JP3386282B2 - Bushing unit for power distribution equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch, a circuit breaker and the like.
Bushing unit for power distribution equipmentG
ToIt is about. [0002] 2. Description of the Related Art Generally, power distribution devices such as switches are attached to power distribution devices.
In the case of a bushing that is
The conductive rod is inserted and fixed, and a lead wire is connected to the outer end of the conductive rod.
At the same time, and a fixed
A pole is provided. And the bush having the above configuration
The ring is attached to a switch or the like in the state shown in FIG.
That is, the conventional bushings 51a, 51b, 51c
Is a flange for each phase.
The flange mounting brackets 52a, 52b, 52c are covered, and
Bolts 52a, 52b, and 52c are bolts 5
Secured by being tightened with a tightening member such as 3
It had been. [0003] However, the conventional technique described above
The bushing in the operation had the following problems. (1) Three-phase bushings for power distribution equipment such as switches
Installation man-hours and mounting parts
The number of parts, such as materials, has increased,
Manufacturing costs of power distribution equipment to which the bushing is attached increase
Was. (2) Conventional bushings are used as raw materials.
Porcelain is generally used, but porcelain bushings are
Careful installation work may cause damage such as cracks.
Need to be done. Also, the bushing attached
Similarly, when installing the distributed power distribution equipment outdoors,
Work with due consideration for bushing damage
I had to do it. Therefore, bushing
Efficiency of assembly work and mounting work of power distribution equipment
Was. In addition, the porcelain bushing is heavy,
Inevitably leads to an increase in the weight of distribution equipment,
Making the work even more difficult. [0005] The present invention solves the above-mentioned problems in the prior art.
It was done in order to erase
Rollers can reduce the number of mounting parts,
The efficiency of installation work and pole work of distribution equipment should be improved.
To provide a bushing unit for distribution equipment
And there. [0006] Means for Solving the Problems The invention according to claim 1
, The multi-phase bushing body is integrated with the flange
And the multi-phase bushing
Zero-phase current flow in the flange part outside thevessel
ButBushing unit for distribution equipment buriedSo
The zero-phase current transformer is divided into
And a detection coil housed in the
The coil is housed in the same case with a gap.
And the fact that it was buried in that state
is there. [0007] [0008] [0009] [0010] [0011] [0012] [0013] [0014] [0015] According to the first aspect of the invention, a multi-phase block is provided.
The thing body is formed integrally with the flange. But
When installing the bushing unit for power distribution equipment.
Therefore, it is not necessary to provide a mounting member for each phase. further,
Zero-phase current transformerIs housed in the same case as the splittable case.
And a detection coil.
Housed in a space with a gap in it
soSince it is embedded in the flange, the strength of the flange
The degree increases. In addition, bushing units for power distribution equipment
Is installed in the distribution equipment, the installation of the zero-phase current transformer is the same.
Complete at times. Therefore, the installation process of the zero-phase current transformer is omitted.
Abbreviated.Even if stress occurs in the case,
When a stress is applied to the output coil, its electrical characteristics change and
There is no possibility that the function of the phase current transformer is impaired. [0016] [0017] [0018] [0019] [0020] [0021] [0022] [0023] 【Example】 (First Embodiment) Hereinafter, the present invention will be described with reference to a sealed device as a power distribution device.
For a cased air switch (hereinafter simply referred to as switch).
The first embodiment embodied in the power source side bushing unit to be attached
An embodiment will be described with reference to FIGS. FIG. 1 shows a bushing unit according to this embodiment.
FIG. Bushing unit 1
Is a three-phase bushing body 2a, 2b, 2c, a flange portion
3, and a plurality of insulating folds 4, 5, and 6 are made of silicone rubber.
It is formed integrally by molding. Bush
The main body consists of three phases: U-phase 2a, V-phase 2b, and W-phase 2c.
And the flange portion at substantially the center in the axial direction.
3 are arranged side by side on a straight line in a state where they are inserted. Also before
The flange portion 3 has an elliptical shape and is shown in FIG. 1 or FIG.
