WO2012066792A1

WO2012066792A1 - Bushing

Info

Publication number: WO2012066792A1
Application number: PCT/JP2011/052264
Authority: WO
Inventors: 稲葉　繁; 圭二後藤
Original assignee: 三菱電機株式会社
Priority date: 2010-11-18
Filing date: 2011-02-03
Publication date: 2012-05-24
Also published as: JP5089830B2; JPWO2012066792A1; TW201223046A; TWI423546B

Abstract

A bushing provided on the rear wall surface a stationary frame (1), on which a switch device is mounted, so as to penetrate through the rear wall surface and forming a main circuit disconnection section. The insulation tube (12) of the bushing (10) has: a tube section (12a); a flange section (12b) affixed to the wall surface; and a mounting section (12c) located near the front end-side opening end of the tube section (12a) and having a center conductor (13) mounted thereto. The center conductor (13) has: a terminal connection section (13a) which protrudes to the inside of the tube section (12a) and to which the main circuit terminal of the switch device is connected; and a main circuit connection section (13b) which is mounted to the mounting section (12c) and to the outer end surface of which a main circuit conductor, such as a bus line, is connected. Ventilation holes (14a, 14b) penetrating through the main circuit connection section (13b) in the direction perpendicular to the axis of the center conductor (13) are provided on the mounting section (12c) side of the main circuit connection section (13b).

Description

Bushing

The present invention relates to a bushing portion that is provided on the back side of a switching device such as a vacuum circuit breaker that can be pulled out in a casing of a switchboard, and that serves as a main circuit disconnecting portion. is there.

The current energization part of the main circuit of the apparatus to which a vacuum circuit breaker or the like is connected must have a temperature rise value when the rated current is energized to a predetermined value or less according to the standard. Also, from the viewpoint of safety (protection class), most of the equipment is boxed or bulkheaded to protect people who cannot access dangerous parts or to protect the equipment from solid foreign objects entering the equipment. Etc. For this reason, in the energization part of a main circuit, the structural consideration which satisfy | fills the conditions of a temperature rise value is needed.
For example, as shown in FIG. 7, the conventional structure in consideration of the temperature rise of the main circuit disconnection portion has a rectangular small cylindrical portion 21 a and a large diameter on one side of the insulating layer 21 through which the center conductor 20 is inserted. The cylindrical portion 21b is provided so as to protrude coaxially. Among these, the vent portion 23 is provided on the upper and lower sides of the cylindrical portion 21a corresponding to the position facing the fitting portion between the contact 22 and the center conductor 20, The cylindrical portion 21b is provided with vents 24 at the front upper and lower sides so as to increase the cooling effect by using the convection of the cooling gas heated by the heat generated from the contact portion between the contact 22 and the central conductor 20. Have been disclosed (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-322819 (page 3, FIG. 1-2)

In a conventional main circuit disconnection portion (hereinafter referred to as a bushing) as described in Patent Document 1, a vent is provided in a direction perpendicular to the side surface of each cylindrical portion protruding from the insulating layer 21. For example, when the insulating layer 21 is manufactured by casting, there is a problem that the structure of the mold becomes complicated and the processing takes time and cost.
In addition, the shape described in Patent Document 1 has a structure in which air is circulated only on the connection portion side to which a contact such as a circuit breaker is connected. Therefore, only the connection portion side is cooled. However, there is a problem that the temperature rise on the opposite side, that is, the side to which the main circuit conductor such as the bus is connected cannot be suppressed.

The present invention has been made to solve the above-described problems, and an object thereof is to obtain a bushing that can suppress a temperature rise during energization with a simple configuration and has an excellent cooling effect.

