Multifunctional intermediate joint capable of connecting cable

Abstract

The invention provides a multifunctional intermediate joint capable of being connected with a cable, and relates to the technical field of cable accessories. The multifunctional intermediate joint capable of connecting the cable comprises a joint body, an operation and maintenance hand-held terminal based on RFID and GPS, and an Internet of Things platform. In the case of instantaneous overload or short circuit, the PCM quickly absorbs heat to delay temperature rise, and the axial flow fan forcibly cools air to discharge heat, so that insulation carbonization is avoided; the self-cleaning mechanism removes dust on the filter screen to ensure stable long-term heat dissipation; the STM32H743VIT6 is fused with temperature, mechanical stress, partial discharge data and time-frequency domain alignment, so that the insulation failure prediction precision is improved; the dual-frequency anti-metal RFID tag, UWB positioning and AR operation and maintenance terminal are linked to display the health state, the deterioration trend and the maintenance animation of the connector in real time, so that the inspection time is greatly shortened, and misoperation is reduced; the Internet of Things platform remotely calls edge calculation data, experts collaboratively mark AR pictures, and the fault response speed is increased; and a sensing-analysis-decision-execution intelligent operation and maintenance system is constructed.

Description

Technical Field

[0001] The present invention relates to the technical field of cable accessories, and particularly to a multifunctional intermediate joint capable of connecting cables. Background Art

[0002] An intermediate cable joint is a cable joint at the middle part of a cable line. The intermediate joint is a cable accessory used for the intermediate connection of cross-linked cables or oil-immersed cables of various voltage levels. Its main functions are to keep the line unobstructed, keep the cable sealed, and ensure the insulation level at the cable joint, so that it can operate safely and reliably; cable intermediate joints can be divided into two types: fixed type and movable type. The fixed intermediate joint has a stable structure and is suitable for the connection of cables with long-term fixation and high-voltage transmission.

[0003] With the development of the power system towards high voltage and intelligence, as a key node in the power transmission network, the reliability of cable intermediate joints faces multiple challenges:

[0004] The risk of high-temperature breakdown is aggravated: Traditional joints rely on the metal shielding layer to conduct heat for passive heat dissipation. During instantaneous overload or short circuit, the heat dissipation efficiency is insufficient, which is likely to cause carbonization of insulating materials and lead to breakdown accidents; there are also technologies that propose air-cooled or liquid-nitrogen cooling structures. The existing air-cooled structures are insufficient to cope with the high temperatures generated during instantaneous overload or short circuit, and the existing air-cooled systems have reduced heat dissipation efficiency due to dust accumulation and require frequent manual cleaning, resulting in high maintenance costs; the liquid-nitrogen cooling structure needs to be replenished regularly. When in use, the local temperature drops suddenly, which may cause brittle fracture of materials. Moreover, the volume expansion of liquid nitrogen vaporization is very large. If the sealing structure design is improper, the internal pressure may increase suddenly, which may cause the outer sheath layer of the joint to burst.

[0005] The intelligent operation and maintenance ability is weak: At present, most joints only support single-parameter monitoring and lack the ability to analyze multi-physical field coupling data, and cannot predict potential faults such as mechanical deformation and partial discharge; moreover, traditional operation and maintenance rely on inefficient manual inspections (requiring special equipment to detect point by point) and off-line diagnosis, and it is difficult to achieve real-time status visualization, remote decision support, and precise guidance for on-site operations.

[0006] Therefore, it is necessary to develop a multifunctional intermediate joint capable of connecting cables to solve the above problems. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a multifunctional intermediate joint capable of connecting cables, which solves the problems of aggravated risk of high-temperature breakdown and weak intelligent operation and maintenance ability existing in the multifunctional intermediate joint capable of connecting cables in the prior art.

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions: A multifunctional intermediate joint capable of connecting cables, comprising a joint body, an operation and maintenance handheld terminal based on RFID and GPS, and an Internet of Things platform. The joint body is fixedly connected to the cable joint. The joint body includes a conductor connection layer, an inner semiconductive layer, a main insulation layer, a heat conduction layer, an outer semiconductive layer, a metal shielding layer, a protective layer, an outer sheath layer, and an external heat dissipation structure for heat dissipation. The external heat dissipation structure includes a heat dissipation layer, an air outlet ring pipe, a blowing pipe, a two-way axial flow fan, and a self-cleaning mechanism. The air outlet ring pipe and the heat dissipation layer are arranged in sequence on the outer wall of the outer sheath layer in the front-back distribution. The blowing pipe is arranged on the side wall of the air outlet ring pipe. The two-way axial flow fan is arranged inside the blowing pipe;

[0009] The heat conduction layer is composed of multiple groups of PCM rings and multiple groups of heat conduction rings that are axially spaced apart. The multiple groups of PCM rings and heat conduction rings are all arranged on the outer wall of the main insulation layer. The PCM ring is a paraffin-based phase change material encapsulated in a ring-shaped copper-graphene composite shell. The heat conduction ring is a ring-shaped graphene-copper heat conduction bridge;

[0010] A waterproof chamber is arranged on the outer wall of the outer sheath layer and in front of the air outlet ring pipe. Inside the waterproof chamber, there are arranged a dual-frequency anti-metal RFID tag, an edge computing module, and a lithium thionyl chloride battery for connecting the joint to the operation and maintenance handheld terminal and the Internet of Things platform. On the joint body, there are arranged a gas sensor, a temperature sensor, a piezoelectric ceramic sheet, a micro capacitive probe, a distributed optical fiber, and a humidity sensor for real-time monitoring of multi-physical quantity coupling fields of the joint body's multi-dimensional parameters. And through the edge computing module, multi-source heterogeneous data is fused and processed to generate the health status information of the joint body.

