JP2015133198A - gas circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit excellent cutoff performance even by small driving force in a large current region by suppressing overheat due to arc discharge by utilizing a radiation loss due to metal vapor.SOLUTION: Concerning a mixture ratio of copper in a W/Cu admixture of a movable arc contact 3, a mixture ratio (mass ratio) of a fixed arc contact 4 side is defined as 20%, and a mixture ratio (mass ratio) of a movable arc contact 3 side is defined as 30%. In a state that arc discharge 8 is generated between the movable arc contact 3 and a fixed arc contact 4, tungsten and copper are exposed to high temperature gas, evaporate and become metal vapor together with each other on a surface of the W/Cu an admixture brought into contact with the arc discharge 8 in the contacts 3 and 4. In this case, the copper easily radiates an electromagnetic wave in comparison with the tungsten. Accordingly, thermal energy of the arc discharge 8 can be converted into radiation energy of the copper, and a temperature of the high temperature gas due to the arc discharge 8 is reduced.

Description

  Embodiments described herein relate generally to a gas circuit breaker that uses high-temperature gas generated by arc discharge to boost a puffer chamber.

  In the gas circuit breaker, a tank which is a sealed container filled with an arc extinguishing gas is provided. SF6 gas is mainly used as the arc extinguishing gas filling the tank, but various gases may be mixed and used. In the tank, a fixed contact portion fixed to the inner wall of the tank and a movable contact portion that can be brought into contact with and separated from the fixed contact portion are arranged facing each other on a concentric axis. In the closed state of the gas circuit breaker, the fixed contact portion and the movable contact portion are in contact with each other and conduct current. In the open state of the gas circuit breaker, the fixed contact portion and the movable contact portion are separated from each other to interrupt the current.

  A fixed energizing contact and a fixed arc contact are provided on the fixed contact portion side, and a movable energizing contact and a movable arc contact are provided on the movable contact portion side. An operation rod having a hollow portion is attached to the movable arc contact on the movable contact portion side, and an operation mechanism is connected to the operation rod. The operation mechanism applies a driving force to the movable contact portion via the operation rod to move the movable contact portion in the axial direction.

  In the gas circuit breaker described above, when the fixed contact portion and the movable contact portion are separated, arc discharge occurs between the fixed arc contact and the movable arc contact. Therefore, a puffer-type gas circuit breaker that extinguishes the arc discharge by blowing an arc extinguishing gas is widely used (for example, Patent Document 1).

  In the puffer type gas circuit breaker, a puffer cylinder and a puffer piston that slides in the puffer cylinder are incorporated on the movable contact portion side. The puffer cylinder is driven integrally with the movable contact portion side. Further, a piston support is attached to the puffer piston, and the puffer piston is fixed to the fixed contact portion side through the piston support.

  A puffer chamber is formed from the space surrounded by the puffer cylinder and the puffer piston. The puffer chamber constitutes an arc extinguishing gas accumulating space. Further, an insulating nozzle is attached to the tip of the puffer cylinder so as to surround the arc discharge between the fixed arc contact and the movable arc contact. The insulating nozzle is configured to rectify the arc extinguishing gas in the puffer chamber and inject it into arc discharge.

  In such a puffer-type gas circuit breaker, the puffer cylinder and the puffer piston move so as to relatively approach with the movement of the movable contact portion during the breaking operation. Therefore, the volume in the puffer chamber is reduced, and the arc extinguishing gas in the chamber is compressed and stored in the puffer chamber. When the pressure in the puffer chamber becomes equal to or higher than the pressure corresponding to the breaking capacity at the current zero point, the insulating nozzle rectifies the arc extinguishing gas in the puffer chamber and blows it to the arc discharge. As a result, the arc discharge is extinguished and the current is interrupted.

