JPH08273463A - Bushing unit for distribution apparatus and fitting structure for bushing unit - Google Patents

Abstract

PURPOSE: To miniaturize a bushing unit for a distribution apparatus and prevent the bushing unit from being broken, e.g. being cracked. CONSTITUTION: A bushing main body 3, a flange section 4, and insulating ribs 5 are integrally molded with silicone rubber. A zero-phase current transformer 6 is buried in the flange section 4, and a sealing protruded stripe 23 is integrally formed on its lower face. Three-phase insulated electric wires 11a-11c are inserted into the bushing main body 3. Connecting conductor sections 13a-13c are arranged in the middle of the insulated electric wires 11a-11c, and the copper core wires of the insulated electric wires 11a-11c are caulked in the insertion holes 14 formed at both ends of the connecting conductor sections 13a-13c. The insulated electric wires 11a-11c are hooked by interval holding plates 15a-15c to be located at the vertexes of a triangle on the cross section of the bushing main body 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing unit for power distribution equipment used for switches, circuit breakers and the like, and a mounting structure for the bushing unit.

[0002]

2. Description of the Related Art Generally, in a bushing attached to a power distribution device such as a switch or a circuit breaker, a conductive rod is inserted and fixed in an axially extending bore, and the outer end of the conductive rod has a mouth. The outgoing line is connected, and a fixed electrode is provided on the inner end of the outgoing line via a connecting fitting. In the bushing having the above-described structure, the flange portion is provided on the outer periphery of the bushing for each phase, and the flange fitting is tightened with bolts or the like planted in a case such as a switch. It was attached to a switch or the like by being fixed by tightening with an attachment member.

[0003]

However, there are the following problems with the above-mentioned conventional bushing. (1) Since three-phase bushings are attached to each power distribution device such as a switch for each phase, the number of man-hours for mounting the bushing increases and the number of parts such as the mounting member and the sealing member increases. Further, since the three-phase bushings are separate from each other, the overall size of the bushing is increased, and a space for mounting the bushing is required, resulting in an increase in the size of power distribution equipment and the like.

(2) Porcelain is generally used as a raw material for the bushing, but the bushing made of porcelain may be broken or broken. Therefore, it was necessary to carefully install the bushing. In addition, when the power distribution device to which the bushing is attached is installed outdoors, similarly, the work must be performed with due consideration for damage such as cracking. As a result, the work efficiency in the work of installing the bushing or the work of installing the pillar of the power distribution device has been reduced. In addition to this, the weight of the porcelain bushing makes the above-mentioned work even more difficult.

The present invention has been made in view of the above problems, and it is an object of the present invention to reduce the size of the entire bushing unit for power distribution equipment attached to the power distribution equipment. It is an object of the present invention to provide a bushing unit for a power distribution device, which has no fear of damage such as cracking and can improve the efficiency of the assembling work.

[0006]

According to a first aspect of the present invention, there is provided a bushing for a power distribution device in which a single bushing body and a flange portion are integrally molded with an insulating polymer material. A three-phase package type bushing unit for power distribution equipment, characterized in that two insulating coated conductors are respectively arranged at the vertices of a triangle and penetrated through the inside of the bushing body as means for solving the above technical problems. Is.

According to a second aspect of the present invention, in the bushing unit for power distribution equipment according to the first aspect, the three insulated coated conductors are insulated wires, and the insulated wires are provided in the middle of the insulated wires. The gist is that an invasion inhibiting means for restricting the movement of water in is provided.

The invention described in claim 3 is the invention according to claim 1 or 2.
In the bushing unit for a power distribution device described in any one of the above items, a gist is that an iron core portion for a zero-phase current transformer is embedded in the flange portion.

According to a fourth aspect of the present invention, in the bushing unit for power distribution equipment according to the third aspect, the iron core portion is accommodated in the case with a gap, and is embedded in that state. This is the summary.

The invention according to claim 5 is the invention according to claims 1 to 4.
In the bushing unit for a power distribution device described in any one of the above items, the gist is that the insulating polymer material is ethylene propylene rubber or silicon rubber.

The invention according to claim 6 is the same as claims 1 to 5.
In the bushing unit for a power distribution device described in any one of the above, the gist is that a sealing projection is integrally formed on the lower surface of the flange portion.

A seventh aspect of the present invention is based on a gist of the bushing unit for a power distribution device according to the sixth aspect, wherein the sealing ridge has an arcuate cross section.

The invention according to claim 8 is the invention according to claim 6 or 7.
In the bushing unit for a power distribution device described in any one of the above, the gist is that a plurality of the protrusions for sealing are formed.

