JP2011054369A - Arc electrode, gas-insulated switchgear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arc electrode in which performance deterioration caused by surface unevenness is suppressed, and to provide a gas-insulated switchgear having the arc electrode. <P>SOLUTION: The arc electrode is an arc electrode used in a gas-insulated switchgear which extinguishes arc generated upon current cut-off, and has a region containing tungsten and copper and one or more layers that are arranged in the region and do not contain tungsten. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an arc electrode and a gas insulated switchgear provided with the arc electrode.

In general, an arc electrode of a gas-insulated switchgear that interrupts a large current is subject to severe wear because it is exposed to a high-temperature (several thousand K) arc. Therefore, in consideration of heat resistance, the arc electrode is formed of a mixture of tungsten and copper or an alloy to suppress wear due to the arc. However, depending on the current interruption conditions, the arc electrode is worn even with the above-described tungsten-copper alloy. When the arc electrode is worn out, a crack is generated on the surface of the arc electrode, and the surface layer falls off.
Therefore, a method of embedding a member having high thermal conductivity in a portion exposed to the arc in order to suppress the lateral development of cracks generated on the surface of the arc electrode and prevent the surface layer from falling off (see Patent Document 1). In addition, a method of providing a slit (see Patent Document 2) has been proposed.

JP 2008-204787 A JP 2008-288185 A

In the above-described method, it is possible to suppress the lateral development of the crack and to prevent the surface layer of the arc electrode from being largely dropped. However, fine removal of the surface layer due to cracks cannot be prevented. For this reason, unevenness due to cracks occurs on the surface of the arc electrode. When irregularities occur on the surface of the arc electrode, the portion where the arc is generated (position on the arc electrode) is not stable, and the performance of the arc electrode (for example, current interruption performance) is reduced.
The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an arc electrode that suppresses a decrease in performance due to surface irregularities and a gas-insulated switchgear including the arc electrode. To do.

  An arc electrode according to an embodiment of the present invention is an arc electrode used in a gas-insulated switchgear that extinguishes an arc generated during current cutting, and is disposed in a region containing tungsten and copper. And one or more layers not containing tungsten.

  In the said structure, since it has the area | region containing tungsten and copper, and 1 or more layers which do not contain tungsten arrange | positioned in the area | region, generation | occurrence | production of the unevenness | corrugation on the surface of an arc electrode can be suppressed. For this reason, the fall of an electric current interruption performance can be suppressed.

An arc electrode according to another embodiment of the present invention is an arc electrode used in a gas-insulated switchgear that extinguishes an arc generated during current cutting, and is made of tungsten, copper, and a metal having a boiling point lower than that of copper. It is characterized by including.
It is characterized by.

  In the said structure, since the metal whose boiling point is lower than copper, copper, and copper is included, generation | occurrence | production of the unevenness | corrugation on the surface of an arc electrode can be suppressed. For this reason, the fall of an electric current interruption performance can be suppressed.

  An arc electrode according to another embodiment of the present invention is an arc electrode used in a gas-insulated switchgear that extinguishes an arc generated during current cutting, and is disposed in a region containing tungsten and copper. And a metal having a boiling point lower than that of copper.

  In the said structure, since it has the area | region containing tungsten and copper and the metal whose boiling point is lower than the copper arrange | positioned in the area | region, generation | occurrence | production of the unevenness | corrugation on the surface of an arc electrode can be suppressed. For this reason, the fall of an electric current interruption performance can be suppressed.

  The metal may be arranged in the form of particles or layers.

  The heat of vaporization of the metal is preferably lower than that of copper.

  ADVANTAGE OF THE INVENTION According to this invention, the arc electrode which suppressed the performance fall resulting from the unevenness | corrugation of the surface, and the gas insulated switchgear provided with this arc electrode can be provided.

It is the figure which showed the structure of the gas insulated switchgear which concerns on 1st Embodiment. It is sectional drawing which showed the arc electrode which concerns on 1st Embodiment. It is sectional drawing which showed the arc electrode after arc discharge. It is sectional drawing which showed the arc electrode which concerns on 2nd Embodiment. It is sectional drawing which showed the arc electrode after arc discharge. It is the figure which showed the characteristic of the metal element. It is sectional drawing which showed the arc electrode which concerns on 3rd Embodiment. It is sectional drawing which showed the arc electrode after arc discharge. It is sectional drawing which showed the arc electrode which concerns on 4th Embodiment. It is sectional drawing which showed the arc electrode after arc discharge.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram illustrating a configuration of an insulating gas switching apparatus 100 according to the first embodiment.
The gas insulated switchgear 100 includes a grounding container 1, a fixed electrode 2 (arc electrode), a movable electrode 3 (arc electrode), an insulator 4, a driving device 5, a grounding conductor 6, and a grounding wire 7.

