Method for forming a cable intermediate connection structure and cable intermediate connection structure

Abstract

A method for forming a cable intermediate connection structure, wherein the cable intermediate connection structure connects one end of a first power cable having at least a first cable conductor, a first cable insulator, and a first outer semiconductive layer from its center outwards to one end of a second power cable having at least a second cable conductor, a second cable insulator, and a second outer semiconductive layer from its center outwards. The method comprises: a first power cable cutting step, in which a cutter is used to perform staged stripping and cutting of the first power cable with the first outer semiconductive layer exposed at one end, from one end to the other, exposing one end of the first cable conductor and one end of the first cable insulator, and forming a first cutting end with a undulation width of 6.0 mm or less and a first cutting inclined portion extending from the first cutting end to the other end with an angle greater than 5.00 degrees and less than 8.00 degrees; and a second power cable cutting step, in which the first cable conductor, a first cable insulator, and a second outer semiconductive layer are exposed at one end of the first power cable. 2. A power cable is subjected to a step-by-step stripping and cutting process using a cutter, exposing one end of the second cable conductor and one end of the second cable insulator. A second cutting end with a ripple width of 6.0 mm or less and a second cutting inclined portion extending from the second cutting end to the other end with an angle greater than 5.00 degrees and less than 8.00 degrees are formed on one end of the second outer semiconductive layer. In the connection process, a conductor connection portion is used to connect the end of the first cable conductor exposed by the first power cable cutting process and the end of the second cable conductor exposed by the second power cable cutting process. In the installation process, a cylindrical semiconductive portion is formed at least on the outer periphery of the conductor connection portion, the outer periphery of the exposed portion of the first cable conductor, and the outer periphery of the exposed portion of the second cable conductor. A cylindrical insulating unit is installed extending from the outer periphery of the exposed portion of the first outer semiconductive layer to the outer periphery of the exposed portion of the second outer semiconductive layer.

Description

Technical Field

[0001] This invention relates to a method for forming a cable intermediate connection structure and the cable intermediate connection structure itself. Background Technology

[0002] Previously, it was known that when forming a cable intermediate connection structure that connects the ends of two power cables to each other, a process was required to remove the outer semiconducting layer (hereinafter also referred to as the outer conductor) in a sloping manner from one end of the power cable to the other end.

[0003] In this process, firstly, on one end of the power cable, tools are used to manually cut away the sheath, metal shielding layer, and semi-conductive tape layer sequentially from the outside of the cable, exposing the outer conductor at one end. Next, on the end with the exposed outer conductor, for example using a glass plate, the outer conductor is manually cut towards the other end of the cable in a ramp shape, exposing both the conductor and insulation at that end. This cutting of the outer conductor relies not only on the operator's skill but also requires a considerable amount of time.

[0004] In addition, in Patent Document 1, regarding the intermediate connection structure of the cable, it is described that when the angle of the cutting end of the outer semiconductive layer is large, due to the ease of partial discharge, the cutting end of the outer semiconductive layer is made by using an external conductor cutting machine to make the angle of the cutting end of the outer semiconductive layer less than 5 degrees, and a structure is made to apply pressure from the outer periphery of the rubber block insulator.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 4283778 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in Patent Document 1, when an external semiconductive layer with the above-described shape is fabricated using an external guide cutting machine, insulation breakdown of the intermediate connection structure of the cable is sometimes not sufficiently suppressed.

[0010] The purpose of this invention is to provide a method for forming a cable intermediate connection structure that can suppress insulation breakdown, is quick and simple, and also provides the cable intermediate connection structure itself.

[0011] Methods for solving problems

[0012] [1] A method for forming a cable intermediate connection structure, wherein the cable intermediate connection structure connects one end of a first power cable to one end of a second power cable, wherein the first power cable has at least a first cable conductor, a first cable insulator and a first outer semiconductive layer from the center to the outer periphery, and the second power cable has at least a second cable conductor, a second cable insulator and a second outer semiconductive layer from the center to the outer periphery, and the method for forming the cable is characterized by having:

[0013] In the first power cable cutting process, for the first power cable with the first outer semiconductive layer exposed at one end, a cutter is used to perform a staged stripping and cutting of the first power cable from one end to the other end, exposing one end of the first cable conductor and one end of the first cable insulator, and forming a first cutting end and a first cutting inclined portion at one end of the first outer semiconductive layer. The first cutting end has a ripple width of 6.0 mm or less, and the first cutting inclined portion extends from the first cutting end to the other end and has an angle of greater than 5.00 degrees and less than 8.00 degrees.

[0014] In the second power cable cutting process, for the second power cable with the second outer semiconductive layer exposed at one end, a cutter is used to perform a staged stripping and cutting of the second power cable from one end to the other end, exposing one end of the second cable conductor and one end of the second cable insulator. A second cutting end and a second cutting inclined portion are formed at one end of the second outer semiconductive layer. The second cutting end has a ripple width of 6.0 mm or less, and the second cutting inclined portion extends from the second cutting end to the other end and has an angle of greater than 5.00 degrees and less than 8.00 degrees.

[0015] In the connection process, a conductor connection portion is used to connect the end of the first cable conductor exposed in the first power cable cutting process and the end of the second cable conductor exposed in the second power cable cutting process; and

[0016] In the installation process, a cylindrical semiconducting portion is formed at least on the outer periphery of the conductor connection portion, the outer periphery of the exposed portion of the first cable conductor, and the outer periphery of the exposed portion of the second cable conductor, and a cylindrical insulating unit is installed extending from the outer periphery of the exposed portion of the first outer semiconducting layer to the outer periphery of the exposed portion of the second outer semiconducting layer.

[0017] [2] The method for forming a cable intermediate connection structure as described in [1] above, wherein in the above installation process, after applying insulating oil across the outer peripheral surface of the exposed portion of the first outer semiconductive layer to the outer peripheral surface of the exposed portion of the second outer semiconductive layer, the above insulating unit is installed.

[0018] [3] The method for forming the intermediate connection structure of the cable as described in [2] above, wherein the insulating oil is fluorinated oil.

[0019] [4] The method for forming the cable intermediate connection structure as described in any one of [1] to [3] above, wherein the insulating unit is formed of silicone rubber.

[0020] In the above installation process, the diameter expansion retaining component is extracted from the above insulating unit and installed on the above insulating unit. The diameter expansion retaining component is formed by winding it into a spiral shape on the inner circumferential surface of the above insulating unit and expands and retains the inner circumferential surface of the above insulating unit.

[0021] [5] The method for forming a cable intermediate connection structure as described in any one of [1] to [4] above, wherein, before the above installation step, there is a removal step that removes at least one of the step difference portion on the other end of the first cutting inclined portion and the step difference portion on the other end of the second cutting inclined portion.

