Intermediate joint structure of waterproof cable

Abstract

The invention provides a waterproof cable intermediate joint structure, and relates to the technical field of cable intermediate joints, the waterproof cable intermediate joint structure comprises stress cones, the stress cones are installed at cable joints through compression devices, the parts, extending out of the stress cones, of the two cable joints are connected through a connecting sleeve, and the connecting sleeve and the two stress cones are sleeved with a protective copper shell. Epoxy resin is filled between the protection copper shell and the stress cone, one end of the protection copper shell contacted with the cable sheath is provided with a waterproof layer, and an intelligent monitoring system is integrated in the intermediate joint. The high waterproof performance is achieved through cooperation of epoxy resin filling and the waterproof layer, moisture is effectively blocked to prevent the interior of the connector from being damped and broken down, the power transmission safety is improved, the copper shell is protected to provide mechanical support, the external force impact resistance of the connector is enhanced, and the connector is suitable for the complex environment; potential faults can be warned in advance, the manual inspection cost is reduced, and the operation and maintenance efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of cable joints, and specifically relates to a waterproof cable joint structure. Background Technology

[0002] Waterproof cable joints are critical components in power transmission systems, and their performance directly affects the safety and reliability of power grid operation. As power grid construction becomes increasingly complex and environmentally diverse, higher demands are placed on the waterproof sealing, mechanical strength, and condition monitoring capabilities of cable joints. However, existing waterproof cable joint technologies generally suffer from the following defects: (1) Insufficient reliability of waterproof sealing: Traditional waterproof structures often use a single sealing material (such as ordinary rubber tape wrapping). After long-term operation, cracks are easily caused by material aging or environmental stress, leading to moisture intrusion into the joint and causing insulation breakdown fault. (2) Limited mechanical protection performance: Some intermediate joints rely only on plastic or thin metal shells as protective layers, which are weak in resisting external impacts (such as soil extrusion and construction collisions), which may lead to loosening of internal connections or damage to the insulation layer. Especially under complex geological conditions, the risk of mechanical failure increases significantly. (3) Lack of condition monitoring capability: Existing joints generally lack real-time monitoring means, and cannot dynamically sense abnormal conditions such as internal heating, moisture intrusion or mechanical vibration. They rely on manual periodic inspections, making it difficult to detect early defects in advance, which can easily lead to unplanned power outages or even major accidents. Summary of the Invention

[0003] The present invention provides a waterproof cable intermediate joint structure to solve at least one of the technical problems mentioned above.

[0004] To solve the above-mentioned technical problems, the present invention discloses a waterproof cable intermediate joint structure, including a stress cone. The stress cone is installed at the cable joint by a compression device. The portions of the two cable joints extending out of the stress cone are connected by a connecting sleeve. A protective copper shell is provided over the connecting sleeve and the two stress cones. Epoxy resin is filled between the protective copper shell and the stress cone. A waterproof layer is provided at the end of the protective copper shell that contacts the cable sheath. An intelligent monitoring system is integrated inside the intermediate joint.

[0005] Preferably, the intelligent monitoring system includes: The temperature sensing module includes a thin-film platinum resistance sensor that fits into the connecting sleeve and several distributed fiber optic temperature measurement units on the outside of the cable insulation layer. The thin-film platinum resistance sensor and the distributed fiber optic temperature measurement units are used to collect the real-time temperature of the conductor contact area of ​​the connecting sleeve and the temperature of the outside of the cable insulation layer, respectively. The humidity sensing module is embedded at the interface between the protective copper shell and the epoxy resin to collect the real-time relative humidity of the interface between the copper shell and the epoxy resin inside the connector. The vibration acceleration sensor module is attached to the outer surface of the protective copper shell and is used to collect vibration acceleration signals from the external environment of the cable connector. The joint health assessment module is used to obtain the health status of waterproof cable intermediate joints based on the detection values ​​of the temperature sensing module, humidity sensing module, and vibration acceleration sensing module.

