JP2009165293A - Shield layer edge trim insulation structure of prefabricated joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shield layer edge trim insulation structure of a prefabricated joint capable of obtaining higher impulse voltage characteristics by suppressing increase in length of an insulation tube for shield layer edge trim. <P>SOLUTION: A barrier tube 57 which extends to the inside of an insulation tube 45 from the inside of an end part embedding electrode 19A of an epoxy unit 11 through the inside of an adapter bracket 41, is integrally formed with an epoxy molded body 17 of the epoxy unit 11, at the end part on the insulation tube 45 side of the epoxy unit 11. A rubber insulation ring 59 having a near L shape in cross section is interposed between the adapter bracket 41 and the barrier tube 57 as well as between the adapter bracket 41 and the insulation tube 45. Between the outer peripheral surface at the tip part of the barrier tube 57 and the inner peripheral surface of the insulation tube 45, an insulation seal material 69 is so interposed as to clog the gap between them. The outer peripheral surface of the insulation tube 45 is made concave for a longer creepage path. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an insulating structure for cutting off the shielding layer of both cables in a prefabricated joint of a CV cable (crosslinked polyethylene insulated power cable).

  In the cross bond connecting portion of the power cable, an insulating cylinder that electrically insulates (cuts the edge) the shielding layer of both cables is provided. FIG. 6 shows a conventional prefab joint provided with an insulating cylinder for cutting off the shielding layer edge (see Non-Patent Document 1). In the figure, 1A and 1B are CV cables to be connected, 3A and 3B are conductors of the CV cable, 5A and 5B are insulators of the CV cable, 7A and 7B are external semiconductive layers of the CV cable, and 9 is a conductor. A connection sleeve, 11 is an epoxy unit, 13A and 13B are stress cones, and 15A and 15B are stress cone compression devices.

  The epoxy unit 11 includes a cylindrical epoxy molded body 17, end embedded electrodes 19 </ b> A and 19 </ b> B at both ends, and a central embedded electrode 21. Each of the stress cones 13A and 13B includes a conductive rubber portion 23 and an insulating rubber portion 25. As shown in FIG. 7, one stress cone compression device 15 </ b> A includes an intermediate flange 27, a tension bolt 29, a washer 31, a shaft 33, a compression spring 35, a push fitting 37, an insulating push pipe 39, and the like. The other stress cone compressing device 15B is the same as the one stress cone compressing device 15A except that the stress cone 13B is directly pushed in by the metal fitting 37 without using an insulating push pipe.

  As shown in FIG. 7, an adapter fitting 41 is fixed to one end embedded electrode 19 </ b> A of the epoxy unit 11 with a bolt 43. Between the adapter fitting 41 and the intermediate flange 27 of the stress cone compression device 15A, an insulating cylinder 45 for cutting off the shielding layer is disposed. One end of the insulating cylinder 45 is fixed to the adapter fitting 41 by a bolt 47, and the other end is fixed to the intermediate flange 27 by a bolt 49. Further, the inner flange 53 of the cable protection tube 51 is fixed to the intermediate flange 27 with bolts 55.

Furukawa Electric Time Report No. 84, July 2001, page 24, Fig. 19

  The impulse voltage characteristics between the shielding layers of both cables required for the prefab joint incorporating the insulating cylinder for cutting the shielding layer as described above are -50 kV 3 times for the domestic standard 275 kV class, -65 kV 3 times for the 500 kV class, and the overseas IEC standard. The 220 kV class is ± 95 kV, and the conventional shielding layer edge cutting insulating structure satisfies this required characteristic. However, when the voltage class exceeds 220 kV for overseas, high impulse voltage characteristics of ± 125 kV continuous 10 times for IEC standards 330 to 400 kV class and ± 145 kV continuous 10 times for 500 kV class are required. The structure cannot satisfy this required characteristic.

  In order to satisfy the high impulse voltage characteristics, it is most effective to lengthen the insulating cylinder. However, if the insulating cylinder is lengthened, the total length of the prefab joint is increased, and the customer's specification dimensions do not fit in the installation space. There is a problem of not conforming to

  An object of the present invention is to provide a prefabricated joint shielding layer edge-cut insulation that suppresses an increase in the length of an insulating cylinder and can obtain higher impulse voltage characteristics without drastically degrading installation space restrictions and customer specification dimensions. To provide a structure.

