JPH0729437A - T-shaped bushing - Google Patents

Abstract

PURPOSE:To provide a T-shaped bushing capable of easily connecting boxes arranged in a line to each other, and easily performing the withstand voltage test of each box. CONSTITUTION:Gutter grooves for inserting the top ends of cables 8 are formed on both ends of the upper part of the insulating layer 4A of a lower bushing 2A having a central conductor 3 buried in the axial center. The upper part of the central conductor 3 has a boss part 3b formed in the center part, and electrodes 3a formed on both the ends. A presser electrode 5 is provided above each electrode 3s, and the core wire 8a of the cable 8 is nipped by the presser electrode 5 and the inner circumference of the electrode 3a. On the upper part of the lower bushing 2A, an upper bushing 2B is arranged opposite thereto, and a silicon gel sheet 10 is inserted into the opposed part of the upper bushing 2B and the lower bushing 2A, excluding the gutter groove parts. The upper bushing 2B and the lower bushing 2A are fastened to the ceiling board 1e of a box body 1 by a pressing metal fitting 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a T-type bushing for connecting a box of metal closed switch gears filled with an insulating gas with a cable.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional T-shaped bushing 21 which constitutes a power receiving facility 1 of each box 1A, 1B, 1C, 1D, 1
It is a perspective view which shows the state penetrated by the ceiling board of E, 1F, 1G, 1H, and 1J, and was connected by the cable 2. FIG. 7 is an enlarged vertical cross-sectional view showing the connecting process of the T-shaped bushing at the rear portion of the ceiling of the boxes 1B, 1D, 1E, and FIG.
FIG. 8 is a partially enlarged detailed view of FIG. 7.

In FIGS. 6, 7 and 8, the box 1B,
As shown in detail in FIG. 7, the ceiling portions of 1D and 1E are T-shaped bushings 23A, which are disclosed in Japanese Patent Publication No. 60-160309.
23B and 23C are respectively provided so as to penetrate, and are airtightly fixed via O-rings (not shown) inserted into the ceiling plate. T-type bushings, which are the same as the T-type bushings 23A, 23B, and 23C, are vertically provided on the ceilings of the other boxes 1A, 1C, 1F, 1G, 1H, and 1J.

These T-shaped bushings 23A, 23B, 23C
In the outer periphery of the substantially T-shaped center conductor 25, an insulating layer 24 cast by epoxy resin is formed into a substantially T-shape, and the box body 1B,
A through hole 23b penetrating left and right in FIG. 7 is formed in a portion (hereinafter, referred to as a head) 23a protruding upward from the ceiling surface of 1D and 1E. A ground layer 23c shown by a broken line is formed on the outer circumference of the head 23a.

In FIGS. 7 and 8, a cylindrical contact 28 is inserted into an end portion of the core wire 2a of the cable 2, and the core wire 2
It is fixed by a wedge 28b inserted from the end face of a. A groove having a concave cross section is formed on the outer periphery of the contactor 28, and an annular contact plate 28a made of a strip-shaped conductive spring material is mounted in the groove.

At both ends of the cable 2, a substantially cylindrical stress cone 26 is inserted into an inner jacket 2b from which the outer jacket 2c has been removed. In the boxes 1D and 1E shown in FIG. It is inserted into 23b and is pressed inward by a pressing tool (not shown).

In the T-shaped bushing thus constructed, for example, the cable 2 is provided between the T-shaped bushings 23B and 23C penetrating the ceiling plates of the boxes 1D and 1E shown in FIG.
When connecting with, first contact 28 and stress cone
The cable 2 in which 26 is not attached is inserted from the left side of the T-shaped bushing 23A, moved to the right as shown by the arrow A, and the tip is projected to the right side of the T-shaped bushing 23B.

A stress cone 26 is inserted into the inner cover 2b at the right end of the projected cable 2 as shown in FIG. 8, a contact 28 is inserted into the tip of the core wire 2a, and a wedge 28b is struck. Similarly, the stress cone 26 is attached to the left inner end 2b of the cable 2 on the left side of the T-shaped bushing 23B as shown in FIG.
And symmetrically insert the contactor 28 and wedge 28
Knock b.

