Device and method for improving insulation interface performance of wrapped submarine cable molded joint

Abstract

The present invention discloses a device and method for improving the insulation interface performance of a wrapped submarine cable molded joint, belonging to the field of high-voltage DC cable insulation technology. The device and method include a plasma generator, a gas delivery module, and a transmission module. The plasma generator includes an upper dielectric module and a lower dielectric module. The upper dielectric module is provided with a high-voltage electrode, and the lower dielectric module is provided with a ground electrode. A plasma discharge channel is formed between the high-voltage electrode and the ground electrode. The gas delivery module is used to fill the plasma discharge channel with an inert gas. The transmission module includes a discharging assembly and a receiving assembly. The insulating tape passes through the plasma discharge channel from the discharging assembly and is connected to the receiving assembly. The present invention can effectively suppress the accumulation of charge on the insulation interface of the submarine cable molded joint, improve the insulation performance, and enhance the breakdown field strength. The plasma discharge technology can be applied to the insulation of full-size wrapped submarine cable molded joints to improve their insulation performance and achieve efficient, uniform, and reliable insulation recovery.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage DC cable insulation, and in particular to a device and method for improving the insulation interface performance of a wrapped submarine cable molded joint. Background Art

[0002] High-voltage direct current (HVDC) submarine cables (hereinafter referred to as "HVDC cables") are becoming increasingly important as a vital link in power grid interconnection and the "artery" for clean energy transmission. With their unique advantages of long distance, large capacity, and low loss, HVDC cables have become critical infrastructure for building new power systems and promoting the green energy transition. Long-distance HVDC cables are a key technological support for the grid-connected generation of clean energy sources such as offshore wind power.

[0003] In high-voltage DC submarine cable systems, submarine cable molded joints are core components for flexible splicing of multiple sections of submarine cables. Their insulation performance directly affects the stability and safety of the entire transmission system. Wrapped submarine cable molded joints are a common joint manufacturing method. After the conductors are connected, the insulation tape is wrapped around the joints one by one to restore the insulation. The joints are then melted and formed by synchronously heating the conductors and the heating hood, thereby restoring the insulation. However, during the melting and recovery process, due to various factors such as interface roughness, surface insulation defects, and crystallization differences, the interface area between the tape layers often produces a significant accumulation of space charge. This not only reduces the partial discharge starting voltage, but also makes the insulation interface easy to break down, seriously threatening the insulation performance of the submarine cable molded joints and the safe and stable operation of the transmission system.

[0004] Therefore, improving the insulation performance of the insulation interface of the wrapped DC submarine cable molded joint has become a technical problem that needs to be solved urgently. The existing methods for suppressing interface charge and improving performance mainly include spraying ZnO and sandpaper polishing. Although these methods can improve the insulation recovery quality to a certain extent, they all have obvious limitations. The spraying ZnO method faces problems such as low processing efficiency, high consumables, poor processing uniformity and the possible generation of decomposition by-products, which limits its wide application in actual engineering. The sandpaper polishing method is limited by the craftsmanship of on-site workers. The strength and direction of polishing are difficult to control, which can easily cause damage to the winding tape, and the consistency of the polishing effect is difficult to guarantee, making it difficult to meet the needs of large-scale industrial production.

[0005] In view of the above-mentioned deficiencies in the prior art, there is an urgent need for a new insulation improvement method for the insulation interface of a wrapped DC submarine cable molded joint. Summary of the Invention

