JP2009054481A - Gas circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-blast circuit breaker which has improved breaking performance by preventing a gas of high-temperature from staying near the tip part of a small diameter side arc contactor. <P>SOLUTION: An insulation protruding part 5 which has a nearly rotating parabolic shape is installed at the tip part of the stationary arc contactor 1. When the gas is blown onto the arc in arc extinction, this prevents the gas of high-temperature from staying near the tip part of the small diameter side arc contactor 1 and can cool the arc sufficiently by striking a gas flow of high velocity to the arc emitted from the stationary arc contactor 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas circuit breaker for opening and closing an electric circuit, and in particular, a gas having a function of insulating an electric circuit from a ground potential, a function of supplying a load current in a closed state, and a function of cutting off a current during a healthy state and an accident. It relates to circuit breakers.

  The gas circuit breaker performs arc extinguishing by blowing an arc extinguishing gas to an arc generated between the contacts. Gas spraying methods include mechanical puffer systems that mechanically compress gas and increase the gas pressure, and thermal puffer systems that increase the gas pressure by taking in arc energy from the arc. The gas flow generated from the puffer is guided between the contacts, and the gas flow is applied to each contact from there.

  For example, the gas circuit breaker described in Patent Document 1 is configured to guide the gas flow from the mechanical puffer to between the contacts through the gas flow path, and the gas is blown from the blowing port to the arc. ing. The gas flow path communicating with the spray port is formed so as to be perpendicular to the gas circuit breaker drive shaft, the gas ejected from the spray port is divided into two directions, and the stationary contact and movable on both sides are cooled while cooling the arc It flows toward the contact.

  Also, in the case of a conventional gas circuit breaker, the contact on the side having a smaller diameter is, for example, a fixed-side arc contact with respect to the fixed-side arc contact and the movable-side arc contact, and its tip portion takes into consideration insulation. And it has a blunt shape. When the arc is extinguished, the gas flow striking the fixed-side arc contact is decelerated and stagnate near the tip of the fixed-side arc contact. In particular, the gas flowing near the tip is heated by the arc, and high-temperature gas accumulates.

JP 2002-25400 A

  However, the conventional gas circuit breaker has the following problems.

  The gas flow blown to the arc during arc extinction hits the tip of the fixed-side arc contact and decelerates, and high-temperature gas accumulates in the vicinity of the tip, but the high-temperature gas has high conductivity, so the arc Is electrically connected between the movable-side arc contact and the high temperature portion. Therefore, there has been a problem that the insulation distance between the fixed side arc contact and the movable side arc contact is shortened and the insulation is lowered. In addition, it is the arc cooling effect that determines the breaking performance of the circuit breaker. It is the rapid cooling of the arc and the rapid insulation recovery of the arc space, but the arc is cooled because the flow is stagnant. Therefore, there was a problem that an efficient shut-off performance could not be obtained.

  The present invention has been made in view of the above, and is a gas shut-off that can improve the shut-off performance by preventing high-temperature gas from accumulating near the tip of the small-diameter side arc contactor during shut-off. The purpose is to provide a vessel.

  In order to solve the above-described problems and achieve the object, a gas circuit breaker according to the present invention includes a sealed container filled with an arc extinguishing gas, and a first arc contact provided in the sealed container. A second arc contact provided in the sealed container and capable of contacting and separating from the first arc contact and being inserted into the first arc contact in the charged state; and the first and first A gas circuit breaker comprising: a gas flow generating unit that generates a gas flow for extinguishing an arc generated between the two arc contacts; and an insulating nozzle that guides the gas flow to the arc. A projecting portion fixed to the tip of the arc contact and made of an insulating member, and configured so that the area of the fixing surface of the projecting portion is smaller than the cross-sectional area of the base of the second arc contact It is characterized by that.

  According to the present invention, an insulating projecting portion is provided at the tip of the second arc contact so that the area of the fixing surface of the projecting portion is smaller than the cross-sectional area of the base of the second arc contact. Therefore, when a gas flow is blown on the arc during arc extinction, the gas flow flowing in the direction of the second arc contactor is guided to the projecting portion and extends along the side surface from the tip of the second arc contactor. Flows smoothly. Therefore, high temperature gas does not collect at the tip of the second arc contact, and therefore the insulation distance between the first arc contact and the second arc contact is caused by the retained high temperature gas. Since it is not shortened, the insulation at the time of interruption is improved. Further, the arc comes out of the conductor portion near the projecting portion at the tip of the second arc contact, and the gas flow becomes faster in this vicinity, so that the arc can be cooled quickly and sufficiently. In this way, it is possible to promote the discharge of the hot gas in the arc space and to apply a gas flow having a high flow velocity to the arc, and thus the effect of improving the interruption performance is achieved.

