JP2009129855A - Vacuum circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control magnetic field interference given to arc generated between contacts, and to raise circuit break property. <P>SOLUTION: The vacuum circuit breaker uses a vacuum valve 1 including: a vacuum insulation container 2; a pair of attachable/detachable contacts 6, 7 contained in the vacuum insulation container 2; and current carrying axes 5, 8 adhered to the contacts 6, 7 respectively, and is characterized by forming a perimeter conductor 23 prepared so that the vacuum insulation container 2 may be surrounded, and connected with one of the current carrying axis 5, 8, and in which inverse current with the current carrying axis 5, 8 flows. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vacuum circuit breaker installed in an electric power system, and more particularly to a vacuum circuit breaker that can improve a breaking characteristic.

  In the power system, when a short-circuit accident or a ground fault occurs, a circuit breaker is installed to cut off the accident current and disconnect the accident point from the power system. As a circuit breaker having a system voltage of 3.3 kV to 66 kV, a vacuum circuit breaker using a vacuum valve having a pair of contact points that can be freely separated is often applied.

  As shown in FIG. 8, a fixed-side sealing fitting 3 and a movable-side sealing fitting 4 are sealed on both end opening surfaces of a cylindrical vacuum insulating container 2 constituting the vacuum valve 1. A fixed-side energizing shaft 5 is fixed through the fixed-side sealing metal fitting 3, and a fixed-side contact 6 is fixed to the end. Opposite to the fixed contact 6, a movable contact 7 that is detachable is fixed to the end of the movable energizing shaft 8 that movably penetrates the central opening of the movable seal 4. Further, an expandable / contractible bellows 9 is sealed between the opening of the movable side energizing shaft 8 and the movable side sealing fitting 4.

  As a result, the movable energizing shaft 8 moves in parallel with the axial direction along the guide 10 while keeping the inside of the vacuum insulating container 2 in a vacuum, so that the fixed contact 6 and the movable contact 7 can be contacted and separated. ing. A cylindrical arc shield 11 that surrounds the contacts 6 and 7 is fixed to a protruding portion that protrudes from an intermediate portion of the inner surface of the vacuum insulating container 2.

  As shown in FIG. 9, such a vacuum valve 1 is incorporated in a vacuum circuit breaker 12 having an operation mechanism (not shown). The lower main circuit of the vacuum circuit breaker 12 is connected to a main circuit disconnecting portion 13 a that is arranged orthogonal to the axial direction of the vacuum valve 1. An S-shaped connecting conductor 14 is connected to the main circuit disconnecting portion 13a, and a current transformer 15 and a transformer 16 are connected thereto. A power cable 17 is connected to the end of the connection conductor 14.

  The upper main circuit of the vacuum circuit breaker 12 is connected to a main circuit disconnecting portion 13b arranged orthogonal to the axial direction of the vacuum valve 1, similarly to the main circuit disconnecting portion 13a. A three-phase bus 19 is connected to the main circuit disconnecting portion 13b via an L-shaped connecting conductor 18 to be connected to an adjacent panel. These electric devices are accommodated in the box 20 (see, for example, Patent Document 1).

  In such a switchgear, when the power cable 17 is the power receiving side and the bus 19 is the load side, a current bent in a U-shape flows through the main circuit of the vacuum circuit breaker 12 as shown by the arrow in FIG. The valve 1 is also affected by this current.

Here, the vacuum valve 1 employs various electrode structures so as to control an arc between the contacts 6 and 7 and to interrupt a large current. In the spiral electrode and the control electrode, the arc is driven using an electromagnetic force generated between the current flowing in the electrode and the arc current, and the electrode is prevented from being melted by arc heat. In the longitudinal magnetic field electrode, by applying a magnetic field parallel to the arc, the arc is spread across the entire electrode, the arc voltage is lowered to suppress the arc energy, and the electrode is prevented from being melted.
Japanese Patent Laying-Open No. 2006-238581 (Page 4, FIG. 1)

  The conventional vacuum circuit breaker 12 has the following problems. Although the arc is controlled by adopting various electrode structures, the current flowing through the main circuit of the vacuum circuit breaker 12 is bent in a U shape, so that the Lorentz force is generated in the arc generated between the contacts 6 and 7. In addition, it may be difficult to control the arc. That is, the arc is affected by the external magnetic field due to the bent current path, and the arc is difficult to be generated at a uniform density, and is generated at a biased position on the electrode surface, which may deteriorate the interruption characteristics.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a vacuum circuit breaker capable of suppressing the influence of an external magnetic field on an arc and improving the breaking characteristics.

