JP4421331B2 - Gas circuit breaker - Google Patents

Description

  The present invention is configured such that arc extinguishing gas is blown to the arc generated between the contacts when the current is interrupted to extinguish the arc, and the hot gas generated by arc extinguishing is guided in a direction away from both contacts. The present invention relates to a gas circuit breaker, and more particularly, to a gas circuit breaker having an improved configuration in order to improve the dielectric strength of a flow path portion through which hot gas flows.

As a circuit breaker that performs current switching in a power system, an arc-extinguishing medium is filled in a sealed container made of grounded metal or insulator, and the arc-extinguishing medium is sprayed on the arc generated between the contacts when the current is interrupted. A type that extinguishes the arc and cuts off the current is widely used. Among them, a puffer type SF ₆ gas circuit breaker that sprays on an arc by using SF ₆ gas as an arc extinguishing medium and mechanically compressing SF ₆ gas with a piston at the time of current switching is the mainstream.

In addition to SF ₆ gas, an air circuit breaker using air as an arc extinguishing medium, or various gas circuit breakers using some alternative gas instead of SF ₆ gas having a high global warming effect has been proposed. . In this specification, all circuit breakers that use SF ₆ gas, air, or other various arc-extinguishing gases as arc extinguishing media are collectively referred to as gas circuit breakers.

FIG. 13 is an example of a cross-sectional structure diagram of such a gas circuit breaker, and shows a state during the breaking operation. Each part in FIG. 13 is basically a coaxial cylindrical shape. As shown in FIG. 13, the tank 1 which is a grounded metal container is filled with an arc extinguishing gas 2 such as SF ₆ gas. Further, in the tank 1, a movable contact portion 10 that operates in the axial direction with respect to the tank 1 and a fixed contact portion 20 that is fixed at a fixed position with respect to the tank 1 are disposed to face each other.

  The movable contact portion 10 and the fixed contact portion 20 are respectively provided with a cylindrical movable arc contact 11 and a rod-shaped fixed arc contact 21 inserted into a hollow portion in the movable arc contact 11. Both arc contacts 11 and 21 are in a contact conduction state during normal operation, and are separated by relative movement during a shut-off operation, and an arc 3 is generated in the space between both contacts 11 and 21.

  Further, on the movable contact portion 10 side, as a gas flow generating means for blowing the arc extinguishing gas 2 to the arc 3 as a gas flow, with respect to the piston 12 fixed to a fixed position with respect to the tank 1 and the piston 12 A relatively moving cylinder 13, a puffer chamber 14 formed inside the cylinder 13 by the piston 12, an insulating nozzle 15 fixed to the tip of the cylinder 13 and surrounding the movable arc contact 11, and the like are provided.

  Further, on the movable contact portion 10 side and the fixed contact portion 20 side, a hot gas for inducing a hot gas generated by spraying the arc extinguishing gas 2 onto the arc 3 in a direction away from the arc contacts 11 and 21. As guide means, a metal hollow rod 16 and a metal exhaust tube 22 are provided. Here, the metal exhaust tube 22 is a cylindrical member installed behind the fixed arc contact 21, and a fixed-side hot gas flow 30 a flowing from the arc 3 to the fixed contact portion 20 side is disposed inside the metal exhaust tube 22. A hot gas flow path through which the gas passes is formed. The metal hollow rod 16 is a cylindrical member that is linearly continuous with the movable arc contact 11 in the axial direction, and the movable hollow contact 16 has a movable side that flows from the arc 3 to the movable contact portion 10 side. A hot gas flow path is formed through which the hot gas flow 30b passes.

  The shut-off operation of the gas circuit breaker having the above configuration is as follows. First, when the movable contact portion 10 moves in the left direction in the figure, which is a direction away from the fixed contact portion 20, the piston 12 fixed to the tank 1 compresses the puffer chamber 14, which is the internal space of the cylinder 13. The pressure in the chamber 14 is increased. As a result, the arc-extinguishing gas 2 existing in the puffer chamber 14 is guided to the insulating nozzle 15 as a high-pressure gas flow, and blows strongly against the arc 3 generated between the arc contacts 11 and 21. Attached. As a result, the conductive arc 3 generated between the arc contacts 11 and 21 disappears and the current is interrupted.

