JP2001145240A - Gas-insulated bus bar and gas-insulated switchgear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-insulated bus bar and a gas-insulated switchgear that make it possible to reduce electromagnetic force produced at bends in a current-carrying conductor due to the current passed through the current- carrying conductor and its induction field. SOLUTION: The inside or inside inner wall face of a conductive tank at a bend in a gas-insulated bus bar is made of magnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated switchgear, and more particularly, to a gas-insulated switchgear in which electromagnetic force generated in a current-carrying conductor of a gas-insulated bus is reduced and a gas-insulated switchgear using the same.

[0002]

2. Description of the Related Art In recent years, due to an increase in power demand and a demand for miniaturization of power equipment, SFs having high insulation performance have been used in the backbone of power transmission systems.
There is a tendency to frequently use gas-insulated equipment in which conductive conductors and electric devices are housed in a conductive tank filled with six gases. A basic component of the gas-insulated switchgear is a gas-insulated bus. In the gas-insulated bus, a current-carrying conductor is supported via an insulating spacer in a conductive tank filled with SF6 gas.

When an electric current is applied to a current-carrying conductor of a gas-insulated bus, an eddy current is generated in the conductive tank. At this time, the current-carrying conductor receives an electromagnetic force due to a current flowing through the current-carrying conductor of the other phase.

At the same time, electromagnetic force is also received from eddy currents generated in the tank. In particular, in a gas-insulated bus in which three conductive conductors are accommodated in one conductive tank called a three-phase batch type, since three conductive conductors are arranged close to each other, a large electromagnetic force is present between the conductive conductors. Force is generated. In addition, in the case of a phase-separated type gas-insulated bus in which the current-carrying conductors are arranged one by one in a conductive tank, the distance between the current-carrying conductors is wider than in the three-phase batch type. Although the electromagnetic force is small, a large electromagnetic force is received by the self-current of the current-carrying conductor in the direction changing portion called the bent portion.

[0005] In particular, with the recent increase in power transmission capacity, the electromagnetic force received by the current-carrying conductor tends to increase. Further, with regard to the three-phase package type gas-insulated bus, the spacing between the current-carrying conductors tends to be reduced with the miniaturization of the equipment, and the electromagnetic force received by the current-carrying conductors tends to increase more and more. As a result, the current-carrying conductor and the insulating spacer supporting the current-carrying conductor may be damaged or deformed.

For this reason, the conventional gas-insulated bus generates a demagnetizing field by generating a large eddy current in the conductive tank with respect to the magnetic field generated by the current flowing through the current-carrying conductor. Has been used. However, this method generates a large eddy current in the conductive tank, which causes heat loss due to the eddy current.Therefore, the tank diameter is reduced, or a material having a large resistance such as stainless steel is used for the tank. When the power transmission capacity becomes large, there is a problem that the temperature of the tank rises remarkably.

As a first prior art for addressing this problem, Japanese Patent Laid-Open Publication No. Sho 57-121708 discloses a method in which an outer conductor and an inner conductor are arranged so that their central axes coincide with each other, and the inner conductor and the inner conductor are oriented in the opposite direction. A technique is described in which a current is applied to the outer conductor to generate an electromagnetic force in the direction of the central axis, thereby preventing damage to the support structure of the inner conductor.

[0008] A second prior art is disclosed in Japanese Patent Application Laid-Open No. 57-1136.
Japanese Patent Application Laid-Open No. 21-213421 discloses a technique for increasing the strength of current-carrying conductor support by arranging a conductor-supporting insulator in a direction in which the electromagnetic force received by the current-carrying conductor is largest in a three-phase batch-type gas-insulated bus.

[0009]

However, the above prior art has the following problems. In the first prior art,
It is necessary to pass currents of opposite phase to the inner conductor and the outer conductor at the same time.However, in order to apply a three-phase AC current to gas-insulated buses generally used for power transmission substation equipment, opposite phases are applied to the outer conductor and the inner conductor. It is usually difficult to pass a current. Further, in the second prior art, the strength of the insulating support for supporting the current-carrying conductor can be increased for the straight portion, but the direction of the electromagnetic force applied to the current-carrying conductor changes at the bent portion. It is difficult to increase the strength by the prior art method of arranging insulating supports. Further, in the current-carrying conductor at the bent portion of the gas-insulated bus, an electromagnetic force is generated by a self-current flowing through the current-carrying conductor, but it is difficult to reduce the electromagnetic force in both the first and second prior arts.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the electromagnetic force generated in a current-carrying conductor at a bent portion of a gas-insulated bus so as to improve the strength of the current-carrying conductor, and at the same time to provide an insulating support such as a spacer for supporting the current-carrying conductor. It is an object of the present invention to provide a gas-insulated bus and a gas-insulated switchgear that can cope with an increase in electromagnetic force due to large-capacity power transmission without increasing the strength and number of structures.

