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

Abstract

The invention discloses a cable molding joint interface insulation performance improving device and method, and relates to the technical field of cable molding joint insulation, and the cable molding joint interface insulation performance improving device comprises a plasma jet reaction system and a mechanical motion control system; the plasma jet reaction system comprises a plasma generator and a gas conveying system, and the plasma generator is configured to activate a gas medium in a plasma generation cavity to form plasma and spray the plasma to a to-be-processed surface of the cable; the gas conveying system is used for conveying a gas medium to the plasma generation cavity; the mechanical motion control system is configured to drive circumferential rotation of the plasma generator about the cable. The technology can effectively improve the interface insulation performance of the cable molding joint.

Description

Technical Field

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

[0002] As the core equipment of offshore wind power, high-voltage submarine cables are an important prerequisite for offshore energy development. Cable molded joints are essential components to ensure long-length submarine power transmission. The manufacturing process of cable molded joints is to inject molten material through the injection port and weld it with the cable body after the conductors are connected. However, this process will introduce more insulation defects, resulting in a decrease in electrical performance. Especially under the action of a DC electric field, insulation defects will cause electric field distortion, thereby generating normal and tangential electric fields, which further reduces insulation performance. The existing methods for improving related interface performance remain at the optimization of the manufacturing process parameters of cable molded joints, and have reached a bottleneck in further improving insulation performance. Based on this, a new solution is urgently needed to solve the above problems. Summary of the invention

[0003] The purpose of the present invention is to provide a device and method for improving the insulation performance of the interface of a cable molded joint, so as to solve the problems existing in the above-mentioned prior art and effectively improve the insulation performance of the interface of the cable molded joint.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a device for improving the insulation performance of a cable molded joint interface, comprising: a plasma jet reaction system and a mechanical motion control system; the plasma jet reaction system comprises a plasma generator and a gas delivery system, the plasma generator is configured to activate a gas medium in a plasma generation chamber to form plasma and spray the plasma onto a cable surface to be processed; the gas delivery system is used to deliver the gas medium to the plasma generation chamber; the mechanical motion control system is configured to drive the plasma generator to rotate around the circumference of the cable.

[0006] Preferably, the mechanical motion control system includes a cable ring clamp, a support member and a rotation drive device, the cable ring clamp includes two semicircular ring members, the two semicircular ring members are detachably connected, the two semicircular ring members can be buckled on the cable, the cable ring clamp is configured with an annular track, when the cable ring clamp is installed on the cable, the annular track is coaxial with the part of the cable to be processed, the support member is slidably arranged on the annular track, the rotation drive device is used to drive the support member to rotate on the annular track, the plasma generator is fixedly connected to the support member, and the plasma jet port of the plasma generator faces the surface of the cable to be processed.

[0007] Preferably, the rotation drive device includes a stepper motor, a sun gear and a driving gear; the sun gear is sleeved and fixed on the outside of the cable ring clamp, the stepper motor is fixedly connected to the support member, the driving gear is fixedly connected to the motor shaft of the stepper motor, and the driving gear and the sun gear are meshed for transmission.

[0008] Preferably, the two semicircular ring members are connected by a spring self-locking device; the spring self-locking device includes a lock core, a spring block, a spring and a pull rod, the surfaces of the two semicircular ring members that are interlocked and in contact with each other are respectively a first end face and a second end face, two of the first end face and two of the second end face are each provided, the lock core is fixedly provided on the first end face, the bottom structure of the lock core is expanded, two of the spring blocks, the pull rod and the spring are each provided, a slide is provided in the semicircular ring member on one side of the second end face, the slide is provided parallel to the axis of the cable ring clamp, the two spring blocks are provided in the slide and close to the middle, and the two spring blocks are provided on the slide opposite to each other. A spring is provided inside each of the two spring blocks, and the spring gives an elastic force to the two spring blocks to move closer to each other. Under normal circumstances, the distance between the two spring blocks is smaller than the size of the bottom structure of the lock core. An inclined guide surface is provided on the opposite side of the spring block, and the distance between the two guide surfaces increases from the bottom to the top. One end of the pull rod is fixedly connected to the spring block, and the other end extends along the slide and extends out from the side of the semicircular ring member; when the two semicircular ring members are buckled on the outside of the cable and approach each other, the lock core can enter between the two spring blocks and achieve locking, and the lock core can be unlocked by pulling the spring blocks in opposite directions by the pull rod.