  The ground container 1 is a sealed container in which an insulating gas 7 is enclosed. A fixed electrode 2 and a movable electrode 3 are disposed opposite to each other inside the ground container. The fixed electrode 2 is supported and fixed to a ground container 1 having a ground potential via an insulator 4. In addition, the movable electrode 3 is supported by the ground container 1 via the insulator 4 and is connected to a drive rod (not shown) provided in the drive device 5. The drive device 5 drives the movable electrode 3 in the vertical direction by a drive rod (not shown). When the movable electrode 3 is driven up and down, the movable electrode 3 and the fixed electrode 2 are brought into electrical contact or non-contact state. The ground conductor 6 is supported by the ground container 1 through the insulator 4. One end of the ground conductor 6 is connected to the movable electrode 3, and the other end is grounded via the ground line 7.

  When the movable electrode 3 is driven by the driving device 5 and the fixed electrode 2 and the movable electrode 3 are changed from the contact state to the non-contact state, an arc is generated between the fixed electrode 2 and the movable electrode 3. In the gas insulated switchgear 100 according to the first embodiment, the arc is extinguished by blowing an insulating gas onto the arc.

  FIG. 2A is a cross-sectional view showing the configuration of the fixed electrode 2. Here, the configuration of the fixed electrode 2 will be described with reference to FIG. 2A. The fixed electrode 2 according to the first embodiment is formed of tungsten (W) particles 12 (particle diameter of several tens of μm) and copper (Cu) 13 particles (particle diameter of several tens of μm). As shown in FIG. 2A, the fixed electrode 2 has a region including the tungsten particles 12 and the copper 13, and one or more copper layers 14 not including the tungsten particles 12 disposed in the region.

The fixed electrode 2 is created by the following procedure.
1. A region including the tungsten particles 12 is formed.
2. A copper thin plate is placed on the peripheral surface of the formed region.
3. Repeat steps 1 and 2 as necessary.

  As described above, after repeating the operation of disposing the copper thin plate on the region containing the tungsten particles 12, the powder is compression-molded and sintered by the sintered powder metallurgy method. In FIG. 2A, the copper thin plate is disposed on a part of the peripheral surface of the region including the tungsten particles 12, but the copper thin plate may be disposed on the entire peripheral surface of the region including the tungsten particles 12.

  Tungsten (W) has a very high melting point of about 3700K. Therefore, in the first embodiment, a sintered powder metallurgy method in which tungsten particles 12 (particle size of several tens of μm) having a particle size of several tens of μm and copper 13 particles (particle size of several tens of μm) are compression-molded and sintered. Is used to form the fixed electrode 2.

  A resin or the like may be disposed on the region including the tungsten particles 12 instead of the copper thin plate. If sintering is performed at a temperature at which the copper 13 is melted, the resin is replaced with the molten copper 13, and as shown in FIG. 2A, a copper layer 14 without the tungsten particles 12 is formed. Moreover, since the base 11 is not exposed to an arc, it is not necessary to consider heat resistance. For this reason, the base metal 11 is formed of iron (Fe) or copper (Cu) having high electrical conductivity.

  In addition to the powder metallurgy method, the fixed electrode 2 may be formed by pouring molten copper into the mold after filling the tungsten particles 12. Alternatively, the fixed electrode 2 may be formed by melting both tungsten and copper.

  FIG. 2B is a cross-sectional view showing the fixed electrode 2 after arc discharge (after current interruption). Here, the wear of the fixed electrode 2 according to the first embodiment will be described with reference to FIG. 2B. When the movable electrode 3 is driven by the driving device 5 and the fixed electrode 2 and the movable electrode 3 are in electrical contact, the fixed electrode 2 and the movable electrode 3 are not in electrical contact, that is, fixed. The current flowing through the electrode 2 and the movable electrode 3 is cut off.

  Then, an arc is generated between the fixed electrode 2 and the movable electrode 3. In the portion of the fixed electrode 2 exposed to the arc, the surface tungsten particles 12 are evaporated and melted. Further, the copper 13 having a boiling point lower than that of tungsten evaporates and melts from the tungsten particles 12 to the inside. For this reason, in the part exposed to the arc of the fixed electrode 2, an unevenness | corrugation is formed in the surface. As the fixed electrode 2 evaporates and melts, the unevenness formed on the surface increases.

