Cable connection structure, connection power cable, and method for manufacturing cable connection structure

Abstract

To stably secure an insulation property of a cable connection structure.SOLUTION: A cable connection structure includes a first power cable and a second power cable, a cylindrical sleeve for connecting the conductor of the first power cable and the conductor of the second power cable, an insulation unit which is provided so as to cover the outer periphery of the region including the sleeve and maintains an insulation property in the periphery of the sleeve, and a protection part for coating the outer peripheries of the insulation unit, a part of the first power cable and a part of the second power cable, wherein the protection part includes a first shield layer for electrically shielding the part of the first power cable and the insulation unit, a second shield layer which is separated so as to sandwich a predetermined shield separation part in the axial direction of the conductor from the first shield layer and electrically shields a part of the second power cable, an insulating intermediate layer which contains an insulating resin, and continuously coats the outer periphery of the first shield layer, the outer periphery of the insulation unit exposed to the separation part, and the outer periphery of the second shield layer, and a water shielding layer which contains a water-shielding metal sheet and coats the outer periphery of the insulation intermediate layer, and the insulating intermediate layer is composed of a normal temperature shrinkable tube which is elastically shrunk at a normal temperature.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a cable connection structure, a connecting power cable, and a method for manufacturing the cable connection structure.

Background Art

[0002] As cable connection structures, various structures have been developed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to stably ensure the insulation of a cable connection structure.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, a first power cable and a second power cable each having a conductor, a cylindrical sleeve connecting the conductor of the first power cable and the conductor of the second power cable, an insulating unit provided so as to cover the outer periphery of the region including the sleeve and maintaining the insulation around the sleeve, a protective part covering the outer periphery of the insulating unit, a part of the first power cable, and a part of the second power cable, are provided, the protective part includes a first shielding layer that electrically shields a part of the first power cable and the insulating unit, a second shielding layer that is separated from the first shielding layer by a predetermined shielding separation part in the axial direction of the conductor and electrically shields a part of the second power cable, An insulating intermediate layer that includes an insulating resin and continuously covers the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation portion, and the outer periphery of the second shielding layer; A water shielding layer that includes a water shielding metal sheet and covers the outer periphery of the insulating intermediate layer; and has The insulating intermediate layer is composed of a normal temperature shrinkable tube that elastically shrinks at normal temperature. A cable connection structure is provided.

Advantages of the Invention

[0006] According to the present disclosure, the insulation of the cable connection structure can be stably ensured.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0008] [Description of Embodiments of the Present Disclosure] [Findings Obtained by the Inventor] First, the findings obtained by the inventor will be described.

[0009] In an intermediate connection portion where a pair of power cables are connected, it may be necessary to separate the grounding systems in the pair of power cables. Such a connection portion is referred to as an "insulating connection portion".

[0010] In the insulating connection part, a first shielding layer is provided so as to electrically shield a part of the first power cable and an insulating unit covering the conductor connection part. On the other hand, a second shielding layer is provided so as to electrically shield a part of the second power cable. The second shielding layer is provided at a distance from the first shielding layer with a predetermined shielding separation part interposed therebetween in the axial direction of the conductor. Thereby, electrical interruption (also referred to as "insulation cutting property") between the first shielding layer and the second shielding layer is ensured.

[0011] By providing such an insulating connection part in each of the three-phase power cables and cross-bonding and grounding the shielding layers of the three-phase power cables, the induced voltage generated in the shielding layer can be suppressed.

[0012] In the above-mentioned insulating connection part, as configurations outside the first shielding layer and the second shielding layer, for example, the following two configurations have been developed.

[0013] (Configuration using a conventional metal pipe) In a conventional insulating connection part, for example, a metal pipe was provided so as to protect the outside of an insulating unit covering the conductor connection part. The metal pipe ensured water shielding property.

[0014] In a conventional insulating connection part, a cylindrical insulator was interposed at an intermediate position in the axial direction of the metal pipe to separate the metal pipe in the region close to the first power cable and the metal pipe in the region close to the second power cable. With such a configuration, both water shielding property and electrical interruption were achieved.

[0015] In such a configuration using a metal pipe, an insulating compound was filled in the gap between each shielding layer and the metal pipe. Thereby, the insulation between each shielding layer and the metal pipe (hereinafter also referred to as "insulation between the shielding layer and the ground") and the insulation between the first shielding layer and the second shielding layer (hereinafter also referred to as "insulation between the shielding layers") were ensured.

[0016] (Configuration using a water shielding layer) The conventional configuration using the above metal pipe had a complex and heavy structure. Therefore, the construction of the insulation connection part was difficult, and the cost related to the insulation connection part was increasing.

[0017] In order to solve such problems, in the insulation connection part, a configuration in which the conventional metal pipe is replaced with a water shielding layer including a metal sheet with low water shielding property has been studied.

[0018] In the configuration using the water shielding layer up to now, an insulating tape such as a self-fusing tape was spirally wound around the outer circumferences of the first shielding layer and the second shielding layer separated by a predetermined shielding separation part. The above-mentioned water shielding layer was provided on the outer circumference of the insulating tape.

[0019] In this configuration, the water shielding layer was in contact with the outer circumference of the insulating tape, that is, the metal sheets of each shielding layer and the water shielding layer were close to each other in the thickness direction. However, the metal sheet of the water shielding layer was not connected to any of the shielding layers and was a floating electrode.

[0020] As a result of the inventor's intensive study, it was found that the following problems (i) to (v) occurred in the above configuration.

[0021] (i) In the insulating tape provided between each shielding layer and the water shielding layer, there were thin parts and thick parts depending on the winding method of the insulating tape. Therefore, there were variations in the insulation property of the insulating tape.

[0022] When there were variations in the insulation property of the insulating tape, the insulation property (insulation property between the floating electrode and the ground) between the metal sheet of the water shielding layer as a floating electrode and each shielding layer decreased through the thin part of the insulating tape. Or, in this case, the insulation property (insulation property between the shields) between the first shielding layer and the second shielding layer decreased from the thin part of the insulating tape through the water shielding layer.

[0023] As described above, in the configuration in which the insulating tape was wound around the outer circumference of the shielding layer, it was difficult to stably ensure the insulation property of the cable connection structure.

[0024] (ii) In order to suppress the variation in the insulation property of the above-mentioned insulating tape, it was necessary to uniformly wind the insulating tape around the outer periphery of the shielding layer. For this reason, excessive skill was required of the operator who wound the insulating tape. As a result, the manufacturing process of the cable connection structure had been complicated and difficult.

[0025] (iii) When winding the above-mentioned insulating tape, air might enter between the insulating tape and the shielding layer. The air layer thus formed had lower insulation property than the insulating tape. Therefore, when an air layer occurred between the insulating tape and the shielding layer, the insulation property between the cable and the ground or the insulation property between the shields was likely to decrease.

[0026] (iv) The self-fusing tape used as the insulating tape tended to be deformed by heating. For this reason, when the heat-shrinkable tube as the water-blocking layer was shrunk by heat, heat was directly applied to the self-fusing tape, and the self-fusing tape might be deformed by heating. As a result, due to the heat deformation of the insulating tape, there was a risk that the above-mentioned insulation property between the cable and the ground or the insulation property between the shields decreased.