[0011] Preferably, the heat dissipation layer is composed of an inner heat dissipation pipe, a honeycomb support structure, and an outer heat dissipation pipe arranged in sequence from the inside to the outside. The inner heat dissipation pipe, the honeycomb support structure, and the outer heat dissipation pipe are all made of aluminum alloy. Inside the honeycomb support structure, there are arranged multiple groups of hexagonal honeycomb holes. The multiple groups of hexagonal honeycomb holes penetrate through the front and rear ends of the heat dissipation layer to form air ducts. The outer diameter of the air outlet ring pipe is smaller than the inner diameter of the outer heat dissipation pipe and larger than the outer diameter of the inner heat dissipation pipe. An air outlet chamber is arranged inside the air outlet ring pipe. One end of the air outlet chamber facing the heat dissipation layer is provided with an air outlet. The air outlet is opposite to the air duct. One end of the blowing pipe facing the air outlet ring pipe is internally connected to the air outlet chamber. The end of the blowing pipe away from the air outlet ring pipe is detachably connected with a filter plate. A filter net is arranged on the inner side wall of the filter plate. The filter net is cleaned by the two-way axial flow fan and the self-cleaning mechanism;

[0012] The self-cleaning mechanism includes a waterproof motor, a rotating rod, and multiple groups of brush filaments. The waterproof motor is fixedly connected to the inner side wall of the air blowing pipe through a fixed bracket. The rotating rod is fixedly connected to the end of the protruding shaft of the waterproof motor. The middle position in the length direction of the rotating rod is connected to the end of the protruding shaft of the waterproof motor, and the axis of the rotating rod is perpendicular to the axis of the protruding shaft of the waterproof motor. Multiple groups of the brush filaments are all fixedly connected to the side of the rotating rod away from the waterproof motor, and the sides of multiple groups of the brush filaments away from the rotating rod are all in contact with the side of the filter net facing the inside of the air blowing pipe;

[0013] The dual frequencies of the dual-frequency anti-metal RFID tag are the high-frequency band and the ultra-high-frequency band. The dual-frequency anti-metal RFID tag is built-in with a UWB module. The edge computing module consists of an NPU co-processor, a low-power Bluetooth 5.2 module, an STM32H743VIT6, an NPU acceleration chip, and an ublox ZED-F9P positioning module;

[0014] A graphene heat-conducting sheet is arranged on the inner side wall of the PCM ring. The graphene heat-conducting sheet covers 100% of the area of the inner side wall of the PCM ring. A copper wire mesh is arranged on the circumferential outer wall of the PCM ring. The copper wire mesh covers 80% of the area of the outer wall of the PCM ring. The wire diameter of the copper wire in the copper wire mesh is 0.2 mm.

[0015] Preferably, the conductor connection layer is a silver-plated copper compression joint. The conductor connection layer is connected at the cable joint. A groove is arranged on the outer wall of the conductor connection layer and near the middle position. The temperature sensor is arranged inside the groove.

[0016] Preferably, the inner semi-conductive layer is EPDM doped with carbon nanotubes. The micro capacitive probe is arranged on the inner wall of the inner semi-conductive layer. There are six groups of the micro capacitive probes. The six groups of the micro capacitive probes are evenly distributed in a circumferential equidistant manner with the axis of the inner semi-conductive layer as the center.

[0017] Preferably, the main insulation layer is nano-aluminum trioxide modified XLPE. The distributed optical fiber is spirally wound around the inner side wall of the main insulation layer. The distributed optical fiber uses a Φ0.25 mm bend-resistant optical fiber. The pitch of the spiral winding of the distributed optical fiber is 10 - 15 mm.

[0018] Preferably, the outer semi-conductive layer is conductive silicone rubber. Stress cones are arranged at both circumferential ends of the outer semi-conductive layer. There are two groups of piezoelectric ceramic sheets. The two groups of piezoelectric ceramic sheets are respectively arranged on the inner side wall of a group of stress cones.

[0019] Preferably, the metal shielding layer is composed of a copper braided tape and a corrugated aluminum tube distributed inside and outside. A Rogowski coil and an inductive power-taking coil are arranged on the outer wall of the corrugated aluminum tube. The Rogowski coil and the inductive power-taking coil are shielded by a permalloy layer with a thickness of 0.1 mm.

[0020] Preferably, the protective layer is composed of a buffer layer, a flame retardant layer and a waterproof layer which are distributed inside and outside. The buffer layer is silicone rubber foam, the flame retardant layer is a ceramized silicone rubber containing microcapsules, and the microcapsules are internally encapsulated with an APP / PER / MEL system flame retardant. The waterproof layer is fluororubber, and the humidity sensor is arranged on the inner wall of the waterproof layer.

[0021] Preferably, the outer sheath layer is polyurethane with an anti-ultraviolet rating of UV-A.

[0022] Preferably, the gas sensor is arranged on the upper wall of the waterproof bin.

[0023] The present invention provides a multifunctional intermediate joint that can be connected to a cable. It has the following beneficial effects:

[0024] 1. Compared with the prior art, for the multifunctional intermediate joint that can be connected to a cable, through the collaborative heat dissipation design of the PCM phase change material and the graphene heat conduction bridge, combined with the two-way axial flow fan and the self-cleaning mechanism, the dynamic balance of active heat dissipation and passive heat storage is achieved; in case of instantaneous overload or short circuit, the PCM phase change material quickly absorbs heat to delay the temperature rise, and at the same time the axial flow fan forces air cooling to efficiently discharge heat, avoiding carbonization of the insulating layer; the self-cleaning mechanism can automatically remove dust on the filter screen to ensure long-term heat dissipation stability, and solves the problem of frequent maintenance caused by the attenuation of heat dissipation efficiency in the traditional solution.

