Cable termination structure

Abstract

To provide a cable termination connection structure capable of stably maintaining insulation quality thereof.SOLUTION: A cable termination connection structure includes: a power cable; a conductor fixing metal fitting with the front end of a cable conductor being compression-jointed; a bushing having the power cable inserted thereto while fixing the front end of the cable conductor by the conductor fixing metal fitting; a shield part provided on the inner periphery of the bushing and electrically shielding a range from the front end side of the exposed cable conductor to a part of a cable insulation layer; a stopper surrounding the outer periphery of the cable insulation layer and locked to the rear end side of the shield part; an insulation cylinder provided to surround the outer peripheries of the cable insulation layer and a cable external semiconductive layer in the bushing and relaxing the electric field around the power cable 100; and a pressure mechanism for pressing the rear end side in the axial direction of the insulation cylinder to bring the insulation cylinder into close contact with the inner periphery surface of the bushing while making the front end in the axial direction of the insulation cylinder abut the stopper. The stopper is structured to suppress shrink-back in which the cable insulation layer shrinks in a direction to be separated from the front end of the cable conductor along the central axis.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cable termination structure. [Background technology]

[0002] In substations, power plants, and the like, gas insulated switchgear (GIS) that switches current in insulating gas, or transformers that change voltage, are provided with cable termination connection structures to which power cables are connected (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-252910 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to stably maintain the insulation properties of a cable termination structure. [Means for solving the problem]

[0005] According to one aspect of the present invention, a power cable having a cable conductor, a cable insulating layer, and a cable outer semiconductive layer, the layers being stripped stepwise in this order in an axial direction of the cable conductor; a conductor fixing bracket to which the tip of the cable conductor is compression-connected; a porcelain tube through which the power cable is inserted while the tip of the cable conductor is fixed by the conductor fixing metal fitting; a shield portion provided on an inner periphery of the porcelain bushing and electrically shielding a region from a tip side of the exposed cable conductor to a part of the cable insulating layer; a stopper that surrounds the outer periphery of the cable insulating layer and is engaged with the rear end side of the shield portion; an insulating tube provided in the porcelain bushing so as to surround the outer periphery of the cable insulating layer and the cable outer semiconductive layer, and which reduces an electric field around the power cable; a pressing mechanism that presses a rear end side of the insulating tube in the axial direction so that the insulating tube is in close contact with the inner peripheral surface of the porcelain tube while abutting the front end of the insulating tube in the axial direction against the stopper; Equipped with The stopper is configured to suppress shrink-back, which is shrinkage of the cable insulation layer in a direction away from the tip of the cable conductor along the central axis. A cable termination structure is provided. [Effects of the Invention]

[0006] According to the present invention, the insulation properties of the cable termination structure can be stably maintained. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a cable termination structure according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an enlarged portion of FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view 1 illustrating a method for manufacturing a cable termination structure according to the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view 2 illustrating a method for manufacturing a cable termination structure according to the first embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic cross-sectional view 3 illustrating a method for manufacturing a cable termination structure according to the first embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic cross-sectional view 4 illustrating a method for manufacturing a cable termination structure according to the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an enlarged portion of a cable termination structure according to the second embodiment of the present disclosure. [Figure 8] FIG. 8 is a schematic cross-sectional view showing an enlarged portion of a cable termination structure according to a third embodiment of the present disclosure. [Figure 9] FIG. 9 is a schematic cross-sectional view showing the cable termination structure of Comparative Example 1. As shown in FIG. [Figure 10] FIG. 10 is a schematic cross-sectional view showing the cable termination structure of Comparative Example 2. As shown in FIG. [Figure 11] FIG. 11 is a schematic cross-sectional view showing an enlarged portion of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Description of the embodiments of the present disclosure] <Knowledge gained by the inventors> First, the findings of the inventors will be explained.

[0009] The cable termination structures of Comparative Examples 1 and 2 will be described with reference to Figures 9 to 11. Figures 9 and 10 are schematic cross-sectional views showing the cable termination structures of Comparative Examples 1 and 2, respectively. Figure 11 is a schematic cross-sectional view showing an enlarged portion of Figure 10.

[0010] As shown in FIG. 9, the cable termination structure 92 of the first comparative example includes a power cable 100 , a porcelain tube 932 , a shield part 934 , a stopper 960 , an insulating tube 940 , and a pressing mechanism 950 .

[0011] The power cable 100 is stripped in stages from the tip along the axial direction and inserted into a porcelain tube 932. A ring-shaped stopper 960 is engaged with the rear end of the shield portion 934 inside the porcelain tube 932. The insulating tube 940 is configured to reduce the electric field around the power cable 100. A pressing mechanism 950 presses the insulating tube 940 toward the stopper 960.

[0012] Here, the cable insulation layer 130 of the power cable 100 shrinks in a direction away from the tip of the cable conductor 110 along the central axis. Such axial shrinkage of the cable insulation layer 130 is called "shrink-back." The following are thought to be the causes of shrink-back.

[0013] In the manufacturing process of the power cable 100, the cable conductor 110 is fed out in the axial direction, while the outer periphery of the cable conductor 110 is coated with molten polyethylene, and the coated polyethylene is cooled to form the cable insulation layer 130. At this time, the polyethylene constituting the cable insulation layer 130 solidifies as the cable conductor 110 moves in the axial direction, so stress that stretches the cable insulation layer 130 in the axial direction remains in the cable insulation layer 130. As a result, when the cable insulation layer 130 is cut for termination connection of the power cable 100, the stress that had been stretching the cable insulation layer 130 in the axial direction is released by the cutting, and the cable insulation layer 130 may shrink in the axial direction.

[0014] Furthermore, in the cable termination connection structure 92, a so-called "heat cycle" occurs in which the temperature of the power cable 100 inside the porcelain tube 320 changes due to heat generated by the passage of current through the power cable 100 or changes in the outside air temperature around the structure. When the power cable 100 is cooled after the heat cycle, the release of stress that had stretched the cable insulation layer 130 in the axial direction is promoted, and the cable insulation layer 130 may contract in the axial direction.