According to a ninth aspect of the present invention, one bushing body and the flange portion are integrally molded with an insulating polymer material, and three insulating coated conductors are respectively arranged at the vertices of a triangle. And a bushing unit for a three-phase batch type power distribution device in which the interior of the bushing is penetrated and a zero-phase current transformer is embedded in the flange part, and is attached to the power distribution device by a flange fixing member. Then, at least a part of the zero-phase current transformer is sandwiched between the flange part fixing member and the power distribution device via the flange part.

According to a tenth aspect of the present invention, one bushing body and the flange portion are integrally molded with an insulating polymer material, and three insulating coated conductors are respectively arranged at the apexes of a triangle. Then, there is provided a mounting structure for mounting a three-phase batch type bushing unit for power distribution equipment penetrating the inside of the bushing body to the power distribution equipment by a flange fixing member, wherein the flange fixing member has conductivity. , And at least the insulating layer provided at a position closest to the flange fixing member from the upper surface of the flange fixed by the flange fixing member is provided with a coating layer made of a conductive material. To do.

[0016]

In the bushing unit for power distribution equipment according to the first aspect of the present invention, the three-phase insulating coated conductors are collectively provided inside one bushing body, and the insulating coated conductors are located at the apexes of the triangle. Will be placed. Therefore, the entire bushing unit for power distribution equipment is downsized. Further, in the bushing unit for power distribution equipment of the present invention, since the insulating polymer material is used as the molding material, there is no risk of cracking, and the weight is lighter than that of a porcelain bushing.

According to the invention of claim 2, claim 1
In addition to the effect of the invention described in (1), even if the insulated wire is damaged and water such as rainwater enters the inside of the wire, the movement of the water is restricted by the intrusion prevention means, so the inside of the power distribution equipment Never infiltrate.

According to the invention of claim 3, claim 1
In addition to the effect of the invention described in any one of items 1 and 2, the strength of the flange portion is increased by the iron core portion for the zero-phase current transformer embedded in the flange portion. In addition, when the bushing unit for power distribution equipment of the present invention is attached to the power distribution equipment, the installation of the zero-phase current transformer is completed at the same time. Therefore, the step of mounting the zero-phase current transformer is omitted.

According to the invention of claim 4, claim 3
In addition to the effect of the invention described in (1), since the iron core part of the zero-phase current transformer is housed in the case, no external force is applied to the iron core part and the characteristics of the zero-phase current transformer do not change. .

According to the invention of claim 5, claim 1
In addition to the effect of the invention described in any one of 4 to 4, the insulation and weather resistance of the bushing unit for power distribution equipment are improved. In particular, when silicon rubber is used as the insulating polymer material, water repellency is imparted to the bushing unit for power distribution equipment.

According to the invention of claim 6, claim 1
In addition to the action of the invention described in any one of 1 to 5, the airtightness inside the switch etc. to which the bushing unit for power distribution equipment is attached is enhanced by the sealing ridge integrally formed on the lower surface of the flange portion. . Further, according to the invention described in claim 7, in which the sealing member is unnecessary, in addition to the action of the invention described in claim 6, the sealing property of the sealing ridge is improved.

According to the invention described in claim 8, in addition to the action of the invention described in claim 6 or 7, the sealing property of the sealing ridge is improved. According to the invention described in claim 9, when the flange portion is attached to the power distribution device, the external force from the flange portion fixing member acts on the zero-phase current transformer. That is, the zero-phase current transformer acts as a strength member in the flange portion. As a result, the mounting strength at the flange portion of the bushing unit for power distribution equipment increases.

According to the tenth aspect of the invention, when the flange fixing member is attached to the upper surface of the flange on which the coating layer made of a conductive material is formed, the potential of the coating layer is the same. It becomes equal to the potential of the part fixing member. As a result, the electric potential of the insulating fold closest to the flange fixing member becomes equal to that of the flange fixing member.
Therefore, the electric field strength between the flange fixing member and the insulating folds is relaxed, and corona discharge between them is suppressed.

[0024]

【Example】

(First Embodiment) A first embodiment in which the present invention is embodied as a power source side bushing unit of an air switch in a hermetically sealed case will be described with reference to FIGS.

FIG. 1 is a sectional view showing a state in which the bushing unit 1 in this embodiment is attached to the switch case 2. As shown in the figure, the bushing unit 1 in this embodiment includes a bushing body 3, a flange portion 4, and an insulating fold 5, which are integrally formed by using silicone rubber having excellent insulation and weather resistance as a molding material. It is molded. The bushing body 3 has a substantially columnar shape, and a flange portion 4 having a disk-shaped cross section is provided in a protruding manner on an outer peripheral surface at a substantially central portion in the axial direction, and a plurality of insulating folds 5 are provided on the flange portion 4 above. Are formed.

