Method for forming end corona protection layer of Roebel bar

Abstract

The present invention relates to a method for forming an end corona prevention layer of a love bar. An end corona prevention tape is wrapped around a love bar, and a release film is wrapped around the outer side thereof. A first silicone pad is placed on the outer side of the release film corresponding to the vertical side of the love bar, and a hard pressure member is placed on the outer side of the first silicone pad corresponding to the straight section. Subsequently, the hard pressure member and the first silicone pad are wrapped with a first heat shrink tape. A second silicone pad is placed on the outer side of the first heat shrink tape in an area where the hard pressure member is not placed, and then wrapped with a second heat shrink tape. Subsequently, the first and second heat shrink tapes are heated to heat shrink the end corona prevention tape, thereby hardening it through pressure and heating. Accordingly, surface pressure is applied by the hard pressure member placed on the straight section, and in the area where the hard pressure member is not placed, particularly in the curved end section, shape following is achieved through the elastic deformation of the second silicone pad. Pressurization can be applied to form a uniform end corona protection layer.

Description

Technology Field

[0001] The present invention relates to a method for forming an end corona prevention layer of a lobel bar, and more specifically, to a method for forming an end corona prevention layer of a lobel bar by taping an end corona prevention tape on a part of the straight section and a part of the end section of the lobel bar when manufacturing a lobel bar, which is a type of stator winding of a generator, and then curing the end corona prevention tape by applying pressure and heating.

[0002] In particular, the present invention relates to a method for forming an end corona prevention layer of a love bar, wherein surface pressure is applied using a rigid pressure member in the overlapping area of ​​the outer corona prevention layer and the end corona prevention tape in the straight portion of the love bar, shape-following pressure is applied using an elastically deformable silicone pad in the remaining area where the rigid pressure member is not placed, particularly in the curved end portion, and the end corona prevention layer is uniformly formed by fixing and applying pressure in stages using a first heat shrink tape and a second heat shrink tape. Background Technology

[0003] Power plants are equipped with generators, which generate electricity by utilizing heat produced by nuclear fission, heat generated by burning fuels such as oil or coal, or the kinetic energy of water such as hydropower or tidal power.

[0004] A generator is a device that converts mechanical energy into electrical energy, and its basic principle is to generate electromotive force using electromagnetic induction. For example, if a coil is placed between two magnets and rotated, a change in the magnetic field occurs within the coil. At this time, an induced electromotive force is generated at both ends of the coil, causing an induced current to flow. The current generated in this way is alternating current, which changes periodically in both strength and direction.

[0005] Specifically, a generator generates electricity by using the rotational force of a turbine, which rotates due to water or steam, to rotate the generator's rotor at high speed.

[0006] The stator winding of a large generator is a winding structure formed by electrically connecting multiple stator coils or conductors installed in the slots of the generator stator, generating an induced electromotive force by linking with the magnetic flux produced by the rotating magnetic field of the rotor, and forming a conductive path through which the generated current flows. In addition, the stator winding is configured to have a predetermined electrical dielectric strength by laminating insulating materials, such as mica-based insulating tape, on the outer side of the conductors so as to withstand the rated voltage of the generator and overvoltage that may occur during operation.

[0007] FIG. 7 is a schematic diagram showing the configuration of a general generator. A stator (2) consisting of stator coils (3) is installed on the inner outer edge of an iron core, and a rotor (4) consisting of an electromagnet or magnet corresponding to the stator coils (3) is installed on a rotating shaft (5) positioned to penetrate the center of the iron core.

[0008] Accordingly, as the rotating shaft (5) rotates, the rotor (4) installed on the rotating shaft (5) rotates at high speed, and the magnetic flux generated from the rotor (4) links with the outer stator coil (3), and current flows through the stator coil (3) due to the electromagnetic force generated at this time, thereby generating electricity.

[0009] Among these, the stator (2) is configured to prevent damage, such as breakage of the coil due to electric discharge, by providing an insulating material outside the stator coil (3), which is composed of a plurality of coils. The insulating material includes a thermosetting resin, mica, etc., and a corona prevention tape, etc., is wound on the outer side of the insulating material to prevent discharge.

[0010] When classifying the stator windings of a generator, they are divided into amorphous windings (random-wound, random winding) for low voltage of 1 MW or less and formed windings (form-wound, or formed winding) for high voltage of over 1 MW, and formed windings are further divided into diamond shape for less than 50 MW and Roebel Bar for over 50 MW.