[0015] However, in the cable termination connection structure 92 of Comparative Example 1, since the equipment to be installed, such as a GIS, is large, the length L1 from the cut end surface of the cable insulating layer 130 to the end of the insulating tube 940 is sufficiently long. Therefore, even if the cable insulating layer 130 shrinks back, the length L1 from the end surface of the cable insulating layer 130 to the end of the insulating tube 940 is ensured to be at least a certain length.

[0016] In contrast to this, in recent years, there has been a trend toward smaller GIS sizes, and there has been a demand for compact cable termination connection structures, as in Comparative Example 2.

[0017] 10, for example, in the cable termination structure 94 of Comparative Example 2, the cut end surface of the cable insulating layer 130 and the insulating tube 940 are close to each other. That is, the length L2 from the cut end surface of the cable insulating layer 130 to the end of the insulating tube 940 is shorter than the length L1 in the cable termination structure 92 of Comparative Example 1 described above. This makes it possible to make the cable termination structure 94 compact.

[0018] However, in Comparative Example 2, as shown in FIG. 11 , when shrinkage of the cable insulating layer 130 occurs, the leading end surface of the cable insulating layer 130 may move rearward beyond the leading end of the insulating tube 940. When such movement occurs, a gap is formed between the leading end surface of the cable insulating layer 130 and the stopper 960. At this time, because the pressing mechanism 950 presses the insulating tube 940 toward the stopper 960, the leading end of the insulating tube 940 enters the gap between the leading end surface of the cable insulating layer 130 and the stopper 960. This may result in a gap being formed between the outer circumferential surface of the insulating tube 940 and the inner circumferential surface of the porcelain tube 932. As a result, the electric field around the insulating tube 940 is not sufficiently alleviated, making it difficult to maintain the insulation properties of the cable termination connection structure 94.

[0019] Therefore, it has been desired to reduce the size of a cable termination structure while stably maintaining the insulation properties of the cable termination structure.

[0020] The present disclosure is based on the above findings made by the present inventors.

[0021] <Embodiments of the present disclosure> Next, embodiments of the present disclosure will be listed and described.

[0022] [1] A cable termination structure according to one aspect of the present disclosure includes: a power cable having a cable conductor, a cable insulating layer, and a cable outer semiconductive layer, the layers being stripped stepwise in this order in an axial direction of the cable conductor; a conductor fixing bracket to which the tip of the cable conductor is compression-connected; a porcelain tube through which the power cable is inserted while the tip of the cable conductor is fixed by the conductor fixing metal fitting; a shield portion provided on an inner periphery of the porcelain bushing and electrically shielding a region from a tip side of the exposed cable conductor to a part of the cable insulating layer; a stopper that surrounds the outer periphery of the cable insulating layer and is engaged with the rear end side of the shield portion; an insulating tube provided in the porcelain bushing so as to surround the outer periphery of the cable insulating layer and the cable outer semiconductive layer, and which reduces an electric field around the power cable; a pressing mechanism that presses a rear end side of the insulating tube in the axial direction so that the insulating tube is in close contact with the inner peripheral surface of the porcelain tube while abutting the front end of the insulating tube in the axial direction against the stopper; Equipped with The stopper is configured to suppress shrink-back, which is shrinkage of the cable insulation layer in a direction away from the tip of the cable conductor along the central axis. This configuration makes it possible to stably maintain the insulation properties of the cable termination structure.

[0023] [2] In the cable termination structure described in [1] above, The stopper is a biting portion that bites radially inward from the outer periphery of the exposed cable insulation layer; a contact portion that is engaged with the rear end side of the shield portion and that, in a state in which the axial front end of the insulating tube is in contact with the contact portion, restricts movement of the biting portion in a direction away from the front end of the cable conductor between the rear end of the shield portion and the front end of the insulating tube in the axial direction; It has. According to this configuration, shrink-back of the cable insulating layer can be stably suppressed.

[0024] [3] In the cable termination structure described in [2] above, The biting portion is formed in a ring shape so as to surround the outer periphery of the cable insulating layer, and has an inner diameter smaller than the outer diameter of the cable insulating layer. This configuration makes it possible to suppress shrink-back of the cable insulating layer in a well-balanced manner.

[0025] [4] In the cable termination structure described in [2] above, The biting portion is configured as a male screw and is screwed radially inward from the outer periphery of the exposed cable insulation layer. According to this configuration, the biting portion can be firmly inserted into the cable insulating layer.

[0026] [5] In the cable termination structure described in [1] above, The stopper is engaged with the rear end side of the shield portion, and is configured to be able to be abutted by the axial tip of the insulating tube and to bite radially inward from the outer periphery of the cable insulating layer. This configuration allows for a reduction in costs associated with the stopper.

[0027] [6] In the cable termination connection structure according to any one of [1] to [5] above, The stopper has a rear end surface that comes into surface contact with the axial tip end surface of the insulating cylinder. According to this configuration, the insulating cylinder can be pressed against the stopper without biasing the stress with which the insulating cylinder abuts against the stopper.

[0028] [Details of the embodiments of the present disclosure] Next, embodiments of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0029] <First embodiment of the present invention> (1) Cable termination structure A cable termination structure 10 according to this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic cross-sectional view showing the cable termination structure according to this embodiment. Fig. 2 is a schematic cross-sectional view enlarging a portion of Fig. 1. Note that Figs. 1 and 2 omit the structure of one half of the cable termination structure 10 across the central axis of the power cable 100. Furthermore, Figs. 1 and 2 show the side of the power cable 100 rather than a cross section.

[0030] In the following description, the "front end" refers to the end that is inserted into the GIS, and the "rear end" refers to the end that is farther from the front end.

