JP2000149691A - Gas-blast circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and low-cost gas-blast circuit breaker which is outstandingly high in arc-resistant property and is hardly lowered in insulation reliability even by a large number of breakings while a required conductivity is ensured. SOLUTION: An arc contact portion at a tip end of an arc contact shoe contains 85% or more of an arc-proof material comprising at least one of W, Re, Ta, Os, Mo, Nb, Ir, Hf, tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide and silicon carbide and a conductive ratio of the contact portion is made to 1% IACS or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-capacity gas circuit breaker and the like used in the power generation and transformation fields and the power receiving field of an electric power system, and more particularly to an improvement technique of an arc contact in an arc-extinguishing chamber. .

[0002]

2. Description of the Related Art FIG. 8 shows, for example, Mitsubishi Electric Technical Report Vol. 5
No. 6. 9, 1982, p. 44-48 "240 /
It is sectional drawing which shows the structure of the conventional puffer type gas circuit breaker 1 described in "300KV-point cut and 550KV two-point tank gas breaker". In the figure, reference numeral 20 denotes an arc-extinguishing chamber provided with a fixed electrode portion 20A and a movable electrode portion 20B.
The details will be described later. Reference numeral 35 denotes an insulating operation rod interlocked with the movable electrode unit 20B, 36 denotes a supporting insulating cylinder, and 37 denotes a fixed electrode unit 2.
The cooling cylinders 38A, 39A, and 40A connected to 0A are conductors, bushings, and terminals, respectively, for leading out the fixed electrode portion 20A, and 38B, 39B, and 40B are conductors, bushings, and the like, respectively, for leading out the movable electrode portion 20B. A terminal 41 is a container containing the above-mentioned constituent members together with the SF ₆ gas 42 as an arc-extinguishing gas. 43
Is an operation device, and 44 is a control box.

Next, the structure of the arc extinguishing chamber 20 will be described with reference to FIG. In the figure, 21 is a fixed arc contact, 22 is a movable arc contact, 23 is a fixed main contact, 24a is a movable main contact, 24b is a puffer cylinder, 25 is a nozzle, 2
6 is a contact, 27 and 28 are shields, 29 is a piston,
30 is a drive rod, 31 is a mounting bracket, 32 is a fixed-side conductor, 3
3 is a movable side conductor, and 34 is an insulating cylinder.

FIG. 10 is a single view of the fixed arc contact 21. In the figure, 21a is an arc contact portion which can be contacted by an arc generated during a breaking operation, 21b is a conductive portion which does not come into contact with the arc, 21c is both parts 21a, 2
1b. The movable arc contact 22 has the same configuration.

Next, the operation, in particular, the shut-off operation of the gas circuit breaker 1 will be described. When the gas circuit breaker 1 is shut off, the movable arc contact 22 of the puffer type arc extinction chamber 20 is separated from the fixed arc contact 21 that has been in contact with the movable arc contact 21 after sliding, and the arc A1 ( FIG. 9) occurs. In contrast,
The gas compressed in the puffer cylinder 24b flows inside the nozzle 25 as shown by the arrow, and the arc A1 is extinguished. During this time, since the two arc contacts 21 and 22 are exposed to extremely high temperature by the high-temperature arc A1, a conductive arc-resistant material is used at the tip. In this example, as shown in FIG. 10, the fixed arc contact 21 contains 50 to 75% of W (tungsten) (the same in weight% hereinafter) and W (tungsten) in the arc contact portion 21 a to which the arc can make contact, and the remainder is Cu ( A sintered alloy of copper (Cu) or Ag (silver) is used.

[0006] The arc contact portions of the conventional fixed arc contact 21 and the movable arc contact 22 made of the above-mentioned materials are greatly damaged in a porous form when a large number of current interruptions of 10 or more times are performed. When the gas circuit breaker 1 is opened and closed regardless of the presence or absence of current interruption, the worn surface is mechanically worn by sliding, and the electric field concentration occurs due to the rough surface of the arc contact portion. And the wear powder B (FIG. 9) adheres to the inner surface of the insulating cylinder 34, and the dielectric strength of the insulating cylinder 34 is greatly reduced.

