Optical cable fault positioning method based on multi-parameter fusion detection device

Abstract

The invention discloses an optical cable fault positioning method based on a multi-parameter fusion detection device, and relates to the technical field of optical cables, and the multi-parameter fusion detection device used in the optical cable fault positioning method is internally provided with an optical time domain reflection module, a distributed vibration sensing module and a distributed optical fiber sensing temperature measurement module. Firstly, the optical time domain reflection module is gated to quickly determine the distance of a fault point along a cable, and then the distributed vibration sensing module is switched to determine an accurate target fault position where the fault point is located, and then candidate optical cables are quickly screened out; according to the method, the OTDR technology, the optical fiber vibration sensing technology and the optical fiber temperature measurement technology are fused, optical cable fault positioning can be rapidly completed on the premise that the optical cable is not damaged and the bearing service of the optical cable is not affected, and the optical cable fault positioning accuracy is improved. The method has good fault positioning accuracy, precision and timeliness.

Description

Technical Field

[0001] The present application relates to the field of optical cable technology, and in particular to an optical cable fault location method based on a multi-parameter fusion detection device. Background Art

[0002] At present, the rapid development of telecommunication technology has made optical fiber communication gradually popularized in all fields of society. It has advantages that other communication methods cannot match, such as large capacity, low loss, wide bandwidth, light weight, low price, anti-crosstalk, anti-interference, and convenient construction. The practicality of optical fiber communication is generally favored by builders. Cable communication has been gradually replaced by optical fiber communication, and it has been widely used in railway communication.

[0003] In the fiber optic communication scenario, it is very important to operate and maintain the optical cable. After discovering a fault in the optical cable, quickly repairing and splicing the optical cable can reduce the impact of the optical cable fault on the business. However, in actual application scenarios, optical cables are often installed underground or overhead, and there are usually a large number of optical cables installed and laid together. This complex installation environment makes it difficult to quickly identify which optical cable is the faulty one, which brings considerable difficulties to the fault location of the optical cable. The existing commonly used optical cable fault location methods are mainly the following, but they all have their own shortcomings:

[0004] (1) Use a red light pen to illuminate the faulty optical cable at the optical cable junction box, then remove the outer sheath of each optical cable and bend the inner core of the optical cable at the test point. If red light can be seen at the test point, it is determined that the optical cable currently removed and bent is the faulty optical cable. However, this method will cause irreversible damage to the optical cable and easily affect the services carried by the optical cable. In addition, this method is limited by the transmission distance of the red light and is only effective when the optical cable junction box is within a few thousand meters from the test point.

[0005] (2) Each optical cable is bent to a certain degree in turn to form a cable loss point, and the OTDR (Optical Time-Domain Reflectometer) technology is used to detect the faulty optical cable. When the artificially formed cable loss point is detected, it can be determined that the currently bent optical cable is the faulty optical cable. This method will also cause irreversible damage to the optical cable and easily affect the services carried by the optical cable, especially the ADSS optical cable has a metal reinforcement core, which cannot be restored after bending. In addition, the bend generally causes 1-3dB of attenuation to be detected by OTDR technology. In this process, other services will be interrupted or bit errors will occur.

[0006] (3) Using an optical cable survey instrument to identify optical cables using the optical interference method, this method can identify faulty optical cables without damaging them. However, this method often makes misjudgments in complex environments where there are many optical cables and the cables are in close contact, and its accuracy is low. Summary of the invention

[0007] In view of the above problems and technical requirements, this application proposes a method for locating optical cable faults based on a multi-parameter fusion detection device. The technical solution of this application is as follows:

[0008] An optical cable fault locating method based on a multi-parameter fusion detection device, the optical cable fault locating method comprising:

[0009] Connect one core of the optical cable to be tested to the optical port of a multi-parameter fusion detection device, the multi-parameter fusion detection device has built-in optical time domain reflection module, distributed vibration sensing module and distributed optical fiber sensing and temperature sensing module, and the optical time domain reflection module, distributed vibration sensing module and distributed optical fiber sensing and temperature sensing module are connected to the optical port of the multi-parameter fusion detection device via an optical gating switch;

[0010] Control the optical gating switch of the multi-parameter fusion detection device to gate the path between the optical time domain reflection module and the optical port, and use the optical time domain reflection module built into the multi-parameter fusion detection device to determine the length between the fault point of the optical cable to be tested and the multi-parameter fusion detection device;

[0011] Controlling the optical gating switch of the multi-parameter fusion detection device to select the path between the distributed vibration sensing module and the optical port, using the distributed vibration sensing module to determine the target fault position where the fault point of the optical cable to be tested is located according to the length between the fault point and the multi-parameter fusion detection device, applying vibration excitation directly acting on each optical cable in sequence when each optical cable at the target fault position is exposed, and using the built-in distributed vibration sensing module of the multi-parameter fusion detection device to screen out candidate optical cables;

[0012] The optical gating switch of the multi-parameter fusion detection device is controlled to select the path between the distributed optical fiber temperature sensing module and the optical port, the screened candidate optical cable is heated, and the optical cable to be tested is identified by using the distributed optical fiber temperature sensing module built into the multi-parameter fusion detection device.