[0025] 2. Compared with the prior art, for the multifunctional intermediate joint that can be connected to a cable, through the STM32H743VIT6 processor to perform time-frequency domain fusion on heterogeneous data such as temperature, mechanical stress, and partial discharge, the spatio-temporal alignment of multi-source data is realized, and the accuracy of predicting the risk of insulation failure is greatly improved; combined with the dual-frequency anti-metal RFID tag, UWB precise positioning and the AR operation and maintenance handheld terminal, on-site personnel can obtain the joint health status, historical deterioration trend and maintenance guidance animation in real time through the AR interface, greatly reducing the single-point inspection time and at the same time reducing the situation of misoperation; the Internet of Things platform supports experts to remotely retrieve the compressive sensing data of the edge computing module and perform collaborative annotation on the AR picture to improve the fault diagnosis response speed; breaking through the limitations of the traditional solution with a single monitoring dimension and lagging offline diagnosis, a full-chain intelligent operation and maintenance system of "perception - analysis - decision - execution" is established. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the present invention;

[0027] Figure 2 is a cross-sectional view of the joint body of the present invention;

[0028] Figure 3 is the present invention Figure 2 partial enlarged view at A in;

[0029] Figure 4 This is a partial top view cross-sectional view of the heat dissipation layer, air outlet ring pipe and air blowing pipe connection structure of the present invention;

[0030] Figure 5 For the present invention Figure 4 Partial enlarged view at position B in;

[0031] Figure 6 This is a partial cross-sectional view of the internal structure of the waterproof bin of the present invention;

[0032] Figure 7 This is a partial cross-sectional view of the connection structure between the outer semi-conductive layer and the stress cone of the present invention;

[0033] Figure 8 This is a partial schematic view of the connection structure between the main insulation layer and the distributed optical fiber of the present invention;

[0034] Figure 9 This is a partial schematic view of the structure of the heat conduction layer of the present invention;

[0035] Figure 10 This is a partial cross-sectional view of the internal structure of the protective layer of the present invention.

[0036] Among them, 1. Conductor connection layer; 2. Inner semi-conductive layer; 3. Main insulation layer; 4. Heat conduction layer; 5. Outer semi-conductive layer; 6. Metal shielding layer; 7. Protective layer; 8. Outer sheath layer; 9. Heat dissipation layer; 901. Inner heat dissipation pipe; 902. Honeycomb support structure; 903. Outer heat dissipation pipe; 10. Waterproof bin; 11. Air outlet ring pipe; 1101. Air outlet cavity; 1102. Air outlet; 12. Air blowing pipe; 13. Filter plate; 14. Filter net; 15. Bidirectional axial flow fan; 16. PCM ring; 17. Heat conduction ring; 18. Graphene heat conduction sheet; 19. Copper wire mesh; 20. Buffer layer; 21. Flame retardant layer; 22. Waterproof layer; 23. Humidity sensor; 24. Dual-frequency anti-metal RFID tag; 25. Edge computing module; 26. Lithium thionyl chloride battery; 27. Gas sensor; 28. Fixed bracket; 29. Waterproof motor; 30. Rotating rod; 31. Brush wire; 32. Temperature sensor; 33. Stress cone; 34. Piezoelectric ceramic sheet; 35. Micro capacitive probe; 36. Distributed optical fiber. Specific embodiments

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment:

[0039] As Figures 1 to 10 shown, an embodiment of the present invention provides a multi-functional intermediate joint capable of connecting cables, including a joint body, an operation and maintenance handheld terminal based on RFID and GPS, and an Internet of Things platform. The joint body is fixedly connected to the cable joint. The joint body includes a conductor connection layer 1, an inner semi-conductive layer 2, a main insulation layer 3, a heat conduction layer 4, an outer semi-conductive layer 5, a metal shielding layer 6, a protective layer 7, an outer sheath layer 8, and an external heat dissipation structure for heat dissipation, which are arranged in sequence from the inside to the outside;

[0040] To achieve long-term heat dissipation and dust prevention maintenance under normal operating conditions of the cable joint, the external heat dissipation structure includes a heat dissipation layer 9, an air outlet ring pipe 11, a blowing pipe 12, a bidirectional axial flow fan 15, and a self-cleaning mechanism. The air outlet ring pipe 11 and the heat dissipation layer 9 are arranged in sequence on the outer wall of the outer sheath layer 8 in the front and rear distribution. The heat dissipation layer 9 is composed of an inner heat dissipation pipe 901, a honeycomb support structure 902, and an outer heat dissipation pipe 903, which are arranged in sequence from the inside to the outside. The inner heat dissipation pipe 901, the honeycomb support structure 902, and the outer heat dissipation pipe 903 are all made of aluminum alloy. Multiple groups of hexagonal honeycomb holes are arranged inside the honeycomb support structure 902. The multiple groups of hexagonal honeycomb holes penetrate through the front and rear ends of the heat dissipation layer 9 to form an air duct; the outer diameter of the air outlet ring pipe 11 is smaller than the inner diameter of the outer heat dissipation pipe 903 and larger than the outer diameter of the inner heat dissipation pipe 901. An air outlet cavity 1101 is arranged inside the air outlet ring pipe 11. An air outlet 1102 is arranged at one end of the air outlet cavity 1101 facing the heat dissipation layer 9, and the air outlet 1102 faces the air duct; the blowing pipe 12 is arranged on the side wall of the air outlet ring pipe 11, the bidirectional axial flow fan 15 is arranged inside the blowing pipe 12, and one end of the blowing pipe 12 facing the air outlet ring pipe 11 communicates with the inside of the air outlet cavity 1101,

[0041] During normal operation of the cable, the heat dissipation layer 9 dissipates heat passively through the high heat radiation rate of the aluminum alloy material; when the temperature rise threshold is monitored, the axial flow fan 15 starts to enhance convection, and the heat dissipation efficiency is greatly improved compared with the pure passive solution;

[0042] To achieve long-term dust prevention of the bidirectional axial flow fan 15, a filter plate 13 is detachably connected to one end of the blowing pipe 12 away from the air outlet ring pipe 11. A filter net 14 is arranged on the inner side wall of the filter plate 13. The filter net 14 is cleaned by the bidirectional axial flow fan 15 and the self-cleaning mechanism. The self-cleaning mechanism includes a waterproof motor 29, a rotating rod 30, and multiple groups of brush filaments 31. The waterproof motor 29 is fixedly connected to the inner side wall of the blowing pipe 12 through a fixed bracket 28. The rotating rod 30 is fixedly connected to the end of the protruding shaft of the waterproof motor 29. The middle position in the length direction of the rotating rod 30 is connected to the end of the protruding shaft of the waterproof motor 29, and the axis of the rotating rod 30 is perpendicular to the axis of the protruding shaft of the waterproof motor 29. Multiple groups of brush filaments 31 are all fixedly connected to the side of the rotating rod 30 away from the waterproof motor 29. One side of multiple groups of brush filaments 31 away from the rotating rod 30 abuts against the side of the filter net 14 facing the inside of the blowing pipe 12;

