JP3758435B2 - Power switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power switch using a vacuum switch, and more particularly to a power switch in which a plurality of vacuum switches are integrated.
[0002]
[Prior art]
The closed type switchboard used to receive power from the busbar and distribute it to various load devices and other electrical systems includes the busbar side conductor for connection to the busbar, the load side conductor for connection to the power transmission cable to the load, etc. The main circuit switch that connects and disconnects the bus-side conductor and the load-side conductor, the ground switch for grounding the load-side conductor, and control devices required for monitoring and control Arranged in a box.
Japanese Patent Publication No. 7-28488 discloses a ring in which a main circuit switch and a ground switch, which are main internal devices in a closed type switchboard whose configuration is shown in FIG. There is a description of the main switchgear.
[0003]
This ring main switchgear includes a vacuum switch, which is a main circuit switch, three disconnectors having a grounding electrode, and a connection conductor connecting them, and penetrates the peripheral wall of the container. It is configured to be connected to a distribution network via a pair of bushings, and this is used to reduce the size of a closed type distribution board applied to a ring network.
[0004]
However, in the ring main switch as described above, the vacuum switch only opens and closes the main circuit, and the three disconnectors disconnect from the distribution network and ground the disconnected circuit conductor. The required insulation distance is defined by the voltage class of the gas, the insulating gas to be sealed, and the pressure, and the arrangement of each component is naturally determined by the connection relationship of each component. If the internal insulating gas is short-circuited, the enclosed insulating gas may become high temperature and high pressure, so the container must be equipped with a pressure release mechanism that can withstand the pressure rise of the insulating gas and release this internal pressure. There is a problem that the structure is complicated and the cost increases.
[0005]
In order to solve the above problems, the present inventor previously disclosed a flexible conductor for electrically connecting a main circuit switching unit, a ground switching unit, and respective load side electrodes in Japanese Patent Application No. 11-95583. A composite vacuum switch is housed in a vacuum container, and one circuit and three phases of this composite vacuum switch are integrated by casting an insulating resin to provide power switching with the same functions as the ring main switching device described above. A vessel is proposed.
[0006]
[Problems to be solved by the invention]
The composite vacuum switch that constitutes the power switch described above is connected to the main circuit switching part and ground in a vacuum vessel formed by joining metal vacuum vessel parts by brazing to the end face of an insulating cylinder using ceramic or the like. An opening / closing part is enclosed. Since the joint portion of the vacuum vessel is formed by forming a metal layer on the end face of the insulating cylinder by metalizing and brazing the metal layer and the metal vacuum vessel part, the mechanical strength is the lowest in the vacuum vessel. Various measures are taken so that the joint portion of the vacuum vessel is not damaged by compressive stress due to curing shrinkage of the insulating resin layer in which a plurality of composite vacuum switches are integrated or thermal stress due to energization. Further, since an edge is formed by the metalizing metal layer and the braze fillet portion on the end surface of the insulating cylinder at the joint portion of the vacuum vessel, it is necessary to take measures for preventing discharge due to electric field concentration.
An object of the present invention is to more rationally realize prevention of mechanical damage at a joint portion of a vacuum vessel and prevention of discharge due to electric field concentration. It also aims to improve the productivity and realize a more compact power switch.
[0007]
[Means for Solving the Problems]
The power switch according to the present invention covers the corner of the outer peripheral end of the insulating cylinder at one end, the outer periphery of the metal vacuum vessel component at the other end, and the end corner on the side covering the corner of the outer peripheral end of the insulating cylinder. A conductive rubber cushion ring that is rounded with an arc having a radius slightly smaller than the thickness of the portion is provided, and the resin insulating layer is covered together with the outer surface of the vacuum vessel from the outside.
[0008]
The conductive rubber cushion rings, conical shape and without which the end portion outer peripheral surface of the side covering the metallic steel vacuum container part periphery thickness of the projecting end is substantially 0, the joint step portion of the inner peripheral surface The chamfering is larger than the size of the wax fillet formed in the above.
[0009]
The conductive rubber cushion rings, the ends of the side covering the metallic steel vacuum container part periphery forms a plane perpendicular to the axial direction of the insulating cylinder, the shoulder portion and the metallic vacuum vessel parts outer circumference of the inner circumferential surface A chamfer larger than the size of the braze fillet formed at the joint is applied to the inner diameter side end corner of the covering side.
[0010]
In addition, a connection conductor for connecting the electrode of the element switch and the outside of the power switch is connected inside the resin insulating layer by a fastening means.
[0011]
The fastening means is a bolt whose head side cross section has an arc shape.