  In order to achieve the above object, a vacuum circuit breaker according to the present invention comprises a vacuum insulating container, a pair of contactable and separable contacts housed in the vacuum insulating container, and a current-carrying shaft fixed to each of the contacts. A vacuum circuit breaker using a vacuum valve having an outer peripheral conductor connected to one of the current-carrying shafts and provided to surround the vacuum insulating container.

  According to the present invention, since the outer peripheral conductor surrounding the vacuum insulating container is provided on the outer periphery of the vacuum valve, the direction of the current flowing through the current-carrying shaft on the fixed side and the movable side is opposite to the direction of the current flowing through the outer peripheral conductor. Therefore, the magnetic field generated between the contacts is canceled out, the influence of the external magnetic field on the arc can be suppressed, and the interruption characteristic can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a vacuum circuit breaker according to Embodiment 1 of the present invention will be described with reference to FIG. 1 is a cross-sectional view showing a configuration of a vacuum valve used in a vacuum circuit breaker according to Embodiment 1 of the present invention. In FIG. 1, the same components as those in the prior art are denoted by the same reference numerals. Further, since the vacuum circuit breaker incorporating the vacuum valve and the switch gear for housing the vacuum circuit breaker are the same as the conventional one, the description thereof is omitted.

  As shown in FIG. 1, a fixed-side sealing metal fitting 3 and a movable-side sealing metal fitting 4 are sealed to both end opening surfaces of a cylindrical vacuum insulating container 2 made of alumina porcelain constituting a vacuum valve 1. Yes. A fixed-side energizing shaft 5 is fixed through the fixed-side sealing metal fitting 3, and a fixed-side contact 6 is fixed to the end. Opposite to the fixed contact 6, a movable contact 7 that is detachable is fixed to the end of the movable energizing shaft 8 that movably penetrates the central opening of the movable seal 4. Further, between the opening of the movable side energizing shaft 8 and the movable side sealing metal fitting 4, both ends of the expandable bellows 9 are sealed.

  As a result, the movable energizing shaft 8 moves in parallel with the axial direction along the guide 10 while keeping the inside of the vacuum insulating container 2 in a vacuum, so that the fixed contact 6 and the movable contact 7 can be contacted and separated. ing. A cylindrical arc shield 11 that surrounds the contacts 6 and 7 is fixed to a protruding portion that protrudes from an intermediate portion of the inner surface of the vacuum insulating container 2.

  The movable energizing shaft 8 outside the vacuum insulating container 2 is provided with a disk-like lower conductor 22 via an annular and sliding contact 21 at the center. A cylindrical outer conductor that is provided on the outer peripheral portion of the lower conductor 22 so as to surround the vacuum insulating container 2, has an inner diameter larger than the outer diameter of the vacuum insulating container 2, and maintains an interval capable of withstanding a predetermined voltage. One end of 23 is connected. A connection terminal 24 is provided on one side surface of the other end of the outer conductor 23. A main circuit conductor of a vacuum circuit breaker (not shown) is connected to the connection terminal 24 and the end of the fixed side energizing shaft 5.

  When a current flows from the fixed side, the current path is fixed side energizing shaft 5 → fixed side contact 6 → movable side contact 7 → movable side energizing shaft 8 → lower conductor 22 → outer peripheral conductor 23. As the current flows in this way, the current flowing through the fixed-side energizing shaft 5 and the movable-side energizing shaft 8 flows through the center of the coaxial line, and the current flowing through the outer conductor 23 flows through the outer periphery of the coaxial line whose direction is opposite. Will flow. Similarly, when a current flows from the movable side, the current direction is reversed between the central portion and the outer peripheral portion.