Since the above-mentioned amount of wear of the arc contact affects the temperature of the heat generating portion, the diameter d1 (FIG. 10) of the fixed arc contact 21 may be increased to reduce the amount of wear. When the diameter of the armature 21 increases, the diameters of the movable arc contact 22 and the puffer cylinder 24b increase, the arc-extinguishing chamber 20 increases in size, the outer shape of the entire gas circuit breaker 1 increases, and the cost also increases. There was a problem.

FIG. 11 is a cross-sectional view showing an arc-extinguishing chamber 46 of another conventional gas circuit breaker described in, for example, Japanese Patent Laid-Open No. 5-2950. In the figure, 46A is a fixed electrode part, 46B is a movable electrode part, 47 is a fixed arc contactor,
47a is an arc contact portion, 47b is a conductive portion, and 47c is a joint portion between both portions 47a and 47b. 48 is a movable arc contact, 49 is a fixed main contact, 50 is a movable main contact, 5
1 is a puffer cylinder, 52 is a nozzle, 53 is a shield, and 54 is a conductor.

In the fixed arc contact 47 in this case, the arc contact portion 47a is formed of a gradient alloy of W having excellent arc resistance and Cu as a good conductor. That is, at the tip, W is 1
At 00%, the Cu content linearly increases toward the root, and becomes 100% Cu at the joint 47c. Thus, the connection with the conductive portion 47b of 100% Cu can be made of Cu-Cu of the same quality.

However, from the viewpoint of arc resistance,
The content of W is small as a whole of the arc contact portion 47a,
Therefore, when the Cu content is large and the slider is exposed to an arc caused by a large number of interruptions of a large current, the sliding portion of the arc contact is greatly worn porous and has the same problem as described above. .

FIG. 12 is a sectional view showing a fixed arc contact 55 used in another conventional gas circuit breaker described in, for example, JP-A-10-12074. In the figure, 55a is an arc contact portion, 55b is a conductive portion, 55c
Is a joint between the two portions 55a and 55b.

In the fixed arc contact 55, the arc contact portion 55a has W, Re, Nb, M having arc resistance.
o, Ta, at least one of carbides and graphite of the plurality of components as a main component,
At least one of a plurality of components including Cu, Ag, Al, and Au is combined to form a 30% IACS (International Ann.
The conductive portion 55b is made of a material mainly containing at least one of Cu, Al, and Au having a conductivity of 50% IACS or more. Here,% IA
CS is a relative conductivity based on Cu defined by (specific resistance of Cu (1.67 μΩ · cm) / specific resistance of target material) × 100.

In this case, it is intended to achieve both arc resistance and conductivity. However, although the material includes a material excellent in arc resistance, it is configured to have a conductivity of 30% IACS or more. , The ratio of low melting point conductive materials such as Cu must be increased, sufficient arc resistance cannot be obtained, and when the large current is interrupted many times, the sliding part of the arc contact becomes porous. In addition, there is a problem in that abrasion powder is generated to cause abrasion powder, thereby lowering insulation reliability.

[0014]

Since the conventional gas circuit breaker, especially its arc contactor, requires a certain level of conductivity to itself, as a result, a sufficient level of arc resistance is obtained. However, there is a problem that the insulation reliability cannot be reduced due to a large number of interruptions, and the cost increases due to an increase in the size of the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has an extremely high arc resistance while ensuring necessary conductivity, and has a high insulation reliability even after a large number of interruptions. An object of the present invention is to obtain a small and inexpensive gas circuit breaker that hardly decreases.

[0016]

In the gas circuit breaker according to the present invention, the arc contact portion of the arc contact tip to which the arc can come into contact is formed by W, Re, Ta, Os, Mo, Nb, Ib.
r, Hf, tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide,
85% of arc-resistant material consisting of at least one of silicon carbide
It contains the above and the remainder is made of a metal material made of a conductive material of at least one of Cu and Ag, and the electric resistance value of a circuit formed by both arc contacts is not more than the reactance value of the circuit. The conductivity of the metal material forming the arc contact portion is set to a predetermined value or more.