A zero-phase current transformer 6 is provided inside the flange portion 4.
Is buried. The zero-phase current transformer 6 includes upper and lower cases 7a and 7a.
b and the iron core portion 8 housed in the cases 7a and 7b. FIG. 2 shows cases 7a and 7 of the zero-phase current transformer 6.
3B shows a cross section of the iron core portion 8 housed in the cases 7a and 7b. Cases 7a, 7b
Is made of epoxy resin in a ring shape and is vertically separable. With such a configuration, even if an external force acts on the cases 7a and 7b, the mating surfaces of the upper and lower cases 7a and 7b are slightly displaced, so that most of the external force is alleviated.

The iron core portion 8 housed in the cases 7a and 7b includes an iron core 9 and a detection coil 10. Same iron core 9
Is formed by laminating a plurality of thin plate materials and forming an entire ring shape. A cloth tape 9a is wound around the iron core 9, and a detection coil 10 is wound around the entire circumference of the iron tape 9 on the outer peripheral surface of the cloth tape 9a. Further, a cloth tape 10a is wound around the outer peripheral surface of the detection coil 10. In addition, as shown in FIG.
It is accommodated in a state in which gaps L ₁ , L ₂ and L ₃ are provided between the inner wall surface of b and the inner wall surface. That is, even if the cases 7a and 7b are deformed and stress is generated, the stress does not act on the iron core portion 8. Therefore, the pressure during molding,
Even if residual stress is generated in the cases 7a and 7b due to thermal stress, or even if stress is generated in the cases 7a and 7b by attaching the flange portion 4 to a switch as described later, the electric power of the iron core portion 8 is reduced. Characteristics do not change due to the action of the stress, and the function of the zero-phase current transformer 6 is not impaired.

The insulating pleats 5 formed on the upper side of the flange portion 4 are formed in a disk shape having a smaller diameter than the flange portion 4. In the bushing unit 1 of this embodiment, 4
Two insulating folds 5 are formed at predetermined intervals in the axial direction. The insulating folds 5 arranged at the positions closest to the flange 4 are the first insulating folds 5 of the respective insulating folds 5.
a, and a second insulating fold 5b, a third insulating fold 5c, and a fourth insulating fold 5d are arranged in this order from the first insulating fold 5a toward the outer end side (upper side in FIG. 1) of the bushing unit 1. . By providing the plurality of insulating folds 5 in this manner, the creeping distance of the bushing unit 1 of the present embodiment is increased, and the stain resistance is improved.

Three-phase insulated wires 11a, 11b, 11c are embedded in the bushing body 3 so as to penetrate in the axial direction. Connection conductors 13a to 13c (described later) are arranged in the middle of the insulated wires 11a to 11c. The insulated electric wires 11a to 11c have core wire portions 12a to 12c formed by bundling a plurality of copper core wires, which are insulation-coated with a molding material (usually ethylene propylene rubber, butyl rubber, polyethylene or the like). The insulated wires 11a to 11c form the insulation-coated conductor of the present invention.

The above-described connecting conductor portions 13a, 13b, 13c are provided in the insulated electric wires 11a to 11c at positions near the outer ends of the bushing body 3, respectively. Engagement holes 14 are formed on the outer end side and inner end side (upper and lower end sides in FIG. 1) of the connection conductor portions 13a to 13c. Then, the exposed core wires 12a to 12c of the insulated electric wires 11a to 11c are inserted into the engaging hole 14 and are caulked. The connection conductor portions 13a to 13c constitute the invasion inhibiting means of the present invention.

FIG. 4 is a sectional view taken along line AA in FIG.
The three-phase insulated wires 11a to 11c are the bushing body 3
It shows a position arranged inside. As shown in FIG. 4, the space holding plate 1 having an equilateral triangle shape is provided at a position surrounded by the insulated wires 11a to 11c.
5a is provided. The same distance holding plate 15a is made of the same material as the bushing body 3 such as silicone rubber, and has three notches 16 at each corner. Each of the notches 16 is formed in a semicircular shape having a diameter slightly smaller than the diameter of the insulated electric wires 11a to 11c. Then, the insulated wires 11a to 11c are fitted and locked in the notches 16. By being locked by the notch 16, the insulated electric wires 11 a to 11 c are arranged inside the bushing body 3 so as to be positioned at the vertices of an equilateral triangle. As shown in FIG. 1, in the bushing body 3, a spacing plate 15b similar to the spacing plate 15a described above,
15c are provided at the positions where the connection conductors 13a to 13c are provided and at the inner end side of the bushing body 3, respectively. The insulated wires 11a to 11c are adhered to the bushing body 3 via an adhesive, and the connecting conductor portions 13a to
The bushing unit 1 is formed integrally with the bushing body 3 together with 13c and the spacing plates 15a to 15c.