[0027] (v) When the cable connection structure generated heat during operation, the insulating unit in the cable connection structure might expand in volume, and the self-fusing tape might be stretched. In this case, over a long period, the surface pressure of the self-fusing tape might decrease. As a result, there was a risk that the above-mentioned insulation property between the cable and the ground or the insulation property between the shields decreased.

[0028] From the above, in the configuration using the water-blocking layer, it had been desired to solve the above-mentioned new problems (i) to (v).

[0029] The following disclosure is based on the above findings found by the present disclosure authors.

[0030] <Embodiments of the Present Disclosure> Next, embodiments of the present disclosure will be listed and described.

[0031] [1] The cable connection structure according to one aspect of the present disclosure is a first power cable and a second power cable each having a conductor, a cylindrical sleeve connecting the conductor of the first power cable and the conductor of the second power cable, an insulating unit provided to cover the outer periphery of the region including the sleeve and maintaining the insulation around the sleeve, a protective part covering the outer peripheries of the insulating unit, a part of the first power cable, and a part of the second power cable, and is provided with the protective part includes a first shielding layer that electrically shields a part of the first power cable and the insulating unit, a second shielding layer that is separated from the first shielding layer by a predetermined shielding separation part in the axial direction of the conductor and electrically shields a part of the second power cable, an insulating intermediate layer containing an insulating resin and continuously covering the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation part, and the outer periphery of the second shielding layer, a water shielding layer containing a water shielding metal sheet and covering the outer periphery of the insulating intermediate layer, and has the insulating intermediate layer is composed of a normal temperature shrinkable tube that elastically shrinks at normal temperature. According to this configuration, the insulation of the cable connection structure can be stably ensured.

[0032] [2] In the cable connection structure according to the above [1], the water shielding layer has a first resin layer covering the inner periphery of the metal sheet and a second resin layer covering the outer periphery of the metal sheet, the first resin layer and the second resin layer contain a resin that shrinks by heating. According to this configuration, even in a configuration where the metal sheet of the water shielding layer and the shielding layer are close to each other, the insulation can be stably ensured.

[0033] [3] In the cable connection structure according to the above [1] or [2], The thickness of the insulating intermediate layer in a cross-section perpendicular to the central axis of the conductor is uniform across the entire circumference of the insulating intermediate layer. According to this configuration, insulation between the conductor and the ground can be stably ensured.

[0034] [4] In the cable connection structure according to any one of [1] to [3] above, The thickness of the insulating intermediate layer in the region overlapping the shielding separation portion is uniform along the axial direction of the conductor. According to this configuration, insulation between the shields can be stably ensured.

[0035] [5] In the cable connection structure according to any one of [1] to [4] above, The insulating intermediate layer has a thickness that can withstand an impulse voltage of 40 kV or more in a state where the insulating intermediate layer is expanded in diameter outside the insulating unit. According to this configuration, insulation breakdown of the cable connection structure can be stably suppressed.

[0036] [6] In the cable connection structure according to any one of [1] to [5] above, The insulating intermediate layer has at least two room-temperature shrinkable tubes that can be separated in the axial direction of the conductor. According to this configuration, the shrinkage operation of the room-temperature shrinkable tube on the insulating unit or the like can be easily performed.

[0037] [7] In the cable connection structure according to any one of [1] to [5] above, The insulating intermediate layer has one room-temperature shrinkable tube that covers the entire outer circumference of the insulating unit in the axial direction of the conductor. According to this configuration, insulation of the cable connection structure can be stably ensured.

[0038] [8] The connected power cable according to still another aspect of the present disclosure is equipped with at least one cable connection structure according to any one of [1] to [7] above. According to this configuration, the insulation of the cable connection structure can be stably ensured.

[0039] [9] A method for manufacturing a cable connection structure according to still another aspect of the present disclosure is as follows. Preparing a first power cable and a second power cable each having a conductor; Connecting the conductor of the first power cable and the conductor of the second power cable with a cylindrical sleeve; Arranging an insulating unit for maintaining the insulation around the sleeve so as to cover the outer periphery of the region including the sleeve; Providing a protective part so as to cover the outer periphery of the insulating unit, a part of the first power cable, and a part of the second power cable; comprising: The step of providing the protective part includes: Providing a first shielding layer so as to electrically shield a part of the first power cable and the insulating unit; Providing a second shielding layer so as to be separated from the first shielding layer by a predetermined shielding separation part in the axial direction of the conductor and electrically shield a part of the second power cable; Providing an insulating intermediate layer containing an insulating resin so as to continuously cover the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation part, and the outer periphery of the second shielding layer; Providing a water shielding layer containing a water shielding metal sheet so as to cover the outer periphery of the insulating intermediate layer; having: In the step of providing the insulating intermediate layer, the insulating intermediate layer is constituted by a normal temperature shrinkable tube that elastically shrinks at normal temperature. According to this configuration, the insulation of the cable connection structure can be stably ensured.

[0040] [Details of Embodiments of the Present Disclosure] Next, an embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0041] <One embodiment of the present disclosure> (1) Connecting power cable and cable connection structure The schematic configurations of a connecting power cable 10 and a cable connection structure (cable connection portion) 20 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3.

[0042] In FIGS. 2 and 3, the configuration of the lower half of the cable connection structure 20 is omitted. In FIGS. 2 and 3, the stripped power cable 100 is shown from the side. In FIGS. 2 and 3, some hatching is omitted.

[0043] As shown in FIG. 2, the connecting power cable 10 of the present embodiment has, for example, a plurality of power cables 100 and at least one cable connection structure 20.

[0044] Hereinafter, the "axial direction" of the power cable 100 refers to the direction along the central axis of the power cable 100, and can be rephrased as the longitudinal direction of the power cable 100. The "radial direction" of the power cable 100 refers to the direction perpendicular to the axial direction of the power cable 100 or the like, and can be rephrased as the short-side direction of the power cable 100 in some cases. The same terms as those for the power cable 100 are used for other cylindrical members constituting the cable connection structure 20.

[0045] (First power cable and second power cable) As shown in FIG. 1, the power cable 100 is configured as a solid insulation cable, which is a high-voltage power transmission cable on land or underground. The power cable 100 is configured, for example, as a CV cable (also referred to as a cross-linked polyethylene insulated vinyl chloride sheath cable, or XLPE cable).

[0046] Specifically, the power cable 100 has, for example, a conductor 110, an inner semi-conductive layer 120 of the cable, an insulation layer 130 of the cable, an outer semi-conductive layer 140 of the cable, a water absorption layer (not shown), a metal shielding layer 150 of the cable, and a cable sheath 160, in this order from a region near the central axis of the conductor 110 toward the outer periphery. The insulation layer 130 of the cable contains a polyolefin such as polyethylene. The polyolefin may be cross-linked. The metal shielding layer 150 of the cable is, for example, a metal covering or a winding layer of copper wires or copper tapes.

