Manufacturing method of 35kV and below polypropylene cable terminal and polypropylene cable terminal

Abstract

The invention discloses a manufacturing method of a 35kV and below polypropylene cable terminal and the polypropylene cable terminal, and the method comprises the steps: carrying out the stripping operation of the end part of a cable, and exposing a cable conductor and a cable insulating layer; winding the polypropylene insulating strip back and forth from the notch of the insulating shielding layer to the cable conductor for multiple times; a stress cone sleeves the outer sides of the insulation shielding layer and the polypropylene insulation strip; a polypropylene insulating strip is wound on the outer side of the stress cone back and forth in the direction from the insulating shielding layer to the cable conductor to be fusiform; carrying out heating and heat preservation on the polypropylene insulating strip, and welding the cable insulating layer, the insulating shielding layer, the stress cone and the polypropylene insulating strip into a whole; and installing a multi-umbrella-shaped rubber sleeve and a cable terminal. According to the polypropylene cable terminal obtained by the method, the sliding surface between the cable accessory and the cable end part can be removed, and the problems of discharge caused by an air gap in the sliding surface due to reduction of the attaching force and reduction of the electrical performance caused by aging of the cable accessory in the later period are solved.

Description

Technical Field

[0001] The invention relates to the technical field of cable installation, and in particular to a method for manufacturing a 35 kV or lower polypropylene cable terminal and a polypropylene cable terminal. Background Art

[0002] Cross-linked polyethylene is widely used in power cable materials because of its good electrical properties and heat resistance. However, when cross-linked polyethylene cables reach the end of their service life, they are difficult to degrade or recycle due to their stable molecular structure and the fact that they are thermosetting materials, which has a negative impact on the environment. Therefore, environmentally friendly polypropylene cables are used, and the installation technology of related cable accessories has also become a key research object.

[0003] At present, cold-shrink prefabricated rubber accessories are used to make polypropylene cable terminals. They are prefabricated in the factory, and then the inner diameter is expanded by using a pull-out expansion tube through the expansion technology. The cold-shrink prefabricated rubber accessories are inserted into the cable end for easy use on site. Since the cold-shrink prefabricated rubber accessories have a certain elasticity, they can fit on the cable end. There is a rubber stress cone inside the cold-shrink prefabricated rubber accessory, which fits with the cut of the outer semi-conductive layer of the cable, and can homogenize the concentrated electric field at the cut to avoid cable operation failure caused by electric field concentration. The polypropylene cable terminals made in the prior art have the following shortcomings:

[0004] When the cold-shrink prefabricated rubber accessories are in use, they are attached to the cable ends. There is a slip surface between the cold-shrink prefabricated rubber accessories and the cable ends. If conductive dust and other impurities are left on the slip surface when the cold-shrink prefabricated rubber accessories are installed, the polypropylene cable terminal is prone to gradually produce creepage marks at the semi-conductive cutout outside the cable during long-term operation, which eventually leads to cable failure. At the same time, since the life of the cold-shrink prefabricated rubber accessories is shorter than that of the cable, especially outdoors, they are affected by various radiations, which makes the cold-shrink prefabricated rubber accessories more prone to aging. The power cable operation and maintenance personnel need to regularly replace the cable accessories that have been in operation for a long time. If the replacement is not timely, the electrical performance of the cold-shrink prefabricated rubber accessories will decrease after aging, and they are easy to deform, resulting in insufficient adhesion at the slip surface. The cold-shrink prefabricated rubber accessories will slide, causing cable failures, and their maintenance costs are high. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems and provide a method for manufacturing a 35kV and below polypropylene cable terminal. The polypropylene cable terminal obtained by the above-mentioned manufacturing method can remove the slippery surface between the cable accessories and the cable end, avoid the phenomenon of creepage marks at the semi-conducting cutout outside the cable, solve the problem of discharge caused by air gaps on the slippery surface due to decreased adhesion, and solve the problem of electrical performance degradation caused by aging of cable accessories in the later stage, which can effectively reduce the later maintenance costs.

[0006] Another object of the present invention is to provide a polypropylene cable terminal manufactured by a 35kV and below polypropylene cable terminal manufacturing method.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for manufacturing a 35 kV or lower polypropylene cable terminal comprises the following steps:

[0009] (1) Cable stripping pretreatment:

[0010] The cable end is stripped to expose the cable conductor and the cable insulation layer at the cable end. The material of the cable insulation layer is polypropylene.

