optical fiber cables 41a and is branched at the branching device 32. One of the lights is received by the slave unit receiving device 33. The slave unit receiving device 33 had been receiving a signal with a constant intensity of 90, but at the second time T2 it receives a signal with a pulsed decrease in intensity. At this second time T2, the slave unit 31 resets the second clock. The other light branched at the branching device 32 propagates through the other optical fiber cable 41b and is received by the master unit receiving device 23. This time is received as the third time T3 by the first clock of the master unit processing device 21.

[0033] Based on the first time interval, T3-T1, from when the transmitting device 22 emits pulsed light until the master receiving device 23 receives the pulsed light, and the parent-child distance L1, which is the distance between one end and the other of a pair of optical fiber cables 41 that is known in advance, the fault location derivation unit 103 calculates the propagation speed of light in the pair of optical fiber cables 41 using the following equation (1). Propagation speed = Parent-child distance (L1) / (First time (T3-T1) / 2) Equation (1)

[0034] The first clock is reset at the first time T1, and the second clock is reset at the second time T2. Light propagates through the transmitter 22, the branching device 32, and the master receiver 23, so it travels back and forth between the localization master 2 and the localization slave 3. Therefore, T3-T1 is the round-trip time, and T2-T1 is half of that time. Since T3-T1 is accurately measured by the first clock, T2-T1 is accurately determined. This allows the time difference between the reset times of the second clock and the first clock to be determined. It is detected that the time indicated by the second clock is behind the time indicated by the first clock by half of this time difference, and the first and second clocks are synchronized.

[0035] In the following explanation, the first and second clocks are assumed to be synchronized and, unless otherwise specified, to be keeping the same time.

[0036] Let's explain the case where an accident occurs in which the power cable 4 is lifted by the ship 7, as shown in Figure 2. When the above accident occurs, there is a high possibility that the power cable 4 will bend, as shown in Figure 2(f). At this time, the optical fiber cable 41, which is arranged in parallel with the power cable 4, will also bend in the same way. In the optical fiber cable 41, light propagates by total internal reflection between the core and the cladding. If the core, which is the core wire, is bent or compressed, the conditions for total internal reflection are broken, and the propagation intensity decreases. Consequently, the signal levels received by the master receiver 23 and the slave receiver 33 decrease. Using the time when this signal level changes, the accident location derivation unit 103 derives the accident location A.

[0037] When the bending shown in Figure 2(f) occurs, the received light intensity of the slave receiver 33 decreases at the fourth time step T4, as indicated in the column for lifting accidents in Figure 6, and the received light intensity of the master receiver 23 decreases twice, at the fifth time step T5 and the sixth time step T6. This phenomenon will be explained with reference to Figure 7. Figure 7 is a diagram extracted from Figure 3, with the accident location A and the light propagation state added.

[0038] The fault location is set as A. At fault location A, the position of one optical fiber cable 41a is set as A1, and the position of the other optical fiber cable 41b is set as A2. When a fault occurs, the total internal reflection conditions are disrupted, and the signal level decreases.

[0039] As light propagates, the signal, whose level has decreased, reaches the slave receiver 33 and the master receiver 23. The light intensity propagating through one optical fiber cable 41a decreases, and after the fault, the light travels from the fault point A1 through the branching device 32a to the slave receiver 33 at the fourth time T4. As shown in Figure 6, the received light intensity at the slave receiver 33 decreases at the fourth time T4. As shown in Figure 7, the light intensity propagating through the other optical fiber cable 41b decreases at the fault point A2. Subsequently, the propagating light travels through the optical fiber cable 41b and reaches the master receiver 23 at the fifth time T5. As shown in Figure 6, the received light intensity at the master receiver 23 decreases at the fifth time T5. Meanwhile, the light whose intensity decreased at the fault point A1 is reflected by the branching device 32a, enters the other optical fiber cable 41b, and the propagating light intensity decreases again as it passes through the fault point A2. The propagating light then reaches the master receiver 23. This propagating light reaches the master receiver 23 via branching devices 32a and A2 from A1. Therefore, the propagating light reaches the master receiver 23 at the sixth time T6, which is later than the fourth time T4 and the fifth time T5. Figure 6 shows that the received light intensity at the master receiver 23 decreases further at the sixth time T6.