[0022] [6] A cable intermediate connection structure, which connects one end of a first power cable to one end of a second power cable, wherein the first power cable has at least a first cable conductor, a first cable insulator and a first outer semiconductive layer from its center to its outer periphery, and the second power cable has at least a second cable conductor, a second cable insulator and a second outer semiconductive layer from its center to its outer periphery, the cable intermediate connection structure being characterized in that it comprises:

[0023] A conductor connector that connects one end of the first cable conductor to one end of the second cable conductor; and

[0024] An insulating unit that covers the area from the outer periphery of one end of the first outer semiconducting layer to the outer periphery of one end of the second outer semiconducting layer.

[0025] Wherein, the undulation width of the first cutting end on one end side of the first outer semiconductive layer covered by the aforementioned insulating unit is 6.0 mm or less, and the standing angle of the first cutting inclined portion extending from the first cutting end to the other end side is greater than 5.00 degrees and less than 8.00 degrees.

[0026] The undulation width of the second cutting end on one end side of the second outer semiconductive layer covered by the above-mentioned insulating unit is 6.0 mm or less, and the standing angle of the second cutting inclined portion extending from the second cutting end to the other end side is greater than 5.00 degrees and less than 8.00 degrees.

[0027] Invention Effects

[0028] According to the present invention, a method for forming a cable intermediate connection structure that can suppress insulation breakdown, is quick and simple, and a cable intermediate connection structure can be provided. Attached Figure Description

[0029] [ Figure 1 ] Figure 1 This is a longitudinal sectional view illustrating an example of a cable intermediate connection structure according to an embodiment.

[0030] [ Figure 2 ] Figure 2 yes Figure 1 An enlarged cross-sectional view of the intermediate connection structure of the cable.

[0031] [ Figure 3 ] Figure 3 This is a side view showing an example of one end of the first power cable obtained by the first power cable cutting process.

[0032] [ Figure 4 ] Figure 4 yes Figure 3 An enlarged side view of one end of the first power cable.

[0033] [ Figure 5 ] Figure 5 This is a side view showing an example of one end of the second power cable obtained by the second power cable cutting process.

[0034] [ Figure 6 ] Figure 6 yes Figure 5 An enlarged side view of one end of the second power cable.

[0035] [ Figure 7 ] Figure 7 This is a side view showing an example of the connection process.

[0036] [ Figure 8 ] Figure 8 This is a cross-sectional view showing an example of the installation process for installing an insulating unit with an expanded diameter retaining member. Detailed Implementation

[0037] The following is a detailed description based on the implementation method.

[0038] The inventors of this application discovered that when an external semiconductive layer with a cutting end having an angle of less than 5 degrees is manufactured using an external conductor cutting machine, as in Patent Document 1, the end of the external conductor, which serves as the starting point of the external conductor, sometimes deviates significantly. Consequently, the smoothness of the end of the external conductor is reduced, and insulation breakdown of the cable intermediate connection structure cannot be adequately suppressed. The inventors of this application conducted further in-depth research and found that when a cutting machine is used to perform staged stripping and cutting on one end of the power cable with the external semiconductive layer exposed in order to expose the conductor and insulator, if the angle of the cutting inclination portion of the external semiconductive layer is less than 5.00 degrees, the smoothness of the cutting end of the external semiconductive layer is poor. Therefore, even if the poorly smooth cutting end is covered with an insulating unit, the semiconductive portion at the end of the insulating unit cannot completely cover the cutting end of the external semiconductive layer. The electric field concentrates at the cutting end, making insulation breakdown of the cable intermediate connection structure more likely. Furthermore, the inventors of this application, focusing on the shape of the cutting end and the cutting tilt portion of the external semiconductive layer formed using a cutting tool, discovered that by ensuring the undulation width of the cutting end and the vertical angle of the cutting tilt portion satisfy a predetermined relationship, insulation breakdown of the intermediate connection structure of the cable can be suppressed. This invention is based on this insight.

[0039] The method for forming a cable intermediate connection structure according to the embodiment is a method for forming a cable intermediate connection structure connecting one end of a first power cable having at least a first cable conductor, a first cable insulator, and a first outer semiconductive layer from the center outwards, and one end of a second power cable having at least a second cable conductor, a second cable insulator, and a second outer semiconductive layer from the center outwards. The method includes: a first power cable cutting step, wherein, for the first power cable where the first outer semiconductive layer is exposed at one end, a cutting step is performed... The device performs a staged stripping and cutting process on one end of the first power cable towards the other end, exposing one end of the first cable conductor and one end of the first cable insulation. A first cutting end with a undulating width of 6.0 mm or less and a first cutting inclined portion extending from the first cutting end towards the other end with an angle greater than 5.00 degrees and less than 8.00 degrees are formed on one end of the first outer semiconductive layer. The second power cable cutting process involves further cutting the exposed upper portion of the second outer semiconductive layer at one end. The second power cable is subjected to a step-by-step stripping and cutting process using a cutter, exposing one end of the conductor and one end of the insulation of the second cable. A second cutting end with a ripple width of 6.0 mm or less and a second cutting inclined portion extending from the second cutting end to the other end with an angle greater than 5.00 degrees and less than 8.00 degrees are formed on one end of the second outer semiconductive layer. In the connection process, a conductor connection portion is used to connect the first power cable... The process involves connecting the end of the first cable conductor exposed during the power cable cutting process with the end of the second cable conductor exposed during the second power cable cutting process; and an installation process in which a cylindrical semiconducting portion is formed at least on the outer periphery of the conductor connection portion, the outer periphery of the exposed portion of the first cable conductor, and the outer periphery of the exposed portion of the second cable conductor, and a cylindrical insulating unit is installed in the range extending from the outer periphery of the exposed portion of the first outer semiconducting layer to the outer periphery of the exposed portion of the second outer semiconducting layer.

[0040] The cable intermediate connection structure of the embodiment is a cable intermediate connection structure that connects one end of a first power cable having at least a first cable conductor, a first cable insulator, and a first outer semiconductive layer from its center outwards to one end of a second power cable having at least a second cable conductor, a second cable insulator, and a second outer semiconductive layer from its center outwards. The cable intermediate connection structure includes: a conductor connection portion that connects one end of the first cable conductor to one end of the second cable conductor; and an insulation unit that covers the outer periphery of one end of the first outer semiconductive layer. The first cutting end of the first outer semiconductive layer covered by the insulating unit has a ripple width of 6.0 mm or less, and the angle of the first cutting inclined portion extending from the first cutting end to the other end is greater than 5.00 degrees and less than 8.00 degrees. The second cutting end of the second outer semiconductive layer covered by the insulating unit has a ripple width of 6.0 mm or less, and the angle of the second cutting inclined portion extending from the second cutting end to the other end is greater than 5.00 degrees and less than 8.00 degrees.