The bushing according to the present invention has an insulating cylinder and a central conductor inserted through the center of the fixed frame on which the switchgear is placed, and has one end of the central conductor. In the bushing in which the main circuit terminal of the switchgear is connected to the other end and the main circuit conductor is connected to the other end, the insulating tube includes a tube portion and a flange portion on one end side of the tube portion and fixed to the wall surface. A mounting portion in the vicinity of the opening end on the other end side to which the central conductor is attached, and the central conductor projects from the mounting portion to the inside of the cylindrical portion and is connected to the terminal connection portion to which the main circuit terminal is connected. And a main circuit connection portion to which the main circuit conductor is connected to the outer end surface, and a vent hole penetrating in a direction orthogonal to the axis of the central conductor is provided on the attachment portion side of the main circuit connection portion. It is what.

According to the bushing of this invention, the insulating cylinder of the bushing has a cylindrical portion, a flange portion that is fixed to the wall surface at one end side of the cylindrical portion, and a central conductor that is near the opening end on the other end side. A central conductor that projects from the mounting portion to the inside of the cylindrical portion and is connected to the main circuit terminal; and a main circuit conductor that is attached to the mounting portion and connected to the outer end surface. Since the vent hole penetrating in the direction perpendicular to the axis of the central conductor is provided on the mounting part side of the main circuit connection part, the current-carrying part can be directly cooled with a simple configuration. Therefore, it is possible to efficiently cool the bushing portion while suppressing the temperature rise of the energization portion.

It is side surface sectional drawing which shows the main circuit disconnection part of the vacuum circuit breaker to which the bushing by Embodiment 1 of this invention was applied. It is a perspective view for demonstrating the structure of the bushing of FIG. It is side surface sectional drawing of the bushing of FIG. It is explanatory drawing explaining the flow of the air of the wall surface using the bushing of Embodiment 1. FIG. It is a perspective view of the bushing by Embodiment 2 of this invention. It is side surface sectional drawing of the bushing of FIG. It is side surface sectional drawing of the conventional bushing.

Embodiment 1 FIG.
Hereinafter, a bushing according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a side sectional view showing a state in which a bushing is disposed on the back surface of a fixed frame in which a vacuum circuit breaker is accommodated, and the vacuum circuit breaker is connected to the bushing. 2 is a perspective view showing the bushing portion of FIG. 1, and FIG. 3 is a side sectional view of FIG.

Here, the bushing used for the connection part (disconnection part) of a vacuum circuit breaker and the main circuit conductor by the side of a switchboard is described as an example of the switchgear accommodated in a switchboard.
The inside of a casing (not shown) constituting the switchboard is partitioned into a circuit breaker room in which a circuit breaker is accommodated, a bus room in which a bus is accommodated, a cable room in which a cable is accommodated, and the like. As shown in FIG. 1, the vacuum circuit breaker 2 disposed in the fixed frame 1 constituting the circuit breaker chamber includes a carriage 3 having wheels and movable in the front-rear direction, and an insulating frame fixed on the carriage 3. 4, a vacuum valve 5 housed therein, and a drive mechanism (see FIG. 4) that is connected to a movable contact (not shown) of the vacuum valve 5 and that contacts and separates the movable contact from a fixed contact (not shown). Not shown). Further, the upper main circuit terminal 6 is led out from the fixed side contact, and the lower main circuit terminal 7 is led out from the movable side contact and fixed to the insulating frame 4 respectively. For example, a finger-shaped contact 8 as described later is provided at the tip of each

main circuit terminal

6, 7.

An upper bushing 10 and a lower bushing 11 are provided through the wall surface of the fixed frame 1 located on the back side of the vacuum circuit breaker 2 so as to face the upper main circuit terminal 6 and the lower main circuit terminal 7.
FIG. 1 shows a state in which the upper and lower

main circuit terminals

6 and 7 of the vacuum circuit breaker 2 and the upper and

lower bushings

10 and 11 are connected. From this connected state, the vacuum circuit breaker 2 is moved together with the carriage 3 to the front surface. If it is pulled out to the side, it will be in a disconnected state, and it can be taken out of the panel from the front of the casing.