Further, in the gas circuit breaker according to the present invention, the arc contact portion to which the arc at the tip of the arc contact can come into contact is formed by tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide. , Rhenium carbide, molybdenum carbide, silicon carbide, and a metal material containing at least two kinds of arc-resistant materials, and the electric resistance value of the circuit formed by both arc contacts is the reactance of the circuit. The electric conductivity of the metal material constituting the arc contact portion is set to a predetermined value or more so as to be equal to or less than the predetermined value.

Further, in the gas circuit breaker according to the present invention, the electric conductivity of the metal material forming the arc contact portion is 1% IAC.
S or more.

Further, in the gas circuit breaker according to the present invention, the arc contact portion to which the arc at the tip of the arc contact can come into contact is formed of W, Re, Ta, Os, Mo, Nb, Ir, Hf,
Arc-resistant material consisting of at least one of tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide, silicon carbide, and at least one of Cu and Ag And a sintered alloy comprising the above arc resistant material as a fine particle arc resistant material having a content of 50% or more and a particle diameter of 1 μm or less.

Further, in the gas circuit breaker according to the present invention, the sliding speed of the two arc contacts during the opening operation of the pair of arc contacts is 6 m / s or more.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The present invention was created as a result of fundamentally reviewing the electrical characteristics required of the arc contact of a gas circuit breaker, that is, an arc-resistant material having a high melting point, particularly as a material composition of the arc contact part of the arc contact. Pursuing the limit of how high the content of conductive materials can be increased from the starting point of the shut-off operation of the gas circuit breaker.First, the configuration centered on the arc-extinguishing chamber will be described below. Later, electrical characteristics required for the arc contact portion in connection with the breaking operation will be described.

FIG. 1 is a sectional view showing an arc-extinguishing chamber 2 of a gas circuit breaker according to Embodiment 1 of the present invention. In the figure,
2A is a fixed electrode part, and 2B is a movable electrode part. Reference numerals 3 and 4 denote a fixed arc contact and a movable arc contact that are configured so as to be able to contact and separate from each other, and 5 and 6a are a fixed main contact and a movable main contact that are configured to be able to contact and separate from each other. The fixed main contact 5 and the fixed main contact 5 are electrically and mechanically integrally connected via a mounting bracket 13 and a fixed-side conductor 14. The movable arc contact 4, the movable main contact 6a, and the puffer cylinder 6b are also integrally formed.

7 is a nozzle, 8 is a contact, 9 and 10 are shields, 11 is a piston, 12 is a driving rod, 15 is a movable-side conductor, 16 is an insulating cylinder, and 17 is an insulating operating rod. It is driven in the axial direction (right and left direction in the figure). In addition, SF ₆ gas, which is an arc-extinguishing gas, is sealed in the container of the gas circuit breaker including the arc-extinguishing chamber 2. A2 is an arc generated between the arc contacts 3 and 4 during the breaking operation.

FIG. 2 is a single view of the fixed arc contact 3, in which 3a is an arc contact portion which can be contacted by an arc generated during the breaking operation, 3b is a conductive portion which does not contact the arc, Reference numeral 3c denotes a joint between the two portions 3a and 3b. The movable arc contact 4 has the same configuration.

The arc contact portion has a high melting point.
For example, an arc-resistant material containing a large amount of W (tungsten: melting point 3420 ° C.) is used. However, as shown in FIG. 3, the amount of wear caused by sliding of the arc contact is greatly affected by the sliding speed. . The amount of wear on the vertical axis in FIG. 3 is a ratio (relative value) with the value at the time of a sliding speed of 8 m / s being 1.0.

As can be seen from FIG. 3, the sliding speed is 6 m / s.
When the value exceeds, the amount of wear due to sliding tends to increase significantly. In a large-capacity gas circuit breaker that requires a large current interruption, it is necessary to consider the amount of wear in these high-speed ranges.

FIG. 4 is a graph showing the relationship between the W content and the amount of wear at the above-mentioned sliding speed of 8 m / s. The wear amount on the vertical axis in FIG. 4 is also a ratio (relative value), and the wear amount at a W content of 70% is 1.0. As can be seen from FIG. 4, when the W content is 85% or more, the wear amount sharply decreases. Therefore, from the viewpoint of abrasion resistance, the alloy contains 85% or more of a high melting point arc-resistant material, and the rest is Cu or Ag.
It can be seen that a good conductive material having a good quality can be used.

