JP5286569B2 - Puffer type gas circuit breaker - Google Patents

Description

  The present invention relates to a puffer type gas circuit breaker that performs an arc extinguishing by blowing an insulating arc extinguishing gas using an insulating nozzle.

  In general, a puffer type gas circuit breaker has a fixed arc contact and a movable arc contact arranged coaxially so as to be able to contact and separate, and is housed in a sealed tank filled with an insulating arc-extinguishing gas such as SF6 gas. A cylindrical insulating nozzle is provided so as to surround the space between the contact and separation portions of the fixed arc contact and the movable arc contact. When the current is interrupted, the insulating arc-extinguishing gas is compressed by the compression device while the insulating nozzle is compressed. Is used to guide and blow the arc generated by the separation of the fixed side arc contactor and the movable side arc contactor to extinguish the arc (see, for example, Patent Document 1).

  Also, as an insulating nozzle for guiding the insulating arc-extinguishing gas, an insulating nozzle is formed entirely with a composite material in which an inorganic filler is added to a resin having lower heat resistance than fluororesin, and the ablation effect of the resin material, that is, the arc energy. It is known to improve the shut-off performance by increasing the pressure inside the insulating nozzle by using the ablation gas generated by evaporation of the resin material of the insulating nozzle due to (see, for example, Patent Document 2) ).

JP-A-7-296689 JP-A-2005-332745

  However, in recent years, it has been required to improve the breaking performance due to the demand for increasing the breaking capacity of the puffer type gas circuit breaker and the miniaturization of the equipment, and actively utilizing the ablation effect as shown in Patent Document 2 If you try to do so, the pressure in the insulated nozzle will rise more than necessary due to the ablation effect from the beginning of the arc, and this will act as a reaction force on the actuator. Has been found to adversely affect the shut-off performance.

  An object of the present invention is to provide a puffer-type gas circuit breaker that improves the breaking performance by utilizing the ablation effect while preventing the speed reduction at the beginning of the breaking operation.

  In order to achieve the above-mentioned object, the present invention provides a fixed arc arc contactor and a movable arc contactor, which are disposed in a sealed tank filled with an insulation arc-extinguishing gas, in a separable manner, and an insulation arc-extinguishing gas at the time of shut-off operation. A compressing device for compressing, and an insulating arc-extinguishing gas compressed by the compressing device provided so as to surround a contact portion of the fixed arc contact and the movable arc contact between the fixed arc contact and the movable arc contact; In the puffer type gas circuit breaker provided with an insulating nozzle that guides the arc generated by the separation of the gas, the insulating nozzle is disposed on the upstream side of the blowing gas and on the downstream side of the blowing gas. The upstream portion is formed of a resin material having a low ablation effect, and the downstream portion is more ablated than the upstream portion. Characterized by being formed with a high resin material.

  According to the puffer type gas circuit breaker of the present invention, the ablation effect is relatively suppressed in the upstream portion of the blowing gas flow that is first exposed to the arc during the interruption operation, so that the reaction force against the operating device is reduced. The acceleration of the moving part of the blocking part at the beginning of the blocking operation is increased and the acceleration of the moving part is increased.On the other hand, the ablation effect is added in the downstream part of the blowing gas flow that is exposed to the arc at the end of the blocking operation. Since it is sometimes sufficiently accelerated, it is possible to improve the shut-off performance by effective blowing by utilizing the ablation effect while suppressing the stagnation of the shut-off action due to the reaction force at the pressure peak.

FIG. 1 is a cross-sectional view illustrating a puffer-type gas circuit breaker according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a state in which the puffer type gas circuit breaker shown in FIG. FIG. 3 is a cross-sectional view showing the overall configuration of the puffer type gas circuit breaker shown in FIG. 4 is a cross-sectional view showing an insulating nozzle which is a main part of the puffer type gas circuit breaker shown in FIG. FIG. 5 is a pressure characteristic diagram during a shut-off operation by the puffer-type gas circuit breaker shown in FIG.

