JP5142124B2 - Terminal connection box for coaxial CV cable and supporting structure thereof - Google Patents

Description

  The present invention relates to a termination junction box for a coaxial CV cable (cross-linked polyethylene insulated power cable) and a support structure thereof.

  A coaxial CV cable has a main conductor made of a copper twisted wire at the center, an external conductor is provided on the outside via a main insulator made of crosslinked polyethylene, and lead is put on the outside via an external insulator made of polyethylene or the like. It has a structure in which a cover is provided and an anticorrosion layer made of polyethylene or the like is provided on the outside (see Patent Document 1). The outer conductor is formed by concentrically twisting a large number of copper wires. The outer conductor serves as a return conductor for passing a return current.

  The terminal junction box for the coaxial CV cable includes a soot tube having a conductor lead bar connected to the main conductor of the coax CV cable at the upper end, and the external conductor of the coaxial CV cable is drawn out of the soot tube to the outside of the joint box. It has a structure in which an external conductor lead terminal is provided. In the conventional terminal junction box of this type, as shown in Patent Document 2, the outer conductor lead-out terminal is attached to the lower metal fitting of the steel pipe, so that the lower metal fitting of the steel pipe has the same potential as the outer conductor of the coaxial CV cable. Therefore, the lower bracket of the soot tube cannot be directly fixed to the gantry (ground potential).

  Therefore, conventionally, a structure in which the lower part of the insulating cylinder is fixed on the gantry as in Patent Document 2, or a plurality of supporting insulators are set up on the gantry as in Patent Document 3, and the supporting insulator is electrically insulated from the gantry. The structure which fixes the lower metal fitting of a soot pipe on the top is adopted.

Japanese Patent Laid-Open No. 11-12083 JP-A-8-126181 JP 2000-261948 A

  However, in the structure in which the lower part of the insulating cylinder is fixed on the gantry as in Patent Document 2, the voltage of the main conductor is applied to the upper portion of the soot tube, and the voltage of the outer conductor is generated in the metal fitting directly below (upper part of the insulating cylinder) In particular, when the transmission voltage becomes high, the electrical burden on the soot pipe becomes large. Moreover, since the soot tube, the outer conductor lead-out portion, and the insulating cylinder are formed on the gantry, the height is increased. Further, the insulating cylinder must be able to withstand the weight of the soot tube and the outer conductor lead-out portion. Providing the insulating cylinder in this way increases the cost when the voltage becomes high and the soot tube becomes large.

  On the other hand, in a structure in which a plurality of support insulators are set up on a stand and the lower metal fitting of the steel pipe is fixed on the support insulator, when the transmission voltage is further increased and the size of the steel pipe is increased, the steel pipe is stably supported. It is difficult. For example, in a termination junction box (hereinafter referred to as an aerial termination junction box) installed outdoors (in the atmosphere), the height of the soot pipe used for an AC 30 kV class coaxial CV cable is about 1.3 m. If so, it is possible to stably support the soot tube with four support insulators. However, in the air termination connection box of DC 250kV class coaxial CV cable which is currently being put into practical use as a DC submarine cable system, the height of the soot pipe is 5.4m. If it is supported by the support lever set up above, a very strong and large-sized support lever is required, and it cannot be handled by a general-purpose support lever. In addition, support insulators that support large steel pipes are subject to the weight of the steel pipe itself, including accessories and attachments, as well as strong bending stress, compression and tensile stress (hereinafter referred to as loads) due to strong winds and earthquakes. Therefore, the support insulator may be damaged. In addition, in a high voltage class such as a DC 250 kV class, an appropriate general-purpose support insulator that can maintain electrical insulation and can withstand the above-described load is not available at present.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a termination connection box for a coaxial CV cable that has a structure that stably supports a large sized pipe on a pedestal without using a support insulator and does not apply a voltage to the pedestal, and a support structure thereof. There is to do.

To achieve the above object, coaxial CV cable terminal connection box according to the present invention, have a conductor lead rod main conductor of the coaxial CV cable is connected to the upper end, the ceiling of the terminal connection box support table at the lower end a porcelain tube which have a lower bracket which is fixed a tubular cable protection fitting is fixed to the outside of the coaxial CV cable in the ground potential, a tubular assembly for connecting the lower bracket and cable protection bracket of the porcelain bushing With three-dimensional
The cylindrical assembly includes an upper insulating cylinder connected to a lower metal fitting of the vertical pipe, a lower insulating cylinder connected to an upper end of the cable protection metal, and an intermediate connecting the upper insulating cylinder and the lower insulating cylinder. An outer conductor lead terminal to which an outer conductor of a coaxial CV cable is connected is provided in a part of the intermediate metal tube.

