JP7822243B2 - Intermediate connection unit for power cables and method for connecting power cables - Google Patents

Description

This disclosure relates to an intermediate connection unit for power cables and a method for connecting power cables.

Cable intermediate connection structures that connect the ends of power cables have been known for some time.

For example, Patent Document 1 describes an insulating cylinder with an expandable support cylinder, in which a cold-shrinkable insulating cylinder is supported by an expandable support cylinder. In the insulating cylinder with an expandable support cylinder of Patent Document 1, the expandable support cylinder is made up of multiple cylindrical cores stacked in inner and outer layers, and at least the cylindrical core on the side that comes into contact with the insulating cylinder is made up of a spiral core formed by spirally winding a string-like material.

As in Patent Document 1, in assembling a conventional cable middle joint structure, first, before connecting the ends of the power cables, a rubber unit and protective tube expanded by a diameter expansion retaining member are passed through the power cables and left waiting in a portion other than the ends of the power cables. After connecting the ends of the power cables, the rubber unit that was waiting on the power cables in advance is moved to the connection portion, the diameter expansion retaining member is pulled out of the rubber unit, and the rubber unit is attached to the connection portion. Next, a shielding layer is tightly wrapped around the outer periphery of the rubber unit, and a protective layer is tightly wrapped around the outer periphery of the shielding layer. After that, the protective tube that was waiting on the power cables in advance is moved to the position of the rubber unit. Next, a liquid compound is injected through an injection hole provided in the protective tube, and the compound is allowed to harden.

However, as mentioned above, when assembling conventional cable intermediate splice structures, the shielding layer is wound around the rubber unit on-site. This type of shielding layer winding work takes a long time because it is performed while supporting the two connected power cables.

Furthermore, if the shielding layer is tightly wound around the outer periphery of a rubber unit that has been expanded with a diameter expansion retainer, the expanded rubber unit will shrink in diameter when the diameter expansion retainer is pulled out of the rubber unit. As the rubber unit shrinks in diameter, the state of the shielding layer that was previously attached tightly to the rubber unit will be disrupted, making it necessary to re-wrap the shielding layer.

Japanese Patent Application Laid-Open No. 2001-37065

The objective of this disclosure is to provide a power cable intermediate connection unit and a power cable connection method that can easily form a shielding layer in a short amount of time by pulling out a diameter expansion retaining material.

[1] A power cable intermediate connection unit for assembling a cable intermediate connection structure that connects an end of a first power cable and an end of a second power cable, the power cable intermediate connection unit comprising: a diameter expansion retaining member; a rubber unit into which the diameter expansion retaining member is inserted and whose diameter is expanded by the diameter expansion retaining member; and a shielding layer provided on the outer periphery of the rubber unit and composed of a plurality of shielding wires arranged at a distance from each other.
[2] The power cable intermediate connection unit according to the above [1], wherein the diameter expansion and retention member is a spiral core.
[3] The power cable intermediate connection unit according to [1] or [2], wherein the plurality of shielding wires extend along the axial direction of the diameter expansion retaining material and are arranged around the circumferential direction of the diameter expansion retaining material.
[4] The power cable intermediate connection unit according to the above [1] or [2], wherein the plurality of shielding wires are a braid wound in a spiral shape.
[5] The power cable intermediate connection unit according to any one of [1] to [4] above, wherein one of the plurality of shielding wires has a terminal at one end.
[6] The power cable intermediate connection unit according to any one of [1] to [5] above, further comprising at least one metal roll spring that covers an outer periphery of a portion of the shielding layer in an expanded state and is electrically connected to the shielding layer.
[7] The power cable intermediate connection unit according to any one of [1] to [6] above, further comprising at least one resin pressing portion that covers the outer periphery of a portion of the shielding layer in an expanded diameter state.
[8] The power cable intermediate connection unit according to the above [7], wherein the pressing portion includes at least one of an elastic rubber band and a rubber net.
[9] A power cable connecting method comprising: a step (step 1) of connecting a first cable conductor of a first power cable and a second cable conductor of a second power cable with a conductor connecting portion; and a step (step 2) of installing a rubber unit and a shielding layer around the periphery of the conductor connecting portion using the power cable intermediate connection unit described in any one of [1] to [8] above.

