JP2003016886A - Large-capacity vacuum circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-voltage and large-capacity vacuum circuit breaker, having a simple structure and low drive energy by slowing a large current interruption under a high voltage condition, in a vacuum circuit breaker having a single-valve structure. SOLUTION: A fixed electrode 4, fixed to and supported by two or more ribs 2b of a fixed electrode support member 2, is held at the center part within a vacuum valve comprising ceramic or glass insulating cylinders 1a and 1b, metal end plates 8a and 8b, bellows 7a and 7b, and the like. Movable electrodes 5a and 5b are provided above and under (or on both sides) of the fixed electrode 4 and are fixed to movable current-carrying shafts 6a and 6b, respectively. Furthermore, one movable current-carrying shaft 6b is connected directly to a drive unit 10, and the other movable current-carrying shaft 6b is connected to the movable current-carrying shaft 6a via a 1:1 lever 9.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is from 36 kV to 36 kV.
The present invention relates to a high-capacity vacuum circuit breaker used for a high-voltage power distribution system up to kV and a high-voltage power transmission system for 72 kV or more.

[0002]

2. Description of the Related Art Vacuum circuit breakers are widely used at 72 kV or less because they are lightweight and compact, require a small space, are easy to maintain and inspect, and are highly reliable and safe.

The basic structure of a typical vacuum circuit breaker is shown in FIG. The vacuum circuit breaker I shown in the figure corresponds to an arc extinguishing chamber of another conventional circuit breaker such as a gas circuit breaker or an air circuit breaker. As can be seen from the figure, the structure is extremely simple, and the fixed electrode 4 fixed to the upper end plate 3a is placed in the sealed vacuum valve.
Further, a movable electrode 5 which can move up and down is provided, and the movable electrode 5 is fixed to the bellows 7. The movable electrode 5 is a movable energizing shaft 6
Is attached to the tip of the movable energizing shaft 6, and the other end of the movable energizing shaft 6 is connected to the driving device 1.
It is connected to an insulated operating rod (not shown) inside the zero. The lower end plate 3b and the driving device 1 which constitute the vacuum valve
The case units of No. 0 are connected by the insulating support 13.

In such a structure, the drive shaft 6 is connected to the drive unit 1.
When it is moved up and down by 0, the fixed electrode 4 and the movable electrode 5 are brought into contact with each other and separated from each other (opening / closing), so that energization and interruption are performed.

As is well known, the withstand voltage performance in a vacuum state is extremely high, and the opening stroke of such a vacuum circuit breaker is much smaller than that of other circuit breakers. Therefore, a small electromagnetic operating mechanism or a spring operating mechanism is used as the driving device 10.

[0006]

The conventional vacuum circuit breaker described above has the advantages of high reliability, frequent switching characteristics, safety and the like, and further modernization of the high voltage system such as easy maintenance and inspection. Meet the request of the current, currently 3.6kV ~ 36k
It has established a solid position in the area of medium voltage circuit breakers up to V.

In recent years, as the demand for electric power has increased and the capacity of electric equipment has increased, there has been a need for circuit breakers of higher voltage and larger capacity. Increasing the capacity of the vacuum circuit breaker to a high voltage is achieved by increasing the diameter of the vacuum valve and the diameter of the electrodes and increasing the distance between the electrodes during the opening operation.

However, in order to achieve a high voltage in the vacuum circuit breaker, it is not a good idea to increase the opening stroke. This is because the relationship between the gap length between electrodes and the breakdown voltage in a vacuum is not linear as shown in FIG. 8 and the tendency of saturation is remarkable. This is because a distance is required and a large opening stroke is required. Further, since it is necessary to increase the opening speed with the increase of the opening stroke, not only the vacuum valve becomes large, but also the driving device becomes large, which is a disadvantage.

Therefore, it is generally considered to be advantageous to connect two breaking portions I of the conventional vacuum circuit breaker described above in series. However, in such a case, the structure of the vacuum circuit breaker becomes complicated, and the cost increases.

The present invention is intended to solve the problems of the conventional vacuum circuit breaker, and it is to provide a vacuum circuit breaker having a one-valve structure capable of meeting the demand for a large capacity. .

[0011]

In order to solve the above problems, according to the present invention, in a large-capacity vacuum circuit breaker having a fixed electrode and a movable electrode in a vacuum valve, the inside and the outside of the vacuum valve are provided in the central part of the vacuum valve. A fixed electrode is provided that is held by a plurality of ribs that are connected to a disc that communicates with the fixed electrode. The fixed electrode is disposed so as to face the fixed electrode, and one end of each of the two movable energizing shafts whose other end projects outside the vacuum valve. A movable electrode to be held is provided, and one of the movable energizing shafts is directly connected to the driving device and the other of the movable energizing shafts is connected to the one of the movable energizing shafts via a link mechanism, and the two movable electrodes are in opposite directions. Made it possible to move in conjunction.