[0009] Preferably, it also includes a horizontal telescopic rod and an inclined telescopic rod, one end of the horizontal telescopic rod is fixedly connected to the side of the support member facing the part to be processed, and the other end is fixedly connected to one end of the inclined telescopic rod, and the other end of the inclined telescopic rod is fixedly connected to the plasma generator.

[0010] Preferably, the plasma generator comprises a high-voltage needle electrode, a grounded ring electrode, a nanosecond pulse power supply and a quartz glass tube; the plasma generating chamber is formed in the quartz glass tube, the high-voltage needle electrode is connected to the nanosecond pulse power supply and one end thereof extends from the top of the quartz glass tube into the quartz glass tube, the grounded ring electrode is sleeved on the outer circumference of the quartz glass tube below the high-voltage needle electrode, the grounded ring electrode is grounded, the nanosecond pulse power supply applies a voltage to the high-voltage needle electrode, the outer wall of the quartz glass tube serves as a barrier medium for discharge, and a jet-like plasma jet is generated.

[0011] Preferably, the gas delivery system comprises a high-purity argon gas cylinder and a flow meter, the high-purity argon gas cylinder is connected to the quartz glass tube through a gas pipe, and the flow meter is provided on the gas pipe.

[0012] Preferably, the diameter of the quartz glass tube is 4 cm and the length is 20 cm, the diameter of the high-voltage needle electrode is 1 cm and the length is 30 cm, and the lower end is 6 cm away from the lower end of the quartz glass tube; the grounding ring electrode is tightly attached to the outer wall of the quartz glass tube and fixed at 3 cm away from the lower end of the high-voltage needle electrode.

[0013] The present invention also provides a method for improving the insulation performance of the interface of a cable molded joint, comprising: using the above-mentioned device for improving the insulation performance of the interface of a cable molded joint to treat the cable; the steps are as follows:

[0014] S1: According to the manufacturing process of submarine cable molded joints, after welding the cable conductor and wrapping the conductor shielding layer, wipe the insulation surface of the cable body with clean alcohol test paper;

[0015] S2: Install the mechanical motion control system on the cable;

[0016] S3: start the plasma jet reaction system;

[0017] S4: The mechanical motion control system drives the plasma generator to rotate unidirectionally or reciprocatingly;

[0018] S5: After the treatment is completed, the mechanical motion control system and the plasma jet reaction system are turned off; the position of the plasma generator is adjusted to move the set distance along the inclined surface of the cable body insulation, and steps S3 and S4 are repeated until the entire area of ​​the cable body insulation is treated;

[0019] S6: Remove the mechanical motion control system and, according to the cable molded connector insulation preparation process, cast the recovery insulation on the cable body insulation to restore the insulation.

[0020] Preferably, before actual use, multiple tests are performed to determine the time for interface treatment and the optimal operating parameters of the plasma jet reaction system and the mechanical motion control system.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The present invention first designs and builds a plasma jet reaction system and a device that can be used for the interface treatment of DC cable molded joints, then provides a method for using the device, and finally preferably determines the parameters such as the time of interface treatment. This technology can fill the gap in plasma treatment of the insulation interface of cable molded joints. The plasma jet used can better cater to irregular three-dimensional special-shaped insulation structures and reach a level that is truly achievable in engineering. In the future, the supporting equipment will be further upgraded to achieve the modification of the insulation interface of large-scale cable molded joints and optimize the factory preparation process of molded joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] Figure 1 A flow chart of a method for improving the insulation performance of a cable molded joint interface provided by an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of a device for improving the insulation performance of a cable molded joint interface and a method for using the device in accordance with an embodiment of the present invention;