[0006] The purpose of the present invention is to provide a device and method for improving the insulation interface performance of a wrapped submarine cable molded joint to solve the problems existing in the above-mentioned prior art, which can effectively inhibit the accumulation of charge on the insulation interface of the submarine cable molded joint, improve the insulation performance, and enhance the breakdown field strength. At the same time, it overcomes the limitations of the prior art and applies plasma discharge technology to the insulation of full-size wrapped submarine cable molded joints to improve their insulation performance and achieve efficient, uniform and reliable insulation recovery.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a device for improving the insulation interface performance of a wrapped submarine cable molded joint, comprising a plasma generator, a gas delivery module, and a transmission module. The plasma generator comprises an upper dielectric module and a lower dielectric module, the upper dielectric module being provided with a high-voltage electrode, the lower dielectric module being provided with a grounding electrode, and a plasma discharge channel being formed between the high-voltage electrode and the grounding electrode; the gas delivery module being used to fill the plasma discharge channel with an inert gas; and the transmission module comprising a discharging assembly and a receiving assembly, wherein an insulating tape passes through the plasma discharge channel from the discharging assembly and is connected to the receiving assembly.

[0009] In one embodiment, the device further comprises an insulating fixing plate and a lifting assembly, wherein the upper dielectric module is mounted on the insulating fixing plate via the lifting assembly, and the lifting assembly is used to drive the upper dielectric module to move upward and downward.

[0010] In one embodiment, the upper dielectric module is provided with an empty slot, the movable end of the lifting assembly is installed at the top of the empty slot, the high-voltage electrode is installed at the bottom of the empty slot, and the grounding electrode is installed at the bottom of the lower dielectric module.

[0011] In one embodiment, the upper dielectric module is provided with an embedded gas path, which extends along the upper dielectric module between the empty slots. The top of the upper dielectric module is provided with an air inlet, and the bottom of the upper dielectric module is provided with an air outlet, which faces the plasma discharge channel.

[0012] In one embodiment, the gas delivery module includes a gas cylinder and a flow meter, the gas cylinder stores the inert gas, the gas cylinder is connected to the gas inlet through a gas pipe, the gas pipe is provided with the flow meter, and the flow meter is used to control the flow of the inert gas.

[0013] In one embodiment, the discharging assembly includes a discharging roller and a first restraining roller, and the receiving assembly includes a gathering roller and a second restraining roller. The unprocessed insulating tape is located on the discharging roller, and the processed insulating tape is located on the gathering roller. The insulating tape passes through the first restraining roller, the plasma discharge channel, and the second restraining roller in sequence from the discharging roller to the gathering roller.

[0014] In one embodiment, the unwinding roller, the first constraining roller, the second constraining roller, and the bundling roller are all connected to independent drive motors, and the drive motors are mounted on the insulating fixing plate.

[0015] The present invention also provides a method for improving the insulation interface performance of a wrapped-type submarine cable molded joint, which uses the device for improving the insulation interface performance of a wrapped-type submarine cable molded joint as described above, comprising:

[0016] S1. Place the unprocessed insulation tape on the discharging assembly, and pull out a certain length of the insulation tape through the plasma discharge channel to the receiving assembly to complete the constraint of the insulation tape movement path;

[0017] S2. Adjust the distance between the upper dielectric module and the lower dielectric module to meet the set requirements, turn on the high-voltage electrode and the gas delivery module, and generate plasma in the plasma discharge channel;

[0018] S3, start the conveying component, use the discharging component to release the insulation tape, and use the receiving component to rewind the insulation tape;

[0019] S4. After the treatment is completed, remove the treated insulation tape.

[0020] In one embodiment, a first constraining roller in the discharging assembly and a second constraining roller in the receiving assembly are used to constrain the insulating tape, so that the insulating tape is kept moving along a set track.

[0021] In one embodiment, the following steps are further included:

[0022] S5. Weld the cable conductor, wrap the conductor shield, and wipe the insulation surface of the body;

[0023] S6. Remove the untreated insulation tape at the front and rear ends, and wrap the treated insulation tape around the surface of the conductor shield layer in turns until the defective insulation area is filled;

[0024] S7. Melt the insulation tapes wound one by one into one piece to complete the insulation restoration.