Further, the second problem solving means is configured such that the fixed electrode sandwiches the conductor portion between the contact portions having a plurality of slits. With such a configuration, a strong longitudinal magnetic field component is generated in the axial direction by the current flowing between the main electrodes where the arc of the fixed electrode is ignited. Thereby, local concentration of the arc can be prevented, a stable arc can be obtained, and the breaking performance can be remarkably improved.

A third means for solving the problems is constituted by connecting the fixed electrode at the center of the vacuum valve and the ribs around the fixed electrode by melting the metal by welding or brazing. With such a configuration, the fixed electrode can be reliably held in the central portion of the valve, and the purpose of improving the blocking performance can be achieved.

The fourth means for solving the problems is constituted by connecting the fixed electrode at the center of the vacuum valve and the rib by pressure working such as caulking, pressure welding or the like. With this configuration,
It becomes easy to hold the fixed electrode in the center of the valve, and the manufacturing cost of the vacuum circuit breaker can be reduced.

In a fifth solution, some of the ribs are made of metal such as stainless steel and iron having a strength higher than that of copper, and the remaining ribs are made of copper or copper alloy. With such a structure, the strength of the rib portion is increased, and the fixed electrode can be held more stably in the center of the vacuum valve.

A sixth solution means is constructed by joining cooling fins to a disk portion which is connected with ribs and communicates from the inside of the vacuum valve to the outside. With such a configuration, the cooling performance can be improved and the capacity of the vacuum circuit breaker can be increased.

Further, a seventh solution means is constituted by insulatingly supporting the portion of the vacuum circuit breaker and fixing it in a metal container, and filling the metal container with a non-combustible oily material. With such a configuration, the withstand voltage performance can be dramatically improved, and the vacuum circuit breaker can be increased in voltage.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. In the drawings, the same or similar parts are designated by the same or similar reference numerals, and duplicate description is omitted.

FIG. 1 is a sectional view showing a first embodiment of the present invention and a plan view of a fixed electrode, in which a vacuum circuit breaker I is shown.
The vacuum valve is composed of insulating cylinders 1a and 1b made of a ceramic or glass window insulator, metal end plates 3a and 3b, and bellows 7a and 7b. At the center of the vacuum valve, the fixed electrode 4 is connected to and held by the plurality of ribs 2b1 to 2b6 of the fixed electrode supporting member 2, and the rib 2b1 is held.
2b6 are connected to the disk portion 2a to which the insulating cylinders 1a and 1b are fixed, through the inside and the outside of the vacuum valve. Further, in the vacuum circuit breaker I having the vertical configuration shown in FIG.
Movable electrodes 5a and 5b are provided on the upper and lower sides facing each other, the movable electrodes 5a and 5b are fixed to the two movable energizing shafts 6a and 6b, and the movable energizing shafts 6a and 6b are fixed to the bellows 7a and 7b. The movable energizing shaft 6b is passed through the openings provided in the central portions of the plates 3a and 3b in a non-contact manner, and the movable energizing shaft 6b is connected to the driving device 1
0, and the other movable energizing shaft 6a is connected to the movable energizing shaft 6b through the link lever 16, the insulating operation rod 9, and the arm portion 18.

Further, as shown in FIG. 1, a plurality of holes 15a1 to 15a4 and 15b1 to 15b4 are concentrically provided on the disk portion 2a communicating from the inside to the outside of the vacuum valve, and the holes 15a1 to 15a4 are provided in the holes 15a1 to 15a4. The plurality of insulating support rods 12a shown in FIG.
A plurality of insulating support rods 12b shown in are fixed. The insulating support rods 12a and 12b are alternately arranged on the concentric circumference, the metal end plate 11a is attached to the upper end of the insulating support rod 12a in FIG. 1, and the metal end plate 11b is attached to the lower end of the insulating support rod 12b. Further, the lower metal end plate 11b is attached to the insulating support member 1
It is fixed to the housing of the driving device 10 via 3. Movable electrode 5
One end of the movable current-carrying shaft 6b fixed to b is connected to the metal end plate 11
The movable energization shaft 6a is connected to the movable part of the drive device 10 so as to be movable through an opening provided in the center part of b.
One end of is movable through an opening provided at the center of the metal end plate 11a, and is connected to the link lever 16 by the arm 18 as described above. The fulcrum 17a of the link lever 16 is rotatably fixed and supported by a fulcrum support member 17 attached to the metal end plate 11a. The position of the fulcrum 17a is adjusted so that the movable electrodes 5a, 5b and the fixed electrode 4 are equidistant from each other when the vacuum circuit breaker I is opened.