As a high melting point arc-resistant material, in addition to W, Re
(Rhenium: melting point 3180 ° C), Ta (tantalum: melting point 3010 ° C), Os (osmium: melting point 2700 ° C),
Mo (molybdenum: melting point 2620 ° C.), Nb (niobium:
Melting point 2470 ° C.), Ir (iridium: melting point 2440)
° C), Hf (hafnium: melting point 2220 ° C), tantalum carbide (melting point 3980 ° C), hafnium carbide (melting point 393)
0 ° C), niobium carbide (melting point 3610 ° C), zirconium carbide (melting point 3450 ° C), titanium carbide (melting point 3070 ° C)
° C), tungsten carbide (melting point 2750 ° C), vanadium carbide (melting point 2650 ° C), rhenium carbide, molybdenum carbide (melting point 2960 ° C), silicon carbide (melting point 2700 ° C)
Is mentioned. Therefore, by employing an arc contact portion having a composition containing at least one of the high-melting-point arc-resistant materials listed above in an amount of 85% or more, it is possible to suppress the amount of wear at the time of interrupting the large current many times to a sufficiently low level. it can.

Incidentally, each of the above arc-resistant materials has a very large specific resistance as compared with Cu or Ag.
When 85% of these arc-resistant materials are contained, the conductivity becomes about 30%.
% IACS or less. As shown in FIG. 4, the higher the content of the arc-resistant material is 85% or more, the lower the wear amount, but the lower the electrical conductivity. Next, the upper limit of the content of the arc-resistant material, that is, the lower limit of the electrical conductivity and the basis for deriving the upper limit will be described.

FIG. 5 is an electrical equivalent circuit of the arc-extinguishing chamber 2. In FIG. 1A, reference numeral 5 denotes a fixed main contact, 6a denotes a movable main contact, 3 denotes a fixed arc contact, and 4 denotes a movable arc contact. Reference numeral 18 denotes an arc contact circuit formed by the two arc contacts 3 and 4 so as to bridge between the two main contacts 5 and 6a. The fixed-side conductor 14 and a part of the puffer cylinder 6b are formed as constituent members thereof.

When the large current is interrupted, first, the fixed main contact 5 and the movable main contact 6a, which have been closed, start to separate, and an arc A3 is generated between the contact portions ( FIG. Next, due to the voltage of the arc A3, the current is commutated to the arc contact circuit 18, and an equivalent circuit at that time is shown in FIG. If the timing of the commutation of the arc current to the arc contact circuit 18 is late and the duration of the arc A3 is long, the contact portions of the main contacts 5, 6a are greatly damaged, and a serious situation occurs.

The difficulty of the commutation of the arc current to the arc contact circuit 18 is determined by the impedance of the arc contact circuit 18 and includes a reactance X and a resistance R. The value of the inductance L of the arc contact circuit 18 is determined by a three-dimensional shape centered on these contacts, and is about L = 0.4 to 0.8 μH. Therefore,
For example, at a frequency of 60 Hz, there is always a reactance X of X = about 150 to 300 μΩ.

On the other hand, the resistance R is determined by the two arc contacts 3,
No. 4, particularly greatly affected by the combined electrical conductivity of the metal material of the arc contact portion having a high resistance. Here, even if the resistance R is made sufficiently small at the expense of the arc resistance, as described above, the reactance X of a substantially constant value exists in the arc contact circuit 18, and the impedance of the arc contact circuit 18 becomes It does not greatly reduce, and hardly contributes to facilitating commutation of the arc current. On the other hand, even if the resistance R is slightly increased to give priority to the arc resistance, the impedance of the arc contactor circuit 18 determined by the combined value of the constant value and the reactance X does not suddenly increase. In other words, the commutation of the arc current to the arc contact circuit 18 does not suddenly become difficult. However, when the value of the resistance R increases beyond the value of the reactance X, the value of the impedance becomes a direction mainly determined by the resistance R, and the increase in the resistance R directly suppresses the commutation operation of the arc current.

From the above, it is most reasonable to adopt a value equivalent to the reactance X as the upper limit value of the resistance R of the arc contactor circuit 18. As described above, the resistance R of the arc contact circuit 18 occupies most of the resistance of the arc contact portion, and when analyzed based on the same three-dimensional shape of each contact as the basis for calculating the inductance L, the above upper limit is obtained. The value was found to correspond to a combined conductivity of the arc contact of approximately 1% IACS.

