Voltage detection terminal device for cable terminals of underground power distribution equipment

Abstract

To contact a voltage detection terminal in an outer case and to detect voltage even without inserting a hand by opening a bottom plate of the outer case or without forming an inlet hole in a hand hole, even when an underground power distribution device is lowered with the outer case in accordance with lower ground height of an underground device.SOLUTION: In an underground power distribution device in which a device direct connection type cable terminal 3 is connected below a switch 2 accommodated in a multi-circuit switch tower 1 and an existing voltage detection terminal part 4 provided in the device direct connection type cable terminal 3 is provided on a bottom plate of the multi-circuit switch tower 1 or lower, the other end of an insulated wire 6 having one end electrically connected to a voltage detection terminal of the existing voltage detection terminal part 4 is derived into the multi-circuit switch tower 1 and electrically connected to a voltage detection terminal of a new voltage detection terminal part 7 provided in the multi-circuit switch tower 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a voltage detection terminal device for a cable terminal of an underground cable that is raised from the ground and connected to an underground power distribution device such as a switch inside an outer box installed above ground. [Background technology]

[0002] In underground power distribution lines, underground cables are erected and connected to devices such as transformers and switches inside enclosures installed above ground to convert electricity from high voltage to low voltage and change the flow of electricity. Device direct connection cable terminals such as those shown in Figure 1 of Patent Document 1 are used to connect the cables to these underground power distribution devices.

[0003] When repairing or inspecting these ground equipment, the door of the outer box is opened, the cap of the voltage test terminal (A) located on the terminal of the direct-connection cable for the equipment located inside the outer box is opened, and a voltage tester is brought into contact with the voltage test terminal to detect the voltage.

[0004] However, in line with the recent trend toward the elimination of utility poles, there is a social need for underground power distribution equipment used by electric power companies to be lowered above ground.

[0005] Therefore, the height of the conventional outer box has been reduced, the existing underground power distribution equipment is housed inside the outer box, and the direct-connection cable terminal hanging down from the underground power distribution equipment is placed inside the handhole, thereby lowering the height of the outer box above ground. Therefore, as shown in Figure 6, the voltage detector terminal (A) provided on the direct-connection cable terminal is also located inside the handhole. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-36005 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] In this way, the voltage detection terminal provided on the device-direct-connection type cable terminal connected under the underground power distribution equipment inside the outer box is located inside the handhole below the bottom plate of the outer box, so it is difficult to detect voltage just by opening the door of the outer box, and it is necessary to remove the bottom plate and insert one's hand or to reach inside the handhole, which makes voltage detection work time-consuming. Furthermore, if the cable terminal inside the handhole is temporarily submerged, the voltage detection leaks, making voltage detection impossible.

[0008] Therefore, this invention was made with an eye on these problems, and aims to provide a voltage detection terminal device for the cable terminal of underground power distribution equipment that allows contact with the voltage detection terminal inside the outer box even when the underground power distribution equipment is lowered together with the outer box as the height above ground of such underground equipment is lowered, and that allows voltage detection without opening the bottom plate of the outer box and inserting one's hand or inserting a hole in the hand hole. [Means for solving the problem]

[0009] The invention of claim 1 is a voltage detection terminal device for the cable terminal of underground power distribution equipment, in which a direct-connection type cable terminal is connected under underground power distribution equipment stored in an outer box, and an existing voltage detection terminal provided on the direct-connection type cable terminal is provided below the bottom plate of the outer box, and one end of a shielded wire or insulated wire electrically connected to the existing voltage detection terminal is introduced into the outer box and electrically connected to a new voltage detection terminal provided in the outer box.

[0010] In addition, the invention of claim 2 is a voltage detection terminal device for a cable terminal of underground power distribution equipment described in claim 1, in which one end of the shielded wire or insulated wire is introduced into a voltage detection cap that is placed over the existing voltage detection terminal, and when the voltage detection cap is placed over the existing voltage detection terminal, one end of the shielded wire or insulated wire is electrically connected to the existing voltage detection terminal, and the other end of the shielded wire or insulated wire is electrically connected to the new voltage detection terminal.