  However, when evaporation or melting of the fixed electrode 2 proceeds to the copper layer 14, the tungsten particles 12 remaining on the outer side (surface side) of the copper layer 14 fall off. For this reason, the unevenness | corrugation currently formed in the surface of the fixed electrode 2 is planarized, and it can suppress that the unevenness | corrugation formed in the surface becomes large.

  As described above, since the fixed electrode 2 according to the first embodiment can effectively suppress the formation of irregularities on the electrode surface, the performance of the arc electrode caused by the irregularities (for example, the current interruption performance) ) Can be suppressed. In the above description, the fixed electrode 2 has been described. However, if the same configuration is adopted for the movable electrode 3, the same effect as that of the fixed electrode 2 can be obtained.

(Second Embodiment)
FIG. 3A is a cross-sectional view showing a fixed electrode 2A (arc electrode) of an insulating gas switchgear 200 according to the second embodiment. Here, the configuration of the fixed electrode 2A will be described with reference to FIG. 3A. Note that the same components as those described in FIG. 2A are denoted by the same reference numerals, and redundant description is omitted. The configuration of the insulating gas switchgear 200 according to the second embodiment is the same as that of the insulating gas switchgear 100 described with reference to FIG.

  The fixed electrode 2A according to the second embodiment is formed from a mixture 13A of tungsten particles 12, copper 13, and a metal having a boiling point lower than that of copper (hereinafter referred to as a low boiling point metal). The fixed electrode 2A can be formed by a powder metallurgy method or the like as in the first embodiment. In the second embodiment, considering the electrical conductivity, the content of the low boiling point metal with respect to copper is about 10% by weight. In addition, although electrical conductivity becomes low, the mixture 13A may not be a mixture with copper, but only a low boiling point metal.

  FIG. 3B is a cross-sectional view showing fixed electrode 2A after arc discharge (after current interruption). Here, the wear of the fixed electrode 2A according to the second embodiment will be described with reference to FIG. 3B. Similarly to the description in FIG. 2B, when the current flowing through the fixed electrode 2A is interrupted, an arc is generated in the fixed electrode 2A. In the portion of the fixed electrode 2A exposed to the arc, the surface tungsten particles 12 are evaporated and melted. Further, the mixture 13A having a boiling point lower than that of tungsten is also evaporated and melted.

  Here, the low boiling point metal contained in the mixture 13A has a boiling point lower than that of copper. For this reason, the amount of gas generated when evaporating increases compared to the case of only copper. The generated large amount of gas blows off the tungsten particles 12 remaining on the surface side and drops them off. For this reason, it can suppress that the unevenness | corrugation of a surface layer becomes large, and can suppress the performance fall of the arc electrode resulting from this unevenness | corrugation. Moreover, the temperature rise of 2 A of fixed electrodes can be reduced because the low boiling point metal contained in the mixture 13A vaporizes.

  FIG. 4 is a diagram showing the characteristics (melting point, heat of fusion, boiling point, heat of evaporation) of the metal element. In the second embodiment, it is preferable to use a metal having a boiling point and evaporation heat shown in FIG. 4 lower than that of copper as the low boiling point metal. Among these, Cs (cesium), Hg (mercury), K (potassium), Rb (rubidium), and Sb (antimony) having a boiling point as low as about 1000 K are particularly preferable as low boiling point metals.

  As described above, the fixed electrode 2A according to the second embodiment can effectively suppress the formation of irregularities on the electrode surface. For this reason, the performance fall of the arc electrode resulting from an unevenness | corrugation can be suppressed. Moreover, the temperature rise of 2 A of fixed electrodes can be reduced because the low boiling point metal contained in the mixture 13A vaporizes. In the above description, the fixed electrode 2A has been described. However, if the same configuration is adopted for the movable electrode, the same effect as that of the fixed electrode 2A can be obtained.

(Third embodiment)
FIG. 5A is a cross-sectional view showing a fixed electrode 2B (arc electrode) of an insulating gas switchgear 300 according to the third embodiment. Here, the configuration of the fixed electrode 2B will be described with reference to FIG. 5A. Note that the same components as those described in FIG. 2A are denoted by the same reference numerals, and redundant description is omitted. The configuration of the insulating gas switchgear 300 according to the third embodiment is the same as that of the insulating gas switchgear 100 described with reference to FIG.

  The fixed electrode 2B according to the third embodiment includes a region containing tungsten particles 12 and copper 13, and a particle 15 (hereinafter referred to as a low boiling point metal) made of a metal having a boiling point lower than that of the copper 13 disposed in the region. (Referred to as particles 15). The size (diameter) of the particles 15 is preferably sufficiently larger than that of the tungsten particles 12 (in consideration of the size of the electrode (maximum φ50), preferably about 0.1 mm to 1 mm). The fixed electrode 2B can be formed by a powder metallurgy method or the like as in the first embodiment. As for the material of the low boiling point metal particles 15, it is preferable to use Cs (cesium), Hg (mercury), K (potassium), Rb (rubidium), and Sb (antimony) as in the second embodiment. In addition, since Hg is a liquid at normal temperature, it is convenient to handle if it is an alloy (amalgam) with another metal.