  At the time of such current interruption, the arc extinguishing gas 2 blown to the high-temperature arc 3 becomes a high-temperature and low-density hot gas, and both the hot gas flow 30a on the fixed side and the hot gas flow 30b on the movable side are both It is discharged away from the space between the arc contacts 11, 21. The fixed-side hot gas flow 30a is guided into the exhaust cylinder 22, cooled to some extent inside the exhaust cylinder 22, and then discharged from the end portion 23 of the exhaust cylinder 22 into the free space in the tank 1 outside the fixed contact portion 20. . In this case, the exhaust tube 22 and the tank 1 constitute a hot gas induction system that induces and cools the fixed-side hot gas flow 30a to prevent a decrease in the dielectric strength on the fixed contact portion 20 side.

  The movable-side hot gas flow 30b is guided to the hollow rod 16 provided continuously with the movable arc contactor 11, and then passes through several exhaust holes provided in the piston 12, the cylinder 13, and the like. Finally, it is discharged into the free space in the tank 1 outside the movable contact portion 10. In this case, the hollow rod 16 and the tank 1 constitute a hot gas induction system that induces and cools the movable-side hot gas flow 30b to prevent a decrease in the dielectric strength on the movable contact portion 10 side.

  The fixed-side hot gas flow 30a passing through the exhaust tube 22 is in the same direction as the gas flow blown to the arc 3, so that the movable hot gas flow in the opposite direction to the gas flow blown to the arc 3 is used. The flow rate is larger than 30b, and the amount of heat is also large. For this reason, it is necessary to cool the hot gas flow 30 a on the fixed side more actively than on the movable side, and as a result, the diameter of the exhaust tube 22 is significantly larger than that of the hollow rod 16.

  By the way, the gas circuit breakers as described above tend to be downsized for the purpose of space saving and cost reduction in recent years. On the other hand, reducing the material used for the circuit breaker has a great effect on the reduction of the global environmental load, and there is a strong social demand for a compact gas circuit breaker from the viewpoint of environmental protection. Under such circumstances, the gas circuit breaker is being made more compact, and accordingly, the size of the tank 1 and the exhaust pipe 22 tends to be further reduced.

  However, when the exhaust cylinder 22 is simply reduced in size, the volume for cooling the fixed-side hot gas flow 30a generated between the arc contacts 11 and 21 is inevitably reduced. The time until the hot gas flow 30a on the fixed side reaches the end portion 23 of the exhaust pipe 22, that is, the time spent for cooling the hot gas flow 30a inside the exhaust pipe 22 is also shortened. For this reason, the hot gas flow 30a discharged from the end portion 23 of the exhaust tube 22 is easily maintained in a high temperature state for a long time.

  On the other hand, since the transient recovery voltage generated by the transient phenomenon of the power system circuit is applied to the exhaust cylinder 22 after the current interruption, the exhaust cylinder 22 becomes a high potential, but when the tank 1 is downsized, the ground potential is Since the distance between a certain tank 1 and the exhaust pipe 22 is inevitably small, the electric field strength at the end portion 23 of the exhaust pipe 22 tends to be higher.

  To summarize the above points, when the conventional gas circuit breaker is downsized, the electric field strength at the end portion 23 of the exhaust tube 22 is increased after the current is interrupted, and the temperature of the discharged hot gas flow 30a is also increased. Easy to hold. Here, in general, when the pressure is constant, the higher the electric field, the easier the dielectric breakdown occurs, and the higher the gas temperature, the easier the dielectric breakdown occurs. That is, when the gas circuit breaker is further reduced in size, the dielectric strength of the end portion 23 of the exhaust pipe 22 decreases, and an insulation breakdown accident occurs between the end portion 23 and the tank 1 (hereinafter, this phenomenon is referred to as “ground fault”). ")" Is likely to occur.

  In the above description, the decrease in the dielectric strength on the fixed contact portion 20 side when the gas circuit breaker is downsized has been described. However, the phenomenon of such a decrease in the dielectric strength is also the same on the movable contact portion 10 side. This is a phenomenon that occurs. That is, if the gas circuit breaker is further reduced in size, the dielectric strength between the hot gas exhaust section provided in the movable contact portion 10 and the tank 1 is likely to decrease for the same reason. Is likely to occur.