[0043] After starting for a certain period of time, backflush through the two-way axial flow fan 15, and drive the brush wire 31 to clean the filter screen 14 by the waterproof motor 29. The self-cleaning mechanism can remove more than 90% of the dust on the filter screen, ensure that the annual heat dissipation efficiency decay ≤ 5%, and effectively reduce the frequency of manual cleaning;

[0044] In order to block the insulation thermal runaway caused by the instantaneous overload of the cable joint, the heat conduction layer 4 is composed of multiple groups of PCM rings 16 and multiple groups of heat conduction rings 17 that are axially spaced apart. The multiple groups of PCM rings 16 and heat conduction rings 17 are both arranged on the outer wall of the main insulation layer 3. The PCM ring 16 is a paraffin-based phase change material encapsulated in a ring-shaped copper-graphene composite shell. The heat conduction ring 17 is a ring-shaped graphene-copper heat conduction bridge. A graphene heat conduction sheet 18 is arranged on the inner side wall of the PCM ring 16, and the graphene heat conduction sheet 18 covers 100% of the area of the inner side wall of the PCM ring 16. A copper wire mesh 19 is arranged on the circumferential outer wall of the PCM ring 16, and the copper wire mesh 19 covers 80% of the area of the outer wall of the PCM ring 16. The wire diameter of the copper wire in the copper wire mesh 19 is 0.2 mm;

[0045] When the cable suddenly short-circuits or is overloaded, the PCM ring 16 quickly absorbs the Joule heat (phase change latent heat ≥ 180 kJ / kg) transmitted by the conductor connection layer 1 through solid-liquid phase change. The graphene heat conduction sheet 18 evenly diffuses the heat to the adjacent heat conduction ring 17, and the copper wire mesh 19 dissipates heat through radiation assistance, reducing the temperature rise rate of the main insulation layer 3 by more than 60% and effectively avoiding the carbonization of XLPE insulation;

[0046] For the functional analysis and effect quantification of the multi-physical field sensing network, a waterproof chamber 10 is provided on the outer wall of the outer sheath layer 8 and in front of the air outlet ring pipe 11. Inside the waterproof chamber 10, there are a dual-frequency anti-metal RFID tag 24, an edge computing module 25, and a lithium thionyl chloride battery 26 for connecting the joint to the operation and maintenance handheld terminal and the Internet of Things platform. The dual frequency of the dual-frequency anti-metal RFID tag 24 is the high-frequency band and the ultra-high-frequency band. The dual-frequency anti-metal RFID tag 24 is built-in with a UWB module. The edge computing module 25 consists of an NPU coprocessor, a low-power Bluetooth 5.2 module, an STM32H743VIT6, an NPU acceleration chip, and an ublox ZED-F9P positioning module; on the joint body, there are a gas sensor 27, a temperature sensor 32, a piezoelectric ceramic sheet 34, a micro capacitive probe 35, a distributed optical fiber 36, and a humidity sensor 23 for real-time monitoring of the multi-physical quantity coupling field of the joint body. The multi-source heterogeneous data is fused and processed through the edge computing module 25 to generate the health status information of the joint body; the conductor connection layer 1 is a silver-plated copper compression joint pipe, which is connected at the cable joint. There is a groove on the outer wall of the conductor connection layer 1 and near the middle position, and the temperature sensor 32 is arranged inside the groove; the inner semi-conductive layer 2 is EPDM doped with carbon nanotubes, and the micro capacitive probe 35 is arranged on the inner wall of the inner semi-conductive layer 2. There are six groups of micro capacitive probes 35, and the six groups of micro capacitive probes 35 are evenly distributed in a circumferential equidistant manner with the axis of the inner semi-conductive layer 2 as the center; the main insulation layer 3 is nano-aluminum trioxide modified XLPE, and the distributed optical fiber 36 is spirally wound around the inner side wall of the main insulation layer 3. The distributed optical fiber 36 uses a Φ0.25mm bend-resistant optical fiber, and the spiral winding pitch of the distributed optical fiber 36 is 10 - 15mm; the outer semi-conductive layer 5 is conductive silicone rubber, and stress cones 33 are provided at both circumferential ends of the outer semi-conductive layer 5. There are two groups of piezoelectric ceramic sheets 34, and the two groups of piezoelectric ceramic sheets 34 are respectively arranged on the inner side wall of a group of stress cones 33; the metal shielding layer 6 consists of a copper braid and a corrugated aluminum pipe distributed inside and outside. A Rogowski coil and an inductive power-taking coil are arranged on the outer wall of the corrugated aluminum pipe, and the Rogowski coil and the inductive power-taking coil are shielded by a permalloy layer with a thickness of 0.1mm; the protective layer 7 consists of a buffer layer 20, a flame retardant layer 21, and a waterproof layer 22 distributed inside and outside. The buffer layer 20 is silicone rubber foam, the flame retardant layer 21 is a ceramized silicone rubber containing microcapsules, and the microcapsules are internally encapsulated with an APP / PER / MEL system flame retardant. The waterproof layer 22 is fluororubber, and the humidity sensor 23 is arranged on the inner wall of the waterproof layer 22; the outer sheath layer 8 is polyurethane with an anti-ultraviolet grade of UV-A; the gas sensor 27 is arranged on the upper wall of the waterproof chamber 10;