[0011] (2) Cable and stress cone winding treatment:

[0012] (2.1) Wrap the polypropylene insulating tape back and forth multiple times from the cutout of the insulating shielding layer toward the cable conductor, so that the polypropylene insulating tape covers the cutout of the insulating shielding layer and the cable insulating layer near the cutout;

[0013] (2.2) Place the stress cone on the outside of the insulation shielding layer and the polypropylene insulation tape;

[0014] (2.3) Then, the polypropylene insulating tape is wound back and forth from the insulating shielding layer toward the cable conductor on the outside of the stress cone until it becomes a shuttle shape; thereby, the polypropylene insulating tape covers the insulating shielding layer, the stress cone and the cable insulating layer;

[0015] (3) Heating and welding treatment of cable ends:

[0016] The shuttle-shaped polypropylene insulating tape is heated and insulated, and the cable insulating layer, the insulating shielding layer, the stress cone and the polypropylene insulating tape are welded together; the polypropylene insulating tape is melted to form a recovery insulating layer;

[0017] (4) Multi-umbrella rubber sleeve and cable terminal installation:

[0018] Install a multi-umbrella-shaped rubber sleeve, which covers the outer sides of the insulating shielding layer, the recovery insulating layer and the cable insulating layer; and install the cable terminal at the end of the cable conductor.

[0019] In a preferred embodiment of the present invention, in step (1), the specific steps of stripping the cable end are:

[0020] Remove the outer structure at the end of the cable to expose the insulation shielding layer; sequentially remove a part of the insulation shielding layer and the cable insulation layer to expose the cable conductor and the cable insulation layer; the outer structure includes a cable outer sheath and a metal sheath, and the metal sheath is located inside the cable outer sheath; after exposing the cable conductor and the cable insulation layer, chamfer the cut of the insulation shielding layer with a tool and perform a grinding treatment to make the cut of the insulation shielding layer round and without steps, and clean the cut.

[0021] Preferably, in step (2), the shape of the stress cone is a "son" shape, and the stress cone includes a straight section and a curved arc section; the straight section of the stress cone covers the outside of the insulation shielding layer and the polypropylene insulating tape; the curved arc section of the stress cone faces the cable conductor. The stress cone can equalize the electric field concentrated at the cut, avoiding cable operation failures caused by electric field concentration.

[0022] Preferably, the material of the insulation shielding layer contains polypropylene. In step (2), the stress cone is pre-fabricated in the factory. The insulation shielding layer material is extruded, heated, and branched through an extruder; the insulation shielding layer material is squeezed into the stress cone forming die, and the temperature of the stress cone is controlled by controlling the forming temperature. After cooling, the stress cone is taken out of the stress cone forming die. The purpose is that the stress cone is made of the insulation shielding layer material, that is, the materials of the insulation shielding layer and the stress cone are the same, both containing polypropylene. During the heat fusion treatment, since the material of the polypropylene insulating tape is polypropylene, the molten polypropylene insulating tape can be connected to the surface of the stress cone and the surface of the insulation shielding layer to form an integral body, preventing the existence of a sliding surface between the stress cone, the insulation shielding layer, and the cable insulation layer, and not damaging the original cable structure.

[0023] Preferably, between step (2) and step (3), the following steps are further included:

[0024] Installation of heating auxiliary materials at the cable end: Install heating auxiliary materials outside the polypropylene insulating tape wound to form a spindle-shaped structure, and install a temperature sensor on the heating auxiliary materials;

[0025] Between step (3) and step (4), the following steps are further included:

[0026] Removal of heating auxiliary materials at the cable end: After the heat preservation is completed, wait for the cable end to cool to room temperature, remove the heating auxiliary materials, and expose the restored insulation layer. By setting the heating auxiliary materials, protection can be provided during the heating of the polypropylene insulating tape. The temperature sensor is used to detect the heating temperature at the cable end and monitor the heating temperature in real time.

[0027] Preferably, the heating auxiliary materials include rubber soft film, tin foil, polyimide tape, silicone rubber heating tape and thermal insulation cloth; when installing the heating auxiliary materials, the rubber soft film, tin foil, polyimide tape, silicone rubber heating tape and thermal insulation cloth are installed in sequence on the outside of the polypropylene insulating tape that forms a shuttle structure after winding, and a temperature sensor is installed on the silicone rubber heating tape.

[0028] Preferably, after the heating auxiliary material at the cable end is removed, the following steps are also included:

[0029] Cable end appearance treatment: Grind the surface of the restored insulation layer to make a uniform transition between the restored insulation layer and the cable insulation layer and the insulating shielding layer, clean the dust on the surface of the restored insulation layer, and keep the surface of the restored insulation layer clean.