[0006] Preferably, the connector health assessment module includes: The data preprocessing submodule is used to perform noise reduction filtering and data standardization processing on the signals collected by the temperature sensing module, humidity sensing module and vibration acceleration sensing module. The feature parameter extraction submodule is used to obtain the effective values ​​of the connecting sleeve temperature rise rate, insulation layer temperature gradient, interface humidity change rate, and vibration acceleration based on the data processed by the data preprocessing submodule. The condition assessment model submodule is used to calculate the condition health of waterproof cable intermediate joints based on the temperature rise rate of the connecting sleeve, the temperature gradient of the insulation layer, the rate of change of interface humidity, and the effective value of vibration acceleration, and to assess the condition of the waterproof cable intermediate joints based on the calculated condition health value.

[0007] Preferably, the temperature rise rate of the connecting sleeve is calculated as follows: ;in, To determine the temperature rise rate of the connecting sleeve, This represents the real-time temperature of the contact area between the conductors of the connecting sleeve and the current temperature, i.e., the current detection value of the thin-film platinum resistance sensor. The real-time temperature of the contact area between the conductors of the connecting sleeve was measured seconds ago, which is the value detected by the thin-film platinum resistance sensor seconds ago, representing the time interval of seconds. The temperature gradient of the insulation layer is calculated as follows: ;in, For the temperature gradient of the insulation layer, This refers to the maximum temperature collected by all distributed fiber optic temperature sensing units on the outer side of the cable insulation layer. This refers to the minimum temperature collected by all distributed fiber optic temperature measurement units on the outer side of the cable insulation layer. The distance between the largest and smallest distributed fiber optic temperature measurement units on the surface of the cable insulation layer; The rate of change of interface humidity is calculated as follows: ; The rate of change of interface humidity. This represents the real-time relative humidity at the interface between the protective copper shell inside the connector and the epoxy resin seal, i.e., the current detection value of the humidity sensing module. The real-time relative humidity of the interface between the protective copper shell inside the connector and the epoxy resin seal is the value detected by the humidity sensing module, which represents the time interval in seconds. The effective value of vibration acceleration is calculated as follows: ;in, This is the effective value of vibration acceleration. This represents the total number of sampling points in a single sampling session. To protect the vibration acceleration value of the vibration accelerometer at the i-th sampling point on the outer surface of the copper shell; The health status of waterproof cable joints is calculated as follows: ;in, To assess the health and condition of the waterproof cable joint. The coefficient representing the influence of heat loss on the degree of heat generation. The coefficient representing the influence of the degree of abnormality in the insulation material. This represents the influence coefficient on the degree of failure of the waterproof layer.

[0008] Preferably, the stress cone is a semi-conductive silicone rubber stress cone, made of silicone rubber material, used to improve the electric field distribution at the cable shield cut-off point; The connecting sleeve is made of copper or aluminum alloy and is fixedly connected to the part of the two cable connectors that protrude from the stress cone by crimping. Conductive adhesive is applied to the connection to reduce contact resistance.

[0009] Preferably, the compression device is a detachable metal clamp structure, including clamp one, clamp two and several connecting parts. Clamp one is used to connect with the stress cone to provide constant radial pressure to the stress cone. Clamp two is used to connect with the cable joint to provide constant radial pressure to the cable joint. The connecting parts are used to connect clamp one and clamp two.

[0010] Preferably, the waterproof layer comprises multiple layers of elastic waterproof self-adhesive tape and sealant. The elastic waterproof self-adhesive tape is wrapped around the end that protects the copper shell in contact with the cable sheath, and the sealant fills the gap between the elastic waterproof self-adhesive tape and the cable sheath.

[0011] Preferably, a semi-conductive self-adhesive tape is provided between the two stress cones to ensure uniform electric field distribution.

[0012] Preferably, the epoxy resin is a composite system of low molecular weight epoxy resin, phenyl silicone resin, and amino silicone resin, and the dielectric constant after curing is ≥3.8.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves high waterproof performance through epoxy resin filling and a waterproof layer, effectively blocking moisture to prevent internal moisture breakdown of the joint, improving power transmission safety, protecting the copper shell and providing mechanical support, enhancing the joint's resistance to external impacts, making it suitable for complex environments, and using an intelligent monitoring system to monitor the joint's operating status in real time, providing early warning of potential faults, reducing manual inspection costs and improving maintenance efficiency, optimizing the electric field distribution with a stress cone to reduce the risk of partial discharge, extending the cable joint's service life, and using a modular structure design for easy installation and maintenance, adapting to the connection needs of cables of different specifications. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the waterproof cable intermediate joint of the present invention.