[0011] The Roebel bar, which is the subject of the present invention, is a stator winding developed by Ludwig Roebel of Germany, in which multiple insulated conductor strands are stacked to form a stack, and in order to prevent unwanted heat generation problems caused by unnecessary circulating current flowing due to the difference in induced electromotive force between each conductor strand, the position of each conductor strand is transposed and arranged so as to periodically change along the length direction of the bar.

[0013] The manufacturing process of Robelva is largely carried out in the following order.

[0014] (1) Robelva pre-assembly manufacturing stage

[0015] A Lovelbar preassembly is manufactured comprising a plurality of stacks in which a plurality of conductor wires arranged in a potential are stacked, an insulating strip member interposed between the plurality of stacks, and an internal corona prevention member disposed at each of the potential portions at the top and bottom of the stacks.

[0016] (2) Primary pressurization and heating step

[0017] An integrated Robelbar molded body is manufactured by pressurizing and heating a Robelbar pre-assembly, wherein a plurality of stacks are joined together by the insulating strip member and the internal corona prevention member fills the empty space of the dislocation part.

[0018] That is, the insulating strip member (Separator) plays the role of maintaining the shape of the Robelbar after cooling, as the resin is squeezed out by pressurized heating and the stacks are joined together.

[0019] In addition, the Inner Corona Protection (ICP) material (such as Black mastic) spreads out through pressurized heating and fills the empty spaces in the dislocation area.

[0020] The integrated Robelbar molded body produced by the first pressurization and heating step in this way is in a straight shape.

[0021] (3) End forming step

[0022] The ends of the straight-shaped integrated love bar molded body are bent and formed so that the love bar has a shape consisting of a straight section extending in a straight line and end sections extending by bending at both ends in the longitudinal direction of the straight section.

[0023] (4) Main insulation tape and OCP taping step

[0024] After the end forming step, the main insulation tape and outer corona protection (OCP) tape are wrapped around the lobule.

[0025] The main insulation tape is applied to the entire Robelbar excluding the connection part, and after the main insulation tape is applied, the outer corona protection tape is applied to the straight part of the Robelbar.

[0026] (5) Secondary pressurization and heating step

[0027] A main insulating layer is formed by applying pressure and heating to a Robelbar wrapped with a main insulating tape and an outer corona prevention tape, while the resin of the main insulating tape is squeezed out to fill the empty space and simultaneously the insulating materials are adhered to the Robelbar.

[0028] The final dimensions and shape of the Robelbar are determined by the second pressurization and heating step.

[0029] FIG. 8 is a perspective view of a Robelba (10) manufactured by a second pressurization and heating step.

[0030] (6) ECP formation stage

[0031] End Corona Protection (ECP) tape is wrapped around the end of the Robelbar, which has undergone a second pressurization and heating step, and then heat-treated to form an end corona protection layer.

[0033] The present invention relates to an ECP formation step.

[0034] A description of the Robelva that has undergone the secondary pressurization and heating stage immediately prior to the ECP formation stage is provided.

[0035] The Lobelbar has a structure in which multiple conductor wires are stacked in a predetermined arrangement and shifted to change positions along the longitudinal direction, and can be formed in the shape of a bar having an overall rectangular cross-sectional structure.

[0036] The Robelba may include a straight section extending in a straight line along the longitudinal direction and an end section extending in a curved manner from both ends of the straight section in the longitudinal direction.

[0037] More specifically, the shape of the Robelva is described with reference to Fig. 8.

[0038] The Robelba (10) includes a straight section (11) positioned in the center and an end section (12) that is bent and extended from both ends of the straight section (11) in the longitudinal direction.

[0039] The straight section (11) is a rectangular cross-sectional structure having a vertical side extending in the vertical direction and a horizontal side extending in the horizontal direction, which is a structure that extends in a straight line along the horizontal length direction.

[0040] The end portion (12) is a structure in which a first curved portion (12a), an arc-shaped extension portion (12b), a second curved portion (12c), and an end extension portion (12d) are sequentially formed at both ends in the longitudinal direction of the straight portion (11).

[0041] The first curved section (12a) is shaped to be bent with respect to the vertical side at both ends of the longitudinal direction of the straight section (11).

[0042] The arc-shaped extension (12b) is an arc-shaped extension that extends from the first bend (12a) while bending along the horizontal side.

[0043] The second bend (12c) is shaped to be bent with respect to the vertical side at the end of the arc-shaped extension (12b).