[0041] First, the method for forming the intermediate cable connection structure of the embodiment will be explained.

[0042] Figure 1 This is a longitudinal sectional view illustrating an example of a cable intermediate connection structure according to an embodiment.

[0043] Figure 2 yes Figure 1 An enlarged cross-sectional view of the intermediate connection structure of the cable. Figure 3 This is a side view showing an example of one end of the first power cable obtained through the first power cable cutting process. Figure 4 yes Figure 3 An enlarged side view of one end of the first power cable. Figure 5 This is a side view showing an example of one end of a second power cable obtained through the second power cable cutting process. Figure 6 yes Figure 5 An enlarged side view of one end of the second power cable.

[0044] It should be noted that, Figure 1 For convenience, the first cable conductor 11, first cable insulator 12, first outer semiconducting layer 13, first semiconducting tape layer 14, first cable shielding layer 15, and first cable sheath 16 of the first power cable 10, and the second cable conductor 21, second cable insulator 22, second outer semiconducting layer 23, second semiconducting tape layer 24, second cable shielding layer 25, and second cable sheath 26 of the second power cable 20 are shown in side views. Additionally, for convenience, Figure 4 The first outer semiconductive layer 13 is shown in perspective view. Figure 6 The image shows a portion of the second outer semiconductive layer 23 in perspective view. Figure 7 The semiconducting part 8 is shown in perspective view.

[0045] The cable intermediate connection structure 1 of the embodiment is formed by connecting one end of the first power cable 10 to one end of the second power cable 20. One end of the first power cable 10 refers to the side connected to the second power cable 20 when the cable intermediate connection structure 1 is formed, and the other end of the first power cable 10 refers to the side not connected to the second power cable 20 when the cable intermediate connection structure 1 is formed. Similarly, one end of the second power cable 20 refers to the side connected to the first power cable 10 when the cable intermediate connection structure 1 is formed, and the other end of the second power cable 20 refers to the side not connected to the first power cable 10 when the cable intermediate connection structure 1 is formed.

[0046] The first power cable 10 comprises at least a first cable conductor 11, a first cable insulator 12, and a first outer semiconductive layer 13 extending from its center outwards. The first cable conductor 11 extends axially (lengthwise) toward the first power cable 10. The first cable insulator 12 covers the outer side of the first cable conductor 11. The first outer semiconductive layer 13 covers the outer side of the first cable insulator 12. An inner semiconductive layer (not shown) is provided on the inner periphery of the first cable insulator 12. Furthermore, the first power cable 10 comprises, in sequence outside the first outer semiconductive layer 13, a first semiconductive strip layer 14, a first cable shielding layer 15, and a first cable sheath 16.

[0047] The first cable conductor 11 is made of highly conductive metals such as copper, copper alloys, aluminum, and aluminum alloys. The first cable insulation 12 is made of highly insulating resins such as cross-linked polyethylene. The inner semiconductive layer, the first outer semiconductive layer 13, and the first semiconductive tape layer 14 are made of semiconductive resins. The first cable shielding layer 15 is made of highly conductive metals such as copper, copper alloys, aluminum, and aluminum alloys. The first cable sheath 16 is made of resins such as polyethylene or polyvinyl chloride.

[0048] The second power cable 20 is the same as the first power cable 10. The first power cable 10, the first cable conductor 11, the first cable insulator 12, the first outer semiconductive layer 13, the first semiconductive tape layer 14, the first cable shielding layer 15 and the first cable sheath 16 are respectively replaced by the second power cable 20, the second cable conductor 21, the second cable insulator 22, the second outer semiconductive layer 23, the second semiconductive tape layer 24, the second cable shielding layer 25 and the second cable sheath 26.

[0049] The method for forming the cable intermediate connection structure 1 according to the embodiment includes a first power cable cutting step, a second power cable cutting step, a connection step, and an installation step.

[0050] In the first power cable cutting process, for the first power cable 10 with the first outer semiconductive layer 13 exposed at one end, a cutter is used to perform staged stripping and cutting from one end of the first power cable 10 to the other end. By using the staged stripping and cutting with the cutter, the first power cable 10 is continuously cut from one end to the other end in the following manner to form... Figures 3-4 The first cutting end 40 and the first cutting inclined portion 41 are shown. That is, using a cutter, all of the first outer semiconductive layer 13 and the first cable insulation 12 are cut from one end of the first power cable 10 toward the other end, exposing one end of the first cable conductor 11. Then, all of the first outer semiconductive layer 13 and a certain amount of the first cable insulation 12 are cut from one end of the first cable insulation 12 toward the other end, exposing one end of the first cable insulation 12. Then, the amount of cutting of the first outer semiconductive layer 13 is reduced in stages from one end of the first outer semiconductive layer 13 toward the other end, the cutter is stopped, and the staged peeling cut ends.

[0051] By performing a step-by-step stripping and cutting on one end of the first power cable 10 in the manner described above, one end of the first cable conductor 11 and one end of the first cable insulator 12 are exposed on one end of the first power cable 10, and a first cutting end 40 and a first cutting inclined portion 41 are formed on one end of the first outer semiconductive layer 13.

[0052] like Figure 4 As shown, the first cut end 40 of the first outer semiconductive layer 13 is located on the side (front side) opposite to the second power cable 20, and is the leading edge portion of the first outer semiconductive layer 13. When viewed from the radial outside of the first power cable 10, the first cut end 40 has a wavy shape that meanders across the circumferential extension of the first power cable 10 while traveling towards one end and the other end.

[0053] like Figure 4As shown, in the first cutting end 40, the axial distance between the portion of the first power cable 10 closest to the second power cable 20 and the portion furthest from the second power cable 20, i.e., the fluctuation width a1 of the first cutting end 40, is 6.0 mm or less. The fluctuation width a1 of the first cutting end 40 is the shortest distance between the imaginary reference circle c1 passing through the portion of the first cutting end 40 closest to the second power cable 20 and the imaginary reference circle c2 passing through the portion of the first cutting end 40 furthest from the second power cable 20. It should be noted that the imaginary reference circles c1 and c2 mentioned here refer to the outer circumference of the first cable insulator 12 located on a section perpendicular to the central axis of the first power cable 10.

[0054] If the fluctuation width a1 of the first cutting end 40 is greater than 6.0 mm, the first cutting end 40 functions as a protrusion of the first outer semiconductive layer 13 in the upright portion of the stress cone constituting the insulation unit 3. In this case, electric field concentration occurs near the first cutting end 40, making insulation breakdown of the cable intermediate connection structure 1 more likely. When the fluctuation width a1 is 6.0 mm or less, the electric field concentration near the first cutting end 40 is suppressed, thus suppressing insulation breakdown of the cable intermediate connection structure 1. From this perspective, a fluctuation width a1 of 6.0 mm or less is preferred, preferably 5.0 mm or less.