[0040] The fault location derivation unit 103 identifies the location of fault location A in two ways based on the values ​​of the fourth time point T4, the fifth time point T5, and the sixth time point T6. The optical propagation speed in the optical fiber cable 41 has been determined in advance using the method described above and is stored in the storage unit 18.

[0041] In the first method, the time when the master receiver 23 detects light of an intensity weaker than a predetermined first intensity and below a predetermined intensity is defined as the fifth time T5, and the time when the master receiver 23 detects light of a predetermined intensity weaker than the intensity of light detected at the fifth time T5 is defined as the sixth time T6, and the fault location derivation unit 103 determines the fault location based on the second time period (T6-T5) between the fifth time T5 and the sixth time T6, The distance from the ground control unit 3 to accident site A can be calculated based on the following equation (2). Distance from the localization device 3 at accident site A = 2nd time (T6-T5) × propagation speed / 2 Formula (2) Although it is stated that the intensity is below a predetermined intensity, this can refer to absolute intensity or relative intensity. The same applies hereafter. In Figure 6, the light of the predetermined intensity mentioned above corresponds to light of intensity 80. Referring to Figure 7, between the fifth time T5 and the sixth time T6, the light travels back and forth between the fault site A and the branching device 32 of the localization slave unit 3. By multiplying this time by the speed of light propagation and dividing by 2, the distance from the localization slave unit 3 to the fault site A can be determined. In this first method, the second clock of the slave unit processing unit 31 is not involved, and the calculation is performed only by the master unit processing unit 21. For this reason, the fault site A can be identified even if the synchronization between the first clock and the second clock is incomplete.

[0042] In the second method, it is assumed that the first clock and the second clock are synchronized. The fault location derivation unit 103 sets the time when the master receiver 23 detects light of an intensity weaker than a predetermined second intensity (T5 in Figure 6) as the fifth time, and the time when the slave receiver 33 detects light of an intensity weaker than a predetermined third intensity (T4 in Figure 6) as the fourth time, and derives the distance of fault location A from the localization master unit 2 based on the following equation (3). Distance from the location sensor 3 at accident site A = ((Distance L1 between the base station and the slave station) - (5th time zone T5 - 4th time zone T4) × propagation speed) / 2 Formula (3) Although it is stated that the intensity is weaker than a specified level, both absolute and relative intensity can be considered. The same applies below. The derivation of equation (3) will be explained with reference to Figure 7. Let L2 be the distance from fault location A to the main control unit 2, and L3 be the distance from fault location A to the sub-control unit. For the sake of simplifying the derivation, assume that the time when the fault occurred is 0, that a weak intensity light reaches the sub-control unit 3 at the fourth time step T4, and that a weak intensity light reaches the main control unit 2 at the fifth time step T5. At this time, T5 × propagation speed = L2 T4 × propagation speed = L3 Subtracting this from both sides, (T5-T4) × propagation velocity =L2-L3 This is the result. This equation represents the time between the 5th time T5 and the 4th time T4, so the assumption that the time when the accident occurred is 0 is actually unnecessary. The distance L1 between the base station 2 and the base station 3 is known in advance from the map or the length of the power cable 4. Since L1 = L2 + L3, and the unknown values ​​are L2 and L3, equation (3) can be obtained by solving the system of equations consisting of the two equations.

[0043] As shown in Figure 6, a disconnection accident in which the optical fiber cable 41 is broken is a possible scenario. In this case, as shown by the dotted line associated with T6 in Figure 7, there is no propagating light, and as shown in Figure 8, there are only signals going from the fault location A to the localization slave unit 3 and signals going from the fault location A to the localization master unit 2. As shown in the disconnection accident column in Figure 6, the slave unit receiver 33 detects that the signal is interrupted and its intensity becomes 0 at the 7th time step T7, and the master unit receiver 23 detects that the propagation is interrupted and its intensity becomes 0 at the 8th time step T8. This situation is similar to the situation in which the 4th time step T4 and the 5th time step T5 were used to identify the fault location A in the lifting accident described above, except that the received signal intensity drops to 0. Therefore, in equation (3), by replacing the 5th time step T5 with the 8th time step T8 and the 4th time step T4 with the 7th time step T7, the distance between the fault location A and the localization slave unit 3 can be derived.