[0030] Preferably, in step (3), a heating mold is used to heat and keep the shuttle-shaped polypropylene insulating tape warm; the heating mold includes an upper heating module and a lower heating module; the upper heating module and the lower heating module both include an inner mold and an outer mold, a mold cavity is provided between the two inner molds, the mold cavity cooperates with the shuttle-shaped polypropylene insulating tape, and the outer film is arranged on the outer side of the inner mold; a plurality of heating units are provided on the inner mold, and the plurality of heating units are arranged along the outer contour of the shuttle-shaped polypropylene insulating tape; each heating unit independently controls its heating temperature. In the above structure, a plurality of heating units are arranged along the outer contour of the polypropylene insulating tape of the shuttle-shaped structure, that is, a plurality of heating units are arranged in a shuttle shape along the axial direction of the inner mold, and each heating unit is at the same distance from the outer surface of the polypropylene insulating tape of the shuttle-shaped structure. Since the polypropylene insulating tape is in the shape of a shuttle, the heating units are also arranged in a shuttle shape. Since the polypropylene insulating tape is in the shape of a shuttle and the stress cone is in the shape of an "er", the radial thickness of the polypropylene insulating tape is different. If the temperature control heating equipment in the prior art is used for heating, the heating of each area of ​​the polypropylene insulating tape is uneven, so that after the polypropylene insulating tape is melted, the flow is disordered and the distribution is uneven. The connection with the cable insulation layer, the insulation shielding layer and the stress cone is not uniform and the blending is uneven, which may cause the thicker part to not be completely melted and the thicker part to be thicker. The heat is transferred to the cable insulation layer, insulation shielding layer or stress cone for a long time with a small degree, resulting in the complete destruction of the structure of the cable insulation layer, insulation shielding layer and stress cone, affecting the quality of heating and welding, and further affecting the quality of the polypropylene cable terminal; in the above structure, by setting a plurality of heating units, each heating unit can be independently controlled, the heating unit corresponding to the smaller thickness of the polypropylene insulation tape reduces the heating temperature, and the heating unit corresponding to the larger thickness of the polypropylene insulation tape increases the heating temperature, so that the heat of each area of ​​the polypropylene insulation tape is evenly distributed, so that after the polypropylene insulation tape is melted, it flows evenly and is evenly distributed, ensuring that the polypropylene insulation tape is welded to the cable insulation layer, insulation shielding layer and stress cone as one, and will not damage the structure of the cable insulation layer, insulation shielding layer and stress cone, thereby ensuring the quality of heating and welding.

[0031] Preferably, the inner mold is provided with a mounting groove for mounting the heating unit, and a heat insulating member is provided between two adjacent heating units, and the depth of the inner side surface of the heat insulating member extending inward is greater than the depth of the inner side surface of the mounting groove extending inward; the mounting groove is provided with a heat conductive member, and the heat conductive member is located on the inner side of the heating unit. In the above structure, when the shuttle-shaped polypropylene insulating tape is heated, the heating unit generates heat, and the heat is transferred to the inner mold through the heat conductive member, and then transferred to the polypropylene insulating tape through the inner mold, so that the polypropylene insulating tape melts; in order to ensure that heat is transferred radially inward, a heat insulating member is provided to block the axial transfer of heat between the heating units, and ensure that the heat between the heating units does not affect each other, and the depth of the inner side surface of the heat insulating member extending inward is greater than the depth of the inner side surface of the mounting groove extending inward, which effectively blocks the axial transfer of heat on the inner mold, and ensures that the heat can be better transferred to the polypropylene insulating tape, thereby improving the melting effect and precision.

[0032] A polypropylene cable terminal is manufactured by a method for manufacturing a 35kV and below polypropylene cable terminal.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. A method for making a 35kV or lower polypropylene cable terminal in the present invention uses a polypropylene insulating tape material that is consistent with the cable insulation layer material, and fuses the cable insulation layer, insulation shielding layer, stress cone and the polypropylene insulating tape into one by heating, thereby removing the slippery surface between the stress cone in the cable accessory and the cable end. The polypropylene insulating tape fuses the stress cone with the cable insulation layer and insulation shielding layer well without destroying the original cable structure, avoiding the phenomenon of creepage marks at the outer semi-conductor cut of the cable, and solving the problem of discharge caused by air gaps on the slippery surface due to decreased adhesion and the problem of discharge caused by air gaps on the slippery surface due to decreased adhesion.