Further, as described above, a gas circuit breaker in which some alternative gas is applied as an arc extinguishing medium instead of SF ₆ gas having a high global warming effect has been proposed recently. It is known that it is lower than SF ₆ gas (for example, see Non-Patent Document 1). Therefore, when an alternative gas circuit breaker that is environmentally friendly is constructed, it becomes more difficult to avoid the above-mentioned decrease in dielectric strength and the occurrence of ground faults resulting from it, resulting in an increase in size of the tank. There is a concern that it will be mixed.

  In FIG. 13, a gas circuit breaker using a grounded metal container has been described as an example. However, there is a gas circuit breaker sealed with an insulator such as an insulator. In such a gas circuit breaker, grounding to the ground tank does not occur, but if the insulator and its associated parts are exposed to a very high temperature gas flow that is generated when a large current is interrupted, it will be altered. There was a problem such as melting, and it was necessary to cool the hot gas quickly.

  In FIG. 13, as the most general gas circuit breaker, one of the contact portions is fixed, and the prior art has been described by taking an example in which one of the contact portions is driven. A relative-drive type gas circuit breaker has also been proposed. Even in such a gas circuit breaker, there are exactly the same problems as described above, such as a decrease in dielectric strength and the occurrence of a ground fault phenomenon resulting therefrom.

  Conventionally, as one method for solving the above problems, it has been proposed to form irregularities on the inner peripheral surface of the exhaust tube 22 (see Patent Document 1). FIG. 14 and FIG. 15 show the configuration of such an exhaust cylinder 22. FIG. 14 shows an example in which ring-shaped pleats 41 are continuously formed as irregularities, and FIG. 15 shows an example in which spiral grooves 42 are formed. In Patent Document 1, by adopting such a configuration, when the hot gas flows inside the exhaust tube 22 having the unevenness, a gas having a high density and a large viscosity intensively entangles with the unevenness on the inner peripheral surface. A gas having a high density, that is, a gas having a high dielectric strength, flows in the vicinity of the inner peripheral surface of the exhaust tube 22, and an effect is described in which a reduction in the dielectric strength of this portion can be prevented.

JP-A-8-124464 IEEJ Technical Report No. 841, "Global Environmental Load of SF6 and SF6 Mixing / Alternative Gas Insulation" May 25, 2001

  By the way, the action described in Patent Document 1 is merely based on a very qualitative interpretation of the influence of the uneven surface of the gas flow path on the gas flow. In this Patent Document 1, the specific configuration such as the specific arrangement and size of the unevenness and the relationship with the size and shape of the exhaust tube 22 is unclear. Therefore, any specific configuration is sufficient. It is not described whether the effect can be obtained. That is, by simply providing irregularities on the inner peripheral surface of the exhaust tube 22, it is possible to sufficiently prevent a decrease in the dielectric strength of this portion by flowing only a gas having a high dielectric strength near the inner peripheral surface of the exhaust tube 22. Have difficulty.

  Further, in Patent Document 1, although it is mentioned that the exhaust tube 22 is a high electric field portion, only the temperature and density of the hot gas flow flowing around the exhaust tube 22 are considered. Since no consideration is given to the specific electric field configuration around the exhaust tube 22, it is difficult to sufficiently prevent a decrease in the dielectric strength also from this point. That is, the dielectric strength is determined by the temperature and density of the hot gas and the electric field strength of the portion through which the hot gas flows. For example, when considering the conditions of the same pressure and applied voltage, the case where a gas having a low temperature is present in a portion having a high electric field strength is greater than a case where a gas having a high temperature is present in a portion having a low electric field strength. On the contrary, the dielectric strength can be low. In other words, for the purpose of improving the dielectric strength of the entire hot gas induction system consisting of the exhaust tube 22 and the sealed container, it is not sufficient to consider only the temperature and density of the hot gas flow, and the electric field configuration must also be considered. There is. Therefore, also from this point, the technique described in Patent Document 1 cannot always improve the dielectric strength.

  Further, in the technique described in Patent Document 1, since no consideration is given to the hot gas flow flowing on the movable contact portion 10 side shown in FIG. 13, it is possible to prevent a decrease in dielectric strength on the movable contact portion 10 side. It ’s not good.