[0055] like Figure 4 As shown, the first cutting inclined portion 41 of the first outer semiconductive layer 13 extends from the end of the first outer semiconductive layer 13, i.e., the first cutting end 40, towards the other end of the first power cable 10. As described above, in the first power cable cutting process, since the cutting amount of the first outer semiconductive layer 13 is reduced in stages from the end of the first outer semiconductive layer 13 towards the other end, the thickness of the first outer semiconductive layer 13 at one end gradually increases towards the other end, forming the first cutting inclined portion 41 with an angle θ1.

[0056] Regarding the standing angle θ1 of the first cutting inclined section 41, it is in Figure 4 In the longitudinal section along the axial direction of the cable intermediate connection structure 1 shown, the angle formed by the straight line connecting the outer surface position P1 of the first cutting inclined portion 41 20mm away from the starting position P of the first cutting inclined portion 41 towards the other end of the first power cable 10, and the straight line connecting the inner surface position P2 of the first cutting inclined portion 41 20mm away from the starting position P of the first cutting inclined portion 41 towards the other end of the first power cable 10.

[0057] Regarding the first cutting end 40 and the first cutting inclined portion 41 formed by using a cutter to perform staged stripping and cutting of the first power cable 10, there is a correlation between the fluctuation width a1 of the first cutting end 40 and the standing angle θ1 of the first cutting inclined portion 41. If the degree to which the cutting amount of the first outer semiconductive layer 13 is reduced in stages using the cutter is decreased, and the standing angle θ1 is decreased to form the first cutting inclined portion 41, the fluctuation width a1 of the first cutting end 40 tends to increase. Conversely, if the degree to which the cutting amount of the first outer semiconductive layer 13 is reduced in stages using the cutter is increased, and the standing angle θ1 is increased to form the first cutting inclined portion 41, the fluctuation width a1 of the first cutting end 40 tends to decrease.

[0058] The standing angle θ1 of the first cutting tilt portion 41 in the first outer semiconductive layer 13 is greater than 5.00 degrees and less than 8.00 degrees. When the standing angle θ1 of the first cutting tilt portion 41 is greater than 8.00 degrees, the following will be applied during the installation process: Figure 8 When the hollow cylindrical insulating unit 3, which has its inner circumferential surface 3a enlarged and maintained, is shown, the shrinkage of the insulating unit 3 cannot follow the shape of the first cutting inclined portion 41, and voids are easily formed inside the insulating unit 3. Moreover, since voltage is applied to the voids and discharge occurs, insulation breakdown of the cable intermediate connection structure 1 is likely to occur. If the standing angle θ1 of the first cutting inclined portion 41 is 8.00 degrees or less, the formation of voids inside the insulating unit 3 can be suppressed, and thus insulation breakdown of the cable intermediate connection structure 1 can be suppressed. From this point of view, the standing angle θ1 of the first cutting inclined portion 41 is 8.00 degrees or less, preferably 7.00 degrees or less.

[0059] Furthermore, when the angle θ1 of the first cutting tilt portion 41 is less than 5.00 degrees, the undulation width a1 of the first cutting end 40 increases, and as a result, the undulation width a1 easily becomes greater than 6.0 mm. Therefore, electric field concentration occurs near the first cutting end 40, making insulation breakdown of the cable intermediate connection structure 1 more likely. If the angle θ1 of the first cutting tilt portion 41 is greater than 5.00 degrees, the undulation width a1 of the first cutting end 40 decreases, thus suppressing insulation breakdown of the cable intermediate connection structure 1.

[0060] Furthermore, as described above, in the staged peeling cut using a cutter, if the fluctuation width a1 of the first cutting end 40 is small, the standing angle θ1 of the first cutting tilt portion 41 will become large. If the standing angle θ1 of the first cutting tilt portion 41 is too large, insulation breakdown will easily occur due to the formation of a pore on the inner side of the insulating unit 3. Therefore, the fluctuation width a1 of the first cutting end 40 is preferably 1.0 mm or more.

[0061] Regarding the configuration of the cutter used in the first power cable cutting process, there are no particular limitations as long as it can perform staged stripping and cutting on one end of the first power cable 10 exposed by the first outer semiconductive layer 13, exposing one end of the first cable conductor 11 and the first cable insulator 12, and forming a first cutting end 40 with a fluctuation width a1 within the aforementioned range and a first cutting inclined portion 41 with an angle θ1 within the aforementioned range.

[0062] As an example, the cutter used in the first power cable cutting process has multiple rollers arranged circumferentially and a plate-shaped cutting edge. The cutting edge cuts into the outer periphery of the first outer semiconductive layer 13, and while the rollers of the cutter move from one end of the first power cable 10 to the other end, the cutting edge rotates circumferentially along the first outer semiconductive layer 13, thereby performing a staged peeling cut on one end of the first power cable 10. To form the first cutting end 40 and the first cutting inclined portion 41, the cutting edge face is inclined at a predetermined angle relative to the axial direction of the first power cable 10. Therefore, the type of cutting edge tip is preferably a cutting edge.

[0063] Regarding the first power cable 10 with the first outer semiconductive layer 13 exposed at one end, prepared in the first power cable cutting process, it can be obtained, for example, by sequentially removing the first cable sheath 16, the first cable shielding layer 15, and the first semiconductive strip layer 14 from the outside of the first power cable 10 using a sheath cutter, a knife, or the like.

[0064] The second power cable cutting process is basically the same as the first power cable cutting process. The components of the first power cable cutting process, namely the first power cable 10, the first cable conductor 11, the first cable insulator 12, the first outer semiconductive layer 13, the first semiconductive strip layer 14, the first cable shield layer 15, the first cable sheath 16, the first cutting end 40, the first cutting inclined portion 41, the wave width a1, the imaginary reference circle c1, the imaginary reference circle c2, the standing angle θ1, the outer surface position P1, and the inner surface position P2, are respectively replaced by the components of the second power cable 20, the second cable conductor 21, the second cable insulator 22, the second outer semiconductive layer 23, the second semiconductive strip layer 24, the second cable shield layer 25, and the second cable sheath 26, the second cutting end 50, the second cutting inclined portion 51, the wave width a2, the imaginary reference circle c3, the imaginary reference circle c4, the standing angle θ2, the outer surface position P3, and the inner surface position P4.

[0065] Figures 5-6 The second power cable cutting process shown can be performed before the first power cable cutting process, after the first power cable cutting process, or simultaneously with the first power cable cutting process.

[0066] Figure 7 This is a side view illustrating an example of a connection process. (As shown) Figure 7 As shown, in the connection process performed after the first power cable cutting process and the second power cable cutting process, the conductor connection part 2 connects the end of the first cable conductor 11 exposed from the first power cable 10 in the first power cable cutting process to the end of the second cable conductor 21 exposed from the second power cable 20 in the second power cable cutting process.