[0013] The beneficial technical effects of this application are:

[0014] The present application discloses a method for locating an optical cable fault based on a multi-parameter fusion detection device. The multi-parameter fusion detection device used in the optical cable fault locating method has a built-in optical time domain reflection module, a distributed vibration sensing module and a distributed optical fiber sensing temperature measurement module. When the multi-parameter fusion detection device is used to perform the optical cable fault locating method, the optical time domain reflection module is first selected to quickly determine the distance of the fault point along the cable line, and then the distributed vibration sensing module is switched to determine the target fault position where the exact fault point is located, and then the candidate optical cables that may be the optical cables to be tested are quickly screened out. Finally, the distributed optical fiber sensing temperature measurement module is switched to use a temperature judgment method to further judge and identify the candidate optical cables to determine the optical cables to be tested. The method integrates OTDR technology, optical fiber vibration sensing technology, and optical fiber temperature measurement technology to quickly complete the optical cable fault location without damaging the optical cable and affecting the existing services carried by the optical cable, and has good fault location accuracy, precision and timeliness.

[0015] This optical cable fault locating method uses a distributed vibration sensing module combined with an optical time domain reflection module to obtain the length between the fault point and the multi-parameter fusion detection device, and can obtain a more accurate target fault position where the fault point in the optical cable to be tested is located. It can improve the positioning accuracy of fault points such as buried optical cables and overhead optical cables to ±1m.

[0016] When making temperature judgments, the optical cable fault location method not only considers the temperature increase process but also the temperature decrease process, and increases the temperature change trend through the data processing method of the exponential relationship in the judgment process, which can make the data changes caused by the temperature change more obvious. It can not only reduce the requirements for the temperature increase range of the heating device, but also reduce the interference of noise on the signal and improve the judgment accuracy.

[0017] The optical cable fault location method also provides an analysis method for reducing the influence of connector reflected light, which can not only improve the accuracy and precision of fault location, but also reduce the influence of optical port end face reflection, so that it can be implemented using an ordinary UPC interface, reducing the difficulty of application.

[0018] The optical cable fault location method also provides a new heating device, which adopts the method of adding insulation cotton on both sides and heating on one side, which can not only improve the heating efficiency, but also effectively avoid the harm to the operation and maintenance personnel caused by high temperature. Low power consumption and controllable temperature make the present invention have a longer battery life in actual use.

[0019] The multi-parameter fusion detection device in the present application also has a wireless communication function, which is convenient for remote operation and data transmission, so that a single person can complete the optical cable maintenance work, which can greatly reduce the human resources required for optical cable operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a structural schematic diagram of a multi-parameter fusion detection device according to an embodiment of the present application.

[0021] Figure 2 It is a structural schematic diagram and application schematic diagram of a multi-parameter fusion detection device of another embodiment of the present application.

[0022] Figure 3 It is a method flow chart of an optical cable fault locating method according to an embodiment of the present application.

[0023] Figure 4 It is a flow chart of a method for determining a target fault location of a fault point in one embodiment of the present application.

[0024] Figure 5 It is a flow chart of a method for detecting whether the temperature curve of the entire optical cable meets the predetermined curve characteristics in one embodiment of the present application.

[0025] Figure 6 It is a schematic structural diagram of the heating surface of the heating device in one embodiment of the present application.

[0026] Figure 7 It is a schematic structural diagram of the other side surface of the heating device in one embodiment of the present application. DETAILED DESCRIPTION

[0027] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0028] This application discloses a method for locating optical cable faults based on a multi-parameter fusion detection device. The method for locating optical cable faults requires the use of a multi-parameter fusion detection device designed in this application. Please refer to Figure 1 The circuit structure diagram of the multi-parameter fusion detection device shown in the figure, the multi-parameter fusion detection device provides an optical port for connecting an optical cable, the multi-parameter fusion detection device has an optical time domain reflection module, a distributed vibration sensing module and a distributed optical fiber sensing temperature sensing module built in, the optical time domain reflection module, the distributed vibration sensing module and the distributed optical fiber sensing temperature sensing module are connected to the optical port of the multi-parameter fusion detection device via an optical gating switch. The optical gating switch can switch the passage between one of the optical time domain reflection module, the distributed vibration sensing module and the distributed optical fiber sensing temperature sensing module and the optical port.

[0029] The basic principle of the optical time domain reflectometer module is to use the transmission characteristics of light in the optical fiber, and to analyze the performance of the optical fiber by measuring the reflected signal when the light pulse propagates in the optical fiber. The distributed vibration sensing module uses the optical fiber as the sensing medium, and detects and locates vibration events along the length of the optical fiber through the scattering effect (mainly Rayleigh scattering) in the optical fiber. The distributed optical fiber temperature sensing module uses the optical time domain reflectometer (OTDR) technology and the Raman scattering effect to measure the temperature changes distributed along the optical fiber. The optical time domain reflectometer module, the distributed vibration sensing module and the distributed optical fiber temperature sensing module can all be implemented with existing integrated modules, and their specific structures can refer to the existing finished product modules, and this application will not go into details.

[0030] Since the optical time domain reflection module, the distributed vibration sensing module and the distributed fiber optic temperature sensing module are very sensitive to reflected light, in one embodiment, the optical time domain reflection module, the distributed vibration sensing module and the distributed fiber optic temperature sensing module are connected to the optical selection switch by fiber optic fusion splicing respectively. Compared with the conventional flange connection method, this approach can effectively reduce joint loss and joint reflected light.

[0031] In actual application, the multi-parameter fusion detection device also includes a main control module, which is also built into the multi-parameter fusion detection device. The main control module is respectively connected to the optical time domain reflection module, the distributed vibration sensing module and the distributed optical fiber sensing temperature sensing module, and the main control module is also connected to and controls the optical gating switch. In addition to including a microcontroller for performing control and data processing functions, the main control module also includes necessary data storage, analog-to-digital conversion circuits, digital-to-analog conversion circuits, and power management circuits, etc., which will not be described in detail in this application.