  The present invention has been proposed in order to solve the above-described problems of the prior art, and its purpose is based on the understanding of the detailed cooling mechanism and the periphery of the exhaust tube and hollow rod for inducing hot gas. In addition to the temperature and density of the flowing hot gas flow, taking into account the electric field configuration, a specific configuration that can effectively improve the dielectric strength of the entire hot gas induction system by effectively cooling the hot gas flow It is to clarify and thereby provide a small but reliable gas circuit breaker.

  In order to achieve the above object, the present invention provides a cylindrical member by providing at least four or more rows of grooves extending in the direction intersecting the traveling direction of the hot gas on the inner surface of the cylindrical member for guiding the hot gas. In addition to the temperature and density of the hot gas flow that flows around the shaped member, the electric field configuration is also taken into account, and the hot gas flow can be effectively cooled to effectively improve the dielectric strength of the entire hot gas induction system It is a thing.

  The present invention first relates to a gas circuit breaker having a certain basic configuration. The basic configuration of this gas circuit breaker is as follows. First, the arc-extinguishing gas is filled in a sealed container, and the first contact portion and the second contact portion are arranged to face each other. Here, the first contact portion and the second contact portion are provided with a first arc contact and a second arc contact, respectively, and both the contacts are in a contact conduction state during normal operation, and are relatively moved during a shut-off operation. An arc is generated in the space between the two contacts while being separated. Moreover, the gas flow generation means which blows off arc-extinguishing gas with respect to an arc is provided in the 1st contact part. Furthermore, a hot gas induction means for guiding the hot gas generated by spraying the arc extinguishing gas to the arc by the gas flow generating means on the first contact portion and the second contact portion in a direction away from both the contacts. Each is provided.

The present invention has the following characteristics in the gas circuit breaker having such a basic configuration. That is, the hot gas guiding means of the second contact portion is a metal exhaust tube, and the exhaust tube is configured such that the hot gas discharged from the arc is discharged into the container from the front in the traveling direction. The inner surface of the exhaust pipe is provided with at least four or more rows of grooves extending in a direction intersecting the traveling direction of the hot gas and continuously arranged in the traveling direction of the hot gas , The exhaust cylinder includes a terminal opening type inner cylinder and an outer cylinder arranged to cover the terminal opening surface of the inner cylinder and the outer peripheral surface in the vicinity of the terminal portion, and the hot gas is formed inside the inner cylinder. The inner cylinder and the outer cylinder are formed so as to pass through the inner channel and the outer channel formed between the inner cylinder and the outer cylinder. Each channel wall surface of the cylinder is provided with at least four rows of grooves. It has been.

According to the present invention, the gas temperature can be greatly reduced in the vicinity of the end portion of the exhaust stack having a relatively high electric field strength and a high possibility of being directly exposed to a high-temperature hot gas flow. Therefore, the dielectric strength of the part can be improved. Thus, in addition to the temperature and density of the hot gas stream flowing in the periphery of the stack, in terms of even field configuration of stack considering, effectively cooling the hot gas by inducing hot gas stream from these two viewpoints The dielectric strength of the entire system can be improved efficiently.

  As described above, according to the present invention, based on the understanding of the detailed cooling mechanism, in addition to the temperature and density of the hot gas flow flowing around the exhaust pipe and the hollow rod, the hot gas gas is also considered. A specific configuration that can effectively improve the dielectric strength of the entire hot gas induction system by effectively cooling the flow is `` the direction of the hot gas on the inner surface of the exhaust tube or hollow rod that induces the hot gas. It is clear that “at least four rows of grooves extending in the intersecting direction are provided”. According to the present invention, such a specific configuration can provide a gas circuit breaker that is small but highly reliable.

  Hereinafter, embodiments of a gas circuit breaker to which the present invention is applied will be described in detail with reference to FIGS. Note that, from the viewpoint of simplifying the description, the same reference numerals are given to the same parts as those of the conventional technology described above.

[1. First Embodiment]
[1-1. Constitution]
FIG. 1 is a schematic cross-sectional view showing the periphery of an exhaust pipe of a gas circuit breaker according to a first embodiment of the present invention. Among the general gas circuit breakers shown in FIG. Only the vicinity of the end portion 101 of the exhaust tube 100 of the contact portion 20 is shown enlarged. FIG. 1 shows a state at the time of current interruption, and more specifically shows a state in which a hot gas flow 30a flows through the exhaust pipe 100 and is discharged from the end portion 101 to the free space in the tank 1. Yes.