[0044] In a power cable 4 and an optical fiber cable 41 grounded parallel to the power cable 4, an electrical fault is anticipated in the optical fiber cable 41 due to an accident caused by a ship 7, as shown in Figure 2. Although the optical fiber cable 41 is generally suitable for long-distance communication, repeaters are installed to compensate for the inherent losses of optical fiber cables. It is anticipated that an accident caused by a ship 7, as shown in Figure 2, could cause a malfunction in this repeater, resulting in a weakening or complete interruption of the optical propagation intensity. It is also anticipated that the malfunction could be electrically restored.

[0045] The time variation of the signal is shown in the column labeled "Electrical Fault" in Figure 6. In cases where the intensity of light propagation weakens or is interrupted, the fourth time point T4, the fifth time point T5, and the sixth time point T6 can be set, similar to the case of a lifting fault. The location of fault point A can be determined by using equations (2) and (3). Conversely, an explanation is given for cases where the electrical system is restored and the intensity of light propagation is restored.

[0046] In the column labeled "electrical fault" in Figure 6, the signal strength of the slave receiver 33 recovers at the 9th time T9, and the signal strength of the master receiver 23 recovers at the 10th time T10. This situation will be explained with reference to Figure 9. The signal recovers at fault location A1, and at the 9th time T9, the slave receiver 33 detects light with an intensity stronger than a predetermined 4th intensity. The signal recovers at fault location A2, and at the 10th time T10, the master receiver 23 detects light with an intensity stronger than a predetermined 5th intensity. Here, as shown by the dotted line in Figure 9, a portion of the recovered light is reflected by the branching device 32 of the localized slave unit 3, passes through fault location A2, and is received by the master receiver 23. Here, since the malfunction at fault location A2 has already been resolved, the light intensity does not change when passing through fault location A2. Therefore, as shown in Figure 6, the received light intensity of the slave receiver 33 and the master receiver 23 increases only once each. In this situation, the accident site A is identified by the 9th time zone T9 and the 10th time zone T10.

[0047] The accident location derivation unit 103 sets the time when the master receiver 23 detects light with an intensity stronger than a predetermined fourth intensity as the tenth time T10, and the time when the slave receiver 33 detects light with an intensity stronger than a predetermined fifth intensity as the ninth time T9, and derives the distance of accident location A from the localization master unit 2 based on the following equation (4). Distance from the location sensor 3 at accident site A = ((Distance between base station 2 and base station 3) - (10th time T10 - 9th time T9) × propagation speed) / 2 Formula (4) Although it was stated that it is stronger than a specified strength, both absolute and relative strengths are possible interpretations.

[0048] The derivation of equation (4) will be explained with reference to Figure 9. Let L2 be the distance from fault location A to the main control unit 2, and L3 be the distance from fault location A to the sub-control unit. Let TR (Time of Recovery) be the time when the fault was recovered. The time of fault recovery TR is different from the recovered signal items T9 and T10. At this time, (T9-TR) × propagation speed = L3 (T10-TR) × propagation speed = L2 By subtracting from both sides, the TR term disappears. (T9-T10) × propagation speed = L3-L2 The following is derived. The distance L1 between the base station 2 and the base station 3 is known in advance from the map or the length of the power cable 4. Since L1 = L2 + L3, and the unknown values ​​are L2 and L3, equation (4) can be obtained by solving the system of equations consisting of the two equations.

[0049] In the above description, the first clock and the second clock were synchronized within a closed system of the orientation system 100. The first clock and the second clock may also be synchronized based on the time of an atomic clock received from satellite radio waves.