[0032] The multi-parameter fusion detection device is a portable device, which can be easily carried to the optical cable working site for use.

[0033] In one embodiment, the multi-parameter fusion detection device further includes a human-computer interaction module connected to the main control module, which facilitates on-site display of detection data and related control settings. The human-computer interaction module can be implemented as a touch screen, or as a display screen and touch buttons, etc. The operator can directly operate and input a gating instruction through the human-computer interaction module of the multi-parameter fusion detection device, and the multi-parameter fusion detection device controls the optical gating switch to switch the selected path according to the received gating instruction. In addition, the multi-parameter fusion detection device can also use the human-computer interaction module to display various detection data obtained during the detection process. Figure 1 The human-computer interaction module is not shown.

[0034] In another embodiment, the multi-parameter fusion detection device further includes a wireless communication module connected to the main control module. Figure 2, the multi-parameter fusion detection device establishes wireless communication with the smart terminal 1 through the built-in wireless communication module. The operator can use the wireless communication method to remotely send a gating instruction to the multi-parameter fusion detection device through the smart terminal. Similarly, the multi-parameter fusion detection device controls the optical gating switch to switch the selected path according to the received gating instruction. In addition, the multi-parameter fusion detection device can also use wireless communication to send various detection data obtained during the detection process to the smart terminal, so that the operator can remotely receive and display various detection data obtained by the multi-parameter fusion detection device on the smart terminal. Wireless communication can be established between the multi-parameter fusion detection device and the smart terminal by using wifi or Bluetooth, or by establishing wireless communication via a server. Figure 2 Take connecting via a server as an example.

[0035] Based on the multi-parameter fusion detection device disclosed in this application, please refer to Figure 3 As shown in the flowchart, the optical cable fault locating method comprises the following steps:

[0036] Step 1: Connect one core of the optical cable to be tested to the optical port of the multi-parameter fusion detection device.

[0037] Step 2, controlling the optical gating switch of the multi-parameter fusion detection device to select the path between the optical time domain reflection module and the optical port.

[0038] Step 3: Use the built-in optical time domain reflectometry module of the multi-parameter fusion detection device to determine the length L1 between the fault point of the optical cable to be tested and the multi-parameter fusion detection device.

[0039] The optical time domain reflection module emits a pulsed optical signal when working, and the pulsed optical signal enters the optical cable to be tested through the optical port. When the pulsed optical signal propagates in the optical cable to be tested, the fault point in the optical cable to be tested will cause part of the light to be reflected back and return to the optical time domain reflection module through the optical port, causing the optical time domain reflection module to obtain the optical fiber signal acquisition value through the optical port. The optical time domain reflection module processes and analyzes the optical fiber signal acquisition value to determine the relevant information of the fault point of the optical cable to be tested: by measuring the time it takes for the reflected signal to return to the optical time domain reflection module, the length between the fault point in the optical cable to be tested and the multi-parameter fusion detection device can be determined. The present application ignores the transmission path in the multi-parameter fusion detection device within the error range, and it can be considered that the length of the reflected signal returning to the optical port of the multi-parameter fusion detection device is the length returned to the optical time domain reflection module. The specific working principle of the optical time domain reflection module can refer to the existing working principle, which will not be repeated here.

[0040] Step 4, controlling the optical gating switch of the multi-parameter fusion detection device to select the path between the distributed vibration sensing module and the optical port.

[0041] Step 5: Determine the target fault position of the fault point of the optical cable to be tested by using the distributed vibration sensing module in combination with the length L1 between the fault point and the multi-parameter fusion detection device.

[0042] In one embodiment, the method for determining the target fault location where the fault point is located includes the following steps, please refer to Figure 4 Flowchart:

[0043] First, the estimated position of the fault point of the optical cable to be tested is obtained according to the laying direction of the optical cable to be tested and the length L1 between the fault point and the multi-parameter fusion detection device. This step is specifically an existing practice, which usually equates the direction of the optical cable to be tested to a broken line segment, and then takes the position along the broken line segment and the multi-parameter fusion detection device with a total length of L1 as the estimated position of the fault point. However, in reality, the optical cable is not laid in a strictly straight line direction, and there will inevitably be bends. Therefore, although the estimated position of the fault point obtained by this method can roughly indicate the area where the fault point is located, the accuracy of the estimated position is not enough.

[0044] The existing practice is to directly use the estimated location of the fault point as the target fault location of the fault point, but as mentioned above, the accuracy and precision of such results are low. Especially in the case of buried optical cables, it is necessary to dig out the ground according to the target fault location of the fault point. The deviation of the target fault location will bring greater maintenance difficulty and time-consuming.

[0045] Therefore, the present application further combines a distributed vibration sensing module to obtain a target fault location with higher accuracy and precision. After obtaining the estimated location of the fault point and switching to the gated distributed vibration sensing module. Apply vibration excitation at the estimated location of the fault point of the optical cable to be tested, and use the multi-parameter fusion detection device to determine the length L2 between the location where the vibration excitation is applied and the multi-parameter fusion detection device through the built-in distributed vibration sensing module.