[0035] 2. A method for manufacturing a 35kV and below polypropylene cable terminal in the present invention has a long service life because the material of the polypropylene insulating tape is consistent with the material of the cable insulation layer in the cable end, both of which are polypropylene. Compared with thermosetting materials and rubber materials such as cross-linked polyethylene, it can be repeatedly heated and used, and its service life is consistent with the cable itself; it can effectively reduce the subsequent maintenance cost.

[0036] 3. In the method for manufacturing a 35kV and below polypropylene cable terminal of the present invention, the material of the polypropylene insulating tape is consistent with the material of the cable insulation layer in the cable end, and the insulating shielding layer is the same as the stress cone material, both containing polypropylene, so that the compatibility between the cable end and the polypropylene insulating tape is improved, and the compatible surface between the two is closely connected without a gap, avoiding discharge at the compatible surface when the cable is running. Compared with traditional cold-shrink prefabricated rubber accessories, its quality and operation safety are higher.

[0037] 4. A method for manufacturing a 35kV and below polypropylene cable terminal in the present invention, wherein the multi-umbrella-shaped rubber sleeve is an enhanced insulation structure with large and small umbrellas arranged alternately, and has no stress cone. It has good holding force and can be completely attached to the insulation surface of the restored fusion-type terminal, thereby improving the insulation performance of the fusion-type terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the structure after the cable end in the present invention is stripped.

[0039] Figure 2 It is a schematic diagram of the structure of the cable end after heating and welding treatment in the present invention.

[0040] Figure 3 It is a schematic diagram of the structure of the polypropylene cable terminal in the present invention.

[0041] Figure 4 It is a schematic diagram of the three-dimensional structure of the heating mold in the present invention when in use.

[0042] Figure 5 It is a schematic diagram of the three-dimensional structure of the heating mold in the present invention which hides the upper heating module or the lower heating module when in use.

[0043] Figure 6 It is a cross-sectional view of the heating mold in the present invention.

[0044] Figure 7 for Figure 6 A partial enlarged view of point A in the middle.

[0045] Figure 8 It is a schematic diagram of the structure of the heating unit and the heat conducting member in the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0047] Example 1

[0048] See also Figure 1-Figure 3This embodiment discloses a method for manufacturing a 35 kV and below polypropylene cable terminal 1, comprising the following steps:

[0049] (1) Cable stripping pretreatment:

[0050] The cable end is stripped to expose the cable conductor 11 and the cable insulation layer 12 at the cable end. The cable insulation layer 12 is made of polypropylene. Specifically:

[0051] Each layer of the cable end structure is stripped according to the process size, and the outer layer structure of the cable end is stripped to expose the insulating shielding layer 13; the insulating shielding layer 13 and the cable insulating layer 12 are stripped in turn according to the process size to expose the cable conductor 11 and the cable insulating layer 12; the cuts of the insulating shielding layer 13 and the cable insulating layer 12 are chamfered with a tool, and polished to make the cuts of the insulating shielding layer 13 and the cable insulating layer 12 rounded without steps, or the cuts of the insulating shielding layer 13 are only chamfered with a tool, and polished to make the cuts of the insulating shielding layer 13 rounded without steps; the cuts are cleaned; the outer layer structure includes a cable outer sheath and a metal sheath, and the metal sheath is located inside the cable outer sheath.

[0052] (2) Cable and stress cone 14 winding process:

[0053] (2.1) Wrap the polypropylene insulating tape back and forth 2-3 times from the cutout of the insulating shielding layer 13 toward the cable conductor 11 in a semi-covering manner, so that the polypropylene insulating tape covers the cutout of the insulating shielding layer 13 and the cable insulating layer 12 near the cutout;

[0054] (2.2) The stress cone 14 is placed on the outside of the insulating shielding layer 13 and the polypropylene insulating tape;

[0055] (2.3) Then, in a semi-covering manner, the polypropylene insulating tape is wound back and forth from the insulating shielding layer 13 toward the cable conductor 11 on the outside of the stress cone 14 until it becomes a shuttle shape, i.e., an olive shape; thereby, the polypropylene insulating tape is covered on the insulating shielding layer 13, the stress cone 14 and the cable insulating layer 12.

[0056] (3) Installation of auxiliary heating materials at the cable end:

[0057] A heating auxiliary material is installed on the outside of the polypropylene insulating tape that forms a shuttle-shaped structure after winding, and a temperature sensor is installed on the heating auxiliary material; by setting the heating auxiliary material, the polypropylene insulating tape can be protected when heated, and the temperature sensor is used to detect the heating temperature of the cable end and monitor the heating temperature in real time.