[0011]

According to the present invention, there is provided a gas-insulated switchgear comprising a conductive tank and a gas-insulated bus having a current-carrying conductor housed in the conductive tank. In the bent portion of the gas-insulated bus, in the hook-shaped conductive tank, inside the bent portion of the tank, or in the curved corner portion, a portion having a small curvature is formed of iron or silicon steel plate. . Alternatively, a thin non-magnetic material such as an iron or silicon steel plate is attached to a portion having a small curvature on the inner surface of a conductive tank made of stainless steel or aluminum at the bent portion of the gas-insulated bus.

When a current flows through the current-carrying conductor to generate a magnetic field, the magnetic material is magnetized to generate an attractive force in the direction of the magnetic material in the current-carrying conductor. The force can be reduced, and the influence of the electromagnetic force exerted on the conducting conductor by the eddy current generated in the conductive tank can be reduced. Further, since there is no need to newly provide a structure between the conductive tank and the current-carrying conductor, there is no adverse effect that causes dielectric breakdown.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a gas-insulated bus according to the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of a gas-insulated bus of the first embodiment, FIG. 2 is a cross-sectional view of the gas-insulated bus of the first embodiment, and FIG.
FIG. Gas-insulated buses are used for power transmission at substations and switchyards.

FIG. 4 is a side view of the gas insulated switchgear, and FIG.
4 shows the front view of FIG. As shown in FIGS. 4 and 5, the gas insulated switchgear includes devices such as a phase-separated gas insulated bus 20 or a three-phase collective gas insulated bus 20a, a circuit breaker 6, a disconnector 7, and the like. One to three current-carrying conductors are arranged in the conductive tank of the bus bar, and are filled with SF6 gas or the like having excellent insulation performance. Gas-insulated switchgears are used to open and close power systems at substations and switchyards. The circuit breaker 6 is used for immediately disconnecting a fault location such as a ground fault occurring in the power system from the system and preventing damage or destruction of equipment.

The gas insulated switchgear is connected to external power transmission and transformation equipment via a bushing 8 and a cable 9.

As shown in FIGS. 4 and 5, basic components of the gas insulated switchgear include gas insulated buses 20 and 20a, and the components of the gas insulated switchgear are connected by the gas insulated bus. . As shown in FIG. 2, the gas-insulated bus is
The conductive tank 1, the conductive conductor 2, the insulating spacers 4 and 5, and the insulating gas SF 6 sealed in the conductive tank 1.
It is composed of gas (not shown) and the like. Conductive tank 1
Is made of aluminum or stainless steel.
As shown in the cross-sectional view of FIG. 2, the insulating spacer 4 is formed of a dielectric material such as epoxy resin and has a conical or circular shape. In addition, there is an insulating spacer 5 having a columnar shape. The current-carrying conductor 2 is mainly formed of an aluminum material or the like, is supported by an insulating spacer 4, and is hermetically housed in the conductive tank 1 together with SF6 gas, which is a noncombustible gas (insulating gas) of about 3 to 5 atm.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 2 is a schematic sectional view of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. 2 showing the principle of the present invention. This embodiment is an example in which the present invention is applied to a phase-separated gas-insulated busbar, and has a structure in which one conductive conductor 2 is housed in a conductive tank 1.

When an energizing current (alternating current) is applied to the energizing conductor 2 in the direction of arrow 10 (right direction), a magnetic flux is generated inside and outside the conductive tank 1 made of a non-magnetic material in the direction of arrow 11. I do. In the linear portion of the gas-insulated bus, the magnetic flux 11 is orthogonal to the current 10, so that the current-carrying conductor does not receive any electromagnetic force. However, at the bent portion of the gas-insulated bus, the current-carrying conductor 2 receives an electromagnetic force in the direction of the arrow 12 due to the influence of the magnetic flux 11 as shown in FIG. In particular, when the current 10 is large, the strength of the insulating spacer may be insufficient due to the electromagnetic force 12 received by the conductor 2. At this time, the magnetic body wall 3 installed inside the bent portion according to the present invention is magnetized by the magnetic flux 11 generated by the current 10.
When the magnetic wall 3 is magnetized, the current-carrying conductor 2 receives an attractive force 13 in the direction of the magnetic wall 3. Since the direction of the electromagnetic force 12 due to the magnetic flux 11 and the direction of the attraction force 13 due to the magnetic body wall 3 are opposite, as a result, the force received by the current-carrying conductor 2 can be reduced. Therefore, it is possible to cope with an increase in power transmission capacity without increasing the strength of the insulating spacer 5 or the current-carrying conductor 2.

Next, a second embodiment of the gas-insulated bus of the present invention will be described with reference to FIGS. FIG. 6 is a schematic perspective view of the second embodiment, and FIG. 7 is a schematic sectional view of FIG. The figure numbers in parentheses in FIG. 7 indicate the parts hidden behind. The present embodiment is an example in which the present invention is applied to a three-phase collective gas insulated bus.
The configuration is the same as that of the first embodiment except that three conductive conductors 2a, 2b, and 2c are housed in a pair in the conductive tank 1a.

