JPH06208811A - T-shape bushing - Google Patents

Abstract

PURPOSE:To facilitate disconnection of an apparatus in a box body, and to omit adjustment at the time of mounting by providing a disconnection rod in a hollow shaft, and by embedding a fixed side contact part, to/from which the front end of the disconnection rod is attached/detached, in the front end of an insulating layer on the other side of a center conductor. CONSTITUTION:A through hole 2a is formed at the shaft core of the inside of a center conductor 2 embedded in an insulating layer 1 to a recessed part 2d3. A round-rod shape disconnection rod 11, on which a female screw 11a is formed, is inserted in the hole 2a, and a groove 19 is formed in parallel to the shaft on the under surface of the large diameter part of the rod 11. A groove 12a is formed on the recessed part 2d3, while a disconnection rod fixing tool 12, on which a male screw is formed, is loosely fitted in the recessed part 2d3, and the male screw part is fitted with the female screw 11a of the rod 11. A seat 15 is preliminarily embedded in the left end of the insulating layer 1, while a multi-contact 16 of the same shape as a multi-contact 17 fitted in the inner circumference of the conductor 2, is fitted in the inner circumference of the seat 15, which is fixed to the rear surface of a conductor 39 provided vertically on an apparatus chamber in the front surface side of a partition plate 31e.

Description

Detailed Description of the Invention

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a T-type bushing used for a cable connecting portion such as a gas-insulated switchgear.

[0003]

2. Description of the Related Art FIG. 6 shows an example of a right side view of a conventional gas-insulated switchgear to which a T-shaped bushing is attached. In the figure, the box 31 has a door 31 on the left side in the figure, which is the front side.
a is provided, and a door 31b is provided on the right side in the figure, which is the rear side. Inside the box 31, a partition 31c is placed near the center.
However, a partition 31e is provided vertically toward the rear of the center,
A partition 31d is provided laterally at the lower end of each of the partitions 31c and 31e, and a sulfur hexafluoride gas (hereinafter referred to as SF6 gas) is enclosed in the interior surrounded by the partitions 31c, 31d and 31e. It is an airtight container.

On the other hand, in front of the upper portion of the partition 31e, a partition 31g having an upper end fixed to a ceiling plate 31f is vertically installed. A partition 31b is provided between the lower end of the partition 31g and the rear surface of the partition 31c.
As a result, the box body 31 is divided into a low pressure chamber 32A at the front of the partition 31c, an equipment chamber 32B at the rear of the partition 31c, and a partition.
It is divided into a cable chamber 32C at the rear of 31e and a disconnector chamber 32D at the lower center of the ceiling plate 31f. Of these, the low-pressure chamber 32
A has a disconnector operating mechanism 33a on the upper front surface of the partition 31c.
However, a circuit breaker operating mechanism 34a is mounted on the center front surface of the partition 31c, and a disconnecting switch operating mechanism 35a is mounted below the partition 31c via a mounting base.

Next, a T-shaped bushing 36A is airtightly provided at the center of the ceiling plate 31f by penetrating a round hole (not shown) provided in the ceiling plate 31f at the lower portion. A disconnector 33 with a ground blade is attached to the upper rear surface of the partition 31c,
The upper pole of the disconnector 33 is connected to the lower end of the T-shaped bushing 36A by a conductor, and the lower pole of the disconnector 33 is the partition 31b.
Is connected to the upper end of a bushing 31b ₁ which is vertically provided in the middle part of the.

A vacuum circuit breaker 34 is attached to the intermediate rear surface of the partition 31c, and the upper pole of the vacuum circuit breaker 34 is connected to the lower end of the bushing 31b ₁ above the vacuum circuit breaker.
The lower pole of 34 is connected to the upper terminal of a current transformer 37 mounted behind the vacuum circuit breaker 34. The lower terminal of the current transformer 37 has a disconnector with a grounding device attached to the lower rear surface of the partition 31c via an insulator 38 fixed to the box 31.
It is connected to the upper pole of the 35 and below the disconnector 35
A ground switch 38 is provided on the upper surface of 31d. Furthermore,
The lower pole of the disconnector 35 is connected to the front end of a conductor 39 bent in a substantially L shape, and the rear upper end of the conductor 39 is connected to the front end of a T-shaped bushing 36B attached to the upper end of the partition 31e, which will be described in detail later. Then, the electromotive insulator 5 is attached to the lower surface of the ceiling plate 31f behind the partition 31g.