[0026] Figure 3 It is a structural diagram of a cable ring clamp and a rotary drive device in an embodiment of the present invention;

[0027] Figure 4 It is a cross-sectional structural diagram of a cable ring clamp and a rotary drive device in an embodiment of the present invention;

[0028] Figure 5 This is a structural diagram of the interior of the cable ring clamp and the spring self-locking device in an embodiment of the present invention;

[0029] Figure 6 for Figure 2 Discharge images of plasma jets in plasma jet reaction systems under different operating parameters;

[0030] Figure 7 This is a schematic diagram of cutting a block-shaped double-layer flat plate sample in an embodiment of the present invention;

[0031] Figure 8 The interface SEM morphology of the comparative example and the example sample in the present invention;

[0032] Fig. 9 The interfacial space charge distribution characteristics of the comparative examples and example samples of the present invention;

[0033] Fig.10The Weibull distribution diagram of the normal breakdown field strength of the interface of the comparative example and the example sample of the present invention;

[0034] In the figure: 1-high-voltage needle electrode; 2-ground ring electrode; 3-quartz glass tube; 4-three-way connector; 5-high-purity argon bottle; 6-flow meter; 7-nanosecond pulse power supply; 8-hot melt adhesive; 9-cable body insulation; 10-restoration insulation; 11-cable ring clamp; 12-horizontal telescopic rod; 13-tilted telescopic rod; 14-rotation drive device; 15-circular ring body; 16-circular track; 17-circular outer plate; 18-spring self-locking device; 19-sun gear; 20-lock cylinder; 21-spring block; 22-spring; 23-roller; 24-pull rod; 25-stepping motor; 26-speed controller; 27-motor shaft; 28-driving gear; 29-track wheel; 30-fixed plate; 31-protective plate; 32-cable conductor; 33-conductor shielding layer. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] In the art, when connecting cables such as submarine cables, it is necessary to first weld the conductors at one end of two adjacent sections of submarine cables and wrap the conductor shielding layer, and then inject an insulator at the joint. This insulator is called recovery insulation in this specification, and the insulator that comes with the submarine cable when it leaves the factory is the cable body insulation. Usually, the cable body insulation at the joint is a cone surface, such as Figure 2 As shown, the conical surface is a three-dimensional special-shaped structure, which is difficult to perform insulation improvement treatment. Based on this, the following embodiments of the present invention solve this problem.

[0038] Combine the following Figures 1 to 10 , describing an embodiment of the present invention.

[0039] The present invention provides a device for improving the insulation performance of the interface of a cable molded joint, which is suitable for treating submarine cables and large-diameter cables used on the ground, such as Figure 2 to Figure 5As shown, it includes: a plasma jet reaction system and a mechanical motion control system; the plasma jet reaction system includes a plasma generator and a gas delivery system, the plasma generator is configured to activate a gas medium in a plasma generating chamber to form plasma and spray it onto a surface to be treated of the cable, the surface to be treated is usually a conical surface, and the gas delivery system is used to deliver the gas medium to the plasma generating chamber; the mechanical motion control system is configured to drive the plasma generator to rotate around the circumference of the cable.

[0040] The embodiment of the present invention realizes plasma treatment of the surface to be treated at the cable molded joint. The plasma jet used can better cater to the irregular three-dimensional special-shaped insulation structure, reaching a level that is truly achievable in engineering. In the future, the supporting equipment will be further upgraded to realize the modification of the insulation interface of large-scale cable molded joints and optimize the factory preparation process of molded joints.

[0041] Specifically, the mechanical motion control system includes a cable ring clamp 11, a support and a rotation drive device 14. The cable ring clamp 11 includes two semicircular rings, which are detachably connected and can be buckled on the cable. The cable ring clamp 11 is configured with an annular track 16. When the cable ring clamp 11 is installed on the cable, the annular track 16 is coaxial with the portion of the cable to be processed, the support is slidably arranged on the annular track 16, and the rotation drive device 14 is used to drive the support to rotate on the annular track 16. The plasma generator is fixedly connected to the support, and the plasma jet of the plasma generator faces the surface of the cable to be processed.