[0047] The conductor 110 has, for example, a plurality of conductor strands (not shown by reference numerals). The conductor strands contain, for example, at least one of copper and aluminum.

[0048] As shown in FIG. 2, the power cable 100 is stripped step by step from the axial tip of the conductor 110 in the opposite direction (so-called "step stripping"). That is, the conductor 110, the inner semi-conductive layer 120 of the cable, the insulation layer 130 of the cable, the outer semi-conductive layer 140 of the cable, the metal shielding layer 150 of the cable, and the cable sheath 160 are exposed in this order from the axial tip of the conductor 110 in the opposite direction. Hereinafter, each of the stripped parts may be referred to as an "exposed part". With such a configuration, the power cables 100 can be connected in order from a region near the central axis toward the outer periphery.

[0049] As shown in FIG. 2, a plurality of power cables 100 are provided. Among the plurality of power cables 100, a pair of power cables 100 are butted against each other with the axes of their respective conductors 110 aligned. Hereinafter, one of the pair of power cables 100 may be referred to as the "first power cable 100a", and the other power cable 100 may be referred to as the "second power cable 100b".

[0050] (Cable connection structure) As shown in FIG. 2, the cable connection structure 20 is configured to connect a pair of power cables 100, for example, as a so-called insulation connection part in three-phase alternating current. Specifically, the cable connection structure 20 includes, for example, the pair of power cables 100 described above, a sleeve (conductor connection pipe) 200, an insulation unit (insulation cylinder, rubber connection cylinder, rubber unit) 300, a spacer 500, and a protection part 400.

[0051] (Sleeve) The sleeve 200 is configured as, for example, a cylindrical metal pipe, connects the conductors 110 of the pair of power cables 100, and is provided so as to surround the respective tips of the pair of conductors 110. The cylindrical sleeve 200 may have a partition wall (not shown in the figure) at the center of the hollow part.

[0052] On the outside of the sleeve 200, for example, a semiconductive tape layer (not shown) may be provided so as to fill the step between the outer circumferences of the pair of cable insulation layers 130 and the outer circumference of the sleeve 200. Further, a sleeve cover (not shown) may be provided so as to surround the outer circumference of the sleeve 200 and lock the respective ends of the pair of cable insulation layers 130. By these means, uneven surface pressure of the insulation unit 300 described later can be suppressed.

[0053] (Insulation unit) The insulation unit 300 is configured as, for example, an insulating cylindrical member, and is provided so as to cover the outer circumference of the region including the sleeve 200.

[0054] The insulating unit 300 is configured, for example, as a so-called normal-temperature shrinkable type or a factory-expanded diameter type. That is, the insulating unit 300 has an integrally molded elastic material and is elastically shrunk at normal temperature to adhere to the connection portion of the power cable 100.

[0055] The insulating unit 300 is configured to relax the electric field around the sleeve 200 while ensuring the insulation around the sleeve 200. Specifically, the insulating unit 300 has, for example, an internal semiconductive layer 320 of the insulating unit, an insulating layer 340 of the insulating unit, and an external semiconductive layer 380 of the insulating unit.

[0056] The internal semiconductive layer 320 of the insulating unit is configured in a cylindrical shape so as to cover the outer circumference of the sleeve 200. The internal semiconductive layer 320 of the insulating unit contains, for example, a semiconductive rubber. The internal semiconductive layer 320 of the insulating unit is at the same electric potential as the sleeve 200.

[0057] The insulating layer 340 of the insulating unit is provided so as to cover the outer circumferences of the internal semiconductive layer 320 of the insulating unit, a part of the first power cable 100a, and a part of the second power cable 100b. The insulating layer 340 of the insulating unit contains, for example, an insulating rubber.

[0058] The external semiconductive layer 380 of the insulating unit is provided in the region outside the insulating unit 300 and is provided so as to cover the outer circumferences of the insulating layer 340 of the insulating unit, a part of the first power cable 100a, and a part of the second power cable 100b. The external semiconductive layer 380 of the insulating unit contains a semiconductive rubber.

[0059] The external semiconductive layer 380 of the insulation unit has, for example, a stress cone portion 360. The stress cone portion 360 is provided at a position close to each of the axial ends of the insulation unit insulating layer 340. The stress cone portion 360 has an inner peripheral surface in the shape of a cone whose diameter expands toward the center in the axial direction of the insulation unit insulating layer 340. A part of the inner peripheral surface of the stress cone portion 360 is in contact with the exposed portion of the cable external semiconductive layer 140 of the power cable 100 with the outer sheath peeled off.

[0060] With such a configuration of the insulation unit 300, it is possible to electrically shield the periphery of the sleeve 200 and relax the electric field at the tip of the cable external semiconductive layer 140.

[0061] Here, in the present embodiment, the external semiconductive layer 380 of the insulation unit has at least one separation portion SP separated in the axial direction of the first power cable 100a and the second power cable 100b. Here, one separation portion SP is provided, for example, at a position close to the second power cable 100b. The separation portion SP separates, for example, the external semiconductive layer 380 of the insulation unit in the region close to the first power cable 100a and the external semiconductive layer 380 of the insulation unit in the region close to the second power cable 100b. Thereby, the insulation unit 300 can be electrically separated between the shielding of the first power cable 100a and the shielding of the second power cable 100b.

[0062] In the present embodiment, a first end face 390a orthogonal to the central axis of the insulation unit 300 is provided at the first end in the axial direction of the insulation unit 300. On the other hand, a second end face 390b orthogonal to the central axis of the insulation unit 300 is provided at the second end opposite to the first end in the axial direction of the insulation unit 300. Such perpendicular first end face 390a and second end face 390b of the insulation unit 300 are used, for example, as support surfaces when inserting an enlarged-diameter pipe for passing the power cable 100 into the hollow portion of the insulation unit 300 by hydraulic pressure.

[0063] (Spacer) The spacer 500 is provided so as to surround the outer circumference of each of a pair of power cables 100 and to contact the axial end of the insulating unit 300. For example, the spacer 500 gradually decreases in diameter in a direction away from the axial end of the insulating unit 300 along the conductor 110. Thereby, a gentle slope (inclined surface, conical surface) inclined gently from the outer circumference of the insulating unit 300 toward the outer circumference of the power cable 100 can be formed.

[0064] Hereinafter, the spacer 500 surrounding the outer circumference of the first power cable 100a is also referred to as "first spacer 500a", and the spacer 500 surrounding the outer circumference of the second power cable 100b is also referred to as "second spacer 500b".

[0065] In the present embodiment, the spacer 500 is constituted by, for example, a molded body. Thereby, a slope can be easily formed in the vicinity of the axial end of the insulating unit 300.

[0066] In the present embodiment, the spacer 500 contains, for example, a thermoplastic resin. Thereby, the spacer 500 can be easily injection-molded. Examples of the thermoplastic resin include nylon, polycarbonate, and phenolic resin. In particular, nylon satisfies the above-mentioned requirements and facilitates free molding.

[0067] In the present embodiment, the spacer 500 has, for example, a hollow structure. Thereby, sink marks of the resin during injection molding can be suppressed.

