Insulation units and cable joints

Abstract

To provide an insulation unit and cable intermediate connection part that can achieve high insulation performance with a simple configuration.SOLUTION: An insulation unit used in a prefabricated type cable intermediate joint part connecting two power cables comprises: an internal electrode electrically connected to the cable conductors of the power cable; a reinforced insulator having an insulating body part surrounding the internal electrode and an edge cutting part provided continuously in the axial direction of the insulating body part, and formed integrally with the internal electrode; a metal protective tube that covers the outer periphery of the insulating body part and is arranged so that the edge cutting part is exposed; a shielding part between the insulating body part and the protective tube; a resin protective cover that covers the outer surface of the edge cutting part; and terminal fittings attached to the axial ends of the edge cutting part and the protective cover.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to insulating units and cable intermediate connections, and in particular to insulating joints (IJ) that provide an edge termination at one end. [Background technology]

[0002] Conventionally, as a cable intermediate connection part for connecting two power cables (e.g., CV cables), a prefabricated cable intermediate connection part (also called a prefabricated joint) has been known in which the cable conductors of the two power cables are connected by a conductor connection tube to form a conductor connection part, and this conductor connection part is then inserted into an insulating unit to be assembled.

[0003] An insulating unit used in a prefabricated cable intermediate joint generally includes an internal electrode electrically connected to a cable conductor, a reinforcing insulator surrounding the outer circumferential surface of the internal electrode, a shielding part formed on the outer circumferential surface of the reinforcing insulator, and a protective copper tube disposed on the outer circumferential surface of the shielding part. In addition, an insulating tube, which is an insulating member, is disposed via an adapter metal fitting at one end of the insulating unit in the longitudinal direction, and the cable shielding layers of the two power cables are electrically insulated (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5074930 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, as the voltage of power cables has increased, the insulation performance (for example, dielectric strength such as impulse breakdown voltage) required of cable intermediate joints and insulating units has become more stringent.

[0006] An object of the present disclosure is to provide an insulating unit and a cable intermediate connection part that can achieve high insulation performance with a simple configuration. [Means for solving the problem]

[0007] The insulating unit according to the present disclosure comprises: An insulating unit used in a prefabricated cable intermediate joint that connects two power cables, an inner electrode electrically connected to a cable conductor of the power cable; a reinforcing insulator having an insulating body portion surrounding the internal electrode and an edge cutting portion provided continuously in an axial direction of the insulating body portion, the reinforcing insulator being integrally formed with the internal electrode; a metal protective tube that is arranged so that the edge cutting portion is exposed and covers an outer circumferential surface of the insulating body; a shielding portion interposed between the insulating body portion and the protective tube; A resin protective cover that covers the outer peripheral surface of the edge cutting portion; a terminal fitting attached to the edge cutting portion and the end portion of the protective cover in the axial direction; 、 The outer diameter of the edge cutting portion is smaller than the outer diameter of the insulating body portion, A space is formed between the edge cutting portion and the protective cover. . The insulating unit according to the present disclosure comprises: An insulating unit used in a prefabricated cable intermediate joint that connects two power cables, an inner electrode electrically connected to a cable conductor of the power cable; a reinforcing insulator having an insulating body portion surrounding the internal electrode and an edge cutting portion provided continuously in an axial direction of the insulating body portion, the reinforcing insulator being integrally formed with the internal electrode; a metal protective tube that is arranged so that the edge cutting portion is exposed and covers an outer circumferential surface of the insulating body; a shielding portion interposed between the insulating body portion and the protective tube; A resin protective cover that covers the outer peripheral surface of the edge cutting portion; a terminal fitting attached to an end portion of the edge cutting portion and the protective cover in the axial direction, the protective tube and the protective cover are each fixed to the reinforcing insulator, The protective tube and the protective cover are in contact with each other to an extent that allows dimensional variations in the reinforcing insulator to be absorbed.