This disclosure provides a power cable intermediate connection unit and a power cable connection method that can easily form a shielding layer in a short amount of time by pulling out the diameter expansion retaining material.

FIG. 1 is a schematic diagram showing an example of a power cable intermediate connection unit according to an embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG. FIG. 4 is a schematic view showing a state after the diameter expansion retaining member has been pulled out from the power cable intermediate connection unit shown in FIG. FIG. 5 is a vertical cross-sectional view showing an example of a cable intermediate connection structure assembled using the power cable intermediate connection unit of the embodiment. FIG. 6 is a schematic diagram showing another example of the power cable intermediate connection unit according to the embodiment. FIG. 7 is a schematic view showing a state after the diameter expansion retaining member has been pulled out from the power cable intermediate connection unit shown in FIG. 6. FIG.

The following provides a detailed explanation based on the embodiments.

After extensive research, the inventors focused on the configuration of the shielding layer, thereby facilitating the formation of the shielding layer by drawing out the diameter expansion retaining material and shortening the formation time.

The power cable intermediate connection unit of this embodiment is a power cable intermediate connection unit used to assemble a cable intermediate connection structure that connects the end of a first power cable and the end of a second power cable, and includes a diameter expansion retaining member, a rubber unit into which the diameter expansion retaining member is inserted and whose diameter is expanded by the diameter expansion retaining member, and a shielding layer provided on the outer periphery of the rubber unit and composed of multiple shielding wires arranged at a distance from each other.

Figure 1 is a schematic diagram showing an example of a power cable intermediate connection unit according to an embodiment. Figure 2 is a cross-sectional view taken along line A-A in Figure 1. Figure 3 is a cross-sectional view taken along line B-B in Figure 1. Figure 4 is a schematic diagram showing the state after a diameter expansion retaining member has been withdrawn from the power cable intermediate connection unit shown in Figure 1. Figure 5 is a longitudinal cross-sectional view showing an example of a cable intermediate connection structure assembled using a power cable intermediate connection unit. Figure 6 is a schematic diagram showing another example of a power cable intermediate connection unit according to an embodiment. Figure 7 is a schematic diagram showing the state after a diameter expansion retaining member has been withdrawn from the power cable intermediate connection unit shown in Figure 6.

Details of the rubber unit 3 are omitted from Figures 1, 4, and 6-7. For convenience, the terminal 50, roll spring 60, and retainer 70 are omitted from Figure 5. Also, for convenience, Figure 5 shows a side view of the first cable conductor 11a, first cable insulator 12a, first outer semiconductive layer 13a, first semiconductive tape layer 14a, first cable shielding layer 15a, and first cable sheath 16a of the first power cable 10a, and the second cable conductor 11b, second cable insulator 12b, second outer semiconductive layer 13b, second semiconductive tape layer 14b, second cable shielding layer 15b, and second cable sheath 16b of the second power cable 10b.

As shown in Figures 1 to 5, the power cable intermediate connection unit 1 of this embodiment is a jig for assembling a cable intermediate connection structure 1a that connects the end of a first power cable 10a and the end of a second power cable 10b. The power cable intermediate connection unit 1 includes a diameter expansion retaining member 10, a rubber unit 3, and a shielding layer 4.

The diameter expansion retaining member 10 that constitutes the power cable intermediate connection unit 1 supports the rubber unit 3 from its inner peripheral side while maintaining the rubber unit 3 in an expanded diameter state. The diameter expansion retaining member 10 has a hollow tubular shape, for example, a hollow cylindrical shape.