  According to the present invention, at least four or more rows of grooves 110 extending in the direction intersecting the flow direction (traveling direction) of the hot gas flow 30a are continuously arranged in the flow direction on the inner surface of the exhaust pipe 100. ing. Although the shape of the groove 110 is not necessarily uniform, FIG. 1 shows a state in which the groove 110 having a pitch P and a depth H and having an isosceles cross section is uniformly formed. In FIG. 1, from the viewpoint of simplifying the drawing, ring-shaped grooves 110 extending in a direction substantially perpendicular to the flow direction of the hot gas flow 30 a are continuously formed in the flow direction so that adjacent grooves are in contact with each other. A state is shown in which the entire plurality of rows of grooves 110 are formed in a “jagged shape”.

  In addition, the shape of the groove 110 is not necessarily a ring shape, and the groove 110 is formed in a spiral shape and arranged so that the turns (rows) are close to each other, or a part of those shapes or any combination thereof. Etc. are also conceivable. That is, in the configuration of the exhaust pipe 100 according to the present invention, an essential point is that at least four rows or more of the grooves 110 extending in the direction intersecting the flow direction of the hot gas flow are formed. About a point, it can change suitably.

In the exhaust tube 100 shown in FIG. 1, when the groove pitch P is further equal to or more than 1/4 of the groove depth H, that is, expressed by an equation:
P ≧ H / 4
It is formed to become.

Furthermore, when the range in which the groove 110 can be provided in the flow direction of the hot gas flow is C, the distance L between the groove range C and the end portion 101 of the exhaust tube 100 is 5 of the inner diameter D of the exhaust tube 100. % Or more, that is, when described by an expression,
L ≧ 0.05 ・ D
It is formed to become.

  Further, the cross-sectional shape of the partition wall tip 111 that separates the rows of the grooves 110 is restricted by a processing method or the like, but is formed as sharply as possible. In general, when forming by casting, it is difficult to form sharply, but even in that case, the cross section of the partition wall tip 111 is formed so that the radius is 5 mm or less.

[1-2. Action]
Hereinafter, the operation of the gas circuit breaker of the present embodiment having the above-described configuration will be described based on the results of simulation by numerical analysis and verification experiments using an actual gas circuit breaker.

[1-2-1. Basic action]
FIG. 2 is an analysis graph showing an example of an analysis result when a gas flow analysis is performed in a two-dimensional rotationally symmetric shape as a numerical analysis of the gas circuit breaker shown in FIG. FIG. 2 shows the analysis results when the arc extinguishing gas: SF ₆ gas, breaking current: AC 50,000 A, and arc firing period: 24 ms as analysis conditions. It shows the state of the moment when the arc disappears. The lower side of FIG. 2 is the rotation axis in the analysis, and FIG. 2 corresponds to the upper half of FIG. The model of the exhaust tube 100 in the analysis is such that the number of grooves: 4 rows or more, the groove pitch P: 1/4 or more of the groove depth H.

  From FIG. 2, the hot gas flow is disturbed by four or more rows of grooves 110 provided on the inner surface of the exhaust tube 100, and the normal temperature gas and the hot gas flow inside the groove 110 are mixed, and the vicinity of the surface of the exhaust tube 100 is centered. It can be seen that the hot gas flow is gradually cooled. In particular, in the vicinity of the end portion 101 of the exhaust stack 100 where the electric field strength is relatively high and the possibility of direct exposure to a high-temperature hot gas flow is high, the gas temperature is greatly reduced.

  In the case of a simple cylindrical exhaust cylinder 22 as shown in FIG. 13 that has been widely employed in the past, the end portion 23 of the exhaust cylinder 22 is likely to be directly exposed to a high-temperature hot gas flow, so that dielectric breakdown may occur. However, according to the exhaust pipe 100 of the present embodiment in which four or more rows of grooves 110 as shown in FIG. 1 are provided, the hot gas flow in the vicinity of the terminal portion 101 of the exhaust pipe 100 can be effectively cooled. Therefore, the dielectric strength of this part can be greatly improved.