FIG. 5 shows a state in which the bushing unit 1 is attached to the switch case 2 by the flange portion 4. When the bushing unit 1 is attached, the lower portion of the bushing body 3 is inserted into the attachment hole 2a provided in the switch case 2. The flange portion 4 is arranged such that its lower surface is in contact with the switch case 2, and its upper surface is fixed by a mounting member 17 as a flange portion fixing member. The mounting bracket 17 is the bushing body 3
Is formed in a cylindrical shape with a lid having a through hole 18 through which the insulating fold 5 formed can be inserted. A plurality of insertion holes 19 are provided in the upper lid portion 17a of the mounting member 17 at equal intervals in the circumferential direction. A plurality of mounting bolts 20 are planted in the switch case 2. Same mounting bolt 20
Is inserted into the insertion hole 19, and a tightening nut 22 is screwed to the upper end of the insertion hole 19 via a washer 21. Then, the flange portion 4 is tightened by the tightening nut 22, so that the flange portion 4 is clamped and clamped between the upper lid portion 17 a of the mounting bracket 17 and the switch case 2.

An annular sealing projection 23 is provided on the lower surface of the flange portion 4 along the outer shape of the flange portion 4. The sealing ridge 23 has a semicircular cross section and is formed integrally with the flange portion 4. Further, on the upper surface of the switch case 2, an annular groove 24 having a concave cross section is formed at a position facing the sealing projection 23.
When the bushing unit 1 is attached to the switch case 2, the sealing projection 23 is fitted into the annular groove 24. When the flange portion 4 is tightened by the tightening nut 22 via the mounting bracket 17, the sealing projection 23
Deforms so as to come into close contact with the inner wall surface of the annular groove 24, and the gap between the flange portion 4 and the switch case 2 is sealed. Therefore, the airtightness inside the switch is maintained, and the entry of rain or the like into the switch is suppressed.

As shown in FIG. 5, the zero-phase current transformer 6 embedded in the flange portion 4 has an upper lid portion 17 of the mounting bracket 17.
It is arranged at a position where it is sandwiched by a and the switch case 2 over its entire circumference. Case 7 of zero-phase current transformer 6
Reference characters a and 7b are formed of a material of the flange portion 4, that is, an epoxy resin having a higher elastic strength than silicon rubber. Therefore, the strength of the flange portion 4 in the portion tightened by the mounting bracket 17 is increased, and the flange portion 4 is more firmly attached to the switch case 2.

The operation and effect of the bushing unit 1 of the present embodiment having the above structure will be described. In the bushing unit 1 of this embodiment, the bushing body 3, the flange portion 4, and the insulating fold 5 are all integrally molded. Furthermore, three-phase insulated wire 11
The insulated wires 11a to 11c are collectively penetrated into the bushing body 3, and the insulated wires 11a to 11c are arranged by the spacing plates 15a to 15c so as to be located at the vertices of an equilateral triangle. Therefore, the entire bushing unit 1 is downsized. Further, in the switch to which the bushing unit 1 of the present embodiment is attached, the mounting space can be reduced, and the switch can be downsized.

A sealing projection 23 is integrally formed on the lower surface of the flange portion 4. Therefore, a sealing member such as an O-ring is unnecessary, and the number of parts is reduced. In addition, the number of mounting members such as mounting brackets, tightening nuts, and mounting bolts is reduced compared to the case where the bushing is attached to each phase of the switch. The manufacturing cost of the switch to which the unit 1 is attached can be reduced.

A part of the insulated wires 11a to 11c penetrating the inside of the bushing body 3 is extended from the outer end surface of the bushing body 3 and exposed to the atmosphere. Here, the insulated wire 11a exposed to the atmosphere is used. There is a possibility that some of the materials 11 to 11c may be damaged by cracks or the like due to deterioration over time or deterioration due to ultraviolet rays. In such a case, the insulated wires 11a-11
Water such as rain penetrates into the inside of c, and the water is insulated wire 11
There is a concern that it will penetrate into the switch through the insides of a to 11c. However, in the bushing unit 1 according to the present embodiment, the connecting conductors 13a to 13c are arranged in the middle of the insulated wires 11a to 11c, and the water inside the insulated wires 11a to 11c moves by the connecting conductors 13a to 13c. Is regulated. Therefore, the above-mentioned problems do not occur. In addition, since the material of the insulating coating provided on the outer circumference of the insulated wires 11a to 11c is the same silicone rubber as the molding material, the bushing unit 1
Is formed by molding, the insulating coating and the bushing body 3 are in extremely close contact with each other. As a result, it is possible to prevent rain or the like from entering the inside of the bushing body 3 through the gap between the insulated wires 11a to 11c and the bushing body 3.

In addition, since the zero-phase current transformer 6 is embedded in the flange portion 4, the work of mounting the bushing unit 1 and the work of mounting the zero-phase current transformer 6 are completed at the same time. Therefore, the step of mounting the zero-phase current transformer 6 can be omitted.