[0068] In the present embodiment, the spacer 500 is divided into a plurality of parts, for example, in a cross section including the central axis of the spacer 500. Thereby, the divided spacer 500 can be fitted from the outside of the power cable 100.

[0069] In this embodiment, the spacer 500 has, for example, ribs 580. The ribs 580 are, for example, configured in a plate shape and extend from the inner peripheral surface of the spacer 500 toward the central axis. Thereby, even if stress (shrinking force, tightening force) by the protection part 400 is applied to the spacer 500 in the protection part forming step S40 described later, the shape of the spacer 500 can be maintained by the ribs 580.

[0070] (Semiconductive tape layer) The semiconductive tape layer 480 is configured, for example, by winding a semiconductive tape so as to cover the outer periphery of the exposed part of the cable outer semiconductive layer 140 of the power cable 100 between the spacer 500 and the power cable 100. The semiconductive tape layer 480 is connected, for example, to the end of the stress cone part 360 of the insulating unit 300. Thereby, the cable outer semiconductive layer 140, the semiconductive tape layer 480, and the stress cone part 360 can be electrically connected. Also, the semiconductive tape layer 480 can function as a cushion layer between the first shielding layer 410 or the second shielding layer 420 made of a copper mesh tape described later and the cable outer semiconductive layer 140. Furthermore, by making the outer diameter of the semiconductive tape layer 480 coincide with the inner diameter of the rib 580 extending from the inner peripheral surface of the spacer 500 toward the central axis side, the semiconductive tape layer 480 can function as a pedestal of the spacer 500.

[0071] (Protection part) The protection part 400 is configured to cover the outer periphery of the insulating unit 300, the spacer 500, a part of the first power cable 100a, and a part of the second power cable 100b. Details of the protection part 400 of this embodiment will be described later.

[0072] (2) Protection part Next, with reference to FIGS. 2 and 3, the protection part 400 will be described.

[0073] As shown in FIGS. 2 and 3, the protection part 400 has, for example, a first shielding layer 410 (thick dotted line), a second shielding layer 420 (thick dotted line), an insulating intermediate layer 430, an insulating tape layer 440, and a water shielding layer 450.

[0074] (First shielding layer) The first shielding layer 410 is connected to, for example, the cable metal shielding layer 150 of the first power cable 100a, and is configured to electrically shield a part of the first power cable 100a and the insulating unit 300. The first shielding layer 410 is composed of, for example, a copper mesh tape.

[0075] Specifically, as shown in FIG. 2, the first shielding layer 410 is provided so as to continuously cover, for example, the outer periphery of the exposed part of the cable outer semiconductive layer 140 of the first power cable 100a, the outer periphery of the first spacer 500a, and the outer periphery of the insulating unit outer semiconductive layer 380 of the insulating unit 300. The first shielding layer 410 can surely connect the cable metal shielding layer 150 of the first power cable 100a and the insulating unit outer semiconductive layer 380 of the insulating unit 300.

[0076] (Second shielding layer) The second shielding layer 420 is connected to, for example, the cable metal shielding layer 150 of the second power cable 100b, and is configured to electrically shield a part of the second power cable 100b. The second shielding layer 420 is composed of, for example, a copper mesh tape, similar to the first shielding layer 410.

[0077] Specifically, as shown in FIGS. 2 and 3, the second shielding layer 420 is provided so as to cover the outer periphery of the exposed part of the cable outer semiconductive layer 140 of the second power cable 100b between the second spacer 500b and the second power cable 100b, and is connected to the stress cone part 360 of the insulating unit 300. The second shielding layer 420 is provided, for example, on the outer periphery of the semiconductive tape layer 480. The second shielding layer 420 can surely connect the cable metal shielding layer 150 of the second power cable 100b and the stress cone part 360 of the insulating unit 300.

[0078] In this embodiment, the second shielding layer 420 is spaced apart from the first shielding layer 410 in the axial direction of the conductor 110 by sandwiching a predetermined shielding separation portion (not shown in the figure) therebetween. The "shielding separation portion" mentioned here means an area (space) where neither shielding layer is provided. The shielding separation portion between the first shielding layer 410 and the second shielding layer 420 overlaps, for example, with the separation portion SP of the external semiconductive layer 380 of the insulation unit 300 outside the insulation unit. Thereby, the first shielding layer 410 and the second shielding layer 420 can be electrically insulated (isolated).

[0079] Between the first shielding layer 410 and the second shielding layer 420, the length (separation distance) of the shielding separation portion in the axial direction of the conductor 110 is, for example, 150 mm or more. Thereby, based on the empirical rule, even if an air layer exists on the shielding separation portion, breakdown between the shields can be suppressed.

[0080] With the above-described shielding structure provided, outside the insulation unit 300 in the axial direction, the cable metal shielding layer 150 of the first power cable 100a and the cable metal shielding layer 150 of the second power cable 100b are each connected to the grounding system by a grounding wire (not shown). In the case of cross-bond grounding, each of the shielding of the first power cable 100a and the shielding of the second power cable 100b is connected to the shielding of the other phase in the adjacent section.

[0081] (Insulation intermediate layer) The insulation intermediate layer 430 is provided to ensure insulation between the first shielding layer 410 and the second shielding layer 420 and the water shielding layer 450 described later.

[0082] Specifically, the insulation intermediate layer 430 contains, for example, an insulating resin. The insulation intermediate layer 430 is provided so as to continuously cover, for example, the outer periphery of the first shielding layer 410, the outer periphery of the insulation unit 300 exposed in the shielding separation portion, and the outer periphery of the second shielding layer 420.

[0083] In this embodiment, the insulating intermediate layer 430 is constituted by, for example, a room temperature shrinkable tube that elastically shrinks at room temperature (for example, 22°C). Thereby, it is possible to stably ensure the insulation property (insulation property between the conductor and the ground) between the first shielding layer 410 and the second shielding layer 420 and the water shielding layer 450 described later, and the insulation property (insulation property between the shields) between the first shielding layer 410 and the second shielding layer 420.

[0084] In this embodiment, as the insulating resin constituting the room temperature shrinkable tube of the insulating intermediate layer 430, for example, it contains ethylene propylene rubber or silicone rubber. Thereby, the insulation property and heat resistance of the insulating intermediate layer 430 can be improved.

[0085] In this embodiment, by elastically shrinking the room temperature shrinkable tube as the insulating intermediate layer 430, the insulating intermediate layer 430 can be uniformly provided on the outer peripheries of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300.

[0086] Here, when an insulating tape is spirally wound as the insulating intermediate layer, a step is inevitably generated at the portion where the insulating tapes are spirally overlapped. Therefore, the thickness of the insulating intermediate layer in the cross section orthogonal to the central axis of the conductor becomes non-uniform in the circumferential direction of the insulating intermediate layer. Furthermore, in the region where the insulating intermediate layer overlaps the shielding separation portion between the shielding layers, the thickness of the insulating intermediate layer becomes non-uniform along the axial direction of the conductor. When the thickness of the insulating intermediate layer becomes non-uniform in this way, there is a possibility that the insulation property at the portion where the insulating tape is relatively thin may decrease.