In the shielding layer edge-insulating structure as shown in FIG. 7, the conductive rubber portion 23, the intermediate flange 27, and the pressing bracket 37 of the stress cone 13A are at the same potential as the shielding layer of one cable 1A, and the adapter bracket 41 is connected to the other cable 1B. (See FIG. 6). For this reason, when a high impulse voltage is applied between the shielding layers of both cables,
(1) Between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion Q of the conductive rubber portion 23,
(2) Between the inner peripheral portion P of the adapter fitting 41 and the inner peripheral portion R of the intermediate flange 27,
(3) Between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion S of the push fitting 37,
(4) Between the head T of the bolt 47 that fixes the insulating cylinder 45 to the adapter fitting 41 and the outer peripheral portion U of the intermediate flange 27,
A flashover is likely to occur.

  Therefore, the shielding layer edge cutting insulation structure of the prefab joint according to the present invention includes an epoxy unit, an adapter fitting, an insulating cylinder for electrically cutting the shielding layer of both cables, a cable protection fitting, a stress cone, and a stress cone compression. In a prefab joint including an apparatus and an insulating push pipe, the end of the epoxy unit on the insulating tube side extends from the inside of the end embedded electrode to the inside of the insulating tube through the inside of the adapter fitting. The barrier cylinder portion is formed integrally with the epoxy molded body of the epoxy unit (Claim 1).

  In the insulating structure for cutting off the edge of the shielding layer according to the present invention, between the adapter fitting and the barrier tube portion, and between the adapter fitting and the insulation tube, the cylindrical portion fitted inside the adapter fitting and the adapter fitting It is preferable to interpose an insulating ring having a substantially L-shaped cross section integrally formed with a flange that contacts the inner peripheral portion of the end surface on the insulating cylinder side.

  It is preferable that the insulating ring has a convex portion that fits into a counterbore hole for bolt head storage formed on the adapter fitting on the surface of the flange on the adapter fitting side.

  In the insulating structure for cutting off the shielding layer according to the present invention, it is preferable that an insulating sealing material is interposed between the outer peripheral surface of the tip of the barrier cylinder and the insulating cylinder.

  Further, in the shielding layer edge-cut insulating structure according to the present invention, it is preferable to interpose an insulating putty material between the outer peripheral surface of the intermediate portion of the barrier tube portion, the insulating tube, and the insulating ring ( Claim 5).

  Further, in the shielding layer edge-cut insulating structure according to the present invention, the insulating rubber packing is softer than the O-ring interposed between the adapter fitting and the insulating cylinder between the flange portion of the insulating ring and the insulating cylinder. It is preferable to interpose (claim 6).

  Moreover, in the shielding layer edge cutting insulating structure according to the present invention, the outer diameter of the end portion of the insulating push pipe on the stress cone compression device side is equal to or larger than the outer diameter of the press fitting of the stress cone compression device, It is preferable that the outer diameter of the intermediate portion of the insulated push pipe is made smaller than the outer diameter of the metal fitting to form an annular protrusion on the stress cone compression device side of the outer peripheral surface of the insulated push pipe.

  Further, in the shielding layer edge-insulating insulation structure according to the present invention, the outer diameter of both end portions of the insulating cylinder is made larger than the outer diameter of the adapter fitting and the flange portion of the end portion of the cable protection fitting, It is preferable that the outer diameter be smaller than the outer diameters at both ends.

  According to the first aspect of the present invention, since the barrier cylinder portion is formed, it becomes difficult for the flash between (1) PQ to occur, so that the impulse voltage characteristics can be improved.

  According to the invention of claim 2, since the insulation of the inner peripheral portion P of the adapter bracket can be reinforced by interposing the insulating ring having a substantially L-shaped cross section, (1) between PQ and (2) It is difficult for a flash to occur between PR and (3) PS, and the impulse voltage characteristics can be further improved.

  According to the invention of claim 3, since the projection of the adapter ring is provided on the flange portion of the insulating ring, the insulation of the bolt head in the counterbore hole is reinforced. (1) A flash between PQ, (2) PR, and (3) PS is less likely to occur, and impulse voltage characteristics can be further improved.

  According to the invention of claim 4, since the insulating seal material is interposed between the outer peripheral surface of the tip of the barrier cylinder and the insulating cylinder, the gap in that part can be eliminated. A flash between PQ, (2) PR, and (3) PS is less likely to occur, and the impulse voltage characteristics can be further improved.

  According to the invention of claim 5, the insulating putty material is interposed between the outer peripheral surface of the intermediate portion of the barrier tube portion, the insulating tube, and the insulating ring, thereby eliminating the gap at that portion. Therefore, the flashing between (1) PQ, (2) PR, and (3) PS is less likely to occur, and the impulse voltage characteristics can be further improved. .