As described above, the zero-phase current transformer 7 is embedded therein. still,
The three-phase bushing bodies 2a, 2b, 2c are respectively
The structure is the same, only the position where
It is like. Therefore, the first embodiment and the second
In the description of the second and third embodiments, the U-phase bushing body 2 is used.
a will be described representatively. The bushing body 2a has a circular cross section.
In addition, as shown in FIG.
You. The insulating folds 4 are disk-shaped and are formed on the bushing body 2a.
It is formed in a flange shape on the outer peripheral surface. Also, insulation
4 are provided on the upper and lower sides of the flange portion 3,
Each insulation layer formed on the upper side of the flange portion 3
4 is from the position close to the flange 3
Upper first insulating fold 4a, upper second insulating fold 4b, upper third
An insulating fold 4c and an upper fourth insulating fold 4d are provided. This
On the other hand, the insulation formed on the lower side of the flange 3
Similarly, the edge fold 4 is located at a position close to the flange 3.
Lower first insulation fold 4e, lower second insulation fold
4f, lower third insulation fold 4g and lower fourth insulation fold 4h
Have been. In the bushing unit 1 of this embodiment, the above
By providing a plurality of edge folds 4, the bushing unit
To increase the creepage distance of the
I have. In the present invention, the upper first insulation fold 4a is
Insulation fold closest to the flange fixing member
Is composed. As shown in FIG. 4, the bushing body 2a
Inside, a conductive rod 8 is provided. Outer end of the conductive rod 8
An engagement hole 9 is formed in a portion (upper side of FIG. 4), and an inner end portion (FIG.
4 is formed with a screw portion 10 (shown in FIG. 1).
At the same time, the fixed electrode mounting plate 11
a is screwed. Then, the fixed electrode fixing plate 11a
A fixed electrode 11b is provided at the tip. Outer end side inside bushing body 2a
A lead wire 12 is provided at the position. Exit 1
Reference numeral 2 denotes a core wire portion 12a formed by bundling a plurality of copper core wires.
Material (usually ethylene propylene rubber, butyl rubber,
Made of polyethylene, etc.)
Have been. And the lead wire 12 is interposed through the insulating coating 12b.
And is bonded to the bushing body 2a with an adhesive.
The core 12a is formed at the outer end of the conductive rod 8
It is swaged at the hole 9. Therefore, the lead wire
12 is electrically connected to the conductive rod 8 and
It is integrated with the ring main body 2a. The zero-phase current transformer 7 is located inside the flange 3.
And is buried along the outer shape of the flange portion 3. Ma
In addition, the zero-phase current transformer 7 is mounted around the entire circumference thereof as described later.
Clamped between the bracket 17 and the switch case 16
Is located in the position. Zero-phase current transformer 7 is shown in FIGS.
As shown in the figure,
Cases 13a and 13b which are made of resin and which can be divided up and down
And the iron core portion 14 housed in the cases 13a and 13b.
And a detection coil 15. The cases 13a and 13b can be divided.
Pressure during molding, or
Even if an external force acts on the cases 13a and 13b due to thermal stress,
The mating surfaces of the upper and lower cases 13a and 13b are slightly shifted.
Absorbs most of its external forces
You. Therefore, the cases 13a, 13
b has a reduced residual stress. The iron core 14 of the zero-phase current transformer 7 has a plurality of thin plates.
They are stacked and formed as a whole in an annular shape. In addition,
A cloth tape 14a is wound around the core 14.
On the outer peripheral surface of the cloth tape 14a,
The detection coil 15 is wound around the circumference. Same detection
A cloth tape 15a is also wound around the outer peripheral surface of the file 15.
ing. Further, as shown in FIG.
5 and the cloth tape 15a wound around its outer peripheral surface
13a and 13b, the cases 13a and 13b
Clearance L between inner wall surface₁, L_Two, L_ThreeHoused in a certain state
Have been. That is, the cases 13a and 13b are
Even if it is further deformed, the external force acts on the detection coil 15.
