High-voltage cable distributed optical fiber temperature measurement monitoring device

Abstract

The utility model discloses a distributed optical fiber temperature measurement monitoring device for a high-voltage cable, which relates to the technical field of temperature monitoring and comprises a monitoring host and a temperature measurement optical fiber. One end of the temperature measuring optical fiber is provided with a joint, the joint is connected with the interface, the cross section of the temperature measuring optical fiber sequentially comprises an outer sheath, a woven mesh sleeve, a loose tube and a fiber core from outside to inside, the temperature measuring optical fiber is provided with a plurality of heat conducting rings, the plurality of heat conducting rings are distributed at intervals along the length direction of the temperature measuring optical fiber, and the heat conducting rings sleeve the loose tube and are in contact fixation with the loose tube; the heat conduction ring is located between the woven mesh sleeve and the loose tube. The distributed optical fiber temperature measurement monitoring device for the high-voltage cable can monitor the surface temperature of the high-voltage cable in real time, and has better monitoring sensitivity to temperature change.

Description

Technical Field

[0001] This utility model relates to the field of temperature monitoring technology, and in particular to a distributed optical fiber temperature monitoring device for high-voltage cables. Background Technology

[0002] To ensure the reliable operation of a power supply system, a key factor is the safe operation of power cables. Whether the cable has been operating under prolonged overload or is damaged due to structural defects such as insulation aging or outer sheath breakage, one symptom of a cable accident is that the cable surface temperature exceeds a certain threshold. Therefore, real-time monitoring of the surface temperature of high-voltage cables allows for the timely detection of potential defects and risks, providing early warnings of impending accidents. While optical fibers are used to monitor cable surface temperature, ordinary optical fibers have relatively low sensitivity to temperature. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a distributed fiber optic temperature monitoring device for high-voltage cables, capable of real-time monitoring of the surface temperature of high-voltage cables and exhibiting better sensitivity to temperature changes.

[0004] A high-voltage cable distributed optical fiber temperature monitoring device according to an embodiment of the present utility model includes: a monitoring host, wherein the monitoring host is provided with an interface;

[0005] A temperature-sensing optical fiber is used to lay along the length of a cable. One end of the temperature-sensing optical fiber is provided with a connector, and the connector is connected to the interface. The cross-section of the temperature-sensing optical fiber, from the outside to the inside, includes an outer sheath, a braided mesh sleeve, a loose tube, and a fiber core. The temperature-sensing optical fiber is provided with multiple heat-conducting rings, which are spaced apart along the length of the temperature-sensing optical fiber. The heat-conducting rings are fitted onto the loose tube and are fixed in contact with the loose tube. The heat-conducting rings are located between the braided mesh sleeve and the loose tube.

[0006] The high-voltage cable distributed optical fiber temperature monitoring device according to the present invention has at least the following beneficial effects: the monitoring host emits a laser towards the temperature-measuring optical fiber through the interface. While the laser is propagating in the optical fiber, Raman scattering also occurs. The scattered light can be reflected back to the interface of the monitoring host and received. Raman scattering includes two different wavelengths of reflected light. The intensity of one type of reflected light is not affected by the temperature of the propagation medium, while the intensity of the other type of reflected light depends on the temperature of the propagation medium. The temperature can be calculated by comparing the intensity difference between the two types of reflected light. Multiple heat-conducting rings are set at intervals in the temperature-measuring optical fiber, which can improve the heat conduction efficiency of the cable temperature transfer to the fiber core, thereby improving the temperature sensitivity of the temperature-measuring optical fiber.

[0007] According to some embodiments of the present invention, the interior of the loose tube is filled with a first thermally conductive gel, which encapsulates the fiber core.

[0008] According to some embodiments of the present invention, the space between the outer sheath and the loose tube is filled with the second thermally conductive gel, and the second thermally conductive gel wraps the woven mesh sleeve.

[0009] According to some embodiments of the present invention, along the length direction of the temperature measuring optical fiber, the surface of the outer sheath is provided with a protruding connecting portion, and the connecting portion is provided with a plurality of through holes, which are spaced apart along the length direction of the temperature measuring optical fiber.

[0010] According to some embodiments of the present invention, the outer surface of the temperature-measuring optical fiber is provided with a contact portion, the contact portion extends along the length direction of the temperature-measuring optical fiber, the contact portion is used to fit against the outer wall of the cable, and with the centerline of the temperature-measuring optical fiber as the axis, the contact portion is located on the opposite side of the through hole.