[0012]
Further, a voltage dividing electrode is provided on the outer periphery of the connecting conductor inside the resin insulating layer, and the voltage dividing electrode is positioned by an insulator fixed to the connecting conductor.
[0013]
Further, the connection conductor and one of its electrodes are connected inside the resin insulation layer, and a voltage dividing capacitor having a capacitance larger than the stray capacitance between the poles and the phases with respect to the connection conductor is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, a power switch to which the present invention is applied will be described with reference to the drawings. In the drawings showing the respective embodiments of the present invention, the same or corresponding parts are denoted by the same reference numerals, and duplicate description thereof is omitted.
FIG. 1 is a cross-sectional view of an essential part of a power switch according to a first embodiment of the present invention. The power switch includes a main circuit switch 1, a ground switch 2, a main circuit switch 1, and a ground switch. 2 and the exterior insulator 4 that wraps the vacuum container 3 as a main component.
[0015]
The main circuit opening / closing part 1 is composed of a first movable electrode 11 and a first fixed electrode 12 whose intermediate parts are connected by an insulator, and the ground opening / closing part 2 is a second movable electrode 21 and a second fixed electrode 22. The first movable electrode 11 and the second fixed electrode 22 are connected by a flexible cooperative conductor 18. The vacuum vessel 3 includes a metal vessel body 31 provided with openings 31a and 31b through which the main circuit opening / closing portion 1 and the ground opening / closing portion 2 penetrate in parallel, an insulating cylinder 321 to 323 made of ceramic, Cylindrical sealing members 331 and 332, a cup provided with an opening through which either the first movable electrode 11 or the second movable electrode 22 or the first fixed electrode 12 or the second fixed electrode 22 passes. It comprises a cylindrical sealing member 341-344, a cylindrical arc shield 35, bellows 361 and 362, and electric field relaxation rings 371 and 372. The exterior insulator 4 includes cushion rings 411 to 414 and a resin insulating layer 42.
[0016]
The vacuum vessel 3 has either one of a cylindrical sealing member 331 or 332, an insulating cylinder 321 to 323, or a cup-shaped sealing member 341 to 344 outside the four openings 31a and 31b provided in the container body 31. The cup-shaped sealing member 341 or 342 is stacked by being joined in an airtight manner by brazing one end of the bellows 361 or 362 on the peripheral edge of the opening on the bottom surface of the cup-shaped sealing member 341 or 342, and the peripheral edge of the opening 31a. The electric field relaxation ring 371 is joined to the bottom surface of 343, and the electric field relaxation ring 372 is joined to the peripheral edge of the opening 31b and the bottom surface of the cup-shaped sealing member 344 opposite thereto by brazing. The insulating cylinder 322 has a step at the center of the inner surface, and the arc shield 35 is attached to the step with a uniform gap between the inner peripheral wall surface. The diameters of the insulating cylinders 321 and 322 are larger than that of the insulating cylinder 323. This is because the first movable electrode 11 includes an insulating rod 11a and a rod shield 11b at the center thereof, and an arc shield 35 is attached to the center of the inner surface of the insulating cylinder 322.
[0017]
The main circuit opening / closing part 1 is formed in the center of the inner space formed by the container body 31, the insulating cylinders 321 and 322, the cylindrical sealing member 331, and the cup-shaped sealing members 341 and 343, and the container body 31, the insulating cylinder 323, and the cylinder. The ground opening / closing part 2 is attached to the center of the internal space formed by the cup-shaped sealing member 332 and the cup-shaped sealing members 342 and 344, and both are connected by the linking conductor 18, and the other ends of the first movable electrode 11 and the bellows 361 are connected. The other end of the second movable electrode 21 and the bellows 362, the bottom opening periphery of the first fixed electrode 12 and the cup-shaped sealing member 343, and the bottom opening periphery of the second fixed electrode 22 and the cup-shaped sealing member 344 Are hermetically bonded and sealed by brazing. In order to reduce the residual stress of the joint part due to the difference in thermal expansion coefficient between the ceramic insulating cylinders 321 to 323 and the metal members joined thereto, the material and shape of each metal member are devised. This is the same as in the case of the conventional vacuum switch.
[0018]
Integrally from the outer periphery of the cylindrical sealing member 331 or 332 to the vicinity of the joint between the insulating cylinders 321 to 323, near the joint between the insulating cylinder 321 and the cup-shaped sealing member 341, and between the insulating cylinders 321 to 323 and the cup Cushion rings 411 to 414 are respectively covered in the vicinity of the joint portions of the sealing members 341 to 344, and the bottom end portions of the cup-shaped sealing members 341 and 342 and the circuits of the first fixed electrode 12 and the second fixed electrode 22 are provided. The outer surfaces of the vacuum vessel 3 and the fixed electrodes 12 and 22 and the outer surfaces of the cushion rings 411 to 414 excluding the connection side end are covered with a resin insulating layer 42.
