JP2526842Y2 - Direct-buried low-pressure branching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to an underground direct buried branch device used for underground power distribution of a low-voltage power cable.

[Problems to be solved by conventional technologies and ideas] Underground power distribution has been promoted for distribution systems of 6kV or more, but in recent years, underground power distribution systems have spread to low-voltage distribution lines of 600V or less. It is getting. As this low-voltage underground distribution system, the 6.6 kV underground line from the distribution substation is pulled down into a pad-mounted transformer installed on the road and stepped down,
Further, it is branched by a low-voltage branching device and connected to a drop-in power cable line of each customer. Although this low-pressure branching device is sometimes installed on the road, the efficiency of use of the road surface is impaired. Therefore, the low-pressure branching device is often installed in a handhole provided under the road.

Underground power distribution cable pipelines are usually buried so that the upper end is located about 60 cm below the road surface, and for this purpose a trench with a cross section of about 100 cm is excavated. Handholes (mostly prefabricated handholes are used recently) have dimensions of 100cm in length, width and height, and even if prefabricated handholes are used, The excavation width and excavation depth need to be further increased by about 50 to 80 cm compared to the channel ditches. However, when attempting to excavate deeper than a channel culvert, it is often the case that excavation is hindered by existing buried objects such as gas and water. Also, the road occupied by the road during construction is increased due to the wider excavation width.

In addition, the above excavation is usually performed manually by hand from the viewpoint of preventing damage to existing buried objects.
The large excavation area and depth are also problematic in terms of labor and time associated with excavation.

In addition, the installation of low-pressure branching equipment, such as the conventional need to route cables in narrow handholes,
There was also a problem in terms of assembly workability.

The present invention has been made in view of the above-mentioned problems, and the underground burial is hardly hindered by existing buried objects under the road, the area occupied by the road during construction is small, and the excavation for underground installation is difficult. An object of the present invention is to provide an underground installation low-pressure branching device capable of reducing labor and time, further greatly simplifying installation and assembly work at the installation location of the device, and improving workability. .

[Means for Solving the Problems] The direct buried low-pressure branching device of the present invention that achieves the above object is as follows.
A protective case having an openable and closable lid at the upper opening and directly buried in the ground, first and second trunk connection lines housed in the protective case and having one end drawn out of the protective case; A connection line for branching, and two connection changeover switches accommodated in the protective case, wherein the first and second trunk line connection lines are respectively connected to the branch connection line via the connection changeover switch. It has a movable plug that is connected and slides up and down so that the connection changeover switch can be opened and closed through an upper opening of the protective case, and has a waterproof seal portion that seals a sliding portion of the movable plug. It is characterized by the following.

[Operation] The direct-buried low-pressure branching device of the present invention has the above-described configuration and is directly buried under the road, so that it is not necessary to construct a handhole. Also, the device inside the protective case can be made compact, and the size of the protective case can be reduced. Therefore, the digging area and digging depth required for installing the low-pressure branching device of the present invention under the road under the road may be at most as large as the culvert for constructing the pipe groove, and when constructing the conventional handhole. It is significantly reduced in comparison. Therefore, according to the present invention, the underground installation of the low-pressure branching device is hardly hindered by the existing buried object, the road occupation area under construction is small, and
The labor and time of excavation for underground installation can be reduced.

Also, in the present invention, all the devices required for branching are housed in the protective case and the necessary connecting lines are drawn out of the protective case, and these can be assembled in the factory in advance. In this case, it is only necessary to bury a protective case containing a low-voltage branching device and connect the connecting lines drawn from the protective case to the trunk line or the branch line, respectively, which greatly simplifies installation and assembly work at the installation site. .

Further, in the direct buried low-voltage branching device of the present invention, the first and second trunk connection lines are connected to the branch connection line via the connection changeover switch. Thereby, the connection between the first trunk line and the branch line and the connection between the second trunk line and the branch line can be opened and closed independently of each other.