[0011] According to some embodiments of the present invention, in the cross-section of the temperature-sensing optical fiber, the contact portion is recessed toward the center of the temperature-sensing optical fiber to form an arc-shaped profile.

[0012] According to some embodiments of the present invention, a metal strip is provided on the outer side of the loose tube, the metal strip is spirally wound around the loose tube along the length direction of the temperature measuring optical fiber to form armor, and a metal rod is provided on the outer side of the metal strip, the metal rod extending along the length direction of the temperature measuring optical fiber.

[0013] According to some embodiments of the present invention, the inner side of the woven mesh sleeve is provided with tensile fibers, the tensile fibers are arranged along the length direction of the temperature measuring optical fiber, and the tensile fibers wrap the metal strip and the metal rod.

[0014] According to some embodiments of the present invention, at least two fiber cores are provided inside the loose tube.

[0015] According to some embodiments of the present invention, the outer sheath is provided with a marking line, the marking line extends along the length direction of the temperature measuring optical fiber, and the marking line is parallel to the axis of the temperature measuring optical fiber.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1This is a schematic diagram of the structure of the high-voltage cable distributed optical fiber temperature monitoring device according to an embodiment of the present invention;

[0019] Figure 2 This is a cross-sectional view of the temperature-measuring optical fiber according to an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of the heat-conducting ring distributed in the temperature-sensing optical fiber according to an embodiment of the present invention;

[0021] Figure 4 A cross-sectional view of a temperature-sensing optical fiber with a through hole, according to an embodiment of this utility model;

[0022] Figure 5 This is a schematic diagram of the structure of a temperature-measuring optical fiber with a through hole, according to an embodiment of the present invention.

[0023] Icon labels:

[0024] Monitoring host 100, interface 110, temperature measuring fiber optic cable 200, contact part 201, outer sheath 210, through hole 211, braided mesh sleeve 220, loose tube 230, fiber core 240, heat-conducting ring 250, metal strip 260, tensile fiber 270. Detailed Implementation

[0025] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0026] In the description of this utility model, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.

[0028] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0029] As described in the background section, if you want to monitor the surface temperature of a cable, you can install traditional temperature sensors such as thermometers on the surface of the cable. However, this method can only monitor a single point of the cable. In actual operation, the location of a cable fault is uncertain. If the cable cannot be fully monitored, it is also impossible to detect potential defects and risks in the cable in a timely manner.

[0030] Furthermore, if temperature sensors are installed at intervals along the length of the cable, although this can solve the problem of full monitoring of the cable, the large number of sensors required and the fact that each sensor needs to be electrically connected to the monitoring system will greatly increase the monitoring cost.

[0031] Furthermore, fiber optic cables can be used to monitor cable temperature. For example, when a laser beam propagates in an optical fiber, Raman scattering occurs, and the scattered light is reflected back to the host and received. The scattered light can be divided into two different types based on wavelength. Since the scattered light is reflected back to the host, this scattered light is also called reflected light, including Stokes reflection and Antistokes reflection. The wavelength of Stokes reflection is longer than the wavelength of the incident laser beam; the wavelength of Antistokes reflection is shorter than the wavelength of the incident light. Because of the wavelength difference, the host can effectively distinguish between the two types of reflected light and monitor their intensities separately. The intensity of Stokes reflection depends only on the structure of the propagation medium and is independent of its temperature; the intensity of Antistokes reflection depends not only on the structure of the propagation medium but also on its temperature. Since both Stokes and Antistokes reflections propagate in the same optical fiber, their intensities affected by the propagation medium are the same. By comparing the intensity difference between Stokes and Antistokes reflections, the temperature experienced by the optical fiber can be calculated.

[0032] After the host emits a laser, it continuously receives reflected light from the optical fiber. Furthermore, since the propagation speeds of Stokes and Antistokes reflected light in the optical fiber are constant, the time difference between the host's laser emission and receipt of abnormal reflected light can be recorded. Using the known propagation speeds, the distance between the location of the temperature anomaly detected by the optical fiber and the host can be calculated. It's important to understand that abnormal reflected light here refers to the intensity difference between Stokes and Antistokes reflected light exceeding a threshold, meaning the temperature sensed by the optical fiber at that location differs significantly from the surrounding ambient temperature.