[0047] The temperature sensor 32 is in direct contact with the silver-plated copper crimping tube of the conductor connection layer 1. The sampling frequency is 1 kHz. The data is converted into a temperature gradient map by the ADC module of STM32H743VIT6. The temperature sensor 32 monitors the temperature rise of the contact resistance of the conductor connection layer 1 in real time, captures local overheating caused by loosening or corrosion, and eliminates electromagnetic interference through the Kalman filtering algorithm of the edge computing module 25, making the temperature rise detection response time ≤ 200 ms, which is greatly improved compared with the traditional scheme;

[0048] The gas sensor 27 starts a gas sampling cycle every 5 minutes and switches to the continuous monitoring mode under abnormal conditions. The data is uploaded to the cloud database through the Bluetooth 5.2 module: The gas sensor 27 detects characteristic gases such as CO, H2, and C2H2 generated by the thermal decomposition of insulating materials (detection limit ≤ 10 ppm) to identify early partial discharge or overheating defects; Using the nano-catalytic sensitive film technology, the gas identification accuracy rate ≥ 98%, and combined with the LSTM time series analysis of the edge computing module 25, the insulation degradation warning can be advanced by 6 - 8 hours;

[0049] The piezoelectric ceramic sheet 34 is conformally attached to the silicone rubber matrix of the stress cone 33, and the signal is conditioned by a charge amplifier and then input into the DSP core of STM32 for time-frequency domain feature extraction;

[0050] The piezoelectric ceramic sheet 34 collects the charge signal generated by the stress cone 33 due to mechanical vibration or deformation (sensitivity 5 pC / N), quantifies the axial pressure fluctuation of the joint (range ±500 N); Through the wavelet packet decomposition algorithm of the NPU coprocessor, it distinguishes construction impact (>100 Hz high-frequency component) from long-term deformation (<10 Hz low-frequency component), and the positioning accuracy reaches ±2 cm;

[0051] The distributed optical fiber 36 (connected to the OTDR module of the edge computing module 25 at both ends, refreshing the full-length strain-temperature joint distribution map every 30 seconds;

[0052] Based on the Brillouin scattering effect of the Φ0.25 mm bend-resistant optical fiber, the distributed optical fiber 36 measures the axial strain distribution (resolution 1 με) and temperature field (accuracy ±0.3 °C) of the main insulation layer 3; The spiral layout with a pitch of 10 - 15 mm realizes a spatial resolution ≤ 5 mm, and can identify strain anomalies caused by microcracks of 0.1 mm level, greatly improving the detection efficiency compared with traditional point sensors;

[0053] The electrodes of the micro capacitive probe 35 are in direct contact with the carbon nanotube / EPDM material of the inner semi-conductive layer 2, and the signal is transmitted to the differential amplifier circuit of the edge computing module 25 through a shielded cable;

[0054] The micro capacitive probe 35 monitors the electric field distortion of the inner semi-conductive layer 2 (sensitivity 0.1 kV / mm 2) Locate the regions of electric field concentration caused by interface peeling or contamination; The equiangular distribution (60° interval) of six groups of probes combined with the inverse problem solving algorithm of the NPU can reconstruct the three-dimensional electric field distribution with an error ≤ 5%, and can identify partial discharge points with a diameter of more than 3 mm;

[0055] The humidity sensor 23 collects data every 10 minutes. When the humidity > 60%RH, it starts high-frequency sampling (1Hz) and uploads the positioning information to the operation and maintenance terminal through the UWB module;

[0056] The humidity sensor 23 detects the humidity jump caused by the micro-crack seepage of the waterproof layer 22 (range 0 - 100%RH, accuracy ±2%RH) and triggers the seal failure warning; Adopting MEMS capacitive humidity sensing technology, the response time ≤ 3s. After fusing with the strain data of the distributed optical fiber 36, it can distinguish environmental humidity interference from real leakage (false alarm rate < 1%);

[0057] NPU coprocessor: Deploy a lightweight convolutional neural network (CNN) for electric field distortion image recognition and strain pattern classification (inference delay < 50ms);

[0058] STM32H743VIT6: Runs the FreeRTOS real-time system to process the time series analysis and threshold judgment of the raw sensor data;

[0059] ubloxZED-F9P positioning module: Provides centimeter-level positioning accuracy (RTK mode) and marks the GPS coordinates of the fault point (error ±10cm).

[0060] Communication link of the dual-frequency anti-metal RFID tag 24:

[0061] High-frequency band (13.56 MHz): Used for near-field identity recognition (reading distance 10 cm), interacts with the NFC module of the AR operation and maintenance terminal to quickly retrieve the historical maintenance records of the joint;

[0062] Ultra-high frequency band (920 - 925 MHz): Transmits the compressed sensing data packets to the Internet of Things platform (maximum transmission rate 2Mbps, anti-metal performance > 30dBm);

[0063] UWB module (3.5 - 6.5 GHz): Achieves precise positioning of the fault point in a complex electromagnetic environment (TOA ranging accuracy ±15cm), guiding the operation and maintenance personnel directly to the defect location.

[0064] The lithium thionyl chloride battery 26 uses the dynamic voltage regulation (DVS) technology of STM32 to reduce the power consumption of the MCU to 10 μA in the standby mode. The NPU is only activated during data burst periods. Based on the Peukert equation, the battery capacity attenuation is modeled, and combined with the temperature compensation algorithm (-40°C to 85°C), it ensures maintenance-free operation for more than 5 years. When the battery voltage is detected to be <2.8 V, non-core sensors (such as distributed optical fibers) are turned off, and communication modules and positioning functions are preferentially maintained.

[0065] Algorithm flow:

[0066] Data preprocessing: Perform moving average filtering and outlier removal on time series data such as temperature, humidity, and vibration.

[0067] Feature extraction: Use wavelet transform to extract the frequency domain features of vibration signals, and use principal component analysis (PCA) to reduce the dimensionality of electric field distribution data.

[0068] Condition assessment: Generate a health index (HI) based on a fuzzy logic rule base (12 types of fault modes). When HI < 70%, a maintenance work order is triggered.