[0058] (4) Heating and welding treatment of cable ends:

[0059] The shuttle-shaped polypropylene insulating tape is heated and kept warm using a temperature control device, and the cable insulating layer 12, insulating shielding layer 13, and stress cone 14 are welded together with the polypropylene insulating tape; after the polypropylene insulating tape melts, a restored insulating layer 15 is formed.

[0060] (5) Removal of heating auxiliary materials at the cable end:

[0061] After the heat preservation ends, wait for the cable end to cool to room temperature, remove the heating auxiliary materials, and expose the restored insulating layer 15.

[0062] (6) Shape treatment of the cable end:

[0063] The surface of the restored insulating layer 15 is polished in shape so that the restored insulating layer 15 and the cable insulating layer 12 and insulating shielding layer 13 are evenly transitioned, and the dust on the surface of the restored insulating layer 15 is cleaned to keep the surface of the restored insulating layer 15 clean.

[0064] (7) Installation of the multi-umbrella rubber sleeve 16 and the cable terminal 17:

[0065] Install the multi-umbrella rubber sleeve 16 according to the process dimensions, and the multi-umbrella rubber sleeve 16 covers the outside of the insulating shielding layer 13, restored insulating layer 15, and cable insulating layer 12; install the cable terminal 17 at the end of the cable conductor 11; complete the production of the polypropylene cable terminal 1.

[0066] See Figure 1-Figure 3 , in step (1), use 600-mesh sandpaper to polish the cut of the insulating shielding layer 13 and the cable insulating layer 12.

[0067] See Figure 1-Figure 3 , in step (2), the shape of the stress cone 14 is "r"-shaped, which can also be called trumpet-shaped. The stress cone 14 includes a straight segment and a curved arc segment, that is, the axial cross-sectional shape of the stress cone 14 is a straight line at one end and a curved arc along the outside at the other end; the straight segment of the stress cone 14 covers the outside of the insulating shielding layer 13 and the polypropylene insulating tape, and the curved arc segment of the stress cone 14 faces the cable conductor 11; the arc port (the port of the curved arc segment) of the stress cone 14 is the midpoint of the shuttle shape. The stress cone 14 can equalize the electric field concentrated at the cut and avoid cable operation failures caused by electric field concentration.

[0068] See Figure 1-Figure 3, the material of the insulating shielding layer 13 contains polypropylene, in step (2), the stress cone 14 is pre-made in the factory, by extruding the insulating shielding layer 13 material through an extruder, heating and diverting; squeezing the insulating shielding layer 13 material into the stress cone forming mold, and controlling the temperature of the stress cone 14 by controlling the forming temperature, and after cooling, taking out the stress cone 14 from the stress cone forming mold. The purpose is that the stress cone 14 is made of the insulating shielding layer 13 material, that is, the material of the insulating shielding layer 13 is the same as the material of the stress cone 14, both containing polypropylene, and during the heating and welding process, since the material of the polypropylene insulating tape is polypropylene, the polypropylene insulating tape can be connected to the surface of the stress cone 14 and the surface of the insulating shielding layer 13 after melting to form a whole, thereby preventing the existence of a slip surface between the stress cone 14 and the insulating shielding layer 13 and the cable insulating layer 12, and will not damage the original cable structure.

[0069] See also Figure 1-Figure 3 In step (3), the heating auxiliary materials include rubber soft film, tin foil, polyimide tape, silicone rubber heating tape and thermal insulation cloth; when installing the heating auxiliary materials, rubber soft film, tin foil, polyimide tape, silicone rubber heating tape and thermal insulation cloth are sequentially installed on the outside of the polypropylene insulating tape that forms a shuttle structure after winding, and a temperature sensor is installed on the silicone rubber heating tape. In step (5), after the insulation is completed, wait for the cable end to cool to room temperature, and remove the thermal insulation cloth, silicone rubber heating tape, polyimide tape, tin foil, rubber soft film and other heating auxiliary materials in turn to expose the restored insulation layer 15.

[0070] See also Figure 1-Figure 3 In step (6), the specific steps of polishing the surface of the restored insulating layer 15 are as follows: use 240-mesh sandpaper to polish the surface of the restored insulating layer 15, so that the restored insulating layer 15 has a uniform transition with the cable insulating layer 12 and the insulating shielding layer 13, that is, one end of the restored insulating layer 15 has a uniform transition with the cable insulating layer 12, and the other end of the restored insulating layer 15 has a uniform transition with the insulating shielding layer 13; and the overall shape of the restored insulating layer 15 is shuttle-shaped, and then use 600-mesh sandpaper to polish the surface of the restored insulating layer 15, remove the traces of the 240-mesh sandpaper and polish it to a smooth finish.