2 is a perspective view showing the bushing structure of FIG. 1, and FIG. 3 is a side sectional view thereof. Since the upper bushing 10 and the lower bushing 11 have basically the same shape, the upper bushing 10 will be described below as an example.
2 and 3, the upper bushing 10 includes, for example, an insulating cylinder 12 made of an insulating material such as an epoxy resin, and a center conductor 13 inserted through the center thereof.
The insulating tube 12 includes a rectangular tube portion 12a, a rectangular flange portion 12b provided on one opening end side of the tube portion 12a and attached to the fixed frame 1, and a tube portion on the inner side near the other opening end. And a mounting portion 12c provided in a direction perpendicular to the axis 12a to which the central conductor 13 is mounted.

The center conductor 13 protrudes from the mounting portion 12c to the inside of the cylindrical portion 12a, and is connected to the cylindrical terminal connection portion 13a to which the upper main circuit terminal 6 of the vacuum circuit breaker 2 is connected, and to the outer end surface. A main circuit connection portion 13b to which a main circuit conductor such as a bus or a cable (not shown) is connected (on the opposite side of the mounting surface) is provided. (The inside of the tube portion from the attachment surface to the attachment portion 12c is the terminal connection portion 13a, and the opening side is the main circuit connection portion 13b.)
The terminal connection part 13a and the main circuit connection part 13b may be manufactured by the same member, or individually manufactured parts may be joined by brazing or the like.

As shown in FIG. 3, a finger-shaped contact 8 is provided on the distal end side of the upper main circuit terminal 6 on the vacuum circuit breaker 2 side, and the terminal connection portion 13 a of the center conductor 13 is connected to the contact 8. And is electrically connected by sliding contact.
The contact 8 has a plurality of contact pieces 8a formed in an annular shape on the outer periphery of the tip end of the upper main circuit terminal 6 and the lower main circuit terminal 7 of the vacuum circuit breaker 2, and has an inner diameter by an annular spring 8b provided on the outer peripheral side. Is biased in the direction. With this spring force, one convex portion on the inner peripheral side of the contact piece 8a is brought into contact with the outer periphery of the terminal connecting portion 13a of the center conductor 13 by applying a contact load.

The feature of the present application is that a vent hole is provided in the main circuit connection portion 13b of the central conductor 13 and a communication port is provided in the terminal connection portion 13a.
The vent is opened in a direction orthogonal to the axis of the central conductor 13 (that is, in a direction parallel to the mounting surface of the mounting portion 12c), and as shown in FIGS. The vent hole 14b penetrating in the direction is formed in a cross shape and connected at the center. When the terminal connection portion 13a and the main circuit connection portion 13b are manufactured as separate members, the vent holes 14a and 14b may be provided with a U-shaped groove on the mounting surface side of the main circuit connection portion 13b.
Further, as shown in the side sectional view of FIG. 3, a communication port 14c is formed which communicates from the central portion of the

vent holes

14a, 14b to the inner side of the cylindrical portion 12a with the center of the terminal connection portion 13a directed in the axial direction. ing.

Next, the operation of the

vents

14a and 14b and the communication port 14c of the bushing configured as described above will be described.
The temperature of the vacuum circuit breaker and the main circuit conductor rises due to the generation of Joule heat caused by energization. However, since the inside of the vacuum circuit breaker and the main circuit conductor must be protected so that no one can approach them and solid foreign objects do not enter, most of the whole is covered in some form. It has been broken. Therefore, the heat dissipation effect is low, and consideration for satisfying the condition of the temperature rise value is necessary.
Therefore, in the present invention, as described above, the vent holes 14a and 14b and the communication port 14c are provided in the central conductor 13 of the bushing 10.
The temperature of the bushing 10 rises due to the current flowing through the central conductor 13 of the bushing 10, but the air is sucked and exhausted from the

vents

14 a and 14 b, the main circuit connection 13 b is cooled, and the terminals are connected by heat conduction. The part 13a side is also cooled.