[0025] Compared with the prior art, the present invention has achieved the following technical effects:

[0026] The present invention utilizes a plasma generator to process the insulating tape under an inert gas atmosphere, and can cause active particles generated by atmospheric pressure discharge plasma to act on the surface of the insulating tape, effectively suppressing charge accumulation at the insulation interface of the submarine cable molded joint, improving insulation performance, and increasing breakdown field strength. At the same time, a transmission module is utilized to realize the discharging and receiving of the insulating tape, which can overcome the limitations of the existing technology and apply plasma discharge technology to the insulation of full-size wrapped submarine cable molded joints to improve their insulation performance and achieve efficient, uniform, and reliable insulation recovery, providing strong technical support for promoting the improvement of my country's independent innovation capabilities for high-end power equipment, supporting the large-scale grid connection of offshore wind power, and ensuring the safe and stable operation of electric energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a front view of a device for improving the insulation interface performance of a wrapped submarine cable molded joint according to an embodiment of the present invention;

[0029] Figure 2 A top view of a device for improving the insulation interface performance of a wrapped submarine cable molded joint according to an embodiment of the present invention;

[0030] Figure 3 This is a side view of a device for improving the insulation interface performance of a wrapped submarine cable molded joint according to an embodiment of the present invention;

[0031] Figure 4 Schematic diagram of the insulation preparation process of the wrapped submarine cable molded joint in an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of cutting a double-layer interlayer interface flat plate sample in an embodiment of the present invention;

[0033] Figure 6 The discharge images of the dielectric barrier discharge plasma reactor of the present invention at different voltage amplitudes, frequencies and gas flow rates;

[0034] Figure 7 This is a flow chart of a method for improving the insulation interface performance of a wrapped submarine cable molded joint according to an embodiment of the present invention;

[0035] Figure 8 The microscopic morphology images of the interfaces of the comparative examples and examples of the present invention are shown;

[0036] Figure 9The charge distribution on both sides of the interlayer interface during the 40 kV / mm high field poling for 1800 s in the comparative example and the embodiment of the present invention;

[0037] Figure 10 The DCIC-Q(t) curves of the comparative examples and examples of the present invention are shown;

[0038] Figure 11 : is the Weibull distribution diagram of the interface normal breakdown field strength of the comparative example and embodiment samples of the present invention;

[0039] Among them, 1. Insulation fixing plate; 2. Insulation winding tape; 3. Lifting assembly; 4. Embedded air path; 5. Air inlet; 6. Air outlet; 7. Empty slot; 8. High-voltage electrode; 9. Ground electrode; 10. Nanosecond pulse excitation power supply; 11. Upper dielectric module; 12. Lower dielectric module; 13. Gas cylinder; 14. Flow meter; 15. Bunching roller; 16. Unwinding roller; 17. Second constraint roller; 18. Limiting groove; 19. First constraint roller; 20. Cable conductor; 21. Conductor shielding layer; 22. Body insulation; 23. Soft mold; 24. Temperature-uniform aluminum film; 25. High-temperature resistant polyimide tape; 26. Heat-generating belt; 27. Motor; 28. Slide rail; 29. ​​Flat specimen. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] The purpose of the present invention is to provide a device and method for improving the insulation interface performance of a wrapped submarine cable molded joint to solve the problems existing in the prior art. It can effectively inhibit the accumulation of charge on the insulation interface of the submarine cable molded joint, improve the insulation performance, and increase the breakdown field strength. At the same time, it overcomes the limitations of the prior art and applies plasma discharge technology to the insulation of full-size wrapped submarine cable molded joints to improve their insulation performance and achieve efficient, uniform and reliable insulation recovery.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] The present invention establishes a dielectric barrier discharge plasma reaction system through a device for improving the insulation interface performance of wrapped submarine cable molded joints, and determines the key parameters for the operation of the dielectric barrier discharge plasma system and the movement speed of the transmission device. This technology can significantly suppress the problem of charge accumulation at the interface between insulation layers and improve the breakdown field strength. Specifically, this technology optimizes the micromorphology of the insulation tape surface by applying active particles generated by atmospheric pressure discharge plasma to the surface of the insulation tape, significantly improving the welding quality between the insulation layers. This suppresses the problem of large-scale space charge accumulation under DC stress caused by structural defects at the interlayer interface and improves the breakdown field strength.