[0031] The "axial direction" of the power cable 100 refers to the direction of the central axis of the power cable 100, and can be rephrased as the "longitudinal direction." The "radial direction" of the power cable 100 refers to the direction from the central axis of the power cable 100 toward the outer periphery, and can be rephrased as the "short direction" in some cases. The "circumferential direction" of the power cable 100 refers to the direction along the outer or inner periphery of the power cable 100.

[0032] The same terms as those for the power cable 100 can also be used for the cylindrical porcelain bushing 320 and the like.

[0033] The cable termination structure (gas insulated termination, EB-G) 10 of this embodiment is configured to connect a power cable 100 to a gas insulated switchgear (partially shown by dotted lines; hereinafter also referred to as GIS). The GIS is configured to switch current in, for example, an insulating gas. The insulating gas is, for example, sulfur hexafluoride (SF6).

[0034] 1, a cable termination structure 10 of this embodiment includes, for example, a power cable 100, a conductor fixing bracket 240, a porcelain tube 320, a shield part 340, a stopper 600, an insulating tube 400, a pressing mechanism 500, and a protective cover 700. Note that the members attached to the power cable 100 may be collectively referred to as "accessory members."

[0035] [Power cable] 1, the power cable 100 is configured as a solid insulated cable that is a high-voltage power transmission cable. An example of the power cable 100 is a CV cable (Crosslinked polyethylene insulated PVC sheathed cable, also known as an XLPE cable).

[0036] The power cable 100 has, for example, a conductor (cable conductor) 110, a cable inner semiconductive layer (not shown), a cable insulating layer 130, a cable outer semiconductive layer 140, a cable metal tube 150, and a cable sheath 160, in this order from the central axis side of the cable conductor 110 to the outer periphery side.

[0037] The power cable 100 is stripped in stages (so-called "stage stripping") from the axial tip of the cable conductor 110 to the opposite side. That is, the cable conductor 110, the cable inner semiconductive layer, the cable insulating layer 130, the cable outer semiconductive layer 140, the cable metal tube 150, and the cable sheath 160 are exposed in this order from the tip side of the cable conductor 110 to the opposite side.

[0038] [Conductor fixing bracket (conductor lead rod)] For example, a conductor fixing bracket 240 is attached to the power cable 100 that has been stripped in stages. The tip of the exposed cable conductor 110 is compression-connected to the base end side opposite to the tip of the conductor fixing bracket 240. The conductor fixing bracket 240 is fixed to the tip side of the porcelain tube 320 in the axial direction, as will be described later.

[0039] [Porcelain tube, shield part] The porcelain bushing 320 is formed of, for example, a cylindrical body having a truncated cone shape. The outer portion of the porcelain bushing 320 is formed of an insulator. Examples of the insulator that forms the outer portion of the porcelain bushing 320 include epoxy.

[0040] The tip of the cable conductor 110 is fixed to the axial tip (reduced diameter side) of the porcelain tube 320 by a conductor fixing metal fitting 240, and the power cable 100, which is stripped in stages, is inserted into the porcelain tube 320. With this configuration, it is possible to ensure insulation around the power cable 100, which is stripped in stages.

[0041] Meanwhile, an expanded diameter flange portion 360 is provided at the rear end (base end) of the porcelain bushing 320. The porcelain bushing 320 is inserted into the GIS, and the flange portion 360 abuts against the bottom plate of the GIS and is fixed to the bottom plate with bolts.

[0042] The shield part 340 is provided, for example, on the inner periphery of the porcelain tube 320. The shield part 340 is made of, for example, aluminum or an aluminum alloy, and is molded to be integrated with the porcelain tube 320.

[0043] The shield part 340 extends in a skirt shape from the axial tip to the middle position of the porcelain tube 320 within the porcelain tube 320. The shield part 340 is electrically connected to and fixed to the cable conductor 110 via a conductor fixing bracket 240, for example.

[0044] With this configuration, the shield portion 340 is at the same potential as the cable conductor 110 via the conductor fixing bracket 240, and is configured to electrically shield the area from the tip side of the exposed cable conductor 110 to a part of the cable insulation layer 130.

[0045] A locking surface 342 having a normal line along the central axis of the porcelain tube 320 is provided on the inner periphery of the rear end side of the shield part 340. A stopper 600 is locked to the locking surface 342.

[0046] [Stopper] The stopper 600 is attached to the outside of the power cable 100 so as to surround the outer periphery of the cable insulating layer 130. Furthermore, the stopper 600 is, for example, locked to the locking surface 342 at the rear end of the shield part 340 as described above. The stopper 600 of this embodiment will be described in detail later.

[0047] [Insulating tube] The insulating tube 400 is arranged within the porcelain tube 320 to surround the outer periphery of the cable insulating layer 130 and the cable outer semiconductive layer 140, and is configured to reduce the electric field around the power cable 100 that has been stripped in stages.

[0048] Specifically, insulating tube 400 has, for example, an insulator 420 and a semiconductive layer 440. These are integrally molded into a cylindrical shape. Insulator 420 is made of, for example, insulating rubber. Meanwhile, semiconductive layer 440 is made of, for example, semiconductive rubber. Semiconductive layer 440 has a tapered shape and is provided so as to expand in diameter in the axial direction from the rear end side to the front end side of insulating tube 400 (forming a so-called stress cone).

[0049] On the inner peripheral side of the insulating tube 400, the insulator 420 is disposed in contact with the outer peripheral surface of the exposed cable insulating layer 130, and the semiconductive layer 440 is disposed in contact with the outer peripheral surface of the exposed cable outer semiconductive layer 140. With this configuration, the enlarged diameter of the semiconductive layer 440 allows equipotential lines to be evenly distributed around the exposed cable outer semiconductive layer 140, thereby suppressing electric field concentration.

[0050] Meanwhile, the outer peripheral surface of the insulating tube 400 is pressed by a pressing mechanism 500 described below to be tightly attached to the inner peripheral surface of the porcelain tube 320. This ensures insulation between the insulating tube 400 and the porcelain tube 320.