[0071] See also Figure 1-Figure 3 In step (7), the specific steps of installing the cable terminal 17 on the end of the cable conductor 11 are: inserting the cable terminal 17 onto the cable conductor 11, selecting a suitable crimping mold for crimping, and finally restoring the remaining structure of the cable.

[0072] See also Figure 1-Figure 3In step (7), the multi-umbrella-shaped rubber sleeve 16 is an enhanced insulation structure with large and small umbrellas arranged alternately, and the stress-free cone 14 has a good clamping force and can be completely attached to the insulation surface of the restored fusion-type terminal, thereby improving the insulation performance of the fusion-type terminal.

[0073] Example 2

[0074] See also Figure 4-Figure 8; The other steps of the manufacturing method in this embodiment are the same as those in Embodiment 1, except that this embodiment does not require the steps of installing the cable end heating auxiliary material and removing the cable end heating auxiliary material. In the cable end heating and welding treatment step (4), a heating mold is used to heat and insulate the shuttle-shaped polypropylene insulating tape; the heating mold includes an upper heating module 2 and a lower heating module 3; the upper heating module 2 and the lower heating module 3 both include an inner mold 4 and an outer mold 5, a mold cavity 6 is provided between the two inner molds 4, the mold cavity 6 cooperates with the shuttle-shaped polypropylene insulating tape, and the outer film is arranged on the outer side of the inner mold 4; a plurality of heating units 7 are provided on the inner mold 4, and the plurality of heating units 7 are arranged along the outer contour of the shuttle-shaped polypropylene insulating tape; each heating unit 7 independently controls its heating temperature.In the above structure, the upper heating module 2 and the lower heating module 3 are connected by bolts. When in use, the upper heating module 2 and the lower heating module 3 are covered on the outside of the polypropylene insulating tape of the shuttle structure, and then the upper heating module 2 and the lower heating module 3 are fixed by bolts. Specifically, the two ends of the upper heating module 2 and the lower heating module 3 are fixed by clamps, and the clamps are fixed to the ends of the cables by bolts. The polypropylene insulating tape of the shuttle structure is located in the mold cavity 6 between the two inner molds 4, and then the heating unit 7 is heated to realize the melting of the polypropylene insulating tape; after the polypropylene insulating tape is melted, a recovery insulating layer 1 is formed. 5; the outer mold 5 has a heat-insulating effect to ensure that heat will not be lost; multiple heating units 7 are arranged along the outer contour of the shuttle-shaped polypropylene insulating tape, that is, multiple heating units 7 are arranged in a shuttle shape along the axial direction of the inner mold 4, and each heating unit 7 is at the same distance from the outer surface of the shuttle-shaped polypropylene insulating tape. Since the polypropylene insulating tape is shuttle-shaped, the heating units 7 are also arranged in a shuttle shape; since the polypropylene insulating tape is a shuttle-shaped structure, and the stress cone 14 is in the shape of a "child", the radial thickness of the polypropylene insulating tape is different. If the temperature control heating device in the prior art is used The equipment is heated, resulting in uneven heating of various areas of the polypropylene insulating tape, so that after the polypropylene insulating tape is melted, the flow is disordered and unevenly distributed, and the connection with the cable insulation layer 12, the insulation shielding layer 13, and the stress cone 14 is not uniform, and the blending is uneven, which may cause the thicker part to not be completely melted, and the thinner part transfers heat to the cable insulation layer 12 or the insulation shielding layer 13 or the stress cone 14 for a long time, resulting in the complete destruction of the structure of the cable insulation layer 12, the insulation shielding layer 13, and the stress cone 14, affecting the quality of the heating welding, and then affecting the quality of the polypropylene cable terminal; in the above structure, By setting a plurality of heating units 7, each heating unit 7 can be independently controlled. The heating unit 7 corresponding to the polypropylene insulating tape with a smaller thickness reduces the heating temperature, and the heating unit 7 corresponding to the polypropylene insulating tape with a larger thickness increases the heating temperature, so that the heat in each area of ​​the polypropylene insulating tape is evenly distributed, and the polypropylene insulating tape flows and distributes evenly after melting, thereby ensuring that the polypropylene insulating tape is fused into one with the cable insulating layer 12, the insulating shielding layer 13, and the stress cone 14, and will not damage the structure of the cable insulating layer 12, the insulating shielding layer 13, and the stress cone 14, thereby ensuring the quality of the heating fusion.