[0044] like Figures 1 to 11 As shown, the present invention provides a device for improving the insulation interface performance of a wrapped submarine cable molded joint, which is mainly suitable for wrapped submarine cable molded joints and can also be used for ground wrapped cable joints. The device for improving the insulation interface performance of a wrapped submarine cable molded joint includes a plasma generator, a gas transmission module and a transmission module, wherein the plasma generator includes an upper dielectric module 11 and a lower dielectric module 12, the upper dielectric module 11 is provided with a high-voltage electrode 8, the high-voltage electrode 8 is connected to a nanosecond pulse excitation power supply 10, and the lower dielectric module 12 is provided with a grounding electrode 9, the grounding electrode 9 is connected to the earth, and a plasma discharge channel is formed between the high-voltage electrode 8 and the grounding electrode 9. In the plasma discharge channel, discharge is performed under the action of the high-voltage electrode 8 and the grounding electrode 9 to generate high voltage, and plasma is generated by high-voltage discharge. Both the high-voltage electrode 8 and the grounding electrode 9 can be made of copper foil material, which has good conductivity. It should be noted that: in order to form a dielectric barrier discharge, a barrier medium is provided between the high-voltage electrode 8 and the plasma discharge channel and between the low-voltage electrode 9 and the plasma discharge channel, respectively. The barrier medium can be the upper dielectric module 11 itself and the lower dielectric module 12 itself. The gas delivery module is used to fill the plasma discharge channel with an inert gas so that the surface of the insulating tape 2 can be in an inert gas atmosphere when the surface is treated. The conveying module includes a discharge assembly and a receiving assembly. The discharge assembly is used to store the insulating tape 2 to be treated (using materials such as polypropylene, polyethylene, cross-linked polyethylene, etc.), and the receiving assembly is used to receive the treated insulating tape 2. Thus, the insulating tape 2 passes through the plasma discharge channel from the discharge assembly and is connected to the receiving assembly, forming a continuous treatment process. The treatment effect can be adjusted by controlling the retraction and extension speed of the discharge assembly and the receiving assembly.

[0045] The present invention utilizes a plasma generator to process the insulating tape 2 under an inert gas atmosphere, and can cause active particles generated by atmospheric pressure discharge plasma to act on the surface of the insulating tape 2, effectively suppressing charge accumulation at the insulation interface of the submarine cable molded joint, improving insulation performance, and increasing breakdown field strength. At the same time, the transmission module is utilized to realize the discharging and receiving of the insulating tape 2, which can overcome the limitations of the existing technology and apply plasma discharge technology to the insulation of full-size wrapped submarine cable molded joints to improve their insulation performance and achieve efficient, uniform, and reliable insulation recovery, thereby providing strong technical support for promoting the improvement of my country's independent innovation capabilities of high-end power equipment, supporting the large-scale grid connection of offshore wind power, and ensuring the safe and stable operation of electric energy.

[0046] After the insulating tape 2 is processed by the above-mentioned wrapped submarine cable molded joint insulation interface performance improvement device, the insulating tape 2 can be used for submarine cable connection. In specific implementation, the cable conductors 20 at one end of the two adjacent sections of submarine cables are first welded and wrapped with the conductor shielding layer 21, and then several turns of the insulating tape 2 are wrapped around the original insulating surface of the joint to fill the insulation gaps and restore to the original cable diameter. Finally, the multi-layer insulating tape 2 is melted under the condition of simultaneous heating of the heating cover and the cable conductor 20 to form an insulator. This insulator is used as a recovery insulation. Compared with the existing technology, it can significantly improve the insulation performance and achieve efficient, uniform and reliable insulation recovery.