That is, while containing 85% or more of the above-mentioned one or more high-melting-point arc-resistant materials, the composite electric conductivity is 1%.
By forming the arc contact portion of the arc contact with a material composition equal to or higher than IACS, the contact by the sliding caused by the opening / closing breaking operation can be performed without adversely affecting the commutation operation of the arc current related to the damage of the main contact. The wear of the part can be greatly reduced, and the reliability as a gas circuit breaker can be greatly improved. Furthermore, minute wear amount decreases, downsizing of the equipment by reducing the diameter d ₂ of the arcing contact, it is also possible to reduce the cost.

In the above description, a metal material containing one or more arc-resistant materials is used. However, W, Re, Ta, Os, Mo, N
By using two or more alloys of b, Ir, and Hf, for example, a W-Re alloy, it is possible to improve not only arc resistance but also mechanical performance at high temperatures.

Embodiment 2 FIG. 6 is a single view of the fixed arc contact 19 in the gas circuit breaker according to Embodiment 2 of the present invention. In the figure, reference numeral 19a denotes an arc contact portion, 19b denotes a conductive portion, and 19c denotes a joint portion between the two portions 19a and 19b. is there.

The arc contact portion 19a is made of tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide,
It contains an arc-resistant material made of at least two of rhenium carbide, molybdenum carbide and silicon carbide, and has a synthetic conductivity of 1
% IACS or more.

For example, when two types of tantalum carbide and hafnium carbide are mixed, the melting point is 4215 ° C., which is higher than the melting point of either type of 3980 ° C. or 3930 ° C., and the arc resistance is further improved. When tantalum carbide and niobium carbide are mixed, the melting point is 4000 ° C.
As described above, an excellent arc contact portion can be realized. Furthermore, a mixture of tantalum carbide and niobium carbide or silicon carbide has a negative temperature coefficient of electrical conductivity and a low resistance at high temperatures, so that an excellent arc contact can be constituted by these materials. .

When the above-mentioned carbide arc-resistant materials are applied, carbon or graphite is liberated due to the high temperature caused by the arc, and this acts as a lubricant on the sliding surface of the arc contact to further reduce the amount of wear. There is an effect that it can be reduced.

Embodiment 3 In the third embodiment, a material whose wear resistance is improved by adopting fine particles having a particularly small particle diameter as the arc resistant material is used. Since the outer shape of the arc contact is not different from that of FIG. 6 of the second embodiment, the description will be made with reference to FIG. That is, here, the arc contact portion 19a of the fixed arc contact 19 is made of a sintered alloy of fine particle tungsten (W) and copper (Cu) having a particle diameter of about 1 μm or less centered on several tens nm. I have.
FIG. 7 is a diagram showing the relationship between the W content and the wear amount at a sliding speed of 8 m / s. The wear amount on the vertical axis of FIG. 7 is also a ratio (relative value), and the wear amount at a W content of 50% is 1.0.

As can be seen from FIG. 7, the content of W is 50%
Above, the amount of wear tends to decrease sharply. In the previous embodiment, the particle diameter is usually about 10 μm. However, as in the third embodiment, a metal structure composed of fine particles of 1 μm or less has a grain size of an arc-resistant structure. It is considered that since the material is fine, wear due to abrasion progresses little by little from the surface, and copper having a low melting point is hard to be scattered, so that the metal structure does not become porous and the amount of abrasion decreases. For this reason, the surface is smooth even after a large number of interruptions of the large current, and the amount of abrasion powder generated by sliding of both contacts is greatly reduced. During the production of a sintered alloy, copper, which is a conductive material, is melted and enters between particles of the non-melted particulate arc-resistant material, so that the particle size of copper is less limited.

In the above, as the fine particle arc resistant material,
W has been described, but Re, Ta, Os, Mo, N
Similar effects can be obtained for b, Ir, Hf, tantalum carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide, and silicon carbide. Similar effects can be obtained with Ag as well as Cu as the conductive material. In addition, when various carbides are applied, carbon or graphite is liberated due to the high temperature caused by the arc, which acts as a lubricant on the sliding surface of the arc contact, and has the effect of further reducing the amount of wear.