Next, move the cable 2 further to the right,
The contact 28 inserted in the right end of the cable 2 is a T-shaped bushing.
Insert into the head 25a of the center conductor 25 of 23C, and stress cone
26 is a through hole formed in the head 23a of the T-shaped bushing 23C
Insert it into 23b and tighten it with a fastener not shown. Similarly, the stress cone 26 inserted on the left side of this cable 2
Is inserted into the through hole 26 of the head 23a of the T-shaped bushing 23B, and is tightened with a tightening tool (not shown).

Similarly, when connecting the cable 2 between the boxes 1B and 1D, the cable 2 is penetrated from the left side of the box 1B into the T-shaped bushing 23A, and a pair of stress cones 26 are symmetrically inserted and attached. After inserting the contact 28 into both ends, hitting the wedge 28b and inserting the contact plate 28a, the right end contact 28 is inserted into the T-shaped bushing 23B, and the left end contact 28 is inserted into the T-shaped bushing 23A. insert. Similarly, the stress cone 26 is inserted into the left and right T-shaped bushings 23A and 23B and tightened.

When the stress cone 26 is inserted into the through hole 23b of the head portion 23a, the outer circumference of the stress cone 26 and the inner circumference of the through hole 23b are cleaned with alcohol in advance and silicone grease is applied. T-shaped bushing 23C
A blind plug (not shown) is inserted into the right end of the T-shaped bushing 23A and the left end of the T-shaped bushing 23A.

By the way, the gas-insulated switchgear configured as described above is subjected to a withstand voltage test in accordance with the Japan Electrical Manufacturers' Association standard (JEM1425) when shipped from a manufacturing factory, and after the installation is completed at the site, it is operated. Before starting, a predetermined withstand voltage test is conducted according to the electrical equipment technical standard.

When performing a withstand voltage test of the electric equipment in the box 1B shown in FIG. 6, the T-shaped bushing 23 shown in FIG.
Remove the cable 2 inserted in the opening 23b formed on the left side of A, disconnect the electrical equipment housed in the adjacent box, and connect the cable connected to the withstand voltage tester to the axis of the T-shaped bushing 23A. Insert, tighten and connect. When all the withstand voltage tests of the adjacent board are completed, the T of the adjacent board and box B1
Reassemble the cable connecting the shaped bushing.

On the other hand, in the power receiving equipment constituted by the box bodies arranged in this way, when shipped after the combination test in the manufacturing factory, the power receiving equipment is divided into three or four parts and packed by a large truck or the like. It will be transported to the site where the power receiving equipment will be installed.

[0015]

However, in the T-shaped bushing thus configured, the T-shaped bushing 1E is provided on the right side of the right-most box 1E shown in FIG. 7 in the same manner as the boxes 1B and 1C. In the power receiving equipment in which the boxes connected to the shape bushing 23C are adjacent to each other in several planes, and the box at the right end is adjacent to the wall of the building, all the T-shaped bushings of those boxes are connected. The cable 2 is the box body 1 at the left end shown in FIG.
The head 24 of the T-shaped bushing 23A, which is provided on the ceiling of B, must be penetrated and moved rightward in order.

Further, the stress cone 26 and the contact 28 are attached to the cable 2 and the wedge 28b,
Inserting the contact plate 28a and cleaning the inner circumference of the through hole 24a
It must be done on the upper surface of each box that is more than 2 meters from the installation surface of the metal closed switchgear.

Moreover, these operations are performed twice during the test at the manufacturing factory and at the installation site. At the manufacturing factory, the connection part with the connected cable is disassembled for transportation to the installation location of the power receiving equipment, The stress cone 26 and the inner periphery of the through hole 23b of the T-shaped bushing into which the stress cone 26 is inserted must be packed in order to avoid adhesion of dust.

Therefore, an object of the present invention is to obtain a T-shaped bushing in which boxes can be easily connected and a withstand voltage test can be easily performed.