[0015] In the diagram: 1. Stress cone; 2. Compression device; 20. Fastener 1; 21. Fastener 2; 22. Connector; 3. Connecting sleeve; 4. Protective copper shell; 5. Epoxy resin; 6. Waterproof layer; 7. Semi-conductive self-adhesive tape. Detailed Implementation

[0016] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0017] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0018] The present invention provides the following embodiments. Example 1 This invention provides a waterproof cable intermediate joint structure, such as... Figure 1As shown, it includes a stress cone 1, which is installed at the cable joint via a compression device 2. The portions of the two cable joints extending out of the stress cone 1 are connected by a connecting sleeve 3. A protective copper shell 4 is provided over the connecting sleeve 3 and the two stress cones 1. Epoxy resin 5 is filled between the protective copper shell 4 and the stress cone 1. A waterproof layer 6 is provided at the end of the protective copper shell 4 that contacts the cable sheath. An intelligent monitoring system is integrated inside the intermediate joint.

[0019] The working principle and beneficial effects of the above technical solution are as follows: The stress cone 1 of the present invention is fixed at the cable joint by the compression device 2. Its semi-conductive silicone rubber material can improve the electric field distribution at the cable shield cut-off point and avoid local electric field concentration. The parts of the two cable joints that extend out of the stress cone 1 are connected by the connecting sleeve 3. The connection is coated with conductive glue to reduce the contact resistance. The protective copper shell 4 is sleeved on the outside of the connecting sleeve 3 and the stress cone 1 to form a mechanical protective layer. The interior is filled with epoxy resin 5 to achieve insulation and sealing. The waterproof layer 6 wraps and protects the connection between the copper shell and the cable sheath to prevent moisture intrusion. The intelligent monitoring system is integrated inside the intermediate joint to collect data such as temperature, humidity and vibration in real time and assess the health status of the joint. This invention achieves high waterproof performance by filling with epoxy resin 5 and combining it with a waterproof layer 6, effectively blocking moisture to prevent internal moisture breakdown of the joint, improving power transmission safety, protecting the copper shell 4 by providing mechanical support, enhancing the joint's resistance to external impacts, making it suitable for complex environments, and using an intelligent monitoring system to monitor the joint's operating status in real time, providing early warning of potential faults, reducing manual inspection costs and improving maintenance efficiency, and using a stress cone 1 to optimize the electric field distribution to reduce the risk of partial discharge and extend the service life of the cable joint, while the modular structure design facilitates installation and maintenance and adapts to the connection needs of cables of different specifications.

[0020] Example 2 Based on Example 1, the intelligent monitoring system includes: The temperature sensing module includes a thin-film platinum resistance sensor attached to the connecting sleeve 3 and several distributed fiber optic temperature measurement units on the outside of the cable insulation layer. The thin-film platinum resistance sensor and the distributed fiber optic temperature measurement units are used to collect the real-time temperature of the conductor contact area of ​​the connecting sleeve 3 and the temperature of the outside of the cable insulation layer, respectively. Among them, the real-time temperature of the conductor contact area of ​​the connecting sleeve 3 is used to reflect the electrical contact status and Joule loss heating of the conductive connection part of the cable joint, and the temperature distribution gradient on the surface of the cable insulation layer is used to monitor the thermal aging of the insulation material and the abnormal temperature rise caused by partial discharge. A humidity sensing module is embedded at the interface between the protective copper shell 4 and the epoxy resin 5, and is used to collect the real-time relative humidity of the sealing interface between the protective copper shell 4 and the epoxy resin 5 inside the connector. Among them, the real-time relative humidity of the sealing interface between the internal protective copper shell 4 and the epoxy resin 5 is used to monitor the moisture intrusion caused by the failure of the waterproof layer and the degree of moisture absorption of the epoxy resin insulation system. The vibration acceleration sensor module is attached to the outer surface of the protective copper shell 4 and is used to collect vibration acceleration signals from the external environment of the cable connector. Among them, the external environmental vibration signal of the cable joint is used to evaluate the impact of mechanical vibration on the reliability of the connecting sleeve crimping and the protective copper shell sealing structure. The joint health assessment module is used to obtain the health status of waterproof cable intermediate joints based on the detection values ​​of the temperature sensing module, humidity sensing module, and vibration acceleration sensing module.