  Embodiments of a gas circuit breaker according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of the arc extinguishing chamber in the gas circuit breaker according to the first embodiment, and particularly shows a cross-sectional configuration in the vicinity of the contact in the open state. The gas circuit breaker according to the present embodiment includes a fixed arc contact 1 and a movable arc contact in an airtight container (not shown) filled with an arc extinguishing gas (for example, SF ₆ gas) as an arc extinguishing medium. It comprises a child 2, an insulating nozzle 3, and a puffer (not shown) as a gas flow generator.

  The arc extinguishing chamber is installed in an airtight container filled with arc extinguishing gas. In this arc extinguishing chamber, the fixed arc contact 1 and the movable arc contact 2 are opposed to each other on the same shaft 9. Has been placed. An insulating nozzle 3 is provided so as to surround these arc contacts. The movable arc contact 2 is configured so as to reciprocate in the direction of the axis 9 together with the insulating nozzle 3 by a driving device (not shown). Further, the movable arc contact 2 is provided with a fitting hole 10, and in the inserted state, the fixed arc contact 1 is inserted into the fitting hole 10, and the fixed arc contact 1, the movable arc contact 2, Will be in contact. That is, in the present embodiment, the fixed arc contact 1 is configured to have a smaller diameter than the movable arc contact 2. The fixed arc contact 1 and the movable arc contact 2 need only be movable relative to each other so that the fixed arc contact 1 and the movable arc contact 2 can be moved toward and away from each other. Of course, the structure which fixes the contact 2 is also possible.

  The gas flow path 4 is formed as a region surrounded by the insulating nozzle 3 and the movable arc contact 2, and this gas flow path 4 is connected to a puffer (not shown) on the left side of the figure, When the arc extinguishing gas is compressed and a high blowing pressure is formed, the gas flow flows out to the arc extinguishing chamber through the gas flow path 4.

  The shape of the tip of the fixed arc contact 1 is, for example, a substantially hemispherical shape, and the tip of the fixed arc contact 1 has an insulating protruding portion 5 made of an insulating member protruding in the direction of the movable arc contact 2. Is fixed. The area of the fixed surface is configured to be smaller than the cross-sectional area of the base portion of the fixed arc contact 1. The relationship between the area of the fixed surface and the cross-sectional area of the base of the fixed arc contact 1 is that the diameter d of the fixed surface is about 1/2 to 2/3 of the diameter D of the base of the fixed arc contact 1 in terms of diameter. Preferably there is. In FIG. 1, the fixed surface at the tip of the substantially hemispherical fixed arc contact 1 is formed to be a surface perpendicular to the shaft 9, and the fixed surface that is the center of the tip is A fixing surface is formed in a region defined by a radius smaller than D / 2 from the intersection with the shaft 9.

  As shown in FIG. 1, the shape of the outer surface (that is, the surface other than the fixing surface) of the insulating projecting portion 5 can be, for example, a paraboloid. The rotating parabolic insulating projecting portion 5 has a rotating parabolic tapered portion facing the upstream side (left side in the illustrated example) of the gas flow and is fixed on the end surface on the downstream side (right side in the illustrated example). The axis is aligned with the arc contact 1 and is fixed to the front end surface of the fixed arc contact 1.

  The insulating nozzle 3 is formed mainly of an insulating resin such as tetrafluoroethylene resin. Further, the insulating protruding portion 5 can be formed of the same insulating material as that of the insulating nozzle 3.

  Next, the operation of the present embodiment will be described. Although FIG. 1 shows an open state, the movable arc contact 2 moves to the right and contacts the fixed arc contact 1 in the open state. Below, the operation | movement at the time of reaching a contact open state by interrupting electric current from a making state is demonstrated. When the current is interrupted, the movable arc contact 2 moves to the left in FIG. 1 from the input state, the movable arc contact 2 and the fixed arc contact 1 are separated, and an arc is generated between the arc contacts. In this case, the arc emitted from the fixed arc contact 1 comes out of a conductor portion in the vicinity of the insulating projecting portion 5 (for example, near the symbol B in the figure).

  When the puffer (not shown) is a mechanical puffer, the volume is compressed to increase the pressure of the mechanical puffer chamber. When the puffer (not shown) is a heat puffer, the gas around the arc is heated by the arc energy and the pressure rises, and a part thereof flows into the heat puffer chamber and the pressure of the heat puffer chamber rises. In any case, when the current approaches the zero point, the heating around the arc decreases, so the pressure decreases, and the high-pressure gas stored in the puffer chamber passes through the gas flow path 4 by the induction of the insulating nozzle 3. Sprayed on the arc.