[0011] In addition, the invention of claim 3 is a voltage detection terminal device for a cable terminal of an underground power distribution equipment described in claim 1 or 2, in which the connection portion between the existing voltage detection terminal and the shielded wire or insulated wire, or the joint portion between the voltage detection cap placed over the existing voltage detection terminal and the existing voltage detection terminal, and the shielded wire or insulated wire, are watertight. [Effects of the Invention]

[0012] According to the invention of claim 1, even if the outer box housing the underground power distribution equipment is lowered above ground level and the existing voltage detection terminal of the cable terminal of the underground power distribution equipment is lower than the bottom plate of the outer box, when voltage detection is performed, the worker can easily perform voltage detection while standing on the ground by opening the door of the outer box, as the newly installed voltage detection terminal is located inside the outer box, and voltage detection work can be performed quickly and reliably.

[0013] Furthermore, according to the invention of claim 2 in particular, by using the voltage detector terminal of an existing device direct connection type cable terminal and connecting one end of a newly installed shielded wire or insulated wire to a voltage detector cap and then covering the existing voltage detector terminal, the existing voltage detector terminal and the shielded wire or insulated wire are electrically connected, and furthermore, the new voltage detector terminal and the existing voltage detector terminal are electrically connected, so that the underground distribution equipment that has been used previously can be used as is, and it can be used by simply installing a new voltage detector terminal in the underground distribution equipment inside the outer box, which is economical. Therefore, by removing the voltage detector cap of the new voltage detector terminal, the worker can perform voltage detection work using the same procedure as before, which is convenient.

[0014] Furthermore, according to the invention of claim 3, even if the voltage detection terminal of the existing device direct connection type cable terminal is temporarily submerged in water in the handhole, the voltage detection cap and the shielded wire or insulated wire placed over the existing voltage detection terminal have a watertight structure, so the newly installed voltage detection terminal can be used for voltage detection without being affected by water. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view of a multi-circuit switch tower with a door removed, which is provided with a voltage detection terminal device for a cable terminal of an underground power distribution device according to a first embodiment of the present invention. [Figure 2]1 is a side cross-sectional view of a multi-circuit switch tower provided with a voltage detection terminal device for a cable terminal of an underground power distribution device according to a first embodiment of the present invention. [Figure 3] 1 is an enlarged cross-sectional view of an existing voltage detection terminal of a voltage detection terminal device at a cable terminal of an underground power distribution device according to a first embodiment of the present invention, with a voltage detection cap placed over the terminal. [Figure 4] 1 is an enlarged cross-sectional view of an existing voltage detector terminal of a voltage detector terminal device at a cable terminal of an underground power distribution device according to a first embodiment of the present invention, with a voltage detector cap removed from the terminal. [Figure 5] 1 is a vertical cross-sectional view of a state in which a voltage detection cap is placed over a newly installed voltage detection terminal of a voltage detection terminal device at a cable terminal of an underground power distribution device according to a first embodiment of the present invention. [Figure 6] FIG. 1 is a front view of a multi-circuit switch tower with the door open, showing the voltage detection terminal locations of the cable terminals of a conventional underground power distribution device. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Embodiment Example 1) A voltage detection terminal device A for a cable terminal of underground power distribution equipment according to a first embodiment of the present invention will be described with reference to FIGS.

[0017] The voltage detection terminal device A at the cable terminal of the underground power distribution equipment in this embodiment example 1 is installed across each switch 2 in the multi-circuit switch tower 1 and the equipment direct-connection type cable terminal 3 connected below it, as shown in Figures 1 and 2.

[0018] An existing voltage detection terminal section 4 is provided on the device direct connection type cable terminal 3, and the location where this existing voltage detection terminal section 4 is provided is inside a handhole 5 below the multi-circuit switch tower 1.