  FIG. 5B is a cross-sectional view showing the fixed electrode 2B after arc discharge (after current interruption). As shown in FIG. 5B, similarly to the fixed electrode 2A according to the second embodiment, the gas generated when the low boiling point metal particles 15 evaporate also in the fixed electrode 2B according to the third embodiment. Then, the tungsten particles 12 remaining on the surface side are blown off and dropped off. For this reason, it can suppress that the unevenness | corrugation of a surface layer becomes large, and can suppress the performance fall of the arc electrode resulting from this unevenness | corrugation. Moreover, it can suppress that the temperature of the fixed electrode 2B rises because the low boiling point metal particle 15 vaporizes.

(Fourth embodiment)
FIG. 6A is a cross-sectional view showing a fixed electrode 2C (arc electrode) of an insulating gas switchgear 400 according to the fourth embodiment. Here, the configuration of the fixed electrode 2C will be described with reference to FIG. 6A. Note that the same components as those described in FIG. 2A are denoted by the same reference numerals, and redundant description is omitted. The configuration of the insulating gas switchgear 400 according to the fourth embodiment is the same as that of the insulating gas switchgear 100 described with reference to FIG.

  The fixed electrode 2C according to the fourth embodiment includes a region containing tungsten particles 12 and copper 13, and a layer 16 (hereinafter referred to as a low boiling point metal) made of a metal having a boiling point lower than that of the copper 13 disposed in the region. Referred to as layer 16). The fixed electrode 2C can be formed by a powder metallurgy method or the like as in the first embodiment. As the material of the low boiling point metal layer 16, it is preferable to use Cs (cesium), Hg (mercury), K (potassium), Rb (rubidium), and Sb (antimony) as in the second embodiment. The low boiling point metal layer 16 may have the same arrangement as the copper layer 14 shown in FIG. 2A.

  FIG. 6B is a cross-sectional view showing fixed electrode 2C after arc discharge (after current interruption). As shown in FIG. 6B, similarly to the fixed electrode 2A according to the second embodiment, the gas generated when the low boiling point metal layer 16 evaporates also in the fixed electrode 2C according to the fourth embodiment. Then, the tungsten particles 12 remaining on the surface side are blown off and dropped off. For this reason, it can suppress that the unevenness | corrugation of a surface layer becomes large, and can suppress the performance fall of the arc electrode resulting from this unevenness | corrugation. Moreover, it can suppress that the temperature of 2 C of fixed electrodes rises because the low boiling point metal layer 16 vaporizes.

  DESCRIPTION OF SYMBOLS 1 ... Ground container, 2 ... Fixed electrode (arc electrode), 3 ... Movable electrode (arc electrode), 4 ... Insulator, 5 ... Drive apparatus, 6 ... Ground conductor, 7 ... Ground wire, 11 ... Base metal, 12 ... Tungsten particles, 13 ... copper, 14 ... copper layer, 15 ... low boiling point metal particles, 16 ... low boiling point metal layer, 100 to 400 ... gas insulated switchgear.

Claims (7)

An arc electrode used in a gas-insulated switchgear that extinguishes an arc generated when current is cut off,
An arc electrode comprising: a region containing tungsten and copper; and one or more layers not containing tungsten disposed in the region. An arc electrode used in a gas-insulated switchgear that extinguishes an arc generated when current is cut off,
An arc electrode comprising tungsten, copper and a metal having a boiling point lower than that of copper. An arc electrode used in a gas-insulated switchgear that extinguishes an arc generated when current is cut off,
An arc electrode comprising: a region containing tungsten and copper; and a metal having a boiling point lower than that of copper disposed in the region.   The arc electrode according to claim 3, wherein one or more particles made of the metal are arranged in the region.   The arc electrode according to claim 3, wherein one or more layers of the metal are disposed in the region.   The arc electrode according to any one of claims 3 to 5, wherein the heat of vaporization of the metal is lower than the heat of vaporization of the copper. A container filled with insulating gas;
A fixed electrode and a movable electrode disposed opposite to each other in the container;
A drive unit for driving the movable electrode;
Comprising
7. The gas insulated switchgear according to claim 1, wherein at least one of the fixed electrode and the movable electrode is an arc electrode according to claim 1.

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