JP4458631B2 - Three-phase bus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-phase bus provided in a gas insulated switchgear and the like, and more particularly to a three-phase bus provided with a three-phase conductor in a container filled with an insulating gas.
[0002]
[Prior art]
In recent years, gas insulated switchgears have been developed and widely used due to the difficulty in acquiring land for the construction of substation facilities and the necessity of environmental harmony. This gas insulated switchgear is composed of a charging part in a metal container filled with an insulating medium having high dielectric strength such as SF ₆ gas, and is smaller and safer than a switchgear in which the charging part is exposed to the outside. Can be improved. Such a gas-insulated switchgear is often further reduced in size by configuring it as a three-phase collective type in which three-phase conductors are arranged in the same container.
[0003]
In the container of the three-phase collective gas insulated switchgear, a three-phase bus is usually formed by supporting three conductors by a three-phase insulating spacer. In particular, the main bus has been three-phased recently even in the class of 300 kV or higher. An example of such a three-phase bus that has been conventionally proposed will be described below with reference to FIG.
[0004]
That is, the three-phase bus includes a cylindrical grounding container 1, a three-phase insulating spacer 2 provided in the grounding container 1, and a first-phase conductor 3A and a second phase supported by the three-phase insulating spacer. The conductor 3B and the third-phase conductor 3C are the main constituent elements. The centers of the conductors 3A, 3B, 3C of each phase constitute a right isosceles triangle, and the line connecting the center of the second phase conductor 3B and the center of the grounding container 1 is 90 ° (horizontal) ). The reason why the conductors 3A, 3B, and 3C of each phase are arranged in an isosceles right angle is to secure an insulation distance for leading the conductor 3B from between the conductors 3A and 3C.
[0005]
In general, the arrangement of the conductors of the three-phase bus used in the high voltage apparatus is determined in consideration of the insulation distance between the conductors and the container and the insulation distance between the conductors. In the above prior art, the first-phase, second-phase, and third-phase conductors 3A, 3B, and 3C are arranged so as to maintain a necessary insulation distance. In particular, the distance between the third phase conductor 3C and the inner wall of the grounding container 1 depends on the influence of the staying foreign matter at the bottom of the grounding container 1 by separating it from the peripheral part on the bottom side where the metal powder or the like of the grounding container 1 tends to stay. Prevents deterioration of insulation performance.
[0006]
[Problems to be solved by the invention]
By the way, in the conventional three-phase bus as described above, the vicinity of the three-phase insulating spacer 2 may require a larger distance than the space distance between each conductor 3A, 3B, 3C and the inner wall of the grounding container 1. is there. This is because when a foreign substance floats and adheres to the surface of the three-phase insulating spacer 2 due to electrostatic force, the dielectric breakdown occurs depending on the position. The three-phase insulating spacer can be formed by reducing the diameter of the ground container 1 while ensuring a sufficient creepage distance. There is a limit to the reduction of 2. In order to prevent flying, special considerations such as providing a foreign substance trap in the low electric field part in the vicinity of the three-phase insulating spacer 2 are necessary.
[0007]
Furthermore, in the conventional conductor arrangement, the distance between the first phase conductor 3A and the inner surface ceiling of the ground container 1 is shortened. In this part, gas that has become lighter due to the heat generated by the conductor during energization gathers, raising the container temperature, which is disadvantageous for energizing a large current, and hinders downsizing of the equipment.
[0008]
Conventionally, a three-phase bus with an equilateral triangle with one apex facing the celestial direction is also provided, but in such a three-phase bus, a branch bus is formed in a 90 ° direction (horizontal direction) with respect to the top and bottom. It cannot be derived and can only be applied to buses with no branching. In addition, gas that has become lighter due to heat generated by the conductor during energization gathers between the top bus conductor and the ceiling of the container, raising the container temperature and increasing the current. It is disadvantageous for energization.
[0009]
The present invention has been made in response to such a conventional situation, and it is possible to reduce the size while maintaining reliability by sufficiently securing the insulation distance between the ground container and each phase conductor and the insulation distance between each phase conductor. The purpose is to provide a three-phase bus that can be used.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 comprises a cylindrical container filled with an insulating gas, and a three-phase conductor provided along the axial direction inside the container. The centers of the three-phase conductors are located at the vertices of an isosceles triangle having an apex angle greater than 60 ° and less than 90 °, and the center of the conductor at the position forming the apex angle is the cylindrical shape. The isosceles triangle has a base that is longer than the other two sides and is further divided into three phases that are branched from the container. The branch bus is branched horizontally toward the vertex of the isosceles triangle.