[0019]

According to a first aspect of the present invention, a gutter-shaped groove is formed in a head portion of a T-shaped insulating layer in which a central conductor is embedded in an axial center, in a direction orthogonal to the central conductor. The lower bushing is provided so as to face the head of the central conductor, and the pressing electrode in which the end of the connecting conductor is inserted between the head of the central conductor and the head of the central conductor is provided so as to face the head of the lower bushing. , A T-shaped bushing made of a silicone gel, which is attached to the upper bushing having a groove facing the groove of the lower bushing formed on the surface facing the head of the lower bushing and the facing surface excluding the grooves of the lower bushing and the upper bushing. Is.

The invention according to claim 2 is a lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor in the head of a T-shaped insulating layer in which the central conductor is embedded in the shaft center. , A pressing electrode which is provided so as to face the head of the central conductor and into which the end of the connecting conductor is inserted between the head of the central conductor and the head of the lower bushing. The upper bushing has a groove facing the groove of the lower bushing formed on the surface facing the head, and the rubber sheet having silicone gel applied to the facing surface excluding the grooves of the lower bushing and the upper bushing. It is a shape bushing.

Further, the invention according to claim 3 is a lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor at the head of a T-shaped insulating layer in which the central conductor is embedded in the shaft center. , A pressing electrode which is provided so as to face the head of the central conductor and into which the end of the connecting conductor is inserted between the head of the central conductor and the head of the lower bushing. A T-shaped bushing including an upper bushing in which a groove facing the groove of the lower bushing is formed on a surface facing the head, and a silicone gel inserted in the grooves of the lower bushing and the upper bushing.

Further, the invention according to claim 4 is a lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor at the head of a T-shaped insulating layer in which the central conductor is embedded in the shaft center. ,
The pressing electrode, which is provided so as to face the head of the central conductor, and into which the end of the connecting conductor is inserted between the head of the central conductor, and the head of the lower bushing, are provided so as to face the head of the lower bushing. The upper bushing has a groove facing the groove of the lower bushing formed on the surface facing the lower bushing and the silicone gel inserted in the groove of the lower bushing and the upper bushing. A T-shaped bushing made of epoxy resin or silicone rubber.

[0023]

According to the invention described in claims 1, 3 and 4, the end portion of the connecting conductor is connected to the central conductor by the pressing electrode pressed through the upper bushing, and the upper bushing and the lower bushing face each other. The surface is insulated from the inside by the silicone gel.

Further, in the invention described in claim 2,
The ends of the connection conductors are connected to the center conductor by a pressing electrode pressed through the upper bushing, and the opposing surfaces of the upper bushing and the lower bushing are insulated from each other by a rubber sheet coated with silicone gel.

[0025]

1 is a partial vertical cross-sectional view showing an embodiment of the T-shaped bushing of the invention described in claim 1, when it is attached to a box body 1 of a switchgear.

In FIG. 1, the outer periphery of a substantially T-shaped central conductor 3 which will be described in detail later is insulation-coated with an insulating layer 4A of epoxy resin to form a substantially T-shaped lower bushing 2A. Among these, as shown in FIG. 1, a boss portion 3b is formed on the upper end of the center conductor 3, and a gutter-shaped electrode 3a whose end portion is chamfered in a semicircular shape is formed on both sides of the boss portion 3b. It is formed symmetrically on the left and right.

The upper end surface of the insulating layer 4A is A- in FIG.
In FIG. 2 showing the A cross section, the insulating layer 4 has a half-moon shape.
The upper bushing 2B, which will be described in detail above A, is combined with an insulating layer 4B of an upper bushing 2B, which will be described later, with a slight gap so as to form a perfect circle, that is, it has the same shape as the T-shaped bushing disclosed in JP-A-60-160309. Is formed. Boss 3
A female screw hole 3c is vertically formed at the center of b. The insulating layer 4B placed on the upper surface of the insulating layer 4A is
And a ground layer (not shown) are formed on the outer periphery of the insulating layer 4B so as to be symmetrical with the upper part of the upper bushing 2B. A silicone gel sheet 10 to be described later is inserted between the upper end surface of the insulating layer 4A and the lower end surface of the insulating layer 4B as shown in FIG.