[0044] The end extension (12d) is a shape that extends from the second bend (12c).

[0045] At the end of the terminal extension part (12d), a connection part (12d-1) is formed in which a conductor wire is exposed to the outside and can be connected, that is, a connection part (12d-1) that does not have a main insulation layer is formed.

[0046] A main insulation layer may be formed on the outer side of the love bar (10) to prevent insulation breakdown due to high voltage, and an outer corona protection layer (OCP) may be formed on the straight part where the love bar is inserted into the slot of the stator to surround the outer side of the main insulation layer.

[0047] In this way, a main insulation layer and an external corona protection layer are formed on the outer side of the Robelbar during the second pressurization and heating step.

[0048] For the Robelbar that has undergone the second pressurization and heating step, in the ECP formation step, an End Corona Protection (ECP) layer is formed from the part where the outer corona protection layer ends toward the end of the Robelbar to alleviate electric field concentration and suppress corona discharge.

[0049] The end corona prevention layer is formed by wrapping a tape having an end corona prevention function around the outer side of the lobule bar within a predetermined range, and then curing it by applying pressure and heating.

[0050] Conventionally, a method has been used in which an end corona prevention tape is wrapped around a lobel bar, a release film is wrapped around the outside thereof, silicone pads are placed on parts corresponding to the vertical sides on opposite sides of the lobel bar, and the silicone pads are wrapped with heat shrink tape.

[0051] Subsequently, when the area taped with the end corona prevention tape is inserted into a heating box and heated, the heat shrink tape shrinks and presses the silicone pad toward the lobule, and accordingly, the end corona prevention tape hardens as it is pressed and heated, thereby forming an end corona prevention layer.

[0052] However, in these conventional methods, since the shrinkage force generated by the heat-shrink tape is transmitted to the end corona prevention tape through an elastic silicone pad, a problem arises in that it is difficult to form sufficient and uniform surface pressure.

[0053] In addition, unlike the straight section, the end section of the love bar includes at least one curved section and a section extending in an arc shape, so the direction and curvature of the outer surface change depending on the position.

[0054] Therefore, when the same pressure structure is applied to the entire straight section and the curved end section, sufficient surface pressure may not be applied in the straight section, or conversely, in the curved end section, the pressure member may not sufficiently follow the curved shape of the lobel bar, resulting in a difference in local pressure.

[0055] Such uneven pressure can cause wrinkles, lifting, localized protrusions, and thickness variations in the end corona protection tape.

[0056] In addition, if sufficient pressure is not applied in the area where the outer corona protection layer and the end corona protection tape overlap, there is a problem in that the risk of partial discharge increases due to the occurrence of a step difference between that overlapping area and other parts.

[0057] Therefore, a technology is required that can uniformly press and cure the end corona prevention tape while providing appropriate pressure in response to the different shape characteristics of the overlapping area of ​​the outer corona prevention layer formed on the straight part of the love bar and the end corona prevention tape and the curved end part of the love bar. Prior art literature

[0058] Registered Patent No. 10-2268609 "Equipment for manufacturing an integrated high-compression stator coil for a high-voltage generator" (Registered June 17, 2021) Registered Patent No. 10-2268610 "Method for manufacturing an integrated high-compression stator coil for a high-voltage generator" (Registered June 17, 2021) The problem to be solved

[0059] The present invention was devised to solve the problems of the prior art as described above, and aims to provide a method for forming an end corona prevention layer of a lobel bar that can uniformly press the end corona prevention tape while providing appropriate pressure in response to the different shape characteristics of the overlapping area of ​​the outer corona prevention layer formed on the straight part of the lobel bar and the end corona prevention tape and the curved end part of the lobel bar.

[0060] Another objective of the present invention is to provide a method for forming an end corona prevention layer of a love bar, wherein a rigid pressure member is used to provide uniform surface pressure to the end corona prevention tape in the overlapping area between the outer corona prevention layer formed on the straight portion of the love bar and the end corona prevention tape, and an elastically deformable silicone pad is used to apply pressure to the end corona prevention tape along the curved shape of the end portion in the curved end portion.

[0061] Another objective of the present invention is to provide a method for forming an end corona prevention layer of a love bar that can stably position pressure members and provide different pressure characteristics depending on a specific location in the love bar by first fixing a first silicone pad and a hard pressure member with a first heat shrink tape to form a first pressure structure, and then adding a second silicone pad in an area where the hard pressure member is not placed and fixing it with a second heat shrink tape to form a second pressure structure.

