Device and method for improving insulation interface performance of wrapping type submarine cable molding joint

Abstract

The invention discloses a wrapping type submarine cable molding joint insulation interface performance improving device and method, and belongs to the technical field of high-voltage direct-current cable insulation, the wrapping type submarine cable molding joint insulation interface performance improving device comprises a plasma generator, a gas conveying module and a conveying module, the plasma generator comprises an upper medium module and a lower medium module, the upper medium module is provided with a high-voltage electrode, and the lower medium module is provided with a high-voltage electrode; the lower dielectric module is provided with a grounding electrode, and a plasma discharge channel is formed between the high-voltage electrode and the grounding electrode; the gas conveying module is used for filling inert gas into the plasma discharge channel; the conveying module comprises a discharging assembly and a collecting assembly, and the insulating winding strip penetrates through the plasma discharging channel from the discharging assembly and is connected to the collecting assembly. According to the invention, charge accumulation of an insulation interface of the submarine cable molded joint can be effectively inhibited, the insulation performance is improved, the breakdown field strength is improved, a plasma discharge technology can be applied to insulation of the full-size wrapping type submarine cable molded joint, the insulation performance is improved, and efficient, uniform and reliable insulation recovery is realized.

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 insulation interface performance of a wrapped submarine cable molded joint. Background Art

[0002] As an important link for grid interconnection and the "artery" for clean energy transmission, the importance of high-voltage direct current submarine cables (hereinafter referred to as "high-voltage direct current submarine cables") is becoming increasingly prominent. With its unique advantages of long distance, large capacity and low loss, high-voltage direct current submarine cables have become key infrastructure for building new power systems and promoting green energy transformation. Among them, long-length high-voltage direct current submarine cables are the key technical support for the grid-connected power generation of clean energy such as offshore wind power.

[0003] In the high-voltage DC submarine cable system, the submarine cable molded joint is the core component for realizing the flexible connection of multiple sections of submarine cables. Its insulation performance directly affects the stability and safety of the entire transmission system. As a common joint production method, the wrapped submarine cable molded joint is achieved by wrapping the insulation tape one circle at a time after the conductor is connected, and the conductor and the heating cover are heated synchronously to achieve melt molding, thereby achieving the purpose of restoring insulation. However, during the melting recovery process, affected by various factors such as interface roughness, surface insulation defects, and crystallization differences, the interface area between the tape layers often produces obvious space charge accumulation, which not only leads to a decrease in 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 joint 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. Existing methods for suppressing interface charge and improving performance mainly include spraying ZnO and sandpaper polishing. Although these methods can improve the quality of insulation recovery 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 possible 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 novel 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, wherein the plasma generator comprises an upper dielectric module and a lower dielectric module, the upper dielectric module is provided with a high-voltage electrode, the lower dielectric module is provided with a grounding electrode, and a plasma discharge channel is formed between the high-voltage electrode and the grounding electrode; the gas delivery module is used for filling the plasma discharge channel with an inert gas; the transmission module comprises a discharging assembly and a receiving assembly, and an insulating tape passes through the plasma discharge channel from the discharging assembly and is connected to the receiving assembly.

[0009] In one embodiment, it further includes 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, the embedded gas path extends along the upper dielectric module between the empty grooves, the top of the upper dielectric module is provided with an air inlet, the bottom of the upper dielectric module is provided with an air outlet, and the air outlet 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 via 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 material discharging assembly includes a discharging roller and a first restraining roller, and the material 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, using the device for improving the insulation interface performance of a wrapped type submarine cable molded joint as described above, comprising:

[0016] S1, placing an unprocessed insulating tape on a discharging assembly, and pulling out a certain length of the insulating tape through a plasma discharge channel to a receiving assembly, thereby constraining the moving path of the insulating tape;

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

[0018] S3, start the conveying component, use the discharging component to release the insulating tape, and use the receiving component to reel in the insulating 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 moves along a set trajectory.