The silicone gel used in this silicone gel sheet is obtained by curing a liquid silicone polymer by an addition reaction and has a crosslink density of 1/5 to 1/10 of that of a general silicone elastomer. Present. Further, in the production of the silicone gel sheet, uncured silicone gel TSE-3063 (trade name, manufactured by Toshiba Silicone Co., Ltd.) is poured into a container having a shallow U-shaped groove made of Teflon under a reduced pressure of 10 mmHg. Room temperature
It was left to stand at 25 ° C for one day and hardened into a gel with a thickness of 1.5 mm.

On the left and right of the upper end of the insulating layer 4A, the ends of a pair of high-voltage crosslinked polyethylene cables (hereinafter referred to as cables) 8 from which the outer cover is peeled off are placed. An annular semiconductive rubber 11 is previously attached to the outer periphery of the base end of the inner jacket 8b of the cable 8. A substantially annular contact ring 6 is previously attached to the core wire 8a exposed at the tip of the cable 8, and a wedge is driven into the end surface of the core wire 8a. On the outer circumference of the contact ring 6, a contact plate 7 made of a conductive spring material is provided.
Is inserted in a ring. On the upper surface of the contact plate 7, a pressing electrode 5 having a recess 5b formed in the center of the upper portion is placed symmetrically with the upper end of the center conductor 3. The lower end of the pressing electrode 5 is opposed to the upper end of the center conductor 3 with a slight gap.

The holding electrode 5 includes gutter-shaped electrodes 5 on the left and right.
a is formed symmetrically with the electrode 3a. In the central portion of the pressing electrode 5, a boss portion projecting downward is provided with a downward boss portion 3b.
The boss portion 5b is formed symmetrically with a concave portion 5c formed on the upper surface thereof, and a through hole that vertically penetrates is formed at the center of the concave portion 5c.

A bolt 12C is inserted into the through hole from above, and the screw portion of the bolt 12C is screwed into the screw hole 3d because it is provided at the upper end of the center conductor 3 and the pressing electrode 5 is
It is fastened to the central conductor 3 by bolts 12C.
As a result, the core wire 8a, together with the contact ring 6 and the contact plate 7,
It is clamped by the upper holding electrode 5 and the lower electrode 3a.

As shown by the alternate long and short dash line on the insulating layer 4B,
In a side view (not shown), a substantially Ω-shaped holding metal fitting 13 is mounted from above, and the lower end of the holding metal fitting 13 is fixed to the ceiling plate 1a of the box body 1 with a bolt 12B. An O-ring 1c is attached to the ceiling plate 1a on the outer peripheral upper surface of the through hole 1b,
The lower part of the insulating layer 4A is provided through the through hole 1b.

A tubular fixing metal member 9 is loosely fitted to the cable 8 in advance, and the fixing metal member 9 is fixed to the side surfaces of the upper and lower insulating layers 4A and 4B by a bolt 12A via a metal 5d. A seal 14 is provided on the outer surface of the fixing member 9 and the peeling portion of the outer cover of the cable 8. On the outer periphery of the portion of the insulating layer 4A protruding above the ceiling plate 1a, a ground layer (not shown) is provided in advance similarly to the outer periphery of the insulating layer 4B.

In the conductor connecting portion thus constructed, the T-shaped bushing (not shown) is provided by the right and left cables 8 on the ceiling of the box body of the switch gear (not shown) adjacent to the left and right of the box body 1. Connected to. The lower end of the center conductor 3 is also connected to a vacuum circuit breaker or the like inside the box body 1 via a disconnecting switch (not shown) housed inside the box body 1.

