JP2008123762A - Gas blast circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable gas blast circuit breaker which evades the generation of metallic vapor and has an excellent breaking performance without damaging the mobility of a valve even when a spring member is exposed to a high temperature gas by protecting the spring member for moving the valve from the high temperature gas in the valve structure of a puffer piston. <P>SOLUTION: A steel cylindrical guide 41 is provided so as to cover the outer circumferential part of a coil spring 24. The cylindrical guide 41 is freely movable in an axial direction together with the extension and contraction of the coil spring 24, that is the opening/closing operation of a valve plate 23, with a spring bearing 25 as an axis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a puffer-type gas circuit breaker in which an insulating gas compressed in a puffer chamber is blown between arc contacts to extinguish the arc, and a gas-type blocker in which a spring-type valve plate is attached to a compression plate of a puffer piston. It is about a vessel.

  In recent years, gas-insulated switchgear using SF6 gas as arc-extinguishing gas has become the mainstream in the field of electric power switches that energize a large current. Among them, the puffer type gas circuit breaker is most often used because the gas circuit breaker is required to cut off a large current such as a short circuit current of the system.

  The puffer type gas circuit breaker forms an arc extinguishing chamber having contacts on the fixed side and the movable side, SF6 gas in the puffer cylinder is compressed by the puffer cylinder during the opening operation, and SF6 is passed through the nozzle to a pair of arc contacts. The gas is blown to extinguish the arc and cut off the current. Here, the basic structure of the puffer-type gas circuit breaker will be specifically described with reference to FIG. FIG. 5 shows a typical configuration of the arc extinguishing chamber of the puffer type gas circuit breaker.

  The arc extinguishing chamber of the puffer-type gas circuit breaker includes a movable part 6 and a fixed part 7. The movable portion 6 and the fixed portion 7 are disposed to face and separate from each other via an insulating cylinder 17 in a gas tank 1 in which SF6 gas is sealed. Among these, the movable part 6 includes a movable main contact 2 and a movable arc contact 4, and the fixed part 7 includes a fixed main contact 3 and a fixed arc contact 5.

  An operation rod 12 is attached to the movable portion 6. A nozzle 8 and a puffer cylinder 9 are fixed to the operation rod 12 together with the movable main contact 2 and the movable arc contact 4, and are driven integrally by the operation device 13. The movable main contact 2 and the nozzle 8 are coaxially attached to the tip of the puffer cylinder 9.

  Further, a puffer piston 10 is provided on the movable portion 6. The puffer piston 10 is slidably inserted into the puffer cylinder 9, and a puffer chamber 11 is formed by these members. The puffer piston 10 is supported by the gas tank 1 via a support insulating cylinder 14, a shield 15 and a movable support 16.

  In the puffer type gas circuit breaker having the above configuration, the main contacts 2 and 3 and the arc contacts 4 and 5 are in contact with each other in a closed state. During the opening operation, the movable part 6 of the arc extinguishing chamber is driven by the operating device 13 in the opening operation direction (right direction in FIG. 5). In the initial stage of the opening operation, the main contacts 2 and 3 are separated from each other, and all currents are transferred to the arc contacts 4 and 5 side. Thereafter, when the arc contacts 4 and 5 are opened, an arc 18 is generated here. At this time, SF6 gas in the puffer chamber 11 is compressed by the puffer piston 10, and the nozzle 8 guides it and blows it to the arc 18, thereby extinguishing the arc 18 and interrupting the current.

  At this time, in order to cut off the large current, it is necessary to open the arc contacts 4 and 5 at high speed while blowing high pressure SF6 gas. For this purpose, the output of the operating device 13 must be increased. Further, since a large amount of SF6 gas must be blown onto the arc 18, it is desirable that the puffer cylinder 9 has a large cross-sectional area. As a result, the size of the arc extinguishing chamber and the entire circuit breaker must be increased. Such an increase in the output of the operating device and an increase in the size of the circuit breaker increase the cost, leading to an economically disadvantageous situation.