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

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

[0023] S6, removing the untreated insulating tape at the front end and the rear end, and winding the treated insulating tape around the surface of the conductor shielding layer circle by circle until the defective insulating 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 inhibiting charge accumulation on the insulating 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 discharging and receiving of the insulating tape, and the limitations of the prior art can be overcome. The plasma discharge technology is applied to the insulation of the full-size wrapped submarine cable molded joint to improve its insulation performance and realize efficient, uniform, and reliable insulation recovery, thereby providing strong technical support for promoting the improvement of my country's independent innovation capability of high-end power equipment, supporting 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 drawings required for use in the embodiments will be briefly introduced below. 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 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 It is 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 It is a side view of a device for improving the insulation interface performance of a wrapped submarine cable molded joint in 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 It is a 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 in an embodiment of the present invention;

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

[0036] Fig. 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] Fig.10 The DCIC-Q(t) curves of the comparative examples and the samples of the embodiments of the present invention are shown in FIG.

[0038] Fig.11 The Weibull distribution diagram of the normal breakdown field strength of the interface of the comparative example and the example 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-averaging 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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, 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, the limitations of the prior art are overcome, and plasma discharge technology is applied to the insulation of a full-size wrapped submarine cable molded joint to improve its 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 builds a dielectric barrier discharge plasma reaction system through a device for improving the insulation interface performance of a wrapped submarine cable molded joint, and determines the key parameters of the dielectric barrier discharge plasma system and the movement speed of the transmission device. This technology can largely suppress the charge accumulation problem at the interface between the insulation layers and improve the breakdown field strength. Specifically, this technology optimizes the microscopic morphology of the surface of the insulation tape by allowing the active particles generated by the atmospheric pressure discharge plasma to act on the surface of the insulation tape, thereby greatly improving the welding quality between the insulation layers. Thereby suppressing the problem of a large amount of space charge accumulation under DC stress caused by structural defects at the interface between the layers, and improving 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 applied to 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, 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 may 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, and the treatment effect can be adjusted by controlling the retracting and releasing speeds 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 inhibiting 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 2, and the limitations of the prior art can be overcome. The plasma discharge technology is applied to the insulation of the full-size wrapped submarine cable molded joint to improve its insulation performance and realize efficient, uniform, and reliable insulation recovery, thereby providing strong technical support for promoting the improvement of my country's independent innovation capability of high-end power equipment, supporting 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 conductor 20 at one end of the two adjacent sections of the submarine cable is first welded and wrapped with the conductor shielding layer 21, and then several turns of the insulating tape 2 are wrapped on 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 hood and the cable conductor 20 to form an insulator. The insulator is used as a recovery insulation. Compared with the prior art, it can significantly improve the insulation performance and achieve efficient, uniform and reliable insulation recovery.

[0047] In one embodiment, it also includes a supporting device, which can be a supporting structure such as a supporting frame and a supporting plate. In the embodiment, an insulating fixing plate 1 is used to support the upper dielectric module 11. At the same time, the insulating fixing plate 1 is also provided with holes for connecting the wires and the gas pipe to the nanosecond pulse excitation power supply 10 and the gas cylinder 13 respectively. It also includes a lifting component 3, and the upper dielectric module 11 is installed on the insulating fixing plate 1 through the lifting component 3. The lifting component 3 may include a slide rail 28 provided on the insulating fixing plate 1, one end of the 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 upper dielectric module 11 can be driven to move up and down through the lifting component 3. The lifting and moving of the upper dielectric module 11 can change the distance between the upper dielectric module 11 and the lower dielectric module 12, adjust the discharge distance, and thus adjust the treatment effect of the insulating tape 2.