[0087] In contrast, in the present embodiment, by using a room-temperature shrinkable tube as the insulating intermediate layer 430, the thickness of the insulating intermediate layer 430 in a cross-section orthogonal to the central axis of the conductor 110 is, for example, uniform over the entire circumference of the insulating intermediate layer 430. In other words, no unnecessary step (for example, a step greater than the thickness) of the insulating intermediate layer 430 occurs on the outer circumferences of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300, respectively. Thereby, compared with the case where an insulating tape is spirally wound, the insulation property (insulation property between the conductor and the ground) between the first shielding layer 410 and the second shielding layer 420 and the water shielding layer 450 described later can be stably ensured over the entire circumference of the insulating intermediate layer 430.

[0088] Furthermore, in the present embodiment, by using a room-temperature shrinkable tube as the insulating intermediate layer 430, the thickness of the insulating intermediate layer 430 in the region overlapping the shielding separation portion between the first shielding layer 410 and the second shielding layer 420 is, for example, uniform along the axial direction of the conductor 110. In other words, in the shielding separation portion, no unnecessary step (for example, a step greater than the thickness) of the insulating intermediate layer 430 occurs. Thereby, compared with the case where an insulating tape is spirally wound, the insulation property (insulation property between the shields) between the first shielding layer 410 and the second shielding layer 420 can be stably ensured.

[0089] The above-mentioned "uniform thickness" means that the thickness error is 5% or less with respect to the average value of the thickness.

[0090] In this embodiment, the insulating intermediate layer 430 has a thickness that can withstand an impulse voltage of 40 kV or more, for example, in a state where the diameter of the insulating intermediate layer 430 is expanded outside the insulating unit 300. Specifically, when the power cable 100 is of the 66 kV class, the insulating intermediate layer 430 has a thickness that can withstand an impulse voltage of 40 kV three times in the expanded state. Alternatively, when the power cable 100 is of the 154 kV class, the insulating intermediate layer 430 has a thickness that can withstand an impulse voltage of 50 kV three times in the expanded state. The waveform of the impulse voltage shall be the waveform of the standard lightning impulse voltage defined in JEC-0203:2022. However, as described in JEC-3408:2015, a margin is allowed within the range where the wavefront length is 0.5 μs or more and 5 μs or less. Since the insulating intermediate layer 430 has a thickness that can withstand the above-described impulse voltage, even if an impulse voltage occurs in at least one of the between-earth and between-shielding, the insulation property of the insulating intermediate layer 430 can be maintained. As a result, the insulation breakdown of the cable connection structure 20 can be stably suppressed.

[0091] Specifically, for example, when the resin constituting the insulating intermediate layer 430 is ethylene propylene rubber or silicone rubber, the thickness of the insulating intermediate layer 430 is 0.5 mm or more in the above-described expanded state, or may be 1.0 mm or more, or may be 1.5 mm or more. Thereby, the insulating intermediate layer 430 can withstand the above-described impulse voltage.

[0092] In this embodiment, by elastically contracting the heat-shrinkable tube as the insulating intermediate layer 430, the insulating intermediate layer 430 is in close contact with the outer circumferences of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300, respectively. In other words, no air layer is formed between the inner circumference of the insulating intermediate layer 430 and the outer circumferences of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300, respectively. Thereby, the insulation property between the earth and the insulation property between the shieldings can be stably ensured.

[0093] In this embodiment, the insulating intermediate layer 430 may have, for example, at least two normal-temperature shrinkable tubes that are axially separable from the conductor 110. Thereby, the shrinkage operation of the normal-temperature shrinkable tube on the insulating unit 300 or the like can be easily performed.

[0094] Specifically, the insulating intermediate layer 430 has, for example, a first normal-temperature shrinkable tube 431 and a second normal-temperature shrinkable tube 432. The first normal-temperature shrinkable tube 431 covers, for example, the outer periphery of the first shielding layer 410. On the other hand, the second normal-temperature shrinkable tube 432 covers, for example, the outer periphery of the insulating unit 300 exposed at the shielding separation part between the first shielding layer 410 and the second shielding layer 420 and the outer periphery of the second shielding layer 420 (the outer periphery of the second spacer 500b).

[0095] The first normal-temperature shrinkable tube 431 and the second normal-temperature shrinkable tube 432 are overlapped with each other at positions excluding the shielding separation part between the first shielding layer 410 and the second shielding layer 420. Thereby, the generation of a step due to the overlap of the first normal-temperature shrinkable tube 431 and the second normal-temperature shrinkable tube 432 on the shielding separation part can be suppressed. As a result, even if the insulating intermediate layer 430 is configured to be separable, the insulation between the shields can be stably ensured.

[0096] (Insulating tape layer) An insulating tape layer 440 may be provided to assist the insulating intermediate layer 430. Specifically, for example, the insulating tape layer 440 may be provided so as to cover the region from the outer periphery near the end of the insulating intermediate layer 430 in the axial direction of the conductor 110 to the connection part between each cable metal shielding layer 150 and the ground wire. The insulating tape layer 440 is composed of, for example, a self-fusing tape. Thereby, the insulation against the outside of the cable connection structure 20 can be ensured.

[0097] (Waterproof layer) The waterproof layer 450 is configured to ensure the waterproof property of the cable connection structure 20, for example.

[0098] Specifically, the water barrier layer 450 includes, for example, a water barrier metal sheet. The water barrier layer 450 is provided, for example, so as to cover the outer periphery of the insulating intermediate layer 430. The water barrier layer 450 may also cover a region including the outer periphery of the above-described insulating tape layer 440. By covering the entire cable connection structure 20 with the water barrier layer 450 in this way, it is possible to suppress damage to the cable connection structure 20 while ensuring the water barrier property of the cable connection structure 20, and to ensure the shape stability of the cable connection structure 20.

[0099] In the present embodiment, the water barrier layer 450 is configured as, for example, a so-called water barrier heat shrinkable tube. Specifically, the water barrier layer 450 has, for example, a (tubular) metal sheet, a first resin layer covering the inner periphery of the metal sheet, and a second resin sheet covering the outer periphery of the metal sheet. The first resin layer and the second resin layer contain, for example, a resin that shrinks upon heating. Examples of the resin constituting the first resin layer and the second resin layer include crosslinked polyolefin.

[0100] As described above, since the water barrier layer 450 is shrunk as a heat shrinkable tube, the water barrier layer 450 is in close contact with the outer periphery of the insulating intermediate layer 430. A heat shrinkage force is applied from the water barrier layer 450 toward the insulating intermediate layer 430 in the thickness direction (radial direction). For this reason, the metal sheet of the water barrier layer 450 is close to the first shielding layer 410 and the second shielding layer 420 in the thickness direction. Even with such a configuration, the normal temperature shrinkable tube as the above-described insulating intermediate layer 430 is uniformly interposed between the metal sheet of the water barrier layer 450 and the first shielding layer 410 and the second shielding layer 420, so that the insulation between the ground and the insulation between the shields can be stably ensured.