[0046] When this step applies vibration excitation at the estimated position of the fault point of the optical cable to be tested, it does not necessarily act directly on the optical cable to be tested. The vibration excitation may be indirectly applied to the optical cable to be tested via vibration transfer. For example, in the underground optical cable scenario, all optical cables are still buried underground at this time, and it is impossible to directly apply vibration excitation to the optical cable. Therefore, this step is implemented by applying vibration excitation on the ground at the estimated position of the fault point of the optical cable to be tested. The vibration excitation applied on the ground will act on the buried optical cable below. No matter how the vibration excitation is applied, the vibration excitation will indirectly act on the optical cable to be tested. For another example, in the scenario of high-altitude optical cables, several optical cables may be bundled and fixed together. At this time, the vibration excitation can be applied to the bundling structure, and then indirectly transferred to the optical cable to be tested.

[0047] The distributed vibration sensing module will also emit a pulse light signal when working. The pulse light signal enters the optical cable to be tested through the optical port. When the pulse light signal propagates in the optical cable to be tested, the vibration in the optical cable to be tested will cause the stress of the optical cable to be tested to change, thereby affecting the propagation characteristics of the light in the optical cable to be tested, so that the scattered light signal transmitted back in the optical cable to be tested changes and returns to the distributed vibration sensing module through the optical port. The distributed vibration sensing module analyzes the phase, intensity and frequency changes of the acquired optical fiber signal acquisition value, and can detect vibration events occurring along the length of the optical cable to be tested, and accurately locate the position of vibration excitation, thereby determining the length L2 between the position where the vibration excitation is applied and the multi-parameter fusion detection device. The specific working principle of the distributed vibration sensing module can refer to the existing working principle, and this application will not repeat it.

[0048] Ideally, if the estimated position of the fault point of the optical cable to be tested is the exact position of the fault point, then when vibration excitation is applied at the estimated position of the fault point, the position of the optical cable to be tested that is subjected to vibration excitation should also be the position of the fault point, and L2 should be equal to L1 at this time. However, as mentioned above, since the estimated position of the fault point is often not the exact position of the fault point, L2 is usually not equal to L1. The position where the vibration excitation is applied continues to be adjusted and L2 is determined again until the error between the length L2 between the position where the vibration excitation is applied determined by the distributed vibration sensing module and the multi-parameter fusion detection device and the length L1 between the fault point of the optical cable to be tested and the multi-parameter fusion detection device is within the error range, that is, when L2 and L1 are substantially equal, the position where the vibration excitation is currently applied is taken as the target fault position where the fault point of the optical cable to be tested is located.

[0049] Step 6, after the target fault location where the fault point is accurately determined in step 5, each optical cable at the target fault location can be exposed. For example, in the case of buried optical cables, each optical cable at the target fault location is dug out from the ground to be exposed. For example, in the case of high-altitude installation, each optical cable at the target fault location is unbundled to be exposed. When each optical cable is exposed, vibration excitation directly acting on a single optical cable can be applied.

[0050] In the current optical cable operation and maintenance scenario, the installation environment of the optical cable is usually more complicated, and a large number of optical cables are closely contacted and installed together. Therefore, there are usually multiple optical cables closely contacted and installed together at the target fault location, and it is necessary to further distinguish which one is the optical cable to be tested. The approach of this application is to use the distributed vibration sensing module built into the multi-parameter fusion detection device to screen out candidate optical cables while applying vibration excitation directly to each optical cable in turn.

[0051] As described above, the distributed vibration sensing module connected to the optical cable to be tested can locate the position of the optical cable to be tested that is subjected to vibration excitation when working. Therefore, in an ideal state, when a vibration excitation is applied directly to the optical cable to be tested, the distributed vibration sensing module can detect the vibration excitation, and when a vibration excitation is applied directly to other optical cables, the distributed vibration sensing module will not detect the vibration excitation. In theory, the optical cables to be tested can be directly screened out through this distinction.

[0052] However, due to the close contact between the optical cables, vibrations will be transmitted between the optical cables, causing crosstalk and thus misjudgment. For example, when a vibration excitation is applied to other optical cables, this vibration may also be transmitted to the optical cable to be tested, causing the distributed vibration sensing module to detect the vibration excitation. The misjudgment caused by this crosstalk will cause the selected candidate optical cables to include several other optical cables in addition to the optical cable to be tested, and the optical cable to be tested cannot be directly and accurately identified. Although the accuracy of identifying the optical cable to be tested by vibration judgment is not high, the timeliness of vibration judgment is faster. Therefore, the present application uses vibration judgment for preliminary screening, leaving only the candidate optical cables for subsequent identification. Optical cables other than the candidate optical cables are definitely not the optical cables to be tested, and they will no longer enter the subsequent identification, which can improve the efficiency of fault location while ensuring the accuracy of fault location.

[0053] Step 7, control the optical gating switch of the multi-parameter fusion detection device to select the path between the distributed optical fiber sensor temperature measurement module and the optical port.

[0054] Step 8: Heat the selected candidate optical cables and use the distributed optical fiber sensing temperature measurement module built into the multi-parameter fusion detection device to identify the optical cable to be tested.

[0055] When the distributed optical fiber temperature sensor module is working, it will also emit a pulsed optical signal, which will enter the optical cable to be tested through the optical port and will be reflected back through the optical port to the distributed optical fiber temperature sensor module. The optical fiber temperature sensor module uses optical time domain reflectometry (OTDR) technology and Raman scattering effect. By detecting the return time of the acquired optical fiber signal acquisition value, it can determine the temperature signal distributed at various locations of the optical cable to be tested, that is, obtain the temperature curve of the entire optical cable. The temperature curve of the entire optical cable indicates the temperature distribution of different optical cable positions of the optical cable to be tested.