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

[0049] In one embodiment, the blocking 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 blocking 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 of which can be used as a blocking medium for discharge. The upper dielectric module 11 and the lower dielectric module 12 are separated by 0.5 cm to 2 cm (preferably 1 cm). Both the high-voltage electrode 8 and the grounding electrode 9 are 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 to form a gas flow path from top to bottom. The top of the upper dielectric module 11 is provided with an air inlet 5, and the bottom of the upper dielectric module 11 is provided with an air outlet 6. Only one air inlet 5 may be provided, and a plurality of air outlets 6 may be uniformly provided according to the length of the plasma discharge channel. Moreover, the air outlet 6 faces the plasma discharge channel, and the inert gas is released through the air outlet 6 to form an inert gas atmosphere.

[0051] In one embodiment, the gas delivery module includes a gas cylinder 13 and a flow meter 14. The gas cylinder 13 stores an inert gas, and the inert gas can be argon, helium or nitrogen. The gas cylinder 13 is connected to the gas inlet 5 through a gas pipe. The gas inlet 5 can be connected to the gas outlet 6 through the embedded gas path 4 described above. Of course, other circulation paths (such as pipelines independent of the upper medium module 11) can also be provided. The gas pipe is provided with a flow meter 14, which has the function of monitoring and controlling the flow rate. The flow rate of the inert gas can be controlled by the flow meter 14.

[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 through the first restraining roller 19, the plasma discharge channel, and the second restraining roller 17 from the discharging roller 16 to the bundling roller 15. The discharging roller 16 is used to unfold the unprocessed insulating tape 2, and the bundling roller 15 is used to bundling the processed insulating tape 2 into a roll. The cooperation of the two can better cater to the processing of insulating tapes 2 with large areas and lengths, and reach a level that is truly achievable 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 stably pass through the plasma discharge channel.

[0053] In one embodiment, the unwinding roller 16, the first constraint roller 19, the second constraint roller 17 and the bunching roller 15 are all connected to independent drive motors 27, and the rotation speed of any roller can be adjusted by controlling different drive motors 27. The bunching roller 15 and the unwinding roller 16 are located at the lower part of both ends of the lower medium module 12, and the first constraint roller 19 and the second constraint roller 17 are located above the bunching roller 15 and the unwinding roller 16, forming a U-shaped shape as a whole. The drive motor 27 is installed on the insulating fixing plate 1, and the insulating fixing plate 1 is used to support each roller and determine the relative position between different rollers.

[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, using 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, thereby constraining the moving path of the insulating tape 2.

[0057] S2. Adjust the spacing between the upper medium module 11 and the lower medium module 12 to meet the set requirements (for example, 0.5 cm to 2 cm) by adjusting the lifting component 3, 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 gas flow rate is 500 mL / min to 5000 mL / min, a plasma with moderate intensity, relatively uniformity, and good body feather 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 edge and the falling edge are 100 ns, and the argon gas 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 unwinding roller 16 are set to rotate clockwise, and the first constraint roller 19 and the second constraint roller 17 are set to rotate counterclockwise, with the same and constant speed. The speed of the conveying device is determined, preferably the bunching roller 15 and the unwinding roller 16 rotate clockwise, with a speed of 3r / min to 6r / min, preferably 4r / min, and the first constraint roller 19 and the second constraint roller 17 rotate counterclockwise, with a speed of 3r / min to 6r / min, preferably 4r / 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 also 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 insulating tape 2 wound circle by circle into one piece, and completing the insulation restoration.

[0067] In one embodiment, if Figure 4 As shown, in step S7, a soft mold 23, a temperature-averaging aluminum film 24 and a high-temperature resistant polyimide tape 25 for shaping and maintaining pressure are installed in sequence (wound circumferentially for at least one circle), and a heat-generating belt 26 is wound 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), to obtain a block-shaped double-layer interlayer flat plate sample 29.

[0070] The treatment effect is verified by setting 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 by using an untreated insulating tape 2.

[0071] The welding quality of the insulation interface of the submarine cable molded joint can be characterized by observing the interface microstructure using a scanning electron microscope (SEM). Figure 8 The microscopic morphology images of the interface of the comparative example and the embodiment are shown in FIG. In the comparative example, the size and range of the interface microcrack air gap defects are relatively large; in the embodiment, the size and range of the interface microcrack air gap defects are reduced, and the interface restoration quality is significantly improved.