[0011]
In the invention of claim 1 as described above, since the distance between the conductors can be secured when providing the branch path while securing the insulation distance from the bottom surface of the container, the insulation distance between the conductors is also ensured. Can do. And since the conductor is at a position displaced by 30 ° from the position of the lowest surface of the container, a sufficient insulation distance can be ensured between the conductor and the bottom surface of the container, and the bottom surface electric field can be suppressed. Can be prevented. Therefore, the entire three-phase bus can be reduced. In addition, even if a minute foreign object is present at the closest part of the conductor of the container, once the AC voltage is applied and floats, the foreign object moves in the ground direction of the ground container due to the force of gravity and reaches the vicinity of the bottom surface. Since the distance to the conductor is increased, it will no longer behave and will be rendered harmless.
In addition, by matching the direction of the branch path with the apex direction of the isosceles triangle of the first three-phase bus, compared to the case where it does not match, the branch path of the first three-phase bus is 180 ° on the opposite side, A wider space can be provided, and other devices can be incorporated.
[0014]
The invention of claim 2 is configured such that the cross section of the conductor of the three-phase branch bus leading portion has a flat shape, and the minor axis sides of the flat cross section face each other. That is, in the three-phase bus of claim 2, the conductor and the branch conductor have a flat cross section only at a portion where the conductor of the first three-phase bus intersects the branch conductor of the branch path, and the minor diameter of the flat cross section It is characterized in that the sides are arranged facing each other.
[0015]
In the invention of claim 2 as described above, the conductor can be led to the branch portion without changing the size of the container in order to maintain the necessary insulation distance at the conductor crossing portion even when the branch path is provided. .
[0016]
The invention of claim 3 is configured such that the three-phase buses are arranged symmetrically in a U-shape or H-shape with the branch bus as an intermediate portion. That is, in the three-phase bus according to claim 2, the first structure is derived in the same direction as the first three-phase bus in a direction 180 ° opposite to the direction in which the first branch path of the first three-phase bus is derived. The direction of an isosceles triangle having two branch paths and the second three-phase buses having a mirror image relationship with the first three-phase buses, each of which is composed of the conductors of the branch paths at a midpoint of the branch path And the first branch path and the second branch path are connected to each other.
In the invention of claim 3 as described above, the conductor arrangement according to the present invention can be configured even in a highly reliable multiple bus system.
[0017]
According to a fourth aspect of the present invention, an opening / closing mechanism is provided on the opposite side of the branch bus. That is, in the first three-phase bus of claim 3 , a third branch path is disposed at a position opposite to the first branch path by 180 °, and an opening / closing mechanism is provided in the third branch path. The opening / closing mechanism includes a movable contact, an insulating operation rod, and the like.
In the invention of claim 4 as described above, the disconnector can be disposed by effectively utilizing the space vacated by the conductor arrangement of the present invention.
[0018]
According to the invention of claim 5, an insulating spacer is provided at the end of a cylindrical container, and the apex of a vertical isosceles triangle having an apex angle greater than 60 ° and less than 90 ° and a horizontal base on the insulating spacer. The embedded conductor is provided at the position, and the three-phase conductor and the embedded conductor are connected to each other in the closest phase without changing the phase order. That is, in the three-phase bus of claim 1, an insulating spacer is provided at the container end, and three embedded conductors are arranged in this insulating spacer so that the apex of the isosceles triangle is positioned in the celestial direction with respect to the celestial direction. The three-phase conductor and the buried conductor are connected to each other in the closest phase without changing the phase order.
In the invention of claim 5 as described above, the embedded conductor of the insulating spacer which is easily affected by the decrease in insulation due to the foreign matter can be separated from the ground direction, and the reliability is further improved.
[0019]
The invention of claim 6 has a configuration in which a conductor is led out for each phase and a single-phase branch bus is provided on an extension line outside the line connecting the center of the conductor of each phase and the center of the container.
In the invention according to the sixth aspect as described above, since the distance between the respective phase branches can be divided into almost equal parts, the branch pipe diameter can be maximized as compared with other conductor arrangements.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
The three-phase bus according to the first embodiment of the present invention will be described with reference to FIGS. That is, as shown in FIG. 1, the first three-phase bus 6 and the second three-phase bus having the same structure as the first three-phase bus 6 and having a mirror image relationship with respect to the cross-section of the branch conductor. 7 in such a manner that the three-phase branch bus 8 is shared.
[0023]
The first three-phase bus 6, the second three-phase bus 7 and the three-phase branch bus 8 are respectively connected to the first-phase bus conductor 3 a, the second-phase bus conductor 3 b and the third phase in the cylindrical grounding container 1. A phase busbar conductor 3c is provided. The centers of the bus conductors 3a, 3b, 3c of each phase form an equilateral triangle, and the line connecting the center of the bus conductor 3b and the center of the grounding container 1 is 90 ° (horizontal direction) with respect to the top and bottom direction. Are arranged as follows.