[0056] This application provides two different heating identification mechanisms, which are introduced as follows:

[0057] 1. Sequential heating method

[0058] (1) Each candidate optical cable is traversed in turn, and each candidate optical cable is heated each time, and a multi-parameter fusion detection device is used to measure the temperature curve of the entire optical cable through the built-in distributed optical fiber sensor temperature measurement module.

[0059] (2) When it is determined that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristics, it is determined that the candidate optical cable currently traversed is not the optical cable to be tested, and the next candidate optical cable is traversed in sequence.

[0060] (3) When it is determined that the measured temperature curve of the entire optical cable meets the predetermined curve characteristics, the candidate optical cable currently traversed is determined to be the optical cable to be tested, the traversal is terminated, and the faulty optical cable to be tested and the target fault location where the fault point is located are located, so that fault detection and maintenance can be carried out quickly.

[0061] 2. Binary heating method

[0062] (1) All the remaining candidate optical cables are divided into two groups using the binary method. Several candidate optical cables in one group are heated simultaneously, and the temperature curve of the entire optical cable is measured by a multi-parameter fusion detection device through a built-in distributed optical fiber sensor temperature measurement module.

[0063] (2) When it is determined that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristics, it is determined that the optical cable to be tested is not in the current group but in another group, then all candidate optical cables in the current group are screened out, all candidate optical cables in the other group are retained, and the step of using the binary method to divide all the remaining candidate optical cables into two groups is continued until the optical cable to be tested is determined. The other group can also be further determined and confirmed before screening.

[0064] (3) When it is determined that the measured temperature curve of the entire optical cable meets the predetermined curve characteristics, it is determined that the optical cable to be tested is in the current group, all candidate optical cables in the other group are screened out, all candidate optical cables in the current group are retained, and the step of using the binary method to divide all the remaining candidate optical cables into two groups is continued until the optical cable to be tested is determined to be obtained.

[0065] The sequential traversal heating method is simple and easy to operate. Since the traversal order is relatively random, it is possible to quickly identify the optical cable to be tested, or it may be necessary to traverse all candidate optical cables before identifying the optical cable to be tested. Especially when the number of candidate optical cables is large, heating each cable may take a long time. The binary heating method requires multiple rounds of heating screening to identify the optical cable to be tested, but it can have a faster screening effect when the number of candidate optical cables is large. In actual operation and maintenance, the heating mechanism to be used can be selected according to needs, or the heating mechanism to be used can be determined according to the number of candidate optical cables. For example, when the number of candidate optical cables reaches the quantity threshold, the binary heating method is used to quickly screen out some candidate optical cables. When the number of candidate optical cables is less than the quantity threshold, the sequential traversal heating method is used to traverse each optical cable one by one. In practice, these two methods can also be used in combination. For example, the binary heating method is used when the number of initial candidate optical cables is small. After several rounds of screening, the number of candidate optical cables decreases, and the sequential traversal heating method is used.

[0066] Regardless of whether the sequential traversal heating method or the binary heating method is used, during the heating process, it is necessary to collect the temperature curve of the entire optical cable and determine whether the measured temperature curve of the entire optical cable meets the predetermined curve characteristics. In one embodiment, in order to improve the recognition accuracy, not only the temperature rising process is collected and detected, but also the temperature falling process is collected and detected, including the following steps, please refer to Figure 5 :

[0067] 1. Use the multi-parameter fusion detection device to measure the first temperature curve of the entire optical cable through the built-in distributed optical fiber sensor temperature measurement module during the heating process of the candidate optical cable. The heating time and heating temperature of the candidate optical cable when heated by the heating device are set according to actual needs. Usually, the thickness of the optical cable needs to be considered for adjustment. Generally, the heating device is required to increase the temperature by more than 20°C, which can increase the temperature of the optical cable by more than 7°C.

[0068] 2. Check whether the first temperature curve of the entire optical cable meets the temperature rise characteristics. Including:

[0069] (1) The first temperature curve of the entire optical cable detected when the candidate optical cable starts to be heated and reaches the predetermined heating time is subtracted from the reference temperature curve of the entire optical cable when the heating starts to be obtained. The temperature rise curve of the entire optical cable indicates the temperature rise values ​​at different positions of the optical cable.

[0070] (2) An exponential function is used to numerically amplify the temperature rise value of the temperature rise curve of the entire optical cable to obtain an amplified temperature rise curve of the entire optical cable. The amplified temperature rise curve of the entire optical cable can more clearly show the rapid temperature rise.

[0071] (3) When the peak value of the temperature rise value in the amplified temperature rise curve of the entire optical cable reaches the first amplitude threshold, it means that the optical cable meets the corresponding temperature rise requirement, such as the temperature rise requirement of 7°C. At this time, it can be determined that the first temperature curve of the entire optical cable meets the temperature rise characteristics. Otherwise, it is determined that the first temperature curve of the entire optical cable does not meet the temperature rise characteristics. The first amplitude threshold is customized according to the heating situation and the value amplification method.

[0072] When it is determined that the first temperature curve of the entire optical cable meets the temperature rise characteristics, the optical cable position corresponding to the peak value of the temperature rise value in the amplified temperature rise curve of the entire optical cable can be further determined as the reference optical cable position.

[0073] 2. When the first temperature curve of the entire optical cable does not satisfy the temperature rise characteristic, it is determined that the measured temperature curve of the entire optical cable does not satisfy the predetermined curve characteristic.

[0074] 3. When the first temperature curve of the entire optical cable meets the temperature rise characteristics, the second temperature curve of the entire optical cable is measured by using the multi-parameter fusion detection device through the built-in distributed optical fiber sensor temperature measurement module during the cooling process of stopping heating.