[0062] Another objective of the present invention is to reduce wrinkles, lifting, voids, localized protrusions, and thickness variations that may occur during the curing process of the end corona prevention tape, and to suppress the occurrence of step differences in the overlapping area between the outer corona prevention layer and the end corona prevention tape compared to other parts. means of solving the problem

[0063] To solve the above problem, the present invention provides a method for forming an end corona prevention layer of a love bar, wherein the love bar comprises a rectangular cross-sectional structure having a pair of vertical sides and a pair of horizontal sides, a straight section extending straight along the longitudinal direction, and end sections extending by bending at both ends of the longitudinal direction of the straight section, wherein the end sections include a first bending section bent with respect to the vertical sides at both ends of the longitudinal direction of the straight section and an arc-shaped extension section extending in an arc shape from the first bending section, the method comprising: a love bar preparation step of preparing a love bar in which a main insulating layer is formed over the entire longitudinal direction excluding a connection section, and an external corona prevention layer is formed to surround the main insulating layer in the straight section; and an end corona prevention taping step of wrapping an end corona prevention tape so as to continuously wrap the end of the straight section of the prepared love bar and a part of the first bending section and the arc-shaped extension section, wherein a part of the end corona prevention tape wrapped at the end of the straight section wraps a part of the end of the external corona prevention layer and forms an overlapping area with the external corona prevention layer. A release film placement step of wrapping the outer side of the end corona prevention tape with a release film; a first silicone pad placement step of placing a first silicone pad on the outer side of the release film corresponding to opposite vertical sides of the love bar; a hard pressure member placement step of placing a hard pressure member on each outer side of the first silicone pad corresponding to the straight section, wherein the hard pressure member is placed over an area including the entire overlapping area of ​​the end corona prevention tape and the outer corona prevention layer and a part of the end corona prevention tape that does not wrap the outer corona prevention layer; a first heat shrink taping step of wrapping the hard pressure member with a first heat shrink tape and also wrapping the first silicone pad in the area where the hard pressure member is not placed;A second silicone pad placement step of placing a second silicone pad on the outer side of the first heat shrink tape corresponding to opposite vertical sides of the love bar in an area of ​​the entire area of ​​the first heat shrink tape where the rigid pressure member is not placed; a second heat shrink taping step of wrapping the portion of the first heat shrink tape wrapped around the rigid pressure member and the second silicone pad with the second heat shrink tape; a heating step of inserting the portion wrapped around the end corona prevention tape into a heating box and heating it after the second heat shrink taping, so that the first heat shrink tape and the second heat shrink tape are heat-shrinked, and the end corona prevention tape is hardened while being pressurized and heated to form an end corona prevention layer; and a removal step of removing the release film and the components placed on the outer side of the release film after the heating step; characterized by comprising.

[0064] In the above, the cross-sectional shape of the rigid pressure member is symmetrical and has a shape in which the width gradually decreases as it moves outward from the first silicone pad, and the second silicone pad preferably comprises a second-1 silicone pad disposed in the center of the outer width direction of the first heat shrink tape and having a width narrower than the width of the first silicone pad, and a second-2 silicone pad disposed in the center of the outer width direction of the second-1 silicone pad and having a width narrower than the width of the second-1 silicone pad. Effects of the invention

[0065] As described above, the present invention can provide uniform surface pressure to the end corona prevention tape by placing a rigid pressure member in the overlapping area of ​​the outer corona prevention layer formed on the straight part of the lobel bar and the end corona prevention tape, thereby transmitting the shrinkage force of the heat shrink tape to a wide area on the flat vertical side of the lobel bar.

[0066] In addition, by placing a second silicone pad capable of elastic deformation in the curved end portion, etc., where a rigid pressure member is not placed, the second silicone pad can deform in response to the change in curvature of the first curved portion and the arc-shaped extension portion, thereby applying pressure to the end corona prevention tape.

[0067] Accordingly, the present invention can provide different pressure characteristics suitable for each of the flat straight section and the curved end section formed in a single lobel bar.

[0068] In addition, the present invention forms a first pressure structure by first wrapping a first silicone pad and a hard pressure member with a first heat shrink tape, and then additionally places a second silicone pad on the outside of the first heat shrink tape and wraps it with a second heat shrink tape, so that the hard pressure member and the second silicone pad can be stably maintained at different positions.