[0019]
The cushion rings 411 to 414 are formed by compressing conductive rubber by a compression molding method or the like, and the inner diameter in the molded state is slightly smaller than the outer dimension of the portion fitted to the vacuum vessel 3. The cross-sectional shape is shown in FIG.
[0020]
FIG. 2A shows the cross-sectional shapes of the cushion rings 411 and 412, the X1 portion covers the ends of the insulating cylinders 321 to 323, and the Y1 portion is the outer peripheral surface end of the cup-shaped sealing members 341 to 344. Suffer. The outer diameter side corner of the portion X1 is rounded with a radius smaller than the thickness of this portion to reduce the electric field in this portion in a state where it is attached to the vacuum vessel 3. The outer diameter side of the Y1 portion is a conical surface, and the wall thickness is almost zero at the end. Further, chamfering is performed at corners adjacent to the X1 portion on the inner diameter side in order to avoid interference between the insulating cylinders 321 to 323 and the braze fillets formed at the joint portions of the cup-shaped sealing members 341 to 344.
[0021]
FIG. 2 (b) shows the cross-sectional shapes of the cushion rings 413 and 414. The X2 portion covers the ends of the insulating cylinders 321 to 323, and the Y2 portion covers the outer peripheral surface of the cylindrical sealing member 331 or 332. Yeah. Further, an end surface in contact with the container body 31 is indicated by Z. The outer diameter side corner of the X2 portion is rounded with a radius smaller than the thickness of this portion to reduce the electric field in this portion when the X2 portion is attached to the vacuum vessel 3. On the inner diameter side of the Y2 portion, the corner portion adjacent to the X2 portion and the corner portion on the end face Z side are joined portions of the insulating cylinders 321 to 323 and the cylindrical sealing member 331 or 332, and the container body portion 31 and the cylindrical sealing member. Chamfering is performed to avoid interference with the braze fillet formed at the joint portion 331 or 332. The Z surface is flat so as to be in close contact with the container body 31.
[0022]
The cushion rings 411 to 414 alleviate electric field concentration at the outer peripheral edge portion of the braze fillet formed at the outer peripheral edge of the metallized layer formed at the ends of the insulating cylinders 321 to 323 of the vacuum vessel 3 or at the joint portion with other members. Let In addition, it prevents the penetration of the resin into the wax fillet portion when the resin insulating layer 43 is formed by a casting method or the like, and relaxes the shrinkage stress of the resin insulating layer 43 and the thermal stress due to the temperature change during operation. It has.
[0023]
The main circuit opening / closing part 1 and the ground opening / closing part 2 are incorporated in the vacuum vessel 3, and the cushion rings 411 to 414 are attached as described above, and these are fixed to a predetermined mold, and an epoxy resin resin insulation layer 42 is cast by a casting method. Form.
[0024]
The power switch configured as described above comprises the main circuit switching unit 1 and the ground switching unit 2 by two element switches provided inside the vacuum vessel 3, and the insulating cylinder of each vacuum vessel 3 and each metal seal A cushion ring is attached to the outer periphery of the joint portion with the component, and the outer surface excluding the vicinity of the terminal portion and the sealing portion of the movable electrode is surrounded by the exterior insulator 4, so that the strength of the joint portion of the vacuum vessel 3 is not reduced. The required insulation distance between the charged parts can be reduced, and functions equivalent to those of the conventional ring main switchgear can be realized in a small occupied volume. In addition, even if a short circuit occurs inside the power switch, this part is vacuum, so there is no pressure rise at the power switch mounting part, and it is easy and economical to configure a power switch with high safety. Great effect.
[0025]
In the above description, the power switch has an element switch for one phase composed of a pair of main circuit switching units and a ground switching unit. However, a power switch integrated with three phases may be used.
[0026]
FIG. 3 is a cross-sectional view of a main part relating to a modification of the power switch shown in FIG. 1 and is different from the power switch shown in FIG. 1 in the following points.
Of the two openings on the main circuit opening / closing part 1 side provided in the container body 3, the opening 31c on the first fixed electrode 12 side is the same as the size of the arc shield 35, and an arc is formed around the opening 31c. One end of the shield 35 is joined by brazing. The insulating cylinder 322 is gradually reduced in diameter in the vicinity of one end thereof and has the same dimensions as the insulating cylinder 323 at the end.