[0019] The other end of the insulated electric wire 6, one end of which is connected to this existing voltage detection terminal part 4, is introduced into the multi-circuit switch tower 1 by penetrating the bottom plate of the multi-circuit switch tower 1, extending to the front of the lower part of each switch 2, and connected to the newly installed voltage detection terminal part 7 at that point.

[0020] The existing voltage detector terminal portion 4 consists of a voltage detector terminal 10 and a voltage detector cap 11. As shown in Fig. 3, the outer periphery of the device direct connection type cable terminal 3 is covered with an insulating rubber layer 8 and a conductive rubber layer 9, and the insulating rubber layer 8 protrudes from one side of the conductive rubber layer 9 as a substantially cylindrical protrusion 8a. The voltage detector terminal 10 is provided with one end embedded in this substantially cylindrical protrusion 8a and the other end protruding to the outside. When a voltage is generated in the conductive portion 3a inside the device direct connection type cable terminal 3, an induced voltage is generated in the voltage detector terminal 10, and this voltage is used for voltage detection.

[0021] It is possible that the voltage may drop when introduced into the newly installed voltage detection terminal section 7. If the voltage drops below that for high-voltage voltage detection due to the characteristics of each type of terminal, it is possible to generate a voltage for low-voltage voltage detection by resistive voltage division and operate it as a low-voltage voltage detector.

[0022] An electric detector cap 11 is provided which covers the electric detector terminal 10 and is always fixed to the outer periphery of the approximately cylindrical protrusion 8a, and one end of the insulated electric wire 6 is introduced into this electric detector cap 11 and connected to a contact spring 12 inside the electric detector cap 11. When the electric detector cap 11 is placed over the electric detector terminal 10, the contact spring 12 presses against and comes into contact with the electric detector terminal 10, electrically connecting the insulated electric wire 6 and the electric detector terminal 10. When the electric detector cap 11 is removed from the approximately cylindrical protrusion 8a, the electric detector terminal 10 is exposed to the outside.

[0023] As shown in Figure 4, in this voltage detector cap 11, one end of the insulated electric wire 6 is introduced into a recess 13a in a cap body 13 made of insulating rubber, and is connected to the contact spring 12, one end of which is fixed in the recess 13a. The outer periphery of the cap body 13 is covered with a conductive rubber layer 14, and a handle 15 protrudes from one end. The part of the insulated electric wire 6 that enters the voltage detector cap 11 is shielded with a conductive heat-shrinkable tube 16. Waterproof tape 17 is also placed over that. This makes the connection between the insulated electric wire 6 and the voltage detector cap 11 watertight.

[0024] 5, the new voltage detector terminal portion 7 is made up of a new voltage detector terminal 18 and a new voltage detector cap 19. One end of the new voltage detector terminal 18 is embedded in a substantially cylindrical protrusion 20a of a terminal base 20 made of an insulating rubber layer, and the other end protrudes to the outside. The terminal base 20 has a recess 20b on the side opposite the substantially cylindrical protrusion 20a, and the other end of the insulated electric wire 6 is introduced into this recess 20b and electrically connected to the new voltage detector terminal 18.

[0025] The terminal base 20 is sealed by fitting a fitting 21 into the opening of the recess 20b, and furthermore, the terminal base 20 around the approximately cylindrical protrusion 20a is pressed by a press fitting 22 from the outside.

[0026] The new voltage detector cap 19 is made of conductive rubber like the voltage detector cap 11, covers the new voltage detector terminal 18, and is fitted onto the outer periphery of the approximately cylindrical projection 20a of the terminal base 20. A conductive rubber film 23 is provided on the outer periphery of the approximately cylindrical projection 20a, and the clamp 22 and voltage detector cap 19 are connected by a conductive member.

[0027] To detect the voltage at the equipment direct-connected cable terminal 3 of the switch 2 in this multi-circuit switch tower 1, open the door (not shown) of the multi-circuit switch tower 1, and you will find newly installed voltage detection terminal sections 7 at the bottom of many of the switches 2. When you remove the newly installed voltage detection cap 19, the newly installed voltage detection terminal 18 will appear, and you can use this newly installed voltage detection terminal 18 to perform voltage detection in the same way as before.