[0075] See also Figure 4-Figure 8The inner mold 4 is provided with a mounting groove 41 for mounting the heating unit 7, and a heat insulating member 8 is provided between two adjacent heating units 7. The depth of the inner side surface of the heat insulating member 8 (the side close to the axis of the inner mold 4) extending inward is greater than the depth of the inner side surface of the mounting groove 41 extending inward, that is, the heat insulating member 8 is closer to the axis of the inner mold 4 than the mounting groove 41; the mounting groove 41 is provided with a heat conducting member 9, and the heat conducting member 9 is located on the inner side of the heating unit 7. In the above structure, when the shuttle-shaped polypropylene insulating tape is heated, the heating unit 7 generates heat, transfers the heat to the inner mold 4 through the heat conductor 9, and then transfers the heat to the polypropylene insulating tape through the inner mold 4, thereby melting the polypropylene insulating tape; in order to ensure that the heat is transferred radially inward, the heat insulation member 8 is provided to block the axial transfer of heat, thereby ensuring that the heat between the heating units 7 does not affect each other, and the depth of the inner side surface of the heat insulation member 8 extending inward is greater than the depth of the inner side surface of the mounting groove 41 extending inward, thereby effectively blocking the axial transfer of heat on the inner mold 4, thereby ensuring that the heat can be better transferred to the polypropylene insulating tape, thereby improving the melting effect and accuracy.

[0076] The heat conducting member 9 and the heating unit 7 are in a semi-ring shape. The temperature of the heating unit 7 can be controlled by voltage, and each heating unit 7 controls the voltage individually, thereby achieving individual control of heat.

[0077] Example 3

[0078] See also Figure 1-Figure 3 This embodiment discloses a polypropylene cable terminal 1, which is manufactured by a 35 kV and below polypropylene cable terminal manufacturing method as described in Example 1 or Example 2.

[0079] See also Figure 1-Figure 3 The polypropylene cable terminal 1 includes a cable end and cable accessories; the cable end is a connecting end of the cable; it is a part of the cable; it includes a cable conductor 11, a cable insulation layer 12 and an insulation shielding layer 13; the cable insulation layer 12 is arranged on the outside of the cable conductor 11, and the insulation shielding layer 13 is arranged on the outside of the cable insulation layer 12. The cable end also includes an outer layer structure.

[0080] See also Figure 1-Figure 3 The cable accessories include a stress cone 14, a recovery insulation layer 15, a multi-umbrella-shaped rubber sleeve 16 and a cable terminal 17; the cable terminal 17 is installed at the end of the cable conductor 11; the recovery insulation layer 15 is formed by melting the polypropylene insulation tape, and the cable insulation layer 12, the insulation shielding layer 13, the stress cone 14 and the recovery insulation layer 15 are heated and fused into one; the multi-umbrella-shaped rubber sleeve 16 covers the insulation shielding layer 13, the recovery insulation layer 15 and the cable insulation layer 12.

[0081] See also Figure 1-Figure 3In this embodiment, the insulating shielding layer 13 and the stress cone 14 are made of the same material, which includes polypropylene; the polypropylene insulating tape and the cable insulating layer 12 are both made of polypropylene. The material of the polypropylene insulating tape used is the same as the material of the cable itself, so that the compatibility between the cable insulating layer 12, the insulating shielding layer 13, the stress cone 14 and the recovery insulating layer 15 is improved, so that the compatible surfaces between the two are closely connected without gaps, avoiding discharge at the compatible surface when the cable is running, and having higher quality and operation safety than the traditional cold shrink prefabricated rubber accessories.

[0082] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for manufacturing a 35kV and below polypropylene cable terminal, characterized in that: It includes the following steps: (1) Cable stripping pretreatment: Perform a stripping operation on the cable end to expose the cable conductor and the cable insulation layer at the cable end. The material of the cable insulation layer is polypropylene; (2) Cable and stress cone winding treatment: (2.1) Wind the polypropylene insulating tape back and forth multiple times from the cut of the insulation shield layer towards the cable conductor; (2.2) Sheath the stress cone on the outside of the insulation shield layer and the polypropylene insulating tape; (2.3) Then wind the polypropylene insulating tape back and forth from the insulation shield layer towards the cable conductor on the outside of the stress cone until it forms a spindle shape; (3) Cable end heating and fusion welding treatment: Heat and keep warm the polypropylene insulating tape in the spindle structure, and fuse the cable insulation layer, the insulation shield layer, the stress cone and the polypropylene insulating tape into one body; after the polypropylene insulating tape melts, a restored insulation layer is formed; (4) Installation of multi-umbrella rubber sleeve and cable terminal: Install the multi-umbrella rubber sleeve, and the multi-umbrella rubber sleeve covers the outside of the insulation shield layer, the restored insulation layer and the cable insulation layer; install the cable terminal at the end of the cable conductor.