  A coaxial CV cable termination connection box supporting structure according to the present invention includes the coaxial CV cable termination connection box described above and a pedestal at a ground potential that supports the termination connection box. The portion below the lower metal fitting of the soot tube is positioned in the gantry, and the lower metal fitting of the soot tube is fixed to the gantry to be supported by the gantry.

  In the support structure for the termination connection box for the coaxial CV cable according to the present invention, an insulated wire drawn out of the gantry is connected to the outer conductor lead terminal of the termination junction box, and the insulation is connected to the gantry. It is preferable that an opening for securing a separation distance necessary for insulation is provided between the electric wires.

According to the present invention, since the lower metal fitting and the outer conductor lead terminal of the end connection box for the coaxial CV cable are insulated by the upper insulating cylinder, it is possible to directly fix the lower metal fitting to the frame at the ground potential. This makes it possible to support the soot tube firmly and stably on the gantry, and eliminates the need for a support insulator for supporting the soot tube, thereby reducing the cost. Further, the cost can be reduced by making the upper and lower insulating cylinders have the same structure.
In addition, the upper and lower insulating cylinders can be applied by electrical or / and mechanical design with respect to the target termination connection box for the coaxial CV cable.

  FIG. 1 shows an embodiment of a termination connection box for coaxial CV cables according to the present invention. In the figure, 11 is a coaxial CV cable that has been subjected to a predetermined process such as stripping the end, 13 is a main conductor of the coaxial CV cable 11, 15 is a main insulator, and 17 is coaxial with the main conductor. An external conductor (return conductor), 19 is an external insulator (return insulator), 21 is a lead coat, and 23 is an anticorrosion layer (coat). The inner and outer peripheral surfaces of the main insulator 15 and the outer insulator 19 are provided with an inner semiconductive layer and an outer semiconductive layer, respectively, but are not shown for simplicity. The structure of the coaxial CV cable is not limited to this. For example, the size of the main conductor, the size of the outer conductor, the number, the arrangement, the way of providing the semiconductive layer, and the like can be arbitrarily determined by electrical design or the like.

  Reference numeral 25 denotes a termination connection box that accommodates a processing section that has undergone predetermined processing such as stripping of the coaxial CV cable 11, 27 denotes a porcelain soot pipe that constitutes a main insulator of the termination connection box 25, and 29 denotes an upper fitting of the soot pipe 27. , 31 is a lower metal fitting of the soot tube 27. A conductor lead bar 33 connected to the main conductor 13 of the coaxial CV cable 11 is provided at the upper end of the soot tube 27 so as to penetrate the upper metal fitting 29 vertically. The lower metal fitting 31 of the soot tube 27 includes a large-diameter cylindrical portion 31a coupled to the lower end of the soot tube 27, a flange portion 31b provided so as to project from the bottom plate portion of the large-diameter tubular portion 31a, and the bottom plate portion. It is comprised from the small diameter cylinder part 31c provided so that it might protrude below from. A capacitor cone 35 is attached to the outer periphery of the cable main insulator 15 in the soot tube 27. Reference numeral 37 denotes a support member for the capacitor cone 35.

  On the other hand, a cylindrical cable protection fitting 39 is fixed to the anticorrosion layer 23 of the coaxial CV cable 11. 41 is a waterproofing processing part by tape winding. The cable protection fitting 39 is electrically connected to the cable lead sheath 21 and is at ground potential. The cable protection fitting 39 and the lower fitting 31 of the soot tube 27 are connected by a cylindrical assembly 43.

  The cylindrical assembly 43 includes an upper insulating cylinder 45 connected to the lower end of the small diameter cylindrical portion 31c, a lower insulating cylinder 47 connected to the upper end of the cable protection fitting 39, and the upper insulating cylinder 45 and the lower insulating cylinder. The intermediate metal tube 49 is further divided into a first metal tube 49a, a second metal tube 49b, and a third metal tube 49c in order from the top. . The upper insulating cylinder 45 and / or the lower insulating cylinder 47 may have a structure in which pleated protrusions are provided on the outer periphery as disclosed in Patent Document 2.

  Between the lower end flange portion of the first metal cylinder 49a and the upper end flange portion of the second metal cylinder 49b, the flange portion of the oil stopper metal fitting 51 is sandwiched. In addition, an annular plate portion 55 formed integrally with the outer conductor lead terminal 53 is sandwiched between the lower end flange portion of the second metal cylinder 49b and the upper end flange portion of the third metal cylinder 49c. The internal space above the seal fitting 51 is filled with insulating oil 57, and the internal space below the seal fitting 51 is filled with insulating compound 59.