[0051] In this embodiment, the cable termination structure 10 is compact, and the cut end surface of the cable insulating layer 130 is close to the insulating tube 940. That is, the length L from the end surface of the cable insulating layer 130 to the end of the insulating tube 400 is, for example, 0 mm or more and 50 mm or less.

[0052] [Pressing mechanism] The pressing mechanism 500 is configured to be able to press the axial rear end side of the insulating tube 400, for example, so as to abut the axial tip of the insulating tube 400 against the stopper 600 while tightly adhering the insulating tube 400 to the inner surface of the porcelain tube 320.

[0053] Specifically, the pressing mechanism 500 includes, for example, a contact member 520, a shaft 540, a spring 542, a stud bolt 560, and a pressing plate 570.

[0054] The abutting member 520 is configured as a trumpet-shaped member that surrounds the periphery of the power cable 100, and is made of, for example, a copper alloy, aluminum, or fiber-reinforced plastic (FRP). The abutting member 520 has a tapered surface that conforms to the outer peripheral surface of the rear end side of the insulating tube 400, and is configured to abut against the outer peripheral surface of the rear end side of the insulating tube 400.

[0055] Meanwhile, a shaft 540 is provided on the rear end side of the abutting member 520 along the axial direction of the abutting member 520. A spring 542 is fitted onto the shaft 540. The tip of the spring 542 abuts against the rear end side of the abutting member 520. Meanwhile, a pressing plate 570 abuts against the rear end of the spring 542. The shaft 540 passes through the pressing plate 570. Furthermore, a stud bolt 560 is inserted into the pressing plate 570 at a position different from that of the shaft 540. The stud bolt 560 is fixed to the flange portion 360 at the rear end of the porcelain tube 320. When a nut (number not shown) of the stud bolt 560 is tightened, the pressing plate 570 is pressed and the spring 542 is compressed. The repulsive force of the compressed spring 542 presses the insulating tube 400 via the abutting member 520 , and the outer circumferential surface of the insulating tube 400 can be brought into tight contact with the inner circumferential surface of the porcelain tube 320 .

[0056] [Protective cover] The protective cover 700 is provided, for example, to surround the power cable 100 and the pressing mechanism 500 and is configured to protect the pressing mechanism 500. The protective cover 700 is provided, for example, as a separate body from the pressing mechanism 500, and the front end of the protective cover 700 is attached to the pressing mechanism 500 by a predetermined metal fitting. Meanwhile, at the rear end of the protective cover 700, the gap between the protective cover 700 and the outer periphery of the power cable 100 is sealed by a sealing member (reference number not shown).

[0057] (2) Stopper The stopper 600 of this embodiment will be described with reference to FIG.

[0058] As shown in FIG. 2, the stopper 600 of this embodiment is configured to suppress shrink-back, which is shrinkage of the cable insulating layer 130 in a direction away from the tip of the cable conductor 110 along the central axis, for example.

[0059] The stopper 600 has a strength sufficient to suppress the shrink-back force of the cable insulating layer 130. The material of the stopper 600 is not limited as long as it satisfies the above-mentioned strength, but examples thereof include metal and resin.

[0060] Specifically, the stopper 600 of this embodiment has, for example, a biting portion 620 and a contact portion 640.

[0061] The biting portion 620 is configured, for example, to bite radially inward from the outer periphery of the exposed cable insulating layer 130. In this way, the biting portion 620 is fixed to the cable insulating layer 130.

[0062] The biting portion 620 of this embodiment is configured, for example, in a ring shape (doughnut plate shape) so as to surround the outer periphery of the cable insulating layer 130, and has an inner diameter smaller than the outer diameter of the cable insulating layer 130. A groove 138 is provided in the outer periphery of the cable insulating layer 130 along the circumferential direction, over the entire outer periphery. Note that the groove 138 of the cable insulating layer 130 must not reach the cable conductor 110. The width of the groove 138 of the cable insulating layer 130 is equal to the thickness of the biting portion 620 or is several millimeters wider. With this configuration, the biting portion 620 can be inserted into the groove 138 of the cable insulating layer 130 and fitted into the groove 138.

[0063] Furthermore, the biting portion 620 of this embodiment is divided into a plurality of parts, for example, across a cross section including the central axis of the biting portion 620. For example, the biting portion 620 is split into halves (divided into two equal parts). This allows the halves of the biting portion 620 to be joined together in a ring shape, and the biting portion 620 can be easily fitted into the groove portion 138 of the cable insulating layer 130.

[0064] The contact portion 640 is configured in a ring shape so as to surround the outer periphery of the cable insulating layer 130. The contact portion 640 is configured, for example, to be engaged with the rear end side of the shield portion 340 and to be contacted by the axial tip of the insulating tube 400.

[0065] In this embodiment, as described above, the abutment portion 640 is engaged with the rear end side of the shield portion 340, and is configured to restrict movement of the biting portion 620 in a direction away from the tip of the cable conductor 110 between the rear end of the shield portion 340 and the axial tip of the insulating tube 400 when the abutment portion 640 is in contact with the axial tip of the insulating tube 400.

[0066] Specifically, a cross section of one side of the abutting portion 640 sandwiching the central axis thereof is configured, for example, as an L-shape. The abutting portion 640 has, for example, a cylindrical portion 642 and a disk portion 644. The axial tip of the cylindrical portion 642 is engaged with the rear end side of the shield portion 340. The outer peripheral surface of the cylindrical portion 642 is in contact with the inner peripheral surface of the porcelain tube 320. The donut-shaped disk portion 644 is connected to the axial rear end of the cylindrical portion 642 and extends radially inward of the cylindrical portion 642. The disk portion 644 has a rear end surface 644b and a front surface 644f. The rear end surface 644b of the disk portion 644 has a normal line along the central axis of the disk portion 644, and is in surface contact with the axial tip surface of the insulating tube 400. On the other hand, a front surface 644f of the disk portion 644 is in contact with the biting portion 620 and is configured to restrict movement of the biting portion 620 in a direction away from the tip of the cable conductor 110.