[0075] 4. Check whether the second temperature curve of the entire optical cable meets the cooling characteristics. Including:

[0076] (4) The temperature drop curve of the entire optical cable is obtained by subtracting the second temperature curve of the entire optical cable detected when the heating of the candidate optical cable is stopped and the predetermined temperature drop time is reached from the reference temperature curve of the entire optical cable when the heating is stopped. The temperature drop curve of the entire optical cable indicates the temperature drop value at different optical cable positions.

[0077] (5) The temperature reduction value of the temperature drop curve of the entire optical cable is numerically amplified by using an exponential function to obtain an amplified temperature drop curve of the entire optical cable. The amplified temperature drop curve of the entire optical cable can more clearly show the rapid temperature drop. The second amplitude threshold is customized according to the numerical amplification method.

[0078] (6) When the temperature reduction value of the amplified temperature reduction curve of the entire optical cable at the reference optical cable position determined above reaches the second amplitude threshold, it is determined that the second temperature curve of the entire optical cable meets the temperature reduction characteristic; otherwise, it is determined that the second temperature curve of the entire optical cable does not meet the temperature reduction characteristic.

[0079] 5. When the second temperature curve of the entire optical cable does not meet the temperature reduction characteristics, it is determined that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristics.

[0080] 6. When the second temperature curve of the entire optical cable meets the temperature reduction characteristics, it is determined that the measured temperature curve of the entire optical cable meets the predetermined curve characteristics.

[0081] In order to facilitate the heating of the optical cable and meet the need to heat multiple optical cables at the same time, the present application also provides a new heating device in another embodiment, please refer to Figure 6 and Figure 7 As shown in the structural diagram, the heating device includes a foldable heating plate, a temperature controller and a power supply. The power supply supplies power to the temperature controller. The heating plate is made of thermally conductive insulating material and has a built-in resistance coil 2. The temperature controller is connected to the resistance coil 2 in the heating plate and performs heating control.

[0082] The heating plate is provided with matching openable and closable components 3 on both sides of the heating surface along the closing direction, and the other side of the heating plate is covered with soft thermal insulation cotton 4 for heat insulation. The heating plate has a certain size to meet the needs of heating multiple optical cables at the same time, and the soft thermal insulation cotton 4 laid on the back of the heating plate can avoid the impact on other optical cables during the heating process of some optical cables, reduce the error caused by crosstalk during the heating process, and improve the recognition accuracy. The heating plate can be opened to form an expanded state or closed to form a closed state, and the openable and closable component 3 can be a button, etc., for example, to fix the closed state of the heating plate.

[0083] The closable component 3 of the heating sheet is opened to form an extended state, the heating surface of the heating sheet contacts the candidate optical cable, the extended state heating sheet is wrapped around the outside of the candidate optical cable, and then closed along the closing direction and fixed using the closable component 3, the closed state of the heating sheet is maintained and the wrapped candidate optical cable is heated. In practical applications, the heating sheet can be designed as a double-sided structure connected by a connecting strip, such as Figure 6 and Figure 7 Take this as an example, Figure 6 It is a schematic diagram of the unfolded structure of the heating surface of the heating plate, such as Figure 7 It is a schematic diagram of the unfolded structure of the other side surface of the heating plate. This structure is convenient for folding and closing, and also convenient for wrapping multiple optical cables inside the heating plate so that they can be laid as flat as possible on the heating surface of the heating plate for direct heating.

[0084] The accuracy of identifying the optical cable to be tested by temperature judgment using a distributed optical fiber sensor temperature module is high, but the timeliness of the judgment is not as good as the vibration judgment. If the temperature of each optical cable is directly judged in step 6, the efficiency is low. The present application first uses vibration judgment to screen out candidate optical cables and then further performs temperature judgment, which can take into account both the timeliness and accuracy of the judgment and has a better fault location effect.

[0085] This application utilizes the three different modules built into the multi-parameter fusion detection device to perform fault location, and the fault location can be finally achieved by switching and selecting different modules at different stages of identification. In addition, it can be seen from the identification process described above that in the fault identification process, it is often necessary to apply vibration excitation at a remote location of the multi-parameter fusion detection device. At this time, the remote communication function of the multi-parameter fusion detection device of this application can ensure that even if there is only one operation and maintenance personnel, the operation and maintenance personnel can apply vibration excitation and perform heating operations at the fault point area after completing the connection between the multi-parameter fusion detection device and the optical cable to be tested, and operate the multi-parameter fusion detection device through remote control to switch the selected modules and obtain relevant data, which simplifies the difficulty of operation and maintenance.

[0086] In addition, when each of the three modules is working, it is necessary to analyze the optical fiber signal acquisition value obtained through the optical port to obtain the corresponding result. However, the obtained optical fiber signal acquisition value inevitably still has some interference signals, which will affect the results of data analysis, and then affect the accuracy and precision of fault location. Therefore, in another embodiment, in order to further improve the accuracy and precision of optical cable fault location, when the multi-parameter fusion detection device is connected to the optical cable to be tested, any one of the optical time domain reflection module, distributed vibration sensing module and distributed optical fiber sensing temperature sensing module obtains the optical fiber signal acquisition value through the optical port. After the optical fiber signal acquisition value is obtained, the signal characteristics of the optical fiber signal acquisition value are first extracted. The optical fiber signal acquisition value shows the reflection point and intensity in the optical fiber, especially the reflection at the optical port joint. The extracted signal characteristics include the intensity and position of the reflected light. Then determine the interference signal in the interference signal database that matches the signal characteristics of the optical fiber signal acquisition value, and the signal matching can use KNN or other pattern matching algorithms. The interference signal database is pre-simulated and established, and the interference signal database includes the signal characteristics of interference signals under various optical port joint conditions, and the signal characteristics here also include the intensity and position of the reflected light. After the interference signal is matched and determined, the interference signal can be removed from the optical fiber signal acquisition value to obtain the target sensing signal, and then subsequent data processing is performed on the target sensing signal to reduce the interference caused by the optical port connector.