The inner diameter of the diameter expansion retaining material 10 is larger than the outer diameter of the end portions of the first power cable 10a and second power cable 10b that have been subjected to the step-stripping process. If the inner diameter of the diameter expansion retaining material 10 is smaller than or the same as the outer diameter of the end portions of the first power cable 10a and second power cable 10b that have been subjected to the step-stripping process, it will be difficult to pass the power cable intermediate connection unit 1 through the first power cable 10a and second power cable 10b when assembling the cable intermediate connection structure 1a for the power cables.

At the end of the first power cable 10a that has been stripped, as shown in Figure 5, the first cable conductor 11a, first cable insulation 12a, first outer semiconductive layer 13a, first semiconductive tape layer 14a, and first cable shielding layer 15a are exposed from the first cable sheath 16a. Similarly, at the end of the second power cable 10b that has been stripped, the second cable conductor 11b, second cable insulation 12b, second outer semiconductive layer 13b, second semiconductive tape layer 14b, and second cable shielding layer 15b are exposed from the second cable sheath 16b.

When assembling the cable intermediate connection structure 1a, the diameter expansion retaining material 10 is preferably an inner core or an expansion pipe so that it can be easily pulled out of the power cable intermediate connection unit 1. If the inner core is a spiral core, the diameter expansion retaining material 10 can be pulled out even more easily.

The rubber unit 3 that constitutes the power cable intermediate connection unit 1 is expanded in diameter by the diameter expansion retaining member 10. The rubber unit 3 has a hollow tubular shape, for example a hollow cylindrical shape. The diameter expansion retaining member 10 is inserted into the rubber unit 3. In this way, the diameter expansion retaining member 10 inserted into the rubber unit 3 allows the rubber unit 3 to maintain its expanded state.

When assembling the cable intermediate joint structure 1a for power cables, the diameter expansion retaining member 10 is pulled out of the expanded rubber unit 3, causing the rubber unit 3 to contract, and the rubber unit 3 is brought into close contact with the outer periphery of the first power cable 10a and the second power cable 10b, including the conductor connection portion 2, for example, the outer periphery of the first cable insulator 12a, the first outer semiconductive layer 13a, the second cable insulator 12b, and the second outer semiconductive layer 13b. In this way, the restoring force of the rubber unit 3 causes the expanded rubber unit 3 to contract. To contract the expanded rubber unit 3, the rubber unit 3 has radial contractibility at room temperature, for example, in the temperature range of 0°C to 40°C.

The shielding layer 4 that constitutes the power cable intermediate connection unit 1 is composed of multiple shielding wires 40. The multiple shielding wires 40 are arranged on the outer periphery of the expanded rubber unit 3. The multiple shielding wires 40 arranged on the outer periphery of the expanded rubber unit 3 are spaced apart from one another. The shielding layer 4 is made of a highly conductive metal such as copper, copper alloy, aluminum, or aluminum alloy. An adhesive (not shown) may be provided between the outer surface of the rubber unit 3 and the inner surface of the shielding layer 4 to temporarily secure the shielding layer 4 to the outer surface of the rubber unit 3.

As shown in FIG. 1, the multiple shielding wires 40 extend along the axial direction of the diameter expansion retaining material 10 and are arranged around the circumferential direction of the diameter expansion retaining material 10. For example, the multiple shielding wires 40 extending along the axial direction of the diameter expansion retaining material 10 are arranged around the entire circumferential direction of the diameter expansion retaining material 10.

Also, as shown in Figure 6, the multiple shielding wires 40 may be braided and wound in a spiral shape.

As shown in Figures 1 and 6, the multiple shielding wires 40 provided on the outer periphery of the expanded rubber unit 3 are spaced apart from one another. When the multiple shielding wires 40 are spaced apart from one another, the side surfaces 40a of the shielding wires 40 extending along the longitudinal direction of the shielding wires 40 are not in close contact with one another. However, when the shielding wires 40 are spaced apart in this manner, the multiple shielding wires 40 may cross each other.