[0069] In addition, the present invention forms a stepwise pressure structure in which a second silicone pad is interposed between a first heat shrink tape and a second heat shrink tape, thereby enabling the formation of different pressure transmission paths in the straight section and the end section, unlike simply winding the heat shrink tape twice.

[0070] In addition, since the end corona prevention tape can be cured under a uniformly pressed state, the occurrence of wrinkles, lifting, localized protrusions, and voids that may occur in the end corona prevention layer can be suppressed, and the overlapping area of ​​the outer corona prevention layer and the end corona prevention tape can prevent step differences from occurring in other parts, thereby having the effect of reducing partial discharge.

[0071] Accordingly, the present invention can contribute to maintaining the quality of the end corona prevention layer uniformly and improving the reliability of the corona prevention performance. Brief explanation of the drawing

[0072] FIG. 1 is an enlarged cross-sectional view of the main part of a lobel bar, which is the target for forming an end corona prevention layer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of FIG. 1 in which an end corona prevention tape, a release film, a first silicone pad, a rigid pressure member, and a first heat shrink tape are provided. FIG. 3 is a cross-sectional view of FIG. 2 in which a second silicone pad and a second heat shrink tape are provided. FIG. 4 is a cross-sectional view based on AA of FIG. 3, FIG. 5 is a cross-sectional view based on BB of FIG. 3, FIG. 6 is a photograph of a lobel bar having an end corona prevention layer formed according to an embodiment of the present invention, FIG. 7 is a schematic diagram showing the configuration of a typical generator, FIG. 8 is a perspective view of a typical Lobelbar manufactured by a secondary pressurization and heating step. Specific details for implementing the invention

[0073] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0074] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0076] Hereinafter, a method for forming an end corona prevention layer of a lobel bar according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0077] A method for forming an end corona prevention layer of a love bar according to an embodiment of the present invention comprises: 1. a love bar preparation step -> 2. an end corona prevention taping step -> 3. a release film placement step -> 4. a first silicone pad placement step -> 5. a rigid pressure member placement step -> 6. a first heat shrink taping step -> 7. a second silicone pad placement step -> 8. a second heat shrink taping step -> 9. a heating step -> 10. a removal step.

[0079] 1. Robelva Preparation Phase

[0080] First, prepare a Robelba (10) as shown in Fig. 8.

[0081] The Robelbar (10) in Fig. 8 is a Robelbar that has undergone a secondary pressurization and heating step, and is a Robelbar that is the target for ECP formation.

[0082] The Robelbar (10) includes a plurality of conductor wires, and the plurality of conductor wires are displaced so as to change positions relative to each other along the longitudinal direction to form a bar shape overall.

[0083] The Robelbar (10) has a rectangular cross-sectional structure, and a pair of relatively long faces can be called vertical side faces, and a pair of relatively short faces can be called horizontal side faces.

[0084] As previously described, the Robelba (10) includes a straight section (11) that extends in a straight line and an end section (12) that extends by bending at both ends of the straight section (11).

[0085] The end portion (12) may include a first curved portion (12a) that is bent with respect to the vertical side at the longitudinal end of the straight portion (11), and an arc-shaped extension portion (12b) that extends in an arc shape from the first curved portion (12a).

[0086] If necessary, the end portion (12) may further include additional bends and connections extending from the arc-shaped extension portion (12b).

[0087] However, the scope of application of the method for forming an end corona prevention layer according to the present invention is not limited to a specific shape of a lobel bar as described above.

[0088] FIG. 1 is a conceptually enlarged illustration of the straight section (11), the first curved section (12a), and the arc-shaped extension section (12b) of FIG. 8.

[0089] A main insulating layer (13) is formed on the outer side excluding the connection part of the Robelbar (10).

[0090] In the above and below, the structure inside the main insulating layer (13) of the Robelbar (10) is referred to as the wire section (10a).

[0091] An external corona protection layer (14) is formed on the outer side of the main insulation layer (13) of the straight section (11).

[0093] 2. End Corona Prevention Taping Step

[0094] After Fig. 1, the end corona prevention tape (101) is wrapped around the robel bar (10) as shown in Fig. 2.

[0095] The end corona prevention tape (101) is wound to continuously wrap the end of the straight section (11), the first curved section (12a), and at least a portion of the arc-shaped extension section (12b).

[0096] In one embodiment, the end corona prevention tape (101) may start at the end of the straight section (11), pass through the first curved section (12a), and extend to the middle of the arc-shaped extension section (12b).