Furthermore, the bushing unit 1 of this embodiment
Since it is formed using silicone rubber as a molding material, there is almost no risk of damage such as cracking. Therefore, it is much easier to handle than a porcelain bushing. More specifically, the conventional porcelain bushing has the same bushing if it is fastened to a switch or the like by an excessive tightening force or if the bushing is accidentally dropped during fastening work. Could damage the. Therefore, the operator has to handle the bushing carefully, and the work efficiency has deteriorated. However, the bushing unit 1 of the present embodiment
Then, even if the tightening force is excessively large, only the amount of elastic deformation of the flange portion 4 increases, and cracking does not occur. Similarly, the bushing unit 1 will not be damaged even if it is dropped during work. Therefore, the work efficiency at the time of assembling the bushing unit 1 is significantly improved. Also, when the switch to which the bushing unit 1 is attached is mounted outdoors, the work efficiency can be improved because damage to the bushing unit 1 need not be taken into consideration.

In addition to the actions and effects described above, in the bushing unit 1 of this embodiment, the zero-phase current transformer 6 embedded in the flange portion 4 acts as a strength member for the flange portion 4. Therefore, the deformation of the flange portion 4 can be suppressed, and the flange portion 4 of the bushing unit 1 can be more firmly attached to the switch case 2.

Further, since the silicone rubber as the molding material has elasticity, the flan portion 4 is attached to the fitting 17
The upper lid portion 17a and the switch case 2 are sandwiched by the two in an elastically deformed state. Such elastic deformation of the flange portion 4 has the following effects. That is, the surface pressure on the mounting surface between the flange portion 4 and the upper lid portion 17a or between the flange portion 4 and the switch case 2 is equalized, and the flange portion 4 and the mounting bracket 17 and the switch cover are in close contact with each other. Becomes As a result, the airtightness of the switch is improved. In addition to this, insulated wires 11a-1
Even if the vibration due to the swing of 1c is transmitted to the tightening nut 22 and the nut is loosened to some extent, the tightening force is not significantly reduced.

Further, since the silicone rubber has water repellency, even if moisture such as rain adheres to the bushing unit 1, it will not be in a wet state, and therefore, the adhesion of dust will be extremely small. As a result, the bushing unit 1 of this embodiment has improved stain resistance.

Embodiments other than the first embodiment will be described below. The basic configuration, action and effect of the bushing unit 1 in the embodiment described below are the same as those in the first embodiment. Therefore, in the following embodiments, the differences from the first embodiment will be mainly described. Further, in the following description, the same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

(Second Embodiment) Like the first embodiment, the present invention is applied to a power source side bushing unit 1 attached to a switch.
A second embodiment embodied in will be described with reference to FIGS. 6 and 7.

FIG. 6 shows a state in which the bushing unit 1 of this embodiment is attached to the switch case 2. The switch of this embodiment is a so-called gas-filled switch in which arc extinguishing gas is filled.

The upper surface of the flange portion 4 provided on the bushing unit 1 is covered with a conductive rubber 25 as a conductive material. In addition, the first insulation fold 5a
The lower surface and the peripheral side surface of the bushing body 3 between the pleats 5 and the flange portion 4 are also covered with the conductive rubber 25. The conductive rubber 25 does not individually cover the above-mentioned portions, but they are integrally formed and are in an electrically conductive state. The coating layer of the conductive rubber 25 is provided by performing the molding process in two stages when molding the bushing unit 1. That is, the portion from which the conductive rubber 25 has been removed in advance is molded with a normal molding material, and then a layer of the conductive rubber 25 is formed with the molding material composed of the conductive rubber 25. Therefore, the coating layer of the conductive rubber 25 on each of the above parts is integrally fixed to the bushing unit 1. In this embodiment, ethylene propylene rubber (hereinafter referred to as EPR) is used as the molding material, and the conductive rubber 25 contains 5 to 25% by weight of carbon relative to the EPR. are doing. In addition, the thickness of the coating formed of the conductive rubber 25 in this embodiment is about 1.5 mm. When the coating has a thickness of 1.0 mm to 2.0 mm, the effect of preventing corona discharge, which will be described later, can be suitably obtained, but it may be in the range of 0.3 mm to 3.5 mm.

FIG. 7 shows a state in which the flange portion 4 is tightened and fixed to the switch case 2 by the mounting bracket 17. The conductive rubber 25 is interposed between the upper surface of the flange portion 4 and the mounting surface of the mounting bracket 17, and the tightening nut 2
2, the flange portion 4 is attached to the switch case 2.