[0050] This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of the disclosure are considered to be within the scope of the present invention.

[0051] The following effects are achieved according to the orientation system 100 according to the embodiment described above.

[0052] (1) A location system 100 for locating the fault location A of a power cable 4, comprising a pair of optical fiber cables 41 installed parallel to the power cable 4, a location master unit 2, a location slave unit 3, and an information processing device 1, wherein the location master unit 2 has a transmitting device 22 that transmits light by injecting it into one end of one of the optical fiber cables 41a of the pair of optical fiber cables 41, and the location slave unit 3 has a branching device 32 that branches the light emitted from the other end of one of the optical fiber cables 41a and injects it into one end of the other optical fiber cable 41b of the pair of optical fiber cables 41, and the location master unit 2 transmits the other light The localization system 100 includes a master receiving device 23 that receives emitted light incident on one end of fiber cable 41b and emitted from the other end of the other optical fiber cable 41b, and the information processing device 1 includes an emission control unit 101 that causes a transmitting device 22 to emit light, a received light change receiving unit 102 that receives changes in the intensity of the light received by the master receiving device 23 over time, and a fault location derivation unit 103 that derives a fault location A that occurred in the pair of optical fiber cables 41 based on the time of change in the intensity of the received light received by the received light change receiving unit 102 and the propagation speed of light in the pair of optical fiber cables 41.

[0053] This provides a highly accurate positioning system 100 for determining the location of faults in the power cable 4. The location of a bend occurring at any given point can be identified.

[0054] (2) The output control unit 101 emits pulsed light from the transmitting device 22 and, based on the first time from when the transmitting device 22 emits pulsed light until the master receiving device 23 receives the pulsed light, and the master-child distance which is the distance from one end to the other of the pair of optical fiber cables which is known in advance, calculates the propagation speed of light in the pair of optical fiber cables based on the following equation (1): Propagation speed = distance between parent and child / (1st time / 2) Equation (1) The leveling system 100 according to claim 1.

[0055] This allows for the identification of the propagation speed specific to the optical fiber cable 41, resulting in higher positioning accuracy.

[0056] (3) The emission control unit 101 emits light of a certain intensity to the transmitting device 22, and the time when the master receiving device 23 detects light of an intensity weaker than a predetermined first intensity is defined as the first time, and the time when the master receiving device 23 detects light of an intensity weaker than the light intensity detected at the first time is defined as the second time, and the fault location derivation unit 103 calculates the distance of fault location A from the localization slave unit 3 based on the second time between the first time and the second time, based on the following formula (2): Distance from the localization device 3 at accident site A = 2nd time × propagation speed / 2 Equation (2) The leveling system 100 according to claim 2.

[0057] This allows the location of accident site A to be determined using only the clock on the main control unit 2. Since there is no need to synchronize the first clock on the main control unit 2 with the second clock on the sub-control unit 3, measurement accuracy can be improved. Assuming the speed of light propagation is 300,000 kilometers per second, the time accuracy can be reduced to nanoseconds (10⁻¹⁰). -9 When the time is set to (seconds), the positional accuracy is 30 cm. Furthermore, it is possible to pinpoint any location where the optical fiber cable 41 is attached.

[0058] (4) The emission control unit 101 emits light of a certain intensity to the transmitting device 22, the localization master unit 2 has a first clock, the localization slave unit 3 has a second clock, the first clock and the second clock are synchronized, the branching device 32 branches the light, the localization slave unit 3 has a slave receiving device 33 that receives the branched light, the fault location derivation unit 103 sets the time when the master receiving device 23 detects light of an intensity weaker than a predetermined second intensity as the third time, the time when the slave receiving device 33 detects light of an intensity weaker than a predetermined third intensity as the fourth time, and derives the distance of fault location A from the localization master unit 2 based on the following equation (3). Distance from the location sensor 3 at accident site A =((Distance between base station 2 and base station 3)-(Third time point - Fourth time point)×Propagation speed) / 2 Formula (3) The leveling system 100 according to claim 2.