[0101] In the present embodiment, the heat shrinkable tube as the water barrier layer 450 may be formed into a tube shape, for example, by joining the long sides of a sheet having a first resin layer, a metal sheet, and a second resin layer with a fastener. Thereby, the water barrier layer 450 can be easily attached to the outside of the pair of power cables 100 and the insulating unit 300.

[0102] (3) Manufacturing Method of Cable Connection Structure (Manufacturing Method of Connected Power Cable, Cable Connection Method) Next, with reference to FIGS. 1 to 3, the manufacturing method of the cable connection structure 20 according to the present embodiment will be described.

[0103] The manufacturing method of the cable connection structure 20 of the present embodiment has, for example, a preparation step S10, a conductor connection step S20, an insulating unit arrangement step S30, and a protection part formation step S40.

[0104] (S10: Preparation Step) First, members of each layer of a pair of power cables 100, sleeves 200, insulating units 300, spacers 500, and protection parts 400 that constitute the cable connection structure 20 are prepared.

[0105] For example, in a factory in advance, with the insulating unit 300 supported by either the vertical first end face 390a or the second end face 390b of the insulating unit 300, an expanding pipe is inserted into the hollow part of the insulating unit 300 by hydraulic pressure. Thereby, the insulating unit 300 is expanded.

[0106] Furthermore, for example, in a factory in advance, a room-temperature shrinkable tube as the insulating intermediate layer 430 is expanded by a cylindrical inner core in which inner core ribbons are spirally combined.

[0107] Next, for example, at the cable laying site of the power cable 100, the two ends of the pair of power cables 100 are gradually peeled off axially. Thereby, the conductor 110, the cable insulating layer 130, the cable outer semiconductive layer 140, and the cable sheath 160 are exposed in this order from the tip of the power cable 100.

[0108] After preparing each member that constitutes the cable connection structure 20, the power cable 100 is passed through each of the insulating unit 300 and the room-temperature shrinkable tube as the insulating intermediate layer 430, and the insulating unit 300 and the room-temperature shrinkable tube as the insulating intermediate layer 430 are left at predetermined positions of the power cable 100.

[0109] (S20: Conductor Connection Step) When the preparation step S10 is completed, a pair of power cables 100 are butted against each other with the axes of their respective conductors 110 aligned within the sleeve 200. After butting the pair of power cables 100, the conductors 110 of the pair of power cables 100 are connected by compressing the sleeve 200.

[0110] Note that a semiconductive tape layer (not shown) may be provided so as to fill the step between the outer circumferences of the pair of cable insulating layers 130 and the outer circumference of the sleeve 200. Further, a sleeve cover may be provided outside thereof.

[0111] (S30: Insulating Unit Arrangement Step) When the conductor connection step S20 is completed, an insulating unit 300 for ensuring the insulation around the sleeve 200 is provided so as to cover the outer circumference of the region including the sleeve 200. Specifically, the insulating unit 300 expanded by an expanding pipe is moved to a position overlapping the sleeve 200. After the insulating unit 300 is arranged at a predetermined position, the expanding pipe is gradually pulled out from the insulating unit 300, and the insulating unit 300 is gradually reduced in diameter in the axial direction. In this way, the insulating unit 300 is arranged so as to cover the outer circumference of the sleeve 200 and a part of the outer circumferences of each of the pair of power cables 100.

[0112] (S40: Protection Part Formation Step) When the insulating unit arrangement step S30 is completed, a protection part 400 is formed so as to cover the insulating unit 300, a part of the first power cable 100a, and a part of the second power cable 100b.

[0113] The protection part formation step S40 has, for example, a first shielding layer formation step S42, a second shielding layer formation step S44, an insulating intermediate layer formation step S46, and a water shielding layer formation step S48.

[0114] (S42: First Shielding Layer Formation Step) First, on the outside of the first axial end of the insulating unit 300, a semiconductive tape layer 480 is formed by winding a semiconductive tape so as to cover the outer periphery of the exposed portion of the cable outer semiconductive layer 140 of the first power cable 100a.

[0115] After forming the semiconductive tape layer 480, a first spacer 500a that gradually decreases in diameter along the axial direction is arranged to surround the outer periphery of the first power cable 100a (the outer periphery of the semiconductive tape layer 480) and to contact the first axial end of the insulating unit 300.

[0116] After arranging the first spacer 500a, a first shielding layer 410 is formed so as to electrically shield a part of the first power cable 100a and the insulating unit 300.

[0117] After forming the first shielding layer 410, the cable metal shielding layer 150 of the first power cable 100a is connected to the grounding system by a ground wire.

[0118] (S44: Second shielding layer forming step) On the other hand, on the outside of the second axial end of the insulating unit 300, a semiconductive tape layer 480 is formed by winding a semiconductive tape so as to cover the outer periphery of the exposed portion of the cable outer semiconductive layer 140 of the second power cable 100b.

[0119] After forming the semiconductive tape layer 480, a second shielding layer 420 is formed on the outer periphery of the semiconductive tape layer 480 so as to be separated from the first shielding layer 410 by a predetermined shielding separation portion in the axial direction of the conductor 110 and to electrically shield a part of the second power cable 100b. At this time, the second shielding layer 420 is connected to the stress cone portion 360 of the insulating unit 300.

[0120] After forming the second shielding layer 420, a second spacer 500b that gradually decreases in diameter along the axial direction is arranged to surround the outer periphery of the second power cable 100b (the outer periphery of the second shielding layer 420) and to contact the second axial end of the insulating unit 300.

[0121] After arranging the second spacer 500b, connect the cable metal shielding layer 150 of the second power cable 100b to the grounding system by a grounding wire.

[0122] Note that the second shielding layer forming step S44 may be performed prior to the first shielding layer forming step S42.

[0123] (S46: Insulating intermediate layer forming step) After the first shielding layer forming step S42 and the second shielding layer forming step S44 are completed, an insulating intermediate layer 430 containing an insulating resin is provided so as to continuously cover the outer periphery of the first shielding layer 410, the outer periphery of the insulating unit 300 exposed at the shielding separation portion, and the outer periphery of the second shielding layer 420.

[0124] At this time, in the present embodiment, the insulating intermediate layer 430 is constituted by a normal temperature shrinkable tube that elastically shrinks at normal temperature. Specifically, a normal temperature shrinkable tube as the insulating intermediate layer 430 whose diameter has been expanded in advance by an inner core is moved to a position overlapping the insulating unit 300. After moving the normal temperature shrinkable tube to a predetermined position, the inner core ribbon is pulled out from the inside of the normal temperature shrinkable tube, whereby the normal temperature shrinkable tube is gradually shrunk along the axial direction of the conductor 110. Thereby, the insulating intermediate layer 430 is uniformly formed on the outer peripheries of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300.

[0125] At this time, in the present embodiment, the insulating intermediate layer 430 may be formed by at least two normal temperature shrinkable tubes that are separable in the axial direction of the conductor 110.

[0126] After forming the insulating intermediate layer 430, an insulating tape layer 440 may be provided so as to cover the region from the outer periphery near the end of the insulating intermediate layer 430 in the axial direction of the conductor 110 to the connection portion between each cable metal shielding layer 150 and the grounding wire.