The shielding layer 4 is provided on the outer periphery of the expanded rubber unit 3. When assembling the cable intermediate connection structure 1a, the diameter of the expanded rubber unit 3 is reduced by pulling out the diameter expansion retaining material 10 from the expanded rubber unit 3. As the rubber unit 3 reduces in diameter, the shielding wires 40 that were spaced apart are brought into close contact with each other. In this way, a shielding layer 4 is formed in which the side surfaces 40a of the shielding wires 40 are in close contact with each other. Because the state of the shielding layer 4 is not disturbed, there is no need to re-form the shielding layer 4. In this way, the shielding layer 4 can be easily formed in a short amount of time by pulling out the diameter expansion retaining material 10.

On the other hand, if the multiple shielding wires 40 in the power cable intermediate connection unit 1 are arranged closely together rather than spaced apart, the multiple shielding wires 40 that were previously arranged closely together will randomly overlap as the rubber unit 3 shrinks in diameter. This disrupts the state of the shielding layer 4 that is formed. Depending on the state of the shielding layer 4, it may be necessary to form the shielding layer 4 again.

The spacing between the multiple shielding wires 40 is set appropriately depending on the expansion rate of the rubber unit 3.

Furthermore, one of the multiple shielding wires 40 may have a terminal 50 at one end 41. The terminal 50 provided at one end 41 of one shielding wire 40 connects to the protective tube 7 shown in Figure 5. For convenience, Figure 5 does not show the connection between the terminal 50 and the protective tube 7.

The terminals 50 are pre-attached to the shielding wire 40 of the power cable intermediate connection unit 1. Therefore, there is no need to attach the terminals 50 to the shielding wire 40 at the assembly site of the cable intermediate connection structure 1a.

The power cable intermediate connection unit 1 may further include at least one metal roll spring 60 that, in an expanded diameter state, covers part of the outer periphery of the shielding layer 4 and is electrically connected to the shielding layer 4. The roll spring 60 is a cylindrical metal member. The expanded diameter roll spring 60 covers the entire outer periphery of the shielding layer 4.

As shown in the figure, the roll spring 60 covers the outer periphery of a portion of the shielding layer 4 in the axial direction of the diameter expansion retaining material 10. Here, three roll springs 60 are spaced apart at predetermined intervals along the axial direction of the diameter expansion retaining material 10.

When assembling the cable intermediate connection structure 1a, the diameter expansion retaining member 10 is pulled out of the expanded rubber unit 3, thereby reducing the diameter of the rubber unit 3. As the rubber unit 3 reduces in diameter, the multiple shielding wires 40 are brought into close contact with each other, and the roll spring 60 supports the multiple shielding wires 40 from their outer surfaces, adhering to the outer surfaces of all of the shielding wires 40 that are in close contact with each other. In this way, the multiple shielding wires 40 can be brought into close contact with each other, and the roll spring 60 can be attached to the outer surfaces of all of the shielding wires 40. All of the shielding wires 40 that make up the shielding layer 4 are reliably electrically connected via the roll spring 60.

The power cable intermediate connection unit 1 may further include at least one resin retaining portion 70 that covers a portion of the outer periphery of the shielding layer 4 in an expanded diameter state. The retaining portion 70 is annular. The expanded diameter retaining portion 70 covers the entire outer periphery of the shielding layer 4.

As shown in the figure, the retaining portion 70 covers the outer periphery of a portion of the shielding layer 4 in the axial direction of the diameter expansion retaining material 10. Here, two retaining portions 70 are spaced apart at a predetermined interval along the axial direction of the diameter expansion retaining material 10.

In its expanded diameter state, the retaining portion 70 covers the shielding layer 4 from the outer periphery. The retaining portion 70 presses the multiple shielding wires 40 toward the outer periphery of the rubber unit 3. As a result, the retaining portion 70 can further prevent the shielding wires 40 from coming off the outer periphery of the rubber unit 3.