Therefore, for example, when an accident occurs in the transformer connected to the first trunk line and supplying power, the branching line and the first line are connected.
The connection with the main trunk connection line can be released, and power can be received from another transformer via the second trunk connection line. As a result, the power outage time can be shortened, and the problem of underground power distribution, which takes time to recover from an accident, can also be solved.

Since the opening and closing operation of the connection changeover switch is performed by moving the movable plug up and down which can be operated from the upper opening of the protective case, the operation is easy, and the waterproof seal of the sliding portion of the movable plug is easily formed. it can.

[Example] The present invention will be described in detail based on an illustrated example.

The drawings show an embodiment of the direct buried type low-pressure branching device according to the present invention. FIG. 1 is a plan view and FIG. 2 is a sectional view. In the branch body 1 made of an elastic and electrically insulating material such as rubber, two hollow cylindrical connection changeover switches 1b are provided so as to be connected to a hollow cylindrical branch 1a having a sealed bottom. ing. Annular conductor connectors 1c are respectively built in the inner peripheral portions of the branch portion 1a and the two connection changeover switch portions 1b, and these conductor connectors 1c are integrally connected. Further, annular conductor connectors 1d are respectively built in the inner peripheral portions on the bottom side of the two connection changeover switches 1b. A connection portion of the current limiting fuse 2 is inserted into the branch portion 1a so as to be freely inserted into and removed from the conductor connector 1c. 4
Is connected. On the other hand, a movable plug 5 that can be manually moved up and down is fitted in the hollow portion of the connection changeover switch unit 1b, and the movable plug 5 includes a conductor 5a, an insulating portion 5b having electrical insulation, and an insulating portion 5b. Grip on top of
5c, when the movable plug 5 is completely pushed into the connection changeover switch 1b, the conductor 5a comes into close contact with the conductor connectors 1c and 1d. Further, the movable plug 5 is sealed by a sealing material 6, and the connection changeover switch portion 1b has a watertight structure. Further, the two conductor connectors 1d are connected to separate trunk connection lines 7, respectively.

The branching device main body configured as described above is housed in a protective case 8 having a branch connection hole 8a indicated by a dotted line and two main line connection holes 8b at a lower portion. And the branch connection hole
A branch connecting line 4 is drawn out from the main line connecting hole 8b and a main line connecting line 7 is drawn out from the main line connecting hole 8b by being sealed with a waterproof packing 9. A flange 10 is attached to an outer surface of each of the connection holes 8a and 8b, and each of the connection lines 4 and 7 is connected to a branch cable and a trunk line cable via connectors (not shown). The upper opening of the protective case 8 is covered with a lid 8c which can be freely opened and closed.
The top surface of 8c almost coincides with the ground level.

The low-voltage underground power distribution using the direct-built low-voltage branch device having such a configuration will be described. First, the low-voltage branch device of the present invention in which the above-described low-voltage branch device main body is built in the protective case 8 in advance in a factory or the like. Is manufactured, and the states of the two movable plugs 5 are set according to the purpose of use. For example, when the left movable plug 5 is pulled up as shown by the dotted line, the left main connecting line 7 and the branch connecting line 4 are cut off, and conversely, the left movable plug 5 When pushed in as shown by the solid line, the left main connecting line 7 and the branch connecting line 4 are connected. This is the same for the movable plug 5 on the right side. Therefore, when different transformers are connected to the left and right trunk connection lines 7, the power source supplied to the branch connection line 4, ie, the transformer, Can be selected.

When such a branching device is used, even if the transformer selected and connected by the movable plug 5 has an abnormality for some reason and is in a power failure state, the currently pushed movable plug 5 is pulled up. By pushing in another movable plug 5 that has been pulled up, power can be supplied from another transformer to the branch connection line 4, so that the power outage time can be shortened. In addition, left and right trunk connection line 7
If a transformer is connected to only one side of the device and the movable plug 5 is used while both are pushed in, the device can be used as a normal T-branch connection device.