  According to the invention of claim 6, since the insulating rubber packing is interposed between the flange portion of the insulating ring and the insulating cylinder, the gap in that portion can be eliminated. -Q, (2) PR, and (3) PS are less likely to cause flashing, and the impulse voltage characteristics can be further improved.

  According to a seventh aspect of the present invention, the outer diameter of the end portion of the insulating push pipe on the stress cone compression device side is equal to or larger than the outer diameter of the press fitting of the stress cone compression device. By forming the annular protrusion on the stress cone compression device side of the outer peripheral surface of (3), it becomes difficult for the flashing between (3) PS to occur, and the impulse voltage characteristics can be further improved.

  According to the invention of claim 8, the outer diameter of both ends of the insulating cylinder is made larger than the outer diameter of the adapter fitting and the flange of the end of the cable protection fitting, and the outer diameter of the intermediate portion is set to the both ends. Since the creepage distance outside the insulating cylinder can be increased without increasing the overall length of the insulating cylinder by making it smaller than the outer diameter of (4), it becomes difficult for the flash between the TUs to occur, and the impulse voltage characteristics Can be further improved.

  1 and 2 show an embodiment of the present invention. 1 and 2, the same reference numerals as those in FIGS. 6 and 7 are assigned to the same or corresponding parts as those in FIGS. 6 and 7 described above. This prefab joint also has an epoxy unit 11, an adapter fitting 41, an insulating cylinder 45 that electrically cuts the shielding layer of both cables, a cable protection fitting 51, a stress cone 13A, and a stress cone compression device 15A, as in the prior art. And an insulating push pipe 39.

  This embodiment is different from the prior art in that a barrier cylinder 57 is integrally formed with the epoxy molded body 17 of the epoxy unit 11 at the end of the epoxy unit 11 on the insulating cylinder 45 side. The barrier cylinder 57 extends from the inside of the end embedded electrode 19 </ b> A of the epoxy unit 11 to the inside of the insulating cylinder 45 through the inside of the adapter fitting 41. The insulating cylinder 45 has an inner diameter on the adapter fitting 41 side larger than an inner diameter on the stress cone compression device 15A side so that the distal end side of the barrier cylinder portion 57 can be inserted inside.

  With this configuration, due to the presence of the barrier cylinder portion 57, (1) it becomes difficult for a flash to occur between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion Q of the conductive rubber portion 23, and the impulse voltage characteristic is improved. Can be improved.

  A rubber insulating ring 59 having a substantially L-shaped cross section is interposed between the adapter fitting 41 and the barrier cylinder portion 57 and between the adapter fitting 41 and the insulating cylinder 45. As shown in FIG. 3, the insulating ring 59 has a flange portion 63 integrally formed at one end of the cylindrical portion 61, and a circular convex portion 65 at a predetermined interval in the circumferential direction on the surface of the flange portion 63 on the cylindrical portion 61 side. Are provided integrally. As shown in FIG. 2, the cylindrical portion 61 is a portion that fits inside the adapter fitting 41, and the collar portion 63 is a portion that abuts the inner peripheral portion of the end surface of the adapter fitting 41 on the insulating cylinder 45 side, and is circular. The convex portion 65 is a portion that is fitted into a counterbore 67 for accommodating the bolt head portion formed in the adapter fitting 41.

  With such a configuration, due to the presence of the insulating ring 59, (1) between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion Q of the conductive rubber portion 23, and (2) between the inner peripheral portion P and the intermediate portion P of the adapter fitting 41. Between the inner peripheral portion R of the flange 27 and (3) it becomes difficult for a flash to occur between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion S of the push fitting 37, and the impulse voltage characteristics can be further improved. .

  In addition, as shown in FIG. 4, it is preferable to form the annular convex part 68 in the internal peripheral surface at the side of the collar part 63 of the cylindrical part 61 of the insulating ring 59. FIG. Further, as shown in FIG. 5, it is more preferable that the annular convex portion 68 is formed so as to protrude from the end surface of the flange portion 63. When such an annular convex portion 68 is formed, a gap between the barrier cylinder portion 57, the insulating ring 59, and the insulating cylinder 45 can be eliminated.

  Further, an insulating seal material 69 is interposed between the outer peripheral surface of the distal end portion of the barrier cylinder portion 57 and the inner peripheral surface of the insulating cylinder 45 so as to close a gap between them. The insulating seal material 69 is provided by winding a sealing tape around the outer periphery of the tip of the barrier cylinder 57 when the prefab joint is assembled.