When the power cable intermediate connection unit 1 includes a retaining portion 70, the power cable intermediate connection unit 1 may or may not include a roll spring 60. When the power cable intermediate connection unit 1 includes a roll spring 60 and a retaining portion 70, as shown in the figure, the attachment positions of the roll spring 60 and the retaining portion 70 relative to the shielding layer 4 do not overlap but are spaced apart.

When assembling the cable intermediate connection structure 1a, the diameter expansion retaining member 10 is pulled out of the expanded rubber unit 3, causing the rubber unit 3 to contract. As the rubber unit 3 contracts, the multiple shielding wires 40 are brought into close contact with each other, and the retaining portion 70 presses the multiple shielding wires 40 from the outer surface. In this way, the retaining portion 70 further prevents the shielding wires 40 from falling, forming multiple shielding wires 40 that are in close contact with each other.

When the power cable intermediate connection unit 1 is equipped with a roll spring 60 and a retaining portion 70, one end 41 of one shielding wire 40 and the terminal 50 provided at that end 41 are not restrained by the roll spring 60 or the retaining portion 70, as shown in the figure.

The retaining portion 70 preferably includes at least one of a stretchable rubber band and a rubber net. When the retaining portion 70 is made up of a rubber band or a rubber net, the retaining portion 70 is easy to attach, and the condition of the shielding wire 40 can be visually inspected when assembling the cable intermediate connection structure 1a.

Figure 5 is a longitudinal cross-sectional view showing an example of a cable intermediate connection structure 1a assembled using the power cable intermediate connection unit 1. The first power cable 10a has, from the center, a first cable conductor 11a, a first cable insulator 12a covering the outer periphery of the first cable conductor 11a, a first cable shielding layer 15a covering the outer periphery of the first cable insulator 12a, and a first cable sheath 16a covering the outer periphery of the first cable shielding layer 15a. An internal semiconductive layer (not shown) is provided on the inner periphery of the first cable insulator 12a. On the outer periphery of the first cable insulator 12a, a first external semiconductive layer 13a and a first semiconductive tape layer 14a are provided, in that order from the inside.

Like the first power cable 10a, the second power cable 10b also has, from the center, a second cable conductor 11b, a second cable insulator 12b, a second cable shielding layer 15b, and a second cable sheath 16b. An internal semiconductive layer (not shown) is provided on the inner periphery of the second cable insulator 12b. On the outer periphery of the second cable insulator 12b, a second external semiconductive layer 13b and a second semiconductive tape layer 14b are provided, in that order from the inside.

The first cable conductor 11a and the second cable conductor 11b are made of a highly conductive metal such as copper, copper alloy, aluminum, or aluminum alloy. The first cable insulator 12a and the second cable insulator 12b are made of a highly electrically insulating resin such as cross-linked polyethylene. The inner semiconductive layer, the first outer semiconductive layer 13a and the second outer semiconductive layer 13b, and the first semiconductive tape layer 14a and the second semiconductive tape layer 14b are made of a semiconductive resin or the like. The first cable shielding layer 15a and the second cable shielding layer 15b are made of a highly conductive metal such as copper, copper alloy, aluminum, or aluminum alloy. The first cable sheath 16a and the second cable sheath 16b are made of a resin such as polyethylene or polyvinyl chloride.

The first power cable 10a and the second power cable 10b are, for example, CV cables (cross-linked polyethylene insulated vinyl sheath cables). Such first power cables 10a and second power cables 10b are suitable for use as high-voltage cables and extra-high-voltage cables.