[0021] The working principle and beneficial effects of the above technical solution are as follows: The temperature sensing module of this invention collects the real-time temperature of the conductor contact area of ​​the connecting sleeve 3 through a thin-film platinum resistance sensor attached to the connecting sleeve 3, reflecting the heating of the contact resistance. The distributed optical fiber temperature measurement unit monitors the temperature on the outside of the cable insulation layer. The humidity sensing module is embedded at the interface between the protective copper shell 4 and the epoxy resin 5, and monitors the relative humidity of the sealing interface between the protective copper shell 4 and the epoxy resin 5 in real time, judging whether the waterproof layer 6 has failed or the epoxy resin 5 has absorbed moisture. The vibration acceleration sensing module is attached to the outer surface of the protective copper shell 4, collects the vibration acceleration signal of the external environment of the cable joint, and evaluates the impact of mechanical vibration on the connection structure. The joint health assessment module calculates the health status of the waterproof cable intermediate joint based on the detection values ​​of the temperature sensing module, humidity sensing module and vibration acceleration sensing module through an algorithm, and realizes fault prediction. This invention provides multi-dimensional sensing and monitoring covering various parameters including electrical, mechanical, and environmental parameters, ensuring comprehensive condition assessment. Temperature monitoring can promptly detect overheating faults caused by poor contact of the connecting sleeve 3, preventing fires caused by Joule losses. Humidity monitoring enables dynamic evaluation of the performance of the waterproof layer 6, providing early warning of moisture intrusion to prevent the deterioration of the epoxy resin 5 insulation. Vibration monitoring can identify loosening of the connecting sleeve 3 caused by mechanical vibration or fatigue of the protective copper shell 4 sealing structure, adapting to scenarios such as industrial vibration environments.

[0022] Example 3 Based on Example 2, the connector health assessment module includes: The data preprocessing submodule is used to perform noise reduction filtering and data standardization processing on the signals collected by the temperature sensing module, humidity sensing module and vibration acceleration sensing module. The feature parameter extraction submodule is used to obtain the effective values ​​of the connecting sleeve temperature rise rate, insulation layer temperature gradient, interface humidity change rate, and vibration acceleration based on the data processed by the data preprocessing submodule. The condition assessment model submodule is used to calculate the condition health of waterproof cable intermediate joints based on the temperature rise rate of the connecting sleeve, the temperature gradient of the insulation layer, the rate of change of interface humidity, and the effective value of vibration acceleration, and to assess the condition of the waterproof cable intermediate joints based on the calculated condition health value.

[0023] Preferably, the temperature rise rate of the connecting sleeve is calculated as follows: ;in, To determine the temperature rise rate of the connecting sleeve, This represents the real-time temperature of the contact area between the conductor and sleeve 3, i.e., the current detection value of the thin-film platinum resistance sensor. This is the real-time temperature of the conductor contact area of ​​the connecting sleeve 3 10 seconds ago, which is the detection value of the thin-film platinum resistance sensor 10 seconds ago. 10 represents a 10-second time interval. The temperature gradient of the insulation layer is calculated as follows: ;in, For the temperature gradient of the insulation layer, This refers to the maximum temperature collected by all distributed fiber optic temperature sensing units on the outer side of the cable insulation layer. This refers to the minimum temperature collected by all distributed fiber optic temperature measurement units on the outer side of the cable insulation layer. The distance between the largest and smallest distributed fiber optic temperature measurement units on the surface of the cable insulation layer; The rate of change of interface humidity is calculated as follows: ; The rate of change of interface humidity. This is the real-time relative humidity at the sealing interface between the internal protective copper shell 4 and the epoxy resin 5 of the connector, i.e., the current detection value of the humidity sensing module. The real-time relative humidity of the sealing interface between the internal protective copper shell 4 and the epoxy resin 5 of the connector 10 seconds ago is the detection value of the humidity sensing module 10 seconds ago, where 10 represents a 10-second time interval. The effective value of vibration acceleration is calculated as follows: ;in, This is the effective value of vibration acceleration. This represents the total number of sampling points in a single sampling session. To protect the vibration acceleration value of the vibration accelerometer at the i-th sampling point on the outer surface of the copper shell 4; The health status of waterproof cable joints is calculated as follows: ;in, To assess the health and condition of the waterproof cable joint. The coefficient representing the influence of heat loss on the degree of heat generation. The coefficient representing the influence of the degree of abnormality in the insulation material. This represents the influence coefficient on the degree of failure of the waterproof layer.