[0069] Thermo-mechanical-electrical coupling diagnosis: The temperature sensor 32 and the distributed optical fiber 36 jointly invert the thermal resistance at the conductor-insulator interface (error < 5%), and the piezoelectric ceramic sheet 34 and the micro-capacitance probe 35 cooperate to identify the electric field distortion induced by mechanical deformation.

[0070] Spatio-temporal correlation analysis: The edge computing module 25 establishes a spatio-temporal matrix of sensor data (timestamp synchronization accuracy ±1 ms), and converts one-dimensional signals into two-dimensional fault feature maps through the Gramian angular field (GAF), improving the CNN classification accuracy to 99.2%.

[0071] Early warning stage: After the humidity sensor 23 detects water seepage, the RFID tag 24 broadcasts an alarm signal through UWB, and the AR terminal displays an animation of the leakage path.

[0072] Location stage: The data of the distributed optical fiber 36 and the piezoelectric ceramic sheet 34 are fused to generate the three-dimensional coordinates of the crack and navigate to the fault point.

[0073] Decision-making stage: The edge computing module 25 calls the knowledge graph to recommend maintenance solutions (such as replacing the sealing ring or strengthening the waterproof layer), and pushes spare part inventory information to the operation and maintenance terminal.

[0074] Working principle: When the cable is operating normally, the heat dissipation layer 9 dissipates heat passively through the high heat radiation rate of the aluminum alloy material; when the temperature rise threshold is detected, the axial flow fan 15 starts to enhance convection, and the heat dissipation efficiency is greatly improved compared with the pure passive solution; after starting for a certain period of time, the two-way axial flow fan 15 blows back, and the brush wire 31 is driven by the waterproof motor 29 to clean the filter screen 14. The self-cleaning mechanism can remove more than 90% of the filter screen dust, ensuring that the annual heat dissipation efficiency decay ≤ 5%, effectively reducing the frequency of manual cleaning; when the cable suddenly short-circuits or is overloaded, the PCM ring 16 quickly absorbs the Joule heat (phase change latent heat ≥ 180 kJ / kg) transmitted by the conductor connection layer 1 through solid-liquid phase change. The graphene heat conduction sheet 18 evenly diffuses the heat to the adjacent heat conduction rings 17, and the copper wire mesh 19 dissipates heat through radiation assistance, reducing the temperature rise rate of the main insulation layer 3 by more than 60%, effectively avoiding XLPE insulation carbonization; the temperature sensor 32 is in direct contact with the silver-plated copper crimping tube of the conductor connection layer 1, with a sampling frequency of 1 kHz. The data is converted into a temperature gradient map through the ADC module of STM32H743VIT6. The temperature sensor 32 monitors the contact resistance temperature rise of the conductor connection layer 1 in real time, captures local overheating caused by loosening or corrosion, and eliminates electromagnetic interference through the Kalman filtering algorithm of the edge computing module 25, making the temperature rise detection response time ≤ 200 ms, which is greatly improved compared with the traditional solution;

[0075] The gas sensor 27 starts a gas sampling cycle every 5 minutes and switches to continuous monitoring mode under abnormal conditions. The data is uploaded to the cloud database through the Bluetooth 5.2 module: The gas sensor 27 detects characteristic gases such as CO, H2, and C2H2 generated by the thermal decomposition of insulating materials (detection limit ≤ 10 ppm) to identify early partial discharge or overheating defects; using the nano-catalytic sensitive film technology, the gas identification accuracy rate ≥ 98%, combined with the LSTM time series analysis of the edge computing module 25, to achieve early warning of insulation deterioration 6 - 8 hours in advance;

[0076] The piezoelectric ceramic sheet 34 is conformally attached to the silicone rubber matrix of the stress cone 33, and the signal is conditioned by the charge amplifier and then input into the DSP core of STM32 for time-frequency domain feature extraction;

[0077] The piezoelectric ceramic sheet 34 collects the charge signal (sensitivity 5 pC / N) generated by the stress cone 33 due to mechanical vibration or deformation, and quantifies the axial pressure fluctuation of the joint (range ± 500 N); through the wavelet packet decomposition algorithm of the NPU coprocessor, it distinguishes construction impact (> 100 Hz high-frequency component) from long-term deformation (< 10 Hz low-frequency component), and the positioning accuracy reaches ± 2 cm;

[0078] The distributed optical fiber 36 (connected to the OTDR module of the edge computing module 25 at both ends, refreshing the full-length strain-temperature joint distribution map every 30 seconds;

[0079] The distributed optical fiber 36 measures the axial strain distribution (resolution 1 με) and temperature field (accuracy ±0.3 °C) of the main insulation layer 3 based on the Brillouin scattering effect of Φ0.25 mm bend-resistant optical fiber; the spiral layout with a pitch of 10 - 15 mm achieves a spatial resolution of ≤5 mm, can identify strain anomalies caused by microcracks at the 0.1 mm level, and greatly improves the detection efficiency compared with traditional point sensors;

[0080] The electrodes of the micro capacitive probe 35 are in direct contact with the carbon nanotube / EPDM material of the inner semi-conductive layer 2, and the signal is transmitted to the differential amplifier circuit of the edge computing module 25 through a shielded cable;

[0081] The micro capacitive probe 35 monitors the electric field distortion of the inner semi-conductive layer 2 (sensitivity 0.1 kV / mm 2 ), and locates the electric field concentration area caused by interface peeling or contamination; the equal-angle distribution (60° interval) of six groups of probes combined with the inverse problem solving algorithm of the NPU reconstructs the three-dimensional electric field distribution error of ≤5%, and can identify partial discharge points with a diameter of more than 3 mm;

[0082] The humidity sensor 23 collects data every 10 minutes. When the humidity > 60% RH, it starts high-frequency sampling (1 Hz) and uploads the positioning information to the operation and maintenance terminal through the UWB module;

[0083] The humidity sensor 23 detects the humidity jump caused by the water seepage of the microcracks in the waterproof layer 22 (measurement range 0 - 100% RH, accuracy ±2% RH), and triggers the seal failure warning; adopting MEMS capacitive humidity sensing technology, the response time is ≤3 s. After fusing with the strain data of the distributed optical fiber 36, it can distinguish environmental humidity interference from real leakage (false alarm rate < 1%);

[0084] NPU coprocessor: Deploy a lightweight convolutional neural network (CNN) for electric field distortion image recognition and strain pattern classification (inference delay < 50 ms);

[0085] STM32H743VIT6: Runs the FreeRTOS real-time system to process the time series analysis and threshold judgment of the original sensor data;

[0086] ubloxZED-F9P positioning module: Provides centimeter-level positioning accuracy (RTK mode) and marks the GPS coordinates of the fault point (error ±10 cm).