Furthermore, by providing the communication port 14c, as shown in FIG. 4, the communication port 14c is connected to the

vent ports

14a and 14b, and the air flow from the back side of the fixed frame 1 to the housing side of the vacuum circuit breaker 2 is achieved. Since the path is formed, for example, air flows as indicated by an arrow, and the connection portion between the terminal connection portion and the contact of each main circuit terminal can be directly cooled.

Further, the air inside the circuit breaker chamber can be sucked and exhausted through the upper and

lower bushings

10, 11, and a higher cooling effect can be obtained.
Furthermore, the central conductor 13 itself, which is a current-carrying part, is provided with a vent and a communication port, both of which are opened in a direction in which human fingers etc. are not accessible, so that the safety (protection class) of the current-carrying part is satisfied However, it is possible to simultaneously satisfy the safety (protection class) of the vent and the communication port for intake and exhaust of air.

In the above description, the shape of the main circuit connecting portion 13b of the central conductor 13 is rectangular when viewed in the axial direction, but is not limited to this and may be circular. In that case, the cylinder part 12a may also be a cylinder.
In addition, although two vent holes (14a, 14b) are provided in the horizontal direction and the vertical direction, either one may be provided.
Furthermore, although the communication port 14c is provided at the center of the terminal connection portion 13a, this communication port 14c may not be provided when the energization capacity is small.

As described above, according to the bushing of the first embodiment, the insulating cylinder and the center conductor inserted through the center of the insulating cylinder are inserted through the wall on the back side of the fixed frame on which the switchgear is placed. In the bushing in which the main circuit terminal of the switchgear is connected to one end portion of the center conductor and the main circuit conductor is connected to the other end portion, the insulating cylinder is located on one end side of the tube portion and the tube portion. It has a flange part fixed to the wall surface and an attachment part near the opening end on the other end side to which the central conductor is attached. The central conductor projects from the attachment part to the inside of the cylindrical part and connects to the main circuit terminal. A terminal connection portion that is connected to the mounting portion and a main circuit connection portion that is connected to the outer end surface of the main circuit conductor, and a direction orthogonal to the axis of the central conductor on the mounting portion side of the main circuit connection portion The vents that penetrate the In order to be able, it can be cooled efficiently bushing portion by suppressing the temperature rise of the energization part.

In addition, since the air vent is formed in a cross shape in the horizontal and vertical directions, air from outside can be effectively sucked and exhausted inside the central conductor of the bushing, so a high cooling effect is achieved. Obtainable.

Furthermore, since a communication port is provided in the center of the terminal connection portion of the center conductor from the ventilation port to the inside of the tube portion, the air on the switchgear side can be sucked and exhausted through the bushing, especially the temperature Since the terminal contact portion where the rise is high can be effectively cooled, a high cooling effect can be obtained while suppressing the temperature rise of the energization portion.

Embodiment 2. FIG.
FIG. 5 is a perspective view of a bushing according to Embodiment 2 of the present invention, and FIG. 6 is a side sectional view thereof. Since the connection structure with the switchgear side including the vacuum circuit breaker 2 arranged in the fixed frame 1 is the same as that in FIG. 1 of the first embodiment, the illustration and description are omitted, and the difference will be mainly described.

The connection conductor of the electrical equipment constituting the switchboard must withstand the rated current, rated short-time withstand current and rated peak withstand current. In addition, the insulating support portion of the connection conductor must have a support structure that can sufficiently withstand electromagnetic force when a short-circuit current is energized and impact force when opening and closing. For these reasons, it is necessary to secure a sufficient cross-sectional area even in the central conductor of the bushing, to fix it firmly, and to be able to withstand energization and impact force.