  In the above-described puffer-type gas circuit breaker, the breaking performance tends to increase as the gas pressure in the puffer chamber increases. Therefore, conventionally, a so-called self-effect puffer type gas circuit breaker has been proposed in which part of the thermal energy of arc discharge is taken into the puffer chamber to increase the gas pressure in the chamber.

  High-temperature gas is generated from the arc discharge between the fixed contact portion and the movable contact portion. In addition to this, the arc extinguishing gas around the arc discharge is also heated by the arc discharge, and thus becomes high-temperature gas. In the self-efficiency method, by taking a part of such high-temperature gas into the puffer chamber, the gas pressure in the puffer chamber before being blown to the arc discharge can be increased efficiently.

  Moreover, in the self-efficiency type puffer type gas circuit breaker, the pressure in the puffer chamber is increased by utilizing the thermal energy of arc discharge, so that the operation mechanism for moving the movable contact portion does not need to exert a large driving force. . Therefore, according to the self-effect puffer type gas circuit breaker, it is possible to exhibit excellent breaking performance and to reduce the driving force of the operation mechanism that moves the movable contact portion.

  By the way, if the electric current which a gas circuit breaker interrupts becomes large, the thermal energy of the arc discharge which generate | occur | produces between contact parts will also become large. Therefore, in the self-powered effect method using the thermal energy of arc discharge, when interrupting a large current, very large thermal energy is taken into the puffer chamber, and the gas pressure in the puffer chamber may become excessively high. .

  When the gas pressure in the puffer chamber becomes excessively high, the movement of the movable contact portion that moves so as to reduce the volume of the puffer chamber becomes slow. That is, when a large current is interrupted, the reaction force to the interruption operation increases, and instead of reducing the driving force of the operating mechanism, a large driving force is required, and the operating mechanism becomes large. Therefore, in the self-efficiency type puffer type gas circuit breaker, the puffer piston is being downsized to suppress an excessive increase in the gas pressure in the puffer chamber.

Japanese Patent Laid-Open No. 9-50747

  In order to efficiently utilize the self-power effect in the self-effect puffer type gas circuit breaker, the movable arc contact, the fixed arc contact, the insulating nozzle and the operating rod are often configured in a compact manner. In addition, in the self-efficiency type puffer type gas circuit breaker, the puffer piston is being downsized to suppress the reaction force to the breaking operation when a large current is cut off. There is a lot to do. As described above, in the self-effect puffer type gas circuit breaker, the operation rod, the insulating nozzle, and the piston support tend to be compact. If these members are made compact, the internal space must be reduced.

  By the way, in the puffer-type gas circuit breaker, the high-temperature gas due to arc discharge not only flows into the puffer chamber but also flows into the internal space of the movable contact portion. More specifically, the hot gas sequentially flows through the insulating nozzle, the operation rod, and the piston support that supports the puffer piston, and finally flows out into the tank.

  As described above, when the internal space included in the movable contact portion is reduced, the volume and the exhaust cross-sectional area are reduced. For this reason, the flow of the hot gas exhaust stagnates in the internal space of the movable contact portion, resulting in a situation where it is difficult to exhaust the internal space. If the high-temperature gas is not smoothly discharged from the internal space of the movable contact portion, the arc discharge temperature becomes higher than that of the conventional one, and it easily falls into an overheated state. The overheating of the arc discharge becomes a factor that makes it difficult to extinguish the arc discharge, and there is a possibility that the interruption performance is lowered.

  The gas circuit breaker according to the present embodiment has been proposed to solve the above problems, and its purpose is to generate metal vapor in the vicinity of the movable contact portion and use the radiation loss due to this metal vapor. Thus, an object of the present invention is to provide a gas circuit breaker capable of exhibiting an excellent breaking performance with a small driving force in a large current region by suppressing overheating due to arc discharge.