[0024]
The three-phase insulating spacer 2 includes a spherical base portion 2a having a peripheral portion fixed so as to cover a cross section inside the grounded container 1. Three cone portions 2b projecting in one direction parallel to the axis of the ground container 1 are formed on the raised surface side of the base portion 2a. All of these cone portions 2b have the same shape, and are embedded with a first-phase embedded conductor 4a, a second-phase embedded conductor 4b, and a third-phase embedded conductor 4c, respectively. A first-phase branch conductor 5a, a second-phase branch conductor 5b, and a third-phase branch conductor 5c are led out from the middle of the embedded conductors 4a, 4b, and 4c of each phase.
[0025]
Further, the distance between the third-phase buried conductor 4c and the first-phase and second-phase buried conductors 4a and 4b is the same as that between the first-phase and second-phase buried conductors 4a and 4b and the ground container 1. It is a distance having a dielectric strength 1.5 times the dielectric strength between the two. Branch conductors 5a, 5b, and 5c are led out from the bus conductors 3a, 3b, and 3c arranged in an equilateral triangle, respectively. Each of the conductors is hollow, and a movable contact 10 that is configured to be slidable therein is provided. It arrange | positions and it is comprised so that it can operate with the insulating rod 9 in the opposite direction 180 degree | times from the previous branch conductor derivation | leading-out direction.
[0026]
One of the three-phase insulating spacers 2 on both sides of the busbar is configured so that the embedded conductors 4a, 4b, 4c are arranged in an upper regular triangle, and each of the bus conductors 3a, 3b, 3c arranged in a horizontal regular triangle is 30 °. Connected in the direction of rotation.
[0027]
In addition, the cross-sectional shape of the conductor is partially elliptical at the intersection of the bus conductors 3a, 3b, 3c and the branch conductors 5a, 5b, 5c, and the short sides of the ellipse are opposed to each other.
[0028]
The operation and effect of the three-phase bus of the present embodiment having the above configuration is as follows. That is, as shown in FIG. 2 (a), the bus conductors 3a, 3b, 3c and the buried conductors 4a, 4b, 4c (hereinafter, only the buried conductor will be described) are formed on the base portion of the three-phase insulating spacer 2. It is arranged on a circle with a radius r centered on the center O of 2a, and is arranged so that the center of the conductor forms an equilateral triangle. Further, these embedded conductors 4 a, 4 b, 4 c are arranged at a distance A from the inner wall of the ground container 1.
[0029]
The third-phase embedded conductor 4c is located on the bottom side of the ground container 1, but is offset from the bottom surface by a distance X by an amount that is inclined from the lowest surface. Therefore, the distance Y between the third-phase buried conductor 4c and the bottom surface of the ground container 1 always satisfies the relationship Y> A as shown in FIG. Here, the distance Y is a distance at which the metal foreign object does not rise when the commercial frequency voltage is applied even if a metal foreign object having a length of 3 mm or less exists. Therefore, since the embedded conductor 4c does not come in the vertical direction, a sufficient insulation distance can be provided between the buried conductor 4c and the lowest part of the ground container 1. Therefore, it is possible to reduce the size while maintaining high insulation performance.
[0030]
Even if there is a foreign object between the embedded conductor 4c and the grounding container 1, the foreign object levitated by the application of an alternating voltage to the embedded conductor 4c is caused by gravity as shown in FIG. 2 (b). Due to the influence, it moves to the bottom surface of the grounded container 1 which is the lowest electric field portion, and finally becomes harmless.
[0031]
Furthermore, since the conductors are arranged in an equilateral triangle in the present embodiment, the space between the third phase embedded conductor 4c and the other embedded conductors 4a and 4b is more efficient than the structure in which only the lowest part is separated from the bottom surface. Can be a distance having a dielectric strength 1.5 times the dielectric strength between the other buried conductors 4a and 4b and the wall of the ground container 1, and therefore the buried conductors 4a and 4b of each phase. , 4c can be sufficiently secured. Therefore, it is possible to reduce the size of the device while maintaining high insulation performance.
[0032]
Further, since the insulation distance between the embedded conductor 4c and the ground container 1 is a distance at which the metal foreign object does not reach the conductor when the commercial frequency voltage is applied, the insulation performance is affected by the metal foreign object present at the bottom of the ground container 1. Will not drop. In this configuration, the foreign matter once dropped on the lowest surface does not rise again due to its trapping effect, so there is no need to provide an extra trap device in the vicinity of the three-phase insulating spacer 2.
[0033]
Furthermore, by arranging the conductors in a horizontal regular triangle arrangement, it becomes possible to arrange a switch such as a disconnect switch by a horizontal operation. Thereby, the influence difference by the gravity of the movable part in turning-on operation and turning-off operation is eliminated, and the switch can be operated with substantially the same energy. Therefore, it is not necessary to absorb excess energy with a damper or the like as in the case of the influence of gravity, and the size of the operating device can be reduced, thereby saving energy.