[0008] The cable intermediate connection part according to the present disclosure comprises: The above-mentioned insulation unit; and a cable terminal portion accommodated in the insulation unit. Effect of the Invention

[0009] The insulating unit and cable intermediate connection part according to the present disclosure can achieve high insulation performance with a simple configuration. [Brief description of the drawings]

[0010] [Figure 1] 1 is a half-sectional view showing a cable intermediate connection part according to an embodiment of the present invention; [Diagram 2] 1 is a half-sectional view showing a cable intermediate connection part according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a partially cutaway perspective cross-sectional view showing the structure of an insulating unit. [Figure 4] FIG. 2 is an exploded perspective view showing the structure of an insulating unit. [Diagram 5] 1A and 1B are diagrams showing a connection structure between a shielding portion and a protective tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0012] Fig. 1 is a half-sectional view showing a cable intermediate connection part 1 according to an embodiment of the present disclosure. Fig. 2 is a half-sectional view showing the cable intermediate connection part 1, and shows an enlarged view of the edge-cutting structure of an insulating unit 10. In Figs. 1 and 2, only the cross sections of the components of the insulating unit 10 are hatched.

[0013] Fig. 3 is a partially cutaway perspective cross-sectional view showing the structure of the insulating unit 10. Fig. 4 is an exploded perspective view showing the structure of the insulating unit 10, with each component shown in partially cutaway perspective cross-section.

[0014] 1 and 2, the cable intermediate connection 1 includes an insulating unit 10 and a cable terminal 50. The cable intermediate connection 1 is a prefabricated cable intermediate connection that connects two power cables 51A, 51B, and is an insulated connection (IJ) having an edge-cutting structure provided at one end in the axial direction (the right side in FIG. 1).

[0015] In the following description, the side of the cable intermediate connection part 1 where the edge cutting structure is provided is referred to as the "edge cutting side", and the opposite side is referred to as the "edge not cutting side". In addition, in the description of the cable terminal part 50, the side of each of the power cables 51A and 51B that is inserted into the insulating unit 10 is referred to as the "front end side", and the opposite side is referred to as the "rear end side". That is, in the cable intermediate connection part 1, the center side of the cable intermediate connection part 1 is referred to as the "front end side", and both end sides are referred to as the "rear end side". However, in the description of the protective tube 14 described later, the terminal mounting flange 141 side is referred to as the "rear end side", and the opposite side is referred to as the "front end side". In addition, in the description of the protective cover 16 described later, since it is attached to the edge cutting side, the fixing flange 161 side is referred to as the "rear end side", and the opposite side is referred to as the "front end side".

[0016] As shown in FIG. 1, the cable terminal portion 50 is configured by attaching connection parts including a conductor connection tube 52, a stress cone 53, a compression device 54 and a cable protection fitting 55 to the respective tip portions of the power cables 51A, 51B.

[0017] The power cables 51A and 51B are, for example, extra-high voltage (e.g., 345 kV class) power cables insulated with rubber or plastic. The power cables 51A and 51B each have, from the inside, a cable conductor 511, an inner semiconductive layer (reference number omitted), a cable insulator 512, a cable outer semiconductive layer 513, a cable shielding layer (reference number omitted), and a cable sheath (reference number omitted), etc. At the cable terminal portion 50, each layer is exposed by step-stripping a predetermined length from the tip of each of the power cables 51A and 51B.

[0018] The cable conductors 511, 511 are connected by a conductor connection tube 52. The conductor connection tube 52 is made of a conductive material suitable for current flow, such as copper, aluminum, a copper alloy, or an aluminum alloy. The conductor connection tube 52 and the cable conductors 511, 511 are electrically and mechanically connected to each other by compressing the cable conductors 511, 511 with a compression tool such as a compression die while the cable conductors 511, 511 are inserted into the conductor connection tube 52. The cable conductors 511, 511 are electrically connected to the internal electrode 11 of the insulation unit 10 via the conductor connection tube 52.

[0019] The cable shielding layer of the power cable 51A on the side with insulation is electrically connected to the terminal mounting metal fitting 15 of the insulation unit 10 via a cable protection metal fitting 55. The cable shielding layer of the power cable 51B on the side without insulation is electrically connected to the protective tube 14 via a cable protection metal fitting 55.

[0020] The stress cone 53 is formed in a spindle shape and has an insulating portion (reference number omitted) at the tip end and a conductive portion (reference number omitted) at the rear end. The insulating portion is formed in a cylindrical shape from an insulating rubber material such as EP rubber, and the conductive portion is formed in a cylindrical shape from a semiconductive rubber material such as semiconductive EP rubber. The insulating portion and the conductive portion are integrally formed by molding.