In order to achieve the above object, the gas circuit breaker of the present embodiment has the following configuration. That is,
(1) In a sealed container filled with an arc extinguishing gas, a fixed side contact portion having a fixed arc contact and a fixed energization contact, and a movable side contact portion having a movable arc contact and a movable energization contact , Placed facing each other on a concentric axis,
(2) The fixed-side contact portion and the movable-side contact portion are energized when the contact with each other is closed, and an arc is generated between the movable arc contact and the fixed arc contact when the contacts are separated from each other. Configured to generate a discharge,
(3) The movable side contact portion includes an operation rod that drives the movable side contact portion in the axial direction, an insulating nozzle that rectifies the arc-extinguishing gas and blows the arc discharge, and the movable side contact. In a gas circuit breaker provided with a puffer cylinder that is integrally driven and a puffer piston that is slidably installed in the puffer cylinder and moves relative to the puffer cylinder to compress the arc extinguishing gas,
(4) The movable arc contact and the fixed arc contact are made of a mixed material of tungsten and copper,
(5) The mixing ratio of copper in the mixed material of tungsten and copper of the movable arc contactor is set larger than the mixing ratio of copper in the mixed material of tungsten and copper of the stationary arc contactor. And

It is sectional drawing of 1st Embodiment, (a) is the injection | throwing-in state of a gas circuit breaker, (b) is the state in operation | movement of electric current interruption, (c) is the state immediately before electric current interruption. FIG. 3 is an enlarged sectional view showing the principle of the first embodiment. Sectional drawing of 2nd Embodiment.

[First Embodiment]
Hereinafter, an example of the first embodiment according to the present invention will be specifically described with reference to FIGS. 1 and 2. The first embodiment is a self-effect puffer type gas circuit breaker. In FIG. 1, (a) shows a state in which the gas circuit breaker is turned on, that is, a current energization state in a normal state, (b) shows a state during a current interruption operation, and (c) shows a state immediately before the current interruption. FIG. 2 is an enlarged cross-sectional view for illustrating the principle of the first embodiment.

(Constitution)
As shown in FIG. 1, in the puffer-type gas circuit breaker, a movable contact portion A including a cylindrical movable energizing contact 1 and a fixed contact portion B including a fixed energizing contact 2 face each other on a concentric axis. (Opposite in the vertical direction in FIG. 1) and disposed in a tank (not shown) filled with an arc extinguishing gas. The outer peripheral surface of the movable energizing contact 1 and the inner peripheral surface of the fixed energizing contact 2 are arranged so as to be able to contact and separate.

  The movable contact portion A is provided with a movable arc contact 3 on a concentric axis inside the movable energizing contact 1. The fixed contact portion B is provided with a rod-shaped fixed arc contact 4 on a concentric shaft inside the fixed energization contact 2. The fixed arc contact 4 faces the movable arc contact 3, and the outer peripheral surface of the fixed arc contact 4 is disposed so as to be able to contact and separate from the inner peripheral surface of the movable arc contact 3. The fixed arc contact 4 and the movable arc contact 3 are made of a mixed material of tungsten and copper (hereinafter referred to as a W / Cu mixed material) from the viewpoint of electrical conductivity and heat resistance.

  In the movable-side contact portion A and the fixed-side contact portion B, current energization is performed when the movable energizing contact 1 and the fixed energizing contact 2 are in contact with each other. In the movable contact point A and the fixed contact point B, when the movable energizing contact 1 and the fixed energizing contact 2 are separated from each other, the movable arc contact 3 and the fixed arc contact 4 are not connected. Arc discharge 8 is generated.

  In the first embodiment, the copper mixing ratio in the W / Cu mixed material of the movable arc contact 3 is set to be larger than the copper mixing ratio in the W / Cu mixed material of the fixed arc contact 4. There are features. As a specific example of the mixing ratio of copper, the mixing ratio (mass ratio) on the fixed arc contact 4 side is 20%, and the mixing ratio (mass ratio) on the movable arc contact 3 side is 30%. In addition, the mixing ratio of copper is not limited to these numerical values, and can be appropriately selected as long as the mixing ratio of copper in the movable arc contact 3 is larger than the mixing ratio of copper in the fixed arc contact 4. It is.