  As shown in FIG. 2, the outer conductor lead terminal 53 is formed so as to protrude in the radial direction from a part of the outer periphery of the annular plate portion 55. The annular plate portion 55 is formed in such a size that its inner peripheral side protrudes inward from the inner peripheral surfaces of the second metal cylinder 49b and the third metal cylinder 49c, and a large number of screws are provided on the inner peripheral side protruding portion. A hole 61 is formed. A bolt hole 63 for fixing the annular plate portion 55 between the lower end flange portion of the second metal tube 49b and the upper end flange portion of the third metal tube 49c is formed in the outer peripheral portion of the annular plate portion 55. Further, the outer conductor lead terminal 53 is formed with a bolt hole 65 for connecting a terminal of a lead insulated wire to be described later. The external conductor lead-out terminal 53 and the external conductor 17 of the cable are electrically connected by screwing a terminal (not shown) attached to the end of the strand of the external conductor 17 into the screw hole 61. . Note that a plurality of external conductor lead terminals 53 may be provided on the annular plate portion 55. For example, if the external conductor lead terminals 53 are arranged at an angle of 90 degrees, they can be taken out from four directions. Further, it may be connected to two or more external conductor lead terminals. Further, the outer conductor lead terminal 53 may not be integrated with the annular plate portion 55 but may be attached by bolting or welding.

  As is apparent from the above configuration, the terminal connection box 25 has the lower metal shell 31 and the outer conductor lead terminal 53 insulated from each other by the upper insulating cylinder 45, so that the lower metal shell 31 is directly connected to the ground potential. It is possible to fix it to the gantry.

FIG. 3 shows a support structure for the terminal junction box 25. The mount 67 that supports the terminal junction box 25 is in the form of a tower that is assembled from steel or the like. The gantry 67 is installed on the concrete foundation 69 and is at ground potential. The terminal connection box 25 has a portion below the lower metal fitting 31 of the soot tube 27 positioned in the gantry 67 and fixes the lower metal fitting 31 of the soot tube to the ceiling portion 71 of the gantry 67 via the pedestal 73, thereby It is supported vertically above. The tub tube 27 may be directly fixed to the gantry 67 without the pedestal 73. Furthermore, you may provide the structure which fixes the tub tube 27 like the base 73 in the arbitrary positions of the ceiling part 71. FIG.
Further, the gantry 67 may be installed directly on the ground. Further, a predetermined portion of the coaxial CV cable 11 located below the pedestal 67 may be inserted by digging down the ground, and may be further inserted or / and embedded in a duct or a side groove.

  A terminal 77 attached to an end portion of the insulated wire 75 is connected to the outer conductor lead terminal 53 of the termination connection box 25. The insulated wire 75 is drawn out of the gantry 67 through an opening 79 provided in the gantry 67. The frame 81 around the opening 79 is formed in a size that secures a separation distance necessary for insulation between the frame 81 and the insulated wire 75.

  The opening 79 may be an arbitrary polygon including a triangle or a circle. Moreover, you may hold | grip and / or fix with insulators, such as an insulator, in the position which ensures the separation distance required for insulation so that the insulated wire 75 may not shake by a strong wind. Further, the insulated wire 75 may be rod-shaped, plate-shaped, or cylindrical (including pipe). Furthermore, since the insulated wire 75 has only to be inserted through the center point of the frame 81 by arranging the frame 81 so as to be inserted perpendicularly to the horizontal angle of the insulated wire 75, it is necessary for insulation from the frame 81. A separation distance can be easily secured. Further, an insulating cover may be attached to an arbitrary position of the frame body 81 or the whole, or the frame body 81 itself may be made of an insulating material so that the separation distance can be easily secured.

In FIG. 1 and FIG. 3, the cylindrical assembly 43 is disposed substantially vertically, but may be bent between the upper insulating cylinder 45 and the lower insulating cylinder 47. Further, the upper insulating cylinder 45 and the conductor lead terminal 53 may be bent. This makes it possible to facilitate installation space and installation of coaxial cables. Further, in FIG. 3, the insulated wire 75 is shown substantially horizontal to the ground. However, since the insulated wire 75 can be pulled out with an inclination by bending the cylindrical assembly 43, it can be inserted substantially vertically into the inclined frame body 81. Since the insulated wire 75 has only to pass through the center point of the frame body 81, a separation distance necessary for insulation from the frame body 81 can be easily secured.
Note that the entire tubular assembly 43 may be inclined, and further, for example, the tubular assembly 43 may be arranged substantially horizontally by bending from above the upper insulating tube 45.