[0021] The rear end (conductive part) of the stress cone 53 is connected to the cable external semiconductive layer 513 of the power cables 51A and 51B. "Connected to the cable external semiconductive layer 513 of the power cables 51A and 51B" means either a direct connection to the cable external semiconductive layer 513 or a connection to the end of the cable external semiconductive layer 513 via an end of an external semiconductive layer reproduced with a mold or conductive paint, as long as the stress cone has a predetermined performance as a cable intermediate connection part. The tip (insulating part) of the stress cone 53 has a shape corresponding to the cable housing part of the insulation unit 10. A compression device 54 and a cable protection metal fitting 55 are attached to the rear end side of the stress cone 53.

[0022] The compression device 54 includes a push pipe 541 that contacts the stress cone 53, a coil spring 542 that biases the push pipe 541 toward the stress cone 53, a push fitting 543 that holds the push pipe 541 and the coil spring 542, a shaft 544 that is attached to the rear end side of the push fitting 543 and inserted into the coil spring 542, a washer 545 that penetrates the rear end side of the shaft 544 and is fixed with a nut, and holds the coil spring 542 at its front end surface and the rear end surface of the push fitting 543, and a tension bolt 546 that penetrates the washer 545 at its rear end side and is bolted to the insulating unit 10 side at its front end side. The push pipe 541 attached to the power cable 51A on the side with edge cutting is longer in the axial direction than the push pipe 541 attached to the power cable 51B on the side without edge cutting by the amount of edge cutting structure provided. The push pipe 541 may be made of either an insulating material or a metal material.

[0023] 1 to 4, the insulating unit 10 includes an internal electrode 11, a reinforcing insulator 12, a shielding portion 13, a protective tube 14, a terminal mounting metal fitting 15, and a protective cover 16. The internal electrode 11 and the reinforcing insulator 12 are integrally formed by, for example, molding.

[0024] The internal electrode 11 is formed of a conductive material suitable for current flow, such as copper, aluminum, a copper alloy, an aluminum alloy, etc. The internal electrode 11 is electrically connected to the cable conductor 511 via a conductor connection tube 52.

[0025] The reinforcing insulator 12 is formed, for example, from a hard plastic resin material (for example, epoxy resin or FRP) with high mechanical strength. The reinforcing insulator 12 has a substantially cylindrical shape, and the inner circumferential surface forms a cable terminal accommodating portion 123. The internal electrode 11 is disposed approximately at the center of the cable terminal accommodating portion 123 in the axial direction.

[0026] The reinforcing insulator 12 has an insulating body portion 121 that surrounds the internal electrode 11, and an edge cutting portion 122 that is connected to one axial end of the insulating body portion 121. The outer diameter of the edge cutting portion 122 is smaller than the outer diameter of the insulating body portion 121, and the reinforcing insulator 12 has a two-stage cylindrical shape as a whole. The outer peripheral surface of the insulating body portion 121 is covered by the protective tube 14, and the outer peripheral surface of the edge cutting portion 122 is covered by the protective cover 16.

[0027] The axial length and outer diameter (thickness) of the edge cutting portion 122 are appropriately set according to the required insulating performance and mechanical strength. When the outer diameter of the edge cutting portion 122 is increased, the insulating performance and mechanical strength can be improved. On the other hand, when the outer diameter of the edge cutting portion 122 is reduced, the insulating performance and mechanical strength decrease, but the weight of the insulation unit 10 can be reduced.

[0028] The shielding portion 13 is formed, for example, by applying a conductive paint to the outer peripheral surface of the insulating main body portion 121. The shielding portion 13 may be formed by further wrapping a semiconductive tape or a copper mesh tape (shielding mesh) around the surface of the applied layer of the conductive paint. The shielding portion 13 is disposed on the outer peripheral surface of the insulating main body portion 121 of the reinforcing insulator 12, but is not disposed on the outer peripheral surface of the edge cutting portion 122.

[0029] The shielding portion 13 is electrically connected to the protective tube 14 and is grounded. For example, one end of a lead wire 21 such as a tin-plated soft copper braided wire is soldered to the shielding portion 13 (e.g., copper mesh tape), the other end is connected to a crimp terminal 22, and the crimp terminal 22 is screwed to the end face of the protective tube 14, thereby electrically connecting the shielding portion 13 and the protective tube 14 (see FIG. 5). By providing the shielding portion 13, the electric field is not concentrated between the internal electrode 11 and the shielding portion 13, and the internal electric field of the reinforcing insulator 12 is made uniform, thereby stabilizing the electrical characteristics.