[0033] It's also important to understand that Stokes and Antistoke reflected light are generally mixed. A spectral separation module can decompose this mixed light into Stokes and Antistoke reflected light of different wavelengths. These beams then illuminate a photoelectric conversion element, generating electrical signals corresponding to their intensities. Processing these signals and performing comparative calculations allows for the determination of the temperature distribution curve along the fiber's length. Both the spectral separation module and the photoelectric conversion element are mature and readily available technologies, and will not be elaborated upon here. However, ordinary optical fibers prioritize the propagation of light signals, resulting in generally poor or even absent thermal conductivity. When the surface temperature of the cable rises, ordinary optical fibers struggle to quickly detect temperature changes, exhibiting low sensitivity to temperature sensing.

[0034] Reference Figure 1 and Figure 2 As shown, a high-voltage cable distributed optical fiber temperature monitoring device according to an embodiment of the present invention includes a monitoring host 100 and a temperature measuring optical fiber 200.

[0035] The monitoring host 100 is provided with an interface 110; the temperature measuring optical fiber 200 is used to lay along the length of the cable and is attached to the cable so that the temperature of the cable surface can be transferred to the temperature measuring optical fiber 200; one end of the temperature measuring optical fiber 200 is provided with a connector and the connector is connected to the interface 110. The cross-section of the temperature measuring optical fiber 200 includes, from the outside to the inside, an outer sheath 210, a braided mesh sleeve 220, a loose tube 230 and a fiber core 240. The temperature measuring optical fiber 200 also includes multiple heat-conducting rings 250. The multiple heat-conducting rings 250 are distributed at intervals along the length of the temperature measuring optical fiber 200. The heat-conducting rings 250 are fitted into the loose tube 230 and are fixed in contact with the loose tube 230. The heat-conducting rings 250 are located between the braided mesh sleeve 220 and the loose tube 230.

[0036] Reference Figure 3As shown, the temperature-sensing optical fiber 200 is virtually divided into multiple temperature-sensing segments of equal length, each with a heat-conducting ring 250. The heat-conducting ring 250 can be made of a material with a higher thermal conductivity than the loose tube 230, such as copper or aluminum, making its thermal conductivity higher than that of the loose tube 230. Therefore, in each virtual temperature-sensing segment, the heat-conducting ring 250 more easily concentrates heat, and the location of the heat-conducting ring 250 is more sensitive to temperature, further increasing the sensitivity of the fiber core 240 to ambient temperature. Assuming the surface temperature of the power cable is too high, exceeding a threshold, the temperature-sensing optical fiber 200 with the heat-conducting ring 250 more easily concentrates the cable's heat at the heat-conducting ring 250. Compared to ordinary optical fiber, the heat-conducting ring 250 causes a greater temperature change in the fiber core 240, resulting in a more significant change in the intensity of the Antistokes reflected light. The difference in intensity between the Stokes reflected light and the Antistokes reflected light is greater, making it easier to calculate the cable's surface temperature and determine whether the cable temperature exceeds the threshold.

[0037] It should be understood that the temperature monitored at the location of the heat-conducting ring 250 can be equivalently understood as the average temperature of that temperature measurement segment.

[0038] Furthermore, the temperature-sensing optical fiber 200 is laid along the power cable, and it requires higher abrasion resistance and tensile strength. The outer sheath 210 provides abrasion resistance, the braided mesh 220 has good tensile strength, and the fiber core 240, as the laser propagation medium, is placed in the loose tube 230 to protect the fiber core 240 from friction damage from the braided mesh 220.

[0039] The appropriate length of the temperature-sensing optical fiber 200 can be selected according to the length of the cable to be monitored. A connector is provided at one end of the temperature-sensing optical fiber 200, and the temperature-sensing optical fiber 200 is connected to the monitoring host 100 through the connection and cooperation of the connector and the interface 110. The monitoring host 100 can emit laser light to the temperature-sensing optical fiber 200 through the interface 110. Preferably, the monitoring host 100 emits pulsed laser light.

[0040] It should be understood that the monitoring host 100 also includes the system carrier and the monitoring computing software that runs, all of which are existing technologies and will not be described in detail here.

[0041] Understandably, the interior of the loose tube 230 is filled with a first thermally conductive gel, which encapsulates the fiber core 240.

[0042] Since the laser emitted by the monitoring host 100, as well as the Stokes and Antistokes reflected light, all propagate within the fiber core 240 and are significantly affected by temperature, a first thermally conductive gel can be filled into the loose tube 230 to improve the monitoring sensitivity of the temperature-sensing fiber 200. This first thermally conductive gel completely fills the air gaps in the loose tube 230, resulting in a higher thermal conductivity. Temperature changes in the external environment are more easily transmitted to the fiber core 240 and affect the intensity difference between the Stokes and Antistokes reflected light, which is beneficial for the monitoring host 100 to acquire more sensitive parameters.