[0067] In this way, by restricting the axial movement of the biting portion 620 by the abutting portion 640, shrink-back of the cable insulating layer 130 can be stably suppressed.

[0068] (3) Manufacturing method of cable termination structure (cable termination method) Next, a method for manufacturing a cable termination structure according to this embodiment will be described with reference to Figures 1 and 3 to 6. Figures 3 to 6 are schematic cross-sectional views 1 to 4, respectively, illustrating the method for manufacturing a cable termination structure according to this embodiment.

[0069] The manufacturing method of the cable termination structure 10 of this embodiment includes, for example, a preparation step S10, an accessory member arrangement step S20, a porcelain bushing insertion step S30, a pressing step S40, and a sealing step S50.

[0070] (S10: Preparation process) First, a power cable 100 to be connected to a GIS is prepared as shown in Fig. 3. The power cable 100 is stripped stepwise in the axial direction from the tip of the cable conductor 110 to expose the cable conductor 110, the cable insulating layer 130, and the cable outer semiconducting layer 140 in this order.

[0071] Also, the porcelain bushing 320 is prepared. The porcelain bushing 320 is inserted into the GIS, and the flange portion 360 is fixed to the GIS.

[0072] (S20: Accessory parts placement process) Next, the accessories including the conductor fastener 240, the insulating tube 400, the stopper 600 and the pressing mechanism 500 are placed (attached) to the power cable 100.

[0073] Specifically, as shown in FIG. 3, the tip of the exposed cable conductor 110 is compression-connected to the base end side of the conductor fastener 240 opposite to the tip.

[0074] Next, as shown in FIG. 4, the pressing mechanism 500 with the protective cover 700 attached thereto is passed through the power cable 100 and is retracted to a position corresponding to the rear end side of the insulating tube 400 that will be arranged in a subsequent process.

[0075] After the pressing mechanism 500 is placed, the insulating tube 400 is passed over the power cable 100 and placed so as to surround the outer periphery of the cable insulating layer 130 and the cable outer semiconductive layer 140 .

[0076] Once the insulating tube 400 is positioned as described above, the stopper 600 is placed so as to surround the outer periphery of the cable insulating layer 130, and the axial tip of the insulating tube 400 is placed in contact with the stopper 600 or at a position slightly away from the stopper 600.

[0077] At this time, in this embodiment, the stopper 600 is arranged so as to suppress shrink-back, which is shrinkage of the cable insulating layer 130 in a direction away from the tip of the cable conductor 110 along the central axis.

[0078] Specifically, grooves 138 are cut along the entire outer periphery of cable insulating layer 130 .

[0079] After the groove 138 is formed, the ring-shaped contact portion 640 is passed through the power cable 100, and the contact portion 640 is arranged so as to surround the outer periphery of the cable insulating layer 130. At this time, the rear end surface 644b of the contact portion 640 is brought into contact with the axial tip of the insulating tube 400.

[0080] After the abutting portion 640 is positioned, the half of the biting portion 620 is bitten into the groove portion 138 of the cable insulating layer 130 and fitted into the groove portion 138.

[0081] After the abutting portion 640 and the biting portion 620 are positioned, the positions of the abutting portion 640 and the insulating tube 400 are adjusted again. At this time, the abutting portion 640 is positioned so that the abutting portion 640 will be locked to the rear end side of the shielding portion 340 in a subsequent process, and the axial tip of the insulating tube 400 is in abutting contact with the abutting portion 640, while restricting movement of the biting portion 620 in a direction away from the tip of the cable conductor 110 between the rear end of the shielding portion 340 and the axial tip of the insulating tube 400.

[0082] (S30: Porcelain tube insertion process) Next, as shown in FIG. 5, the power cable 100 is inserted into the porcelain tube 320 .

[0083] Specifically, the power cable 100 is inserted into the porcelain tube 320 while the tip of the cable conductor 110 is fixed to the tip side of the porcelain tube 320 by the conductor fixing metal fitting 240. At this time, the shield part 340 is arranged on the inner periphery of the porcelain tube 320 so as to electrically shield the region from the tip side of the cable conductor 110 to a part of the cable insulating layer 130. Also, at this time, the abutting part 640 of the stopper 600 is engaged with the rear end side of the shield part 340.

[0084] (S40: Pressing process) After the porcelain tube insertion step S30 is completed, the insulating tube 400 is pressed by the pressing mechanism 500 as shown in FIG.

[0085] Specifically, the position of the pressing mechanism 500 is moved toward the tip end of the power cable 100, and the stud bolt 560 of the pressing mechanism 500 is fixed to the flange portion 360 at the rear end of the porcelain tube 320. After the pressing mechanism 500 is fixed, the rear end side of the axial direction of the insulating tube 400 is pressed by the pressing mechanism 500 so that the insulating tube 400 is in close contact with the inner circumferential surface of the porcelain tube 320, while the axial tip of the insulating tube 400 is brought into contact with the abutment portion 640 of the stopper 600.

[0086] (S50: Sealing process) After the pressing step S40 is completed, the gap between the protective cover 700 and the outer periphery of the power cable 100 is sealed with a sealing member at the rear end of the protective cover 700.

[0087] In this manner, the cable termination structure 10 of this embodiment is manufactured as shown in FIG.

[0088] (4) Effects of this embodiment According to this embodiment, one or more of the following effects are achieved.