[0087] The above approach can reduce the influence of the reflection at the optical port end face, so that the optical port of the multi-parameter fusion detection device can use an ordinary UPC interface without using a special APC pigtail, thereby reducing the difficulty of application.

[0088] The above is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.

Claims

1. A method for locating optical cable faults based on a multi-parameter fusion detection device, characterized in that: The optical cable fault locating method comprises: Connect one core of the optical cable to be tested to the optical port of a multi-parameter fusion detection device, wherein the multi-parameter fusion detection device has a built-in optical time domain reflection module, a distributed vibration sensing module, and a distributed optical fiber sensing and temperature measurement module, and the optical time domain reflection module, the distributed vibration sensing module, and the distributed optical fiber sensing and temperature measurement module are connected to the optical port of the multi-parameter fusion detection device via an optical gating switch; Controlling the optical gating switch of the multi-parameter fusion detection device to gate the path between the optical time domain reflection module and the optical port, and using the optical time domain reflection module built into the multi-parameter fusion detection device to determine the length between the fault point of the optical cable to be tested and the multi-parameter fusion detection device; Controlling the optical gating switch of the multi-parameter fusion detection device to select the path between the distributed vibration sensing module and the optical port, using the distributed vibration sensing module to determine the target fault position where the fault point of the optical cable to be tested is located according to the length between the fault point and the multi-parameter fusion detection device, applying vibration excitation directly acting on each optical cable in sequence when each optical cable at the target fault position is exposed, and using the built-in distributed vibration sensing module of the multi-parameter fusion detection device to screen out candidate optical cables; The optical gating switch of the multi-parameter fusion detection device is controlled to select the path between the distributed optical fiber sensing temperature sensing module and the optical port, the screened candidate optical cable is heated, and the optical cable to be tested is identified by using the distributed optical fiber sensing temperature sensing module built into the multi-parameter fusion detection device.

2. The optical cable fault locating method according to claim 1, characterized in that: The step of heating the selected candidate optical cables and identifying the optical cables to be tested by using the distributed optical fiber sensing temperature measurement module built into the multi-parameter fusion detection device comprises: Traversing each candidate optical cable in turn, heating each traversed candidate optical cable each time and using the multi-parameter fusion detection device to measure the temperature curve of the entire optical cable through the built-in distributed optical fiber sensing temperature measurement module; When it is determined that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristics, it is determined that the candidate optical cable currently traversed is not the optical cable to be tested, and the next candidate optical cable is traversed in sequence; When it is determined that the measured temperature curve of the entire optical cable meets the predetermined curve characteristics, the candidate optical cable currently traversed is determined to be the optical cable to be tested.

3. The optical cable fault locating method according to claim 1, characterized in that: The step of heating the selected candidate optical cables and identifying the optical cables to be tested by using the distributed optical fiber sensing temperature measurement module built into the multi-parameter fusion detection device comprises: Divide all the remaining candidate optical cables into two groups by using a binary method, heat several candidate optical cables in one group at the same time, and use the multi-parameter fusion detection device to measure the temperature curve of the entire optical cable line through the built-in distributed optical fiber sensor temperature measurement module; When it is determined that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristics, all candidate optical cables in the current group are screened out, all candidate optical cables in another group are retained, and the step of dividing all the remaining candidate optical cables into two groups by using the binary method is continued until the optical cable to be tested is determined to be obtained; When it is determined that the measured temperature curve of the entire optical cable meets the predetermined curve characteristics, all candidate optical cables in the other group are screened out, all candidate optical cables in the current group are retained, and the step of using the binary method to divide all the remaining candidate optical cables into two groups is continued until the optical cable to be tested is determined to be obtained.

4. The optical cable fault locating method according to claim 2 or 3, characterized in that: The method of using the multi-parameter fusion detection device to measure the temperature curve of the entire optical cable through the built-in distributed optical fiber sensing temperature measurement module includes: Using the multi-parameter fusion detection device to measure the first temperature curve of the entire optical cable line through the built-in distributed optical fiber sensor temperature measurement module during the heating process of the candidate optical cable; When the first temperature curve of the entire optical cable does not meet the temperature rise characteristic, determining that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristic; When the first temperature curve of the entire optical cable meets the temperature rise characteristic, the second temperature curve of the entire optical cable is measured by using the multi-parameter fusion detection device through the built-in distributed optical fiber sensing temperature measurement module during the cooling process of stopping heating; When the second temperature curve of the entire optical cable does not meet the temperature reduction characteristic, determining that the measured temperature curve of the entire optical cable does not meet the predetermined curve characteristic; When the second temperature curve of the entire optical cable meets the temperature reduction characteristic, it is determined that the measured temperature curve of the entire optical cable meets the predetermined curve characteristic.