[0042] This embodiment realizes the installation of a mechanical motion control system on an infinitely long cable. During installation, the cable ring clamp 11 is sleeved on one side of the joint, and the plasma generator is directly opposite the surface to be processed at the joint, which is a conical surface or other types of three-dimensional special-shaped insulating structures.

[0043] In some embodiments, the rotation drive device 14 includes a stepper motor 25, a sun gear 19 and a driving gear 28; the sun gear 19 is sleeved and fixed on the outer side of the cable ring clamp 11, the stepper motor 25 is fixedly connected to the support, the driving gear 28 is fixedly connected to the motor shaft 27 of the stepper motor 25, and the driving gear 28 and the sun gear 19 are meshed for transmission.

[0044] In order to facilitate the control of the operation of the stepper motor 25 , a speed controller 26 is further included. The speed controller 26 is connected to the stepper motor 25 and controls the operation of the stepper motor 25 .

[0045] In this embodiment, the stepping motor 25 drives the driving gear 28 to rotate on the sun gear 19 and drives the supporting member and the plasma generator to rotate around the cable.

[0046] It can be understood that the sun gear 19 is also a split structure, and the two split parts are combined to form the entire ring-shaped sun gear 19.

[0047] Specifically, Figure 3-4 As shown, the rotation drive device 14 includes two fixed plates 30 and a protective plate 31. The two fixed plates 30 are arranged opposite to each other and are respectively located on both sides of the cable ring clamp 11. The protective plate 31 is fixed to the top of the fixed plate 30. The fixed plate 30, the protective plate 31 and the cable ring clamp 11 enclose an accommodating space. The stepper motor 25 and the driving gear 28 are arranged in the accommodating space. Annular grooves are arranged on both sides of the cable ring clamp 11 to form an annular track 16. A track wheel 29 is arranged on the opposite side of the fixed plate 30. The fixed plate 30 is arranged in the annular groove and is in rolling contact with one side or multiple side surfaces of the annular groove.

[0048] For example Figure 3-4 As shown, the cable ring clamp 11 includes a circular ring body 15, a circular outer plate 17, and an inner ring connecting the circular ring body 15 and the circular outer plate 17. The inner ring, the circular ring body 15, and the circular outer plate 17 enclose the above-mentioned circular groove.

[0049] In some embodiments, the two semicircular ring members are connected by a spring self-locking device 18; the spring self-locking device 18 includes a lock core 20, a spring block 21, a spring 22 and a pull rod 24, and the surfaces of the two semicircular ring members that are interlocked and in contact with each other are respectively a first end face and a second end face, and the first end face and the second end face are both provided with two, a lock core 20 is fixedly provided on the first end face, and the bottom structure of the lock core 20 is expanded, and the spring block 21, the pull rod 24 and the spring 22 are each provided with two, and a slide is provided in the semicircular ring member on one side of the second end face, and the slide is arranged parallel to the axis of the cable ring clamp 11, and the two spring blocks 21 are both arranged in the slide and arranged close to the middle, and a spring 22 is provided in the slide on the opposite side of the two spring blocks 21, and the spring 22 gives The two spring blocks 21 have an elastic force that is close to each other. Under normal circumstances, the distance between the two spring blocks 21 is smaller than the size of the bottom structure of the lock core 20. An inclined guide surface is provided on the opposite side of the spring block 21, and the distance between the two guide surfaces increases from the bottom to the top. One end of the pull rod 24 is fixedly connected to the spring block 21, and the other end extends along the slide and extends from the side of the semicircular ring member; when the two semicircular ring members are buckled on the outside of the cable and close to each other, the lock core 20 can enter between the two spring blocks 21 and achieve locking. The lock core 20 can be unlocked by pulling the spring blocks 21 in opposite directions by the pull rod 24. A lock port connecting the channel between the two spring blocks 21 is provided on the first end face, and the lock core 20 enters between the two spring blocks 21 from the lock port.