[0089] (a) In this embodiment, the stopper 600 is configured to suppress shrinkage of the cable insulating layer 130 in a direction away from the tip of the cable conductor 110 along the central axis. For example, even if stress that causes the cable insulating layer 130 to shrink back occurs due to the release of tensile stress in the cable insulating layer 130 generated during the manufacturing process of the power cable 100 or the release of tensile stress in the cable insulating layer 130 after a heat cycle, the stopper 600 can restrict axial movement of the cable insulating layer 130. As a result, even if the length L from the tip surface of the cable insulating layer 130 to the tip of the insulating tube 400 is short, the tip surface of the cable insulating layer 130 can maintain a positional relationship located closer to the tip of the cable conductor 110 than the insulating tube 400. In other words, the generation of a gap between the tip surface of the cable insulating layer 130 and the stopper 600 can be suppressed. By suppressing the generation of such a gap, the tip of the insulating tube 400 can be prevented from entering the gap between the tip surface of the cable insulating layer 130 and the stopper 960. This makes it possible to maintain the insulating tube 400 in close contact with the outer periphery of the power cable 100. As a result, the insulating properties of the cable termination structure 10 can be stably maintained.

[0090] (b) In this embodiment, the biting portion 620 of the stopper 600 is configured to bite radially inward from the outer periphery of the exposed cable insulating layer 130. The abutting portion 640 is engaged with the rear end of the shield portion 340 and configured to restrict movement of the biting portion 620 in a direction away from the front end of the cable conductor 110 between the rear end of the shield portion 340 and the axial front end of the insulating tube 400 when the abutting portion 640 is in contact with the rear end of the shield portion 340. In this manner, restricting the axial movement of the biting portion 620 by the abutting portion 640 can stably suppress shrink-back of the cable insulating layer 130. As a result, it is possible to reliably suppress the occurrence of a gap between the front end surface of the cable insulating layer 130 and the stopper 600.

[0091] (c) In this embodiment, the biting portion 620 is configured in a ring shape so as to surround the outer periphery of the cable insulating layer 130, and has an inner diameter smaller than the outer diameter of the cable insulating layer 130. This allows the biting portion 620 to be inserted into the groove portion 138 of the cable insulating layer 130 and fitted into the groove portion 138.

[0092] Furthermore, since the ring-shaped biting portion 620 bites into the entire outer periphery of the cable insulating layer 130, shrink-back of the cable insulating layer 130 can be suppressed in a well-balanced manner.

[0093] (d) In this embodiment, the abutment portion 640 of the stopper 600 has a rear end surface 644b with which the axial tip end surface of the insulating tube 400 comes into surface contact. This allows the insulating tube 400 to be pressed against the stopper 600 without biasing the stress that occurs when the insulating tube 400 abuts against the stopper 600. By suppressing bias in the stress applied to the stopper 600 in this way, the stopper 600 can suppress shrink-back of the cable insulating layer 130 in a balanced manner and can stably suppress the insulating tube 400 from entering the gap around the stopper 600.

[0094] <Second embodiment of the present invention> Next, a second embodiment of the present invention will be described. Only elements different from the above embodiment will be described below, and elements that are substantially the same as those described in the above embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0095] In the first embodiment described above, the biting portion 620 of the stopper 600 is ring-shaped, but the present disclosure is not limited to this. As in the present embodiment described below, a biting portion 620 different from that in the first embodiment may be employed.

[0096] A cable termination structure 10 according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a schematic cross-sectional view showing an enlarged portion of the cable termination structure according to this embodiment.

[0097] 7 , in this embodiment, the biting portion 620 of the stopper 600 is configured as, for example, a male screw, and is screwed radially inward from the outer periphery of the exposed cable insulating layer 130. Examples of the male screw include a screw or a bolt having a head 622. The head 622 of the biting portion 620 protrudes outward beyond the outer periphery of the cable insulating layer 130.

[0098] The contact portion 640 of the stopper 600 is configured to restrict movement of the head portion 622 of the biting portion 620 in a direction away from the tip of the cable conductor 110, for example.

[0099] In the accessory arrangement step S20 of this embodiment, after the pressing mechanism 500 is attached, the power cable 100 is passed through the insulating tube 400, and the insulating tube 400 is retracted to the rear end side of the final arrangement.

[0100] Next, the ring-shaped contact portion 640 of the stopper 600 is passed through the power cable 100, and the contact portion 640 is retracted toward the rear end side from the final position.

[0101] After the insulating tube 400 and the abutting portion 640 are retracted, a screw hole is formed radially inward from the outer periphery of the exposed cable insulating layer 130. The biting portion 620 as a male screw of the stopper 600 is screwed into the screw hole.

[0102] After the biting portion 620 is screwed in, the positions of the abutting portion 640 and the insulating tube 400 are readjusted. At this time, the abutting portion 640 is positioned so that it will be locked to the rear end side of the shield portion 340 in a subsequent process, and the axial tip of the insulating tube 400 is in abutment against the abutting portion 640, while restricting movement of the head portion 622 of the biting portion 620.

[0103] The formation of the screw holes in the outer periphery of the cable insulating layer 130 and the screwing of the biting portion 620 may be performed at any timing as long as the final positional relationship between the biting portion 620 and the abutting portion 640 described above can be achieved.

[0104] [Effects of this embodiment] (a) In this embodiment, the biting portion 620 serving as a male screw of the stopper 600 is screwed radially inward from the outer periphery of the exposed cable insulating layer 130, thereby allowing the biting portion 620 to firmly bite into the cable insulating layer 130. This improves the positional stability of the biting portion 620 of the stopper 600.

[0105] (b) In this embodiment, the biting portion 620 is a male thread, so that it is possible to use, for example, a commercially available bolt, thereby reducing the cost of the stopper 600.

[0106] Third Embodiment of the Present Invention Next, a third embodiment of the present invention will be described. As with the second embodiment, the description will be omitted as appropriate.

[0107] In the first embodiment described above, the stopper 600 has the biting portion 620 and the abutting portion 640, but the present disclosure is not limited to this. As in the present embodiment described below, a stopper 600 different from that of the first embodiment may be employed.

[0108] The cable termination structure 10 according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a schematic cross-sectional view showing an enlarged portion of the cable termination structure according to this embodiment.

[0109] 8, the stopper 600 of this embodiment functions as both the biting portion 620 and the abutting portion 640 of the stopper 600 of the first embodiment. That is, the stopper 600 is configured to be engaged with the rear end side of the shield portion 340, to be abutted by the axial tip of the insulating tube 400, and to be able to bite into the cable insulating layer 130 from the outer periphery toward the inside in the radial direction.