  The movable contact portion A is provided with an insulating nozzle 5, a puffer cylinder 6 and an operating rod 7 as members that move integrally with the movable energizing contact 1 and the movable arc contact 3. Among these, the movable arc contact 3 and the operation rod 7 are composed of cylindrical members having the same diameter, and are arranged on concentric axes. The movable arc contact 3 is installed on the upper surface side of the end surface of the puffer cylinder 6, and the operation rod 7 is installed on the lower surface side of the end surface of the puffer cylinder 6.

  An insulating nozzle 5 is installed on the upper surface side of the end surface of the puffer cylinder 6 so as to surround the movable arc contact 3 from the outside, and a movable energizing contact 1 is installed outside the insulating nozzle 5. A through hole 6 a is opened on the end surface of the puffer cylinder 6. The insulating nozzle 5 is attached along the outer peripheral portion of the through hole 6a, and the movable arc contact 3 and the operation rod 7 are attached along the inner peripheral portion of the through hole 6a.

  A puffer piston 10 is slidably installed inside the puffer cylinder 6. A puffer chamber 9 is formed by a space surrounded by the inner wall of the puffer cylinder 6 and the puffer piston 10. A cylindrical piston support 12 is attached to the lower surface side of the puffer piston 10, and the puffer piston 10 is fixed to an inner wall portion of a tank (not shown) via the piston support 12.

  The operation rod 7 penetrates the puffer piston 10 from the inside of the puffer chamber 9, and is connected to an operation mechanism (not shown) through an insulating rod (not shown). The operating rod 7 includes a hollow portion 7a and a solid portion 7b. An exhaust hole 11 is provided in the wall surface at the end of the hollow portion 7 a of the operating rod 7.

(Blocking operation)
When the puffer-type gas circuit breaker having the above configuration starts a shut-off operation from the on state, the operating rod 7 and the puffer cylinder 6 move downward in FIG. 1 in response to the driving force from the operating mechanism. In the middle of the shut-off process in FIG. 1B, the movable energizing contact 1 is separated from the fixed energizing contact 2 and the movable arc contact 3 is separated from the fixed arc contact 4 as the puffer cylinder 6 is lowered.

  When the movable arc contact 3 and the fixed arc contact 4 are separated from each other, an arc discharge 8 is generated between the arc contacts 3 and 4. The arc discharge 8 reaches a high temperature state of about 30,000 degrees at the current peak, the arc discharge 8 converges toward the current zero point, and the gas temperature between the arc contacts 3 and 4 gradually decreases. The generation of the arc discharge 8 generates a high-temperature gas, and the surrounding arc extinguishing gas heated by the arc discharge 8 also becomes a high-temperature gas.

  The hot gas generated by the arc discharge 8 flows into the puffer chamber 9 through the through hole 6 a of the puffer cylinder 6. As a result, the gas pressure in the puffer chamber 9 increases. Further, when the puffer cylinder 6 descends with the progress of the shut-off operation, the puffer cylinder 6 and the puffer piston 10 move so as to be relatively closer, and the volume of the puffer chamber 9 is reduced. Therefore, in the puffer chamber 9, the gas whose pressure is increased by the inflow of the high temperature gas is compressed, and the gas pressure can be increased efficiently.

  Thereafter, the arc discharge 8 becomes smaller toward the current zero point in the latter half of the shut-off process, and as shown in FIG. 1C, the puffer chamber 9 becomes a high pressure due to gas inflow from the generation space of the arc discharge 8 and volume reduction. The gas inside is strongly blown to the arc discharge 8 through the insulating nozzle 5. Therefore, arc cooling is particularly promoted at the stagnation point 14 (shown in FIG. 1C) generated in the vicinity of the movable arc contact 3 in the arc discharge 8. Thereby, the arc discharge 8 is extinguished and the current interruption is completed.