[0097] Additionally, a portion of the end corona prevention tape (101) wound on the end of the straight portion (11) is formed to wrap around a portion of the end of the outer corona prevention layer (14).

[0098] Accordingly, a predetermined overlapping area is formed between the outer corona prevention layer (14) and the end corona tape (101).

[0100] 3. Release film placement step

[0101] As shown in FIG. 2, when the taping of the end corona prevention tape (101) is completed, a release film (102) is wound to wrap around the outer side of the end corona prevention tape (101).

[0102] The release film (102) prevents the first silicone pad (110), etc. from being attached to the end corona prevention tape (101) in a subsequent step, and allows other components placed on the outside of the release film (102) to be easily removed.

[0103] The release film (102) may be provided to wrap the entire area or more of the end corona prevention tape (101) wound thereon.

[0105] 4. First silicone pad placement step

[0106] As shown in FIG. 2, after the release film (102) is placed, a first silicone pad (110) is placed on each of the outer sides of the release film (102) corresponding to the opposite sides of the vertical direction of the love bar (10).

[0107] The first silicone pad (110) is placed at each portion corresponding to opposite sides of the vertical direction of the love bar (10), and is not placed at the portion corresponding to opposite sides of the horizontal direction of the love bar (10).

[0108] In addition, the first silicone pad (110) is placed over the entire longitudinal area where the end corona prevention tape (101) is wound.

[0109] The first silicone pad (110) is formed of an elastic silicone material and can relieve local pressure concentration while transmitting pressure applied from the outside to the end corona prevention tape (101).

[0111] 5. Step of placing the rigid pressurizing member

[0112] A hard pressure member (130) is placed on each of the outer sides of the first silicone pad (110) corresponding to the straight section (11).

[0113] The rigid pressure member (130) has higher rigidity than the first silicone pad (110) and can be extended longitudinally along the straight section (11).

[0114] The rigid pressure member (130) is positioned over an area including the overlapping region of the outer corona protection layer (14) and the end corona protection tape (101). That is, the rigid pressure member (130) is positioned over an area including the entire region of the end corona protection tape (101) covering the outer corona protection layer (14) and a part region of the end corona protection tape (101) not covering the outer corona protection layer (14).

[0115] The cross-sectional shape of the rigid pressure member (130) is symmetrical and gradually decreases in width as it moves outward from the first silicone pad (110).

[0116] That is, as shown in FIG. 4, the cross-sectional shape of the hard pressure member (130) is a trapezoidal shape or an isosceles triangle shape in which the length of the outer upper side is very short compared to the length of the inner lower side.

[0117] The rigid pressure member (130) may be formed of wood, synthetic resin, metal, or other materials having a certain degree of rigidity, and the material is not particularly limited.

[0118] The rigid pressure member (130) is positioned to correspond to the flat vertical side surface of the straight section (11), so that the shrinkage force of the heat shrink tape can be distributed over a wide area and transmitted to the first silicone pad (110).

[0119] In particular, a rigid pressure member (130) having a trapezoidal cross-sectional structure or an isosceles triangle cross-sectional structure allows the shrinkage force of the heat shrink tape to be evenly distributed evenly to the center in the width direction of the first silicone pad (110).

[0121] 6. First heat shrink taping step

[0122] As shown in FIG. 2, after the first silicone pad (110) and the hard pressure member (130) are arranged, the first heat shrink tape (103) is wrapped around the hard pressure member (130) and the first silicone pad (110).

[0123] That is, the first heat shrink tape (103) wraps around the hard pressure member (130) placed on the outside of the first silicone pad (110) and also wraps around the first silicone pad (110) where the hard pressure member (130) is not placed.

[0124] The first heat shrink tape (103) can fix the first silicone pad (110) and the hard pressure member (130) to the love bar (10) to prevent them from moving or detaching during subsequent processes.

[0125] Accordingly, the first silicone pad (110), the hard pressure member (130), and the first heat shrink tape (103) can form a first pressure structure.

[0126] The first heat shrink tape (103) can be continuously wound to wrap around the entire area where at least the end corona prevention tape (101) is formed.

[0128] 7. Second silicone pad placement step

[0129] After FIG. 2, when the taping of the first heat shrink tape (103) is completed as in FIG. 3, a second silicone pad (120) is placed on the outside of the first heat shrink tape (103) in an area where the rigid pressure member (130) is not placed.

[0130] That is, for the first heat shrink tape (103) in the area of ​​the first heat shrink tape (103) where the hard pressure member (130) is not placed, the second silicone pad (120) is placed on each of the outer sides of the first heat shrink tape (103) corresponding to the opposite sides of the vertical direction of the love bar (10).