[0127] (S48: Water shielding layer forming step) After the insulating intermediate layer forming step S46 is completed, a water shielding layer 450 containing a water shielding metal sheet is formed so as to cover the outer periphery of the insulating intermediate layer 430.

[0128] Specifically, a sheet that becomes a water-blocking heat-shrinkable tube is wound around the outer periphery of the region including the insulating intermediate layer 430, and the long sides of the sheet are joined by a fastener. Next, with the water-blocking heat-shrinkable tube arranged at a predetermined position as described above, the water-blocking heat-shrinkable tube is shrunk by heating. Thereby, a water-blocking layer 450 is formed so as to cover the outer periphery of the insulating intermediate layer 430.

[0129] Thus, the cable connection structure 20 and the connecting power cable 10 of the present embodiment are manufactured.

[0130] (4) Summary of the present embodiment According to the present embodiment, one or more of the following effects are achieved.

[0131] (a) In the present embodiment, an insulating intermediate layer 430 is provided between the first shielding layer 410 and the second shielding layer 420 and the water-blocking layer 450. The insulating intermediate layer 430 is composed of a normal-temperature shrinkable tube that elastically shrinks at normal temperature.

[0132] Since the insulating intermediate layer 430 is composed of a normal-temperature shrinkable tube, even when the first shielding layer 410 and the second shielding layer 420 and the water-blocking layer 450 are in a state of being close to each other in the thickness direction, the insulating intermediate layer 430 can be uniformly provided over the entire outer periphery of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300. Thereby, a decrease in the insulation property (insulation property between the ground) between the first shielding layer 410 and the second shielding layer 420 and the water-blocking layer 450 can be suppressed.

[0133] Furthermore, since the insulating intermediate layer 430 is composed of a normal-temperature shrinkable tube, the insulating intermediate layer 430 can continuously cover the shielding separation portion between the first shielding layer 410 and the second shielding layer 420 without interruption. Thereby, a decrease in the insulation property (insulation property between the shields) between the first shielding layer 410 and the second shielding layer 420 through the metal sheet of the water-blocking layer 450 can be suppressed.

[0134] Thus, according to this embodiment, in the cable connection structure 20, it is possible to stably ensure the insulation between the cable and the ground and the insulation between the shields.

[0135] (b) In this embodiment, by using a normal-temperature shrinkable tube as the insulating intermediate layer 430, the thickness of the insulating intermediate layer 430 can be made uniform and the insulating intermediate layer 430 can be easily arranged over the entire outer circumferences of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300. As a result, in the process of forming the insulating intermediate layer 430, excessive skills of the operator can be dispensed with. Consequently, the manufacturing process of the cable connection structure 20 can be simplified and facilitated.

[0136] (c) In this embodiment, by elastically shrinking the normal-temperature shrinkable tube as the insulating intermediate layer 430, it is possible to suppress the formation of an air layer with low insulation between the inner circumference of the insulating intermediate layer 430 and the respective outer circumferences of the first shielding layer 410, the second shielding layer 420, and the insulating unit 300. Also from this perspective, the insulation between the cable and the ground and the insulation between the shields can be stably ensured.

[0137] (d) In this embodiment, by using a normal-temperature shrinkable tube as the insulating intermediate layer 430, a resin with good heat resistance can be applied as the resin constituting the insulating intermediate layer 430. Thereby, even when the heat shrinkable tube as the water shielding layer 450 is shrunk by heat, deformation of the insulating intermediate layer 430 caused by heating can be suppressed. By suppressing the deformation of the insulating intermediate layer 430, the occurrence of a portion with a thin thickness of the insulating intermediate layer 430 can be suppressed. Also from this perspective, the insulation between the cable and the ground and the insulation between the shields can be stably ensured.

[0138] (e) In this embodiment, by using a room-temperature shrinkable tube as the insulating intermediate layer 430, even if the insulating unit 300 in the cable connection structure expands in volume when the cable connection structure generates heat during operation, the insulating intermediate layer 430 can follow the fluctuations of the insulating unit 300. Thereby, a long-term decrease in the surface pressure of the insulating intermediate layer 430 can be suppressed. Also from this perspective, the insulation between the conductor and the ground and the insulation between the shields can be stably ensured.

[0139] <Other embodiments of the present disclosure> As described above, the embodiments of the present disclosure have been specifically described. However, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

[0140] In the above-described embodiment, one cable connection structure 20 included in the connecting power cable 10 has been described. However, the connecting power cable 10 may have a plurality of cable connection structures 20.

[0141] In the above-described embodiment, the case where the insulating intermediate layer 430 has at least two separable room-temperature shrinkable tubes has been described. However, the present disclosure is not limited to this case. The insulating intermediate layer 430 may not be separated. That is, the insulating intermediate layer 430 may have, for example, one room-temperature shrinkable tube that covers the entire outer periphery of the insulating unit 300 in the axial direction of the conductor 110. Thereby, the entire outer periphery of the insulating unit 300 can be evenly covered by one room-temperature shrinkable tube without causing a step in the room-temperature shrinkable tube on the outer periphery of the insulating unit 300. As a result, the insulation of the cable connection structure 20 can be stably ensured.

[0142] <Supplementary Note> Hereinafter, aspects of the present disclosure will be appended.

[0143] (Supplementary Note 1) A first power cable and a second power cable each having a conductor, A cylindrical sleeve that connects the conductor of the first power cable and the conductor of the second power cable, An insulating unit provided to cover the outer periphery of the region including the sleeve, and maintaining the insulation around the sleeve, A protective part that covers the outer periphery of the insulating unit, a part of the first power cable, and a part of the second power cable, Comprising, The protective part is, A first shielding layer that electrically shields a part of the first power cable and the insulating unit, A second shielding layer that is separated from the first shielding layer by a predetermined shielding separation part in the axial direction of the conductor, and electrically shields a part of the second power cable, An insulating intermediate layer containing an insulating resin, continuously covering the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation part, and the outer periphery of the second shielding layer, A water shielding layer containing a water shielding metal sheet, covering the outer periphery of the insulating intermediate layer, Having, The insulating intermediate layer is composed of a normal temperature shrinkable tube that elastically shrinks at normal temperature Cable connection structure.

[0144] (Appendix 2) The water shielding layer has a first resin layer covering the inner periphery of the metal sheet and a second resin layer covering the outer periphery of the metal sheet, The first resin layer and the second resin layer contain a resin that shrinks by heating The cable connection structure according to Appendix 1.

[0145] (Appendix 3) The thickness of the insulating intermediate layer in a cross section perpendicular to the central axis of the conductor is uniform over the entire circumference of the insulating intermediate layer The cable connection structure according to Appendix 1 or Appendix 2.

[0146] (Appendix 4) The thickness of the insulating intermediate layer in the region overlapping the shielding separation part is uniform along the axial direction of the conductor The cable connection structure according to any one of Appendices 1 to 3.