[0047] In one embodiment, the device further includes a support device, which can be a support structure such as a support frame or a support plate. In this embodiment, an insulating fixing plate 1 is used to support the upper dielectric module 11. The insulating fixing plate 1 also includes holes for connecting electrical wires and gas pipes to the nanosecond pulse excitation power supply 10 and gas cylinder 13, respectively. The device further includes a lifting assembly 3, by which the upper dielectric module 11 is mounted on the insulating fixing plate 1. The lifting assembly 3 may include a slide rail 28 disposed on the insulating fixing plate 1. One end of a support rod is slidably connected to the slide rail 28, and the other end of the support rod is connected to the upper dielectric module 11. The lifting assembly 3 can be used to drive the upper dielectric module 11 to move upward and downward. The lifting and downward movement of the upper dielectric module 11 can change the spacing between the upper dielectric module 11 and the lower dielectric module 12, adjusting the discharge spacing and thereby adjusting the treatment effect of the insulating tape 2.

[0048] In one embodiment, the upper dielectric module 11 is provided with an empty slot 7. The number of the empty slots 7 is set according to demand. At least one is provided, and it can be set to two or more, for example, five. The empty slot 7 runs through the upper dielectric module 11 in the horizontal direction. The movable end of the lifting assembly 3 (for example, the support rod described above) is installed at the top of the empty slot 7 to achieve the lifting and lowering movement of the upper dielectric module 11. The number of support rods can correspond to the number of empty slots 7, or support rods can be set only in the empty slot 7 near the end of the upper dielectric module 11. High-voltage electrodes 8 are installed at the bottom of the empty slot 7. The number can correspond to the number of empty slots 7. The upper dielectric module 11 is used as a blocking medium for discharge. The grounding electrode 9 is installed at the bottom of the lower dielectric module 12. The lower dielectric module 12 is used as a blocking medium for discharge.

[0049] In one embodiment, the barrier medium of the upper dielectric module 11 is a 3D-printed resin material with a thickness of 0.1 cm to 10 cm (preferably 0.2 cm), and the barrier medium of the lower dielectric module 12 is a quartz glass material with a thickness of 0.1 cm to 1.0 cm (preferably 0.2 cm). Both serve as discharge barriers. The upper and lower dielectric modules 11 and 12 are separated by a distance of 0.5 cm to 2 cm (preferably 1 cm). The high-voltage electrode 8 and the ground electrode 9 are both adhesive electrodes with a thickness of 1 mm to 3 mm (preferably 2 mm).

[0050] In one embodiment, the upper dielectric module 11 is provided with an embedded gas path 4, which extends along the upper dielectric module 11 between the slots 7, forming a downward gas flow path. An air inlet 5 is provided at the top of the upper dielectric module 11, and an air outlet 6 is provided at the bottom of the upper dielectric module 11. A single air inlet 5 may be provided, while multiple air outlets 6 may be uniformly provided depending on the length of the plasma discharge channel. Air outlets 6 face the plasma discharge channel, and inert gas is released through the air outlets 6 to form an inert gas atmosphere.

[0051] In one embodiment, the gas delivery module includes a gas cylinder 13 and a flowmeter 14. The gas cylinder 13 stores an inert gas, which can be argon, helium, or nitrogen, among others. The gas cylinder 13 is connected to the gas inlet 5 via a gas pipe. The gas inlet 5 can be connected to the gas outlet 6 via the aforementioned built-in gas path 4. Alternatively, other gas flow paths (e.g., a pipeline independent of the upper medium module 11) can be provided. A flowmeter 14 is provided on the gas pipe to monitor and control the flow rate. The flowmeter 14 can be used to control the flow rate of the inert gas.