[0067] With one end of the exposed first cable conductor 11 inserted into one end of the conductor connector 2 and one end of the exposed second cable conductor 21 inserted into the other end of the conductor connector 2, the conductor connector 2 electrically connects the first cable conductor 11 of the first power cable 10 and the second cable conductor 21 of the second power cable 20 by compressing the conductor connector 2.

[0068] From the viewpoint of high conductivity and compressibility, the conductor connection portion 2 is preferably made of copper, copper alloy, aluminum, or aluminum alloy. The conductor connection portion 2 is, for example, cylindrical.

[0069] In the installation process following the connection process, such as Figure 7 As shown, a cylindrical semiconducting portion 8 is formed at least on the outer periphery of the conductor connection portion 2, the outer periphery of the exposed portion of the first cable conductor 11, and the outer periphery of the exposed portion of the second cable conductor 21. For example, the semiconducting portion 8 is formed by winding a semiconducting strip. Next, a hollow cylindrical insulating unit 3 is installed in the area extending from the outer periphery of the exposed portion of the first outer semiconducting layer 13 to the outer periphery of the exposed portion of the second outer semiconducting layer 23. Thus, a... Figure 1 The cable intermediate connection structure 1 is shown. It should be noted that... Figure 1 The example shown illustrates that the insulating unit 3 covers the entire exposed portion of the first outer semiconductive layer 13 and the exposed portion of the second outer semiconductive layer 23. However, the insulating unit 3 only needs to cover the exposed portion on one end of the first outer semiconductive layer 13 and the exposed portion on one end of the second outer semiconductive layer 23. A portion of the other end of the exposed portion may not be covered by the insulating unit 3.

[0070] The insulating unit 3 is installed in a state of tight fit with the outer periphery of the semiconductive part 8, the outer periphery of the exposed portion at one end of the first cable insulator 12, the outer periphery of the exposed portion at one end of the first external semiconductive layer 13, the outer periphery of the exposed portion at one end of the second cable insulator 22, and the outer periphery of the exposed portion at one end of the second external semiconductive layer 23 (hereinafter also referred to as the outer periphery of the connecting portion).

[0071] Insulating unit 3 covers the outer periphery of the connection portion between the first power cable 10 and the second power cable 20. Such insulating unit 3 continuously covers the exposed portion from one end of the first outer semiconductive layer 13 to the exposed portion of one end of the second outer semiconductive layer 23.

[0072] The insulating unit 3 is cylindrical and has radial shrinkage. Furthermore, the insulating unit 3 is installed covering the outer periphery of the connecting portion in an expanded-diameter state. Therefore, it is installed in a state where the inner circumferential surface of the insulating unit 3 is tightly fitted to the outer periphery of the connecting portion under the action of the restoring force of the insulating unit 3.

[0073] The insulation unit 3 has a main insulation portion 31, a cylindrical inner circumferential semiconducting portion 32 disposed on the inner circumferential portion of the central part of the main insulation portion 31 along the axial direction of the cable intermediate connection structure 1, end semiconducting portions 33 disposed at both ends of the main insulation portion 31, and a cylindrical outer circumferential semiconducting portion 34 disposed on the outer circumferential portion of the central part of the main insulation portion 31 along the axial direction. The outer circumferential semiconducting portion 34 is configured to contact at least one (or both) of the two end semiconducting portions 33.

[0074] As described above, the first power cable cutting process allows for the continuous exposure of one end of the first cable conductor 11 and one end of the first cable insulator 12 using a cutter, as well as the formation of a first cutting end 40 with a fluctuation width a1 within the aforementioned range and a first cutting inclined portion 41 with an elevation angle θ1 within the aforementioned range. Similarly, the second power cable cutting process allows for the continuous exposure of one end of the second cable conductor 21 and one end of the second cable insulator 22 using a cutter, as well as the formation of a second cutting end 50 with a fluctuation width a2 within the aforementioned range and a second cutting inclined portion 51 with an elevation angle θ2 within the aforementioned range. Therefore, the cable intermediate connection structure 1 can be formed quickly and easily.

[0075] Furthermore, even without performing manual finishing operations such as sanding the insulation surface after exposing the conductor and insulation at one end of the power cable, or smoothing the edges to align the outer semiconductive layer, insulation breakdown of the cable intermediate connection structure 1 can be suppressed. Therefore, the operator can be de-skilled by forming the cable intermediate connection structure 1 quickly and easily.

[0076] It should be noted that, as described above, compared with the past, the fluctuation width of the first cutting end 40 and the second cutting end 50 formed by cutting the first outer semiconductive layer 13 and the second outer semiconductive layer 23 with a cutter can be sufficiently reduced. Therefore, even if the insulator is subsequently ground or the outer semiconductive layer is smoothed, these processes can be performed easily.

[0077] In addition, the cable intermediate connection structure 1 has a first cutting end 40 and a second cutting end 50 with a fluctuation width within the above range, and a first cutting inclined portion 41 and a second cutting inclined portion 51 with an upright angle within the above range. Therefore, the cable intermediate connection structure 1 can suppress insulation breakdown.

[0078] In addition, such as Figures 3-4 As shown, for the end of the first cable insulator 12 exposed by the staged stripping cutting in the first power cable cutting process, the surface roughness Ra of the outer peripheral surface 12a of the exposed portion of the first cable insulator 12 is preferably 40 μm or less. When the surface roughness Ra of the outer peripheral surface 12a of the first cable insulator 12 is 40 μm or less, the amount of pores formed inside the insulation unit 3 is reduced, thus further suppressing insulation breakdown of the cable intermediate connection structure 1. The smaller the surface roughness Ra of the outer peripheral surface 12a, the more effectively insulation breakdown of the cable intermediate connection structure 1 can be suppressed. When the surface roughness Ra of the outer peripheral surface 12a is greater than 40 μm, the outer peripheral surface 12a can be ground to reduce the surface roughness Ra of the outer peripheral surface 12a.

[0079] In addition, the surface roughness Ra of the exposed portion of the second cable insulation 22 of the second power cable, namely the outer peripheral surface 22a, is the same as that of the first power cable 10.

[0080] The surface roughness Ra of the outer peripheral surface 12a of the first cable insulator 12 and the outer peripheral surface 22a of the second cable insulator 22 is the average value obtained by measuring the surface roughness at several points (0°, 90° direction) in the axial direction using a surface roughness meter.

[0081] Furthermore, regarding the method for forming the intermediate cable connection structure in the embodiment, it is preferable that, in the installation process, after applying insulating oil to the outer peripheral surface of the exposed portion from one end of the first outer semiconductive layer 13 to the outer peripheral surface of the exposed portion from one end of the second outer semiconductive layer 23, the insulating unit 3 is installed.