Thus, the upper end surface of the insulating layer 4A and the insulating layer 4
The T-shaped bushing in which the silicone gel sheet 10 is inserted on the abutting surface excluding the pressing electrode 5 and the electrode 3a on the lower end surface of B is
Since the silicone gel is flexible, it is possible to prevent the entry of air voids, which is sufficiently absorbed into the fitting portion. for that reason,
Even if a test voltage of 30 kV was applied, it could not be detected by a corona tester having a detection sensitivity of 10 pc. Further, although some of the ten T-shaped bushings used in the test did not show the parallelism of the abutting surfaces with high accuracy, partial discharge could not be detected when the test voltage was applied.

After completion of the corona test, heat cycle test by load current (Note; temperature rise value 90 ° C after 8H, energization stopped 12H
30 times), sprayed the color check solution and then cut it to observe the permeation state, but no permeation of the color check solution was observed. In this test, no significant difference from the conventional T-shaped bushing without division was observed.

When the box body having the T-shaped bushing constructed as described above is divided into 3 to 4 parts for carrying the switch gears arranged in rows as shown in FIG. 6,
With the exception of the seal 14 shown in FIG. 1, the bolts 12A are loosened, the left and right fixing brackets 9 are slid toward the jacket side of the cable 8, the upper bushing 2B is removed, and the presser electrode 5 is removed.
Is removed from the lower bushing 2A.

When carrying out a withstand voltage test for each box, the upper bushing 2B is removed and the holding electrode 5 is removed.
An insulator or the like may be laid between the cable 8 and the lower bushing 2A to block the contact between the cable 8 and the lower bushing 2A.

Further, in the power receiving equipment in which the boxes are arranged in rows as shown in FIG. 6, even when the cables are connected after the divided boxes are installed, the cables are connected to the leftmost box 1A as described above. Since it is not necessary to pass from the attached T-shaped bushing to the T-shaped bushing attached to the right end box 1J in order, the installation period can be shortened, and dust during the installation work can enter the upper and lower bushings. It is possible to eliminate the risk of doing so.

In the above embodiment, instead of the silicone gel sheet 10, a rubber sheet coated with uncured silicone gel and having good insulating properties may be inserted to provide the invention according to claim 2.

Next, FIG. 3 shows the T of the invention described in claim 3.
4 is a front view showing the shape bushing, which corresponds to FIG. 1, and FIG.
FIG. 4 is a side view of FIG. 3 and also corresponds to FIG. 2. The detailed parts are the same as those in FIGS. 1 and 2 and are omitted.

In FIGS. 3 and 4, the upper bushing 2
Between the insulating layer of C and the pressing electrode 5, and the lower bushing 2D
A layer of silicone gel 15 is formed between the insulating layer and the upper outer circumference of the central conductor 3 and in the portions overlapping the inner circumferences of the left and right gutter-shaped portions of the upper bushing 2C and the lower bushing 2D.

Also in this case, similarly to the T-shaped bushing shown in FIGS. 1 and 2, the connection of the cable to the box and the withstand voltage test can be easily performed by removing the upper bushing 2C from above. It can be carried out.

In the T-type bushing described with reference to FIGS. 1, 2, 3 and 4, the upper and lower insulating layers are described as an example of epoxy resin. However, one side of the upper and lower insulating resins is made of silicone rubber, A silicone gel may be interposed between the silicone rubber and the epoxy resin on the other side to face each other. Further, as shown in FIGS. 3 and 4, it may be formed on the outer periphery of the charging portion at the center and the left and right gutter-shaped portions, or may be formed only on the silicone rubber side.

Next, FIG. 5 shows another embodiment of the T-shaped bushing shown in FIGS. 1 to 4, in which the number of head divisions, the division position, and the direction are changed. Of these, (a) shows the side divided into three parts, the lower bushing 2E, the upper one side bushing 2F1 and the upper other side bushing 2F2. Also,
(B) shows an example in which the opposing surfaces of the divided parts of the lower bushing 2G and the upper bushing 2H are corrugated to increase the insulation creepage distance. (C) is an example of increasing the creepage distance by inclining the dividing surface of the lower bushing 2J2 and the upper bushing 2J1, and (d) is a creeping distance in which the dividing surface of the lower bushing 2K and the upper bushing 2L is curved. Increase
(E) is a lower bushing 2M in which (d) is turned upside down.
And the upper bushing 2N, and (f) shows that the insulating layer of the lower bushing 2P is 90 ° and the upper bushing 2Q is
In this example, the insulating layer of 270 ° is used.