  As a puffer-type gas circuit breaker for solving these problems, there is known a puffer type gas circuit breaker that utilizes a pressure increase caused by arc energy generated when a large current is interrupted. This is because the thermal energy of the arc 18 is taken into the puffer cylinder 9 again, the SF6 gas in the puffer cylinder 10 is heated using this thermal energy, the pressure is increased, and the SF6 gas is arc contacted through the nozzle 8. It sprays on 4 and 5 and interrupts | blocks an electric current. An arrow 19 in the figure indicates a gas flow path when the gas blown from the puffer chamber 11 is taken into the puffer chamber 11 again.

  In the gas circuit breaker adopting this method, the amount of gas to be heated is small, that is, the one with a small capacity of the puffer cylinder 9 can raise the gas pressure more effectively. This is also advantageous in reducing the size of the device. In addition, since the area of the puffer cylinder 9 is small, there is an advantage that the reaction force generated during the opening operation can be suppressed to a low level and the output of the opening / closing operation mechanism unit can be reduced. As described above, the gas circuit breaker using the thermal energy of the arc 18 for increasing the gas pressure in the puffer chamber 11 is excellent in miniaturization and has been rapidly spread in recent years.

  By the way, although the shut-off principle of the puffer type gas circuit breaker using the pressure rise due to arc energy is as described above, the actual gas circuit breaker requires the following three operational responsibilities depending on the operation method. ing. That is, a single opening operation (hereinafter referred to as “single-O-operation”), an operation that opens immediately after closing (hereinafter referred to as “-CO-operation”), and “−CO— Is an operation (hereinafter referred to as “O-θ-CO operation”).

  Among these, in the case of performing “-CO-operation”, the contact is closed immediately after being opened, but is immediately opened. However, in the initial stage of the closing operation, the puffer piston 9 and the puffer cylinder 10 are formed. The gas is supplied only into the puffer chamber 11 through the nozzle 8. As described above, when only the gas supply through the nozzle 8 is relied on, there is a possibility that the gas pressure inside the puffer chamber 11 cannot be recovered to the initial state before the O operation of the “-CO-operation” is started.

  When performing the “O-θ-CO operation”, a relatively high temperature gas generated during the first O operation remains between the arc contacts 4 and 5 at the start of the CO operation. There is a possibility that this gas is taken into the puffer chamber 11 by the CO operation. The gas temperature after shut-off varies greatly depending on the cut-off current, rated voltage, arc-extinguishing chamber structure, and time since shut-off, so it cannot be generally stated, but it may have reached several hundred to several thousand degrees Celsius. . Such high-temperature SF6 gas contains many electrons and ions, and is said to deteriorate the shielding performance and insulation performance, and it is not preferable to incorporate a large amount of high-temperature gas into the puffer chamber 11.

  As measures for preventing the gas pressure from recovering as described above and taking in high-temperature gas, a gas circuit breaker in which a spring-type valve is attached to a puffer piston has been proposed (for example, Patent Documents 1 and 2). In such a gas circuit breaker having a spring type valve, the valve is closed during the opening operation to keep the gas secret in the puffer chamber, while the gas is opened in the puffer chamber during the closing operation. It is like that.

  6 to 8 show a typical example of a spring type valve structure in a puffer type gas circuit breaker. Here, FIG. 6 shows a sectional view of the closed state, the opening operation, and a state in which the valve is closed in the opening state, and FIG. 7 is a sectional view of the state in which the valve is opened during the closing operation. The figure is shown. FIG. 8 shows a front view of the valve structure.

  First, the valve structure will be described with reference to FIG. As shown in FIG. 6, the compression plate 21 of the puffer piston 10 has a disk shape, and the disk-like compression plate 21 has a plurality of communication holes 22 that pass through the compression plate 21 and communicate with the inside and outside of the puffer chamber 11. Are provided in the circumferential direction. A disk-shaped valve plate 23 that can close the communication hole 22 is coaxially disposed on the compression chamber 21 on the puffer chamber 11 side.

  The valve plate 23 is attached to the compression plate 21 of the puffer piston 10 by a bolt 26 via a coil spring 24 and a spring receiver 25. In a normal case, the valve plate 23 is fixed by using a plurality of fastening means including a coil spring 24, a spring receiver 25, and a bolt 26, and the valve plate 23 closes the communication hole 22. Is biased in the direction. A gas intake hole 27 communicating with the puffer chamber 11 is formed in the outer peripheral portion of the operation rod 12.