[0024] The working principle and beneficial effects of the above technical solution are as follows: The data preprocessing submodule of this invention performs noise reduction filtering and data standardization processing on the signals collected by the temperature sensing module, humidity sensing module and vibration acceleration sensing module. The feature parameter extraction submodule obtains the temperature rise rate of the connecting sleeve, the temperature gradient of the insulation layer, the rate of change of interface humidity and the effective value of vibration acceleration based on the processed data. The state assessment model submodule calculates the state health of the waterproof cable intermediate joint through formula based on the temperature rise rate of the connecting sleeve, the temperature gradient of the insulation layer, the rate of change of interface humidity and the effective value of vibration acceleration, and assesses the joint state. This invention improves the quality of the original signal through data preprocessing, ensuring the accuracy of the evaluation results. Characteristic parameters are directly associated with the core fault modes of the joint, such as heating of the connecting sleeve 3, thermal aging of the cable insulation layer, moisture intrusion at the interface between the protective copper shell 4 and the epoxy resin 5, and mechanical vibration of the protective copper shell 4, thereby improving the pertinence of fault identification. The mathematical model realizes the quantitative expression of health status, avoiding the subjectivity of manual judgment. Dynamic monitoring of parameter change rate can capture the early defect development trend. For example, an abnormal temperature rise rate of the connecting sleeve 3 indicates an increase in contact resistance. The health status of the intermediate joint of the waterproof cable is comprehensively reflected by multi-parameter weighted calculation, which is closer to the actual operating status of the joint.

[0025] Example 4 Based on Example 1, stress cone 1 is a semi-conductive silicone rubber stress cone made of silicone rubber material, used to improve the electric field distribution at the cable shield cut-off point; The connecting sleeve 3 is made of copper or aluminum alloy and is fixedly connected to the part of the two cable connectors that protrude from the stress cone 1 by crimping. Conductive adhesive is applied to the connection to reduce contact resistance.

[0026] Preferably, the waterproof layer 6 includes multiple layers of elastic waterproof self-adhesive tape and sealant. The elastic waterproof self-adhesive tape is wrapped around the end of the protective copper shell 4 that contacts the cable sheath, and the sealant fills the gap between the elastic waterproof self-adhesive tape 61 and the cable sheath.

[0027] Preferably, a semi-conductive self-adhesive tape 7 is provided between the two stress cones 1 to ensure uniform electric field distribution.

[0028] Preferably, epoxy resin 5 is a composite system of low molecular weight epoxy resin, phenyl silicone resin, and amino silicone resin, with a dielectric constant ≥3.8 after curing.

[0029] The working principle and beneficial effects of the above technical solution are as follows: The stress cone 1 of this invention is a semi-conductive silicone rubber stress cone, made of silicone rubber material. Its nonlinear conductivity can effectively disperse the electric field concentration at the cable shield break and reduce the risk of surface discharge. The connecting sleeve 3 is made of copper or aluminum alloy and is fixedly connected to the part of the two cable joints that protrude from the stress cone 1 by pressing. Conductive adhesive is applied to the connection to reduce the contact resistance. The waterproof layer 6 includes multiple layers of elastic waterproof self-adhesive tape and sealant. The elastic waterproof self-adhesive tape is wrapped around the end of the protective copper shell 4 that contacts the cable sheath. The sealant fills the gap between the elastic waterproof self-adhesive tape and the cable sheath to form a self-fusion sealing shell. A semi-conductive self-adhesive tape 7 is provided between the two stress cones 1 to ensure uniform electric field distribution. The epoxy resin 5 is a composite system of low molecular weight epoxy resin, phenyl silicone resin, and amino silicone resin. After curing, it is filled between the protective copper shell 4 and the stress cone 1 to form a high dielectric constant insulating layer. The semi-conductive silicone rubber material of the stress cone 1 in this invention has both insulation and stress relief functions, improving the electrical stability of the joint and reducing partial discharge at the cable shield cut-off point. The connecting sleeve 3, in combination with the conductive adhesive, can reduce contact resistance, reduce power loss and heat generation, and extend the life of the conductive connection. The combination of the multi-layer elastic waterproof self-adhesive tape and sealant in the waterproof layer 6 significantly improves the water immersion resistance and adapts to harsh environments such as humidity and underwater. The semi-conductive self-adhesive tape 7 connects the semi-conductive layer inside the cable to the stress cone 1, eliminating electric field abrupt changes and preventing insulation breakdown caused by surface discharge. The epoxy resin 5 composite system has a dielectric constant ≥3.8 after curing, which optimizes the electric field distribution while providing high-strength sealing, enhancing the insulation performance and mechanical strength of the joint.

