A new process for manufacturing a middle joint of a high-voltage cable

Abstract

The application discloses a new-process middle-high voltage cable intermediate joint, relates to the technical field of middle-high voltage cable intermediate joints, and comprises an upper rubber sleeve, the rear end of the upper rubber sleeve is fixedly connected with an upper connecting ring, the inner edge of the upper connecting ring is fixedly connected with a main adhesive pipe, the front end of the main adhesive pipe is fixedly connected with an upper clamping ring and sleeved with an upper threaded ring, and the outer extension of the upper threaded ring is fixedly connected with a main threaded arc plate. By adopting the new connection process, the application avoids the fire, explosion and other safety accidents caused by the use of gunpowder in traditional hot melting welding, can be safely constructed in a closed space such as a tunnel or a subway, reduces the threat to the health of construction personnel, and can adapt to various complex construction environments, especially in a space with more closed and limited conditions, such as a tunnel and a subway. The new process simplifies construction steps, improves construction efficiency, and makes the installation process faster and more convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medium and high voltage cable intermediate joint, in particular to a new process of medium and high voltage cable intermediate joint. BACKGROUND

[0002] At present, in the process of cable fusion joint construction and installation, copper core connection often adopts hot melting welding method. This process needs to use gunpowder as primer to ignite welding powder when operating, and copper core is melted through exothermic combustion to realize connection. Although hot melting welding can ensure the firmness of copper core connection to a certain extent, it has many safety hazards and use limitations.

[0003] In relatively closed space environment such as tunnel and subway, due to poor air circulation, smoke, harmful gas and high temperature flame generated after ignition of gunpowder not only seriously threaten the health of construction personnel, but also may cause fire, explosion and other safety accidents. In addition, there are strict safety regulations and restrictions in these closed spaces, so that the hot melting welding process is difficult to carry out smoothly in these specific environments, and even is prohibited to use, which undoubtedly brings great inconvenience to the construction and installation of cable intermediate joint, and affects the progress and quality of the project. Through in-depth analysis of the failure causes of medium and high voltage cable accessory intermediate joint, it is found that the decrease of insulation performance is the main factor leading to joint failure, which accounts for more than 95%, and the quality problem caused by copper core welding is relatively small.

[0004] In the process design of cable intermediate joint, since the influence of copper core welding on the overall quality is small, other safer and more convenient connection methods can be considered to replace the traditional hot melting welding process, while ensuring that the melting process of the insulation part is retained to meet the requirements of normal operation of the cable on the insulation performance. Considering the above situation, although the traditional cable fusion process has its characteristics in copper core connection, the safety problem in specific environment limits its application. Simply relying on cable crimping method can avoid the safety hazards brought by hot melting welding, but there may be certain deficiencies in the firmness and conductivity of copper core connection.

[0005] Therefore, a new process joint that can make up for the defects of cable fusion process and combine the advantages of cable crimping is particularly necessary. This new process should have the characteristics of convenient and fast construction, be able to adapt to various complex construction environments, especially closed spaces such as tunnels and subways. At the same time, it has advantages in cost, can reduce the cost of engineering construction and maintenance, and improve economic benefits. SUMMARY

[0006] In order to achieve the above object, the application provides a new process middle joint of high-voltage cable, which comprises an upper rubber sleeve, a rear end of the upper rubber sleeve is fixedly connected with an upper connecting ring, an inner edge of the upper connecting ring is fixedly connected with a main adhesive pipe, a front end of the main adhesive pipe is fixedly connected with an upper clamping ring and sleeved with an upper threaded ring, an outer extension of the upper threaded ring is fixedly connected with a main threaded arc plate, a middle part of adjacent main threaded arc plates is inserted with a secondary threaded arc plate, a bottom end of the secondary threaded arc plate is fixedly connected with a lower threaded ring and internally clamped with a lower clamping ring, an inner side of the lower clamping ring is fixedly connected with a secondary adhesive pipe, a front end of the secondary adhesive pipe is fixedly connected with a lower connecting ring of which an edge is fixedly connected with a lower rubber sleeve, middle parts of the main threaded arc plate and the secondary threaded arc plate are respectively penetrated with a first telescopic rod and a second telescopic rod, a bottom end of the first telescopic rod is sequentially fixedly connected with a first insulation sleeve and a first fixed pipe, a bottom end of the second telescopic rod is sequentially fixedly connected with a second insulation sleeve and a second fixed pipe.