  Next, the operation of the above valve structure will be described. First, as shown in FIG. 6, during the opening operation, the pressure in the puffer chamber 11 is applied to the valve plate 23 in the direction of the arrow X in FIG. For this reason, the valve plate 23 is brought into close contact with the compression plate 21 of the puffer piston 10 to keep the air inside the puffer chamber 11. During the opening operation, the gas pressure in the puffer chamber 11 is increased, so that the high temperature gas is taken in from the gas intake hole 27 on the outer periphery of the operating rod 12 through the gas inflow passage indicated by 19 in the figure.

  On the other hand, during the closing operation, the pressure in the puffer 11 chamber decreases as the volume of the puffer chamber 11 increases. Then, in the compression plate 21 of the puffer piston 10, a differential pressure in the direction of arrow Y in FIG. As a result, a force in the compression direction is applied to the coil spring 24. When the coil spring 24 is compressed, as shown in FIG. 7, the valve plate 23 moves in the direction of arrow Y in FIG. 7, away from the compression plate 21 of the puffer piston 10, and the communication hole 22 is opened. A path 30 (shown in FIG. 7) is formed. For this reason, normal temperature SF6 gas outside the arc extinguishing chamber is supplied into the puffer chamber 11 through the gas inflow passage 30.

Finally, when the closing operation is completed and the pressure in the puffer chamber 11 is restored to the initial state, the valve plate 23 returns to the original position again by the spring force of the coil spring 24. As a result, the valve plate 23 closes the communication hole 22 of the compression plate 21 of the puffer piston 10 and enters a standby state for the next opening operation.
JP 2000-164085 A JP-A-53-117758

  However, the following problems have been pointed out in the above prior art. That is, in order to increase the pressure in the puffer cylinder 9 with the aim of reducing the size of the circuit breaker, reducing the operating force, and improving the breaking performance, the amount of arc energy taken between the arc contacts 4 and 5 is increased, Although the pressure in the cylinder 9 may be increased, in this case, a large amount of high-temperature gas needs to be taken into the puffer chamber 11.

  The high temperature gas is taken in through a gas intake hole 27 provided in the operation rod 12, and the hot gas passes through the compression plate 21 of the puffer piston 10 in the middle of the opening operation, and the high temperature gas is supplied to the valve. Directly sprayed on the spring 24 of the plate 23. As described above, this high-temperature gas reaches a high temperature of several hundred to several thousand degrees Celsius.

  In the conventional spring-type valve structure of the puffer piston, the coil spring 24 is generally used, but its wire diameter is thin and the heat capacity is small. Therefore, the coil spring 24 exposed to the high-temperature gas is instantly melted by the high-temperature gas, and further, the function as a valve may be lost. Moreover, metal vapor is generated by the coil spring 24 being melted. Since this metal vapor is led from the puffer chamber 11 through the nozzle 8 between the interrupting part poles, it becomes a factor that deteriorates the shutoff performance. From this point also, it is problematic that the coil spring 24 is exposed to the high temperature gas. It was.

  The present invention has been proposed in order to solve the above-described problems. The object of the present invention is to protect a spring member for moving a valve from a high-temperature gas in a valve structure of a puffer piston. It is intended to provide a highly reliable gas circuit breaker having excellent shut-off performance by avoiding the generation of metal vapor without impairing the movability of the valve even if the spring member is exposed.

  In order to achieve the above object, according to the present invention, in a container filled with an insulating gas, a blocking portion comprising a pair of contactable main contacts and a pair of contactable arc contacts is provided, A nozzle and a puffer cylinder are fixed to the movable side of the arc contact, and a puffer piston having a compression plate is slidably mounted in the puffer cylinder to form a puffer chamber. The insulating gas is compressed by the compression plate of the puffer piston, and the arc is extinguished by spraying the insulating gas between the arc contacts using the high temperature gas generated by the thermal energy of the arc using the nozzle as a guide. In the puffer-type gas circuit breaker configured as described above, the compression plate of the puffer piston has a plurality of communication holes communicating with the inside and outside of the puffer chamber in the circumferential direction. A valve plate for closing the communication hole is movably attached to a surface of the compression plate of the puffer piston on the side of the puffer chamber so as to be movable by pressure change in the puffer chamber, and the communication hole is formed in the valve plate. A spring member that holds the valve plate is installed so as to close the valve, and a cylindrical guide that protects the spring member from high-temperature gas generated by the thermal energy of the arc is provided on the outer periphery of the spring member. It is what.