The cable intermediate joint structure 1a comprises, from the center outward, a conductor connection portion 2, a rubber unit 3, a shielding layer 4, a protective layer 5, a compound portion 6, and a protective tube 7. The conductor connection portion 2 constituting the cable intermediate joint structure 1a connects the end of the first cable conductor 11a of the first power cable 10a and the end of the second cable conductor 11b of the second power cable 10b. The cable intermediate joint structure 1a is, for example, generally symmetrical about its central axis, and at the connection portion between the first cable conductor 11a and the second cable conductor 11b, is generally symmetrical about a direction perpendicular to the axial direction of the cable intermediate joint structure 1a.

The conductor connection portion 2 connects the end of the first cable conductor 11a and the end of the second cable conductor 11b, which are exposed by step-stripping the end portions of the first power cable 10a and the second power cable 10b. For example, the conductor connection portion 2 is cylindrical. By inserting the first power cable 10a into one end of the conductor connection portion 2 and the second power cable 10b into the other end of the conductor connection portion 2 and compressing the conductor connection portion 2, the conductor connection portion 2 electrically connects the first cable conductor 11a of the first power cable 10a and the second cable conductor 11b of the second power cable 10b.

From the viewpoint of high conductivity and compressibility, the conductor connection portion 2 is preferably made of copper, a copper alloy, aluminum, or an aluminum alloy. A semiconductive tape layer or the like may be provided on the outer peripheral surface of the conductor connection portion 2 and the outer peripheral surfaces of the exposed first cable conductor 11a and second power cable 10b.

The rubber unit 3 that constitutes the cable intermediate joint structure 1a covers the outer periphery of the conductor connection portion 2. The rubber unit 3 is cylindrical and serves as the main insulating portion of the cable intermediate joint structure 1a. Here, the rubber unit 3 continuously covers the outer periphery from the first outer semiconductive layer 13a of the first power cable 10a to the second outer semiconductive layer 13b of the second power cable 10b. The rubber unit 3 is attached in an expanded state, covering the outer periphery of the first power cable 10a and the second power cable 10b, including the conductor connection portion 2. Therefore, the restoring force of the rubber unit 3 causes the inner periphery of the rubber unit 3 to adhere closely to the outer periphery, including the conductor connection portion 2.

The rubber unit 3 has a main insulating portion 31, a cylindrical inner peripheral semiconductive portion 32 provided on the inner peripheral portion of the central portion of the main insulating portion 31 in the axial direction of the cable intermediate joint structure 1a, end semiconductive portions 33 provided on both ends of the main insulating portion 31, and a cylindrical outer peripheral semiconductive portion 34 provided on the outer peripheral portion of the central portion of the axial direction of the main insulating portion 31.

The main insulating portion 31 of the rubber unit 3 covers the outer periphery from the first cable insulator 12a of the first power cable 10a to the second cable insulator 12b of the second power cable 10b. The main insulating portion 31 is made of rubber with high electrical insulation, preferably insulating silicone rubber or insulating ethylene propylene rubber.

The inner circumferential semiconductive portion 32 covers the outer periphery of the conductor connection portion 2. Each end semiconductive portion 33 is connected to the first outer semiconductive layer 13a and the second outer semiconductive layer 13b, respectively. A portion of the main insulating portion 31 is interposed between each end semiconductive portion 33 and the outer circumferential semiconductive portion 34. The end semiconductive portion 33 and the outer circumferential semiconductive portion 34 are electrically insulated. The inner circumferential semiconductive portion 32, the end semiconductive portion 33, and the outer circumferential semiconductive portion 34 are made of semiconductive rubber, preferably semiconductive silicone rubber or semiconductive ethylene propylene rubber.

In addition, a base spacer 36 is provided on each end of the rubber unit 3. The base spacer 36 forms an inclined surface between the outer peripheral surface of the first outer semiconductive layer 13a or the second outer semiconductive layer 13b and the outer peripheral surface of the main insulating part 31. A semiconductive tape layer 35 is provided in the gap around the base spacer 36.

The shielding layer 4 that constitutes the cable intermediate connection structure 1a covers the outer periphery of the rubber unit 3. The shielding layer 4 that covers the rubber unit 3 connects the first cable shielding layer 15a of the first power cable 10a or the second cable shielding layer 15b of the second power cable 10b to the outer semiconductive portion 34 of the rubber unit 3.

