Gas circuit breaker

Abstract

To improve the capability of arc extinction in a gas circuit breaker.SOLUTION: In a gas circuit breaker, a columnar stator and a rotor which are coaxially disposed are displaced in an axial direction by operating an opening / closing drive device to bring electrodes of the stator and the rotor into both closed electrode and opened electrode states, and an arc extinction gas is blown to an arc which is generated between the electrodes of the stator and the rotor in the case of an electrode opening operation for shifting from the closed electrode to the opened electrode. Further in the electrode opening operation, at least one insulation movable body which is provided at an arc generation portion protrudes from a side part to a path of the arc. Thus, the path of the arc in the electrode opening operation can be surely extended, and a capability of arc extinction can be improved.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas circuit breaker, and particularly relates to a gas circuit breaker in which interruption is promoted by extending an arc generated during interruption.

Background Art

[0002] A conventional puffer-type gas circuit breaker includes a stationary member on the stationary side of an interruption unit, and a movable member, a nozzle, and a puffer chamber on the movable side of the interruption unit. During the interruption process, the coaxially arranged stationary member and movable member are displaced in the axial direction by the operation of a switching drive device, whereby the respective electrodes of the stationary member and the movable member change from a contact, that is, closed state, to an open state in which the two are separated from each other and become electrically insulated. During the opening operation that transitions from closed pole to open pole, an arc is generated between the two electrodes of the stationary member and the movable member. In a gas circuit breaker, arc-extinguishing gas compressed in the puffer chamber in conjunction with the opening operation of the switching drive device is blown toward the arc from a gas blowing port provided in the nozzle. The arc is cooled by this arc-extinguishing gas, and arc extinction is promoted. The above is the basic operation of a gas circuit breaker, which is disclosed, for example, in Patent Document 1.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0004] Regarding gas circuit breakers, when the interruption voltage is high or when used to interrupt DC circuits, it is necessary to increase the ability to extinguish the arc. Patent Document 1 shows a configuration in which multiple exhaust gas passages are provided on the side of the insulating nozzle located in a position that surrounds the arc during opening operation. By drawing the arc-extinguishing gas into these exhaust gas passages and guiding the arc during interruption into the exhaust gas passages, the arc is extended and the blowing of the arc-extinguishing gas onto the arc is promoted, thereby increasing the arc voltage. However, since it is necessary to actively increase the pressure in the puffer chamber for blowing the gas, measures such as increasing the power of the opening mechanism in order to operate the movable cylinder rapidly are necessary, which leads to increased costs and complexity of the mechanism.

[0005] Another method for improving the arc extinguishing capability is described in Patent Document 2. This method involves forming multiple protrusions on the side surface of the insulating nozzle to create turbulence in the flow of arc-extinguishing gas during opening operation, thereby improving the cooling efficiency of the arc. However, since the fixed arc contact (corresponding to the stator in the present invention) penetrates the inner diameter of the insulating nozzle when the electrode is closed, these protrusions must be made smaller than or equal to the size that does not touch the fixed arc contact, thus limiting the turbulence-promoting effect. Furthermore, if the protrusions are made of the same resin material as the insulating nozzle, the protrusions will gradually wear down due to the heat of the arc during interruption, and there is a risk that the effect will be lost after repeated interruptions. On the other hand, if the protrusions are made of inorganic materials such as resin or ceramic that do not wear down easily, the ablation gas generated inside the insulating nozzle due to the consumption of the resin by the heat of the arc will decrease, and there is a problem that the cooling effect by blowing ablation gas onto the arc will be reduced.

[0006] In view of the above, the problem that the present invention aims to solve is to improve the arc extinguishing ability of a gas circuit breaker. [Means for solving the problem]

[0007] To achieve the above objective, the gas circuit breaker according to the present invention comprises a pair of stators and movable elements arranged on the same axis and movable in the axial direction, a puffer chamber for accumulating arc-extinguishing gas that is blown onto the arc generated when the movable element separates from the stator, and an insulating nozzle that forms a flow path for guiding the arc-extinguishing gas accumulated in the puffer chamber to the arc, wherein the stator is a metal cylinder along the same axis, the nozzle is coupled to the movable element and is movable along the same axis, the inside of the nozzle is a nozzle throat consisting of the movable element and a cylindrical straight section opening on both sides of the movable element, and an expanded section whose diameter expands toward the stator side from one end of the straight section, and a movable part that protrudes into the nozzle throat during the separation process This narrows the cross-sectional area of ​​the nozzle throat. It is characterized by being provided with at least one insulating movable body. [Effects of the Invention]

[0008] According to the present invention, the arc extinguishing capability during opening operation can be improved by reliably extending the arc path. [Brief explanation of the drawing]