On the other hand, at the lower end of the T-shaped bushing 36B, a high-voltage cross-linked polyethylene cable (hereinafter referred to as a cable) 40 rising from the floor on which the gas-insulated switchgear is installed is connected as described later in detail, and the ceiling board A cable (not shown) connected to an adjacent board (not shown) is also connected to the upper side of the T-shaped bushing 36A attached to 31f on the side orthogonal to the plane of FIG.

Next, FIG. 7 is an enlarged detailed view of a vertical cross section of the T-shaped bushing 36B. In the figure, a T-shaped bushing 36
B is a substantially T-shaped insulating layer 41 that is formed by casting with an epoxy resin and has an opening formed on the lower right side of the figure, and a substantially L-shaped central conductor 42 that is previously embedded in the insulating layer 41. When,
Blind plug part 43 which will be described later in detail and which is attached to the right side opening
And a cable connecting portion 44 that is inserted into the lower opening to hold the cable 40 and connect the core wire to the central conductor 42.

Of these, the left side of the insulating layer 41 is provided with a mounting surface 41b orthogonal to the central conductor 42 having an L-shaped cross section with a recess 41a formed on the outer periphery, and this mounting surface 41b is shown in the drawing. A metal pad with a female screw is embedded and is hermetically fixed to the rear surface of the partition 31e via a 0 ring 41c with a bolt (not shown).

The left end of the center conductor 42 is fixed to the conductor 39 with a bolt, and the right end of the center conductor 42 has a recess having a U-shaped cross section.
42d ₁ is formed, and a female screw hole 41d ₂ is provided at the bottom axis of the recess 42d ₁ . Similarly, the concave portion 42d ₂ and the female screw hole 41d are also formed in the cable connecting portion 44 at the lower end of the center conductor 42.
₂ are provided, and conical recesses 42d ₃ are formed at the bottoms of the female screw holes 41d ₂ and 42d ₂ , respectively.

Next, in the blind plug portion 43, a spacing tube 45 having a U-shaped cross section is loosely inserted in the recess 42d ₁ at the right end of the center conductor 42, and further to the right of this spacing tube 45 is a substantially truncated cone shape. Stress cones 46
Is inserted into the inner circumference of the insulating layer 41 in a pressed state by a pressing member described later. On the right side of the stress cone 46, a paddle 46a having a mountain-shaped cross section for electric field relaxation is previously embedded, and on the right side surface of the insulating layer 41, a lid 47 having a substantially convex cross section is fixed by a bolt. A pressing member 48 composed of a bolt 48a, a compression coil spring, and the like is previously attached to the inside of the.

On the other hand, the cable connecting portion 44 has a plurality of copper wedges on the outer periphery of the core wire at the tip of the cable 40 inserted therein.
44a is mounted, the under side of the wedge 44a is pressing tube 44b of schematic cross-sectional external thread is formed convex-shaped cylindrical is screwed to the female screw hole 41d ₂ on the outer circumferential upper half, the pressing tube 44b On the lower side of the cable, there is a cylindrical stress cone 49 with a mountain-shaped cross section.
It is inserted in 40 jackets.

Further, below the stress cone 49,
A tubular protection tube 50, which is not shown in detail, is inserted in advance, and inside the protection tube 50, a pressing member (not shown) including a coil spring, a bolt, and the like (not shown) is attached like the blind plug 43. . Similarly, the protection tube 50 is fixed by a bolt through a metal pad embedded in the lower end of the insulating layer 41 as shown by a dotted line, and as a result, the stress cone 49 is a pressing member inside the protection tube 50 and is upwardly shown in the figure. It is pressed. Therefore, in the T-shaped bushing 36B configured as described above, the cable 40 is connected to the disconnector 38 and the like inside the equipment room 32B via the conductor 39 through the central conductor 42 embedded in the insulating layer 41. Connected.

By the way, in the insulated switchgear as shown in FIG. 6, a withstand voltage test of the cable 40 arranged on the installation floor is performed at the time of new installation or expansion, and at that time, due to the capacitance between the ground and the ground. DC withstanding voltage test is adopted. On the other hand, in the insulated switchgear that has been operating for many years, the copper powder generated by turning on and off the disconnector 35 and the decomposition product of SF6 gas due to the arc generated by turning on and off the disconnector 35 are also disconnected. Deposit on the surface of the vessel. Then, if a withstand voltage test is performed on this insulated switchgear with direct current, it will be more severe than the application of an alternating voltage due to the induced polarization of the deteriorated insulator. Then, the equipment inside the box 31 is to be disconnected from the test power supply.