[0027]
Since it comprised as mentioned above, since the cup-shaped sealing member joined to the fixed electrode 12 by the side of the main circuit opening / closing part 1 can be shared with the cup-shaped sealing member joined to the fixed electrode 22 by the side of the ground opening / closing part 2, sealing is performed. The number of types of members can be reduced.
[0028]
Embodiment 2. FIG.
FIG. 4 is a partial cross-sectional view of the fixed electrode lead portion of the composite vacuum switch according to the second embodiment of the present invention.
The first fixed electrode 12 terminates in the resin insulating layer 42 and is connected to the bus-side connection terminal 52 via the connecting conductor 51. Further, the second fixed electrode 22 is also terminated inside the resin insulating layer 42 and connected to the load side connection terminal 54 via the connecting conductor 53. A cylindrical voltage dividing electrode 55 used for voltage detection is disposed concentrically with the load side connection terminal 54 via a support insulator 56 on the outer periphery of the load side connection terminal 54 inside the resin insulating layer 42.
The first fixed electrode 12, the connecting conductor 51, and the bus-side connection terminal 52 are connected, and the second fixed electrode 22, the connecting conductor 53, and the load-side connecting terminal 54 are connected to each other with the head section having an arc-shaped side section. The bolt 60 is used for fastening.
[0029]
Since it is configured as described above, when it is fixed to the mold for forming the resin insulation layer in a state where the vacuum vessel, the main circuit opening / closing part and the ground opening / closing part are integrated, each movable part determined by the allowable stress of each brazing part There is a margin in the relative dimensional error allowed for the positional relationship between the electrode and each fixed electrode. This is because the dimensions can be adjusted by the connecting portion of the fixed electrode 12, the connecting conductor 51, and the bus-side connection terminal 52, and the connecting portion of the fixed electrode 22, the connecting conductor 53, and the load-side connecting terminal 54. For example, an adjustment allowance is appropriately given to each connecting portion, the connecting conductor 51 and the bus-side connection terminal 52 are connected on the assembly jig corresponding to the mold, and the second fixed electrode 22 and the connecting conductor 53 are connected to the load side. The terminals 54 may be connected.
[0030]
With such a configuration, productivity can be improved and manufacturing costs can be reduced. In addition, since the electric field in the vicinity of the conductor connecting portion can be relaxed, the thickness of the resin insulating layer 42 in the portion can be reduced, and the power switch can be downsized.
In addition, since the positioning of the voltage dividing electrode 55 to the mold is determined by the position of the load side connection terminal 54, it is not necessary to position from the mold and workability can be improved. Further, since the voltage dividing electrode 55 can be attached to an arbitrary position of the load side connection terminal 54, it is easy to optimize the potential distribution inside the resin insulating layer 421 and contribute to miniaturization.
[0031]
In the above description, the voltage dividing electrode is provided around the load side connection terminal. However, as shown in FIG. 5, the capacitor 6 is connected from the connecting conductor 53 via the connection line 55 and the capacitor terminal 61 is provided outside the mold. It is good also as a structure.
If the capacitance of the capacitor 6 is made larger than the stray capacitance between the poles or the stray capacitance between the phases, the voltage can be detected even when the bus side or the adjacent phase is being charged.
[0032]
【The invention's effect】
Power switch according to the invention, the resin insulating layer has covered from the outside of the iso near the junction of the vacuum container insulated cylinder and the metallic vacuum vessel parts transfection ring of the conductive rubber together with the vacuum container outer surface, conductive The insulating rubber cushion ring covers the corner of the outer peripheral edge of the insulating cylinder at one end, the outer periphery of the metal vacuum vessel part at the other end, and the end corner on the side covering the corner of the outer peripheral edge of the insulating cylinder. Since it is rounded with an arc having a radius slightly smaller than the thickness, the electric field concentration at the outer diameter side corner portion of the corner of the insulating cylinder end is reduced, and the electric field concentration at the outer peripheral edge portion of the braze fillet formed at the junction is reduced. Relax. Further, it prevents the penetration of the resin into the braze fillet when the resin insulating layer is formed by a casting method or the like, and alleviates the shrinkage stress of the resin insulating layer and the thermal stress due to the temperature change during operation.
[0033]
The conductive rubber cushion rings, conical shape and without which the end portion outer peripheral surface of the side covering the metallic steel vacuum container part periphery thickness of the projecting end is substantially 0, the joint step portion of the inner peripheral surface Since the chamfering larger than the size of the wax fillet formed on the outer peripheral portion of the solder fillet is performed, electric field concentration at the outer peripheral edge portion of the wax fillet formed at the joint is more reliably mitigated.