[0087] Communication link of the dual-frequency anti-metal RFID tag 24:

[0088] High-frequency band (13.56 MHz): Used for near-field identity recognition (reading distance 10 cm), interacts with the NFC module of the AR operation and maintenance terminal, and quickly retrieves the historical maintenance records of the joint;

[0089] Ultra-high frequency band (920 - 925 MHz): Transmit the compressed sensing data packets to the Internet of Things platform (maximum transmission rate 2 Mbps, anti-metal performance > 30 dBm);

[0090] UWB module (3.5 - 6.5 GHz): Achieve precise fault point location in complex electromagnetic environments (TOA ranging accuracy ±15 cm), guiding maintenance personnel directly to the defect location.

[0091] The lithium thionyl chloride battery 26 uses the dynamic voltage regulation (DVS) technology of STM32 to reduce the power consumption of the MCU to 10 μA in standby mode. The NPU is only activated during data burst periods. Based on the Peukert equation to model the battery capacity attenuation, combined with the temperature compensation algorithm (-40°C to 85°C), it ensures maintenance-free operation for more than 5 years. When the battery voltage is detected to be < 2.8V, non-core sensors (such as distributed optical fibers) are turned off, and communication modules and positioning functions are preferentially maintained;

[0092] Algorithm process:

[0093] Data preprocessing: Perform moving average filtering and outlier removal on time series data such as temperature, humidity, and vibration;

[0094] Feature extraction: Use wavelet transform to extract the frequency domain features of vibration signals, and use principal component analysis (PCA) to reduce the dimensionality of electric field distribution data;

[0095] Condition assessment: Generate a health index (HI) based on a fuzzy logic rule base (12 types of fault modes). When HI < 70%, a maintenance work order is triggered;

[0096] Thermal-mechanical-electrical coupling diagnosis: The temperature sensor 32 and the distributed optical fiber 36 jointly invert the thermal resistance of the conductor-insulator interface (error < 5%), and the piezoelectric ceramic sheet 34 and the micro-capacitance probe 35 cooperate to identify the electric field distortion induced by mechanical deformation;

[0097] Spatio-temporal correlation analysis: The edge computing module 25 establishes a spatio-temporal matrix of sensor data (timestamp synchronization accuracy ±1 ms), converts one-dimensional signals into two-dimensional fault feature maps through Gramian Angular Field (GAF), and improves the CNN classification accuracy to 99.2%.

[0098] Early warning stage: After the humidity sensor 23 detects water seepage, the RFID tag 24 broadcasts an alarm signal through UWB, and the AR terminal displays an animation of the leakage path;

[0099] Location stage: The data of the distributed optical fiber 36 and the piezoelectric ceramic sheet 34 are fused to generate the three-dimensional coordinates of the crack and navigate to the fault point;

[0100] Decision-making stage: The edge computing module 25 invokes the knowledge graph to recommend maintenance solutions (such as replacing the sealing ring or strengthening the waterproof layer) and pushes the spare parts inventory information to the operation and maintenance terminal.

[0101] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-functional intermediate joint capable of connecting cables, characterized in that: It includes a joint body, an operation and maintenance handheld terminal based on RFID and GPS, and an Internet of Things platform. The joint body is fixedly connected to the cable joint. The joint body includes a conductor connection layer (1), an inner semiconductive layer (2), a main insulation layer (3), a heat conduction layer (4), an outer semiconductive layer (5), a metal shielding layer (6), a protective layer (7), an outer sheath layer (8), and an external heat dissipation structure for heat dissipation. The external heat dissipation structure includes a heat dissipation layer (9), an air outlet ring pipe (11), a blowing pipe (12), a two-way axial flow fan (15), and a self-cleaning mechanism. The air outlet ring pipe (11) and the heat dissipation layer (9) are arranged on the outer wall of the outer sheath layer (8) in sequence from front to back. The blowing pipe (12) is arranged on the side wall of the air outlet ring pipe (11). The two-way axial flow fan (15) is arranged inside the blowing pipe (12). The heat conduction layer (4) is composed of multiple groups of PCM rings (16) and multiple groups of heat conduction rings (17) that are axially spaced apart. The multiple groups of PCM rings (16) and heat conduction rings (17) are both arranged on the outer wall of the main insulation layer (3). The PCM ring (16) is a paraffin-based phase change material encapsulated in a ring-shaped copper-graphene composite shell. The heat conduction ring (17) is a ring-shaped graphene-copper heat conduction bridge. A waterproof chamber (10) is arranged on the outer wall of the outer sheath layer (8) and in front of the air outlet ring pipe (11). Inside the waterproof chamber (10), there are arranged a dual-frequency anti-metal RFID tag (24), an edge computing module (25), and a lithium thionyl chloride battery (26) for connecting the joint to the operation and maintenance handheld terminal and the Internet of Things platform. On the joint body, there are arranged a gas sensor (27), a temperature sensor (32), a piezoelectric ceramic sheet (34), a micro capacitive probe (35), a distributed optical fiber (36), and a humidity sensor (23) for real-time monitoring of multi-physical quantity coupling fields of multi-dimensional parameters of the joint body. The edge computing module (25) is used to fuse and process multi-source heterogeneous data to generate the health status information of the joint body.