In addition to these, in order to prevent the deterioration of the insulation performance of the inner surfaces of the insulating cylinders 1a, 1b due to the adhesion of metal vapor or metal melt scattered from the electrodes, the shields 8a, 8b surrounding the electrodes are provided with ribs 2b1-2b6. Fixed to.

In the above-described first embodiment shown in FIG. 1, when the contact opening operation is performed by the driving force of the driving device 10,
The movable electrodes 5a and 5b are separated from the fixed electrode 4 almost at the same time, and the two contact distances from the fixed electrode 4 are almost the same.

As shown in FIG. 8, in vacuum, when the gap length is small, the dielectric breakdown voltage changes in proportion to the gap length, but when the gap length becomes large, the dielectric breakdown voltage becomes 1/2 of the gap length. It changes in proportion to the square. In FIG. 8, the limit length having a proportional relationship is L1, and the breakdown voltage at this time is V1. The dielectric breakdown voltage when the gap length is 2L1 is V2. In the present embodiment, upon completion of the opening operation of one movable electrode (referred to as opening)
The distance between the electrodes is approximately L1. Therefore, the breakdown voltage due to the opening distance of the two movable electrodes sandwiching the fixed electrode 4 is the sum of the breakdown voltages due to the opening distance of 2V1.
Becomes It is composed of a pair of fixed electrode and movable electrode, and the dielectric breakdown voltage is V2 when the opening distance is 2L1. 2V1
> V2, and it can be seen that in the first embodiment, economically high withstand voltage performance is obtained. Further, as shown in FIG. 8, the gap length L2v1 for obtaining the dielectric breakdown voltage 2V1 with one gap length is the sum of the two gap lengths 2L1.
It can be understood that it is much larger and it is not economical to increase the voltage of the vacuum circuit breaker by one opening distance as compared with the present embodiment.

Therefore, in the first embodiment described above, it is possible to obtain a vacuum circuit breaker having a simple structure and a low driving energy and excellent in breaking performance.

A configuration example of the electrodes of the vacuum circuit breaker according to the second embodiment of the present invention will be described with reference to FIGS. 2 and 3. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.
Here, only different parts will be described.

In this embodiment, the insulating cylinder 1 shown in FIG.
a and 1b, a fixed electrode 4 held by a plurality of ribs 2 in the center is provided with contact portions 4a and 4 provided with slits 4d.
The conductor portion 4c is provided between b. Although not shown, the space between the contact portions 4a and 4b and the contact portion 4
A plurality of spacers made of a high resistance metal material such as stainless steel are fixed between the conductors 4a and 4b and the conductor portion 4c.
4b, between the contactor portion 4a and the conductor portion 4c, and between the contactor portion 4b and the conductor portion 4c are kept at constant distances.
Although the conductor portion 4c is divided into two in FIG. 2, this portion can be divided into multiple divisions such as three divisions and four divisions.

FIG. 3 shows an example of the structure of the movable electrodes 5a and 5b. The movable electrodes 5a and 5b fixed to the movable energizing shafts 6a and 6b connected to the driving device 10 are provided with slits 4e like the contact portions 4a and 4b of the fixed electrode 4.

In the second embodiment, the electrode i ₀ flowing into the contact portion 4b has a conductor portion 4 as shown in FIG.
It is divided into two equal parts by the arm part installed in c, and further flows into the arm part extending to the other contactor part 4a. The shunted currents i ₁ and i _{2 form} a half-circle arc and the contact portion 4
to a. That is, according to FIG. 2D, a coil of one turn is formed around the electrode, and a strong magnetic field (in the axial direction) between the fixed electrode and the two fixed electrodes is generated by the current flowing therethrough. A vertical magnetic field) can be generated. This longitudinal magnetic field acts on the arc generated between the fixed electrode and the two fixed electrodes. Further, the contactor portions 4a, 4
The slit 4d provided in b can minimize the generation of the eddy current in each contact portion and prevent the disappearance of the magnetic field.

When a longitudinal magnetic field is applied, electrons and ions make a circular motion around the magnetic field lines, that is, a cyclotron motion, so that local concentration of the arc can be prevented and loss of charged particles from the electrodes to the outside due to diffusion. Therefore, it is possible to significantly improve the breaking performance.