[0015]

However, in the T-shaped bushing 36B configured as shown in FIG. 7, if the cable for the withstand voltage test is removed by removing the stress cone 46 inside the blind plug part 43 or the like. If you connect it like part 44,
The DC voltage for testing is also applied to the disconnector 35 in the equipment room 32B via the center conductor 42 and the conductor 39.

Therefore, it is conceivable to remove the cable 44 connected to the cable connecting portion 44 and perform a withstand voltage test, but then the protective tube 50 must be removed and the stress cone 49, etc. must be removed. Takes. Therefore, an object of the present invention is to obtain a T-shaped bushing in which a device inside a box can be easily separated from an external connection cable during a withstand voltage test, and adjustment at the time of mounting is unnecessary. [Constitution of Invention]

[0017]

The present invention provides a T-shaped bushing in which a central conductor is embedded in a T-shaped insulating layer, and a cable connection portion is provided at one end of the central conductor. A hollow shaft is used on the other side, and a disconnecting rod is installed inside the hollow shaft so that the outer circumference is in contact with the hollow shaft and can move back and forth in the axial direction. By embedding the fixed-side contact part, it is not necessary to align the disconnecting rod and the fixed-side contacting part, and when disconnecting the cable, withdraw the disconnecting rod and disconnect the device connected to the other side of the center conductor. It is a T-shaped bushing that is capable of performing a withstand voltage test of the cable and is easy to assemble on the box side.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the T-shaped bushing of the present invention will be described below with reference to the drawings. However, the same parts as those in FIGS. In FIG. 1, the left end of the center conductor 2 buried inside the insulating layer 1 is the insulating layer 1.
Is located on the inner side of the left end, and a through hole 2a is formed in the inside of the shaft up to the right recess 2d ₃ . On the other hand, inside the through hole 2a, a round rod-shaped disconnecting rod 11 having a female thread 11a formed on the large diameter portion at the right end is inserted from the right side in FIG. Has a groove 19 formed parallel to the axis.

Further, the inner periphery of the through hole 2a of the center conductor 2 is
A pair of multi-contacts 17 made of adjacent bronze plates are locked in a groove (not shown) provided on the inner circumference of the through hole 2a, and a groove having a semicircular cross section is formed near the right end of the inner circumference of the through hole 2a. It is formed in an annular shape, and a C-shaped retaining ring 18 is inserted into this groove, and a key 20 is embedded from the groove into which the C-shaped retaining ring 18 is inserted to the right end. Further, in the recess 2d ₃ , a cylindrical disconnecting rod fixing tool 12 having a groove 12a formed on the right end surface and a screw formed on the left end is loosely inserted from the right end, and the male screw portion on the left end is the right end of the disconnecting rod 11. It is screwed into the female screw 11a. At the right end of the disconnecting rod fixing tool 12, a holding plug 13 having a groove 13a and a female screw (not shown) formed on the right side is screwed into the center conductor 2 from the right side, and further to the right side of the holding plug 13, as shown in FIG. Similarly, a spacing cylinder 45 having a U-shaped cross section, a stress cone 46 having a padding 46a for relaxing an electric field, a lid 47, a pressing member 48, and the like are attached.

On the other hand, at the left end of the insulating layer 1, a copper seat 15 having a U-shaped vertical cross section and having an annular shape in the right side view, which is not shown, is embedded in advance. A multi-contact 16 having the same shape as the multi-contact 17 mounted on the inner periphery is mounted, and the seat 15 is fixed to the rear surface of the conductor 39 vertically arranged in the equipment chamber 32B on the front side of the partition plate 31e with a bolt (not shown). Has been done.

In the T-shaped bushing thus constructed, when conducting a DC withstanding voltage test of the cable 40 connected to the equipment inside the box through the T-shaped bushing, first, the blind plug portion on the right side. The blind lid 47, the pressing member 48, the stress cone 46, the disconnect rod fixing tool 12, and the like that form the 43 are removed. Next, as shown in FIG. 2 and FIG. 4A showing a partial detailed view of FIG. 2, a cable 30 for connecting the same component as the component constituting the cable connecting portion 44 of FIG.
Together with. On the other hand, normally, as shown in FIG. 3 and FIG. 4 (b) showing a partial detailed view of FIG. 3, a stopper 9 having a threaded portion and a stepped portion formed at the left end is inserted from the right side of FIG. By incorporating the blind plug portion 43, the left end of the disconnecting rod 11 is projected from the insulating layer 1 and is fitted inside the seat 15.