[0043] It is important to understand that the first thermally conductive gel is a viscous substance with high thermal conductivity, usually in the form of a paste or gel, and is mainly composed of metal oxide powders (such as silver, copper, aluminum, and zinc) and a silicone oil matrix. Existing products can be used for the first thermally conductive gel, so they will not be described in detail here.

[0044] Understandably, a second thermally conductive gel is filled between the outer sheath 210 and the loose tube 230, and the second thermally conductive gel wraps around the braided mesh sleeve 220.

[0045] Since the braided mesh sleeve 220 may not be embedded in the outer sheath 210, and the braided mesh sleeve 220 is movable between the outer sheath 210 and the loose tube 230, there will be a relatively large gap between the outer sheath 210 and the loose tube 230. After the temperature-sensing optical fiber 200 is laid, the heat generated by the power cable needs to pass through the outer sheath 210, the braided mesh sleeve 220, and the loose tube 230 before being transferred to the fiber core 240. Similarly, in order to improve the thermal conductivity between the outer sheath 210 and the loose tube 230, a second thermally conductive gel can be filled between the outer sheath 210 and the loose tube 230. It should be understood that the second thermally conductive gel can use the same material as the first thermally conductive gel.

[0046] Reference Figure 4 and Figure 5 As shown, it can be understood that, along the length of the temperature measuring fiber 200, the surface of the outer sheath 210 is provided with a protruding connecting part, and the connecting part is provided with multiple through holes 211, which are distributed at intervals along the length of the temperature measuring fiber 200.

[0047] The temperature-sensing optical fiber 200 is mainly used to lay on the outer surface of the cable. However, the outer shell of the cable is arc-shaped, making it difficult to fix the temperature-sensing optical fiber 200 and the cable. The connecting part of the outer sheath 210 is provided with multiple through holes 211. Cable ties or straps can be passed through the through holes 211 and tied to the cable to fix the temperature-sensing optical fiber 200 to the outer surface of the cable, which can achieve a good fixing effect.

[0048] Furthermore, it can be understood that the outer surface of the temperature measuring fiber 200 is also provided with a contact portion 201. The contact portion 201 extends along the length direction of the temperature measuring fiber 200 and is used to fit the outer wall of the cable. With the center line of the temperature measuring fiber 200 as the axis, the contact portion 201 is located on the opposite side of the through hole 211.

[0049] The contact portion 201 reduces slippage of the temperature-sensing optical fiber 200 on the cable surface. Specifically, the contact portion 201 can be manufactured by material removal, for example, by cutting along the length of the temperature-sensing optical fiber 200 to form a flat contact surface. The contact portion 201 is located on the opposite side of the through hole 211, allowing it to contact the cable surface. Simultaneously, a strap is used to secure the temperature-sensing optical fiber 200 to the cable through the through hole 211. The contact portion 201 prevents slippage of the temperature-sensing optical fiber 200 and inhibits its circumferential rotation.

[0050] It is understandable that in the cross-section of the temperature-sensing optical fiber 200, the contact portion 201 is recessed toward the center of the temperature-sensing optical fiber 200 to form an arc-shaped profile.

[0051] Furthermore, the arc-shaped profile formed by the contact portion 201 can fit well with the outer surface of the cable, increasing the contact area between the temperature-sensing optical fiber 200 and the cable, and further improving the heat transfer efficiency between the cable and the temperature-sensing optical fiber 200.

[0052] It is understood that a metal strip 260 is provided on the outside of the loose tube 230. The metal strip 260 is spirally wound around the loose tube 230 along the length of the temperature measuring optical fiber 200 to form armor. A metal rod is provided on the outside of the metal strip 260, and the metal rod extends along the length of the temperature measuring optical fiber 200.

[0053] The armor structure formed by the metal strip 260 and the metal rod are both designed to prevent the temperature-sensing fiber 200 from being damaged due to excessive bending.

[0054] Understandably, the inner side of the braided mesh sleeve 220 is provided with tensile fibers 270, which are arranged along the length of the temperature-sensing optical fiber 200 and wrap around the metal strip 260 and the metal rod. The tensile fibers 270 can further improve the tensile strength of the temperature-sensing optical fiber 200. The tensile fibers 270 can be made of materials such as Kevlar.