[0072] The electroacoustic pulse space charge (PEA) measurement technique is used to characterize the spatial charge distribution at the interface between the restored insulation layers of the submarine cable molded joint. The charge density near the interface between the layers reflects the accumulation of charge on the sample interface. Fig. 9 The charge distribution on both sides of the interface between the insulating layers is restored in the comparative example and the example after 1800s of 40kV / mm high field polarization. In the comparative example, obvious opposite polarity charges are accumulated near the interface; in the example, after plasma treatment, the interface charge accumulation phenomenon is significantly alleviated.

[0073] The current integration technique is used to quantify the charge accumulation at the interface between the restored insulating layers and calculate the conductance current. The following formula is used to fit the collected data and obtain: Fig.10The current integrated charge DCIC-Q(t) curves of the comparative example and example samples are shown.

[0074]

[0075] Where Q(t) is the integrated total 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 inhibited.

[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. Fig.11 The Weibull distribution of the normal breakdown field strength of the interface of the comparative example and the example sample. In the comparative example, the normal breakdown field strength of the interface is 348.85 kV / mm; in the example, the breakdown field strength is increased to 367.99 kV / mm, and the electrical insulation strength is significantly improved.

[0078] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood 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, the plasma generator comprising 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 ground electrode, a plasma discharge channel being formed between the high voltage electrode and the ground electrode; A gas delivery module, the gas delivery module is used to fill the plasma discharge channel with an inert gas; And a conveying module, the conveying module includes a discharging component and a receiving component, the insulating tape passes through the plasma discharge channel from the discharging component and is connected to the receiving component.

2. The device for improving insulation interface performance of wrapped submarine cable molded joint according to claim 1 is characterized in that: It also includes an insulating fixing plate and a lifting assembly, the upper dielectric module is installed on the insulating fixing plate through the lifting assembly, and the lifting assembly is used to drive the upper dielectric module to move up and down.

3. The device for improving insulation interface performance of wrapped submarine cable molded joint according to claim 2 is characterized in that: 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.

4. The device for improving insulation interface performance of a wrapped submarine cable molded joint according to claim 3 is characterized in that: 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.

5. The device for improving insulation interface performance of wrapped submarine cable molded joint according to claim 4 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.

6. The device for improving insulation interface performance of wrapped submarine cable molded joint according to claim 2 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.

7. The device for improving insulation interface performance of wrapped submarine cable molded joint according to claim 6 is characterized in that: The unwinding roller, the first constraining roller, the second constraining roller and the bundling roller are all connected to independent driving motors, and the driving motors are mounted on the insulating fixing plate.

8. 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 7 comprises: S1, placing an unprocessed insulating tape on a discharging assembly, and pulling out a certain length of the insulating tape through a plasma discharge channel to a receiving assembly, thereby constraining the moving path of the insulating tape; S2, adjusting the distance between the upper dielectric module and the lower dielectric module to meet the set requirements, turning on the high-voltage electrode and the gas delivery module, and generating plasma in the plasma discharge channel; S3, start the conveying component, use the discharging component to release the insulating tape, and use the receiving component to reel in the insulating tape; S4. After the treatment is completed, remove the treated insulation tape.

9. The method for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 8, 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 is kept moving along a set track.

10. The method for improving the insulation interface performance of a wrapped submarine cable molded joint according to claim 8, characterized in that: The following steps are also included: S5. Weld the cable conductor, wrap the conductor shielding layer, and wipe the insulation surface of the body; S6, removing the untreated insulating tape at the front end and the rear end, and winding the treated insulating tape around the surface of the conductor shielding layer circle by circle until the defective insulating area is filled; S7. Melt the insulation tapes wound one by one into one piece to complete the insulation restoration.

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