[0052] In one embodiment, the discharging assembly includes a discharging roller 16 and a first restraining roller 19, and the receiving assembly includes a bundling roller 15 and a second restraining roller 17. The unprocessed insulating tape 2 is located on the discharging roller 16, and the processed insulating tape 2 is located on the bundling roller 15. The insulating tape 2 passes from the discharging roller 16 through the first restraining roller 19, the plasma discharge channel, and the second restraining roller 17 in sequence to reach the bundling roller 15. The discharging roller 16 is used to unroll the unprocessed insulating tape 2, and the bundling roller 15 is used to bundle the processed insulating tape 2 into a roll. The cooperation of the two can better cater to the processing of insulating tape 2 with a large area and a long length, achieving a level that is truly feasible in engineering. The first restraining roller 19 and the second restraining roller 17 cooperate to restrain the insulating tape 2, straighten the moving insulating tape 2, and allow the insulating tape 2 to pass through the plasma discharge channel stably.

[0053] In one embodiment, the unwinding roller 16, the first restraining roller 19, the second restraining roller 17, and the gathering roller 15 are each connected to an independent drive motor 27. By controlling different drive motors 27, the rotational speed of each roller can be adjusted. The gathering roller 15 and the unwinding roller 16 are located slightly below each end of the lower media module 12, while the first restraining roller 19 and the second restraining roller 17 are located above the gathering roller 15 and the unwinding roller 16, forming a U-shaped structure. The drive motor 27 is mounted on the insulating fixing plate 1, which supports each roller and determines the relative position of each roller.

[0054] In one embodiment, the diameters of the bundling roller 15, the unwinding roller 16, the first constraining roller 19 and the second constraining roller 17 are all the same, which are 3 cm to 7 cm, preferably 5 cm. Each roller is provided with a limiting groove 18 for installing the insulating tape 2 and constraining the movement trajectory of the insulating tape 2.

[0055] Reference again Figures 1 to 11 The present invention also provides a method for improving the insulation interface performance of a wrapped-type submarine cable molded joint, which uses the device for improving the insulation interface performance of a wrapped-type submarine cable molded joint as described above, comprising:

[0056] S1. Place the unprocessed insulating tape 2 on the discharging assembly, and pull out a certain length of the insulating tape 2 through the plasma discharge channel to the receiving assembly to complete the constraint of the moving path of the insulating tape 2.

[0057] S2. Adjust the distance between the upper dielectric module 11 and the lower dielectric module 12 by adjusting the lifting component 3 to meet the set requirements (for example, 0.5 cm to 2 cm), turn on the nanosecond pulse excitation power supply 10 connected to the high-voltage electrode 8, and turn on the gas delivery module to generate plasma in the plasma discharge channel; when the voltage amplitude of the nanosecond pulse excitation power supply 10 is 7 kV to 15 kV, the frequency is 1 kHz to 7 kHz, the pulse width is 500 ns to 2000 ns, the rising and falling edges are 50 ns to 150 ns, and the argon flow rate is 500 mL / min to 5000 mL / min, a plasma with moderate intensity, relatively uniformity, good body plume length and morphology can be generated.

[0058] In one embodiment, the dielectric barrier discharge plasma reaction system parameters and gas flow rate are determined, such as Figure 6 As shown. Preferably, the voltage amplitude of the nanosecond pulse excitation power supply 10 is 10 kV, the frequency is 7 kHz, the pulse width is 800 ns, the rising and falling edges are 100 ns, and the argon flow rate is 1500 mL / min. Preferably, the spacing between the upper dielectric module 11 and the lower dielectric module 12 is 1 cm.

[0059] S3. Start the conveying component, use the discharging component to release the insulating tape 2, and use the receiving component to reel in the insulating tape 2.

[0060] In one embodiment, the bunching roller 15 and the discharge roller 16 are configured to rotate clockwise, while the first constraining roller 19 and the second constraining roller 17 are configured to rotate counterclockwise, with the same and constant speed. The speed of the conveyor is determined. Preferably, the bunching roller 15 and the discharge roller 16 rotate clockwise at a speed of 3 to 6 r / min, preferably 4 r / min, while the first constraining roller 19 and the second constraining roller 17 rotate counterclockwise at a speed of 3 to 6 r / min, preferably 4 r / min.