[0055] It is understandable that the loose tube 230 contains at least two fiber cores 240.

[0056] For example, two fiber cores 240 can be installed in the loose tube 230, and the same temperature-sensing fiber 200 can have two connectors, which are connected to two different interfaces 110 of the monitoring host 100 respectively. Two sets of data can be obtained through a single temperature-sensing fiber 200, and the two sets of data can be cross-checked to determine the situation of false alarms.

[0057] It is understandable that the outer sheath 210 is provided with marking lines that extend along the length of the temperature measuring optical fiber 200 and are parallel to the axis of the temperature measuring optical fiber 200.

[0058] When laying the temperature-sensing optical fiber 200, the marking line on the outer sheath 210 can be observed. If the marking line is spiral, the surface temperature-sensing optical fiber 200 is circumferentially twisted. At this time, the temperature-sensing optical fiber 200 needs to be adjusted in the opposite direction to keep the marking line parallel to the axis of the temperature-sensing optical fiber 200, so as to prevent the temperature-sensing optical fiber 200 from breaking due to excessive twisting.

[0059] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A high-voltage cable distributed optical fiber temperature monitoring device, characterized by, The utility model relates to a temperature monitoring system, comprising: a monitoring host (100) provided with an interface (110); a temperature measuring optical fiber (200) provided with a connector at one end, the connector being connected to the interface (110), the temperature measuring optical fiber (200) comprising, from outside to inside, an outer sheath (210), a braided mesh cover (220), a loose sleeve (230), and a fiber core (240), the temperature measuring optical fiber (200) being provided with a plurality of heat-conducting rings (250) distributed along the length direction of the temperature measuring optical fiber (200), the heat-conducting rings (250) being sleeved on and fixedly connected to the loose sleeve (230), and the heat-conducting rings (250) being located between the braided mesh cover (220) and the loose sleeve (230).

2. The distributed optical fiber temperature monitoring apparatus for high voltage cables according to claim 1, characterized in that, The inside of the loose sleeve (230) is filled with a first heat-conducting gel, which wraps the fiber core (240).

3. The distributed optical fiber temperature monitoring apparatus for high voltage cables according to claim 2, characterized in that, The space between the outer sheath (210) and the loose sleeve (230) is filled with a second heat-conducting gel, which wraps the braided mesh cover (220).

4. The distributed optical fiber temperature monitoring system for high voltage cables according to claim 1, characterized in that, Along the length direction of the temperature measuring optical fiber (200), the surface of the outer sheath (210) is provided with a protruding connecting part, the connecting part being provided with a plurality of through holes (211) distributed along the length direction of the temperature measuring optical fiber (200).

5. A distributed optical fibre temperature monitoring apparatus for a high voltage cable according to claim 4, characterised in that, The outer surface of the temperature measuring optical fiber (200) is provided with a contact part (201) extending along the length direction of the temperature measuring optical fiber (200), the contact part (201) being used to adhere to the outer wall of a cable, and the contact part (201) being located on the opposite side of the through holes (211) with the center line of the temperature measuring optical fiber (200) as the axis.

6. The distributed optical fiber temperature monitoring apparatus for high voltage cables according to claim 5, characterized in that, In the cross section of the temperature measuring optical fiber (200), the contact part (201) is recessed towards the center of the temperature measuring optical fiber (200) to form an arc-shaped profile.

7. The distributed optical fiber temperature monitoring system for high voltage cables according to claim 1, characterized in that, The outer side of the loose sleeve (230) is provided with a metal band (260) spirally wound on the loose sleeve (230) along the length direction of the temperature measuring optical fiber (200) to form an armor, and the outer side of the metal band (260) is provided with a metal rod extending along the length direction of the temperature measuring optical fiber (200).

8. The distributed optical fiber temperature monitoring apparatus for high voltage cables according to claim 7, characterized in that, The inner side of the braided mesh cover (220) is provided with a tensile fiber (270) arranged along the length direction of the temperature measuring optical fiber (200), and the tensile fiber (270) wraps the metal band (260) and the metal rod.

9. The distributed optical fiber temperature monitoring system for high voltage cables according to claim 1, characterized in that, At least two fiber cores (240) are arranged in the loose sleeve (230).

10. The distributed optical fiber temperature monitoring apparatus for high voltage cables according to claim 1, characterized in that, The outer sheath (210) is provided with a mark line extending along the length direction of the temperature measuring optical fiber (200), and the mark line is parallel to the axis of the temperature measuring optical fiber (200).

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