Therefore, with the fixed electrode structure of the second embodiment, it is possible to obtain a vacuum circuit breaker with a simple structure and a low driving energy which is excellent in breaking performance.

In the fixed electrode according to the third embodiment of the present invention, the fixed electrode 4 shown in FIG. 1 and the ribs 2b1 to 2b6 are joined, and the ribs 2b1 to 2b6 and the disc portion 2a are joined by welding or brazing. It is characterized by performing melting of metal.

With such a joint structure, the fixed electrode can be securely held in the central portion of the valve, and the object of improving the blocking performance can be achieved.

Therefore, with the fixed electrode structure of the third embodiment, it is possible to obtain a vacuum circuit breaker having a simple structure, mechanical stability, and excellent driving performance and low drive energy.

The structure of the fixed electrode according to the fourth embodiment of the present invention is shown in FIG. However, the same parts as those in FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be omitted. Here, only different parts will be described.

The fourth embodiment has a structure in which the plurality of ribs 2 shown in FIG. 1 and the fixed electrode 4 supported thereby are joined by pressure processing such as caulking, pressure welding or the like.

According to the fourth embodiment, the fixed electrode 4 and the rib 2 can be easily coupled, and the structure of the electrode portion for generating the longitudinal magnetic field and improving the blocking performance can be facilitated.

Therefore, in the fourth embodiment, it is possible to obtain a vacuum circuit breaker having a simple structure and a low driving energy which is excellent in breaking performance.

In the vacuum circuit breaker according to the fifth embodiment of the present invention, as shown in FIG.
For supporting the fixed electrode 4 shown in FIG.
Some of b6 are made of a metal such as stainless steel and iron having a strength higher than that of copper, and the remaining ribs are made of copper or a copper alloy having good thermal conductivity.

The fixed electrode 4 shown in FIG. 1 receives an impact force during the closing operation, and if the strength of the ribs 2b1 to 2b6 is not sufficient, the ribs may be deformed and the fixed electrode may not be held in the center of the vacuum valve. In the present embodiment, the strength of the ribs is sufficiently large, so that the fixed electrode can be reliably held at a predetermined position even when a large number of opening / closing operations are performed. In addition, heat dissipation to the outside can be favorably maintained by forming some of the remaining parts from copper or a copper alloy.

Therefore, in the fifth embodiment, it is possible to obtain a vacuum circuit breaker having a simple structure, a long mechanical life, and an excellent breaking performance and a low drive energy.

FIG. 5 shows the structure of the electrodes of the vacuum circuit breaker according to the sixth embodiment of the present invention. However, the same parts as those in FIGS. 1 to 4 are designated by the same reference numerals, and the description thereof will be omitted. Here, only different parts will be described.

In the sixth embodiment, a cooling fin for heat radiation is provided in a disk portion 2a of the fixed electrode supporting member 2 (FIG. 1) which communicates from the inside to the outside of the vacuum valve. That is, the rib 2b1 of the disk portion 2a located on the outer side of the vacuum valve
A plurality of cooling fins 14a at positions close to 2b6
Place ~ 14c. The cooling fins may be arranged on either the front or back surface or the front surface of the disk portion 2a as shown in FIG.

In the sixth embodiment, heat generated in the electrode portion during energization in the closed state and current interruption in the opened state flows from the fixed electrode 4 to the ribs 2b1 to 2b6, and the cooling fin 14 is formed.
The heat is dissipated to the outside of the vacuum valve immediately after being transmitted to a to 14c.

The quality of heat dissipation is one of the important factors that determine the size of the vacuum circuit breaker. The vacuum circuit breaker can be miniaturized by improving the heat dissipation performance by the sixth embodiment. Therefore, according to the present embodiment, it is possible to obtain a vacuum breaker with a small and simple structure and a low driving energy which is excellent in breaking performance.

The structure of the vacuum circuit breaker according to the seventh embodiment of the present invention is shown in FIG. In this embodiment, the breaking portion I of the vacuum circuit breaker shown in FIG. 1 is fixed to the metal container 20 by the insulating support 13.

Further, the conductors 21a and 21b are drawn out from the two movable current-carrying shafts 6a and 6b (FIG. 1) so that they can be energized, insulated from the metal container by the bushings 22a and 22b, and connected to the terminal plates 23a and 23b to connect the electrode portions. And enable the external energization of the metal container.

Further, in the sixth embodiment, the space S in the metal container 20 is filled with a non-combustible or flame-retardant oily material having a low degree of environmental pollution such as silicon oil.