Never do. Therefore, the pressure during molding,
Residual stress occurs in the cases 13a and 13b due to thermal stress
Or if the flange 3 is attached to the switch
When the stress is generated in the cases 13a and 13b due to
Also, a stress acts on the detection coil 15 and its electrical characteristics
And the function of the zero-phase current transformer 7 is impaired.
There is no fear. As shown in FIGS. 4 and 6, switch case 1
6 is provided with three mounting holes 16a, 16b, 16c.
And the three-phase bushing bodies 2a, 2b, 2c
Inserted into the mounting holes 16a, 16b, 16c respectively.
Have been. The lower surface of the flange portion 3 is in the switch case 16.
It is arranged so that it contacts, and the upper surface
17. Mounting bracket 17 is a low cylinder with a lid
And is provided above the flange portion 3.
The insulating fold 4 has a through hole 18 through which it can be inserted. Ma
In addition, as shown in FIG.
A plurality of insertion holes 19 are provided at equal intervals in the circumferential direction.
Have been. The switch case 16 corresponds to the insertion hole 19
Mounting bolts 20 are stud welded
It has been planted. The mounting bolt 20 is inserted into the insertion hole 19.
It is inserted, and a washer 21 is
The tightening nut 22 is screwed. And the
The flange 3 is tightened by the tightening nut 22.
By the above, the upper cover 17a of the mounting bracket 17 and the switch case
16 is clamped. The mounting bracket
17, mounting bolt 20, washer 21, and tightening nut
22 constitute the flange fixing member of the present invention.
I have. On the lower surface of the flange portion 3, the same flange portion
An annular sealing ridge 23 is provided along the outer shape of 3.
ing. The seal ridge 23 has a semicircular cross section and
It is formed integrally with the flange portion 3. Also, hula
The surface of the switch case 16 in contact with the flange 3 is for sealing
An annular groove 2 having a concave cross section at a position facing the ridge 23
4 are formed. Flange 3 is switch case 16
When it is attached to the sealing ridge 23,
It is inserted. Then, the flange 3 is attached to the mounting bracket 17.
When tightened by the tightening nut 22 through the
The ridge 23 for the tool closely contacts the inner wall surface of the annular groove 24.
Deform to do. Therefore, the flange 3 and
A seal is provided between the switch case 16 and the air inside the switch.
Denseness is maintained. Also, the sealing ridges 23 are arranged all around.
Of the mounting bracket 17 and the switch case 1
Because it is arranged at the position where it is tightened and clamped by 6,
Its sealing properties are improved. The bush in the present embodiment having the above configuration
The operation and effect of the switching unit 1 will be described. Real truth
The bushing unit 1 of the embodiment is a three-phase bushing body 2
a, 2b, 2c, a flange portion 3, and insulating folds 4, 5,
6 are formed integrally and on the lower surface of the flange 3
The sealing ridge 23 is also integrally formed.
Therefore, a bushing should be provided for each phase for the switch.
In comparison with the prior art, the present embodiment has a bushing.
The overall size of the operating unit 1 is reduced, and
Space for mounting the bushing unit 1 in the vessel
It is possible to reduce the size of the switch.
You. Also, the mounting member of the bushing unit 1 or O
Since the number of parts such as rings decreases, the bushing unit
1 and the opening to which the bushing unit 1 is attached.
The production cost of the closure is reduced. In addition, a zero-phase current transformer 7 is provided on the flange 3.
Bushing unit 1 is attached because it is buried
That the zero-phase current transformer 7 is assembled at the same time
become. Therefore, in this embodiment, the zero-phase current transformer 7 is assembled.
The process can be omitted, and the switch assembly process is shortened.
Have been. Further, the bushing unit 1 of this embodiment
Uses silicone rubber as the molding material,
Weather resistance and cracking, etc.
No. Therefore, compared to porcelain bushings,
Easy handling, assembly process of bushing unit 1
Is shortened. More specifically, conventional porcelain
Excessive tightening of the bushing when fastening it to a switch
Force, or when tightening
The shing may be damaged if dropped accidentally.