  With such a configuration, the gap between the barrier cylinder 57 and the insulating cylinder 45 can be eliminated. (1) Between the inner peripheral part P of the adapter fitting 41 and the outer peripheral part Q of the conductive rubber part 23, (2 ) Between the inner peripheral part P of the adapter fitting 41 and the inner peripheral part R of the intermediate flange 27, and (3) It becomes difficult for a flashing to occur between the inner peripheral part P of the adapter fitting 41 and the outer peripheral part S of the pusher fitting 37. Impulse voltage characteristics can be further improved.

  Further, an insulating putty material 71 is interposed between the outer peripheral surface of the intermediate portion of the barrier tube portion 57 and the insulating tube 45 and between the insulating ring 59 so as to close the gap between them. The insulating putty material 71 is also provided by wrapping a putty tape around the outer periphery of the intermediate portion of the barrier tube portion 57 during assembly of the prefab joint.

  With such a configuration, it is possible to eliminate the gap between the barrier cylinder portion 57 and the insulating cylinder 45 and between the barrier cylinder portion 57 and the insulating ring 59. (1) The inner peripheral portion P of the adapter fitting 41 and the conductive rubber portion 23, (2) between the inner peripheral portion P of the adapter fitting 41 and the inner peripheral portion R of the intermediate flange 27, and (3) the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion S of the push fitting 37. It is difficult to generate a flash between the two, and the impulse voltage characteristics can be further improved.

  Further, an insulating rubber packing 73 is interposed between the flange 63 of the insulating ring 59 and the insulating cylinder 45. The insulating rubber packing 73 is formed of a softer rubber than the O-ring 75 interposed between the adapter fitting 41 and the insulating cylinder 45 and is crushed before the O-ring 75 by tightening the bolt 47 to generate a surface pressure. It is like that. In this way, the airtightness of the O-ring 75 is not impaired.

  With this configuration, the gap between the flange 63 of the insulating ring 59 and the end surface of the insulating cylinder 45 can be eliminated. (1) The inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion Q of the conductive rubber portion 23 (2) between the inner peripheral portion P of the adapter fitting 41 and the inner peripheral portion R of the intermediate flange 27, and (3) a flash between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion S of the pressing fitting 37. Is less likely to occur, and the impulse voltage characteristics can be further improved.

  Further, the outer diameter of the end portion of the insulating push pipe 39 on the stress cone compression device 15 side is set to be equal to or larger than the outer diameter of the press fitting 37 of the stress cone compression device 15, and at the intermediate portion of the insulating push pipe 39. An annular protrusion 77 is formed on the outer peripheral surface of the insulating push pipe 39 on the stress cone compression device 15 side by making the outer diameter smaller than the outer diameter of the press fitting 37.

  With such a configuration, due to the presence of the annular protrusion 77, (3) it is difficult for a flash to occur between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion S of the push fitting 37, and the impulse voltage characteristics are further improved. Can be made.

  The insulating cylinder 45 has an outer diameter at both ends larger than an outer diameter of the adapter fitting 41 and an outer diameter of the flange portion 53 at the end of the cable protection fitting 51, and an outer diameter of the intermediate portion at an outer diameter of both ends. The outer peripheral surface of the insulating cylinder 45 is made concave, and the creeping distance is increased. In addition, an insulating anticorrosion tube 79 is put on the outer periphery from the adapter fitting 41 to the insulating cylinder 45 and the flange portion 53. This prevents the head T of the bolt 47 that fixes the insulating tube 45 to the adapter fitting 41 from being exposed to the outside.

  With such a configuration, the creepage distance of the outer peripheral surface of the insulating cylinder 45 is increased, and the head T of the bolt 55 is covered with the anticorrosion tube 79. (4) The head T of the bolt 47 and the cable protection fitting 53 It is difficult for a flash to occur between the outer peripheral portions U, and the impulse voltage characteristics can be further improved.

  In this embodiment, the conventionally used intermediate flange 27 (see FIG. 7) is omitted, and the flange portion 53 of the cable protection fitting 51 is directly fixed to the insulating cylinder 45 by the bolt 55. The tension bolt 29 of the stress cone compression device 15A is also directly fixed to the insulating cylinder 45. According to the above-described configuration, even if the intermediate flange 27 is present, it is difficult for a flash to occur between the inner peripheral portion P of the adapter fitting 41 and the outer peripheral portion S of the push fitting 37. However, if the intermediate flange 27 is omitted. , PS becomes less likely to occur between PS.