Hereinafter, a puffer type gas circuit breaker according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 3 is a cross-sectional view showing the overall configuration of the puffer-type gas circuit breaker, which is configured in a metal tank 1 filled with an insulating arc-extinguishing gas. Both ends of the blocking portion are led out from the metal tank 1 while being insulated from the metal tank 1 by center conductors 2 and 3 of insulation lead-in means (not shown), and a cylindrical exhaust tube 4 is supported and fixed to the center conductor 2. A fixed conductor 14 is supported and fixed to the center conductor 3. A fixed arc contact 5 is fixed to the center of the exhaust tube 4, and a fixed main contact 6 arranged so as to surround the fixed arc contact 5 is fixed to the end of the exhaust tube 4. A movable arc contact 7 that is brought into contact with the fixed arc contact 5 in the charged state is disposed at the tip of the fixed arc contact 5, and the movable arc contact 7 is fixed to a puffer cylinder 9. The puffer cylinder 9 includes an insulating nozzle 11 disposed so as to surround a contact portion between the movable arc contact 7 and the fixed arc contact 5, and a fixed main contact in an inserted state disposed on the outer periphery of the insulating nozzle 11. The movable main contact 8 that contacts with 6 is also fixed.

  The piston 10 is fixed to the fixed conductor 14 described above, and the piston 10 and the puffer cylinder 9 are arranged in a slidable relationship. The puffer cylinder 9 is connected to an insulating operation rod 13 at the center thereof, and is configured to be driven by an operating device (not shown) while being guided by a piston 10. Further, the puffer cylinder 9 constitutes a compression device in which a gas space portion filled with an insulating arc-extinguishing gas called a puffer chamber 12 is formed by the piston 10, and the insulating arc-extinguishing property in the puffer chamber 12 during the shut-off operation. The gas is compressed and used for spraying and extinguishing as will be described later.

  FIG. 1 is an enlarged view of only the shut-off portion in the charged state described above. The fixed arc contact 5 is inserted into the insulating nozzle 11 and is in contact with the movable arc contact 7. The fixed main contact 6 is in contact with the movable main contact 8 at the outer periphery. The shut-off operation is performed by driving the insulating operation rod 13 to the right by an operating device (not shown). By this interruption operation, the movable main contact 8 is first separated from the fixed main contact 6, and then the movable arc contact 7 is separated from the fixed arc contact 5, and an arc is generated between the two. During the shut-off operation, the operation of the puffer cylinder 9 in the shut-off direction compresses the insulating arc-extinguishing gas in the puffer chamber 12 formed by the piston 10, and the compressed insulating arc-extinguishing gas is compressed into the insulating nozzle. 11, the arc is extinguished by spraying the arc generated by the separation between the movable arc contact 7 and the fixed arc contact 5 as shown in FIG.

FIG. 4 is a cross-sectional view showing the insulating nozzle 11 described above.
The insulating nozzle 11 is formed in a cylindrical shape having a throat portion 15 so that the insulating arc-extinguishing gas blowing gas compressed in the puffer chamber 12 acts on the arc between the movable arc contact 7 and the fixed arc contact 5. It has an inner surface which is a gas flow guiding portion for guiding the gas flow. Usually, the insulating nozzle 11 is entirely constituted by the same insulating material, but here, as the breaking operation progresses, the upstream portion 11a that is located upstream of the blowing gas flow and is first exposed to the arc. And the downstream portion 11b which is located downstream of the blowing gas flow and will be exposed to the arc thereafter. The upstream portion 11a is made of a resin material having a low ablation effect, while the downstream portion 11b is made of a low heat resin material having a higher ablation effect than the upstream portion 11a.

  The upstream portion 11a is made of an inorganic material that hardly absorbs arc energy, for example, a fluorine resin mixed with boron nitride (BN) powder. On the other hand, the downstream portion 11b is made of a black material that easily absorbs energy, for example, a fluororesin mixed with powdered molybdenum (MoS2) powder. Further, as the downstream portion 11b, a polyamide resin can be used instead of the fluororesin. However, when the insulating nozzle 11 is composed of two portions, the mechanical strength as a whole decreases if the resin as the base material is different. Therefore, it is desirable to use the same fluororesin as the base material resin. Moreover, the inorganic filler added in order to adjust an ablation effect can be used not only what was mentioned above.