[0061] S4. After the treatment is completed, turn off the nanosecond pulse excitation power supply 10, the gas delivery module and the transmission module, and remove the treated insulating tape 2.

[0062] In one embodiment, the first constraining roller 19 in the discharging assembly and the second constraining roller 17 in the receiving assembly are used to constrain the insulating tape 2 so that the insulating tape 2 moves along a set trajectory.

[0063] In one embodiment, the following steps are further included:

[0064] S5. Weld the cable conductor 20, wrap the conductor shielding layer 21, and wipe the surface of the body insulation 22 with clean alcohol test paper or other materials.

[0065] S6. Remove the untreated insulating tape 2 at the front and rear ends, and wrap the treated insulating tape 2 around the surface of the conductor shielding layer 21 in circles until the defective insulating area is filled, so that the joint is restored to approximately the same diameter as the cable.

[0066] S7, melting the insulation tape 2 wound one by one into one, completing insulation restoration.

[0067] In one embodiment, if Figure 4 As shown, in step S7, the soft mold 23, the temperature-uniform aluminum film 24 and the high-temperature resistant polyimide tape 25 for shaping and maintaining pressure are installed in sequence (wound circumferentially for at least one circle), and the heat-generating belt 26 is wrapped around the outer diameter side of the high-temperature resistant polyimide tape 25, and is melted into one by synchronous heating with the cable conductor 20.

[0068] The present invention provides experimental verification:

[0069] For the wrapped submarine cable molded joint completed by the above-mentioned method for improving the insulation interface performance of the wrapped submarine cable molded joint, a special cutter is used to cut and restore the insulation layer sample (such as Figure 5 As shown), a block-shaped double-layer interlayer flat plate sample 29 is obtained.

[0070] The treatment effect was verified by setting up a comparative example, which is a double-layer interlayer flat plate sample 29 that has not been treated by the device and method of the present invention, that is, a submarine cable molded joint insulation simulation sample prepared using untreated insulating tape 2.

[0071] The welding quality of the insulation interface of submarine cable molded joints can be characterized by observing the interface micromorphology using a scanning electron microscope (SEM). Figure 8 The following are microscopic images of the interface morphology of the comparative example and the embodiment. In the comparative example, the size and scope of the interface microcracks and air gap defects are larger; in the embodiment, the size and scope of the interface microcracks and air gap defects are reduced, and the interface restoration quality is significantly improved.

[0072] The space charge distribution at the interface between the restored insulation layers of the submarine cable molded joint is characterized by the electroacoustic pulse space charge (PEA) measurement technique. The charge density near the interface reflects the charge accumulation at the sample interface. Figure 9 Figure 3 shows the charge distribution on both sides of the interface between the insulation layers recovered during 1800s of 40kV / mm high-field polarization in the comparative example and the example. In the comparative example, significant opposite-polarity charges accumulate near the interface; in the example, after plasma treatment, this interfacial charge accumulation is significantly alleviated.

[0073] The current integration technique is used to quantify the charge accumulation at the interface between the recovery insulation layers and calculate the conduction current. The collected data is fitted using the following formula to obtain: Figure 10The current integrated charge DCIC-Q(t) curves of the comparative example and example samples are shown.

[0074]

[0075] Where Q(t) is the total integrated charge in coulomb (C); Q(0) is the initial charge in C, which is related to the properties of the sample; Q space is the space charge, unit C, which represents the accumulated space charge in the sample; I cond is the conduction current, the unit is ampere (A), which represents the current component formed by the migration of carriers in the sample; t is the time, the unit is second (s); τ is the time constant.

[0076] It can be seen from the curve that in the comparative example, Q(0)=0.61, Q space =0.019,τ=204.60,I cond =2.61; in the embodiment, all four parameters are reduced, Q(0)=0.60, Q space =0.009,τ=161.60,I cond =1.39, the charge migration rate decreases and the charge accumulation is significantly suppressed.