  The hot gas exhausted from the space where the arc discharge 8 is generated flows in two directions. One exhaust gas flows from the insulating nozzle 5 along the fixed arc contact 4 as shown by an upward arrow C in FIGS. 1B and 1C, passes through the inside of the fixed contact portion, and is not shown. It flows out into the free space of the tank. The other exhaust gas enters the inside of the middle movable arc contact 3 and the hollow portion 7a of the operating rod 7 as shown by the downward arrow D in FIGS. Through the piston support 12 and flows out to the free space of the tank (not shown).

(Function and effect)
The operational effects of the first embodiment are as follows. That is, as shown in FIG. 2, in the state where the arc discharge 8 is generated between the movable arc contact 3 and the fixed arc contact 4, it is in contact with the arc discharge 8 of the W / Cu mixed material in the contacts 3 and 4. On the surface, tungsten and copper are exposed to high-temperature gas and are evaporated, and both become metal vapor 17.

  Of the metal vapor 17, copper is more likely to radiate electromagnetic waves than tungsten. For this reason, in the vicinity of the movable arc contact 3 where the mixing ratio (mass ratio) of copper is as high as 30%, compared to the vicinity of the fixed arc contact 4 where the mixing ratio (mass ratio) of copper is 20%, There is a lot of radiation of electromagnetic waves. Therefore, in the first embodiment, the thermal energy of the arc discharge 8 can be converted into copper radiant energy, and the temperature of the high-temperature gas due to the arc discharge 8 can be reduced.

  As described above, when a large current is interrupted, a stagnation point 14 is generated in the vicinity of the movable arc contact 3 in the arc discharge 8, and the temperature of the stagnation point 14 is most important for a large current interruption performance, particularly, a thermal interruption performance. Temperature. In 1st Embodiment, the electromagnetic wave 16 radiated | emitted from copper increases by raising the mixing ratio (mass ratio) of copper by the side of the movable arc contact 3 to 30%. For this reason, the thermal energy of the arc discharge 8 is deprived by the radiant energy of the copper vapor. Therefore, the arc temperature at the stagnation point 14 in the vicinity of the movable arc contact 3 is lowered.

  According to such a first embodiment, even if the insulating nozzle 5, the operating rod 7 and the piston support 12 are made compact so that the discharge of the high temperature gas from the internal space of the movable contact portion is delayed, the copper metal vapor By taking the heat energy of the arc discharge 8 using the radiation loss of 17, it is possible to suppress the occurrence of overheating due to the arc discharge 8. Therefore, it is possible to exhibit excellent current interruption performance while reducing the driving force of the operation mechanism. In addition, by making the insulating nozzle 5, the operating rod 7 and the piston support 12 more compact, it is possible to contribute to improving the efficiency of the self-effect and reducing the reaction force to the shut-off operation.

[Second Embodiment]
(Constitution)
A second embodiment will be described with reference to FIG. FIG. 3 shows a state immediately before current interruption. The feature of the second embodiment is that a metal ablation element 15 mainly composed of copper is installed on the inner surface of the operation rod 7. The ablation element 15 is a member that cools the surroundings by latent heat of vaporization when the metal on the surface evaporates. The installation location of the ablation element 15 can be appropriately selected as long as it is a location where the high temperature gas generated by the arc discharge 8 comes into contact.

(Function and effect)
In the second embodiment described above, since the copper metal vapor 17 is generated when the ablation element 15 touches the arc discharge 8, the thermal energy of the arc discharge 8 is converted into the radiant energy of copper and the arc discharge 8. The temperature of the high temperature gas can be lowered. Furthermore, in the second embodiment, there is no need to newly make a movable arc contact 3 having an increased copper mixing ratio, and only the ablation element 15 for lowering the arc temperature of the arc discharge 8 is installed on the inner surface of the operating rod 7. Thus, the above-described effects can be obtained.