[0030] The protective tube 14 is a metal member having a substantially cylindrical shape. The protective tube 14 is formed of a metal material such as copper, brass, or aluminum. The axial length of the protective tube 14 is substantially equal to the length of the insulating body 121.

[0031] The protective tube 14 has a terminal mounting flange 141 formed at the end on the rear end side so as to protrude radially inward. The cylindrical portion of the protective tube 14 and the terminal mounting flange 141 may be formed of separate members and integrated by brazing or the like, or may be formed of a single member. An opening 141a of the terminal mounting flange 141 fits into the cable terminal housing portion 123 of the reinforcing insulator 12. The protective tube 14 is arranged so as to cover the outer peripheral surface of the insulating body portion 121, and the terminal mounting flange 141 is fixed to the end face of the reinforcing insulator 12 on the side where the edge is not cut, i.e., the end face of the insulating body portion 121, for example, by bolting. The protective tube 14 is arranged so that the edge cutting portion 122 of the reinforcing insulator 12 is exposed. The protective tube 14 may be arranged so as to cover a part of the edge cutting portion 122.

[0032] In this embodiment, the tip end of protective tube 14 protrudes beyond insulating body 121 and covers the step between insulating body 121 and edge cutting portion 122. A resin support ring 17 is disposed at the step between insulating body 121 and edge cutting portion 122. The outer diameter of support ring 17 is approximately equal to the inner diameter of protective tube 14. The tip end of protective tube 14 is fixed to the outer circumferential surface of support ring 17 by a set screw. Support ring 17 prevents the tip end of protective tube 14 from rattling, ensuring stability.

[0033] In addition, the end portion on the tip side of the protective tube 14 is not directly fixed to the reinforcing insulator 12. In other words, the reinforcing insulator 12 is capable of displacement in the axial direction relative to the protective tube 14. This allows the reinforcing insulator 12 to thermally expand or contract in the axial direction without being restrained by the protective tube 14.

[0034] The support ring 17 has a notched groove 17a penetrating in the axial direction (thickness direction) on the outer circumferential surface. The lead wire 21 connected to the shielding portion 13 is drawn out through the notched groove 17a (see FIG. 5). Note that the notch for drawing out the lead wire 21 connected to the shielding portion 13 is not limited to a groove shape and may be a through hole.

[0035] The terminal mounting bracket 15 is a metal member having a flange shape. The terminal mounting bracket 15 is formed of a metal material such as copper, brass, or aluminum. An opening 15a of the terminal mounting bracket 15 fits into the cable terminal accommodating portion 123 of the reinforcing insulator 12. The outer diameter of the terminal mounting bracket 15 is larger than the outer diameter of the edge cutting portion 122. The terminal mounting bracket 15 is fixed to the end face of the reinforcing insulator 12 on the edge cutting side, i.e., the end face of the edge cutting portion 122, for example, by bolting. In addition, a protective cover 16 is fixed to the terminal mounting bracket 15, for example, by bolting.

[0036] The protective cover 16 is a resin member having a substantially cylindrical shape. The protective cover 16 is made of a resin material such as Somalite, glass fiber reinforced nylon, or polyvinyl chloride. The protective cover 16 prevents water and dust from entering the insulation unit 10.

[0037] The protective cover 16 has a fixing flange 161 formed at the end on the rear end side, protruding radially inward. An opening 161a of the fixing flange 161 fits the outer shape of the edge cutting portion 122. The protective cover 16 is disposed so as to cover the outer peripheral surface of the edge cutting portion 122, and the fixing flange 161 is fixed to the terminal mounting bracket 15, for example, by bolting. A seal member 19, such as an O-ring, is disposed between the fixing flange 161 and the terminal mounting bracket 15.

[0038] The inner diameter of the protective cover 16 is approximately equal to the outer diameter of the tip end of the protective tube 14, and is larger than the outer diameter of the edge cutting portion 122. A space 23 is formed between the protective cover 16 and the edge cutting portion 122. In this embodiment, the space 23 is formed by a space surrounded by the outer peripheral surface of the edge cutting portion 122, the inner peripheral surface of the protective cover 16, the tip surface of the fixing flange 161, and the rear end surface of the barrier wall 162.