2. A method for manufacturing a 35kV and below polypropylene cable terminal according to claim 1, characterized in that: In step (1), the specific steps for performing the stripping operation on the cable end are: Strip the outer structure of the cable end to expose the insulation shield layer; sequentially strip a part of the insulation shield layer and the cable insulation layer to expose the cable conductor and the cable insulation layer; the outer structure includes a cable outer sheath and a metal sheath, and the metal sheath is located inside the cable outer sheath; After exposing the cable conductor and the cable insulation layer, chamfer and polish the cut of the insulation shield layer with a tool to make the cut of the insulation shield layer round and without steps, and clean the cut.

3. A method for manufacturing a 35kV and below polypropylene cable terminal according to claim 1, characterized in that: In step (2), the shape of the stress cone is "son" type, and the stress cone includes a straight section and a curved arc section; the straight section of the stress cone covers the outside of the insulation shield layer and the polypropylene insulating tape, and the curved arc section of the stress cone faces the cable conductor.

4. A method for manufacturing a 35kV and below polypropylene cable terminal according to claim 1, characterized in that: The material of the insulation shield layer contains polypropylene. In step (2), the stress cone is pre-fabricated in the factory. The insulation shield layer material is extruded, heated and branched through an extruder; the insulation shield layer material is squeezed into the stress cone forming die, and the temperature of the stress cone is controlled by controlling the forming temperature. After cooling, the stress cone is taken out from the stress cone forming die.

5. The method for manufacturing a 35kV and below polypropylene cable terminal according to claim 1, characterized in that: Between step (2) and step (3), the following steps are also included: Installation of cable end heating auxiliary materials: Install heating auxiliary materials on the outside of the polypropylene insulating tape that forms a spindle structure after winding, and install a temperature sensor on the heating auxiliary materials; Between step (3) and step (4), the following steps are also included: Removal of cable end heating auxiliary materials: After the heat preservation is completed, wait for the cable end to cool to room temperature, remove the heating auxiliary materials, and expose the restored insulation layer.

6. A method for manufacturing a 35kV and below polypropylene cable terminal according to claim 5, characterized in that: The heating auxiliary materials include a rubber soft film, tin foil, polyimide tape, a silicone rubber heating tape and a heat insulation cloth; when installing the heating auxiliary materials, install the rubber soft film, tin foil, polyimide tape, a silicone rubber heating tape and a heat insulation cloth in sequence on the outside of the polypropylene insulating tape that forms a spindle structure after winding, and install a temperature sensor on the silicone rubber heating tape.

7. A method for manufacturing a 35kV and below polypropylene cable terminal according to claim 5, characterized in that: After the cable end heating auxiliary materials are removed, the following steps are also included: Cable end appearance treatment: Grind the surface of the restored insulation layer to make a uniform transition between the restored insulation layer and the cable insulation layer and the insulating shielding layer, clean the dust on the surface of the restored insulation layer, and keep the surface of the restored insulation layer clean.

8. The method for manufacturing a 35kV and below polypropylene cable terminal according to claim 1, characterized in that: In step (3), a heating mold is used to heat and keep the shuttle-shaped polypropylene insulating tape warm; the heating mold includes an upper heating module and a lower heating module; the upper heating module and the lower heating module both include an inner mold and an outer mold, a mold cavity is provided between the two inner molds, the mold cavity cooperates with the shuttle-shaped polypropylene insulating tape, and the outer film is arranged on the outer side of the inner mold; a plurality of heating units are provided on the inner mold, and the plurality of heating units are arranged along the outer contour of the shuttle-shaped polypropylene insulating tape; each heating unit independently controls its heating temperature.

9. A method for manufacturing a 35kV and below polypropylene cable terminal according to claim 8, characterized in that: The inner mold is provided with an installation groove for installing the heating unit, and a heat insulating member is provided between two adjacent heating units. The depth of the inner side surface of the heat insulating member extending inward is greater than the depth of the inner side surface of the installation groove extending inward; the installation groove is provided with a heat conductive member, and the heat conductive member is located on the inner side of the heating unit.

10. A polypropylene cable terminal, characterized in that: The polypropylene cable terminal is manufactured by the method for manufacturing a 35 kV and below polypropylene cable terminal as described in any one of claims 1 to 9.

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