[0110] Specifically, the stopper 600 is configured, for example, in a ring shape and has a reduced diameter portion 660. The reduced diameter portion 660 is configured, for example, in a doughnut plate shape and extends radially inward of the stopper 600. The inner diameter of the reduced diameter portion 660 is smaller than the outer diameter of the cable insulating layer 130. With this configuration, the reduced diameter portion 660 can be inserted into the groove portion 138 of the cable insulating layer 130 and fitted into the groove portion 138.

[0111] In this embodiment, a cross section of one side of the central axis of stopper 600 is configured, for example, in an L shape, and reduced diameter portion 660 is provided on the rear end side of stopper 600. Note that reduced diameter portion 660 may also be provided at an intermediate position in the axial direction of stopper 600.

[0112] In this embodiment, from the viewpoint of fitting the stopper 600 from the outside of the power cable 100, it is preferable that the stopper 600 is divided into multiple parts on either side of a cross section including the central axis of the stopper 600, and it is more preferable that the stopper 600 is divided into halves.

[0113] In the accessory component placement process S20 of this embodiment, after cutting a groove 138 on the outer periphery of the cable insulating layer 130, the reduced diameter portion 660 of the halved stopper 600 is fitted into the groove 138 on the outer periphery of the cable insulating layer 130.

[0114] Thereafter, the position of the insulating tube 400 is adjusted as appropriate. At this time, the axial tip of the insulating tube 400 is in contact with the stopper 600.

[0115] [Effects of this embodiment] (a) In this embodiment, the stopper 600 serves three purposes: to engage with the shield portion 340, to abut against the insulating tube 400, and to bite into the cable insulating layer 130. This allows the cost associated with the stopper 600 to be reduced.

[0116] (b) In this embodiment, the stopper 600 serves the three functions described above, which simplifies the accessory arrangement step S20. This allows the cable termination structure 10 to be manufactured easily and quickly.

[0117] <Other Embodiments of the Present Invention> Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the present invention.

[0118] In the above embodiment, the direction in which the cable termination connection structure 10 is attached to the GIS is not specified, but the attachment direction is not limited. That is, the cable termination connection structure 10 may be attached to the GIS in any of the vertical, horizontal, and diagonal directions.

[0119] In the above embodiment, the case where the conductor fastener 240 is connected to the tip of the shield part 340 has been described, but the present disclosure is not limited to this case. The shield part 340 and the adapter to which the conductor fastener 240 is connected may be configured as separate bodies.

[0120] In the first embodiment described above, the biting portion 620 is configured in a ring shape, but the present disclosure is not limited to this. The biting portion 620 only needs to bite into at least a part of the outer periphery of the cable insulating layer 130. Furthermore, a plurality of biting portions 620 may be provided and arranged at predetermined intervals along the outer periphery of the cable insulating layer 130.

[0121] In the third embodiment described above, the case where the reduced diameter portion 660 is configured in a doughnut plate shape has been described, but the present disclosure is not limited to this case. The reduced diameter portion 660 only needs to be embedded in at least a portion of the outer periphery of the cable insulating layer 130. Furthermore, a plurality of reduced diameter portions 660 may be provided, and they may be arranged at predetermined intervals in the circumferential direction of the stopper 600.

[0122] <Preferred embodiment of the present invention> Preferred embodiments of the present invention will be described below.

[0123] (Appendix 1) a power cable having a cable conductor, a cable insulating layer, and a cable outer semiconductive layer, the layers being stripped stepwise in this order in an axial direction of the cable conductor; a conductor fixing bracket to which the tip of the cable conductor is compression-connected; a porcelain tube through which the power cable is inserted while the tip of the cable conductor is fixed by the conductor fixing metal fitting; a shield portion provided on an inner periphery of the porcelain bushing and electrically shielding a region from a tip side of the exposed cable conductor to a part of the cable insulating layer; a stopper that surrounds the outer periphery of the cable insulating layer and is engaged with the rear end side of the shield portion; an insulating tube provided in the porcelain bushing so as to surround the outer periphery of the cable insulating layer and the cable outer semiconductive layer, and which reduces an electric field around the power cable; a pressing mechanism that presses a rear end side of the insulating tube in the axial direction so that the insulating tube is in close contact with the inner peripheral surface of the porcelain tube while abutting the front end of the insulating tube in the axial direction against the stopper; Equipped with The stopper is configured to suppress shrink-back, which is shrinkage of the cable insulation layer in a direction away from the tip of the cable conductor along the central axis. Cable termination structure.

[0124] (Appendix 2) The stopper is a biting portion that bites radially inward from the outer periphery of the exposed cable insulation layer; a contact portion that is engaged with the rear end side of the shield portion and that, in a state in which the axial front end of the insulating tube is in contact with the contact portion, restricts movement of the biting portion in a direction away from the front end of the cable conductor between the rear end of the shield portion and the front end of the insulating tube in the axial direction; have 2. A cable termination structure as described in Appendix 1.

[0125] (Appendix 3) The biting portion is formed in a ring shape so as to surround the outer periphery of the cable insulation layer, and has an inner diameter smaller than the outer diameter of the cable insulation layer. 1. A cable termination structure as described in Appendix 2.

[0126] (Appendix 4) The biting portion is divided into a plurality of portions across a cross section including the central axis of the biting portion. 4. A cable termination structure as described in Appendix 3.

[0127] (Appendix 5) The biting portion is configured as a male screw and is screwed radially inward from the outer periphery of the exposed cable insulation layer. 1. A cable termination structure as described in Appendix 2.

[0128] (Appendix 6) The stopper is engaged with the rear end side of the shield portion, and is configured to be able to be brought into contact with the axial tip of the insulating tube and to bite radially inward from the outer periphery of the cable insulating layer. 2. A cable termination structure as described in Appendix 1.