  The gas sprayed to the fixed arc contact 1 side hits the rotating parabolic insulating protrusion 5 while cooling the arc. Since the insulating protruding portion 5 has a shape close to a streamline with respect to the flow, the gas flow flows along the insulating protruding portion 5 without stagnation on the front surface of the insulating protruding portion 5. Accordingly, a gas having a high flow velocity also flows in the vicinity of B where the arc is generated. Moreover, since the shape of the front-end | tip part of the fixed arc contact 1 is a substantially hemispherical shape, the shape of the said front-end | tip part in B vicinity is smooth, and this also contributes to forming the gas flow with a quick flow velocity. .

  Here, the gas flow in the conventional gas circuit breaker will be described. FIG. 3 is a cross-sectional view of an arc extinguishing chamber in a conventional gas circuit breaker, and particularly an enlarged view of the vicinity of the contacts. As shown in FIG. 3, in a conventional gas circuit breaker, 102 is a fixed arc contact, 107 is a movable arc contact, 115 is an insulating nozzle, and the contact on the smaller diameter side is a fixed arc contact 102. ing. The tip of the fixed arc contact 102 has a blunt shape in consideration of insulation. The gas flow hitting such a fixed arc contact 102 decelerates and stagnates near symbol A in the figure. In particular, the gas flowing in the vicinity of A is heated by an arc, and high-temperature gas accumulates. Since the high-temperature gas has high conductivity, the arc is electrically connected to the movable arc contact 107 and the high-temperature portion. In addition, it is the cooling of the arc that determines the breaking performance of the circuit breaker. The arc is quickly cooled and the insulation of the arc space is rapidly recovered. However, the flow is stagnant with the conventional circuit breaker. Therefore, the arc is not cooled, and it is difficult to obtain an efficient interruption performance. On the other hand, in the present embodiment, by providing an insulating protrusion in the vicinity of A where hot gas stays, the hot gas is quickly discharged without staying.

  As described above, according to the present embodiment, by providing the insulating projecting portion 5 at the tip of the fixed arc contact 1, the fixed arc contact when the gas flow is blown to the arc during extinction. The gas flow flowing in one direction is guided by the insulating protrusion 5 and smoothly flows along the side surface from the tip of the fixed arc contact 1. Therefore, high temperature gas does not accumulate at the tip of the fixed arc contact, and therefore the insulation distance between the fixed arc contact 1 and the movable arc contact 2 is shortened by the accumulated high temperature gas. Since there is no, the insulation at the time of interruption | blocking improves.

  Further, the arc exits from the conductor portion in the vicinity of B in FIG. 1, but the gas flow becomes faster in this vicinity, so that the arc can be cooled quickly and sufficiently.

  Further, since the insulating protruding portion 5 is formed of an insulating member, evaporation (so-called ablation) due to arc heat occurs. In particular, when a large current flows, the arc wraps around the insulating protrusion 5 so that gas is generated inside the arc, and the arc is cooled by the flow from the inside of the arc. Thus, the cooling effect is further enhanced. Further, such an evaporated gas is also generated in the insulating nozzle 3, but in the initial stage of opening when the movable arc contact 2 is separated from the fixed arc contact 1, the gas generated by the evaporation of the insulating protrusion 5 is also added. It flows into the puffer and has the effect of increasing the pressure of the puffer, leading to a faster gas flow when the current is interrupted.

  Thus, since there is no high-temperature gas with a slow flow velocity near the fixed arc contact 1 and a gas flow with a high flow velocity directly hits the arc, the arc in the vicinity of the fixed arc contact 1 can be sufficiently cooled. The gas can be efficiently blown onto the arc. Further, since the puffer pressure can be increased by ablation, high-pressure gas can be ejected. Therefore, a highly reliable gas shutoff device with high shutoff performance can be obtained.

Embodiment 2. FIG.
FIG. 2 is a cross-sectional view of the arc extinguishing chamber in the gas circuit breaker according to the second embodiment, and particularly shows a cross-sectional configuration in the vicinity of the contact in the open state.

  In the present embodiment, the configuration of the fixed arc contact 1, the movable arc contact 2, the insulating nozzle 3, and the gas flow path 4 is the same as that of the first embodiment, but the tip of the fixed arc contact 1 is cylindrical. Insulating protrusion 6 is provided.