  In addition, as can be seen from the analysis graph of FIG. 2, the hot gas at the central portion of the exhaust stack 100 away from the groove 110 is still easily maintained at a high temperature compared to the vicinity of the surface where the groove 110 is provided. However, the electric field strength is particularly high mainly in the vicinity of the surface of the exhaust stack 100, and the electric field strength in the central portion of the exhaust stack 100 is smaller than that in the vicinity of the surface of the exhaust stack 100. By restoring the dielectric strength, the dielectric strength of the entire hot gas induction system including the exhaust stack can be significantly restored.

FIG. 3 is an actual measurement graph showing an example of an actual measurement result when the dielectric strength at the end portion of the exhaust stack is actually measured using a metal tank type SF ₆ gas circuit breaker for an ultrahigh pressure system. In this FIG. 3, in order from the left, in a gas circuit breaker that employs a dielectric strength of “normally” (when no current is interrupted, that is, when there is no hot gas flow), “a grooved exhaust tube” ( Dielectric strength in the case of current interruption and when there is a hot gas flow, and for comparison, in a gas circuit breaker that employs a conventional “simple cylindrical exhaust” (there is a hot gas flow) ) Shows the measurement results of the dielectric strength.

  In FIG. 3, an exhaust stack 100 shown as “a grooved exhaust stack” includes a groove number: 4 rows or more, a groove pitch P: a groove depth H of 1/4 or more, and a distance between the groove range and the exhaust tube end portion. L: It is comprised so that it may become 5% or more of the exhaust pipe internal diameter D. FIG. However, the groove was formed in a spiral shape. Further, it is assumed that the interruption current is 50,000 A AC and the arc ignition time is 24 ms, and in all cases, almost the same hot gas flow flows into the exhaust stack. In FIG. 3, the dielectric strength of “normal” (when no hot gas flow is present) is assumed to be 100%, and each value is shown as a relative value.

  From FIG. 3, the dielectric strength is reduced due to the presence of the hot gas flow when the current is interrupted. However, in the simple cylindrical exhaust cylinder 22, it is significantly reduced to about 1% when the current is not interrupted. On the other hand, when the exhaust tube 100 with four or more rows of grooves according to the present invention shown in FIG. 1 is adopted, it can be seen that the reduction is only 25%. That is, it can be seen that the use of the exhaust stack 100 shown in FIG. 1 improves the dielectric strength at the time of current interruption to 25 times the conventional one.

  The specific numerical values shown in FIGS. 2 and 3 are expected to vary depending on various conditions such as the shape of the tester, the cut-off current, and the arc extinguishing gas. By using the exhaust cylinder 100 provided with four or more rows of grooves 110 as shown in FIG. 4, the dielectric strength of the gas circuit breaker at the time of current interruption is compared with the case where the conventional simple cylindrical exhaust cylinder 22 is used. It is clear that can be greatly improved.

  The actions clarified above are summarized as follows. That is, in the exhaust pipe 100 provided with four or more rows of grooves 110 as shown in FIG. 1, when the hot gas flow 30a flows through the exhaust pipe 100, the hot gas flow protrudes into the flow path. It is disturbed by. Since normal temperature gas in the groove 110 exists in the immediate vicinity of the hot gas flow near the surface of the exhaust tube 100 subjected to the disturbance, both are vigorously mixed.

  Thereby, the hot gas flow is effectively cooled around the surface of the exhaust pipe 100 provided with the groove 110, and the dielectric strength is recovered. Compared to the vicinity of the surface of the exhaust tube 100, the hot gas in the central portion of the exhaust tube 100 is still easily maintained at a high temperature. However, the electric field strength is particularly high mainly in the vicinity of the surface of the exhaust stack 100, and the electric field strength in the central portion of the exhaust stack 100 is smaller than that in the vicinity of the surface of the exhaust stack 100. By restoring the dielectric strength, the dielectric strength of the entire hot gas induction system can be significantly restored.

  By the way, in FIG. 2, it turns out that the hot gas near the exhaust pipe 100 surface is gradually cooled according to the flow. This is very different from the image of cooling uniformly along the flow as in the conventional gas flow shown in FIG. 14, and in order to obtain a significant cooling effect, the surface of the exhaust stack 100 This suggests that the number (number of rows) of grooves 100 applied to is extremely important.