[0007] In one example, the upper rubber sleeve is located outside the main adhesive pipe, the lower rubber sleeve is located outside the secondary adhesive pipe, end parts of the upper rubber sleeve and the lower rubber sleeve are hot melt connected, inner sides of the main adhesive pipe and the secondary adhesive pipe are hot melt connected on the outer side of the cable.

[0008] In one example, a plurality of main threaded arc plates are uniformly distributed on the outer side of the upper threaded ring, a plurality of secondary threaded arc plates are uniformly distributed on the outer side of the lower threaded ring, and the main threaded arc plates and the secondary threaded arc plates are alternately inserted.

[0009] In one example, the outer side of the secondary threaded arc plate is threadedly connected with a secondary fastening nut, the outer side of the main threaded arc plate is threadedly connected with a main fastening nut, middle parts of the main threaded arc plate and the secondary threaded arc plate are provided with circular holes, and the first telescopic rod and the second telescopic rod are located in the middle parts of the circular holes of the main threaded arc plate and the secondary threaded arc plate.

[0010] In one example, a copper wire is arranged in the middle part of the second insulation sleeve and the second fixed pipe, the first insulation sleeve and the second insulation sleeve are located on the outer sides of the first fixed pipe and the second fixed pipe, and end parts of the first fixed pipe and the second fixed pipe are provided with rectangular grooves.

[0011] In one example, a main limiting spring is sleeved on the middle part of the first telescopic rod, a main extrusion nut is threadedly connected with the bottom end of the first telescopic rod and penetrated with a main extrusion plate, a secondary limiting spring is sleeved on the middle part of the second telescopic rod, a secondary extrusion nut is threadedly connected with the bottom end of the second telescopic rod and penetrated with a secondary extrusion plate.

[0012] In one example, the first insulation sleeve insulates the first fixed pipe, the second insulation sleeve insulates the second fixed pipe, and the number of the first fixed pipe and the second fixed pipe is same as that of the copper wire of the cable.

[0013] In one example, the end portions of the main extrusion plate and the auxiliary extrusion plate press the copper wires, and the end portions of the two copper wires are located in the middle portions of the first fixed tube and the second fixed tube, and the copper wire end portions are first crimped.

[0014] In one example, the top ends of the first telescopic rod and the second telescopic rod are located in the middle portions of the main fastening nut and the auxiliary fastening nut, and the bottom ends of the first telescopic rod and the second telescopic rod are conical.

[0015] The intermediate joint of the medium and high voltage cable provided by the application can bring the following beneficial effects:

[0016] 1. The intermediate joint of the medium and high voltage cable provided by the application can adapt to various complex construction environments, especially in spaces with more closed and limited conditions, such as tunnels and subways, and the new process simplifies the construction steps, improves the construction efficiency, and makes the installation process faster and more convenient.

[0017] 2. The intermediate joint of the medium and high voltage cable provided by the application can effectively protect the insulation performance of the cable, and the use of the upper rubber sleeve and the lower rubber sleeve for hot melt connection and the staggered insertion design of the main threaded arc plate and the auxiliary threaded arc plate ensure the firmness of the joint part, and the new process has advantages in cost, which can reduce the cost of engineering construction and maintenance and improve the overall economic benefit.

[0018] 3. The intermediate joint of the medium and high voltage cable provided by the application can reduce the quality problems caused by copper core welding, thereby reducing the incidence of joint failure, and the durability and anti-aging characteristics of the new process help to prolong the service life of the intermediate joint of the medium and high voltage cable, and the new process reduces pollution to the environment because it no longer needs to use the traditional hot melt welding method that may produce harmful gases, and the structure of the intermediate joint of the medium and high voltage cable is reasonable, which is convenient for daily inspection and maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings described herein are used to provide further understanding of the application, and form a part of the application. The illustrative embodiments of the application and their descriptions are used to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0020] Figure 1 It is the overall structure schematic diagram of the intermediate joint of the medium and high voltage cable of the new process of the application.

[0021] Figure 2The figure is a schematic diagram of the explosion structure of the intermediate joint of the middle and high voltage cable according to the new process.

