JPS5854568B2 - Cable termination box with built-in lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a termination connection of a power cable connected to an overhead power transmission/distribution line.

FIGS. 1A and 1B are diagrams for explaining an example of connecting a conventional power transmission line and the terminal end of a power cable.

A three-phase, three-core electric cable 53 rises from below the steel tower 51 to the middle of the two-line steel tower 51, and its ends are separated for each phase line and installed on a suitable pedestal 54 provided on the steel tower 51. It is introduced into one end of the terminal connection box 55.

On the other hand, appropriate branch connections are made to each of the power transmission lines 52,
The branch line 56 is extended to the other end of the terminal junction box 55, and the introduced cable phase lines 53' and the branch line 56 are electrically connected to the overhead power transmission line by pressing a button in the terminal junction box. A connection is made with the end of the capeple.

On the other hand, as is well known, abnormal voltages can be applied to power transmission lines due to lightning or other causes on transmission line conductors or steel towers. may also be destroyed.

Each piece of equipment is equipped with a protective device.

In connection with the termination connection described above, a surge arrester is often connected to the power transmission line at the same time, but in many cases, as shown in Figure B, which is a side view of Figure A, the surge arrester 57 installed on the pedestal 54 is connected to the power transmission line at the same time. One end is connected to the branch line 56, and although not shown, the other end of the lightning arrester 57 is grounded.

As can be understood from the overall configuration explained above, the installation of these termination boxes and surge arresters is done at a location far from the ground, and many of the electrical connections to these termination boxes and surge arresters are also located at ground level. This work is performed separately from the terminal, and it takes a lot of time to install and connect termination boxes and lightning arresters for each phase.

In view of the above-mentioned conventional circumstances, the present invention proposes a power cable termination box connected to a power transmission line, which incorporates both a connection part for connecting the power transmission line and the end of the cable, and a lightning arrester. In particular, by incorporating a lightning arrester element using a sintered body mainly composed of zinc oxide into the termination box, it is intended to provide a termination box having multiple functions.

Embodiments of the present invention will be explained below.

FIG. 2 shows an embodiment of the termination box of the present invention.

4 is a connection part, an insulator tube that encloses the lightning arrester.

The upper part of the insulator pipe 4 is covered with a Dobe cover 2, and the Dobe cover 2
A conductor pull-out rod 1 is made to protrude upward from the top of the power transmission line, and is directly connected to a branch line of a power transmission line or a power transmission line, although not shown.

On the other hand, through a removable bottom plate (not shown) below the insulator tube 4, an appropriate length of the skin was stripped off, and a pre-molded insulator 11 was fitted to the part where the external conductive layer was partially exposed to provide electric field mitigation means. The tip of the cable 5 is introduced from below the insulator tube 4, and the cable portion held by the pre-molded insulator 11 is held by the seat 10 made of epoxy resin or the like fixed by the bottom plate. extends further upwards with the outer conductor removed, and is electrically connected to one end of the conductor pull-out rod 1.

The portion indicated by 8 or 9 is a hollow disk-shaped or plural cylindrical arrester element assembly.

The lightning arrester element assembly 8.9 is formed by stacking a plurality of lightning arrester elements, and is fixed by being pressed from above and below.

These lightning arrester assemblies 8 , 9 are arranged in an annular or annular distributed manner so as to surround the cable 5 passing through the center line of the insulator tube 4 , one end of this arrester assembly is connected to the low voltage electrode 12 , and the surge arrester assemblies 8 , 9 are arranged in an annular or annular distributed manner so as to surround the cable 5 passing through the center line of the insulator tube 4 . Connected to ground.

The other end is connected to a high-voltage electrode 7 for connecting a lightning arrester, and a lead wire 13 connected to the high-voltage electrode 7 for connecting a lightning arrester extends upward inside the insulator tube 4, and an upper connecting fitting 3 branches off from the conductor pull-out rod 1. is connected to form a lightning arrester.

During use, the insulator tube 4 is kept in a lubricated state and is filled with an insulating oil 6 such as silicone oil.

As explained above, in the present invention, the lightning arrester assembly is arranged around the cable end connection, so that the lightning arrester assembly is arranged around the cable end connection. This effect on the arrester element can be avoided by changing the concentric insulation spacing of the cable termination and the arrester assembly by concentrically arranging the cable termination and the arrester assembly.

By the way, a surge arrester using a sintered body of zinc oxide has extremely good voltage-current characteristics as a surge arrester characteristic, and there is no follow-on current to the ground voltage as in a surge arrester made of a sintered body of silicon carbide. It is well known that the series gap can be eliminated and the device itself can be made smaller.

In the present invention, a sintered body containing zinc oxide as a main component is used as a lightning arrester, but the characteristics of the sintered body and the functions of each device are as follows. In consideration of this, the equipment is housed in a single insulator tube as described above, and compared to the case where the equipment is separate, it is possible to significantly reduce the equipment configuration space and reduce the weight.

All of the third aspects of the present invention described above are used in a state filled with insulating oil or inert gas.

Although not shown, for the lightning arrester element assembly 8.9, a hollow doughnut-shaped insulating tube or insulating cylinder is made of FRP or epoxy resin with a bottom shape, the lightning arrester element is housed in this, and the lightning arrester element is housed in the bottom of the insulating tube or the insulating cylinder in the shape of a hollow donut. It is also possible to arrange this in the insulator tube 4 and fix it in the insulator tube 4 with a detachable bottom plate.

At this time, a hole is provided in the bottom plate at the bottom of the hole in the insulating tube director and seat 10, and when the hole is peeled off so that the lightning arrester element and the low voltage electrode can be inserted from below, the lightning arrester element can be installed. It is easy to remove, especially when performing a completion test using DC voltage.
It is also convenient for quick inspections.

[Brief explanation of the drawing]

FIGS. 1A and 1B are diagrams showing the connection between a conventional power transmission line and the terminal end of a power cable. FIG. 2 is a diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Conductor pull-out rod, 2... Soil cover, 3... Upper metal fitting, 4... Insulator pipe, 5... Electric cable, 6...
Filling oil, 7... High voltage electrode, 8.9... Lightning arrester element assembly, 10... Seat, 11... Pre-molded insulator, 12... Low voltage electrode, 13... Lead wire .

Claims (1)

[Scope of Claims] 1. In a power cable terminal connection box connected to an overhead power transmission/distribution line, a lightning arrester using a sintered body containing zinc oxide as a main component is installed in an annular shape around the cable in the insulator tube forming the connection box. A cable termination junction box with a built-in lightning arrester, characterized in that it is arranged in a lightning arrester built-in type. 2. The cable termination box with built-in lightning arrester according to claim 1, characterized in that a hollow disk-shaped sintered body is used in the insulator tube. 3 Claim 1, characterized in that a plurality of lightning arresters are arranged in an annular distributed manner around the cable within the insulator pipe.
Cable termination junction box with built-in lightning arrester as described in . 4. A cable termination and connection box with a built-in lightning arrester according to claim 1, characterized in that an insulating tube is used and a sintered body is housed in the tube so that the sintered body can be taken in and out.