  As described above, the insulating nozzle 11 is formed with the gas flow guide portion of the blowing gas from the upstream portion 11a and the downstream portion 11b of different resin materials, and the upstream portion 11a includes the throat portion 15 and upstream of the blowing gas flow. The gas flow guide part is located at When the arc is generated by moving the movable arc contact 7 from the fixed arc contact 5 in the insulating nozzle 11 during the interruption operation, first, the upstream portion 11a is exposed to the arc. Usually, the inner surface of the insulating nozzle 11 in this shut-off process is exposed to an ultra-high temperature arc reaching 20000 K, and a polyamide resin having low heat resistance is used for the resin constituting the insulating nozzle 11 by this arc energy. It is known that the ablation gas is generated by evaporating, and the gas pressure in the insulating nozzle 11 is further increased.

  However, the insulating nozzle 11 used here is composed of the upstream portion 11a made of a resin material having excellent heat resistance, and therefore the same portion until the fixed arc contact 5 comes out of the throat portion 15 of the insulating nozzle 11. Is exposed to the arc, the ablation effect is suppressed as compared with the case where the upstream portion 11a is made of a low thermal resin having the same high ablation effect as the downstream portion 11b. Therefore, in the initial stage of the shut-off operation, the pressure increase in the insulating nozzle 11 due to the ablation effect is reduced, and the reaction force against the operating device is also reduced. For this reason, the acceleration of the moving part of the blocking part at the initial stage of the blocking operation is increased as compared with the conventional case, and the speed is not reduced and the stagnation does not occur.

  Thereafter, immediately before the fixed arc contact 5 comes out of the throat portion 15 of the insulating nozzle 11, the internal pressure of the puffer chamber 12 peaks, and thereafter, the downstream portion 11b is exposed to the arc. When the fixed arc contactor 5 comes out of the throat portion 15, a sprayed gas flow is formed through the throat portion 15, but the downstream portion 11b is made of a low thermal resin having a high ablation effect. Increases rapidly, and this pressure increase is applied to effect effective spraying, and the arc quickly disappears.

The pressure transition in the insulating nozzle 11 during the above-described blocking operation will be further described with reference to FIG.
When the entire insulating nozzle 11 is made of the same insulating material as that of the downstream portion 11 b, the pressure in the insulating nozzle 11 changes as indicated by a pressure increase characteristic curve 17. This is because the ablation effect is increased and the pressure in the insulating nozzle 11 is increased before the fixed arc contact 5 comes out of the throat portion 15 of the insulating nozzle 11. The pressure in the insulating nozzle 11 is important for blowing the insulating arc-extinguishing gas necessary for interrupting the current to the arc. Decreasing the speed will reduce the breaking performance.

  On the other hand, when the entire insulating nozzle 11 is made of different insulating materials for the upstream portion 11 a and the downstream portion 11 b, the upstream side until the fixed arc contact 5 comes out of the throat portion 15 of the insulating nozzle 11. Since the ablation effect is suppressed by the portion 11a, the pressure in the insulating nozzle 11 is suppressed more than the conventional pressure increase characteristic curve 17 as can be seen from the pressure increase characteristic curve 18 in FIG. This means that the reaction force against the operating force at the beginning of the shut-off operation is reduced, and the acceleration of the moving part of the shut-off unit starts to increase from the initial stage of the shut-off operation. Can be suppressed. That is, when the same operating current is cut off with the same operating force, the breaking performance can be improved by the pressure increase characteristic curve 18.

  Thus, in the puffer-type gas circuit breaker according to the present invention, the upstream portion 11a made of an insulating material having a low ablation effect on the upstream side of the blowing gas flow, that is, a resin material having high heat resistance, and the upstream portion 11a. A gas flow guide portion is formed on the downstream side of the blowing gas flow by having an insulating material having a higher ablation effect than the upstream portion 11a, that is, a downstream portion 11b made of a resin material having relatively low heat resistance. Since the insulating nozzle 11 is used, the ablation effect is first suppressed in the upstream portion 11a exposed to the arc during the interruption operation, so that the reaction force is reduced and the acceleration of the movement of the interruption portion at the beginning of the interruption operation is increased. . On the other hand, although the ablation effect is added at the downstream portion 11b exposed to the arc at the end of the interruption operation, since the acceleration is sufficiently accelerated at this time, the interruption of the interruption operation due to the reaction force at the pressure peak is suppressed. The blocking performance can be improved by effective spraying.