[0022] Figure 3 The figure is a schematic diagram of the internal structure of the intermediate joint of the middle and high voltage cable according to the new process.

[0023] Figure 4 The figure is a schematic diagram of the thread structure of the intermediate joint of the middle and high voltage cable according to the new process.

[0024] Figure 5 The figure is a schematic diagram of the middle structure of the intermediate joint of the middle and high voltage cable according to the new process.

[0025] Figure 6 The figure is a schematic diagram of the limiting tube structure of the intermediate joint of the middle and high voltage cable according to the new process.

[0026] The figure is a schematic diagram of the limiting tube structure of the intermediate joint of the middle and high voltage cable according to the new process. DETAILED DESCRIPTION

[0027] In order to more clearly and completely illustrate the technical solutions of the present application, the present application will be further described below with reference to the accompanying drawings.

[0028] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0029] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0030] In the present application, unless specifically defined otherwise and limited, the terms "mount", "connect", "connection", "fixed", and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection, and can also be communication; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] In the present application, unless specifically defined otherwise and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. In the description of the specification, the description referring to the terms "one scheme", "some schemes", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the scheme or example are included in at least one scheme or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same scheme or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more schemes or examples in a suitable manner.

[0032] Please refer to Figures 1-6 The present application proposes the installation process of the intermediate joint of the medium and high voltage cable, which needs to follow the standardized process of "insulation pretreatment → conductor connection → mechanical fixation → sealing treatment → overall test", to ensure the cooperation of each component, realize the double standard of electrical performance and mechanical strength, use a manual straightener to straighten the exposed copper conductor, remove the insulation layer of 20mm at the end of the conductor, use a stepped stripping method to form a 30° chamfer, reduce the electric field stress concentration, select a suitable hexagonal crimping die according to the cross-sectional area of the conductor, the die material is high-strength aluminum alloy, the crimping sequence follows the principle of from the middle to the two ends, the distance between adjacent crimping positions is ≥20mm, and the crimping depth needs to reach the die calibration value.

[0033] The fixed tube is positioned, the first fixed tube 23 and the second fixed tube 26 are respectively sleeved on the copper conductor end to be connected, the conductor insertion depth is ensured to reach 2 / 3 of the length of the fixed tube, the rectangular slot at the end of the fixed tube has a width of 5 mm and a depth of 3 mm, and needs to be aligned with the conductor crimping part, so that subsequent mechanical extrusion fixation and insulation sleeve wrapping are facilitated; the silicon rubber insulation sleeve is used to wrap the fixed tube, the wrapping length needs to exceed the end of the fixed tube by 20 mm, an umbrella skirt-shaped insulation structure is formed, the creepage distance is improved, and silicon grease is coated between the insulation sleeve and the fixed tube to eliminate air gap and enhance the interface bonding strength; the first telescopic rod 13 is installed, the first telescopic rod is inserted through the circular hole of the main threaded arc plate 6, the top end is screwed into the internal thread hole of the main fastening nut 4, and the bottom end conical structure is aligned with the top center of the first fixed tube 23; the main limiting spring 16 is sleeved on the middle part of the telescopic rod, and the pre-compression amount is 10 mm, so that the initial axial pressure is provided; the main extrusion nut 17 is adjusted, the torque wrench is used to tighten the main extrusion nut in the clockwise direction, the torque value is set to 80 N·m, the copper conductor at the top of the fixed tube is uniformly crimped by the main extrusion plate 18, the compression amount of the main limiting spring is observed during the extrusion process, and the final compression amount is ensured to reach 20 mm, so that the mechanical strength of the conductor connection is guaranteed; the second telescopic rod 22 is synchronously operated, and the installation and adjustment processes of the secondary limiting spring 24, the secondary extrusion nut 25 and the secondary extrusion plate 21 of the secondary extrusion mechanism are consistent with those of the main extrusion mechanism, and it is necessary to ensure that the pressures on both sides are balanced.