Was. Therefore, be careful when assembling the bushing.
It is required to handle this heavy and the work efficiency is low.
I was down. However, the bushing unit of this embodiment
In the case of unit 1, even if the above tightening force is slightly
Cracks occur only when the amount of elastic deformation in the part 3 increases.
Never. Similarly, even when dropped during work,
The washing unit 1 is not damaged. Therefore,
Singing unit 1 is easy to handle and can be used during assembly
Work efficiency will be greatly improved. In addition,
Mounting the switch with the mounting unit 1 attached outdoors
In the same way, in consideration of breakage of the bushing unit 1,
Since there is no need to do so, work efficiency is improved. In addition to the functions and effects described above, the block of this embodiment
In the flushing unit 1, the flange 3
The installed zero-phase current transformer 7 serves as a strength member for the flange portion 3.
Working. That is, the zero-phase current transformer 7 is shown in FIG.
So that the upper cover 17a of the mounting bracket 17 and the switch case
16 and the same position
The cases 13a and 13b of the phase transformer 7 are made of the material of the flange portion 3.
Quality, that is, Epoxy with greater elastic strength than silicone rubber
It is made of resin. Therefore, the flange
3. Strength of the part tightened by the mounting bracket 17 in
And the switch case 16 is more firmly
The mounting part can be attached. Further, silicone rubber as a molding material is
Since the flange portion 3 has elasticity, the flange 3
Elastic deformation between switch 7 and switch case 16
And is pinched by both. Therefore, said mouth
Vibration caused by the swing of the wire 12 is transmitted to the tightening nut 22.
Has been reached and the tightening nut 22 has loosened slightly.
However, the tightening force is rarely greatly reduced.
In addition to this, the flange portion 3 is elastically deformed,
The surface pressure on the mounting surface is made uniform, and the flange
The fitting 17 and the switch case 16 are in more close contact
Becomes As a result, the airtightness of the switch is improved. Further, silicon rubber has water repellency.
Even if moisture such as rain adheres to the bushing unit 1,
The entire surface of the
Not much. Therefore, the bushing unit of this embodiment is
In Example 1, the stain resistance is improved. Next, an embodiment other than the first embodiment will be described.
Will be explained. In the following description, it is the same as in the first embodiment.
Alternatively, the corresponding components are the same as in the first embodiment.
The same reference numerals are given and the description is omitted. (Second Embodiment) The present invention is different from the first embodiment in that
Power supply side bushing unit also attached to the switch
A second embodiment of the present invention will be described with reference to FIGS.
explain. FIG. 5 shows the bushing unit 1 of this embodiment.
The state attached to the switch case 16 is shown.
The switch of the present embodiment has a high-pressure arc-extinguishing gas sealed therein.
This is a so-called gas-filled switch. In the bushing unit 1 of this embodiment,
The upper surface of the flange portion 3 is made of a conductive rubber as a conductive material.
25. Also, the upper surface of the flange portion 3
Of the first insulating fold 4a formed at the position closest to
Between the lower surface and the fold 4a and the flange portion 3
Similarly, the peripheral side surface of the bushing body 2a is
It is in a more covered state. In each part
The coating of the conductive rubber 25 is not formed individually,
They are formed integrally and become electrically conductive.
I have. The conductive rubber 25 is covered with a bushing unit.
When molding 1, the molding process is divided into two stages.
It is provided by performing the above. Sand
That is, the portion from which the conductive rubber 25 has been removed in advance is replaced with a normal mode.
Mold with mold material, then apply conductive rubber 25
The conductive rubber 25 is covered with a mold material
Form. Therefore, the conductive rubber 25 in each of the above portions is
The coating is fixedly formed with the bushing body 2a.
Become. In this embodiment, the molding material has insulating properties,
Ethylene propylene rubber (hereinafter referred to as EPR) having excellent weather resistance
And the conductive rubber 25 is the above-described EP.