That is, also in this embodiment, in the bent portion of the gas-insulated bus, the conductive tank 3a in the inner portion is made of a magnetic material.

Therefore, also in this embodiment, the electromagnetic force applied to the current-carrying conductor can be reduced as in the first embodiment.
Generally, when the conductive tank 1a is entirely made of a non-magnetic material such as stainless steel or aluminum material in the straight portion of the three-phase gas-insulated bus, if the conductive tanks 2a, 2b , 2c is known to be reduced. However, in the bent portion of the gas-insulated bus, the electromagnetic force caused by the current flowing through the current-carrying conductors 2a and 2c having a small radius of curvature cannot be reduced. By forming the conductive tank 3a inside the bent portion of the present invention from a magnetic material, the electromagnetic force of the current-carrying conductors 2a, 2b, 2c due to its own current can be reduced.

Next, a third embodiment of the present invention will be described with reference to FIG.
An embodiment will be described with reference to FIG. FIGS. 8 and 9 respectively show the first and second embodiments in which the conductive tanks 1 and 1a at the bent portions of the gas-insulated buses are formed of the magnetic bodies 3 and 3a, but in the third and fourth embodiments, As shown in FIGS. 8 and 9, the conductive tanks 1 and 1a including the bent portion are made of a non-magnetic material, and a thin plate 3b made of a magnetic material is attached to the inner surface of the tank inside the bent portion of the conductive tank. According to the present embodiment, it is possible to manufacture at a lower cost than in the first embodiment and the second embodiment, and the effect of reducing the electromagnetic force of the current-carrying conductor in the bent portion remains unchanged. Further, in each of the embodiments, since no new structure is provided between the current-carrying conductor and the conductive tank, the present invention does not cause dielectric breakdown or the like.

As described above, according to each embodiment,
By suppressing the electromagnetic force of the current-carrying conductors at the bends of gas-insulated switchgear such as gas-insulated busbars, it is possible to reduce the size and capacity of conductive tanks and other equipment without increasing the strength of insulating spacers and conductors. Becomes

[0024]

According to the present invention, it is possible to reduce the electromagnetic force generated in the bent portion of the current-carrying conductor due to the magnetization attraction generated by the magnetic wall of the conductive tank due to the magnetic field from the current.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a gas-insulated bus of the present invention.

FIG. 2 is a schematic sectional view of FIG.

FIG. 3 is an enlarged view of FIG. 2 for explaining the operation of the first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a gas insulated switchgear for explaining the operation of the first embodiment of the present invention.

FIG. 5 is a schematic top view of FIG. 4;

FIG. 6 is a schematic configuration diagram of a second embodiment of the gas-insulated bus of the present invention.

FIG. 7 is a schematic sectional view of FIG. 6;

FIG. 8 is a schematic sectional view of a third embodiment of the gas-insulated bus of the present invention.

FIG. 9 is a schematic sectional view of a fourth embodiment of the gas-insulated bus of the present invention.

[Explanation of symbols]

1.1a: conductive tank, 2.2b: conductive conductor, 3.3
a · 3b: conductive tank bent partial magnetic body according to the present invention; 4: insulating spacer (plate), 5.5a · 5b · 5c
... Insulating spacer (column), 6 ... Circuit breaker, 7 ... Switch, 8
... Bushing, 9 ... Cable, 10 ... Arrow indicating the direction of energizing current, 11 ... Arrow indicating magnetic flux by energizing current, 12
... Arrows indicating the direction of the electromagnetic force applied to the current-carrying conductor by the current, 13... Arrows indicating the direction of the force applied to the current-carrying conductor from the magnetic material according to the present invention, 20...
0a: Three-phase collective gas-insulated bus.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiaki Rokunohe 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Kokubu Works, Ltd. (reference) 5G017 AA01 BB20 HH06 5G365 DA14 DB01 DD04 DD06

Claims (3)

[Claims] 1. A gas-insulated bus bar having a conductive tank containing an insulating gas and a current-carrying conductor therein, wherein the inside of the conductive tank at the bent portion is made of a magnetic material and the outside is made of a non-magnetic material. A gas-insulated bus bar. 2. A non-magnetic material is attached to a part of the inner surface of a conductive tank at a bent portion of the non-magnetic conductive tank in a gas-insulated bus having a conductive tank containing an insulating gas and a conductive conductor therein. A gas-insulated bus bar. 3. A gas-insulated bus for transmitting power to an electric power system, a circuit breaker for disconnecting a ground fault point or a short-circuit point generated in the electric power system, and a circuit to be used for connection change and inspection / repair. A gas insulated switchgear comprising a disconnector for disconnecting from a power supply, wherein the gas insulated switchgear according to any one of claims 1 to 2 is provided as the gas insulated bus.