  The insulating projecting portion 6 extends long in the upstream side of the flow, and its front end surface is located near the gas outlet 7 from the puffer in a state where the opening is completed. Further, it is fixed to the fixed arc contact 1 at the downstream end face with its axis aligned. The area of the fixed surface is smaller than the cross-sectional area of the base portion of the fixed arc contact 1 and smaller than that of the first embodiment, and the diameter d of the fixed surface is equal to the diameter D of the base portion of the fixed arc contact 1 in terms of diameter. It is preferably about 1/2.

  Since other configurations of the present embodiment are the same as the configurations of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  Next, the operation of the present embodiment will be described. Although FIG. 2 shows the open state, the movable arc contact 2 moves to the right and contacts the fixed arc contact 1 in the open state. When the current is interrupted, the movable arc contact 2 moves to the left in the drawing from the input state, the movable arc contact 2 and the fixed arc contact 1 are separated, and an arc is generated between both arc contacts. In this case, the arc emitted from the fixed arc contact 1 comes out of the conductor (near symbol C in the figure) in the vicinity of the insulating protrusion 6.

  During the interruption, the arc space always has an insulator on the axis 9 which is the central axis, so that the arc surrounds the insulating protruding portion 6 at any part of the arc. When the puffer (not shown) is a mechanical puffer, the volume is compressed to increase the pressure of the mechanical puffer chamber. When the puffer (not shown) is a heat puffer, the gas around the arc is heated by the arc energy and the pressure rises, and a part thereof flows into the heat puffer chamber and the pressure of the heat puffer chamber rises. In either method, when the current approaches the zero point, the heating around the arc decreases and the pressure decreases, and the high-pressure gas stored in the puffer chamber is blown to the arc through the gas flow path 4.

  The gas blown to the fixed arc contact 1 side flows along the insulating protruding portion 6 while cooling the arc, and the flow hits the vicinity of C of the fixed arc contact 1. On the other hand, the angle is shallow, and the flow flows along the fixed arc contact 1 without stagnating. Accordingly, a gas having a high flow velocity flows in the vicinity of C where the arc is generated.

  As described above, according to the present embodiment, there is no high-temperature gas having a slow flow velocity in the vicinity of the fixed arc contact 1 and a gas flow having a high flow velocity directly hits the arc. The arc can be sufficiently cooled, and a high-performance gas circuit breaker can be obtained.

  Further, evaporation (so-called ablation) due to the heat of the arc occurs in the insulating protruding portion 6. As a result, gas is generated inside the arc, and the arc is cooled by the flow from the inside of the arc, so that the cooling effect is further enhanced.

  Further, such an evaporated gas is also generated in the insulating nozzle 3, but the gas generated by the evaporation of the insulating protruding portion 6 is also added and flows into the puffer, which has an effect of increasing the puffer pressure and interrupts the current. Sometimes leading to faster gas flow.

  As mentioned above, according to the gas circuit breaker concerning this invention, the gas circuit breaker which has high electric current interruption performance can be provided.

It is sectional drawing of the arc-extinguishing chamber in the gas circuit breaker concerning Embodiment 1 of this invention. It is sectional drawing of the arc-extinguishing chamber in the gas circuit breaker concerning Embodiment 2 of this invention. It is sectional drawing of the arc-extinguishing chamber in the conventional gas circuit breaker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,102 Fixed arc contact 2,107 Movable arc contact 3,115 Insulation nozzle 4 Gas flow path 5,6 Insulation protrusion part 7 Air outlet 9 Shaft 10 Fitting hole

Claims (5)

A sealed container filled with arc-extinguishing gas;
A first arc contact provided in the sealed container;
A second arc contact provided in the sealed container and capable of contacting and separating from the first arc contact and being inserted into the first arc contact in the charged state;
A gas flow generator for generating a gas flow for extinguishing an arc generated between the first and second arc contacts;
An insulating nozzle for directing the gas flow to the arc;
In the gas circuit breaker with
A projecting portion fixed to the tip of the second arc contact and made of an insulating member;
A gas circuit breaker characterized in that the area of the fixed surface of the projecting portion is made smaller than the cross-sectional area of the base portion of the second arc contactor.   The tip end portion of the second arc contact is substantially hemispherical, and the projecting portion is fixed within a region having a predetermined diameter from the center of the tip end portion. Gas circuit breaker.   The gas circuit breaker according to claim 1 or 2, wherein an outer surface of the projecting portion is a paraboloid of revolution.   The gas circuit breaker according to claim 1 or 2, wherein a shape of the projecting portion is a cylinder.   The gas circuit breaker according to any one of claims 1 to 4, wherein the protruding portion is formed of the same insulating material as that of the insulating nozzle.

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