In the conventional vacuum circuit breaker, as compared with the high withstand voltage performance inside the vacuum valve, the dielectric breakdown voltage of the air portion outside the vacuum valve is low, which is a weak point of high voltage and large capacity. In the seventh embodiment, the withstand voltage performance outside the vacuum valve can be dramatically improved by using silicone oil, which has a minimal adverse effect on the environment, and good cooling performance can be secured.

Therefore, according to the seventh embodiment, it is possible to obtain a vacuum circuit breaker having a simple structure, excellent breaking performance, and dramatically higher withstand voltage than the conventional one.

[0050]

As described above, according to the present invention, it is possible to provide a large-capacity vacuum circuit breaker having excellent breaking performance and withstand voltage performance, low driving energy, high reliability, and no adverse effect on the environment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a vacuum circuit breaker and a plan view of a fixed electrode support member showing an embodiment of the present invention.

FIG. 2 is a plan view showing another modification of the fixed electrode portion.

FIG. 3 is a plan view showing another modification of the movable electrode portion.

FIG. 4 is a diagram showing a main part of a movable electrode portion of the present invention.

FIG. 5 is a plan view showing another configuration example of the movable electrode portion.

6 is a schematic side view of the vacuum circuit breaker of FIG. 1 housed in a container.

FIG. 7 is a sectional view of a conventional vacuum circuit breaker.

FIG. 8 is a graph showing the relationship between the gap length and the breakdown voltage in vacuum.

[Explanation of symbols]

1a, 1b: Insulating container cylinder 2: Fixed electrode support member 2a: Disc parts 2b1, 2b2, 2b3, 2b4, 2b5, 2b6: Ribs 3a, 3b: Metal end plate 4: Fixed electrodes 4a, 4b: Contact part 4c: Conductors 4d, 4e: Slits 5a, 5b: Movable electrodes 6a, 6b: Movable energizing shafts 7a, 7b: Bellows 8a, 8b: Shield 9: Insulation operating rod 10: Driving devices 11a, 11b: Insulating end plates 12a, 12b: Insulating rod 13: Insulating support bases 14a, 14b, 14c, 14d, 14e, 14f: Cooling fins 15a1, 15a2, 15a3, 15a4: Insulating rod mounting holes 15b1, 15b2, 15b3, 15b4: Insulating rod mounting hole 16: Link lever 17 : Fulcrum support member 17a: fulcrum 18: arm 20: metal containers 21a, 21b: conductors 22a: 22b: bushings 23a, 23b: terminal board I : Breaking part S of vacuum circuit breaker: Silicon oil filling space

Claims (7)

[Claims] 1. A vacuum circuit breaker having a fixed electrode and a movable electrode in a vacuum valve, wherein a central part of the vacuum valve has:
A fixed electrode is provided that is held by a plurality of ribs that are connected to a disk portion that communicates with the inside and outside of the valve. The fixed electrode is arranged so as to face the front and back surfaces of the fixed electrode, and one end of each protrudes outside the vacuum valve. A movable electrode that is held at the other ends of the two movable energization shafts is provided, and one end of one of the movable energization shafts is directly driven by the drive device, and one end of the other movable energization shaft is connected via a link mechanism connected to the drive device. A large-capacity vacuum circuit breaker characterized in that the movable electrodes are connected to one of the movable energizing shafts so that both movable electrodes can move in interlocking movement in opposite directions. 2. The large-capacity vacuum circuit breaker according to claim 1, wherein the fixed electrode has a structure in which the conductor portion is sandwiched between contact portions having a plurality of slits. Circuit breaker. 3. The large-capacity vacuum circuit breaker according to claim 1 or 2, wherein the fixed electrode at the center and the rib are directly connected to each other. 4. The large-capacity vacuum circuit breaker according to claim 1 or 2, wherein the central fixed electrode and the rib are joined by pressure processing such as caulking, pressure welding, or the like. Circuit breaker. 5. The large-capacity vacuum circuit breaker according to claim 1, wherein some of the ribs are made of stainless steel,
A large-capacity vacuum circuit breaker characterized by being made of a metal such as iron having a strength higher than that of copper, and the remaining ribs being made of copper or a copper alloy. 6. The large-capacity vacuum circuit breaker according to claim 1, wherein cooling fins are joined to the ribs. 7. The large-capacity vacuum circuit breaker according to claim 1, wherein a portion of the vacuum circuit breaker is insulated and supported in a metal container, and the metal container is filled with a nonflammable oily material. Large capacity vacuum circuit breaker.