[Other Embodiments]
In addition, said embodiment is shown as an example in this specification, Comprising: It does not intend limiting the range of invention. In other words, the present invention can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention.

  These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof in the same manner as included in the scope and gist of the invention. For example, as the material of the movable arc contact 3, a material obtained by mixing a material mainly composed of tungsten with a metal material having a lower evaporation temperature than tungsten may be used.

  Further, the ablation element 15 may be made of a metal material having a lower evaporation temperature than tungsten or a mixed metal material. Here, as an example of the metal whose evaporation temperature is lower than that of tungsten, aluminum, gold, silver, platinum, etc., which are excellent in current carrying capacity, are suitable. Also in the above embodiment, the same effect as the said embodiment can be acquired.

DESCRIPTION OF SYMBOLS 1 ... Movable energizing contact 2 ... Fixed energizing contact 3 ... Movable arc contact 4 ... Fixed arc contact 5 ... Insulating nozzle 6 ... Puffer cylinder 6a ... Through-hole 7 ... Operation rod 7a ... Hollow part 7b ... Solid part 8 ... Arc discharge 9 ... Puffer chamber 10 ... Puffer piston 11 ... Exhaust hole 12 ... Piston support 14 ... Stagnation point 15 ... Ablation element 16 ... Radiated electromagnetic wave 17 ... Metal vapor A ... Movable contact part B ... Fixed contact part

Claims (5)

In a sealed container filled with an arc extinguishing gas, a fixed side contact portion having a fixed arc contact and a fixed energization contact, and a movable side contact portion having a movable arc contact and a movable energization contact are concentric. Placed facing up,
The fixed-side contact portion and the movable-side contact portion are energized when they are in contact with each other, and arc discharge is generated between the movable arc contact and the fixed arc contact when the contacts are separated from each other. Configured to
The movable side contact portion includes an operating rod that drives the movable side contact portion in the axial direction, an insulating nozzle that blows the arc extinguishing gas on the arc discharge, and a buffer that is integrally driven with the movable side contact. In the gas circuit breaker provided with a cylinder and a puffer piston that is slidably installed in the puffer cylinder and moves relative to the puffer cylinder to compress the arc extinguishing gas,
The movable arc contact and the fixed arc contact are made of a mixed material of tungsten and copper,
The gas in which the mixing ratio of copper in the tungsten and copper mixture of the movable arc contact is set larger than the mixing ratio of copper in the tungsten and copper mixture of the fixed arc contact Circuit breaker.   2. The gas circuit breaker according to claim 1, wherein the movable arc contactor or the fixed arc contact is made of a metal material mainly composed of tungsten and having an evaporation temperature lower than that of tungsten. In a sealed container filled with an arc extinguishing gas, a fixed side contact portion having a fixed arc contact and a fixed energization contact, and a movable side contact portion having a movable arc contact and a movable energization contact are concentric. Placed facing up,
The fixed-side contact portion and the movable-side contact portion are energized when they are in contact with each other, and arc discharge is generated between the movable arc contact and the fixed arc contact when the contacts are separated from each other. Configured to
The movable side contact portion includes an operating rod that drives the movable side contact portion in the axial direction, an insulating nozzle that blows the arc extinguishing gas on the arc discharge, and a buffer that is integrally driven with the movable side contact. In the gas circuit breaker provided with a cylinder and a puffer piston that is slidably installed in the puffer cylinder and moves relative to the puffer cylinder to compress the arc extinguishing gas,
A gas circuit breaker characterized in that an ablation element that cools the surroundings by evaporating the surface is installed in at least one of the movable arc contact, the fixed arc contact, the insulating rod, and the operating rod.   The gas circuit breaker according to claim 3, wherein the ablation element is mainly composed of copper.   5. The gas circuit breaker according to claim 3, wherein the ablation element is made of a metal material or a mixed metal material having a lower evaporation temperature than tungsten.

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