[0028] If a voltage is generated in the conductive part 3a in the device direct connection type cable terminal 3, a voltage is induced in the voltage detection terminal 10 of the existing voltage detection terminal part 4, and this voltage is applied to the newly installed voltage detection terminal 18 through the insulated electric wire 6.

[0029] The voltage detector cap 11 of the existing voltage detector terminal unit 4 and the new voltage detector cap 19 of the new voltage detector terminal unit 7 are almost the same in shape as the voltage detector caps that have been used conventionally, and can be immediately recognized as voltage detector caps when an operator performs voltage detection. Also, by removing the voltage detector cap 11 of the existing voltage detector terminal unit 4 and the new voltage detector cap 19 of the new voltage detector terminal unit 7, inspection of the voltage detector terminal 10 or the new voltage detector terminal 18 can be easily performed. Furthermore, the voltage detector cap of the existing cable end can be used as the voltage detector cap of the new voltage detector terminal unit 7 as is.

[0030] In the above-mentioned first embodiment, an example was shown in which the voltage detection terminal device A of the cable terminal of the underground power distribution equipment was used in the multi-circuit switch tower 1, but it can also be used in a transformer tower that houses a transformer other than the multi-circuit switch tower 1, or in other underground power distribution equipment. Also, although it is expressed as a multi-circuit switch tower 1, it may also be an outer box with a door that houses underground power distribution equipment.

[0031] Although the insulated electric wire 6 is used in the first embodiment, a shielded wire may be used instead. The watertight structure between the voltage detector cap 11 of the existing voltage detector terminal part 4 and the insulated electric wire 6 is not limited to that in the first embodiment, and any suitable watertight structure may be used. [Explanation of symbols]

[0032] A. Voltage detection terminal device for cable terminals of underground power distribution equipment 1 Multi-circuit switch tower 2 Switch switch 3 Device direct connection type cable terminal 3a Conductive part 4 Existing voltage detector terminal 5 Hand hole 6 Insulated wire 7 New voltage test terminal 8 insulating rubber layer 8a approximately cylindrical protrusion 9 Conductive rubber layer 10 Voltage detector terminal 11. Electrodetector cap 12. Contact spring 13 Cap body 13a Recess 14 Conductive rubber layer 15 Handle 16 Conductive heat shrink tubing 17 Waterproof tape 18 New voltage detector terminal 19 New voltage detector cap 20 terminal base 20a approximately cylindrical protrusion 20b recess 21 fitting body 22 Clamp 23 Conductive rubber film

Claims

1. In an underground power distribution device in which a direct-connection cable terminal is connected under the underground power distribution device housed in an outer box, and an existing voltage detection terminal provided on the direct-connection cable terminal is provided below the bottom plate of the outer box, A voltage detection terminal device for a cable terminal of underground power distribution equipment, characterized in that one end of a shielded wire or insulated wire electrically connected to the existing voltage detection terminal is introduced into the outer box and the other end is electrically connected to a new voltage detection terminal provided in the outer box.

2. 2. The voltage detection terminal device for a cable terminal of underground power distribution equipment according to claim 1, characterized in that one end of the shielded wire or insulated wire is introduced into a voltage detection cap that is placed over the existing voltage detection terminal, and when the voltage detection cap is placed over the existing voltage detection terminal, one end of the shielded wire or insulated wire is electrically connected to the existing voltage detection terminal, and the other end of the shielded wire or insulated wire is electrically connected to the new voltage detection terminal.

3. 3. The voltage detection terminal device for a cable terminal of underground power distribution equipment according to claim 1 or 2, characterized in that the connection portion between the existing voltage detection terminal and the shielded wire or the insulated wire, or the joint portion between the voltage detection cap placed on the existing voltage detection terminal and the existing voltage detection terminal, and the shielded wire or the insulated wire, have a watertight structure.

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