[0030] Example 5 Based on Embodiment 1, the compression device 2 is a detachable metal clamp structure, including a first clamp 20, a second clamp 21, and several connecting parts 22. The first clamp 20 is used to connect with the stress cone 1 to provide constant radial pressure to the stress cone 1. The second clamp 21 is used to connect with the cable joint to provide constant radial pressure to the cable joint. The connecting parts 22 are used to connect the first clamp 20 and the second clamp 21.

[0031] The working principle and beneficial effects of the above technical solution are as follows: The compression device 2 of the present invention is a detachable metal clamp structure, including a first clamp 20, a second clamp 21 and several connecting parts 22. The first clamp 20 is connected to the outside of the stress cone 1, and the second clamp 21 is connected to the insulation layer at the cable joint. It is fastened by the connecting parts 22 to provide constant radial pressure to the stress cone 1 and the cable joint, ensuring that the stress cone 1 and the cable insulation layer are tightly fitted and avoiding air gaps. The detachable design makes it easy to adjust the position of the stress cone 1 during on-site installation to adapt to cables with different outer diameters. The constant radial pressure of the compression device 2 of this invention ensures the sealing of the interface between the stress cone 1 and the cable insulation layer, preventing moisture from entering along the interface and improving the waterproof performance of the joint. The metal clamp structure has high mechanical strength and can withstand the axial tension of the cable, preventing the connecting sleeve 3 from loosening at the cable joint. The detachable design simplifies the installation process. By adjusting the tightness of the connector 22, the positioning and fixing of the stress cone 1 can be completed quickly, improving construction efficiency. The split fasteners achieve precise pressure on the stress cone 1 and the cable insulation layer, ensuring uniform electric field distribution, reducing the risk of partial discharge, and are compatible with various cable specifications. By replacing the fasteners or adjusting the tightening force, it can adapt to the connection needs of cables of different diameters, improving the product's versatility.

[0032] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A waterproof cable intermediate joint structure, characterized in that: The joint includes a stress cone (1), which is installed at the cable joint by a compression device (2). The portions of the two cable joints that extend out of the stress cone (1) are connected by a connecting sleeve (3). The connecting sleeve (3) and the two stress cones (1) are covered with a protective copper shell (4). Epoxy resin (5) is filled between the protective copper shell (4) and the stress cone (1). A waterproof layer (6) is provided at the end of the protective copper shell (4) that contacts the cable sheath. An intelligent monitoring system is integrated inside the intermediate joint.

2. The waterproof cable intermediate joint structure according to claim 1, characterized in that: The intelligent monitoring system includes: The temperature sensing module includes a thin-film platinum resistance sensor that fits into the connecting sleeve (3) and several distributed optical fiber temperature measurement units on the outside of the cable insulation layer. The thin-film platinum resistance sensor and the distributed optical fiber temperature measurement units are used to collect the real-time temperature of the conductor contact area of ​​the connecting sleeve (3) and the temperature on the outside of the cable insulation layer, respectively. The humidity sensing module is embedded at the interface between the protective copper shell (4) and the epoxy resin (5) to collect the real-time relative humidity of the sealed interface between the copper shell (4) and the epoxy resin (5) inside the connector. The vibration acceleration sensing module is attached to the outer surface of the protective copper shell (4) and is used to collect vibration acceleration signals of the external environment of the cable joint. The joint health assessment module is used to obtain the health status of waterproof cable intermediate joints based on the detection values ​​of the temperature sensing module, humidity sensing module, and vibration acceleration sensing module.