[0077] The electrical insulation strength of the interface between the insulation layers of the submarine cable molded joint is characterized by measuring the normal breakdown field strength of the sample interface. Figure 11 The Weibull distribution of the normal breakdown field strength at the interface of the comparative example and the example sample is shown in Figure 2. In the comparative example, the normal breakdown field strength at the interface is 348.85 kV / mm; in the example, the breakdown field strength is increased to 367.99 kV / mm, significantly improving the electrical insulation strength.

[0078] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A device for improving the insulation interface performance of a wrapped submarine cable molded joint, characterized in that: include: A plasma generator, comprising an upper dielectric module and a lower dielectric module, wherein the upper dielectric module is provided with a high-voltage electrode, and the lower dielectric module is provided with a ground electrode, wherein a plasma discharge channel is formed between the high-voltage electrode and the ground electrode; a gas delivery module, the gas delivery module being used to fill the plasma discharge channel with an inert gas; and a conveying module, the conveying module comprising a discharging assembly and a receiving assembly, the insulating tape passing through the plasma discharge channel from the discharging assembly and being connected to the receiving assembly; The device further comprises an insulating fixing plate and a lifting assembly, wherein the upper dielectric module is mounted on the insulating fixing plate via the lifting assembly, and the lifting assembly is used to drive the upper dielectric module to move upward and downward; The upper dielectric module is provided with an empty slot, the movable end of the lifting assembly is installed at the top of the empty slot, the high-voltage electrode is installed at the bottom of the empty slot, and the grounding electrode is installed at the bottom of the lower dielectric module; The upper dielectric module is provided with an embedded gas path, which extends along the upper dielectric module between the empty slots. The top of the upper dielectric module is provided with an air inlet, and the bottom of the upper dielectric module is provided with an air outlet, which faces the plasma discharge channel.

2. The device for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 1 is characterized in that: The gas delivery module includes a gas cylinder and a flow meter. The gas cylinder stores the inert gas. The gas cylinder is connected to the gas inlet through a gas pipe. The gas pipe is provided with the flow meter, and the flow meter is used to control the flow of the inert gas.

3. The device for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 1 is characterized in that: The discharging assembly includes a discharging roller and a first restraining roller, and the receiving assembly includes a gathering roller and a second restraining roller. The unprocessed insulating tape is located on the discharging roller, and the processed insulating tape is located on the gathering roller. The insulating tape passes through the first restraining roller, the plasma discharge channel, and the second restraining roller in sequence from the discharging roller to the gathering roller.

4. The device for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 3 is characterized in that: The unwinding roller, the first constraining roller, the second constraining roller and the bundling roller are all connected to independent drive motors, and the drive motors are installed on the insulating fixing plate.

5. A method for improving the insulation interface performance of a wrapped submarine cable molded joint, characterized in that: The device for improving the insulation interface performance of a wrapped submarine cable molded joint according to any one of claims 1 to 4 comprises: S1. Place the unprocessed insulation tape on the discharging assembly, and pull out a certain length of the insulation tape through the plasma discharge channel to the receiving assembly to complete the constraint of the insulation tape movement path; S2. Adjust the distance between the upper dielectric module and the lower dielectric module to meet the set requirements, turn on the high-voltage electrode and the gas delivery module, and generate plasma in the plasma discharge channel; S3, start the conveying component, use the discharging component to release the insulation tape, and use the receiving component to rewind the insulation tape; S4. After the treatment is completed, remove the treated insulation tape.

6. The method for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 5, characterized in that: The first constraint roller in the discharging assembly and the second constraint roller in the receiving assembly are used to constrain the insulating tape, so that the insulating tape can move along a set track.

7. The method for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 5, characterized in that: The following steps are also included: S5. Weld the cable conductor, wrap the conductor shield, and wipe the insulation surface of the body; S6. Remove the untreated insulation tape at the front and rear ends, and wind the treated insulation tape around the surface of the conductor shield layer one circle at a time until the defective insulation area is filled. S7. Melt the insulation tapes wound one by one into one piece to complete the insulation restoration.

Images