[0059] This makes it possible to pinpoint the location of the accident site A even if the optical fiber cable 41 is broken. Assuming the speed of light propagation is 300,000 kilometers per second, the time accuracy is nanoseconds (10⁻¹⁰). -9 When the time is set to seconds, the positional accuracy is 30 cm.

[0060] (5) The emission control unit 101 emits light of a certain intensity to the transmitting device 22, the localization master unit 2 has a first clock, the localization slave unit 3 has a second clock, the first clock and the second clock are synchronized, the branching device 32 branches the light, the localization slave unit 3 has a slave receiving device 33 that receives the branched light, the fault location derivation unit 103 sets the time when the master receiving device 23 detects light of an intensity stronger than a predetermined fourth intensity as the fifth time, the time when the slave receiving device 33 detects light of an intensity stronger than a predetermined fifth intensity as the sixth time, and derives the distance of fault location A from the localization master unit 2 based on the following equation (4). Distance from the location sensor 3 at accident site A =((Distance between base station 2 and base station 3)-(5th time step - 6th time step)×propagation speed) / 2 Formula (4) The leveling system 100 according to claim 2.

[0061] This makes it possible to pinpoint the location of the accident site A even after recovery from an electrical accident. Assuming the speed of light propagation is 300,000 kilometers per second, the time precision can be set to nanoseconds (10⁻¹⁰). -9 When the time is set to seconds, the positional accuracy is 30 cm.

[0062] (6) The base station 2 transmits a predetermined signal pattern to the base station 3 and simultaneously resets the time of the first clock. The base station 3 receives the predetermined signal pattern, splits the light, and emits it towards the base station 2 and simultaneously resets the second clock. The base station 2 receives the predetermined signal pattern, detects the time difference between the time of reception and the time of transmission, detects that the time shown on the second clock is behind the time shown on the first clock by half the time difference, and synchronizes the first clock and the second clock. A positioning system 100 according to any one of claims 3 to 5.

[0063] This allows the location of accident site A to be determined within a closed system with no external data input or output.

[0064] (7) The first clock and the second clock are synchronized based on the time of the atomic clock received from satellite radio waves. A positioning system 100 according to any one of claims 3 to 5.

[0065] The first clock and the second clock can be synchronized regardless of the change in the optical fiber cable 41, which is affected by changes in the cable's characteristics. [Explanation of Symbols]

[0066] 100 Location System 1. Information Processing Device 10 Control Unit 11 processors 12 ROM 13 RAM 14 bus 15 Input / Output Interfaces 16 Input / output section 17. Means of communication 18 Memory section 2 Orientation base unit 21 Master Unit Processing Unit 22 Transmitter 23 Master unit receiving device 24 The First Clock 3 Location subunit 31. Sub-unit processing unit 32 Branching device 33. Sub-unit receiving device 34 The Second Clock 4 Power Cables 41 Fiber Optic Cable - Cable 5a Power transmission equipment 5b Power receiving equipment 6a Land-based power receiving base 6b Offshore wind power base 7 Ships 71 Anchor 101 Injection Control Unit 102 Received light change reception unit 103 Accident site derivation section A Accident Site