[0034] The main threaded arc plate 6 and the secondary threaded arc plate 7 are assembled, the number of main threaded arc plates on the upper threaded ring 14 is 6-8, the number of secondary threaded arc plates on the lower threaded ring 11 is adjusted according to the cable specification, and the secondary threaded arc plates are inserted according to the staggered angle, so that a honeycomb-shaped mechanical locking structure is formed, the main fastening nut 4 and the secondary fastening nut 5 adopt M12 specification fine thread, and are tightened in three stages, the upper clamping ring is sleeved into the front end of the main adhesive tube 9, and the mechanical clamping is formed through the annular groove and the main adhesive tube, and the lower clamping ring 12 and the secondary adhesive tube 10 are installed in the same way.

[0035] The main adhesive tube 9 and the secondary adhesive tube 10 adopt EVA hot melt adhesive material, the inside is pre-fabricated with a spiral hot melt adhesive strip with a width of 5 mm and a thickness of 1.5 mm, the outer surface of the adhesive tube is uniformly heated by using a hot air gun with a temperature setting of 130±5℃, the duration is 30-60 seconds, the adhesive tube is quickly pressed and covered on the cable insulation layer after the hot melt adhesive is melted, the cooling and solidification time is ≥10 minutes, and the thickness of the adhesive layer is detected by using an ultrasonic thickness gauge after hot melt connection.

[0036] The upper rubber sleeve 1 and the lower rubber sleeve 2 are made of EPDM material, the groove of the rubber sleeve is heated by a special hot melting mold, the heating time is 4-6 minutes, until the end surface is molten to a mirror state, the upper and lower rubber sleeves are quickly aligned and pressed, the pressure maintaining time is 15-20 minutes, and after cooling, a whole sealing structure is formed, after the butt joint is completed, the welding seam is detected by coloring penetration method, and no bubble and crack are qualified, in the transition area of the rubber sleeve and the cable insulation layer, a stress cone is formed by molding with a mold, the electric field strength gradient is reduced, the half-conductive layer is embedded in the stress cone, and the overlap length of the cable shielding layer is greater than or equal to 50 mm, so that the electric field is uniformly distributed, the self-adhesive rubber belt with a thickness of 1 mm and the waterproof sealing cement are sequentially wound outside the rubber sleeve, the overlap rate is greater than or equal to 50%, the outermost layer is covered with a PVC protective belt, the overlap width is 15-20 mm, and a complete moisture-proof and waterproof system is formed.

[0037] In the embodiment, the upper rubber sleeve 1 is located outside the main bonding pipe 9, the lower rubber sleeve 2 is located outside the auxiliary bonding pipe 10, the end portions of the upper rubber sleeve 1 and the lower rubber sleeve 2 are connected by hot melting, the sealing property and stability are ensured, the design not only provides additional insulation protection, but also increases the mechanical strength of the joint part, the inner side surface of the main bonding pipe 9 is connected with the outer side surface of the cable by hot melting, a tight bonding layer is formed, the auxiliary bonding pipe 10 is also connected with the outer side surface of the cable by hot melting technology, and good electrical insulation performance is ensured, the upper connecting ring 8 is fixedly connected to the upper rubber sleeve 1, and provides support and positioning for the whole structure, the lower connecting ring 3 is fixedly connected to the lower rubber sleeve 2, cooperates with the upper connecting ring 8, and ensures the integrity of the structure, the upper clamping ring 15 is fixedly connected to the front end of the main bonding pipe 9, and is used for connection with other components, and the lower clamping ring 12 is fixedly connected to the front end of the auxiliary bonding pipe 10, and is used in cooperation with the upper clamping ring 15.

[0038] The upper threaded ring 14 is sleeved on the upper clamping ring 15 and is inserted with the adjacent auxiliary threaded arc plate 7 through the main threaded arc plate 6, the lower threaded ring 11 is sleeved on the lower clamping ring 12 and is similar to the design of the upper threaded ring 14 but is used for connecting the structure below, the main threaded arc plate 6 and the auxiliary threaded arc plate 7 are inserted with each other in an interlaced mode, and the overall stability of the joint is enhanced, the auxiliary fastening nut 5 is threadedly connected to the outer side of the auxiliary threaded arc plate 7, the main fastening nut 4 is threadedly connected to the outer side of the main threaded arc plate 6, and the position of the threaded arc plate can be adjusted by rotating the nut, so that the tightness of the joint is accurately controlled.