Further, the content of the arc-resistant material of the fine particles is set to 50% or more, and the content of the conductive material can be increased in the range of forming a sintered alloy with the conductive material. Since the rate increases, the electric resistance of the arc contact becomes small, and the temperature rise of the contact portion can be suppressed, and the commutation of the arc current to the arc contact circuit described above becomes easy. In addition, restrictions on the application to the gas circuit breaker are reduced.

[0045]

As described above, in the gas circuit breaker according to the present invention, the arc contact portions to which the arc at the tip of the arc contact can come into contact are formed by W, Re, Ta, Os, Mo, Nb, Ib.
r, Hf, tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide,
85% of arc-resistant material consisting of at least one of silicon carbide
It contains the above and the remainder is made of a metal material made of a conductive material of at least one of Cu and Ag, and the electric resistance value of a circuit formed by both arc contacts is not more than the reactance value of the circuit. Since the electric conductivity of the metal material constituting the arc contact portion is equal to or higher than a predetermined value, a large amount of the arc-resistant material having a high melting point can be obtained without adversely affecting the commutation operation of the arc current related to the damage of the main contact. By containing it, the amount of wear caused by sliding of the contact portion is greatly reduced, and there is an effect that a highly reliable, compact and economical gas circuit breaker can be provided.

Further, in the gas circuit breaker according to the present invention, the arc contact portion to which the arc at the tip of the arc contact can come into contact is formed by tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide. , Rhenium carbide, molybdenum carbide, silicon carbide, and a metal material containing at least two kinds of arc-resistant materials, and the electric resistance value of the circuit formed by both arc contacts is the reactance of the circuit. Since the conductivity of the metal material constituting the arc contact portion is set to a predetermined value or more so as to be equal to or less than the value, the composite arc resistant without adversely affecting the commutation operation of the arc current related to the damage of the main contact. The melting point of the material is further increased, the amount of wear caused by sliding of the contact part is greatly reduced, and a highly reliable, compact and economical gas circuit breaker can be provided. There is a result.

Further, in the gas circuit breaker according to the present invention, the electric conductivity of the metal material forming the arc contact portion is 1% IAC.
Since it is S or more, an arc contact portion that does not adversely affect the commutation operation of the arc current related to the damage of the main contact can be reliably obtained.

Further, in the gas circuit breaker according to the present invention, the arc contact portion to which the arc at the tip of the arc contact can come into contact is formed of W, Re, Ta, Os, Mo, Nb, Ir, Hf,
Arc-resistant material consisting of at least one of tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide, silicon carbide, and at least one of Cu and Ag Made of a conductive material, and made of a sintered alloy which is a fine particle arc-resistant material having a content of 50% or more and a particle diameter of 1 μm or less in the above-mentioned arc-resistant material. There is an effect that it is possible to provide a gas circuit breaker in which the temperature rise of the portion is low and the commutation of the arc current to the arc contact circuit is easy.

Further, in the gas circuit breaker according to the present invention, the sliding speed of the two arc contacts at the time of the opening operation of the pair of arc contacts is 6 m / s or more. In a large capacity gas circuit breaker, the effect of increasing the frictional force and reducing the amount of wear caused by sliding is remarkably exhibited.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an arc-extinguishing chamber 2 of a gas circuit breaker according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a single unit of the fixed arc contact 3 of FIG.

FIG. 3 is a diagram showing a relationship between a sliding speed and a wear amount in an arc contact portion.

FIG. 4 is a diagram showing the relationship between the W content and the amount of wear in the arc contact portion.

FIG. 5 is a diagram showing an electrical equivalent circuit of the arc-extinguishing chamber 2.

FIG. 6 is a diagram showing a single fixed arc contact 19 in a gas circuit breaker according to Embodiment 2 of the present invention.

FIG. 7 is a diagram showing a relationship between a W content and a wear amount in an arc contact portion according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional gas circuit breaker.

FIG. 9 is a sectional view showing the arc-extinguishing chamber 20 of FIG. 7;

FIG. 10 is a view showing a single unit of the fixed arc contact 21 of FIG. 8;

FIG. 11 is a sectional view showing an arc-extinguishing chamber 46 different from the conventional arc-extinguishing chamber 46 in FIG.