Further, if the blind plug portion 43 is connected to the additional gas-insulated switchgear as shown in FIG.
1 is removed, all the components forming the blind plug portion 43 of FIG. 1 are removed, and the same component as the component forming the cable connecting portion 44 shown in FIG. 1 is connected to the fixture 21 shown in FIG. 4C. By incorporating the cable 20 together and constructing it as shown in, for example, FIG. Also, seat 15
Is embedded in the insulating layer 1 at the time of molding and has the same axial center as the disconnecting rod 11, so that a good contact state can be achieved, heat generation at the contact portion can be reduced, and axial alignment is not necessary. Assembling the box becomes easy.

Therefore, in the T-shaped bushing having such a structure, the T-shaped bushing is attached to the T-shaped bushing without disconnecting the cable from the equipment chamber in which the insulating gas is filled. This can be done by inserting and removing the disconnecting rod from the blind side of the bushing, so that the withstand voltage test of the cable can be easily performed.
It becomes a shape bushing.

In the above embodiment, the groove 19 is provided in the large diameter portion of the disconnecting rod 11 at the right end, and the key 20 that fits in the groove 19 is also embedded in the right end of the through hole of the center conductor 2. As described above, the contact pressure of the multi-contact 17 with the disconnecting rod 11 is high, and therefore the disconnecting rod 11 is inserted when the male screw portion of the fixture 12 is inserted.
May be omitted if does not rotate.

[0025]

As described above, according to the present invention, in the T-shaped bushing in which the central conductor is embedded in the T-shaped insulating layer, and the cable connecting portion is provided at one end of the central conductor, other than the central conductor. The side is a hollow shaft, and the disconnection rod is provided inside the hollow shaft so that the outer circumference is in contact with the hollow shaft and can move back and forth in the axial direction. By embedding the fixed side contact part, it is not necessary to align the disconnecting bar with the fixed side contact part, and it is possible to disconnect the disconnecting bar during the withstand voltage test of the cable. Thus, it is possible to obtain a T-shaped bushing capable of performing a cable resistance test.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a T-shaped bushing of the present invention.

FIG. 2 is a partial cutaway cross-sectional view showing a disconnection state of a disconnection rod when a cable is tested, showing a function of a T-shaped bushing of the present invention.

FIG. 3 is a partially cutaway cross-sectional view showing a state in which a cable is connected to a gas-insulated switchgear via a T-shaped bushing in a view showing an operation of the T-shaped bushing of the present invention.

FIG. 4 is a partial detailed view showing the operation of the T-shaped bushing of the present invention.

FIG. 5 is a view showing different actions of the T-shaped bushing of the present invention.

FIG. 6 is a view showing an example of a conventional gas-insulated switchgear to which a conventional T-shaped bushing is attached.

FIG. 7 is a vertical sectional view showing a conventional T-shaped bushing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulating layer, 2 ... Center conductor, 11 ... Disconnector bar, 15 ... Seat as fixed side contact part, 40 ... Cable.

Front page continued (72) Inventor Kazuhito Horikiri 1st Toshiba Town, Fuchu City, Tokyo Inside Toshiba Fuchu Plant (72) Inventor Nobuo Masaki 1st Toshiba Town, Fuchu City, Tokyo Inside Toshiba Fuchu Plant (72) Invention Person Masaki Ikuta 1st Toshiba Town, Fuchu-shi, Tokyo Inside Toshiba Fuchu Factory (72) Inventor Masaru Miyagawa 1st Toshiba Town, Fuchu-shi, Tokyo Inside Toshiba Fuchu Factory

Claims (1)

[Claims] 1. A T-shaped bushing in which a central conductor is embedded in a T-shaped insulating layer and a cable connecting portion is provided at one end of the central conductor, the other side of the central conductor being a hollow shaft, A fixed side contact portion in which a disconnecting rod whose outer circumference is in contact with the hollow shaft and is movable in the axial direction is provided inside the hollow shaft, and the tip of the disconnecting rod comes into contact with and separates from the tip of the insulating layer on the other side of the central conductor. A T-shaped bushing characterized by being embedded.