[0082] If an insulating unit 3 is installed on the outer periphery of the connection portion coated with insulating oil, the insulating oil will fill any pores formed inside the insulating unit 3. Therefore, insulation breakdown of the cable intermediate connection structure 1 can be further suppressed.

[0083] Furthermore, the applied insulating oil reduces the coefficient of friction on the outer peripheral surfaces of the connecting portions of the insulating unit 3. During installation, the movement of the insulating unit 3 becomes easier, thus facilitating its placement in the desired location.

[0084] Based on the above points, fluorinated oil is preferred as the insulating oil. Alternatively, silicone oil can also be used.

[0085] In addition, the insulation breakdown strength of the insulating oil is preferably 12kV / mm or higher. If the insulation breakdown strength of the insulating oil is within the above range, the insulation breakdown of the intermediate connection structure 1 of the cable can be further suppressed.

[0086] In addition, the dynamic viscosity of the insulating oil is preferably 1000 mm. 2 / s or more 1500mm 2 / s or less. Regarding the dynamic viscosity of the insulating oil, if it is 1000 mm... 2 A speed of 1 / s or higher can suppress the sagging of insulating oil caused by gravity. If it is 1500mm... 2 A viscosity below / s can improve the coatability of the insulating oil. The dynamic viscosity of the insulating oil mentioned above is the dynamic viscosity of the insulating oil at 20℃.

[0087] in addition, Figure 8 This is a schematic diagram illustrating an example of the installation process for installing an insulating unit with an expansion diameter retaining member. The insulating unit 3 is formed of silicone rubber. In the installation process, preferably, an expansion diameter retaining member 60, formed by winding the inner circumferential surface 3a of the insulating unit 3 into a spiral shape, is pulled out from the insulating unit 3, and the insulating unit 3 is then installed. The expansion diameter retaining member 60 is a spiral core.

[0088] exist Figure 8 In the installation process shown, firstly, the insulation unit 3, with its inner circumferential surface 3a enlarged by the diameter-enlarging retaining member 60, is moved to the connection point between the first power cable 10 and the second power cable 20. Next, by pulling one end of the diameter-enlarging retaining member 60, which is spirally wound around the inner circumferential surface 3a, from the insulation unit 3, the diameter of the inner circumferential surface 3a of the insulation unit 3 is reduced, allowing for easy installation in a state of tight fit with the outer circumference of the connection point. Therefore, the cable intermediate connection structure 1 can be formed more quickly and easily.

[0089] Furthermore, in the method of moving the insulating unit 3 pre-installed on the first power cable 10 or the second power cable 20 to the connection portion, foreign objects sometimes intrude into the inside of the insulating unit 3 when the installed insulating unit 3 is moved. On the other hand, in Figure 8 The installation process shown can suppress the intrusion of such foreign objects.

[0090] Thus, the insulation unit 3, which was expanded in diameter before installation, is reduced in diameter and installed in a state of tight fit with the outer periphery of the connection portion of the first power cable 10 and the second power cable 20. When the insulating oil is fluorinated oil, considering the conformability of the insulation unit 3 to the shape of the connection portion, i.e., Young's modulus, it is preferable that the insulation unit 3 is formed of silicone rubber. Alternatively, when the insulating oil is silicone oil, the insulation unit 3 is preferably formed of ethylene propylene rubber (EP rubber).

[0091] Additionally, there exists on the other end side of the first cutting inclined portion 41 Figure 3 The step difference portion 42 shown has a larger step difference on the other end side, and exists on the other end side of the second cutting inclined portion 51. Figure 5 In the case of the other end step difference portion 52 with a large step difference shown, it is preferable to have a removal process before the installation process, in which at least one of the other end step difference portion 42 of the first cutting inclined portion 41 and the other end step difference portion 52 of the second cutting inclined portion 51 is removed.

[0092] In the first power cable cutting process, when the staged stripping cut of the cutter, which moves from one end of the first power cable 10 towards the other end, ends, a step portion 42 on the other end side may sometimes be formed at the position where the cutting edge of the circumferentially rotating cutter stops. This step portion 42 on the other end side of the first cutting inclined section 41 is not formed over the entire circumferential direction, but rather locally. Similarly, in the second power cable cutting process, as in the first power cable cutting process, a step portion 52 on the other end side of the second cutting inclined section 51 may sometimes be formed.

[0093] By removing the step portion 42 on the other side of the first cutting inclined portion 41 and the step portion 52 on the other side of the second cutting inclined portion 51, the amount of pores formed inside the insulation unit 3 is reduced, thereby further suppressing insulation breakdown of the cable intermediate connection structure 1. For example, the operator removes the step portion 42 and the step portion 52 on the other side by hand using a glass plate.

[0094] As described above, since the step difference portion 42 and the step difference portion 52 at the other end are formed at the stop position of the cutting edge, the portions where the step difference portion 42 and the step difference portion 52 are formed are localized and easily determined. Therefore, the removal process does not depend on the operator's skill level.

[0095] Next, the cable intermediate connection structure of the embodiment will be described.

[0096] The cable intermediate connection structure 1 of the embodiment is formed by the method for forming the cable intermediate connection structure described in the above embodiment. For example... Figure 1As shown, the cable intermediate connection structure 1 is a connection structure that connects one end of the first power cable 10 to one end of the second power cable. The cable intermediate connection structure 1 includes a conductor connection portion 2 and an insulation unit 3.

[0097] The conductor connection part 2 that constitutes the intermediate connection structure 1 of the cable connects one end of the first cable conductor 11 in the first power cable 10 and one end of the second cable conductor 21 in the second power cable 20.

[0098] The insulating unit 3 extends from the outer periphery of one end of the first outer semiconductive layer 13, which includes the first cutting end 40 and the first cutting inclined portion 41, to the outer periphery of one end of the second outer semiconductive layer 23, which includes the second cutting end 50 and the second cutting inclined portion 51.

[0099] The undulation width a1 of the first cutting end 40 covered by the insulation unit 3 is 6.0 mm or less, preferably 5.0 mm or less. If the undulation width a1 of the first cutting end 40 is 6.0 mm or less, the electric field concentration near the first cutting end 40 is suppressed, thus suppressing the insulation breakdown of the cable intermediate connection structure 1.

[0100] The angle θ1 of the first cutting inclined portion 41 covered by the insulating unit 3 is greater than 5.00 degrees and less than 8.00 degrees. If the angle θ1 of the first cutting inclined portion 41 is less than 8.00 degrees, the formation of pores towards the inside of the insulating unit 3 can be suppressed, thus suppressing insulation breakdown of the cable intermediate connection structure 1. From this point of view, the angle θ1 of the first cutting inclined portion 41 is less than 8.00 degrees, preferably less than 7.00 degrees.