[0129] (Appendix 7) The stopper has a rear end surface with which the axial tip end surface of the insulating cylinder comes into surface contact. 7. A cable termination structure according to any one of claims 1 to 6.

[0130] (Appendix 8) The stopper is disposed so that a normal to the rear end surface coincides with the central axis of the porcelain tube. 8. A cable termination structure as described in Appendix 7.

[0131] (Appendix 9) A step of peeling a cable conductor, a cable insulating layer, and a cable outer semiconductive layer in an axial direction of the cable conductor in this order in a power cable having the cable conductor, the cable insulating layer, and a cable outer semiconductive layer; a step of arranging, on the power cable, accessory members including a conductor fixing metal fitting to which the tip of the cable conductor is compression-connected, an insulating tube that surrounds the outer periphery of the cable insulating layer and the cable outer semiconductive layer and relieves the electric field around the power cable 100, a stopper that surrounds the outer periphery of the cable insulating layer and against which the tip of the insulating tube in the axial direction abuts, and a pressing mechanism on the rear end side of the insulating tube; a step of inserting the power cable into a porcelain tube while fixing a tip end of the cable conductor with the conductor fixing metal fitting, arranging a shield portion on an inner periphery of the porcelain tube so as to electrically shield a region from a tip end side of the cable conductor to a part of the cable insulating layer, and engaging the stopper with a rear end of the shield portion; a step of pressing a rear end side of the insulating tube in the axial direction by the pressing mechanism so that the insulating tube is in close contact with the inner peripheral surface of the porcelain tube while abutting the front end of the insulating tube in the axial direction against the stopper; Equipped with In the step of arranging the accessory member, The stopper is arranged so as to suppress shrink-back of the cable insulation layer in a direction away from the tip of the cable conductor along the central axis. A method for manufacturing a cable termination structure. [Explanation of symbols]

[0132] 10 Cable termination structure 100 Power Cable 110 Cable conductor 130 Cable insulation layer 138 Groove 140 Cable outer semiconductive layer 150 Cable Metal Tube 160 Cable sheath 240 Conductor Fixing Metal Fittings 320 Pipe 340 Shield part 342 Locking surface 360 flange 400 Insulating tube 420 Insulator 440 Semiconductive layer 500 Pressing mechanism 520 Contact member 540 Shaft 542 Spring 560 stud bolt 570 Pressure Plate 600 Stopper 620 Cutting section 622 Head 634 Shield part 640 Contact part 642 Cylindrical part 644 Disc Section 644b Rear end surface 644f front 660 Reduced diameter part 700 Protective Cover

Claims

1. a power cable having a cable conductor, a cable insulating layer, and a cable outer semiconductive layer, the layers being stripped stepwise in this order in an axial direction of the cable conductor; a conductor fixing bracket to which the tip of the cable conductor is compression-connected; a porcelain tube through which the power cable is inserted while the tip of the cable conductor is fixed by the conductor fixing metal fitting; a shield portion provided on an inner periphery of the porcelain bushing and electrically shielding a region from a tip side of the exposed cable conductor to a part of the cable insulating layer; a stopper that surrounds the outer periphery of the cable insulating layer and is engaged with the rear end side of the shield portion; an insulating tube provided in the porcelain bushing so as to surround the outer periphery of the cable insulating layer and the cable outer semiconductive layer, and which reduces an electric field around the power cable; a pressing mechanism that presses a rear end side of the insulating tube in the axial direction so that the insulating tube is in close contact with the inner peripheral surface of the porcelain tube while abutting the front end of the insulating tube in the axial direction against the stopper; Equipped with The stopper is a biting portion that bites radially inward from the outer periphery of the exposed cable insulation layer; a contact portion that is engaged with the rear end side of the shield portion and that, in a state in which the axial front end of the insulating tube is in contact with the contact portion, restricts movement of the biting portion in a direction away from the front end of the cable conductor between the rear end of the shield portion and the front end of the insulating tube in the axial direction; and The cable insulating layer is configured to suppress shrink-back, which is shrinkage in a direction away from the tip of the cable conductor along the central axis. Cable termination structure.

2. The biting portion is formed in a ring shape so as to surround the outer periphery of the cable insulation layer, and has an inner diameter smaller than the outer diameter of the cable insulation layer. The cable termination structure according to claim 1 .

3. The biting portion is configured as a male screw and is screwed radially inward from the outer periphery of the exposed cable insulation layer. The cable termination structure according to claim 1 .

4. A power cable having a cable conductor, a cable insulating layer, and a cable outer semiconducting layer, which are peeled off stepwise in this order in the axial direction of the cable conductor; a conductor fixing bracket to which the tip of the cable conductor is compression-connected; a porcelain tube through which the power cable is inserted while the tip of the cable conductor is fixed by the conductor fixing metal fitting; a shield portion provided on an inner periphery of the porcelain bushing and electrically shielding a region from a tip side of the exposed cable conductor to a part of the cable insulating layer; a stopper that surrounds the outer periphery of the cable insulating layer and is engaged with the rear end side of the shield portion; an insulating tube provided in the porcelain bushing so as to surround the outer periphery of the cable insulating layer and the cable outer semiconductive layer, and which reduces an electric field around the power cable; a pressing mechanism that presses a rear end side of the insulating tube in the axial direction so that the insulating tube is in close contact with the inner peripheral surface of the porcelain tube while abutting the front end of the insulating tube in the axial direction against the stopper; Equipped with The stopper is configured to be engaged with the rear end side of the shield portion, to be abutted by the axial tip of the insulating tube, and to be able to bite into the cable insulating layer from the outer periphery toward the inside in the radial direction, and to suppress shrink-back, which is shrinkage of the cable insulating layer in a direction away from the tip of the cable conductor along the central axis. Cable termination structure.

5. The stopper has a rear end surface with which the axial tip end surface of the insulating cylinder comes into surface contact. The cable termination structure according to any one of claims 1 to 4.

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