[0131] The second silicone pad (120) is positioned to correspond to the end portion (12), which includes the first curved portion (12a) and the arc-shaped extension portion (12b), and the second silicone pad (120) may also be positioned in a part of the straight portion (11) where the hard pressure member (130) is not positioned.

[0132] The rigid pressure member (130) placed in the overlapping area of ​​the straight section (11) has high rigidity and therefore cannot correspond to the shape of the curved end section (12), but the second silicone pad (120) is elastically deformable and can be deformed according to the curvature and change in the outer direction of the first curved section (12a) and the arc-shaped extension section (12b) and adhere to the outside of the end section (12).

[0133] In particular, the second silicone pad (120) is placed on the outside of the first heat shrink tape (103).

[0134] Therefore, since the first silicone pad (110) and the hard pressure member (130) are first fixed with the first heat shrink tape (103), the second silicone pad (120) can be additionally installed, so each pressure member (110, 120, 130) can be stably positioned at a predetermined location.

[0135] In this embodiment, the second silicone pad (120) is composed of a second-1 silicone pad (121) and a second-2 silicone pad (122).

[0136] The second-1 silicone pad (121) is positioned in the outer width direction center of the first heat shrink tape (103) and has a width narrower than the width of the first silicone pad (110).

[0137] The second-2 silicone pad (122) is positioned in the outer width direction center of the second-1 silicone pad (121) and has a width narrower than the width of the second-1 silicone pad (121).

[0138] This structure allows the second silicone pad (120) to have a cross-sectional structure similar to that of the hard pressure member (130), thereby minimizing changes in shrinkage force between the second silicone pad (120) and the hard pressure member (130), and also allows the shrinkage force of the second heat shrink tape (104) to be evenly distributed to the center of the width direction of the second silicone pad (120).

[0140] 8. Second heat shrink taping step

[0141] When the placement of the second silicone pad (120) is completed, the second heat shrink tape (104) is wrapped to cover the portion of the first heat shrink tape (103) that covers the hard pressure member (130) and the second silicone pad (120) as shown in FIG. 3.

[0142] The second heat shrink tape (104) can secure the second silicone pad (120) to the outside of the first heat shrink tape (103) and at the same time bind the entire pressure structure.

[0143] At this time, in the portion of the straight section (11) where the rigid pressure member (130) is placed, the release film (102), the first silicone pad (110), the rigid pressure member (130), the first heat shrink tape (103), and the second heat shrink tape (104) are sequentially laminated.

[0144] On the other hand, in a part of the straight section (11) and the end section (12) where the rigid pressure member (130) is not placed, a release film (102), a first silicone pad (110), a first heat shrink tape (103), a second silicone pad (120), and a second heat shrink tape (104) can be sequentially laminated.

[0145] Therefore, different pressure-layered structures can be formed on a single Lobel bar (10).

[0147] 9. Heating step

[0148] When the taping of the second heat shrink tape (104) is completed, the end portion of the Robelbar (10) wrapped with corona prevention tape (101) is inserted into a heating box and heated to a predetermined temperature.

[0149] The first heat shrink tape (103) and the second heat shrink tape (104) are each heat shrinked by heating.

[0150] In the portion of the straight section (11) where the rigid pressure member (130) is placed, the shrinkage force of the first and second row shrink tapes (103) (104) presses the rigid pressure member (130) toward the Robelbar (10).

[0151] Since the rigid pressure member (130) has high rigidity, it can transmit the contraction force over a wide area along the vertical side of the straight section (11) and uniformly apply pressure to the end corona prevention tape (101) through the first silicone pad (110), thereby minimizing the step difference between the outer corona prevention layer (14) and the end corona prevention tape (101) in the overlapping area.

[0152] On the other hand, in the area where the rigid pressure member (130) is not placed, that is, in part of the straight section (11) and part of the end section (12), the shrinkage force of the second heat shrink tape (104) presses the second silicone pad (120) toward the love bar (10), and additionally, the shrinkage force of the first heat shrink tape (103) can press the first silicone pad (110) toward the love bar (10).

[0153] The second silicone pad (120) can be elastically deformed along the shape of a part of the straight section (11), the first curved section (12a), and the arc-shaped extension section (12b), and can press the first heat shrink tape (103) and the first silicone pad (110) toward the Robelbar (10).

