JPH04294021A - Gas circuit breaker - Google Patents

Abstract

PURPOSE:To extinguish the arc generated in the latest period of shutting-off through effective utilization of thermal energy of the arc in the initial period of the opening process. CONSTITUTION:A stationary arc electrode 4 is fixed to one side of an insulative vessel 3 consisting of an insulative substance, and on that side of this electrode 4 nearer a movable arc electrode, a plurality of current limiting plates 5 in approx. funnel form made of insulative substance are installed coaxially in such an arrangement as assuming cylindrical form. This current limiting plate 5 is supported fast by a support part 5a at the periphery of the stationary arc electrode 4 in such an arrangement that the movable arc electrode 1 can move on the axis of the plate 5. Further at the periphery of the plate 5, a plate accommodating chamber 7 is provided in such a construction that a cylindrical magnet 6 consisting of plural sets of magnetic poles N, S in alternate magnetization is molded as included in an insulative substance. This plate accommodating chamber 7 with cylindrical magnet 6 is accommodated in the abovementioned vessel 3, and a pressure boosting chamber 10 is formed between these vessel 3 and chamber 7.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas circuit breaker used in a power system substation or switchyard, and more particularly to a gas circuit breaker with an improved arc extinguishing chamber configuration.

0003

2. Description of the Related Art Gas circuit breakers, which are part of electrical substation equipment, are required to be smaller and have lower driving force as gas insulated equipment is required to be smaller and more reliable. However, most conventional gas circuit breakers are puffer type gas circuit breakers. Although such a puffer type gas circuit breaker can be made smaller, it is necessary to compress the puffer cylinder.
A driving force is required to overcome the reaction force due to the rise in pressure in the puffer chamber, and it has been extremely difficult to reduce the driving force.

[0004] Therefore, the pressure in the pressurizing chamber is increased by utilizing the arc energy generated during the breaking operation of the circuit breaker.
A self-extinguishing gas circuit breaker has been developed that utilizes this pressure to spray arc-extinguishing gas onto an arc generated between arc electrodes.

An example of such a gas circuit breaker will be explained using FIG. 8. Note that FIG. 8 is a diagram showing a state in which the gas circuit breaker is in the middle of shutting off. That is, one end of the cylinder 20 is fixed to a metal end plate 30 surrounded by an insulating outer cylinder (not shown). An opening is formed at the other end of the cylinder 20, and the insulating nozzle 2 is disposed in this opening, and the insulating nozzle 2 is fixed to the cylinder 20 by a nozzle holding part 33. Furthermore, a movable arc electrode 1 and a fixed arc electrode 4 are installed on the axis of the cylinder 20 and the insulated nozzle 2. This fixed arc electrode 4 is composed of a plurality of finger-like contacts 44, one end of which is fixed to the metal end plate 30. Furthermore, support tubes 21 are disposed outside the fixed arc electrode 4 at predetermined intervals. Furthermore, fixed arc electrode 4
A presser spring 46 is inserted between the insulating nozzle 2 and the support tube 21 so that the finger-like contact 44 can be brought into close contact with the outer peripheral surface of the movable arc electrode 1. A gas release passage 16 is formed.

The conventional gas circuit breaker constructed as described above operates as follows. That is, in the closed state, the movable arc electrode 1 and the fixed arc electrode 4 are in contact with each other and are in a conductive state, and the atmosphere inside and outside the cylinder 20 has the same pressure atmosphere. If the opening operation is started for some reason, a driving force (not shown) will cause
The movable arc electrode 1 begins to move upward in the figure, and the cylinder 20
First, an arc 23 is generated between the fixed arc electrode 4 and the movable arc electrode 1.

[0007] Then, the gas in the vicinity of the arc 23 expands due to this arc heat, and the pressure of the gas in this vicinity increases. This pressure rise inside the cylinder 20 occurs until the movable arc electrode 1 is about to separate from the fixed arc electrode 4 and pass through the insulated nozzle 2, and the pressure rise value is increased to a sufficient value compared to the outside of the cylinder 20.

Furthermore, the movable arc electrode 1 is connected to an insulated nozzle 2.
When going outside, the gas in the insulating nozzle 2 and the cylinder 20 is raised to a high pressure, so the gas from the space passes through the gas discharge passage 16 created by the insulating nozzle 2 and the support tube 21 and is blown into the arc 23. The arc 23 is extinguished, and the interrupting operation is completed.

[0009]

[Problems to be Solved by the Invention] However, in the gas circuit breaker that extinguishes the arc by using the thermal energy of the arc as described above, in the high current region at the initial stage of opening, the pressure in the pressurizing chamber increases due to the arc energy. However, if the attenuation rate of the current is large near the current zero point, the arc that occurs at the end of the interruption cannot be extinguished, making it difficult to interrupt the current. In addition, for self-extinguishing gas circuit breakers,
There was a problem in that although it was possible to cut off the current in a large current cutoff region, there was a region where it could not be cut off in a region where the current was at a medium level or lower.