[0050] In this embodiment, a lock core 20 is disposed at both ends of one of the semicircular ring members, and two spring blocks 21, a spring 22 and a pull rod 24 are disposed at both ends of the other semicircular ring member.

[0051] When the cable molded joint needs to be plasma treated, two semicircular rings are arranged on opposite sides of the cable, and then the two semicircular rings are closed. When closed, the lock core 20 enters the lock port and is pressed against the two guide surfaces, and a component force is applied to the spring block 21 to move outward along the slideway. Under this component force, the two spring blocks 21 move toward both sides and the expanded structure at the bottom of the lock core 20 enters between the two spring blocks 21. When it is necessary to unlock, the pull rod 24 is manually pulled to overcome the elastic force of the spring 22. At this time, the distance between the two spring blocks 21 increases, and then the two semicircular rings are moved in opposite directions to unlock and remove the mechanical motion control system.

[0052] Understandable, such as Figure 5 As shown, the bottoms of the two spring blocks 21 are provided with recessed portions, and the two recessed portions are used to accommodate the lock core 20 .

[0053] In some embodiments, a roller 23 is provided at the bottom of the spring block 21 , and the roller 23 is in rolling contact with the bottom surface of the slideway, so that the friction between the spring block 21 and the slideway can be reduced, thereby making it easier to insert the lock core 20 between the two spring blocks 21 .

[0054] In some embodiments, the embodiments of the present invention also include a horizontal telescopic rod 12 and an inclined telescopic rod 13, one end of the horizontal telescopic rod 12 is fixedly connected to a side of the support member facing the part to be treated, and the other end is fixedly connected to one end of the inclined telescopic rod 13, and the other end of the inclined telescopic rod 13 is fixedly connected to the plasma generator.

[0055] In this embodiment, the horizontal telescopic rod 12 and the inclined telescopic rod 13 are both electric telescopic rods.

[0056] In some embodiments, the plasma generator includes a high-voltage needle electrode 1, a grounded ring electrode 2, a nanosecond pulse power supply 7 and a quartz glass tube 3; a plasma generating chamber is formed in the quartz glass tube 3, the high-voltage needle electrode 1 is connected to the nanosecond pulse power supply 7 and one end thereof extends from the top of the quartz glass tube 3 into the quartz glass tube 3, a grounded ring electrode 2 is sleeved on the outer periphery of the quartz glass tube 3 below the high-voltage needle electrode 1, the grounded ring electrode 2 is grounded, the nanosecond pulse power supply 7 applies voltage to the high-voltage needle electrode 1, and the outer wall of the quartz glass tube 3 serves as a blocking medium for discharge, thereby generating a jet-like plasma jet. The gas delivery system includes a high-purity argon gas bottle 5 and a flowmeter 6, the high-purity argon gas bottle 5 is connected to the quartz glass tube 3 through a gas pipe, and a flowmeter 6 is provided on the gas pipe.

[0057] Specifically, Figure 2, one end of the three-way joint 4 is connected to the high-purity argon bottle 5, and the other end is used to fix the quartz glass tube 3. One end of the high-voltage needle electrode 1 is connected to the nanosecond pulse power supply 7, and the other end is fixed to the center of the quartz glass tube 3 through the three-way joint 4 with hot melt adhesive 8. The diameter of the quartz glass tube 3 is 4 cm, and the length is 20 cm. The diameter of the high-voltage needle electrode 1 is 1 cm, the length is 30 cm, and the lower end is 6 cm away from the lower end of the quartz glass tube 3; the grounding ring electrode 2 is tightly attached to the outer wall of the quartz glass tube 3 and fixed 3 cm away from the lower end of the high-voltage needle electrode 1.

[0058] It can be understood that the present invention is not limited to the specific structure of the plasma jet reaction system described above. In other embodiments of the present invention, any device capable of generating a plasma jet in the prior art may be used.