2. The multi-functional intermediate joint capable of connecting a cable according to claim 1, characterized in that: The heat dissipation layer (9) is composed of an inner heat dissipation pipe (901), a honeycomb support structure (902), and an outer heat dissipation pipe (903) arranged in sequence from the inside to the outside. The inner heat dissipation pipe (901), the honeycomb support structure (902), and the outer heat dissipation pipe (903) are all made of aluminum alloy. A plurality of groups of hexagonal honeycomb holes are arranged inside the honeycomb support structure (902). The plurality of groups of hexagonal honeycomb holes penetrate through the front and rear ends of the heat dissipation layer (9) to form an air duct. The outer diameter of the air outlet ring pipe (11) is smaller than the inner diameter of the outer heat dissipation pipe (903) and larger than the outer diameter of the inner heat dissipation pipe (901). An air outlet cavity (1101) is arranged inside the air outlet ring pipe (11). An air outlet (1102) is arranged at one end of the air outlet cavity (1101) facing the heat dissipation layer (9). The air outlet (1102) is opposite to the air duct. One end of the air blowing pipe (12) facing the air outlet ring pipe (11) communicates with the inside of the air outlet cavity (1101). A filter plate (13) is detachably connected to the end of the air blowing pipe (from which the air outlet ring pipe (11) is far away). A filter net (14) is arranged on the inner side wall of the filter plate (13). The filter net (14) is cleaned by a two-way axial flow fan (15) and a self-cleaning mechanism; The self-cleaning mechanism includes a waterproof motor (29), a rotating rod (30), and a plurality of groups of brush filaments (31). The waterproof motor (29) is fixedly connected to the inner side wall of the air blowing pipe (12) through a fixed bracket (28). The rotating rod (30) is fixedly connected to the end of the protruding shaft of the waterproof motor (29). The middle position in the length direction of the rotating rod (30) is connected to the end of the protruding shaft of the waterproof motor (29), and the axis of the rotating rod (30) is perpendicular to the axis of the protruding shaft of the waterproof motor (29). A plurality of groups of brush filaments (31) are all fixedly connected to the side of the rotating rod (30) away from the waterproof motor (29). The sides of the plurality of groups of brush filaments (31) away from the rotating rod (30) are all abutted against the side of the filter net (14) facing the inside of the air blowing pipe (12); The two frequencies of the dual-frequency anti-metal RFID tag (24) are the high-frequency band and the ultra-high-frequency band. The dual-frequency anti-metal RFID tag (24) is built-in with a UWB module. The edge computing module (25) consists of an NPU co-processor, a low-power Bluetooth 5.2 module, an STM32H743VIT6, an NPU acceleration chip, and an ublox ZED-F9P positioning module; A graphene heat conduction sheet (18) is arranged on the inner side wall of the PCM ring (16). The graphene heat conduction sheet (18) covers 100% of the area of the inner side wall of the PCM ring (16). A copper wire mesh (19) is arranged on the circumferential outer wall of the PCM ring (16). The copper wire mesh (19) covers 80% of the area of the outer wall of the PCM ring (16). The wire diameter of the copper wire in the copper wire mesh (19) is 0.2 mm.

3. The multifunctional intermediate joint capable of connecting cables according to claim 2, characterized in that: The conductor connection layer (1) is a silver-plated copper compression joint pipe. The conductor connection layer (1) is connected at the cable joint. A groove is arranged on the outer wall of the conductor connection layer (1) and near the middle position. The temperature sensor (32) is arranged inside the groove.

4. The multifunctional intermediate joint capable of connecting a cable according to claim 3, characterized in that: The inner semiconductive layer (2) is EPDM doped with carbon nanotubes. The micro capacitive probe (35) is arranged on the inner wall of the inner semiconductive layer (2). There are six groups of the micro capacitive probes (35), and the six groups of the micro capacitive probes (35) are evenly distributed in a circumferential equidistant manner with the axis of the inner semiconductive layer (2) as the center.

5. A multi-functional intermediate joint capable of connecting cables according to claim 4, characterized in that: The main insulation layer (3) is XLPE modified by nano-aluminum trioxide. The distributed optical fiber (36) is spirally wound around the inner side wall of the main insulation layer (3). The distributed optical fiber (36) uses a Φ0.25mm bend-resistant optical fiber, and the pitch of the spiral winding of the distributed optical fiber (36) is 10 - 15mm.

6. The multi-functional intermediate joint capable of connecting a cable according to claim 5, characterized in that: The outer semiconductive layer (5) is conductive silicone rubber. Stress cones (33) are arranged at both circumferential ends of the outer semiconductive layer (5). There are two groups of piezoelectric ceramic sheets (34), and the two groups of piezoelectric ceramic sheets (34) are respectively arranged on the inner side walls of a group of stress cones (33).

7. The multi-functional intermediate joint capable of connecting cables according to claim 6, wherein: The metal shielding layer (6) is composed of a copper braid and a corrugated aluminum tube distributed inside and outside. Rogowski coils and induction power-taking coils are arranged on the outer wall of the corrugated aluminum tube. The Rogowski coils and the induction power-taking coils are shielded by a permalloy layer with a thickness of 0.1mm.

8. The multifunctional intermediate joint capable of connecting a cable according to claim 7, wherein: The protective layer (7) is composed of a buffer layer (20), a flame retardant layer (21), and a waterproof layer (22) distributed inside and outside. The buffer layer (20) is silicone rubber foam. The flame retardant layer (21) is ceramicized silicone rubber containing microcapsules, and the microcapsules are internally encapsulated with an APP / PER / MEL system flame retardant. The waterproof layer (22) is fluororubber. The humidity sensor (23) is arranged on the inner wall of the waterproof layer (22).

9. The multi-functional intermediate joint capable of connecting cables according to claim 8, wherein: The outer sheath layer (8) is polyurethane with an anti-ultraviolet grade of UV-A.

10. A multifunctional intermediate joint capable of connecting a cable according to claim 9, characterized in that: The gas sensor (27) is arranged on the upper wall of the waterproof chamber (10).

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