[0039] The first telescopic rod 13 and the second telescopic rod 22 pass through the round holes of the main threaded arc plate 6 and the auxiliary threaded arc plate 7 respectively, and are located at the middle part of the main fastening nut 4 and the auxiliary fastening nut 5 at the top end, the telescopic rod is designed to allow length adjustment according to actual needs, to adapt to different specifications of cables, the first insulation sleeve 19 insulates the first fixed tube 23, and the second insulation sleeve 20 insulates the second fixed tube 26, the double-layer insulation design effectively prevents current leakage and improves safety, the number of the first fixed tube 23 and the second fixed tube 26 is the same as that of the copper wire of the cable, so that each copper wire is fully fixed, and the end part of the fixed tube is provided with a rectangular slot, so as to facilitate the insertion and fixation of the copper wire, the end part of the first extrusion plate 18 and the second extrusion plate 21 presses the copper wire, so as to ensure good contact between the copper wire and the fixed tube, the design improves the conductivity and reduces energy loss.

[0040] The main limiting spring 16 is sleeved at the middle part of the first telescopic rod 13, and the auxiliary limiting spring 24 is sleeved at the middle part of the second telescopic rod 22, the springs are used for limiting the movement range of the telescopic rod, so as to ensure the stability of the structure, the main extrusion nut 17 is threadedly connected at the bottom end of the first telescopic rod 13 and penetrates the main extrusion plate 18, the auxiliary extrusion nut 25 is threadedly connected at the bottom end of the second telescopic rod 22 and penetrates the auxiliary extrusion plate 21, by rotating the nut, the position of the extrusion plate can be adjusted, so as to change the extrusion degree of the copper wire, the copper wire is arranged at the middle part of the second insulation sleeve 20 and the second fixed tube 26, and the first insulation sleeve 19 and the second insulation sleeve 20 are located outside the first fixed tube 23 and the second fixed tube 26, in the installation process, the end part of the copper wire is first crimped, then is placed into the fixed tube, and finally is fixed through the extrusion plate and the nut.

[0041] First, the upper rubber sleeve 1 and the lower rubber sleeve 2 are respectively sleeved on both ends of the cable, then the main bonding pipe 9 and the auxiliary bonding pipe 10 are connected with the outer side of the cable through hot melt technology, the upper connecting ring 8 and the lower connecting ring 3 are respectively fixed on the upper rubber sleeve 1 and the lower rubber sleeve 2, the upper clamping ring 15 and the lower clamping ring 12 are respectively fixed on the front end of the main bonding pipe 9 and the auxiliary bonding pipe 10, the upper threaded ring 14 and the lower threaded ring 11 are respectively sleeved on the upper clamping ring 15 and the lower clamping ring 12, next, the main threaded arc plate 6 and the auxiliary threaded arc plate 7 are inserted into each other, and the position is adjusted by rotating the main fastening nut 4 and the auxiliary fastening nut 5, the first telescopic rod 13 and the second telescopic rod 22 are respectively penetrated through the round holes of the main threaded arc plate 6 and the auxiliary threaded arc plate 7, the first insulation sleeve 19 and the second insulation sleeve 20 are respectively sleeved on the first telescopic rod 13 and the second telescopic rod 22, the first fixed pipe 23 and the second fixed pipe 26 are respectively inserted into the first insulation sleeve 19 and the second insulation sleeve 20, and the copper wire is placed in the fixed pipe, the first extrusion plate 18 and the second extrusion plate 21 are respectively placed at the end of the copper wire, and are fixed through the main extrusion nut 17 and the auxiliary extrusion nut 25, whether all the components are firmly installed is checked, and it is ensured that the insulation performance and the mechanical strength of the joint meet the requirements.

[0042] Of course, the present application can have other various embodiments, and other embodiments obtained by those skilled in the art based on the embodiments without any creative labor are within the scope of the present application.