[0034]
The conductive rubber cushion rings, the ends of the side covering the metallic steel vacuum container part periphery forms a plane perpendicular to the axial direction of the insulating cylinder, the shoulder portion and the metallic vacuum vessel parts outer circumference of the inner circumferential surface Since chamfering larger than the dimension of the braze fillet formed at the joint portion is performed at the inner diameter side end corner portion of the covering side, electric field concentration at the outer peripheral edge portion of the braze fillet formed at the joint portion is more reliably ensured. Relax.
[0035]
In addition, since the connecting conductor that connects the electrode of the element switch and the outside of the power switch is connected by the fastening means inside the resin insulating layer, the productivity is improved and the manufacturing cost can be reduced.
[0036]
In addition, since the fastening means is a bolt having a circular section on the head side, the electric field in the vicinity of the conductor connecting portion is relaxed, the thickness of the resin insulating layer at that portion can be reduced, and the power switch can be downsized.
[0037]
In addition, a voltage dividing electrode is provided on the outer periphery of the connecting conductor inside the resin insulation layer, and this voltage dividing electrode is positioned by an insulator fixed to the connecting conductor, so that it is not necessary to position the voltage dividing electrode with a mold and workability is improved. Out. Furthermore, since the voltage dividing electrode can be attached to any position of the connecting conductor, it is easy to optimize the potential distribution inside the resin insulating layer, and the power switch can be miniaturized.
[0038]
In addition, since the connection conductor and one of its electrodes are connected inside the resin insulation layer, and the capacitance is greater than the stray capacitance between the poles and between the connection conductors, the bus side and adjacent phases are charged. In particular, voltage detection is possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing a first embodiment of a power switch according to the present invention.
FIG. 2 is a cross-sectional view of a cushion ring used in the power switch according to the present invention.
FIG. 3 is a cross-sectional view of a main part showing a modification of the power switch shown in FIG.
FIG. 4 is a cross-sectional view of a main part showing a second embodiment of a power switch according to the present invention.
FIG. 5 is a cross-sectional view of an essential part showing a modification of the power switch shown in FIG. 4;
FIG. 6 is a configuration diagram of a conventional ring main opening / closing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main circuit opening / closing part, 2 ... Grounding opening / closing part, 3 ... Vacuum container 3, 4 ... Exterior insulator 321-323 ... Insulating cylinder, 331 and 332 ... Cylindrical sealing member 341-344 ... Cup-like sealing member, 411-414 Cushion ring 42 Resin insulation layer

Claims (7)

Two element switches that are opened and closed by an operation mechanism attached outside the vacuum container are enclosed inside the vacuum container, and one electrode of each element switch is connected to the inside of the vacuum container by a flexible conductor, and a resin insulating layer In the power switch covering the outer surface of the vacuum vessel by
Cover the corner of the outer periphery of the insulating cylinder at one end and the outer periphery of the metal vacuum vessel component at the other end, and the end corner on the side covering the corner of the outer periphery of the insulating cylinder has a radius slightly smaller than the thickness of this portion. An electric power switch comprising a conductive rubber cushion ring which is rounded with an arc, and is covered with the resin insulating layer together with the outer surface of the vacuum vessel from the outside thereof. The conductive rubber cushion rings before Symbol metal vacuum container part the end portion outer peripheral surfaces of the side covering the outer peripheral thickness of the projecting end becomes substantially 0 conical shape and without the joining to the stepped portion of the inner peripheral surface The power switch according to claim 1, wherein chamfering that is larger than the size of the braze fillet formed in the portion is performed. The conductive rubber cushion rings before Symbol ends of the side covering the metallic vacuum vessel parts periphery forms a plane perpendicular to the axial direction of the insulating cylinder, the stepped portion and the metal vacuum container part of the inner peripheral surface 2. The electric power switch according to claim 1, wherein a chamfer larger than a dimension of a braze fillet formed in the joint portion is provided at a corner portion on an inner diameter side on a side covering the outer periphery.   The electric power according to any one of claims 1 to 3, wherein a connection conductor that connects an electrode of the element switch and the outside of the power switch is connected inside the resin insulating layer by a fastening means. Switch.   5. The electric power switch according to claim 4, wherein the fastening means is a bolt whose head side section is arcuate.   The voltage dividing electrode is provided on the outer periphery of the connecting conductor inside the resin insulating layer, and the voltage dividing electrode is positioned by an insulator fixed to the connecting conductor. The power switch described in 1.   2. A voltage dividing capacitor having a capacitance larger than a stray capacitance between electrodes and a phase with respect to the connection conductor, wherein the connection conductor and one of the electrodes are connected inside the resin insulating layer. The power switch according to claim 5.

Images