[0059] The present invention also provides a method for improving the insulation performance of the interface of a cable molded joint, comprising: using the above-mentioned device for improving the insulation performance of the interface of a cable molded joint to process the cable; the steps are as follows:

[0060] S1: After welding the conductor of the cable molded connector and wrapping the conductor shielding layer, wipe the insulation surface of the cable body 9 with a clean alcohol test paper;

[0061] S2: Install the mechanical motion control system on the cable;

[0062] S3: start the plasma jet reaction system;

[0063] S4: The mechanical motion control system drives the plasma generator to rotate unidirectionally or reciprocatingly;

[0064] S5: After the treatment is completed, the mechanical motion control system and the plasma jet reaction system are turned off; the position of the plasma generator is adjusted to move the set distance along the inclined surface of the cable body insulation 9, and steps S3 and S4 are repeated until the entire area of ​​the cable body insulation 9 is treated;

[0065] S6: Remove the mechanical motion control system, and according to the cable molded joint insulation preparation process, cast the recovery insulation 10 on the cable body insulation 9 to restore the insulation.

[0066] In some embodiments, before actual use, multiple tests are performed to determine the time for interface treatment and the optimal operating parameters of the plasma jet reaction system and the mechanical motion control system.

[0067] Specifically, Figure 1 shown.

[0068] S1: According to the manufacturing process of the submarine cable molded joint, after the cable conductor 32 is welded and the conductor shielding layer 33 is wrapped, the surface of the cable body insulation 9 is wiped with a clean alcohol test paper;

[0069] S2: Put the cable ring clamp 11 on the cable and fix it through the spring self-locking device 18, and adjust its position so that the bottom of the plasma jet reaction system is at the top of the inclined surface of the cable body insulation 9. Adjust the position of the plasma jet reaction system so that the distance between the bottom and the cable body insulation 9 is 1 to 10 cm;

[0070] Through experiments, it is preferred that the distance between the bottom of the plasma jet reaction system and the cable body insulation 9 is 5 cm.

[0071] S3: Open the argon gas bottle and control the gas flow rate. After the gas flow rate is stable, apply nanosecond pulse high voltage to the high-voltage needle electrode 1, and the outer wall of the quartz glass tube 3 acts as a barrier medium for discharge, generating a jet-like plasma jet that flows to the surface of the cable body insulation 9 of the cable molded joint to modify it.

[0072] By adjusting the voltage amplitude and frequency parameters of the nanosecond pulse excitation source, the discharge intensity and uniformity can be controlled; by adjusting the argon gas flow rate, the plasma plume length and morphology can be controlled; Figure 6 As shown, the voltage amplitude of the nanosecond pulse excitation source is preferably 12 kV, the frequency is 5 kHz, and the argon gas flow rate is 1000 mL / min. At this time, the discharge has the best body plume shape and intensity.

[0073] S4: Turn on the speed controller 26 to set and control the rotation speed and time of the upper driving gear 28;

[0074] To avoid entanglement of lines and gas paths, the rotary drive device 14 is set to drive the plasma generator to rotate 180° forward, then reverse 360°, and finally rotate 180° forward to return to the original position for one treatment. Through experiments, the rotation speed of the plasma generator is preferably 1 r / min, and the number of treatments is twice.

[0075] S5: After the treatment is completed, turn off the nanosecond pulse power supply 7, rotate the controller, adjust the displacement of the inclined telescopic rod 13, so that the lower end of the quartz glass tube 3 moves 1 to 4 cm along the inclined surface of the cable body insulation 9, and repeat steps S3 and S4 until the entire area of ​​the cable body insulation 9 is treated;

[0076] Through experiments, it is preferred that the lower end of the quartz glass tube 3 moves 4 cm along the inclined surface of the cable body insulation 9.

[0077] S6: Finally, the cable ring clamp 11 is removed, and according to the cable molded joint insulation preparation process, the recovery insulation 10 is poured on the cable body insulation 9 to perform insulation recovery.

[0078] like Figure 7After completing the above steps, use a special carving knife to cut the interface area to obtain a block-shaped double-layer flat sample. The size of the preferably cut double-layer flat sample is 9cm×9cm×200m. The double-layer flat sample consists of a cable body insulation 9 and a recovery insulation 10. The treatment results of this embodiment are verified using a block-shaped flat sample. The comparative example is a block-shaped flat sample of the same size and cutting position that has not been treated by the device and method of the present invention. Interface morphology SEM, interface space charge distribution and interface normal breakdown test are used as verification basis.