[0046]

As described above, according to the invention of claim 1,
A lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor at the head of a T-shaped insulating layer in which the central conductor is embedded in the axis, and a central conductor provided so as to face the head of the central conductor. The pressing electrode into which the end of the connecting conductor is inserted between the head of the lower bushing and the head of the lower bushing are provided so as to face each other, and the surface of the lower bushing facing the head faces the groove of the lower bushing. By forming a T-shaped bushing with the upper bushing in which the groove is formed and the lower bushing and the silicone gel inserted on the opposite surface of the upper bushing excluding the groove, the end portion of the connecting conductor is connected via the upper bushing. It is connected to the center conductor by the pressing electrode that is pressed, and the opposing surfaces of the upper and lower bushings are insulated from the inside and outside by silicone gel, so the boxes can be easily connected and the withstand voltage test is also easy. Line It can be obtained T-shaped bushing that can.

According to the second aspect of the present invention, the lower portion in which a trough-shaped groove is formed in the direction orthogonal to the central conductor in the head of the T-shaped insulating layer in which the central conductor is embedded in the shaft center. The holding electrode, which is provided so as to face the head portion of the central conductor and has the end portion of the connecting conductor inserted between the bushing and the head portion of the central conductor, is provided so as to face the head portion of the lower bushing. The upper bushing has a groove that faces the groove of the lower bushing on the surface that faces the head of the bushing, and the rubber sheet that is attached to the facing surface excluding the grooves of the lower bushing and the upper bushing and is coated with silicone gel. By configuring the T-shaped bushing, the end portion of the connecting conductor is connected to the center conductor by the holding electrode pressed through the upper bushing, and the facing surface of the upper bushing and the lower bushing is a rubber sheet coated with silicone gel. Thus since the internal and external insulated,
It is possible to obtain a T-shaped bushing in which boxes can be easily connected and a withstand voltage test can be easily performed.

According to the third aspect of the present invention, a lower portion in which a trough-shaped groove is formed in the direction orthogonal to the central conductor in the head of the T-shaped insulating layer in which the central conductor is embedded in the shaft center. The holding electrode, which is provided so as to face the head portion of the central conductor and has the end portion of the connecting conductor inserted between the bushing and the head portion of the central conductor, is provided so as to face the head portion of the lower bushing. By forming a T-shaped bushing with an upper bushing in which a groove facing the groove of the lower bushing is formed on the surface facing the head of the bushing, and a silicone gel inserted in the groove of the lower bushing and the upper bushing, The end portion of the connecting conductor is connected to the center conductor by the pressing electrode pressed through the upper bushing, and the opposing surfaces of the upper bushing and the lower bushing are
Since the inside and the outside are insulated by the silicone gel, it is possible to obtain a T-shaped bushing in which the boxes can be easily connected and the withstand voltage test can be easily performed.

Further, according to the invention of claim 4,
A lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor at the head of a T-shaped insulating layer in which the central conductor is embedded in the axis, and a central conductor provided so as to face the head of the central conductor. The pressing electrode into which the end of the connecting conductor is inserted between the head of the lower bushing and the head of the lower bushing are provided so as to face each other, and the surface of the lower bushing facing the head faces the groove of the lower bushing. The upper bushing having the groove and the silicone gel inserted in the grooves of the lower bushing and the upper bushing are
The bushing is formed, and the insulating layer of the upper bushing and / or the lower bushing is made of epoxy resin or silicone rubber, so that the end portion of the connecting conductor is connected to the central conductor by the pressing electrode pressed through the upper bushing. Since the inner surface and the outer surface of the upper bushing and the lower bushing are opposed to each other by using a silicone gel, the boxes can be easily connected to each other and a withstand voltage test can be easily performed. it can.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a T-shaped bushing of the invention described in claims 1 and 2. FIG.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a front view showing an embodiment of the T-shaped bushing of the invention according to claim 3;

FIG. 4 is a right side view of FIG.