[0147] (Appendix 5) The insulating intermediate layer has a thickness capable of withstanding an impulse voltage of 40 kV or more in a state where the insulating intermediate layer is expanded in diameter outside the insulating unit. The cable connection structure according to any one of Appendices 1 to 4.

[0148] (Appendix 6) The insulating intermediate layer contains ethylene propylene rubber or silicone rubber. The cable connection structure according to any one of Appendices 1 to 5.

[0149] (Appendix 7) The thickness of the insulating intermediate layer is 0.5 mm or more in a state where the insulating intermediate layer is expanded in diameter outside the insulating unit. The cable connection structure according to Appendix 6.

[0150] (Appendix 8) The insulating intermediate layer has at least two normal temperature shrinkable tubes separable in the axial direction of the conductor. The cable connection structure according to any one of Appendices 1 to 7.

[0151] (Appendix 9) The insulating intermediate layer is a first normal temperature shrinkable tube covering the outer periphery of the first shielding layer, a second normal temperature shrinkable tube covering the outer periphery of the second shielding layer, and includes the first normal temperature shrinkable tube and the second normal temperature shrinkable tube are overlapped with each other at a position excluding the shielding separation part. The cable connection structure according to Appendix 8.

[0152] (Appendix 10) The insulating intermediate layer has one normal temperature shrinkable tube covering the entire outer periphery of the insulating unit in the axial direction of the conductor. The cable connection structure according to any one of Appendices 1 to 7.

[0153] (Appendix 11) Having at least one cable connection structure according to any one of Appendices 1 to 10 Connected power cable.

[0154] (Appendix 12) The step of preparing a first power cable and a second power cable each having a conductor, The step of connecting the conductor of the first power cable and the conductor of the second power cable with a cylindrical sleeve, The step of arranging an insulating unit for maintaining the insulation around the sleeve so as to cover the outer periphery of the region including the sleeve, The step of providing a protective part so as to cover the outer periphery of the insulating unit, a part of the first power cable, and a part of the second power cable, Comprising The step of providing the protective part The step of providing a first shielding layer so as to electrically shield a part of the first power cable and the insulating unit, The step of providing a second shielding layer so as to be separated from the first shielding layer by a predetermined shielding separation part in the axial direction of the conductor and electrically shield a part of the second power cable, The step of providing an insulating intermediate layer containing an insulating resin so as to continuously cover the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation part, and the outer periphery of the second shielding layer, The step of providing a water shielding layer containing a water shielding metal sheet so as to cover the outer periphery of the insulating intermediate layer, Having In the step of providing the insulating intermediate layer, The insulating intermediate layer is constituted by a normal temperature shrinkable tube that elastically shrinks at normal temperature Method for manufacturing a cable connection structure.

Description of reference numerals

[0155] 10 Connected power cable 20 Cable Connection Structure 100 Power Cable 100a First Power Cable 100b Second Power Cable 110 Conductor 120 Inner Semiconductor Layer of Cable 130 Insulation Layer of Cable 140 Outer Semiconductor Layer of Cable 150 Metal Shielding Layer of Cable 160 Cable Sheath 200 Sleeve 300 Insulation Unit 320 Inner Semiconductor Layer of Insulation Unit 340 Insulation Layer of Insulation Unit 360 Stress Cone Part 380 Outer Semiconductor Layer of Insulation Unit 390a First End Face 390b Second End Face 400 Protection Part 410 First Shielding Layer 420 Second Shielding Layer 430 Insulation Intermediate Layer 431 First Normal Temperature Shrinkable Tube 432 Second Normal Temperature Shrinkable Tube 440 Insulation Tape Layer 450 Water-Proof Layer 480 Semiconductor Tape Layer 500 Spacer 500a First Spacer 500b Second Spacer 580 Rib SP Separation Part

Claims

1. A first power cable and a second power cable each having a conductor, a cylindrical sleeve connecting the conductor of the first power cable and the conductor of the second power cable, an insulating unit provided to cover the outer periphery of the region including the sleeve and maintaining the insulation around the sleeve, a protective part covering the outer periphery of the insulating unit, a part of the first power cable, and a part of the second power cable, comprising: The protective part: a first shielding layer that electrically shields a part of the first power cable and the insulating unit, a second shielding layer spaced apart from the first shielding layer by a predetermined shielding separation part in the axial direction of the conductor and electrically shielding a part of the second power cable, an insulating intermediate layer containing an insulating resin and continuously covering the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation part, and the outer periphery of the second shielding layer, a water shielding layer containing a water shielding metal sheet and covering the outer periphery of the insulating intermediate layer, having: The insulating intermediate layer is constituted by a normal temperature shrinkable tube that elastically shrinks at normal temperature. A cable connection structure.

2. The water shielding layer has a first resin layer covering the inner periphery of the metal sheet and a second resin layer covering the outer periphery of the metal sheet, and the first resin layer and the second resin layer contain a resin that shrinks upon heating. The cable connection structure according to Claim 1.

3. The thickness of the insulating intermediate layer in a cross section perpendicular to the central axis of the conductor is uniform over the entire circumference of the insulating intermediate layer. The cable connection structure according to Claim 1 or Claim 2.

4. The thickness of the insulating intermediate layer in the region overlapping the shielding separation part is uniform along the axial direction of the conductor. The cable connection structure according to Claim 1 or Claim 2.

5. The insulating intermediate layer has a thickness capable of withstanding an impulse voltage of 40 kV or more in a state where the insulating intermediate layer is expanded in diameter outside the insulating unit. The cable connection structure according to Claim 1 or Claim 2.

6. The insulating intermediate layer has at least two normal temperature shrinkable tubes separable in the axial direction of the conductor. The cable connection structure according to Claim 1 or Claim 2.

7. The insulating intermediate layer has one normal temperature shrinkable tube covering the entire outer periphery of the insulating unit in the axial direction of the conductor. The cable connection structure according to Claim 1 or Claim 2.

8. A connecting power cable comprising at least one cable connection structure according to claim 1 or claim 2 connected power cable.

9. Preparing a first power cable and a second power cable each having a conductor; Connecting the conductor of the first power cable and the conductor of the second power cable with a cylindrical sleeve; Arranging an insulating unit for maintaining the insulation around the sleeve so as to cover the outer periphery of the region including the sleeve; Providing a protective part so as to cover the outer periphery of the insulating unit, a part of the first power cable, and a part of the second power cable; comprising The step of providing the protective part includes Providing a first shielding layer so as to electrically shield a part of the first power cable and the insulating unit; Providing a second shielding layer so as to be spaced apart from the first shielding layer with a predetermined shielding separation part interposed in the axial direction of the conductor and electrically shield a part of the second power cable; Providing an insulating intermediate layer containing an insulating resin so as to continuously cover the outer periphery of the first shielding layer, the outer periphery of the insulating unit exposed at the shielding separation part, and the outer periphery of the second shielding layer; Providing a water shielding layer containing a water shielding metal sheet so as to cover the outer periphery of the insulating intermediate layer; having In the step of providing the insulating intermediate layer, The insulating intermediate layer is constituted by a normal temperature shrinkable tube that elastically shrinks at normal temperature Method for manufacturing a cable connection structure.

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