[0079] The welding quality of the insulation interface of the cable molded joint can be characterized by observing the interface micromorphology using a scanning electron microscope (SEM). Figure 8 The microscopic morphology images of the interface of the comparative example and the embodiment of the present invention. In the comparative example, the size and range of the micro crack air gap defects on the interface are relatively large; in the embodiment, after plasma treatment, the size and range of the crack air gap defects on the interface are reduced, and the interface recovery quality is well improved.

[0080] The electroacoustic pulse space charge (PEA) measurement technique is used to characterize the space charge distribution on the insulation interface of cable molded joints. The average heteropolar charge density inside the cable body insulation 9 and the recovery insulation 10 reflects the charge accumulation on the sample interface. Fig. 9 The charge distribution on both sides of the insulation interface during 1600s of 50kV / mm high field polarization for the comparative example and the example. In the comparative example, obvious opposite polarity charges accumulate near the interface, and the average negative charge density in the cable body insulation 9 is -0.28C / m 3 The average positive charge density in the restored insulation 10 is 1.29C / m 3 In this embodiment, after plasma treatment, the interfacial charge accumulation phenomenon is significantly alleviated, and the average negative charge density of the cable body insulation 9 drops to -0.11C / m 3 , the average positive charge density of the restored insulation 10 drops to 0.18C / m 3 .

[0081] The electrical insulation strength of the cable molded connector insulation interface is tested using a high voltage test platform. Fig.10 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 321.72 kV / mm; in the example, after the plasma treatment, the breakdown field strength is increased to 344.17 kV / mm, and the electrical insulation strength is significantly improved.

[0082] Regarding the attached pictures: Figure 3 and Figure 4It is only a simple schematic diagram, and does not show the traces of splicing between the two semicircular ring parts, which does not mean that the two are not a spliced ​​structure.

[0083] 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 performance of a cable molded joint interface, characterized in that: include: A plasma jet reaction system and a mechanical motion control system; the plasma jet reaction system comprises a plasma generator and a gas delivery system, the plasma generator is configured to activate a gas medium in a plasma generation chamber to form plasma and spray the plasma onto a surface of a cable to be processed; the gas delivery system is used to deliver the gas medium to the plasma generation chamber; the mechanical motion control system is configured to drive the plasma generator to rotate around the circumference of the cable.

2. The device for improving the insulation performance of the cable molded joint interface according to claim 1, characterized in that: The mechanical motion control system includes a cable ring clamp, a support and a rotation drive device. The cable ring clamp includes two semicircular rings, which are detachably connected and can be buckled on the cable. The cable ring clamp is configured with an annular track. When the cable ring clamp is installed on the cable, the annular track is coaxial with the portion of the cable to be processed. The support is slidably arranged on the annular track. The rotation drive device is used to drive the support to rotate on the annular track. The plasma generator is fixedly connected to the support, and the plasma jet port of the plasma generator faces the surface of the cable to be processed.

3. The device for improving the insulation performance of the cable molded joint interface according to claim 2, characterized in that: The rotary drive device includes a stepper motor, a sun gear and a driving gear; the sun gear is sleeved and fixed on the outer side of the cable ring clamp, the stepper motor is fixedly connected to the support member, the driving gear is fixedly connected to the motor shaft of the stepper motor, and the driving gear and the sun gear are meshed for transmission.