In addition to the sealing projection 23 provided in the first embodiment, another sealing projection 26 is formed on the lower surface of the flange 4 at a predetermined distance from the projection 23. There is. Further, an annular groove 27 is formed on the cover 16 of the switch at a position corresponding to the other sealing projection 26. Then, the sealing projections 23 and 26 are fitted in the respective annular grooves 24 and 27. Since the arc-extinguishing gas enclosed in the switch has a high pressure, the bushing unit 1 of this embodiment has a plurality of sealing ridges to improve the sealing performance.

The operation and effect of the second embodiment having the above construction will be described focusing on the differences from the first embodiment. The dashed-dotted line shown in FIG. 7 represents the state of the electric field E ₁ (distribution of equipotential lines) in the vicinity of the flange portion 4 and the mounting bracket 17. As a comparative example to this, the two-dot chain line in FIG. 7 shows the state of the electric field E ₂ (distribution of equipotential lines) when the conductive rubber 25 is not provided in the bushing unit 1.

It can be seen from FIG. 7 that in the electric field E ₂ (two-dot chain line) shown as a comparative example, equipotential lines are concentrated near the through hole 18 of the mounting member 17. In such a state, the electric field E ₂ at the inner peripheral edge of the through hole 18 becomes extremely large, and a local dielectric breakdown between the inner peripheral edge and the first insulating fold 5, so-called corona, occurs. Discharge may occur. When a corona discharge occurs, electromagnetic waves are generated along with it, and affect radio, TV, and other communication devices as noise (radio interference). Further, when corona discharge is repeatedly generated, deterioration of the bushing unit 1 is accelerated and its life is significantly shortened, which is a problem. To prevent such corona discharge,
The outer shape of the flange portion 4 may be increased to increase the distance between the inner peripheral edge of the through hole 18 provided in the mounting member 17 and the first insulating fold 5a. However, such a configuration is not preferable because the entire bushing unit 1 becomes large.

On the other hand, in this embodiment, the mounting bracket 17
The concentration of equipotential lines in the vicinity of the through hole 18 is alleviated. That is, when the mounting bracket 17 is mounted on the flange portion 4, the mounting bracket 17 and the conductive rubber 2 are attached.
5 becomes conductive. Therefore, the electric potential on the lower surface of the first insulating fold 5 a covered with the conductive rubber 25 becomes equal to the electric potential of the fitting 17. As a result, the equipotential lines in the vicinity of the through hole 18 only have a potential gradient inside the bushing body 3, as shown in FIG.
Equipotential lines do not concentrate between the inner peripheral edge of the through hole 18 and the first insulating fold 5a. As described above, in this example, the occurrence of corona discharge as described in the comparative example is suppressed.

The mounting hole 2 provided in the switch case 2
Corona discharge is also likely to occur between the inner peripheral edge of a and the peripheral side surface of the bushing body 3, but in the present embodiment, as described above, the arc-extinguishing gas is enclosed in the switch. Since the breakdown voltage is increased, the corona discharge does not occur.

(Third Embodiment) The third embodiment will be described below with reference to FIG. 8 focusing on the differences from the second embodiment. The bushing unit 1 in this embodiment is attached to an air switch in a closed case. A part of the surface of the bushing unit 1 of the third embodiment is covered with the conductive rubber 25 as in the second embodiment. The coating layer of the conductive rubber 25 is formed on the upper and lower surfaces and the peripheral side surfaces of the flange portion 4, the lower surface of the first insulating fold 5a, and the peripheral side surface of the bushing body 3 between the insulating fold 5a and the flange portion 4. ing. A part of the peripheral side surface of the bushing body 3 below the flange portion 4 is also covered with the conductive rubber 25. The coating layer of the conductive rubber 25 in each of the above parts is integrally formed and is in an electrically conductive state. As shown in FIG. 8, when the flange portion 4 is attached to the switch case 2 by the mounting bracket 17, the switch case 2, the mounting bracket 17 and the conductive rubber 25 all have the same potential.

The electric field E ₁ in the third embodiment having the above construction is as shown by the alternate long and short dash line in FIG. Since the coating layer of the conductive rubber 25 is equal to the potential of the mounting member 17, the inner peripheral edge of the through hole 18 of the mounting member 17 and the first insulating fold 5a have the same potential, and the switch case 2 has The inner peripheral edge of the mounting hole 2a provided and the peripheral side surface of the bushing body 3 below the flange portion 4 are also at the same potential. Therefore, the equipotential lines are not concentrated near the through hole 18 and the mounting hole 2a. Therefore, in this embodiment, the corona discharge as described in the second embodiment does not occur from the inner peripheral edge of the through hole 18 and the mounting hole 2a, and the corona performance of the switch can be improved. It will be possible.