5. The optical cable fault locating method according to claim 4, characterized in that: Detecting whether the first temperature curve of the entire optical cable meets the temperature rise characteristic includes: The first temperature curve of the entire optical cable detected when the candidate optical cable starts to be heated and reaches a predetermined heating time is subtracted from the reference temperature curve of the entire optical cable when heating starts to obtain a temperature rise curve of the entire optical cable, wherein the temperature rise curve of the entire optical cable indicates the temperature rise values ​​at different positions of the optical cable; The temperature rise value of the temperature rise curve of the entire optical cable is numerically amplified by using an exponential function to obtain an amplified temperature rise curve of the entire optical cable; When the peak value of the temperature rise value in the amplified temperature rise curve of the entire optical cable reaches the first amplitude threshold, it is determined that the first temperature curve of the entire optical cable meets the temperature rise characteristic, otherwise it is determined that the first temperature curve of the entire optical cable does not meet the temperature rise characteristic.

6. The optical cable fault locating method according to claim 5, characterized in that: Detecting whether the second temperature curve of the entire optical cable meets the cooling characteristic includes: The temperature drop curve of the entire optical cable is obtained by subtracting the reference temperature curve of the entire optical cable when the heating is stopped from the second temperature curve of the entire optical cable detected when the heating of the candidate optical cable is stopped and the predetermined temperature drop time is reached, and the temperature drop curve of the entire optical cable indicates the temperature drop values ​​at different optical cable positions; An exponential function is used to numerically amplify the temperature reduction value of the optical cable full-line temperature reduction curve to obtain an amplified optical cable full-line temperature reduction curve; When the temperature reduction value of the amplified temperature reduction curve of the entire optical cable at the reference optical cable position reaches the second amplitude threshold, it is determined that the second temperature curve of the entire optical cable meets the temperature reduction feature; otherwise, it is determined that the second temperature curve of the entire optical cable does not meet the temperature reduction feature; The reference optical cable position is the optical cable position corresponding to the peak value of the temperature rise value in the amplified temperature rise curve of the entire optical cable line.

7. The optical cable fault locating method according to claim 1, characterized in that: The method of determining the target fault position where the fault point of the optical cable to be tested is located by using the distributed vibration sensing module in combination with the length between the fault point and the multi-parameter fusion detection device comprises: Obtaining an estimated position of the fault point of the optical cable to be tested according to the length between the fault point and the multi-parameter fusion detection device; Applying vibration excitation at the estimated position of the fault point of the optical cable to be tested, and using the multi-parameter fusion detection device to determine the length between the position where the vibration excitation is applied and the multi-parameter fusion detection device through a built-in distributed vibration sensing module; The position where vibration excitation is applied is adjusted until the error between the length between the position where vibration excitation is applied determined by the distributed vibration sensing module and the multi-parameter fusion detection device and the length between the fault point of the optical cable to be tested and the multi-parameter fusion detection device is within an error range, and the current position where vibration excitation is applied is taken as the target fault position where the fault point of the optical cable to be tested is located.

8. The optical cable fault locating method according to claim 1, characterized in that: The optical time domain reflection module, the distributed vibration sensing module and the distributed optical fiber sensing temperature measurement module are connected to the optical gating switch by optical fiber fusion splicing respectively; the optical port of the multi-parameter fusion detection device adopts a UPC interface, and the optical cable fault locating method also includes: When the multi-parameter fusion detection device is connected to the optical cable to be tested, after obtaining the optical fiber signal acquisition value through the optical port, any one of the optical time domain reflection module, the distributed vibration sensing module and the distributed optical fiber sensing and temperature measurement module extracts the signal characteristics of the optical fiber signal acquisition value, and determines the interference signal matching the signal characteristics of the optical fiber signal acquisition value in the interference signal database, filters out the interference signal from the optical fiber signal acquisition value to obtain the target sensing signal, and performs data processing on the target sensing signal; wherein, the interference signal database includes interference signals generated by multiple different optical port reflections and corresponding signal characteristics.

9. The optical cable fault locating method according to claim 1, characterized in that: Heating the selected candidate optical cables includes: The candidate optical cable is heated by a heating device, wherein the heating device comprises a closable heating plate, a temperature controller and a power supply, wherein the power supply supplies power to the temperature controller, the heating plate is made of a heat-conducting insulating material and has a built-in resistance coil, and the temperature controller is connected to the resistance coil in the heating plate and performs heating control; the heating plate is provided with matching closable components on both sides of the heating surface along the closing direction, and the other side of the heating plate is covered with soft thermal insulation cotton for heat insulation; The openable and closable component of the heating sheet is opened to form an expanded state, the heating surface of the heating sheet contacts the candidate optical cable, the expanded heating sheet is wrapped around the outside of the candidate optical cable, and then closed along the closing direction and fixed with the openable and closable component to maintain the closed state of the heating sheet and heat the wrapped candidate optical cable.

10. The optical cable fault locating method according to claim 1, characterized in that: The multi-parameter fusion detection device also includes a main control module and a wireless communication module, wherein the main control module is respectively connected to the optical time domain reflectometer module, the distributed vibration sensing module, the distributed optical fiber sensing and temperature measurement module and the wireless communication module, and the main control module is also connected to and controls the optical gating switch; The multi-parameter fusion detection device establishes wireless communication with the intelligent terminal through a built-in wireless communication module; The optical cable fault locating method further comprises: The intelligent terminal sends a gating instruction to the multi-parameter fusion detection device by wireless communication, and the multi-parameter fusion detection device controls the optical gating switch to switch the selected path according to the received gating instruction; And, various detection data acquired by the multi-parameter fusion detection device are received through the intelligent terminal.

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