In addition, since the current limiting fuse 2 is installed between the branch part 1a and the branch connecting line 4, if an abnormality occurs on the branch cable side, that is, on the customer side, the current limiting fuse 2 is turned off. Only with this, the fuse of the transformer connected to the trunk connecting line 7 connected to the branch side does not change, so that the range of power failure can be minimized.

In constructing an underground distribution line using the direct buried low-voltage branching device of the present invention, the direct buried branching device and the trunk line of the present invention should be connected to the pad-mounted transformer installed on the road. And excavating ditches on roads to embed branch pipes. Then, while laying a pipeline in the excavated culvert, the direct-buried low-pressure branching device of the present invention is placed together with the protective case 8 at a predetermined position in the culvert, and the branching connection line 4 and the inside of the conduit are connected. Connect the branch cable with the connector. Also,
The trunk connection lines 7 at the left and right ends are connected in the same way as the output cables of the different transformers installed on the road,
Alternatively, as described above, only one of them is connected to the transformer to form a branch from the main line. When this connection work is completed, the pipeline and the direct-buried low-voltage branching device are backfilled to complete the construction of the low-voltage underground distribution line. That is, in the present invention, since the branching device is previously housed integrally in the protective case 8, only the protective case 8 is buried at the work site, so that a fine installation work is hardly required and the work efficiency is improved.

[Effects of the Invention] As described above, according to the present invention, the construction of a handhole is not required, and the excavation for underground installation may be at most as large as the culvert for constructing a cable conduit. Therefore, as compared with the related art, the underground installation is less hindered by the existing buried object, the area occupied by the road during construction is small, and the labor and time for excavation can be reduced.

Further, according to the present invention, at the installation site, the entire protection case is directly buried in the excavated ditch, and the connection line drawn from the protection case only needs to be connected to the main line or the branch line. Construction and work are significantly simplified and the construction time is shortened.

Furthermore, in the direct buried type low-voltage branching device of the present invention, when an accident occurs in the transformer being supplied with power, the operation of the two connection changeover switches in the present invention device makes it easy to receive power from another transformer. Since switching can be performed, there is an effect that the power outage time at the time of an accident can be shortened.

The operation of the connection changeover switch as described above can be easily performed by vertically sliding the grip portion of the movable plug from the opening at the top of the protective case, and it is also easy to seal the movable plug in a watertight manner. There is an advantage that is.

[Brief description of the drawings]

1 is a plan view and FIG. 2 is a cross-sectional view of one embodiment of a direct-buried low-pressure branching device according to the present invention. Reference numeral 1 is a branch body, 1a is a branch portion, 1b is a connection changeover switch portion, 1c and 1d are conductor connectors, 2 is a current limiting fuse, 3 is a connector, 4 is a branch connecting line, 5 is a movable plug, 5a Is the conductor,
5b is an insulating part, 7 is a connecting line for a main line, and 8 is a protective case.

Continuing on the front page (72) Inventor Kenichi Ando 1008, Niibori, Kumagaya-shi, Saitama Mitsubishi Electric Works, Ltd. Inside the factory (56) References JP-A-57-156605 (JP, A) Jikken Sho 51-24537 (JP, Y1)

Claims (1)

(57) [Scope of request for utility model registration] 1. A protective case having an openable and closable lid at an upper opening portion and directly buried in the ground, and first and second housings accommodated in the protective case and having one end drawn out of the protective case. The first and second connecting switches, each of which is provided with a main connecting line and a branch connecting line, and two connection changeover switches housed in the protective case;
And a second main line connecting line is connected to the branch connecting line via the connection changeover switch, respectively, and the connection changeover switch is slid up and down so as to be able to open and close through an upper opening of the protection case. A direct-buried low-pressure branching device having a movable plug and a waterproof seal portion for sealing a sliding portion of the movable plug.