[0101] If the standing angle θ1 of the first cutting tilt portion 41 is greater than 5.00 degrees, the fluctuation width a1 of the first cutting end 40 formed by the cutter becomes smaller, thus suppressing insulation breakdown of the cable intermediate connection structure 1. From this point of view, the standing angle θ1 of the first cutting tilt portion 41 is greater than 5.00 degrees.

[0102] The undulation width a2 of the second cutting end 50 is the same as the undulation width a1 of the first cutting end 40. In addition, the standing angle θ2 of the second cutting tilt portion 51 is the same as the standing angle θ1 of the first cutting tilt portion 41.

[0103] It should be noted that, as Figure 1 As shown, the cable intermediate connection structure 1 may also include, from the inside, a shielding layer 4, a protective layer 5, and a metal tube 7 made of copper or other metal, in a range extending from the outer periphery of the exposed portion of the first cable shielding layer 15 to the outer periphery of the exposed portion of the second cable shielding layer 25, on the outer side of the insulation unit 3. The interior of the metal tube 7 may be as follows: Figure 1 The composite portion 6 is formed by filling with a composite material as shown, or it can be formed by filling with air without filling with a composite material (not shown). Additionally, the cable intermediate connection structure 1 may also include a conductor portion 9 made of metal that connects one end of the metal tube 7 (the end on the side of the first power cable 10) to the first cable shielding layer 15, and the other end of the metal tube 7 (the end on the side of the second power cable 20) to the second cable shielding layer 25. Furthermore, the cable intermediate connection structure 1 may also include anti-corrosion portions 70 formed by filling with resin and winding with tape at both ends of the metal tube 7, so that each opening is sealed between itself and the first cable sheath 16 and the second cable sheath 26.

[0104] Alternatively, the cable intermediate connection structure 1 may also have a semiconductive strip 35 provided near one end of the main insulation portion 31 (near the end on the side of the first power cable 10) in a gap located inside the shielding layer 4, so that the first outer semiconductive layer 13, the first semiconductive strip layer 14, and the end semiconductive portion 33 are in electrical contact with each other and fill the gap. Alternatively, the cable intermediate connection structure 1 may also have a semiconductive strip 35 provided near the other end of the main insulation portion 31 (near the end on the side of the second power cable 20) in a gap located inside the shielding layer 4.

[0105] The cable intermediate connection structure 1 having the above-described configuration is preferably a room-temperature shrinkable joint (CSJ) that requires suppression of insulation breakdown and quick and easy formation. Furthermore, the first power cable 10 and the second power cable 20 connected by the cable intermediate connection structure 1 are preferably cross-linked polyethylene insulated vinyl sheathed cables (CV cables). Additionally, the withstand voltage of the first power cable 10 and the second power cable 20 is preferably 154 kV or less.

[0106] Furthermore, while the above description focused on the application of the present invention to the method for forming a cable intermediate connection structure and the cable intermediate connection structure itself, the present invention can also be applied to the method for forming a cable termination connection structure and the cable termination connection structure. When the present invention is applied to the method for forming a cable termination connection structure and the cable termination connection structure, insulation breakdown can be suppressed, and the structure can be formed quickly and easily.

[0107] According to the embodiments described above, by using a cutter to perform the first and second power cable cutting processes, a cable intermediate connection structure can be formed quickly and easily. Furthermore, by ensuring that the undulation widths of the first and second cutting ends, and the elevation angles of the first and second cutting inclination portions meet a predetermined relationship, insulation breakdown of the cable intermediate connection structure can be suppressed.

[0108] It should be noted that the above description shows an example where the first power cable 10, in addition to having a first cable conductor 11, a first cable insulator 12, and a first outer semiconducting layer 13, also has a first semiconducting tape layer 14, a first cable shielding layer 15, and a first cable sheath 16. However, as long as the first power cable 10 has at least the first cable conductor 11, the first cable insulator 12, and the first outer semiconducting layer 13, the configuration of the first power cable 10 is not particularly limited. For example, the first power cable 10 may also omit the first cable sheath 16, but have the first cable conductor 11, the first cable insulator 12, the first outer semiconducting layer 13, the first semiconducting tape layer 14, and the first cable shielding layer 15. The same applies to the second power cable 20.

[0109] The embodiments have been described above, but the present invention is not limited to the above embodiments, and includes all the concepts and methods contained in the claims, and various changes can be made within the scope of the present invention.

[0110] Example

[0111] The following describes the embodiments and comparative examples, but the present invention is not limited to these embodiments.

[0112] (Examples 1-10 and Comparative Examples 1-2)

[0113] Prepare 66kV cables and insulation units. Using a cutter (SH50, Hivotec), perform staged stripping and cutting on the first power cable with exposed first outer semiconductive layer at one end, forming a first cut end with a ripple width a1 as shown in Table 1 and a first cut inclined portion with an elevation angle θ1. Similarly, using a cutter (SH50, Hivotec), perform staged stripping and cutting on the second power cable with exposed second outer semiconductive layer at one end, forming a second cut end with a ripple width a2 as shown in Table 1 and a second cut inclined portion with an elevation angle θ2. Next, connect the first and second power cables with conductor connectors. Then, after covering the conductor connectors with semiconductive portions, apply fluorinated oil with a dynamic viscosity of 1300 at 20°C to the area extending from the outer periphery of the exposed portion of the first outer semiconductive layer to the outer periphery of the exposed portion of the second outer semiconductive layer. Next, install the insulation unit. Thus, a [structure / component] is formed. Figure 1 The cable intermediate connection structure is shown.

[0114] It should be noted that in Comparative Example 1, cable intermediate connection structures of Comparative Example 1-1 and Comparative Example 1-2 were formed, in which the undulation width a1 of the first cutting end was greater than 6.0 mm. In addition, in Comparative Example 2, cable intermediate connection structures of Comparative Example 2-1 and Comparative Example 2-2 were formed, in which the standing angle θ1 of the first cutting inclined portion was greater than 8.00 degrees.

[0115] As insulation breakdown tests, commercial frequency AC voltage (AC) tests and lightning pulse voltage (lightning lmp) tests were conducted. The results are shown in Table 1.

[0116] [Table 1]

[0117]

[0118] As shown in Table 1, in Examples 1 to 10, since the fluctuation width of the first cutting end and the second cutting end, and the standing angle of the first cutting tilt portion and the second cutting tilt portion meet the specified relationship, insulation breakdown of the intermediate connection structure of the cable can be suppressed.