3. The waterproof cable intermediate joint structure according to claim 2, characterized in that: The connector health assessment module includes: The data preprocessing submodule is used to perform noise reduction filtering and data standardization processing on the signals collected by the temperature sensing module, humidity sensing module and vibration acceleration sensing module. The feature parameter extraction submodule is used to obtain the effective values ​​of the connecting sleeve temperature rise rate, insulation layer temperature gradient, interface humidity change rate, and vibration acceleration based on the data processed by the data preprocessing submodule. The condition assessment model submodule is used to calculate the condition health of waterproof cable intermediate joints based on the temperature rise rate of the connecting sleeve, the temperature gradient of the insulation layer, the rate of change of interface humidity, and the effective value of vibration acceleration, and to assess the condition of the waterproof cable intermediate joints based on the calculated condition health value.

4. The waterproof cable intermediate joint structure according to claim 3, characterized in that: The temperature rise rate of the connecting sleeve is calculated as follows: ;in, To determine the temperature rise rate of the connecting sleeve, The real-time temperature of the conductor contact area of ​​the connecting sleeve (3) at the current moment is the current detection value of the thin-film platinum resistance sensor. The real-time temperature of the conductor contact area of ​​the connecting sleeve (3) 10 seconds ago is the detection value of the thin-film platinum resistance sensor 10 seconds ago, where 10 represents a 10-second time interval. The temperature gradient of the insulating layer is calculated as follows: ;in, For the temperature gradient of the insulation layer, This refers to the maximum temperature collected by all distributed fiber optic temperature sensing units on the outer side of the cable insulation layer. This refers to the minimum temperature collected by all distributed fiber optic temperature measurement units on the outer side of the cable insulation layer. The distance between the largest and smallest distributed fiber optic temperature measurement units on the surface of the cable insulation layer; The rate of change of interface humidity is calculated as follows: ; The rate of change of interface humidity. The real-time relative humidity of the sealing interface between the protective copper shell (4) inside the connector and the epoxy resin (5) is the current detection value of the humidity sensing module. The real-time relative humidity of the interface between the inner protective copper shell (4) and the epoxy resin (5) of the connector 10 seconds ago is the detection value of the humidity sensing module 10 seconds ago, where 10 represents a 10-second time interval. The effective value of the vibration acceleration is calculated as follows: ;in, This is the effective value of vibration acceleration. This represents the total number of sampling points in a single sampling session. To protect the vibration acceleration value of the vibration accelerometer at the i-th sampling point on the outer surface of the copper shell (4); The health status of the waterproof cable intermediate joint is calculated as follows: ;in, To assess the health and condition of the waterproof cable joint. The coefficient representing the influence of heat loss on the degree of heat generation. The coefficient representing the influence of the degree of abnormality in the insulation material. This represents the influence coefficient on the degree of failure of the waterproof layer.

5. The waterproof cable intermediate joint structure according to claim 1, characterized in that: The stress cone (1) is a semi-conductive silicone rubber stress cone, made of silicone rubber material, used to improve the electric field distribution at the cable shield cut-off point; The connecting sleeve (3) is made of copper or aluminum alloy and is fixedly connected to the part of the two cable connectors that extends out of the stress cone (1) by crimping. Conductive adhesive is applied to the connection to reduce contact resistance.

6. The waterproof cable intermediate joint structure according to claim 1, characterized in that: The compression device (2) is a detachable metal clamp structure, including a first clamp (20), a second clamp (21) and several connectors (22). The first clamp (20) is used to connect with the stress cone (1) and to provide a constant radial pressure to the stress cone (1). The second clamp (21) is used to connect with the cable joint and to provide a constant radial pressure to the cable joint. The connectors (22) are used to connect the first clamp (20) and the second clamp (21).

7. The waterproof cable intermediate joint structure according to claim 1, characterized in that: The waterproof layer (6) includes multiple layers of elastic waterproof self-adhesive tape and sealant. The elastic waterproof self-adhesive tape is wrapped around the end of the protective copper shell (4) that contacts the cable sheath, and the sealant fills the gap between the elastic waterproof self-adhesive tape (61) and the cable sheath.

8. The waterproof cable intermediate joint structure according to claim 1, characterized in that: A semi-conductive self-adhesive tape (7) is provided between the two stress cones (1), and the semi-conductive self-adhesive tape (7) is used to ensure uniform electric field distribution.

9. The waterproof cable intermediate joint structure according to claim 1, characterized in that: The epoxy resin (5) is a composite system of low molecular weight epoxy resin, phenyl silicone resin, and amino silicone resin, with a dielectric constant ≥3.8 after curing.

Images