[0154] Therefore, at the end portion (12), the end corona prevention tape (101) can be pressed while following the curved shape of the end portion (12).

[0155] In this state, the end corona prevention tape (101) is hardened while being pressurized and heated, so that an end corona prevention layer can be formed on the outer surface that is relatively uniformly pressurized and hardened.

[0157] 10. Removal Step

[0158] When the curing of the end corona prevention tape (101) is completed by the heating step above, the Robelbar (10) is withdrawn from the heating box and the release film (102) and the components placed on the outside thereof are removed.

[0159] That is, the second heat shrink tape (104), the second silicone pad (120), the first heat shrink tape (103), the rigid pressure member (130), the first silicone pad (110), and the release film (102) are removed.

[0160] Since the release film (102) is interposed between the end corona prevention layer and the first silicone pad (110), the first silicone pad (110) and the components disposed on the outside thereof can be easily removed.

[0162] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art may implement the present invention in various forms. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0163] The scope of the present invention is defined by the claims set forth below. Explanation of the symbols

[0165] 10 : Robelva 11: Straight section 12: End section 12a: First bend 12b: Arc-shaped extension 13: Main insulation layer 14: External COVID-19 prevention layer 101: End Corona Prevention Tape 102 : Release film 103: 1st Heat Shrink Tape 104: 2nd heat shrink tape 110: First silicone pad 120 : Second silicone pad 121 : 2-1 Silicone Pad 122 : 2-2 Silicone Pad 130 : Rigid pressure member

Claims

Claim 1 A method for forming an end corona prevention layer of a love bar, wherein a rectangular cross-sectional structure having a pair of vertical sides and a pair of horizontal sides comprises a straight section extending straight along the longitudinal direction and end sections extending by bending at both ends of the longitudinal direction of the straight section, wherein the end sections comprise a first bending section bent with respect to the vertical sides at both ends of the longitudinal direction of the straight section and an arc-shaped extension section extending in an arc shape from the first bending section, the method comprising: a love bar preparation step of preparing a love bar in which a main insulation layer is formed over the entire longitudinal direction excluding a connection section and an external corona prevention layer is formed to surround the main insulation layer in the straight section; an end corona prevention taping step of wrapping an end corona prevention tape to continuously wrap the end of the straight section of the prepared love bar and a part of the first bending section and the arc-shaped extension section, wherein a part of the end corona prevention tape wrapped at the end of the straight section wraps a part of the end of the external corona prevention layer and forms an overlapping area with the external corona prevention layer; and a release film placement step of wrapping the outer side of the end corona prevention tape with a release film. A first silicone pad placement step of placing a first silicone pad on the outer side of the release film corresponding to opposite vertical sides of the love bar; a hard pressure member placement step of placing a hard pressure member on each outer side of the first silicone pad corresponding to the straight portion, wherein the hard pressure member is placed over an area including the entire overlapping area of ​​the end corona prevention tape and the outer corona prevention layer and a part of the end corona prevention tape that does not wrap the outer corona prevention layer; a first heat shrink taping step of wrapping the hard pressure member with a first heat shrink tape and also wrapping the first silicone pad in the area where the hard pressure member is not placed;A method for forming an end corona prevention layer of a love bar, comprising: a second silicone pad placement step of placing a second silicone pad on the outer side of the first heat shrink tape corresponding to opposite vertical sides of the love bar in an area of ​​the entire region of the first heat shrink tape where the rigid pressure member is not placed; a second heat shrink taping step of wrapping the portion of the first heat shrink tape wrapped around the rigid pressure member and the second silicone pad with the second heat shrink tape; a heating step of inserting the portion wrapped around the end corona prevention tape into a heating box and heating it after the second heat shrink taping, thereby heat shrinking the first heat shrink tape and the second heat shrink tape while the end corona prevention tape is pressurized and heated to harden, thereby forming an end corona prevention layer; and a removal step of removing the release film and the components placed on the outer side of the release film after the heating step. Claim 2 A method for forming an end corona prevention layer of a love bar, wherein, in claim 1, the cross-sectional shape of the rigid pressure member is symmetrical and the width gradually decreases as it moves outward from the first silicone pad, and the second silicone pad comprises a second-1 silicone pad disposed in the center of the outer width direction of the first heat shrink tape and having a width narrower than the width of the first silicone pad, and a second-2 silicone pad disposed in the center of the outer width direction of the second-1 silicone pad and having a width narrower than the width of the second-1 silicone pad.

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