The present invention has been made to solve the problems of the prior art as described above, and its purpose is to effectively utilize the thermal energy of a large current arc at the initial stage of breaking,
At the end of the cutoff, the current is throttled and the current attenuation rate is reduced.
Another object of the present invention is to provide a gas circuit breaker having highly reliable breaking performance from a small current region to a large current region.

[Configuration of the invention]

0012

[Means for Solving the Problems] The present invention provides a method in which a movable arc electrode and a fixed arc electrode, which can freely approach and separate, are arranged facing each other in a general container filled with an arc-extinguishing gas, and the fixed arc electrode is connected to the general container. In a gas circuit breaker disposed in an insulating container provided inside, a current limiting plate made of an insulating material and configured to allow the movable arc electrode to move on its central axis is provided around the fixed arc electrode. , multiple pieces arranged on a coaxial cylinder,
Furthermore, the present invention is characterized in that a current-limiting plate storage chamber is provided around the outer periphery of the current-limiting plate, and includes a plurality of sets of magnets having N and S poles arranged alternately.

[0013]

[Operation] In the gas circuit breaker of the present invention, the arc generated between the fixed arc electrode and the movable arc electrode during the opening operation is rotated by the permanent magnet around the arc when it extends a specified distance, and is rotated in the radial direction. , and acts on the current limiting plate to increase the arc voltage between them. When the electrode opening operation further progresses and the movable arc electrode passes between the current limiting plate housing chamber and the insulating nozzle attached to the insulating container, the gas heated by the arc is stored in the pressurizing chamber. Next, at the current zero point after the movable arc electrode passes through the insulated nozzle, the current is limited by the action of the current limiting plate and the attenuation rate decreases, and at the same time, the pressurized gas absorbs the arc generated at the end of the interruption. The arc can be easily extinguished because it is sprayed onto the surface.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. 1 to 7. Note that the same members as those of the conventional type shown in FIG. 8 are given the same reference numerals, and explanations thereof will be omitted.

In this embodiment, as shown in FIG. 1, a fixed arc electrode 4 is fixed to one surface of an insulating container 3 made of an insulating material. Further, an insulating nozzle 2 is integrally formed in the insulating container 3 on the opposite surface of the fixed arc electrode 4, and the movable arc electrode 1 moves on its central axis to move toward and away from the fixed arc electrode 4. It is configured. In addition,
A communication hole 9 is formed on the back side of the fixed arc electrode 4.

Further, on the movable arc electrode side of the fixed arc electrode 4, a plurality of substantially funnel-shaped current limiting plates 5 made of an insulating material are disposed in a coaxial cylindrical shape. As shown in FIGS. 2 and 3, the current limiting plate 5 is supported and fixed around the fixed arc electrode 4 fixed to the insulating container 3 by a current limiting plate supporting portion 5a, and its central axis is Movable arc electrode 1
is configured so that it can be moved.

Furthermore, a current limiting plate storage chamber 7 is provided around the outer periphery of the current limiting plate 5. As shown in FIG. 4, the current limiting plate storage chamber 7 is constructed by molding a cylindrical magnet 6, which is constructed by alternately magnetizing a plurality of sets of magnetic poles N and S, with an insulator. The current limiting plate storage chamber 7 equipped with this cylindrical magnet 6 is
A pressurizing chamber 10 is housed inside the insulating container 3, and is formed between the insulating container 3 and the current limiting plate storage chamber 7.

Furthermore, a communication hole 7a through which the movable arc electrode 1 passes is formed on the movable side of the current limiting plate storage chamber 7.
The pressurization chamber 10 and the inside of the current limiting plate storage chamber 7 are configured to communicate with each other in the middle cutoff state shown in FIG. 5 . Further, the cylindrical magnet 6 is provided with a plurality of communication holes 8, whereby the current limiting plate storage chamber 7 and the pressure boosting chamber 10 are communicated with each other. Further, the nozzle throat 2a of the insulating nozzle 2 fixed to the movable arc electrode side outside the insulating container 3 allows the entire container (not shown) and the pressurizing chamber 10 to communicate with each other in the final cut-off state in FIG. It is composed of

The gas circuit breaker of this embodiment constructed as described above operates as described below. That is, in the closed state shown in FIG. 1, the fixed arc electrode 4 is connected to a conductor (not shown), and the movable arc electrode 1 is connected to another conductor (not shown). When a cutoff command is received in such a closed state, the movable arc electrode 1 is driven by a drive device (not shown),
Starts the opening operation and moves upward in the figure.

When the movable arc electrode 1 starts operating in this way, an arc 11 is generated between the movable arc electrode 1 and the fixed arc electrode 4, as shown in FIG. When the movable arc electrode 1 further moves upward in the figure, the arc 1
1, a rotational driving force f acts between the fixed arc electrode 4 and the movable arc electrode 1 due to the magnetic flux 12 generated by the cylindrical magnet 6, and a rotational movement is started.