  According to the present invention, by providing a cylindrical guide on the spring member for moving the valve plate, the spring member does not melt even when exposed to high-temperature gas, and reliably functions as a valve. Can do. Further, since the metal vapor of the spring member due to melting is not generated, the metal vapor is not guided between the interrupting portion electrodes via the nozzle. Therefore, it is possible to prevent the interruption performance from being deteriorated due to the metal vapor, and it is possible to maintain the excellent interruption performance.

  According to the present invention, the generation of metal vapor is prevented without impairing the mobility of the valve even when the spring member is exposed to high-temperature gas by a very simple configuration in which a cylindrical guide is provided on the spring member for moving the valve. Therefore, it is possible to provide a highly reliable gas circuit breaker having excellent interruption performance.

  Hereinafter, embodiments of the present invention will be specifically described with reference to FIGS. The following embodiment is applied to a gas circuit breaker in which a spring-type valve plate is attached to a compression plate of a puffer piston, as in the conventional examples shown in FIGS. The same members as those shown in FIG.

(1) First Embodiment [Configuration]
A first embodiment according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view showing the valve structure of the first embodiment, and FIG. 2 is a front view. Here, FIG. 1 shows a valve closed state when hot gas is taken into the puffer chamber during the arc extinguishing process during the opening operation.

  As shown in FIGS. 1 and 2, the disk-like compression plate 21 of the puffer piston 10 is provided with a plurality of communication holes 22 for taking in room temperature gas into the puffer chamber 11 during the closing operation. The valve plate 23, the coil spring 24, the spring receiver 25, and the bolt 26 are attached to the side surface of the compression plate 21 of the puffer piston 11 on the puffer chamber 11 side, which is the same as the above-described conventional example.

  The structural features of the first embodiment are as follows. That is, a steel cylindrical guide 41 is provided so as to cover the outer periphery of the coil spring 24. The cylindrical guide 41 is movable in the axial direction along with the expansion and contraction of the coil spring 24, that is, the opening and closing operation of the valve plate 23, with the spring receiver 25 as an axis.

[Function and effect]
In the first embodiment as described above, the coil spring 24 is always covered by the cylindrical guide 41 and the spring receiver 25 provided on the outer periphery of the coil spring 24. Therefore, when a high temperature gas of several hundred to several thousand degrees C is taken into the puffer chamber 11 from the gas intake hole 27 when a large current is interrupted, the coil spring 24 is not directly exposed to the high temperature gas. Can be prevented from melting.

  Therefore, after the valve plate 23 moves so as to open the communication hole 22, when the closing operation is completed and the pressure in the puffer chamber 11 is restored to the initial state, the valve plate 23 is surely secured by the spring force of the coil spring 24. Can be held in its original position. Thus, since the opening / closing function of the valve plate 23 can be maintained, a high-performance shut-off performance can be realized with a simple configuration.

  Furthermore, in the first embodiment, the amount of wear on the surface of the guide 41 can be reduced by using heat-resistant steel instead of the general steel or stainless steel generally used as the constituent material of the cylindrical guide 41. It has the effect of reducing metal vapor, which is a major factor in the deterioration of the shut-off performance.

(2) Second Embodiment [Configuration]
A second embodiment according to the present invention will be described with reference to FIGS. FIG. 3 is a cross-sectional view showing the valve structure of the second embodiment, and FIG. 4 is a front view. Here, FIG. 3 shows a valve closed state when hot gas is taken into the puffer chamber during the arc extinguishing process during the opening operation.

  As shown in FIGS. 3 and 4, in the second embodiment, instead of the cylindrical guide 41 in the first embodiment, a steel thin strip is formed in a spiral shape on the outer periphery of the coil spring 24. A feature is that a plate spring 42 is provided. The plate spring 42 also serves as the coil spring 24.

[Function and effect]
In such a second embodiment, the movable spring member of the valve plate 23 is not a thin wire coil spring 24 having a shape that can be easily melted by high-temperature gas, but a steel strip-like thin plate formed into a spiral shape. A shaped spring 42 can be used. For this reason, the area of the portion in contact with the high-temperature gas is increased, and the heat capacity can be increased.