5 to 25% by weight carbon based on R
You are using Further, in the present embodiment, the conductive
The thickness of the coating formed by the rubber 25 is about 1.5 mm.
is there. If the coating is 1.0mm to 2.0mm thick
In this case, the effect of preventing the corona discharge described later is suitably exhibited.
Can be used, but in the range of 0.3mm to 3.5mm
I just need. FIG. 7 shows that the flange portion 3 is
It shows a state in which it is fastened and fixed. Same flange 3
The conductive rubber is provided between the upper surface of the
25 are interposed. And the flange part 3 is
Between the mounting bracket 17 and the switch case 16 by the socket 22
It is tightened and fixed. Also, on the lower surface of the flange part 3,
Is a sealing ridge 23 provided in the first embodiment.
In addition, another sealing ridge 26 is provided at a predetermined distance from the ridge 23.
It is formed at a distance. Further, the switch case 16
The annular groove is provided at a position corresponding to the another sealing ridge 26.
27 are formed. And each annular groove 2
Sealing ridges 23 and 26 are fitted in
You. Arc-extinguishing gas enclosed inside the switch is high pressure
Therefore, the bushing unit 1 according to the present embodiment
The sealability is improved by using a plurality of projecting ridges. Operation and effect of the second embodiment having the above configuration
The results will be described focusing on the differences from the first embodiment.
You. The dashed line shown in FIG.
Electric field E near bracket 17₁(Distribution of equipotential lines)
are doing. As a comparative example for this, FIG.
The dotted line indicates that the conductive rubber 25 is connected to the bushing unit 1.
Electric field E when not provided_Two(For equipotential lines
Cloth). The electric field E shown as a comparative example from FIG._Two(Two points
(Chain line), the isoelectric near the through hole 18 of the mounting bracket 17
It can be seen that the rank lines are concentrated. In such a state
The electric field E at the inner peripheral edge of the through hole 18_TwoBut very
Between the inner peripheral edge and the upper first insulating fold 4a.
Local insulation breakdown, so-called corona discharge, occurs during
There is a risk. When corona discharge occurs, the
Magnetic waves are generated, causing noise on radios, televisions, and other communication equipment.
Influence (radio disturbance). In addition, corona release
If electricity is repeatedly generated, the bushing unit 1
Problem, which hasten the life of the product and significantly shorten its life.
Becomes To prevent such corona discharge,
The outer shape of the flange portion 3 is increased and provided on the mounting bracket 17.
The distance between the inner peripheral edge of the through hole 18 and the upper first insulating fold 4a
What is necessary is just to increase. However, with such a configuration
The bushing unit 1 will become larger
Is not preferred. On the other hand, the bushing in the present embodiment
Enlarge the external shape of the flange 3 in the unit 1
In the vicinity of the through hole 18 provided in the mounting bracket 17.
Electric field E₁The strength has been reduced. That is, the mounting bracket
17 is attached to the flange part 3,
The metal fitting 17 and the conductive rubber 25 are electrically connected.
State. Therefore, it is covered with the conductive rubber 25.
Potential on the lower surface of the upper first insulation fold 4a
It becomes equal to the potential of the bracket 17. As a result, the through holes 18
The equipotential lines in the vicinity are as shown in FIG.
only a potential gradient is generated inside the hole 1a.
8 between the inner peripheral edge of the upper electrode 8 and the upper first insulating fold 4a.
There are no concentrated lines. Therefore, in this embodiment,
In the bushing unit 1, the mounting bracket 17 and the upper first
Corona discharge between the insulating folds 4a is suppressed.
ing. The mounting holes provided in the switch case 16
16a between the inner peripheral edge and the lower first insulating fold 4e
Is also concerned about the occurrence of corona discharge.
Is filled with arc-extinguishing gas inside the switch as described above.
Since the breakdown voltage is increased, the corona discharge
Does not occur. (Third Embodiment) Hereinafter, a third embodiment will be described.
A description will be given with reference to FIG. 8 focusing on differences from the second embodiment.
I do. The bushing unit 1 in this embodiment is open to the air.
It is a power supply side bushing unit attached to the closing device. No.