Although the respective embodiments embodying the present invention have been described above, the above-mentioned embodiments can be implemented by changing the configuration thereof as described below. (1) In the above embodiment, the three insulated wires are arranged inside the bushing body 3 so as to be positioned at the apexes of the regular triangle. The most stable electrical characteristics can be obtained when the three insulated wires are placed at the vertices of a regular triangle, but this is at the vertices of an isosceles triangle and an isosceles triangle. The arrangement may be such that

(2) Although the upper and lower cases 7a and 7b of the zero-phase current transformer 6 are made of epoxy resin in the above embodiment, they may be made of polyethylene, phenol resin or other synthetic resin.

(3) The sealing ridges 23 and 26 formed on the lower surface of the flange portion 4 have the best sealing performance when the cross section has a semicircular shape, but do not necessarily have to have a semicircular shape. Instead, it may be implemented, for example, so as to have a convex cross section. That is, the sealing ridges 23 and 26 may have a cross-section that has a shape that ensures a certain sealing property when fitted into the annular grooves 24 and 27 formed in the switch case 2.

(4) In the above embodiment, the flange portion 4
The zero-phase current transformer 6 in the inside is buried in a position where it is held by the mounting bracket 17 over the entire circumference thereof via the flange portion 4, but only a part of the zero-phase current transformer 6 is mounted in the mounting bracket 17.
It may be configured to be pressed by.

(5) As the molding material for forming the bushing unit 1, silicone rubber and E are used in the above embodiment.
Although PR is used, it can be replaced with one having a high dielectric breakdown strength and good insulating properties, such as butyl rubber or chloropyrene rubber.

(6) The conductive rubber 25 in the second and third embodiments is EPR containing a predetermined amount of carbon, but silicon rubber or butyl rubber may be used instead of EPR. Further, in order to improve conductivity, metal powder such as gold, silver, copper, aluminum may be mixed with carbon.

(7) The number or shape of the insulating pleats 5 formed on the bushing body 3 may be changed according to the situation in which the bushing unit 1 is used. For example, the number of insulating folds 5 may be reduced in the low-pollution area, and the shape of the insulating folds 5 may be increased and the number of the insulating folds 5 may be increased in the heavy-pollution area such as a salt-damaged area.

(8) In the above embodiment, if the insulating coating of the lead wire 12 is made of the same material as the bushing main body 3 such as silicone rubber, the adhesion between the two is further improved. (9) In all of the above embodiments, the present invention is embodied as the bushing unit 1 attached to the switch, but it should be embodied as a bushing unit attached to a distribution device such as a breaker or a transformer. You can also

Hereinafter, other technical ideas which are not described in the scope of claims and which are grasped by the above-mentioned embodiments will be described together with their effects. (A) One bushing body and a flange part are integrally molded with a polymer material, and three insulating coated conductors are respectively arranged at the apexes of a triangle to penetrate the inside of the bushing body, and A mounting structure for mounting a bushing unit for power distribution equipment integrally formed on a lower surface of a flange portion to a power distribution equipment by a flange fixing member, wherein the sealing projection is fixed to the flange portion. A bushing unit mounting structure for a power distribution device, which is sandwiched between a member and the power distribution device.

According to the above construction, the sealing pressure in the sealing means is increased and the sealing effect is improved. The “insulating polymer material” in the present specification includes synthetic resins such as polyester resins, polyolefin resins, or polystyrene resins, and also includes chloroprene rubber, butyl rubber, silicone rubber, ethylene propylene. Includes synthetic rubber such as rubber.

[0065]

According to the bushing unit for power distribution equipment described in claim 1, the bushing unit can be downsized as a whole. In addition, since the bushing unit for a power distribution device can be made lighter because it is made of an insulating polymer material, it is possible to prevent the bushing unit from cracking. Therefore, the handling is facilitated, and the efficiency of the work for assembling the bushing unit for power distribution equipment can be improved. Further, since the mounting bolt, the fixing member, and the like are common to each phase, the number of mounting parts can be reduced, and the manufacturing cost of the bushing unit for power distribution equipment and the power distribution equipment to which the bushing unit is attached can be reduced.

According to the invention described in claim 2, claim 1
In addition to the effect of the invention described in (1), water can be prevented from entering the distribution equipment through the inside of the insulated wire. Claim 3
According to the invention described in claim 1, in addition to the effect of the invention described in claim 1 or 2, the strength of the flange portion can be increased by the iron core portion of the zero-phase current transformer embedded in the flange portion. it can. In addition, the work of attaching the zero-phase current transformer to the bushing unit for power distribution equipment becomes unnecessary.

According to the invention of claim 4, claim 3
In addition to the effects of the invention described in (1), it is possible to prevent the characteristics of the zero-phase current transformer from changing. According to the invention described in claim 5, in addition to the effect of the invention described in any one of claims 1 to 4, it is possible to improve the insulating property and the weather resistance of the bushing unit for a power distribution device. The life of the can be improved. In particular, in a bushing unit for power distribution equipment using silicon rubber as a polymer material, the water repellency can improve the stain resistance.