The protective layer 5 that constitutes the cable intermediate joint structure 1a covers the outer periphery of the shielding layer 4. The protective layer 5 that covers the shielding layer 4 protects the shielding layer 4. The protective layer 5 is made of rubber with high electrical insulation properties, such as butyl rubber.

The resin compound part 6 that constitutes the cable intermediate joint structure 1a covers the outer periphery of the protective layer 5. The compound part 6 is preferably made of a thermosetting resin with high heat dissipation and electrical insulation properties, and is more preferably made of insulating silicone rubber, urethane resin, or insulating ethylene propylene rubber.

A protective tube 7 is attached to the outer periphery of the compound section 6. The protective tube 7 is cylindrical and covers the outer periphery of the compound section 6. In this case, the protective tube 7 continuously covers the outer periphery from the first cable shielding layer 15a of the first power cable 10a to the second cable shielding layer 15b of the second power cable 10b.

Next, we will explain how to connect the power cable in this embodiment.

The power cable connection method of this embodiment includes a step (step 1) of connecting the first cable conductor of the first power cable and the second cable conductor of the second power cable using a conductor connection part, and a step (step 2) of installing a rubber unit and a shielding layer around the periphery of the conductor connection part using the above-described power cable intermediate connection unit.

In step 1, the first cable conductor 11a exposed at the end of the first power cable 10a and the second cable conductor 11b exposed at the end of the second power cable 10b are inserted into the conductor connection part 2, and the conductor connection part 2 is compressed to connect the first cable conductor 11a of the first power cable 10a and the second cable conductor 11b of the second power cable 10b.

At the end of the first power cable 10a, the first cable conductor 11a, first cable insulator 12a, first outer semiconductive layer 13a, first semiconductive tape layer 14a, and first cable shielding layer 15a are exposed from the first cable sheath 16a due to the step-stripping process. Similarly, at the end of the second power cable 10b, the second cable conductor 11b, second cable insulator 12b, second outer semiconductive layer 13b, second semiconductive tape layer 14b, and second cable shielding layer 15b are exposed from the second cable sheath 16b due to the step-stripping process.

Before connecting the first power cable 10a and the second power cable 10b, the power cable intermediate connection unit 1 is passed through the first power cable 10a or the second power cable 10b and left waiting at a part other than the end of the power cable.

In step 2, which is performed after step 1, a power cable intermediate connection unit 1 is used to install a rubber unit 3 and a shielding layer 4 on the outer periphery of the conductor connection portion 2, thereby covering the outer periphery of the conductor connection portion 2 with the rubber unit 3. After the first power cable 10a and the second power cable 10b are connected with the conductor connection portion 2, the power cable intermediate connection unit 1 is moved to the outer periphery of the conductor connection portion 2. Next, the diameter expansion retaining member 10 is removed from the power cable intermediate connection unit 1. In this way, the restoring force of the expanded rubber unit 3 causes it to contract in diameter, so that the rubber unit 3 adheres closely to the outer periphery of the first power cable 10a and the second power cable 10b including the conductor connection portion 2, for example, the outer periphery of the first cable insulator 12a, the first outer semiconductive layer 13a, the second cable insulator 12b, and the second outer semiconductive layer 13b.

Furthermore, as the rubber unit 3 shrinks in diameter, the multiple shielding wires 40 that were spaced apart come into close contact with each other. Therefore, by removing the diameter expansion retaining member 10 from the power cable intermediate connection unit 1, the rubber unit 3 is attached to the outer periphery of the first power cable 10a and the second power cable 10b, which include the conductor connection portion 2, and the shielding layer 4, which is composed of the closely-attached shielding wires 40, is attached to the outer periphery of the rubber unit 3. In this way, by using the power cable intermediate connection unit 1, the first power cable 10a and the second power cable 10b are connected, and a cable intermediate connection structure for power cables including the rubber unit 3 and the shielding layer 4 can be easily assembled in a short amount of time.