In the structure shown in FIGS. 2 and 3 described in the first embodiment, a sufficient cooling effect can be expected. However, from the above viewpoint, there may be a need for further contrivance.
Therefore, in the second embodiment, as shown in FIGS. 5 and 6, the vent provided in the central conductor 13 of the upper bushing 10 is, for example, only the vent 14 a provided in the direction perpendicular to the mounting surface of the main circuit connection portion 13 b. Instead of this, ventilation slits 15 penetrating in the direction parallel to the axis of the center conductor 13 are provided at four places on the left and right and up and down outside the outer periphery of the main circuit connecting portion 13b of the mounting portion 12c of the insulating cylinder 12. . The ventilation slit 15 can satisfy the condition of safety (protection grade) by setting the size (width) so that a part of the human body (such as a finger) does not enter.

Next, the operation of this configuration will be described.
By limiting the vent hole provided in the central conductor 13 of the bushing to, for example, the vent hole 14a to a minimum, the current capacity and the strength of the support portion (joint portion between the terminal connection portion 13a and the main circuit connection portion 13b) are almost increased. The center conductor 13 is cooled without sacrificing, and the bushing 10 (and 11) is provided by the ventilation slit 15 penetrating the mounting portion 12c of the insulating cylinder 12 as described in FIG. 4 of the first embodiment. ), The air flow path between the vacuum circuit breaker side and the main circuit conductor side is formed, so that air in and out of the insulating frame 4 of the vacuum circuit breaker 2 can be taken in and out. A high cooling effect can be obtained.
Further, the ventilation slit 15 provided in the mounting portion 12c of the insulating cylinder 12 is formed in the axial direction of the insulating cylinder 12 (the removal direction of the forming process). It can be done inexpensively.

In the above description, the ventilation slits 15 are provided at four positions on the left and right and upper and lower sides of the main circuit connecting portion 13b.
Further, the vent hole provided in the central conductor 13 may be in the horizontal direction, and may have two places in the vertical direction and the horizontal direction as in the first embodiment as long as there is a structural (and electrical) margin. You may provide a communicating port in the center of the terminal connection part 13a.

As described above, according to the bushing of the second embodiment, in addition to the configuration of the first embodiment, the ventilation slit penetrating in the axial direction of the central conductor is provided in the mounting portion of the insulating cylinder. In addition to the effect of the first aspect, the intake and exhaust of the air on the switching device side can be performed, and a higher cooling effect can be obtained.
Further, by keeping the vent hole provided in the center conductor to a minimum, it is possible to provide a bushing having an excellent cooling effect while ensuring the current capacity of the center conductor and the strength of the support portion.
In addition, since the ventilation slit is provided in the axial direction of the insulating cylinder, the insulating cylinder can be easily manufactured by molding without requiring any special additional processing.

Claims

A switch frame is provided on the back wall of the fixed frame on which the switchgear is mounted, and has an insulating tube and a center conductor inserted through the center thereof. In the bushing where the circuit terminal is connected and the main circuit conductor is connected to the other end,
The insulating tube includes a tube portion, a flange portion that is fixed to the wall surface at one end side of the tube portion, and a mounting portion that is near the opening end on the other end side and to which the center conductor is attached. ,
The central conductor protrudes from the mounting portion to the inside of the cylindrical portion and is connected to the main circuit terminal, and the main circuit is connected to the mounting portion and the main circuit conductor is connected to the outer end surface. Having a connection part,
A bushing characterized in that a vent hole penetrating in a direction orthogonal to the axis of the central conductor is provided on the mounting portion side of the main circuit connecting portion.
The bushing according to claim 1, wherein
The bushing characterized in that the vent is formed in a cross shape in the horizontal direction and the vertical direction.
The bushing according to claim 1 or claim 2,
A bushing characterized in that a communication port is provided in the center of the terminal connection portion of the central conductor so as to communicate from the ventilation port to the inside of the cylindrical portion.
The bushing according to claim 1 or claim 2,
A bushing characterized in that a ventilation slit penetrating in the direction of the axis is provided in the mounting portion of the insulating cylinder.