According to the invention of claim 6, claim 1
In addition to the effects of the invention described in any one of 5 to 5, since the sealing ridge is integrally formed on the lower surface of the flange portion, a sealing member is not necessary and the number of parts can be reduced.

According to the invention of claim 7, claim 6
In addition to the effect of the invention described in (1), the sealing property of the sealing ridge can be improved. According to the invention described in claim 8, in addition to the effect of the invention described in claim 6 or 7, it is possible to improve the sealing property of the sealing ridge.

According to the ninth aspect of the invention, the flange portion of the bushing unit for power distribution equipment can be more firmly attached to the power distribution equipment. According to the invention of claim 10, it is possible to suppress the occurrence of corona discharge in the vicinity of the mounting bracket.

[Brief description of drawings]

FIG. 1 is a sectional view of a bushing unit according to a first embodiment.

FIG. 2 is a perspective view showing a zero-phase current transformer.

FIG. 3 is likewise an enlarged cross-sectional view for a zero-phase current transformer.

FIG. 4 is a sectional view taken along the line AA of FIG. 1, showing an arrangement position of the insulated wire.

FIG. 5 is a partial cross-sectional view showing a mounted state of the bushing unit in the first embodiment.

FIG. 6 is a sectional view of a bushing unit according to a second 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 mounted state of a bushing unit and an electric field near a mounting bracket in a third embodiment.

[Explanation of symbols]

1 ... Bushing unit, 2 ... Switch case (power distribution device), 3 ... Bushing body, 4 ... Flange part, 5, 5a
... d ... Insulation folds, 6 ... Zero phase current transformer, 7a, 7b ... Upper and lower cases, 8 ... Iron core parts, 11a-11c ... Insulated electric wires (insulating coated conductors), 13a-13c ... Connection conductor parts (penetration suppression means) , 17 ... Mounting bracket (flange fixing member), 20 ...
Mounting bolt (flange fixing member), 21 ... Washer (flange fixing member), 22 ... Tightening nut, 24, 2
6 ... Sealing ridges, 24, 27 ... Annular grooves, 25 ... Conductive rubber (conductive material).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kozo Kishimoto, Inuyama City, Aichi Prefecture, 1st small needle, Energy Support Co., Ltd. (72) Inventor, Tatsuya Kato, Inuyama City, Aichi Prefecture, 1st small character needle, Energy Support Co., Ltd.

Claims (10)

[Claims] 1. A bushing for a power distribution device, wherein one bushing body and a flange portion are integrally molded with an insulating polymer material, and three insulating coated conductors are arranged at the apexes of a triangle. A bushing unit for a three-phase package type power distribution device, characterized in that the bushing body is penetrated inside. 2. The power distribution device according to claim 1, wherein the insulation-coated conductor is an insulated wire, and infiltration preventing means for restricting movement of water inside the insulated wire is provided in the middle of each insulated wire. Bushing unit. 3. The bushing unit for power distribution equipment according to claim 1, wherein an iron core portion for a zero-phase current transformer is embedded in the flange portion. 4. The bushing unit for a power distribution device according to claim 3, wherein the iron core portion is accommodated in a case with a gap, and is embedded in that state. 5. The bushing unit for a power distribution device according to claim 1, wherein the insulating polymer material is ethylene propylene rubber or silicon rubber. 6. The bushing unit for a power distribution device according to claim 1, wherein a sealing ridge is integrally formed on a lower surface of the flange portion. 7. The bushing unit for a power distribution device according to claim 6, wherein the sealing ridge has an arcuate cross section. 8. The bushing unit for a power distribution device according to claim 6, wherein a plurality of the sealing ridges are formed. 9. A bushing body and a flange portion are integrally molded with an insulative polymer material, and three insulating coated conductors are respectively arranged at the apexes of a triangle so that the inside of the bushing body is covered. A three-phase batch type bushing unit for power distribution equipment in which a zero-phase current transformer is embedded in the flange portion is attached to the power distribution equipment by a flange fixing member. At least a part of the container is sandwiched between the flange part fixing member and the power distribution device via the flange part, and a mounting structure for a bushing unit for power distribution device. 10. A bushing body and a flange portion are integrally molded with an insulative polymer material, and three insulating coated conductors are respectively arranged at the vertices of a triangle so that the inside of the bushing body is covered. A mounting structure for mounting a penetrating bushing unit for a three-phase power distribution device to a power distribution device by a flange fixing member, wherein the flange fixing member has conductivity, and at least the flange is fixed. Mounting of a bushing unit for power distribution equipment, characterized in that a covering layer made of a conductive material is provided from an upper surface of the flange portion fixed by the member to an insulating fold provided at a position closest to the flange portion fixing member. Construction.