[0039] The axial length of the protective cover 16 is longer than the length of the edge cutting portion 122. The protective cover 16 is disposed, for example, such that the tip end of the protective cover 16 covers the tip end of the protective tube 14. A seal member 18 such as an O-ring is disposed between the protective cover 16 and the protective tube 14.

[0040] The end of the tip side of the protective cover 16 is merely overlapped with the protective tube 14 in the radial direction, and the protective tube 14 and the protective cover 16 are not directly fixed to each other by bolts, screws, or the like. In other words, the protective tube 14 is fixed to the reinforcing insulator 12 by the terminal mounting flange 141, and the protective cover 16 is fixed to the terminal mounting bracket 15 fixed to the reinforcing insulator 12, but the protective tube 14 and the protective cover 16 are not directly fixed to each other, and the protective tube 14 and the protective cover 16 are only abutted to an extent that the dimensional fluctuation of the reinforcing insulator 12 is absorbed. As a result, the reinforcing insulator 12 can absorb the dimensional fluctuation due to the thermal expansion or thermal contraction in the axial direction during use of the cable intermediate joint 1 without being restrained by either the protective tube 14 or the protective cover 16. In addition, the variation in the axial dimension of the reinforcing insulator 12 after the internal electrode 11 and the reinforcing insulator 12 are integrally molded (so-called manufacturing tolerance) can be absorbed. When the protective cover 16 is made of a resin capable of conforming to the deformation of the reinforcing insulator 12 , it may be fixed directly to the reinforcing insulator 12 .

[0041] Although not shown in the figure, the entire outer circumferential surface of the insulating unit 10 is covered with a heat shrink tube. The tip end of the protective cover 16 and the tip end of the protective tube 14 are pressed and tightly attached by the heat shrink tube.

[0042] The protective cover 16 has a barrier wall 162 formed to protrude radially inward. An opening 162a of the barrier wall 162 fits the outer shape of the edge cutting portion 122. The barrier wall 162 is disposed near the end face on the tip side of the protective tube 14, i.e., near the crimp terminal 22 connected to the protective tube 14. The barrier wall 162 suppresses flashover between the crimp terminal 22 and the terminal mounting bracket 15 (or between the crimp terminal 22 and a bolt that fixes the fixing flange 161 to the terminal mounting bracket 15). If the axial length of the edge cutting portion 122 is sufficiently secured to prevent this flashover, the barrier wall 162 is not necessary; however, by providing the barrier wall 162, the influence of metal protrusions such as the crimp terminal 22, the lead wire 21, and the screws that secure the crimp terminal 22, which may cause flashover, can be minimized, and there is no need to secure an axial length of the edge cutting portion 122 longer than necessary, thereby reducing the axial length of the insulating unit 10 (and thus the cable intermediate connection portion 1).

[0043] In the assembly process of the cable intermediate joint 1, the tip portions of the power cables 51A and 51B are stripped in stages, and then a cable protection fitting 55, a compression device 54, and a stress cone 53 are inserted into the power cables 51A and 51B. An insulating unit 20 is inserted into the power cable 51A on the side with edge cutting (or the power cable 51B on the side without edge cutting). In this state, a conductor connection tube 52 is attached to the cable conductors 511, 511 of the power cables 51A and 51B.

[0044] Next, the insulation unit 10 and the cable terminal portion 50 are moved relative to each other in the axial direction, and are positioned and fixed so that the internal electrode 11 of the insulation unit 10 and the conductor connection tube 52 of the cable terminal portion 50 are electrically connected. Then, the stress cone 53 is moved toward the insulation unit 10, and then the compression device 54 is moved toward the stress cone 53, while compressing the coil spring 542 to press the tip of the stress cone 53 against the inner surface of the insulation main body 121, and the compression device 54 is fixed in a predetermined state.

[0045] Furthermore, the cable protection fitting 55 is bolted to the terminal mounting fitting 15 (side with edge breakage) or the terminal mounting flange 141 (side without edge breakage), and a waterproof anticorrosive layer 56 is formed on the rear end of the cable protection fitting 55. In this manner, the cable intermediate joint 1 can be assembled with relatively simple operations.