4. The device for improving the insulation performance of the cable molded joint interface according to claim 2, characterized in that: The two semicircular ring parts are connected by a spring self-locking device; the spring self-locking device includes a lock core, a spring block, a spring and a pull rod, the surfaces of the two semicircular ring parts that are interlocked and in contact with each other are respectively a first end face and a second end face, the first end face and the second end face are both provided with two, the lock core is fixedly provided on the first end face, the bottom structure of the lock core is expanded, the spring block, the pull rod and the spring are each provided with two, a slideway is provided in the semicircular ring part on one side of the second end face, the slideway is provided parallel to the axis of the cable ring clamp, and the two The spring blocks are all arranged in the slideway and are arranged near the middle. A spring is arranged in the slideway on the opposite side of the two spring blocks. The spring gives the two spring blocks an elastic force to approach each other. Under normal conditions, the distance between the two spring blocks is smaller than the size of the bottom structure of the lock core. The opposite side of the spring blocks is provided with an inclined guide surface. The distance between the two guide surfaces increases from the bottom to the top. One end of the pull rod is fixedly connected to the spring block, and the other end extends along the slideway and extends from the side of the semicircular ring member. When the two semicircular ring members are buckled on the outside of the cable and approach each other, the lock core can enter between the two spring blocks and achieve locking, and the lock core can be unlocked by pulling the spring blocks in opposite directions by the pull rod.

5. The device for improving the insulation performance of the cable molded joint interface according to claim 2, characterized in that: It also includes a horizontal telescopic rod and an inclined telescopic rod, one end of the horizontal telescopic rod is fixedly connected to the side of the support member facing the part to be processed, the other end is fixedly connected to one end of the inclined telescopic rod, and the other end of the inclined telescopic rod is fixedly connected to the plasma generator.

6. The device for improving the insulation performance of the cable molded joint interface according to claim 1, characterized in that: The plasma generator comprises a high-voltage needle electrode, a grounding ring electrode, a nanosecond pulse power supply and a quartz glass tube; the plasma generating chamber is formed in the quartz glass tube, the high-voltage needle electrode is connected to the nanosecond pulse power supply and one end thereof extends from the top of the quartz glass tube into the quartz glass tube, the grounding ring electrode is sleeved on the outer circumference of the quartz glass tube below the high-voltage needle electrode, the grounding ring electrode is grounded, the nanosecond pulse power supply applies voltage to the high-voltage needle electrode, the outer wall of the quartz glass tube serves as a barrier medium for discharge, and a jet-like plasma jet is generated.

7. The device for improving the insulation performance of the cable molded joint interface according to claim 6, characterized in that: The gas delivery system comprises a high-purity argon gas bottle and a flow meter. The high-purity argon gas bottle is connected to the quartz glass tube through a gas pipe, and the flow meter is arranged on the gas pipe.

8. The device for improving the insulation performance of the cable molded joint interface according to claim 7, characterized in that: The diameter of the quartz glass tube is 4 cm and the length is 20 cm. The diameter of the high-voltage needle electrode is 1 cm and the length is 30 cm, and the lower end is 6 cm away from the lower end of the quartz glass tube. The grounding ring electrode is tightly attached to the outer wall of the quartz glass tube and fixed at 3 cm away from the lower end of the high-voltage needle electrode.

9. A method for improving the insulation performance of a cable molded joint interface, characterized in that: include: The cable is treated by using the device for improving the insulation performance of the cable molded joint interface according to any one of claims 1 to 8; the steps are as follows: S1: According to the manufacturing process of submarine cable molded joints, after welding the cable conductor and wrapping the conductor shielding layer, wipe the insulation surface of the cable body with clean alcohol test paper; S2: Install the mechanical motion control system on the cable; S3: start the plasma jet reaction system; S4: The mechanical motion control system drives the plasma generator to rotate unidirectionally or reciprocatingly; S5: After the treatment is completed, the mechanical motion control system and the plasma jet reaction system are turned off; the position of the plasma generator is adjusted to move the set distance along the inclined surface of the cable body insulation, and steps S3 and S4 are repeated until the entire area of ​​the cable body insulation is treated; S6: Remove the mechanical motion control system and, according to the cable molded connector insulation preparation process, cast the recovery insulation on the cable body insulation to restore the insulation.

10. The method for improving the insulation performance of the cable molded joint interface according to claim 9, characterized in that: Before actual use, multiple tests were conducted to determine the time for interface treatment and the optimal working parameters for the plasma jet reaction system and mechanical motion control system.

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