Claims

1. A new process for a medium-high voltage cable joint, characterized in that, The utility model provides an improved cable fixing device, which comprises an upper rubber sleeve (1), a rear end of the upper rubber sleeve (1) is fixedly connected with an upper connecting ring (8), an inner edge of the upper connecting ring (8) is fixedly connected with a main adhesive pipe (9), a front end of the main adhesive pipe (9) is fixedly connected with an upper clamping ring (15) and sleeved with an upper threaded ring (14), an outer extension of the upper threaded ring (14) is fixedly connected with a main threaded arc plate (6), a middle part of adjacent main threaded arc plates (6) is inserted with a secondary threaded arc plate (7), a bottom end of the secondary threaded arc plate (7) is fixedly connected with a lower threaded ring (11) and internally clamped with a lower clamping ring (12), an inner side of the lower clamping ring (12) is fixedly connected with a secondary adhesive pipe (10), a front end of the secondary adhesive pipe (10) is fixedly connected with a lower connecting ring (3) of which an edge is fixedly connected with a lower rubber sleeve (2), middle parts of the main threaded arc plate (6) and the secondary threaded arc plate (7) are respectively penetrated with a first telescopic rod (13) and a second telescopic rod (22), a bottom end of the first telescopic rod (13) is sequentially fixedly connected with a first insulating sleeve (19) and a first fixed pipe (23), a bottom end of the second telescopic rod (22) is sequentially fixedly connected with a second insulating sleeve (20) and a second fixed pipe (26).

2. A new process for manufacturing a middle high voltage cable joint according to claim 1, characterized in that, The upper rubber sleeve (1) is located on the outer side of the main adhesive pipe (9), the lower rubber sleeve (2) is located on the outer side of the secondary adhesive pipe (10), the end parts of the upper rubber sleeve (1) and the lower rubber sleeve (2) are hot melt connected, and the inner sides of the main adhesive pipe (9) and the secondary adhesive pipe (10) are hot melt connected on the outer side of the cable.

3. A new process for manufacturing a middle high voltage cable joint according to claim 1, characterized in that, A plurality of main threaded arc plates (6) are uniformly distributed on the outer side of the upper threaded ring (14), a plurality of secondary threaded arc plates (7) are uniformly distributed on the outer side of the lower threaded ring (11), and the main threaded arc plates (6) and the secondary threaded arc plates (7) are alternately inserted.

4. A new process for manufacturing a middle high voltage cable joint according to claim 1, characterized in that, The outer side of the secondary threaded arc plate (7) is threadedly connected with a secondary fastening nut (5), the outer side of the main threaded arc plate (6) is threadedly connected with a main fastening nut (4), the middle parts of the main threaded arc plate (6) and the secondary threaded arc plate (7) are provided with circular holes, and the first telescopic rod (13) and the second telescopic rod (22) are located in the middle parts of the circular holes of the main threaded arc plate (6) and the secondary threaded arc plate (7).

5. A new process for manufacturing a medium-high voltage cable joint according to claim 1, characterized in that, Copper wires are arranged in the middle parts of the second insulating sleeve (20) and the second fixed pipe (26), the first insulating sleeve (19) and the second insulating sleeve (20) are located on the outer sides of the first fixed pipe (23) and the second fixed pipe (26), and rectangular grooves are formed in the end parts of the first fixed pipe (23) and the second fixed pipe (26).

6. A new process for manufacturing a medium-high voltage cable joint according to claim 1, characterized in that, A main limiting spring (16) is sleeved on the middle part of the first telescopic rod (13), a main extrusion nut (17) is threadedly connected to the bottom end of the first telescopic rod (13) and penetrated with a main extrusion plate (18), a secondary limiting spring (24) is sleeved on the middle part of the second telescopic rod (22), a secondary extrusion nut (25) is threadedly connected to the bottom end of the second telescopic rod (22) and penetrated with a secondary extrusion plate (21).

7. A new process for manufacturing a middle high voltage cable joint according to claim 1, characterized in that, The first insulation sleeve (19) insulates the first fixed tube (23), the second insulation sleeve (20) insulates the second fixed tube (26), the number of the first fixed tube (23) and the second fixed tube (26) is same as the copper wire of the cable.

8. A new process for manufacturing a middle high voltage cable joint according to claim 6, characterized in that, The end of the main extrusion plate (18) and the auxiliary extrusion plate (21) presses the copper wire, the end of the two copper wires is located in the middle of the first fixed tube (23) and the second fixed tube (26), and the copper wire end is pressed first.

9. A new process for manufacturing a middle high voltage cable joint according to claim 4, characterized in that, The top end of the first telescopic rod (13) and the second telescopic rod (22) is located in the middle of the main fastening nut (4) and the auxiliary fastening nut (5), and the bottom end of the first telescopic rod (13) and the second telescopic rod (22) is conical.

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