  For this reason, the external magnetic field generated between the fixed contact 6 and the movable contact 7 cancels out at the center and the outer periphery of the coaxial line, and the external magnetic field generated by bending the current in a U-shape as in the prior art. The influence can be suppressed. As a result, the arc control by the spiral electrode, the control electrode, the longitudinal magnetic field electrode and the like is ensured, and the interruption characteristic can be improved. If the outer peripheral conductor 23 is arranged coaxially with respect to each of the fixed-side energizing shaft 5, the fixed-side contact 6, the movable-side contact 7, and the movable-side energizing shaft 8, the influence of the external magnetic field can be further suppressed.

  According to the vacuum circuit breaker of the first embodiment, since the outer peripheral conductor 23 surrounding the vacuum insulating container 2 is connected to the movable side energizing shaft 8, the fixed side energizing shaft 5 and the movable side energizing shaft 8 are connected to each other. The direction of the flowing current and the direction of the flowing current in the outer conductor 23 are opposite to each other, so that the magnetic field generated between the fixed contact 6 and the movable contact 7 is canceled out, and the influence of the external magnetic field on the arc can be suppressed. , The cut-off characteristics can be improved.

  Next, a vacuum circuit breaker according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating a configuration of a vacuum valve used in the vacuum circuit breaker according to the second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the outer peripheral conductor is subjected to insulation reinforcement. In FIG. 2, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, a cylindrical first insulating cylinder 25 made of an insulating material is inserted between the vacuum insulating container 2 and the outer peripheral conductor 23, and a cylindrical second is also formed on the outer periphery of the outer peripheral conductor 23. Insulating cylinder 26 is provided.

  As a result, the first insulating cylinder 25 is externally insulated from the vacuum insulating container 2, and the second insulating cylinder 26 is reinforced by insulating material from the external insulation of the outer peripheral conductor 23. With the first insulating cylinder 25, the outer peripheral conductor 23 can be disposed close to the vacuum insulating container 2, and the outer diameter of the lower conductor 22 can be reduced. For this reason, the current path flowing through the lower conductor 22 is shortened, and the outer peripheral conductor 23 can be disposed close to the vacuum insulating container 2, so that the influence of the external magnetic field applied between the fixed side contact 6 and the movable side contact 7 is reduced. It can be suppressed more. Further, the insulation distance between the phases and the ground can be reduced by the second insulating cylinder 26.

  According to the vacuum circuit breaker of the second embodiment, in addition to the effects of the first embodiment, the influence of the external magnetic field can be further suppressed, and the overall shape of the vacuum circuit breaker can be reduced.

  Next, a vacuum circuit breaker according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a configuration of a vacuum valve used in a vacuum circuit breaker according to Embodiment 3 of the present invention. The third embodiment differs from the second embodiment in that the vacuum insulating container and the outer peripheral conductor are molded integrally. In FIG. 3, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, the outer periphery of the vacuum insulating container 2 and the outer peripheral conductor 23 are integrally molded with an insulating resin 27 such as an epoxy resin. At the time of molding, the outer periphery of the vacuum insulating container 2 and the surface of the outer peripheral conductor 23 are degreased to improve the adhesion with the insulating resin 27, so that the insulating properties at these interfaces are improved.

  Note that only the space between the vacuum insulation container 2 and the outer conductor 23 may be molded. In the same manner as in the second embodiment, the external insulation of the vacuum insulation container 2 and the outer conductor 23 is insulated and reinforced with an insulating material. .

  According to the vacuum circuit breaker of the third embodiment, the same effect as that of the second embodiment can be obtained.