  Therefore, melting of the plate spring 42 by the high temperature gas can be prevented more reliably. Moreover, since the plate spring 42 plays the role of the cylindrical guide 41, it can be said that the functions of both the cylindrical guide 41 and the coil spring 24 are constituted by one component. Therefore, according to the second embodiment, it is possible to contribute to the reduction of the number of parts.

(3) Other Embodiments The present invention is not limited to the above embodiment, and the material and shape of each member can be appropriately changed. For example, the cylindrical guide 41 is made of copper having a larger heat capacity. It may be made of a material. According to this configuration, since the copper material having a large heat capacity is used as the cylindrical guide 41, the cooling effect of the hot gas is increased. In addition, since the melting point is high, it is difficult to generate metal vapor even when exposed to a high-temperature gas taken in to increase the pressure inside the puffer chamber 11, and it is possible to maintain a high-performance blocking performance. .

  Furthermore, the embodiment which formed the cylindrical guide 41 from the insulating material with high heat resistance is also included. According to such an embodiment, the amount of wear on the surface of the guide 41 exposed to the high-temperature gas is reduced. Further, since the melt is an insulating material, the function of the valve can be maintained without deteriorating the shut-off performance.

Sectional drawing of 1st Embodiment which concerns on this invention. The front view of FIG. Sectional drawing of 2nd Embodiment which concerns on this invention. FIG. 4 is a front view of FIG. 3. The block diagram of the conventional gas circuit breaker. Sectional drawing which shows the state which the valve closed in the valve structure of the puffer piston of the conventional gas circuit breaker. Sectional drawing which shows the state which the valve opened in the valve structure of the puffer piston of the conventional gas circuit breaker. The front view of the valve structure of the puffer piston of the conventional gas circuit breaker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas tank 2 ... Movable main contact 3 ... Fixed main contact 4 ... Movable arc contact 5 ... Fixed arc contact 6 ... Movable part 7 ... Fixed part 8 ... Nozzle 9 ... Puffer cylinder 10 ... Puffer piston 11 ... Puffer chamber 12 ... Operation rod DESCRIPTION OF SYMBOLS 13 ... Operation apparatus 14 ... Support insulation cylinder 15 ... Shield 16 ... Movable support 17 ... Insulation cylinder 18 ... Arc 19 ... Gas flow path 21 ... Compression plate 22 ... Communication hole 23 ... Valve plate 24 ... Coil spring 25 ... Spring receiver 26 ... Bolt 27 ... Gas intake hole 30 ... Gas inflow passage 41 ... Cylindrical guide 42 ... Plate spring

Claims (5)

In the container filled with the insulating gas, there is provided a shut-off portion comprising a pair of contactable and separable main contacts and a pair of contactable and separable arc contacts. A nozzle and a puffer cylinder are provided on the movable side of the arc contacts. A puffer piston having a compression plate is slidably mounted in the puffer cylinder to form a puffer chamber. During opening operation, the insulating gas in the puffer chamber is separated by the compression plate of the puffer piston. In a puffer-type gas circuit breaker configured to extinguish an arc by compressing and using the high temperature gas generated by the thermal energy of the arc to spray the insulating gas between the arc contacts using the nozzle as a guide ,
The compression plate of the puffer piston is formed with a plurality of communication holes in the circumferential direction communicating with the inside and outside of the puffer chamber,
A valve plate for closing the communication hole is attached to a surface of the compression plate of the puffer piston on the puffer chamber side so as to be movable by pressure change in the puffer chamber,
The valve plate is provided with a spring member for holding the valve plate so as to close the communication hole,
A gas circuit breaker characterized in that a cylindrical guide for protecting the spring member from a high-temperature gas generated by the thermal energy of the arc is provided on the outer periphery of the spring member.   The gas circuit breaker according to claim 1, wherein the cylindrical guide is made of steel.   The gas circuit breaker according to claim 1, wherein the cylindrical guide is made of a copper material.   The gas circuit breaker according to claim 1, wherein the cylindrical guide is formed of an insulating material. The cylindrical guide is formed by a steel plate spring,
The gas circuit breaker according to claim 1, wherein the plate-like spring is configured to also serve as the spring member.

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