  In FIG. 3, equipment and the like disposed around the insulated wire 75 connected from the terminal connection box for the coaxial CV cable are omitted. For example, the insulated wire 75 is directly connected to the equipment. Fixed to the relay insulator and connected to the device. The equipment and configuration can be freely designed, such as being connected to a cable termination connection box connected to the equipment.

  Moreover, it is good also as the mount frame 67 which inclines the soot pipe 27 of FIG. Alternatively, for example, the top and bottom of FIG. 3 may be turned upside down. For example, the vertical pipe 27 may be suspended from a portal steel structure and fixed, and the coaxial CV cable may be arranged from above. The frame body 81 may also be provided at an arbitrary position of the gate-type steel structure.

Furthermore, the coaxial CV cable termination junction box and its supporting structure in FIG. 3 are arranged in a structure filled with an inert gas or an insulating gas (for example, SF ₆ ) or the like (“in gas”). In other words, when the lower part of the tub tube 27 or the gantry 67 is connected to and / or fixed to a structure, equipment, or the like so as to have a ground potential, the coaxial CV cable termination junction box according to the present invention and its support Can be applied with structure. For example, when the gantry 67 is fixed to the structure in the configuration as shown in FIG. 3, the coaxial CV cable is inserted from the lower part of the structure (naturally, a necessary portion is subjected to an airtight process). In addition, the various embodiments described above can be applied to the arrangement in the structure filled with such an arbitrary gas.

The half incision front view which shows one Embodiment of the termination | terminus connection box for coaxial CV cables which concerns on this invention. FIG. 3 is a plan view of an outer conductor lead terminal used in the termination junction box of FIG. 1. The support structure of the termination | terminus junction box of FIG. 1 is shown, (A) is a front view, (B) is a side view of the principal part.

Explanation of symbols

11: Coaxial CV cable 13: Main conductor 15: Main insulator 17: External conductor 19: External insulator 21: Lead insulator 23: Corrosion-proof layer 25: Termination connection box 27: Steel pipe 29: Upper metal fitting 31: Lower metal fitting 33: Conductor Lead bar 35: capacitor cone 39: cable protection fitting 43: cylindrical assembly 45: upper insulation tube 47: lower insulation tube 49: intermediate metal tube 51: seal fitting 53: outer conductor lead terminal 67: stand 75: insulated wire 77 : Terminal

Claims (4)

Upper main conductor of the coaxial CV cable have a connected conductor pull bar in a porcelain tube to have a lower bracket which is fixed to the ceiling portion of the terminal connection box support table at the lower end, it is fixed to the outside of the coaxial CV cable A cylindrical cable protection bracket that is at ground potential, and a cylindrical assembly that connects between the lower bracket of the steel pipe and the cable protection bracket,
The cylindrical assembly includes an upper insulating cylinder connected to a lower metal fitting of the vertical pipe, a lower insulating cylinder connected to an upper end of the cable protection metal, and an intermediate connecting the upper insulating cylinder and the lower insulating cylinder. An end connection box for a coaxial CV cable, comprising an outer conductor lead terminal to which an outer conductor of a coaxial CV cable is connected. The intermediate metal cylinder is divided into upper and lower parts, and an annular plate part is sandwiched between them. The annular plate part is integrally provided with the outer conductor lead-out terminal, and the inner peripheral side has an inner side of the intermediate metal cylinder. An inner peripheral side projecting portion is formed on the inner peripheral side projecting portion. Holes to which the strands of the outer conductor of the coaxial CV cable are connected are provided at intervals in the circumferential direction. The terminal junction box for coaxial CV cables according to claim 1. A terminal connection box for a coaxial CV cable according to claim 1 or 2 , and a frame at a ground potential that supports the terminal connection box, wherein the terminal box has a portion below a lower metal fitting of the vertical pipe as the frame. A support structure for a terminal connection box for a coaxial CV cable, which is supported by a frame by fixing the lower metal fitting of the soot tube to the ceiling of the frame. An insulated wire drawn out of the gantry is connected to the outer conductor lead terminal of the termination connection box, and the gantry is provided with an opening for ensuring a separation distance necessary for insulation between the insulated wire and the gantry. The support structure for a terminal junction box for a coaxial CV cable according to claim 3 , wherein

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