  Next, a vacuum circuit breaker according to Embodiment 4 of the present invention will be described with reference to FIGS. 4 and 5 are top views showing the configuration of the vacuum valve used in the vacuum circuit breaker according to Embodiment 4 of the present invention. The fourth embodiment is different from the first embodiment in the shape of the conductor provided on the outer periphery of the vacuum valve. 4 and 5, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, on the outer periphery of the vacuum insulating container 2, a plurality of rod-shaped outer peripheral bar conductors 28 are provided at substantially equal intervals in the circumferential direction at a predetermined distance from the vacuum insulating container 2. One end of the outer peripheral bar conductor 28 is connected to the lower conductor 22, and the other end is connected to an annular ring conductor 30 provided with a connection terminal 29. The plurality of outer peripheral bar conductors 28 correspond to the outer peripheral conductors of the first embodiment.

  Further, as shown in FIG. 5, the outer peripheral bar conductor 28 is provided with an insulating coating 31 which is molded with an insulating material or covered with an insulating tube. The vacuum insulating container 2 and the outer peripheral bar conductor 28 may be integrally molded with an insulating material.

  According to the vacuum circuit breaker of the said Example 4, the effect similar to Example 1 can be acquired.

  Next, a vacuum circuit breaker according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 6: is sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker concerning Example 5 of this invention. The fifth embodiment differs from the first embodiment in that an outer peripheral conductor is provided on the movable side. In FIG. 6, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, a disk-shaped upper conductor 32 is fixed to the end of the fixed side energizing shaft 5 with a bolt 33. One end of a cylindrical outer conductor 34 is connected to the outer periphery of the upper conductor 32 so as to surround the vacuum insulating container 2, and a connection terminal 35 is provided on one side of the other end. Further, a lower conductor 36 is provided on the movable side energizing shaft 8 via a contact 21. A main circuit conductor of a vacuum circuit breaker (not shown) is connected to the connection terminal 35 and the lower conductor 36 end.

  When a current flows from the fixed side, the current path is as follows: outer peripheral conductor 34 → upper conductor 32 → fixed side energizing shaft 5 → fixed side contact 6 → movable side contact 7 → movable side energized shaft 8 → lower conductor 36. As the current flows in this way, the current flowing through the fixed-side energizing shaft 5 and the movable-side energizing shaft 8 flows through the center of the coaxial line, and the current flowing through the outer conductor 34 passes through the outer periphery of the coaxial line in the opposite direction. Will flow. Similarly, when a current flows from the movable side, the current direction is reversed between the central portion and the outer peripheral portion.

  According to the vacuum circuit breaker of the fifth embodiment, the same effect as that of the first embodiment can be obtained.

  Next, a vacuum circuit breaker according to Embodiment 6 of the present invention will be described with reference to FIG. FIG. 7: is sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker concerning Example 6 of this invention. The sixth embodiment differs from the first embodiment in that outer peripheral conductors are provided on the fixed side and the movable side. In FIG. 7, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, a cylindrical upper conductor 32 is fixed to the end of the fixed energizing shaft 5 with a bolt 33, and a cylindrical shape that surrounds up to the middle portion of the vacuum insulating container 2 on the outer periphery thereof. One end of the fixed outer peripheral conductor 37 is connected. A connection terminal 38 is provided on one side surface of the other end. Further, the movable energizing shaft 8 is provided with a disk-shaped lower conductor 22 via a contact 21, and a cylindrical movable outer peripheral conductor that surrounds up to an intermediate portion of the vacuum insulating container 2 on the outer peripheral portion thereof. One end of 39 is connected. A connection terminal 40 is provided on one side surface of the other end. The end of the fixed outer conductor 37 and the end of the movable outer peripheral conductor 39 face each other, and maintain an interval that can withstand a predetermined voltage. A main circuit conductor of a vacuum circuit breaker (not shown) is connected to the connection terminal 38 and the connection terminal 40, respectively.

  When the current flows from the fixed side, the current path is as follows: fixed outer peripheral conductor 37 → upper conductor 32 → fixed side energizing shaft 5 → fixed side contact 6 → movable side contact 7 → movable side energized shaft 8 → lower conductor 22 → It becomes the movable side outer peripheral conductor 39. As a result of the current flowing in this way, the current flowing through the fixed-side energizing shaft 5 and the movable-side energizing shaft 8 flows through the center of the coaxial line, and the current flowing through the outer conductors 37 and 39 is the outer periphery of the coaxial line whose direction is reversed. Will flow through the part. Similarly, when a current flows from the movable side, the current direction is reversed between the central portion and the outer peripheral portion.