Sectional drawing which shows one Embodiment of the shielding layer edge cutting insulation structure of the prefabricated joint which concerns on this invention. The principal part expanded sectional view of the shielding layer edge cutting insulation structure of FIG. FIG. 4A is a cross-sectional view illustrating an example of an insulating ring used in the shielding layer edge-cut insulating structure in FIG. 1, and FIG. (A) which shows the other example of the insulation ring used for the shielding layer edge cutting insulation structure of FIG. 1 is sectional drawing, (B) is a rear view. FIG. 4A is a cross-sectional view and FIG. 4B is a rear view illustrating still another example of an insulating ring used in the insulating structure for cutting off the shielding layer of FIG. Sectional drawing which shows the conventional prefab joint including a shielding layer edge cutting insulation structure. Sectional drawing which shows the shielding layer edge cutting insulation structure of the conventional prefab joint.

Explanation of symbols

1A, 1B: CV cable 3A, 3B: Conductor 5A, 5B: Insulator 7A, 7B: External semiconductive layer 11: Epoxy unit 13A, 13B: Stress cone 15A, 15B: Stress cone compression device 17: Epoxy molded body 19A 19B: End embedded electrode 23: Conductive rubber portion 25: Insulating rubber portion 35: Compression spring 37: Push fitting 39: Insulating push pipe 41: Adapter fitting 45: Insulating tube 47: Bolt 51: Cable protection fitting 53: Flange portion 55: Bolt 57: Barrier cylinder part 59: Insulating ring 61: Cylindrical part 63: Gutter part 65: Circular convex part 67: Counterbore part 69: Insulating sealing material 71: Insulating putty material 73: Rubber packing 75: O-ring 77: Annular projection 79: anticorrosion tube

Claims (9)

In a prefab joint comprising an epoxy unit, an adapter bracket, an insulating cylinder that electrically cuts the shielding layer of both cables, a cable protection bracket, a stress cone, a stress cone compression device, and an insulated push pipe,
A barrier cylinder portion extending from the inner side of the end embedded electrode to the inner side of the insulating cylinder at the end of the epoxy unit on the insulating cylinder side is integrated with the epoxy molded body of the epoxy unit. The insulating structure for cutting off the shielding layer of the prefab joint, characterized in that it is formed as described above.   Between the adapter fitting and the barrier tube portion and between the adapter fitting and the insulating tube, a cylindrical portion fitted inside the adapter fitting and an inner peripheral portion of the end surface of the adapter fitting on the insulating tube side are brought into contact. 2. The insulating structure for cutting off the shielding layer of a prefab joint according to claim 1, wherein an insulating ring having a substantially L-shaped cross section integrally formed with the flange portion is interposed.   The said insulating ring has the convex part fitted in the counterbore hole for bolt head accommodation formed in the adapter metal fitting in the surface at the side of the adapter metal fitting of a collar part. Insulation structure for the prefabricated joint of the shielding layer.   The insulating structure for cutting off the shielding layer of the prefab joint according to any one of claims 1 to 3, wherein an insulating sealing material is interposed between the outer peripheral surface of the front end portion of the barrier tube portion and the insulating tube.   The prefab according to any one of claims 1 to 4, wherein an insulating putty material is interposed between the outer peripheral surface of the intermediate portion of the barrier tube portion, the insulating tube, and the insulating ring. Insulation structure that cuts off the shielding layer of the joint.   6. An insulating rubber packing softer than an O-ring interposed between the adapter fitting and the insulating tube is interposed between the flange portion of the insulating ring and the insulating tube. The insulating structure for cutting off the shielding layer of the prefab joint according to any one of the above.   The outer diameter of the end portion on the stress cone compression device side of the insulated push pipe is equal to or larger than the outer diameter of the push fitting of the stress cone compression device, and the outer diameter of the intermediate portion of the insulated push pipe is made of the push fitting. 7. An insulating structure for cutting off the edge of a shielding layer of a prefab joint according to claim 1, wherein an annular projection is formed on the outer peripheral surface of the insulating push pipe on the stress cone compression device side. .   The outer diameter of both ends of the insulating cylinder is larger than the outer diameter of the adapter bracket and the flange portion at the end of the cable protection bracket, and the outer diameter of the intermediate portion is smaller than the outer diameter of both ends. An insulating structure for cutting off the shielding layer of the prefab joint according to any one of claims 1 to 7.   The shielding layer edge cutting insulating structure of a prefab joint according to any one of claims 1 to 7, wherein the intermediate flange is omitted and the bolt and tension bolt of the cable protection metal fitting are directly fixed to the insulating cylinder.

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