FIG. 5 is a right side view showing another embodiment of the T-shaped bushing of the present invention.

FIG. 6 is a perspective view showing a power receiving board in which a conventional T-shaped bushing is incorporated.

FIG. 7 is a vertical cross-sectional view showing a process of assembling a conventional T-shaped bushing to a power receiving board.

FIG. 8 is a partially enlarged view of FIG.

[Explanation of symbols]

1 ... Box, 2A, 2D, 2E, 2G ... Lower bushing,
2B, 2C, 2H ... upper bushing, 3 ... central conductor, 5
... Pressing electrode, 6 ... Contact ring, 7 ... Contact plate, 8 ... High-pressure cross-linked polyethylene cable, 9 ... Fixing metal fitting, 10 ... Silicone gel sheet, 11 ... Semi-conductive rubber, 12A, 12B, 12C ... Bolt, 13 ... Holding metal fitting , 14… Seal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Kase 2-1-1, Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Electric Wire & Cable Co., Ltd. No. 1-1 No. 1 Showa Densen Denki Co., Ltd. (72) Inventor Shin Kinoshita No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Fuchu Plant Co., Ltd. (72) Ken-ichi Sato No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corp. Fuchu Factory (72) Inventor Nobuo Masaki 1st Toshiba Town, Fuchu, Tokyo, Tokyo Fuchu Factory Ltd. (72) Inventor Tetsuo Yoshida 1st Toshiba Town, Fuchu, Tokyo Toshiba Factory (72) Inventor Hiroshi Sonobe 2121 Nawao, Asahi-machi, Mie-gun, Mie Prefecture Toshiba Mie Plant (72) Inventor Masaru Miyagawa No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Fuchu in the factory

Claims (4)

[Claims] 1. A lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor at the head of a T-shaped insulating layer in which a central conductor is embedded in an axial center, and at the head of the central conductor. A pressing electrode in which the end portion of the connecting conductor is inserted between the head portion of the central conductor and the head portion of the central conductor, and a head electrode of the lower bushing which is provided so as to face the head portion of the lower bushing. A T-shaped bushing comprising: an upper bushing having a groove formed on an opposite surface thereof, the groove being opposed to the groove of the lower bushing; and a silicone gel inserted on the opposite surface of the lower bushing and the upper bushing excluding the groove. 2. A lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor in a head of a T-shaped insulating layer in which a central conductor is embedded in an axial center, and in a head of the central conductor. A pressing electrode in which the end portion of the connecting conductor is inserted between the head portion of the central conductor and the head portion of the central conductor, and a head electrode of the lower bushing which is provided so as to face the head portion of the lower bushing. The upper bushing has a groove formed to face the groove of the lower bushing on the opposite surface, and a rubber sheet coated with silicone gel and attached to the opposite surface of the lower bushing and the upper bushing excluding the groove. Shape bushing. 3. A lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor at the head of a T-shaped insulating layer in which the central conductor is embedded in the axial center, and at the head of the central conductor. A pressing electrode in which the end portion of the connecting conductor is inserted between the head portion of the central conductor and the head portion of the central conductor, and a head electrode of the lower bushing which is provided so as to face the head portion of the lower bushing. A T-shaped bushing comprising an upper bushing having a groove formed on the opposite surface and facing the groove of the lower bushing, and a silicone gel inserted in the groove of the lower bushing and the upper bushing. 4. A lower bushing in which a trough-shaped groove is formed in a direction orthogonal to the central conductor in a head of a T-shaped insulating layer in which a central conductor is embedded in an axial center, and in a head of the central conductor. A pressing electrode in which the end portion of the connecting conductor is inserted between the head portion of the central conductor and the head portion of the central conductor, and a head electrode of the lower bushing which is provided so as to face the head portion of the lower bushing. The upper bushing has a groove formed on the opposite surface to face the groove of the lower bushing, and the lower bushing and a silicone gel inserted in the groove of the upper bushing. A T-shaped bushing having an insulating layer made of epoxy resin or silicone rubber.