[0046] In the cable intermediate joint 1, the cable shielding layer of the power cable 51A on the side with edge termination is electrically connected to the terminal mounting bracket 15 of the insulation unit 10 via the cable protection bracket 55 and is grounded. The cable shielding layer of the power cable 51B on the side without edge termination is electrically connected to the protective tube 14 via the cable protection bracket 55 and is grounded. Since the terminal mounting bracket 15 and the protective tube 14 are physically separated by the edge termination portion 122 and the space 23, high insulation performance can be ensured by adjusting the axial lengths of these components, and the cable shielding layers of the power cables 51A and 51B can be reliably terminated.

[0047] As described above, the insulating unit 10 and the cable intermediate connection part 1 according to the embodiment have the following characteristics either alone or in appropriate combination.

[0048] That is, the insulating unit 10 is an insulating unit used in a prefabricated cable intermediate connection portion 1 that connects two power cables 51A, 51B, and includes an internal electrode 11 electrically connected to the cable conductors 511 of the power cables 51A, 51B, an insulating main body portion 121 that surrounds the internal electrode 11, and a reinforcing insulator 12 that has an edge termination portion 122 that is connected to the axial direction of the insulating main body portion 121 and is formed integrally with the internal electrode 11, a metal protective tube 14 that is arranged so that the edge termination portion 122 is exposed and covers the outer peripheral surface of the insulating main body portion 121, a shielding portion 13 that is interposed between the insulating main body portion 121 and the protective tube 14, a resin protective cover 16 that covers the outer peripheral surface of the edge termination portion 122, and a terminal mounting bracket 15 that is attached to the axial end portions of the edge termination portion 122 and the protective cover 16.

[0049] The cable intermediate connection portion 1 also includes an insulating unit 10 and a cable terminal portion 50 attached to the insulating unit 10.

[0050] The insulating unit 10 and the cable intermediate connection part 1 can achieve high insulating performance with a simple configuration. Specifically, the desired insulating performance can be easily achieved by adjusting the axial length of the edge cutting part 122. Furthermore, the cable intermediate connection part 1 omits the end embedded electrode and insulating tube in the cable intermediate connection part described in Patent Document 1, resulting in a simple configuration.

[0051] In addition, in the insulating unit 10, the outer diameter of the edge cutting portion 122 is smaller than the outer diameter of the insulating main body portion 121, and a space 23 is formed between the edge cutting portion 122 and the protective cover 16. This makes it possible to reduce the weight of the insulating unit 10 while ensuring high insulating performance.

[0052] In the insulating unit 10, the protective tube 14 and the protective cover 16 are fixed to the reinforcing insulator 12, and the protective tube 14 and the protective cover 16 are in contact with each other to an extent that allows dimensional variations in the reinforcing insulator 12 to be absorbed. This allows the reinforcing insulator 12 to thermally expand or contract without being restrained by the protective tube 14 and the protective cover 16. In other words, even if the reinforcing insulator 12 thermally expands or contracts, no internal stress is generated in the reinforcing insulator 12, and deterioration due to thermal deformation can be suppressed. In addition, since variations in the axial dimension of the reinforcing insulator 12 due to manufacturing tolerances can be absorbed, the insulating unit 10 (cable intermediate joint 1) can be easily formed.

[0053] Furthermore, the insulation unit 10 includes a support ring 17 (resin ring) disposed on the outer circumferential surface of the edge cutting portion 122, and the axial end of the protective tube 14 is fixed to the outer circumferential surface of the support ring 17. This allows displacement of the reinforcing insulator 12 relative to the protective tube 14, while suppressing wobbling of the end on the tip side of the protective tube 14, thereby improving stability.

[0054] Furthermore, in the insulating unit 10, the support ring 17 (resin ring) has a notch groove 17a (notch) through which the shielding portion 13 can be pulled out, and the shielding portion 13 is pulled out from the notch groove 17a and connected to the end face of the protective tube 14 using a crimp terminal 22. This allows the shielding portion 13 to be pulled out and reliably connected to the protective tube 14, and also simplifies the connection work compared to the conventional case of connecting by soldering.

[0055] Moreover, in the insulating unit 10, the protective cover 16 has a barrier wall 162 formed to protrude radially inward and disposed in the vicinity of the end face of the protective tube 14 to which the crimp terminal 22 is connected. This makes it possible to prevent flashover caused by metal protrusions such as the crimp terminal 22, the lead wire 21, and the screws that fix the crimp terminal 22, and ensure high insulation performance.