The bushing unit 1 of the third embodiment is the same as the second embodiment.
A part of the surface is covered with the conductive rubber 25
I have. The coating with the conductive rubber 25 is performed on the flange 3
Upper and lower surfaces and the peripheral side surface, the lower surface of the upper first insulation fold 4a, the lower
(2) The upper surface of the insulating fold 4e, and the two folds 4a, 4e
On the peripheral side of the bushing body 2a between the flanges 3
It is formed. The conductive rubber 25 of each part
The covers are integrally formed and are all electrically conductive.
Then, as shown in FIG.
When attached to the switch case 16 by the
The potential of the coating of the conductive rubber 25 is different from the potential of the mounting bracket 17.
Become equal. In the third embodiment having the above configuration,
World E₁Is indicated by the dashed line in FIG. Conductive
The conductive rubber 25 and the mounting bracket 17 are electrically connected.
Therefore, the inner peripheral edge of the through hole 18 provided in the mounting bracket 17
The upper first insulation fold 4a is at the same potential, and
The inner peripheral edge of the mounting hole 16a provided in the
The edge folds 4e are also at the same potential. Therefore,
Concentration of equipotential lines near the through hole 18 and the mounting hole 16a
Not seen. Therefore, in the present embodiment, the second embodiment
The corona discharge as described in
It does not occur from the inner peripheral edge of the perforated hole 16a, and can be opened and closed in the air.
It is possible to improve the corona performance of the vessel. The embodiments of the present invention have been described above.
As described above, the above-described embodiment is described as follows.
The configuration can be changed and implemented. (1) In the above embodiment, the three-phase bushing body 2
Although a, 2b, and 2c are arranged in a straight line, for example, 3
Phase bushing bodies 2a, 2b, 2c have a triangular shape
May be arranged as follows. In addition, the bushing bodies 2a, 2
The shape of the flange part 3 depends on the state where b and 2c are arranged.
May be changed from an elliptical shape to, for example, a circular shape. (2) Formed on the lower surface of the flange 3
The sealing ridge 23 is most suitable when the cross section is semicircular.
Good sealing, but not necessarily semicircular
No, for example, even if it is carried out so as to have a convex cross section
Good. That is, the cross section of the sealing ridge 23 is a switch case.
When it is fitted into the annular groove 24 formed in the base 16.
Any shape may be used as long as a certain sealing property is ensured. (3) In the above embodiment, the flange 3
The zero-phase current transformer 7 is mounted through the flange 3
It is buried in a position where it can be pressed all around by 17
However, only a part of the zero-phase current transformer 7 is
The structure may be such that it is pressed by (4) Module for forming the bushing unit 1
In the above embodiment, silicon rubber and E
Although PR is used, it has high dielectric breakdown strength
Good insulation properties, such as butyl rubber or copper
Can be replaced with loloprene rubber. (5) In the second embodiment and the third embodiment
The conductive rubber 25 contains a predetermined amount of carbon in the EPR.
However, instead of EPR, silicone rubber or
Butyl rubber may be used. Further improve conductivity
Metal powder such as gold, silver, copper, and aluminum
May be mixed together with the mixture. (6) For the bushing bodies 2a, 2b, 2c
The formed insulating folds 4, 5, and 6 are bushing units 1
May vary in number or shape depending on the situation in which
You may let it. For example, in a low-fouling area, beneath the flange 3
Omission of insulation folds formed on the side
Increase the shape of insulation folds 4, 5, and 6 in heavily polluted areas
At the same time, the number of insulating folds 4, 5, 6 may be increased.
No. (7) Each of the above embodiments has a switch.
Embodiment of the present invention as a bushing unit 1 to be attached
However, it has been applied to distribution equipment such as circuit breakers and transformers.
Embody as a bushing unit to be attached
Can also. (8) In the above embodiment, the disconnection of the lead wire 12
The edge coating is made of silicone rubber of the same material as the bushing body 2a.
By doing so, the adhesion between the two is further improved. (9) Upper and lower case 1 of zero-phase current transformer 7 in the above embodiment
3a and 13b are made of epoxy resin.