[0119] On the other hand, in Comparative Examples 1 and 2, the fluctuation width of the first and second cutting ends, as well as the vertical angle of the first and second cutting inclination portions, did not meet the specified relationship. Therefore, insulation breakdown of the cable intermediate connection structure could not be suppressed, and the withstand voltage of 130kV for the nominal voltage 66kV commercial frequency voltage room temperature test and the withstand voltage of 485kV for the nominal voltage 66kV lightning pulse room temperature test, as described in the Electrical Specifications Institute of the Chinese Electrical Society standard JEC-3408, could not be achieved. For the cable intermediate connection structure of Comparative Example 1-1, since it broke down at 120kV in the commercial frequency AC voltage (AC) test, the lightning pulse voltage (lightning lmp) test could not be performed. Therefore, as another sample with a similar configuration, the lightning pulse voltage (lightning lmp) test was performed on the cable intermediate connection structure of Comparative Example 1-2, but since it broke down at 430kV, the commercial frequency AC voltage (AC) test could not be performed. Similarly, for the cable intermediate connection structure of Comparative Example 2-1, a lightning pulse voltage (LMP) test could not be performed because it broke down at 120 kV during the commercial frequency AC voltage (AC) test. Therefore, as another sample with a similar configuration, a lightning pulse voltage (LMP) test was performed on the cable intermediate connection structure of Comparative Example 2-2, but it could not be performed because it broke down at 480 kV.

[0120] Explanation of reference numerals in the attached figures

[0121] 1. Cable intermediate connection structure

[0122] 2 Conductor connection part

[0123] 3 Insulation Units

[0124] 3a Inner peripheral surface of the insulation unit

[0125] 4. Shielding layer

[0126] 5 protective layers

[0127] 6. Complex section

[0128] 7. Metal pipes

[0129] 8 Semiconducting parts

[0130] 9. Conductor section

[0131] 10. First Power Cable

[0132] 11. First cable conductor

[0133] 12. First cable insulation

[0134] 12a The outer circumference of the exposed portion of the first cable insulation

[0135] 13 First outer semiconductive layer

[0136] 14 First Semiconducting Band Layer

[0137] 15 First cable shielding layer

[0138] 16 First cable sheath

[0139] 20. No. 2 power cable

[0140] 21. Second cable conductor

[0141] 22. Cable Insulation

[0142] 22a Outer circumference of the exposed portion of the second cable insulation

[0143] 23 Second outer semiconducting layer

[0144] 24 Second Semiconducting Band Layer

[0145] 25 Second cable shielding layer

[0146] 26. Second cable sheath

[0147] 31 Main insulation section

[0148] 32 Inner peripheral semiconductor part

[0149] 33 End Semiconductor

[0150] 34 Peripheral Semiconductor

[0151] 35 Semiconducting strip

[0152] 40 First cutting end

[0153] 41 First cutting inclined section

[0154] 42 The other end side step difference section

[0155] 50 Second cutting end

[0156] 51 Second cutting inclined section

[0157] 52 The other end side step difference section

[0158] 60. Expanded diameter retaining component

[0159] 70 Corrosion Protection Department

Claims

1. A method for forming a cable intermediate connection structure, wherein the cable intermediate connection structure connects one end of a first power cable to one end of a second power cable, the first power cable having at least a first cable conductor, a first cable insulator, and a first outer semiconductive layer from its center outwards, and the second power cable having at least a second cable conductor, a second cable insulator, and a second outer semiconductive layer from its center outwards, the method being characterized by having: The first power cable cutting process, in which... For the first power cable with the first outer semiconductive layer exposed at one end, a cutter is used to perform a staged stripping and cutting of the first power cable from one end to the other end, exposing one end of the first cable conductor and one end of the first cable insulator. A first cutting end and a first cutting inclined portion are formed at one end of the first outer semiconductive layer. The first cutting end has a ripple width of 1.0 mm to 6.0 mm, and the first cutting inclined portion extends from the first cutting end to the other end and has an angle of greater than 5.00 degrees and less than 8.00 degrees. The second power cable cutting process involves using a cutter to perform a staged stripping cut on one end of the second power cable, exposing one end of the second cable conductor and one end of the second cable insulator. A second cutting end and a second cutting inclined portion are formed on one end of the second outer semiconductive layer. The second cutting end has a ripple width of 1.0 mm to 6.0 mm, and the second cutting inclined portion extends from the second cutting end to the other end and has an angle of greater than 5.00 degrees and less than 8.00 degrees. The connection process includes connecting the end of the first cable conductor exposed in the first power cable cutting process and the end of the second cable conductor exposed in the second power cable cutting process using a conductor connection part; and In the installation process, a cylindrical semiconducting portion is formed at least around the outer periphery of the conductor connection, the outer periphery of the exposed portion of the first cable conductor, and the outer periphery of the exposed portion of the second cable conductor, and a cylindrical insulating unit is installed extending from the outer periphery of the exposed portion of the first outer semiconducting layer to the outer periphery of the exposed portion of the second outer semiconducting layer.

2. The method for forming the cable intermediate connection structure as described in claim 1, wherein, In the installation process, after applying insulating oil across the outer peripheral surface of the exposed portion of the first outer semiconductive layer to the outer peripheral surface of the exposed portion of the second outer semiconductive layer, the insulating unit is installed.

3. The method for forming the intermediate connection structure of the cable as described in claim 2, wherein, The insulating oil is fluorinated oil.

4. The method for forming the cable intermediate connection structure as described in any one of claims 1 to 3, wherein, The insulating unit is formed of silicone rubber. In the installation process, the diameter expansion retaining component is extracted from the insulating unit and installed on the insulating unit. The diameter expansion retaining component is formed by winding the inner circumferential surface of the insulating unit into a spiral shape and expands and retains the inner circumferential surface of the insulating unit.

5. The method for forming the cable intermediate connection structure as described in claim 1, wherein, Prior to the installation process, there is a removal process that removes at least one of the step difference portion on the other end of the first cutting inclined portion and the step difference portion on the other end of the second cutting inclined portion.

6. A cable intermediate connection structure connecting one end of a first power cable to one end of a second power cable, wherein the first power cable has at least a first cable conductor, a first cable insulator, and a first outer semiconductive layer from its center outwards, and the second power cable has at least a second cable conductor, a second cable insulator, and a second outer semiconductive layer from its center outwards, the cable intermediate connection structure being characterized by comprising: A conductor connector that connects one end of the first cable conductor to one end of the second cable conductor; and An insulating unit extends from the outer periphery of one end of the first outer semiconducting layer to the outer periphery of one end of the second outer semiconducting layer. in, The undulation width of the first cutting end on one end side of the first outer semiconductive layer covered by the insulating unit is more than 1.0 mm and less than 6.0 mm, and the standing angle of the first cutting inclined portion extending from the first cutting end to the other end side is greater than 5.00 degrees and less than 8.00 degrees. The undulation width of the second cutting end on one end side of the second outer semiconductive layer covered by the insulating unit is more than 1.0 mm and less than 6.0 mm, and the standing angle of the second cutting inclined portion extending from the second cutting end to the other end side is greater than 5.00 degrees and less than 8.00 degrees.

Images