[0056] The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the above embodiment and can be modified within the scope of the gist of the invention.

[0057] For example, in the embodiment, in the reinforcing insulator 12, the outer diameter of the edge cutting portion 122 is smaller than the outer diameter of the insulating body portion 121, but the outer diameters of the edge cutting portion 122 and the insulating body portion 121 may be equal to each other. In other words, the space 23 does not have to be formed between the edge cutting portion 122 and the protective cover 16.

[0058] In addition, in the embodiment, the tip end of the protective tube 14 is fixed to the support ring 17, but the support ring 17 may be omitted and the protective tube 14 may be pressed against the reinforcing insulator 12 by a heat shrink tube provided on the outermost layer.

[0059] In the embodiment, the protective tube 14 and the protective cover 16 are provided with heat shrink tubing on their outer peripheries. However, instead of the heat shrink tubing, a tape-wrapped layer formed by winding insulating tape or the like may be used.

[0060] Also, for example, an insulating intervening material may be placed in space 23 as long as the outer peripheral surface of edge cutting portion 122 has edge cutting performance.

[0061] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0062] 1 Cable intermediate joint 10 Isolation Unit 11 Internal electrode 12 Reinforcing insulation 121 Insulating body 122 Edge cutting section 13 Shielding section 14 Protection tube 15 Terminal mounting bracket 16 Protective cover 17 Support ring (resin ring) 21 Leader Line 22 Crimp terminal 23 Space 50 Cable terminal 51A, 51B Power Cable 511 Cable conductor

Claims

1. An insulating unit for use in a prefabricated cable intermediate joint for connecting two power cables, comprising: an inner electrode electrically connected to a cable conductor of the power cable; a reinforcing insulator having an insulating body portion surrounding the internal electrode and an edge cutting portion provided continuously in an axial direction of the insulating body portion, the reinforcing insulator being integrally formed with the internal electrode; a metal protective tube that is arranged so that the edge cutting portion is exposed and covers an outer circumferential surface of the insulating body; a shielding portion interposed between the insulating body portion and the protective tube; A resin protective cover that covers the outer peripheral surface of the edge cutting portion; a terminal fitting attached to an end portion of the edge cutting portion and the protective cover in the axial direction, The outer diameter of the edge cutting portion is smaller than the outer diameter of the insulating body portion, A space is formed between the edge cutting portion and the protective cover. Insulation unit.

2. An insulating unit for use in a prefabricated cable intermediate joint that connects two power cables, comprising: an inner electrode electrically connected to a cable conductor of the power cable; a reinforcing insulator having an insulating body portion surrounding the internal electrode and an edge cutting portion provided continuously in an axial direction of the insulating body portion, the reinforcing insulator being integrally formed with the internal electrode; a metal protective tube that is arranged so that the edge cutting portion is exposed and covers an outer circumferential surface of the insulating body; a shielding portion interposed between the insulating body portion and the protective tube; A resin protective cover that covers the outer peripheral surface of the edge cutting portion; a terminal fitting attached to an end portion of the edge cutting portion and the protective cover in the axial direction, the protective tube and the protective cover are each fixed to the reinforcing insulator, The protective tube and the protective cover are in contact with each other to an extent that dimensional fluctuations of the reinforcing insulator can be absorbed. Insulation unit.

3. the protective tube and the protective cover are each fixed to the reinforcing insulator, The protective tube and the protective cover are in contact with each other to an extent that dimensional fluctuations of the reinforcing insulator can be absorbed. The insulating unit of claim 1 .

4. A resin ring is provided on an outer circumferential surface of the edge cutting portion, The axial end of the protective tube is fixed to an outer circumferential surface of the resin ring. An insulating unit according to claim 2 or 3.

5. the resin ring has a notch through which the shielding portion can be pulled out, The shielding portion is pulled out from the notch and connected to the end surface of the protective tube using a crimp terminal.

5. The insulating unit according to claim 4.

6. The protective cover has a barrier wall formed to protrude radially inward and disposed near the end surface to which the crimp terminal is connected.

6. An insulating unit according to claim 5.

7. An insulating unit according to claim 1 or 2; A cable terminal portion attached to the insulation unit. Cable intermediate connection.

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