[0009] [Figure 1] An embodiment of the gas circuit breaker according to the present invention (cross-sectional view, open state) [Figure 2] An embodiment of the gas circuit breaker according to the present invention (cross-sectional view, closed state) [Figure 3] Another embodiment of the gas circuit breaker according to the present invention (cross-sectional view, open state) [Figure 4] Schematic diagram of turbulence generation by nozzle rings [Best Mode for Carrying Out the Invention]

[0010] The following describes a specific embodiment of the gas circuit breaker according to the present invention. Figure 1 is a cross-sectional view of the gas circuit breaker according to the present invention. It shows the state in which an arc is generated between the stator and the movable element during opening operation. First, the configuration will be described. The stator 1 is a metal rod, and the movable element 2 is a roughly cylindrical metal body that contacts and fits with the stator 1. The movable element 2 is supported so as to be movable in the axial direction relative to the stator 1, and the movable element 2 is driven by the operation of an opening / closing drive device (not shown). The stator 1 and the movable element 2 constitute a switch that is electrically conductive when in contact and insulated when opened. The nozzle 3 is an insulator arranged to surround the stator 1 and the movable element 2, and moves axially together with the movable element 2. Inside the nozzle 3, a nozzle throat 4 is formed, which has a cylindrical space and a roughly conical space whose diameter expands toward the nozzle end. The nozzle throat 4 is also called the arc space and is the space in which an arc is generated between the stator 1 and the movable element 2 during opening operation. The insulating gas blown onto the arc during opening operation is stored in the puffer chamber. The buffer chamber is divided into a mechanical buffer chamber 5a and a thermal buffer chamber 5b. As the movable element 2 moves axially, the volume of the mechanical buffer chamber 5a decreases, increasing the pressure of the insulating gas inside, and consequently increasing the pressure in the adjacent thermal buffer chamber 5b.

[0011] Furthermore, the thermal buffer chamber 5b can store the pressure increased by the arc in the nozzle throat 4 through the spray holes 9 in the nozzle 3. Near the zero point of the current during the shutoff process, the pressure in the nozzle throat 4 falls below the pressure in the thermal buffer chamber 5b, so the insulating gas in the thermal buffer chamber 5b is blown onto the arc through the path in the nozzle 3. The arc is cooled by the insulating gas, and the arc extinguishing is promoted. Fixed current-carrying contacts 6, which are cylindrical metal conductors at the same potential as the stator 1, are arranged to surround the stator 1, and in the closed polarity state, the cylindrical outer surface of the nozzle 3 fits perfectly onto the inner surface of the fixed current-carrying contacts. On the other hand, movable current-carrying contacts 7, which are at the same potential as the movable element 2, are arranged to surround the movable element side end of the nozzle 3, and these are fixed to the movable element 2 and the nozzle 3, and both are movable in the axial direction. A fixed cylinder 8 is arranged on the outer surface of the movable current-carrying contact 7, and when the movable current-carrying contact 7 moves in the axial direction, it moves piston-like along the inner surface of the fixed cylinder 8.

[0012] Here, the nozzle 3 is equipped with at least one nozzle ring 10, which is an insulating movable body with an approximate ring shape. The nozzle ring 10 is made of an insulator such as a fluororesin. Figure 1 shows an example with two nozzle rings 10. The nozzle ring 10 has its ring-shaped axis maintained in approximately the same direction as the axis of the nozzle throat and is also radially movable. This radial movement is due to a biasing part (spring 11 in Figure 1) placed inside the nozzle to act on the nozzle ring 10, the axial movement of the nozzle 3 (described later), and the action of a taper provided at the inner diameter end of the fixed energizing contact 6. In order to produce the above action suitably, the part of the nozzle ring 10 that protrudes from the outer circumference of the nozzle 3 is chamfered or rounded (R-processed) in the direction of movement of the nozzle 3. The nozzle ring 10 is fixed by structural measures (not shown) so that it remains within a predetermined range of motion.

[0013] The outermost shell, which encompasses the components described above, contains a sealed tank (not shown in the diagram) that maintains airtightness inside.

[0014] Next, the operation and function of the nozzle ring 10 during the shut-off operation will be explained. Figure 2 shows a cross-sectional view of the gas circuit breaker according to the present invention described above in the closed state. Note that the spring 11 is not shown in Figure 2. In the closed state, the stator 1 is fitted and in contact with the movable element 2, and the movable energizing contact 7 is fitted and in contact with the fixed energizing contact 6. In the closed state, current flows through the two contact points. In this state, the stator passes through the hole in the nozzle ring 10. In the opening operation, which transitions from the closed state to the open state, first the contact between the movable energizing contact 7 and the fixed energizing contact 6 is lost, and at that point all the current flows through the conductive path of the stator 1 and the movable element 2, which are in contact while sliding. As the movable element 2 moves further, contact with the stator 1 is lost, and an arc is generated between the stator 1 and the movable element 2.