Then, as shown in FIG.
Due to the rotational movement of the arc 11, the arc 11 enters between the current limiting plates 5, and as a result, the arc length is substantially extended and the arc voltage is increased. At the same time, the gas heated by the arc 11 is transferred to the pressurizing chamber 1 through the communication hole 8 formed in the cylindrical magnet 6.
0, and is also discharged into a general container (not shown) through a communication hole 9 formed in the fixed arc electrode 4.

The movable arc electrode 1 further operates, passes through the throat portion 2a of the insulating nozzle 2 fixed to the insulating container 3, moves to the position shown in FIG. 6, and when the current reaches zero point, the pressurizing chamber At 10, hot gas heated by the arc 11 flows out through the nozzle throat 2a into a general container (not shown) and is blown onto the arc 11. Also, at this time, the arc voltage is increased and current limited by the action of the current limiting plate 5, so as shown in FIG. 7, the peak value of the current is suppressed and the attenuation rate of the current is reduced. The arc generated between the movable arc electrode and the fixed arc electrode at the end of the interruption is easily extinguished. Furthermore, since the pressurized gas is also discharged from the communication hole 9 into the entire container, the arc extinguishing effect is further increased.

For example, when interrupting a large current, the current limiting plate 5 has the effect of greatly limiting the current, so even if the maximum short-circuit current flows, when interrupting the current, the current should be set to 40 to 60% of the maximum value. be able to. Therefore, the volume can be designed to be smaller than that of conventionally used pressurization chambers.

[0024] In addition, when interrupting a small current, the conventional pressurization chamber had a large volume, so no pressurization effect could be obtained;
Since the volume of the pressurizing chamber can be reduced to 40 to 60% of the conventional volume, the pressure in the pressurizing chamber 10 can be increased and arc extinguishing becomes possible. Further, since the arc 11 is rotationally driven by the cylindrical magnet 6, the arc 11 can be cooled, and there is also the advantage that it can be easily interrupted.

Furthermore, since the arc 11 is rotated and travels, it is possible to provide an arc extinguishing chamber with less electrode wear compared to conventional arc extinguishing chambers in which the arc remains in a fixed location and the electrode wear is severe. Further, since the hot gas pressurized by the arc 11 has less conductive vapor due to wear of the electrodes, the dielectric strength between the arc electrodes is less likely to decrease even if the hot gas is blown onto the arc 11 at the time of interruption.

As described above, in the gas circuit breaker of this embodiment, rotational driving force is applied to the arc generated between the fixed arc electrode and the movable arc electrode at the initial stage of the opening operation, and the current limiting plate is At the same time, by efficiently guiding the excess hot gas to the pressurizing chamber, the gas pressure in the pressurizing chamber is increased, and this pressure increase is used to connect the movable arc electrode and the fixed arc at the end of the interruption. It becomes possible to extinguish the arc by spraying arc-extinguishing gas onto the arc generated between the electrodes.

[0027]

[Effects of the Invention] As described above, according to the present invention, an arc is generated between the movable arc electrode and the fixed arc electrode at the beginning of the opening operation, and this arc energy is used to reduce the arc generated at the end of the opening operation. It becomes possible to extinguish the arc. In addition, at the beginning of the opening operation, the arc receives rotational driving force and acts on the current limiting plate, thereby limiting the short circuit current. The pressurization chamber can be made more compact than the conventional gas circuit breaker, and a highly reliable gas circuit breaker can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the closed state of an embodiment of the gas circuit breaker of the present invention.

[Fig. 2] A plan view showing a current limiting plate used in the gas circuit breaker of the present invention.

[Figure 3] Cross-sectional view showing the installation state of the current limiting plate shown in Figure 2

[Fig. 4] A cross-sectional view showing a cylindrical magnet used in the gas circuit breaker of the present invention.

[Figure 5] A sectional view showing the gas circuit breaker shown in Figure 1 in the middle of shutting off.

[Fig. 6] A sectional view showing the final stage of interruption of the gas circuit breaker shown in Fig. 1.

[Fig. 7] A diagram showing the current limiting effect in the gas circuit breaker of the present invention.

[Fig. 8] Cross-sectional view showing an example of a conventional gas circuit breaker

[Explanation of symbols]

1...Movable arc electrode 2...Insulated nozzle 3...Insulating container 4...Fixed arc electrode 5... Current limiting plate 5a... Current limiting plate support part 6...Cylindrical magnet 7... Current limiting plate storage room 8, 9...Communication hole 10...pressurization chamber 11...Arc

Claims (1)

[Claims] [Claim 1] In the entire container filled with arc-extinguishing gas,
In a gas circuit breaker, in which a movable arc electrode and a fixed arc electrode that can freely approach and separate are arranged facing each other, and the fixed arc electrode is disposed within an insulating container provided within the overall container, an insulating layer is provided around the fixed arc electrode. A plurality of current-limiting plates are arranged in a coaxial cylindrical shape, and the movable arc electrode is configured to move on the central axis of the current-limiting plate. A gas circuit breaker characterized in that a current limiting plate storage chamber is provided with magnets having N and S poles arranged alternately.