  The boundary between the upstream portion 11a and the downstream portion 11b described above can be determined in consideration of the pressure increase due to the ablation effect, but includes the throat portion 15 of the insulating nozzle 11 and is located upstream of the blowing gas flow. The gas flow guide portion to be made is an upstream portion 11a made of a resin material having high heat resistance, and the gas flow guide portion located on the downstream side of the blowing gas flow from the throat portion 15 is made downstream of a resin material having low heat resistance. By setting it as the side part 11b, the timing which suppresses the ablation effect mentioned above and adds an ablation effect can be made desirable. In other words, the ablation effect is suppressed until the fixed arc contact 5 comes out of the throat portion 15 of the insulating nozzle 11, the reaction force is reduced, and the acceleration of the moving portion of the blocking portion at the beginning of the blocking operation is increased. However, when the stationary arc contact 5 comes out of the throat portion 15 of the insulating nozzle 11 and a blowing gas flow is formed from the throat portion 15, an ablation effect by the downstream portion 11 b is added, so that effective blowing is performed. Is called. Therefore, it is possible to perform effective gas blowing using the ablation effect while suppressing the speed reduction or stagnation at the initial stage of the shut-off operation.

  In the above-described embodiment, the cylindrical gas flow guide portion that includes the throat portion 15 and is located on the upstream side of the blowing gas flow from the throat portion 15 is the upstream portion 11b, and this is located inside the cylindrical downstream portion 11b. Although the insulating nozzle 11 is fixed and configured, it is not limited to this. In another embodiment, at least the inner surface side which becomes the gas flow guide portion of the insulating nozzle 11 is located in the upstream portion 11a, the downstream portion 11b, and the intermediate portion between them, and a heat resistant resin material intermediate between them. The same effect can be obtained even if it is configured to have an intermediate portion configured as described above. Further, when the range of the upstream portion 11b is defined, the entire gas flow guide portion on the upstream side of the blowing gas flow may be used as in the above-described embodiment, or the upstream portion 11b may be positioned upstream of the blowing gas flow. You may limit to the gas flow guide part exposed to an arc except the gas flow guide part which is not exposed to an arc. In any case, of the gas flow guide portion of the insulating nozzle 11, the portion defined as the upstream portion 11a located upstream of the blowing gas flow is defined as the downstream portion 11b located downstream of the blowing gas flow. What is necessary is just to manufacture with the resin material whose ablation effect and heat resistance are inferior to the defined part.

  The puffer type gas circuit breaker according to the present invention is not limited to the configuration shown in FIG. 3 and can be applied to other configurations.

DESCRIPTION OF SYMBOLS 1 Metal tank 2, 3 Center conductor 4 Cylindrical conductor 5 Fixed side arc contact 6 Fixed main contact 7 Moving arc contact 8 Movable main contact 9 Puffer cylinder 10 Piston 11 Insulation nozzle 11a Upstream part 11b Downstream part 12 Puffer chamber 15 Throat part 17, 18 Pressure rise characteristic curve

Claims (1)

A fixed arc contact and a movable arc contact arranged in a sealed tank filled with an insulating arc-extinguishing gas so as to be able to contact and separate, a compression device for compressing the insulating arc-extinguishing gas during a shut-off operation, and the fixed arc contact Insulating arc-extinguishing gas provided by surrounding the contact portion of the movable arc contact and compressed by the compression device is sprayed on the arc generated by the separation between the fixed arc contact and the movable arc contact In a puffer type gas circuit breaker with an insulating nozzle to guide,
The insulating nozzle includes an throat portion having an elongated hole shape and has an upstream portion located on the upstream side of the blowing gas and a downstream portion located on the downstream side of the blowing gas excluding the throat portion. The upstream portion is formed of a resin material having a low ablation effect made of a fluororesin mixed with boron nitride powder, and the downstream portion is made of the upstream portion made of a fluororesin mixed with molybdenum disulfide powder. A puffer-type gas circuit breaker made of a resin material with high ablation effect.

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