The shielding wires 40 may be held in close contact with each other by roll springs 60 to ensure that all of them are electrically connected.

In addition, to electrically connect the end of the shielding wire 40 on the rubber unit 3 to the first cable shielding layer 15a of the first power cable 10a and the second cable shielding layer 15b of the second power cable 10b, the shielding wire 40 is wound as necessary to tightly contact each other to form the shielding layer 4.

The terminal 50 provided at one end 41 of the shielding wire 40 is connected to the protective tube 7.

After step 2, the protective layer 5, compound part 6, and protective tube 7 are installed as needed.

As described above, the power cable intermediate connection unit and power cable connection method of the embodiment focus on the configuration of the shielding layer, and by arranging multiple shielding wires at intervals around the outer periphery of the rubber unit in an expanded diameter state, the shielding layer can be easily formed in a short amount of time.

Although the embodiments have been described above, the present invention is not limited to the above embodiments and includes all aspects encompassed by the concept and claims of this disclosure, and various modifications can be made within the scope of this disclosure.

REFERENCE SIGNS LIST 1 Power cable intermediate connection unit 1a Cable intermediate connection structure 2 Conductor connection portion 3 Rubber unit 4 Shielding layer 5 Protective layer 6 Compound portion 7 Protective tube 10 Diameter expansion retaining material 10a First power cable 10b Second power cable 11a First cable conductor 11b Second cable conductor 12a First cable insulation 12b Second cable insulation 13a First outer semiconductive layer 13b Second outer semiconductive layer 14a First semiconductive tape layer 14b Second semiconductive tape layer 15a First cable shielding layer 15b Second cable shielding layer 16a First cable sheath 16b Second cable sheath 31 Main insulation portion 32 Inner peripheral semiconductive portion 33 End portion semiconductive portion 34 Outer peripheral semiconductive portion 35 Semiconductive tape layer 36 Base spacer 40 Shielding wire 40a Side of shielding wire 41 One end of shielding wire 50 Terminal 60 Roll spring 70 Pressing portion

Claims (9)

A power cable intermediate splice unit for assembling a cable intermediate splice structure that connects an end of a first power cable and an end of a second power cable, comprising:
a diameter expansion holding material;
a rubber unit having a diameter expansion retaining member inserted therein and expanded by the diameter expansion retaining member;
a shielding layer provided on the outer periphery of the rubber unit and composed of a plurality of shielding wires arranged at a distance from each other. The power cable intermediate connection unit according to claim 1, wherein the diameter expansion retaining material is a spiral core. The power cable intermediate connection unit according to claim 1, wherein the plurality of shielding wires extend along the axial direction of the diameter expansion retaining member and are arranged circumferentially around the diameter expansion retaining member. The power cable intermediate connection unit according to claim 1, wherein the plurality of shielding wires are a braid wound in a spiral shape. The power cable intermediate connection unit according to claim 1, wherein one of the plurality of shielding wires has a terminal at one end. The power cable intermediate connection unit according to claim 1, further comprising at least one metal roll spring that covers the outer periphery of a portion of the shielding layer in an expanded state and is electrically connected to the shielding layer. The power cable intermediate connection unit according to claim 1, further comprising at least one resin retaining portion that covers the outer periphery of a portion of the shielding layer in an expanded state. The power cable intermediate connection unit according to claim 7, wherein the retaining portion includes at least one of a stretchable rubber band and a rubber net. a step (step 1) of connecting a first cable conductor of a first power cable and a second cable conductor of a second power cable by a conductor connection part;
A power cable connecting method, comprising: a step (step 2) of installing a rubber unit and a shielding layer around the outer periphery of the conductor connection portion using the power cable intermediate connection unit according to any one of claims 1 to 8.