Even if it is Tylene, phenolic resin or other synthetic resin
Good. What is not described in the claims below
And other technologies grasped by the above embodiment.
Ideology and its effects are described. (A) Multi-phase bushing body is integrated by flange
And the multi-phase bushing
Zero-phase current transformer
Is embedded in the lower surface of the flange portion.
Bushing for distribution equipment with a ridge for sealing
Take the knit to the distribution equipment with the flange fixing bracket.
Mounting structure, wherein the sealing ridge is a franc
Formed at the position where it is sandwiched between the power fixing device and the power distribution device
Bushing unit for power distribution equipment
Mounting structure According to the above construction, the flange fixing member is
Tightening force increases sealing pressure at sealing ridge
Therefore, the sealing effect is improved and the bushing unit
The airtightness of the distribution equipment to be attached is improved. Incidentally, the “polymer material” in this specification is referred to as “polymer material”.
Is a polyester resin, polyolefin resin,
Or synthetic resin such as polystyrene resin,
Chloroprene rubber, butyl rubber, silicone rubber, ethylene
And synthetic rubber such as propylene rubber. [0062] According to the first aspect of the present invention, a plurality of phases are provided.
Since the bushing body is formed integrally,
The number of parts can be reduced. As a result, distribution equipment
Bushing unit and bushing unit
Production costs of distribution equipment
You. In addition, the zero-phase current transformer embedded in the flange
The strength of the flange can be increased. further,
The assembly process of the zero-phase current transformer can be omitted., Zero-phase current change
It is possible to prevent the characteristics of the vessel from changing. [0063] [0064] [0065] [0066] [0067]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a bushing unit according to a first embodiment. FIG. 2 is a perspective view showing a state in which an iron core for a zero-phase current transformer is accommodated in a cover. FIG. 3 is an enlarged sectional view of the zero-phase current transformer. FIG. 4 is a partial sectional view showing a state in which the bushing unit is attached to the switch case. FIG. 5 is a partial sectional view showing a state in which a bushing unit according to a second embodiment is attached to a switch case. FIG. 6 is a partial cross-sectional view showing a mounting state of the bushing unit in the first embodiment. FIG. 7 is a partial cross-sectional view showing a mounting state of a bushing unit and an electric field near a mounting bracket in a second embodiment. FIG. 8 is a partial cross-sectional view showing a mounting state of a bushing unit and an electric field near a mounting bracket in a third embodiment. FIG. 9 is a perspective view illustrating a state in which a conventional bushing is attached to a power distribution device such as a switch. [Description of Signs] 1 ... bushing unit, 2a, 2b, 2c ... bushing body, 3 ... flange portion, 4, 5, 6 ... insulating fold, 7 ...
Zero-phase current transformer, 13a, 13b ... case, 14 ... iron core,
16 switchgear case (power distribution equipment), 17 mounting bracket (flange fixing member), 20 mounting bolt (flange fixing member), 21 washer (flange fixing member), 2
2 ... tightening nut (flange fixing member), 25 ... conductive rubber (conductive material), 23, 26 ... sealing ridges.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kozo Kishimoto 1st character small needle in Inuyama City, Aichi Energy Support Co., Ltd. (72) Inventor Katsunori Aoki 1st character small needle in Inuyama City, Aichi Energy Support Co. (72) Inventor Tatsuya Kato No. 1, Kami-Kobari, Inuyama-shi, Aichi Energy Support Co., Ltd. Hei 6-13016 (JP, U) Japanese Utility Model 63-111736 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 17/26 H02B 13/02

Claims (1)

(57) Claims 1. A multi-phase bushing body is integrally molded with a flange portion, and a zero-phase change is provided in the flange portion outside the multi-phase bushing body. A bushing unit for distribution equipment in which a current transformer is buried , wherein the zero-phase current transformer is splittable,
It has a core and a detection coil housed in the case.
The detection coil has a gap in the case.
Distribution that is housed and buried in that condition
Bushing unit for equipment.