[0015] Furthermore, as the movable element 2 moves and the stator 1 disengages from the hole in the nozzle ring 10, the nozzle ring moves radially along the taper provided at the inner diameter end of the fixed energized contact 6 due to the action of the spring 11. This movement causes the position of the hole in the nozzle ring 10 to shift from the axis of the nozzle throat 4, thus curving and extending the path of the arc generated between the stator 1 and the movable element 2. In order to effectively curve the arc path, it is desirable that the circumference of the hole in the nozzle ring extends beyond the axial centerline of the stator.

[0016] When transitioning from the open state to the closed state, the nozzle ring 10 penetrates the outer wall surface of the nozzle, so the nozzle 3 is inserted into the fixed energizing contact 6. When the protruding portion of the nozzle ring 10 reaches the taper of the inner wall surface at the end of the fixed energizing contact 6, the nozzle ring 10 is pushed by the inner wall surface and retracted into the nozzle 3. At this time, the position of the hole in the nozzle ring 10 reaches a position through which the stator 1 can pass, so the stator 1 passes through the hole in the nozzle throat 4 and the hole in the nozzle ring 4, and comes into contact with the movable element 2.

[0017] An arc at a small current and particularly near a current zero point becomes thinner and is generally difficult to interrupt. Even in such a case, bringing the nozzle ring 10 into contact with the arc allows efficient absorption of heat from the arc for cooling, thereby promoting arc extinction.

[0018] As shown in Figure 1 and Figure 2, if the radial movement directions of the plurality of nozzle rings 10 are not the same but are different, the extension of the arc path can be increased. Furthermore, it is also possible to interrupt the arc path by increasing the radial movable stroke of the hole portion of the nozzle ring 10. An embodiment thereof is shown in Figure 3. Extending the arc path or interrupting the arc path in this manner makes it possible to further promote arc extinction.

[0019] Figure 4 is an enlarged schematic diagram schematically showing the state of the internal airflow in the vicinity of the nozzle ring of Figure 1. As shown in Figure 4, the presence of the nozzle ring 11 makes it possible to generate turbulence in the flow of insulating gas. Increasing turbulence in the vicinity of the arc promotes cooling of the arc through thermal diffusion, thereby enabling improvement of the arc extinction capability.

[0020] In the above description, the case where there are two nozzle rings has been illustrated, but the number may be three or more. The direction in which the plurality of nozzle rings protrude has 360° of freedom around the outer surface of the nozzle 3. In order to effectively elongate the arc, as shown in Figures 1 to 4, the direction may be set such that adjacent nozzle rings protrude substantially alternately. Description of Reference Signs

[0021] 1: Stator 2: Mover 3: Nozzle 4: Nozzle throat (arc space) 5a: Mechanical puffer chamber 5b: Thermal puffer chamber 6: Fixed energizing contact 7: Movable energizing contact 8: Fixed cylinder 9: Blow hole 10: Nozzle ring 11: Spring

Claims

1. A gas circuit breaker that interrupts and restores electric current, A pair of stators and movable elements arranged on the same axis and capable of moving toward and away from each other in the axial direction, A puffer chamber for storing arc-extinguishing gas that is blown onto the arc generated when the movable element separates from the stator during the separation process, An insulating nozzle that forms a flow path for guiding the arc-extinguishing gas, which has been pressurized in the puffer chamber, to the arc, Equipped with, The stator is a metal cylinder aligned along the same axis. The nozzle is coupled to the movable element and is movable along the same axis. The inside of the nozzle is The nozzle throat comprises the movable element and a cylindrical straight section opening on both sides of the movable element, and an expanded section whose diameter expands from one end of the straight section toward the stator, During the separation process, at least one insulating movable body protrudes into the nozzle throat and narrows the cross-sectional area of ​​the nozzle throat portion, Equipped with, The insulating movable body has a hole through which the stator passes when closed, The aforementioned nozzle is The insulating movable body has a groove through which it slides, A biasing part that causes the insulating movable body to protrude into the inside of the nozzle throat, A gas circuit breaker equipped with [a specific feature / feature].

2. The insulating conductor is configured such that the opposite end of the biasing portion can protrude from and be retracted relative to the outer surface of the nozzle. The system includes a cylindrical fixed current-carrying contact that is coaxial with the stator and positioned to surround the stator at a distance from its sides, The aforementioned fixed energized contactor is The inner surface of the cylindrical shape is configured to slide coaxially with the outer surface of the nozzle, The inner surface of the end of the cylindrical movable part has a taper on which the protruding portion of the insulating conductor from the outer surface of the nozzle slides as the nozzle moves in the axial direction. The gas circuit breaker according to claim 1.

3. In the gas circuit breaker according to claims 1 to 2, A gas circuit breaker characterized in that there are multiple insulating conductors, and the protruding movable directions inside the nozzle throat are in different directions so as to alternate with adjacent insulating movable bodies.

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