  Although the arc shield 11 has an intermediate potential, the fixed outer peripheral conductor 37 and the movable outer peripheral conductor 39 are disposed close to each other, so that the potential is brought close to 50% between the main circuit potential and the ground potential. be able to. Thereby, the potential sharing in the vacuum valve 1 is improved, and the cutoff characteristic and the withstand voltage characteristic can be improved.

  Insulating cylinders are provided between the fixed outer peripheral conductor 37, the movable outer peripheral conductor 39 and the vacuum insulating container 2, and the outer periphery of the fixed outer peripheral conductor 37 and the movable outer peripheral conductor 39. If the insulation reinforcement is performed, the influence of the external magnetic field can be further suppressed, and the overall shape of the vacuum circuit breaker can be reduced.

  According to the vacuum circuit breaker of the sixth embodiment, in addition to the same effect as that of the first embodiment, the electric field distribution in the vacuum valve 1 can be improved.

Sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 1 of this invention. Sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 2 of this invention. Sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 3 of this invention. The top view which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 4 of this invention. The top view which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 4 of this invention. Sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 5 of this invention. Sectional drawing which shows the structure of the vacuum valve used for the vacuum circuit breaker which concerns on Example 6 of this invention. Sectional drawing which shows the structure of the vacuum valve used for the conventional vacuum circuit breaker. The side view which shows the structure of a switchgear.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum valve 2 Vacuum insulation container 3 Fixed side sealing metal fitting 4 Movable side sealing metal fitting 5 Fixed side energizing shaft 6 Fixed side contact 7 Movable side contact 8 Movable side energizing shaft 9 Bellows 10 Guide 11 Arc shield 12 Vacuum circuit breaker 13a, 13b Main circuit disconnection parts 14 and 18 Connection conductor 15 Current transformer 16 Transformer 17 Power cable 19 Bus 20 Box body 21 Contacts 22 and 36 Lower conductors 23 and 34 Outer conductors 24, 29, 35, 38, 40 Connection terminal 25 First insulating cylinder 26 Second insulating cylinder 27 Insulating resin 28 Outer rod conductor 30 Ring conductor 31 Insulation coating 32 Upper conductor 33 Bolt 37 Fixed outer peripheral conductor 39 Moving outer peripheral conductor

Claims (7)

A vacuum insulation container;
A pair of detachable contacts housed in the vacuum insulating container;
A vacuum circuit breaker using a vacuum valve having a current-carrying shaft fixed to each of the contacts,
A vacuum circuit breaker provided to surround the vacuum insulating container and provided with an outer peripheral conductor connected to one of the energizing shafts.   The vacuum circuit breaker according to claim 1, wherein the outer peripheral conductor is a cylindrical conductor.   The vacuum circuit breaker according to claim 1, wherein the outer peripheral conductor is a plurality of rod-shaped conductors.   The vacuum circuit breaker according to any one of claims 1 to 3, wherein the external insulation of the vacuum insulating container is insulated and reinforced with an insulating material.   The vacuum circuit breaker according to any one of claims 1 to 4, wherein the outer insulation of the outer peripheral conductor is insulated and reinforced with an insulating material. A vacuum insulation container;
A pair of detachable contacts housed in the vacuum insulating container;
A vacuum circuit breaker using a vacuum valve having a fixed-side energizing shaft and a movable-side energizing shaft respectively fixed to the contacts;
A fixed-side outer peripheral conductor connected to the fixed-side energizing shaft and provided so as to surround up to an intermediate portion of the vacuum insulating container;
A movable outer peripheral conductor is provided so as to surround up to an intermediate portion of the vacuum insulating container, and is opposed to the fixed outer peripheral conductor at a predetermined interval, and is connected to the movable energizing shaft. A vacuum circuit breaker characterized by that.   The vacuum circuit breaker according to claim 6, wherein external insulation of the vacuum insulating container, the fixed outer peripheral conductor and the movable outer peripheral conductor is insulated and reinforced with an insulating material.

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