[0034]
In the above description, the case of a horizontal equilateral triangle has been described. However, a horizontal isosceles triangle is used so that the distance between the center of the conductor at 90 ° with respect to the top and bottom direction and the center of the other two-phase conductors are equal. The conductor may be arranged such that the length of the side other than the isosceles side is the longest and the apex angle is 60 ° to less than 90 °.
[0035]
In addition, the insulation separation distance can be obtained by making the portions where the conductors intersect each other have a cross-sectional shape such as an ellipse, a flat shape, or an ellipse and make the short sides face each other. In this way, it is possible to prevent the entire apparatus from becoming large by making only a part of the intersections into an elliptical shape or the like.
[0036]
FIG. 3 shows a three-phase bus according to the second embodiment of the present invention. The three-phase buses are provided with bus conductors 3a, 3b, 3c arranged in a horizontal regular triangle, and single-phase branch buses 11a, 11b, 11c are derived for each phase. 11a, 11b, and 11c have built-in instrument transformers 12 for each phase. A three-phase current transformer 13 is built in the three-phase bus.
[0037]
In the second embodiment, the transformer 12 for an instrument and the three-phase current transformer 13 can be accommodated with a minimum bus diameter by taking advantage of the feature that the conductors are arranged in a horizontal regular triangle. In addition, it is possible to provide a highly reliable system in terms of insulation.
[0038]
【The invention's effect】
As described above, the three-phase bus of the present invention has a configuration in which conductors are arranged in a horizontal isosceles triangle having an apex angle of more than 60 ° and less than 90 ° in a grounded container. A sufficient insulation distance can be secured between them, no extra foreign matter trap is required, and reduction in size can be achieved while maintaining reliability.
[Brief description of the drawings]
FIG. 1 shows a three-phase bus according to a first embodiment of the present invention, wherein (a) is a plan view showing the inside of a grounded container, and (b) is an elevation view taken along line Ib-Ib of (a). (C) is the Ic arrow directional view of (a), (d) is sectional drawing which follows the Id-Id line of (a).
FIG. 2 is a diagram showing an operation of a three-phase bus according to the first embodiment of the present invention.
FIGS. 3A and 3B show a three-phase bus according to a second embodiment of the present invention, FIG. 3A is a plan view showing the inside of a grounded container, FIG. 3B is a view taken along the arrow IIIb-IIIb in FIG. ) Is a sectional view taken along line IIIC-IIIC in (a).
FIG. 4 shows a conventional three-phase bus, (a) is an elevation view showing the inside of the grounded container, and (b) is a sectional view taken along line IVb-IVb in (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Grounding container, 2 ... Three-phase insulating spacer, 2a ... Base part, 2b ... Cone part, 3A, 3B, 3C ... Conductor of each phase, 3a, 3b, 3c ... Bus conductor, 4a, 4b, 4c ... Embedded Conductor, 5a, 5b, 5c ... branch conductor, 6 ... first three-phase bus, 7 ... second three-phase bus, 8 ... three-phase branch bus, 9 ... insulating rod, 10 ... movable contact, 11a, 11b , 11c: Single-phase branch bus, 12: Instrument transformer, 13: Three-phase current transformer.

Claims (6)

A cylindrical container filled with an insulating gas, and a three-phase conductor provided along the axial direction inside the container,
Each center of the three-phase conductor is located at each vertex of an isosceles triangle having an apex angle greater than 60 ° and less than 90 °, and the center of the conductor at the position forming the apex angle is the cylindrical shape. While the line formed when connecting with the center of the container is arranged in the horizontal direction, the base of the isosceles triangle is longer than the other two sides, and further, the three-phase branching from the container A three-phase bus, wherein the branch bus is horizontally branched to the apex side of the isosceles triangle. Conductor cross-section of the three-phase branch bus deriving unit is a flat shape, the three-phase bus of claim 1, wherein the minor axis between the flat cross section, characterized in that the faces. 2. The three-phase bus according to claim 1 , wherein the three-phase bus is arranged in a U-shape or an H-shape with the branch bus as an intermediate portion. The three-phase bus according to claim 3 , wherein an opening / closing mechanism is provided on the opposite side of the branch bus. An insulating spacer is provided at the end of the cylindrical container, and is embedded at each vertex of a vertical isosceles triangle having an apex angle greater than 60 ° and less than 90 ° and a horizontal base on the insulating spacer. 2. The three-phase bus according to claim 1, wherein a conductor is provided, and the three-phase conductor and the buried conductor are connected to each other in the closest phase without changing the phase order.   2. The three-phase bus according to claim 1, wherein a conductor is led out for each phase and a single-phase branch bus is provided on an extension line extending outward from a line connecting the center of the conductor of each phase and the center of the container.

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