12 is different from the conventional fixed arc contact 5 shown in FIG.
5 is a diagram showing a single unit of FIG.

[Explanation of symbols]

2 arc extinguishing chamber, 3 fixed arc contact, 3a arc contact portion, 3b conductive portion, 4 movable arc contact, 5 fixed main contact, 6a movable main contact, 18 arc contact circuit, 19 fixed arc contact, 19a arc contact,
19b Conductive part.

Continued on front page F term (reference) 4K018 AD03 AD04 AD05 AD06 AD07 KA01 5G001 AA02 AA08 AA13 BB04 CC03 DD03 EE01 FF01 FF06 5G027 AA13 AA26 CA09 5G050 AA01 AA07 AA13 AA17 AA20 AA25 AAA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA EA02

Claims (5)

[Claims] 1. A pair of main contacts that are configured to be able to contact and separate from each other, and a pair of arc contacts that are configured to be able to be connected and separated from each other and are electrically connected in parallel to a circuit of the pair of main contacts. The arc current flowing between the two main contacts that starts the separating operation first is commutated to a circuit formed by the two arc contacts, and then the arc current is separated between the two contacts by separating the two arc contacts. In a gas circuit breaker which performs a breaking operation by extinguishing an generated arc with an arc-extinguishing gas, an arc contact portion at the tip of the arc contact with which the arc can come into contact is formed of W, Re, Ta, Os, Mo, and Nb. , Ir,
Hf, tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide, at least 85% of an arc-resistant material comprising silicon carbide, and the remainder being The arc contact portion is formed of a metal material made of a conductive material of at least one of Cu and Ag, and the electric resistance of a circuit formed by the two arc contacts is equal to or less than the reactance of the circuit. A gas circuit breaker characterized in that the electrical conductivity of the metal material constituting the above is set to a predetermined value or more. 2. A pair of main contacts that are configured to be able to contact and separate from each other, and a pair of arc contacts that are configured to be able to be connected and separated from each other and are electrically connected in parallel with a circuit of the pair of main contacts. The arc current flowing between the two main contacts that starts the separating operation first is commutated to a circuit formed by the two arc contacts, and then the arc current is separated between the two contacts by separating the two arc contacts. In a gas circuit breaker that performs a breaking operation by extinguishing an generated arc with an arc-extinguishing gas, an arc contact portion at the tip of the arc contact that the arc can contact is formed by tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide. , Titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide,
Along with a metal material containing at least two types of arc resistant materials of silicon carbide, the electric resistance value of a circuit formed by the two arc contacts is equal to or less than the reactance value of the circuit. A gas circuit breaker, wherein the electric conductivity of the metal material constituting the arc contact portion is set to a predetermined value or more. 3. The electrical conductivity of a metal material constituting an arc contact portion is set to 1% IACS or more.
Or the gas circuit breaker according to 2. 4. A pair of main contacts that are configured to be able to contact and separate from each other, and a pair of arc contacts that are configured to be able to be connected and separated from each other and are electrically connected in parallel with a circuit of the pair of main contacts. The arc current flowing between the two main contacts that starts the separating operation first is commutated to a circuit formed by the two arc contacts, and then the arc current is separated between the two contacts by separating the two arc contacts. In a gas circuit breaker which performs a breaking operation by extinguishing an generated arc with an arc-extinguishing gas, an arc contact portion at the tip of the arc contact with which the arc can come into contact is formed of W, Re, Ta, Os, Mo, and Nb. , Ir,
Hf, tantalum carbide, hafnium carbide, niobium carbide, zirconium carbide, titanium carbide, tungsten carbide, vanadium carbide, rhenium carbide, molybdenum carbide, at least one of the arc-resistant materials of Cu, Ag A gas circuit breaker comprising a kind of conductive material, wherein the arc resistant material is a sintered alloy of a fine particle arc resistant material having a content of 50% or more and a particle diameter of 1 μm or less. 5. The gas shut-off according to claim 1, wherein a sliding speed of the two arc contacts during the opening operation of the pair of arc contacts is 6 m / s or more. vessel.