Claims

1. A location system for locating the site of a power cable failure, A pair of optical fiber cables installed parallel to the aforementioned power cable, The base station and The location tracking device, It has an information processing device, The aforementioned location master unit has a transmitting device that transmits light by injecting it into one end of one of the pair of optical fiber cables. The location sub-unit has a branching device that branches the light emitted from the other end of one of the optical fiber cables and directs it into one end of the other optical fiber cable of the pair of optical fiber cables. The aforementioned location master unit has a master unit receiving device that receives emitted light that enters one end of the other optical fiber cable and exits from the other end of the other optical fiber cable. The aforementioned information processing device is The transmitting device includes an emission control unit that emits light, The aforementioned master receiver unit includes a received light change receiving unit that receives changes in the intensity of light received over time, A fault location derivation unit derives the fault location that occurred in the pair of optical fiber cables based on the time of change in the intensity of the received light received by the received light change receiving unit and the propagation speed of light in the pair of optical fiber cables, It has, The output control unit causes the transmitting device to emit pulsed light. Based on the first time from when the transmitting device emits the pulsed light until the master receiving device receives the pulsed light, and the pre-determined distance between the master and child optical fibers, which is the distance from one end to the other of the pair of optical fibers, the propagation speed of the light in the pair of optical fibers is determined based on the following equation (1): The propagation speed = the distance between parent and child / (the first time / 2) Equation (1) The emission control unit emits light of a certain intensity to the transmitting device. The aforementioned base station has a first clock, The aforementioned localization device has a second clock, The first clock and the second clock are synchronized. The aforementioned branching device branches light, The aforementioned location sub-unit has a sub-unit receiving device that receives the branched light, The accident location derivation unit is, The time at which the master receiver detects light of an intensity weaker than a predetermined second intensity is defined as the third time. The time at which the sub-unit receiving device detects light of an intensity weaker than a predetermined third intensity is defined as the fourth time. The distance of the accident site from the ground control unit is derived based on the following equation (3): Distance from the aforementioned location of the accident to the aforementioned location sensor = ((Distance between the base station and the sub-station) - (Third time - Fourth time) × Propagation speed) / 2 Formula (3) A localization system.

2. A location system for locating the site of a power cable failure, A pair of optical fiber cables installed parallel to the aforementioned power cable, The base station and The location tracking device, It has an information processing device, The aforementioned location master unit has a transmitting device that transmits light by injecting it into one end of one of the pair of optical fiber cables. The location sub-unit has a branching device that branches the light emitted from the other end of one of the optical fiber cables and directs it into one end of the other optical fiber cable of the pair of optical fiber cables. The aforementioned location master unit has a master unit receiving device that receives emitted light that enters one end of the other optical fiber cable and exits from the other end of the other optical fiber cable. The aforementioned information processing device is The transmitting device includes an emission control unit that emits light, The aforementioned master receiver unit includes a received light change receiving unit that receives changes in the intensity of light received over time, A fault location derivation unit derives the fault location that occurred in the pair of optical fiber cables based on the time of change in the intensity of the received light received by the received light change receiving unit and the propagation speed of light in the pair of optical fiber cables, It has, The output control unit causes the transmitting device to emit pulsed light. Based on the first time from when the transmitting device emits the pulsed light until the master receiving device receives the pulsed light, and the pre-determined distance between the master and child optical fibers, which is the distance from one end to the other of the pair of optical fibers, the propagation speed of the light in the pair of optical fibers is determined based on the following equation (1): The propagation speed = the distance between parent and child / (the first time / 2) Equation (1) The emission control unit emits light of a certain intensity to the transmitting device. The aforementioned base station has a first clock, The aforementioned localization device has a second clock, The first clock and the second clock are synchronized. The aforementioned branching device branches light, The aforementioned location sub-unit has a sub-unit receiving device that receives the branched light, The accident location derivation unit is, The time at which the master receiver detects light with an intensity stronger than a predetermined fourth intensity is defined as the fifth time. The time at which the sub-unit receiving device detects light with an intensity stronger than a predetermined fifth intensity is defined as the sixth time. The distance of the accident site from the ground control unit is derived based on the following equation (4): Distance from the aforementioned location of the accident to the aforementioned location sensor = ((Distance between the base station and the base station) - (5th time - 6th time) × propagation speed) / 2 Formula (4) A localization system.

3. The base station transmits a predetermined signal pattern to the base station and simultaneously resets the time of the first clock. The base station receives the predetermined signal pattern, splits the light, and emits it toward the base station, simultaneously resetting the second clock. The base station receives the predetermined signal pattern, detects the time difference between the time of reception and the time of transmission, detects that the time indicated by the second clock is behind the time indicated by the first clock by half the time difference, and synchronizes the first clock and the second clock. The positioning system according to claim 1 or claim 2.

4. The first clock and the second clock are synchronized based on the time of an atomic clock received from satellite radio waves. The positioning system according to claim 1 or claim 2.

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