[1-2-2. Effect by number of grooves]
FIG. 4 is an analysis graph showing the relationship with the hot gas temperature when the number of grooves is changed along the hot gas flow path on the surface of the exhaust tube 100 of FIG. In FIG. 4, the vertical axis represents the gas temperature on the surface of the exhaust tube 100, and the horizontal axis represents the number of groove rows along the gas flow path. FIG. 4 shows that the hot gas temperature on the surface of the exhaust tube 100 decreases as the number of rows of the grooves 110 increases along the hot gas flow path.

  In this case, the number of rows of the grooves 110 provided in the exhaust pipe 100 can be considered as “the number of opportunities for generating a disturbance” for mixing the high-temperature hot gas flow and the room temperature gas in the groove 110 part. As apparent from FIG. 4, in order to cool the hot gas flow, it is preferable that the number N of grooves provided on the inner surface of the exhaust tube 100 is larger. However, since the size of the exhaust stack 100 is actually limited, it is impossible to increase the number N of groove rows without limit. On the other hand, it can be determined from FIG. 4 that a significant hot gas cooling effect can be obtained by forming at least four rows of grooves.

[1-2-3. Effect by dimensional relation of groove section]
As described above, since the size of the exhaust stack 100 is practically limited, not only the number of grooves N but also the range in which the grooves can be provided is practically limited. Therefore, if the range C in which the groove 100 shown in FIG. 1 can be provided is considered to be constant, P · N = C between the groove pitch P and the number N of groove rows.
There is a relationship.

  That is, when the range C in which the grooves can be provided is constant, a case where the groove pitch P is reduced to increase the number N of groove rows, and a case where the groove pitch P is increased to reduce the number N of groove rows N There are two possible directions. As described above, the number N of grooves can be considered as the “number of opportunities for generating a disturbance” for mixing the hot gas flow 30a and the room temperature gas in the groove 110 part. The more it is, the better.

  Here, when the range C in which the grooves can be provided is constant, the groove pitch P is inevitably reduced as the number N of grooves is increased, as is apparent from the above formula. When the groove pitch P becomes smaller than the groove depth H, the groove cross-sectional shape becomes a sharper shape as shown in FIG. In FIG. 5, the relationship between the groove pitch P and the groove depth H is P = 2H, P = H, P = H / 2, P = H / 3, and P = H / 4. It is explanatory drawing which shows a groove cross-sectional shape.

  As is apparent from the cooling mechanism of the hot gas flow described above, if the groove cross-sectional shape becomes sharp, the room temperature gas at the back of the groove becomes difficult to act on the hot gas flow flowing on the groove surface, which is effective. Cooling of the hot gas flow becomes difficult. However, as shown in FIG. 5, if the groove pitch P is secured at least 1/4 or more with respect to the groove depth H, the room temperature gas inside the groove can be effectively used for cooling the hot gas flow 11a. A significant hot gas flow cooling effect can be obtained. The number N of grooves and the groove pitch P should be selected to be optimal values under various use conditions. In general, in order to obtain a significant cooling effect of the hot gas flow, at least as described above, It is necessary to ensure that the number N of grooves is 4 or more and the groove pitch P is 1/4 or more of the groove depth H.

[1-2-4. Action by dimensional relationship with groove at end of exhaust stack]
By the way, when the groove 110 is provided on the inner surface of the exhaust tube 100 as in this embodiment, the electric field strength of the terminal portion 101 of the exhaust tube 100 may be higher than that of the conventional simple cylindrical exhaust tube 22. There is. As described above, since the dielectric strength of the portion exposed to the hot gas under the same pressure is determined by the temperature of the hot gas and the electric field strength of the portion, the groove 110 is provided in the exhaust tube 100. Even if the hot gas temperature is lowered by this, if the electric field strength is increased by providing the groove 110, the dielectric strength may be lowered. Therefore, in order to improve the dielectric strength, it is necessary to sufficiently consider not only the cooling property of the hot gas flow but also the electric field configuration when the groove 110 is provided.

FIG. 6 is an analysis graph showing an example of an analysis result obtained by an electric field analysis of a change in electric field strength in accordance with a dimensional relationship with the groove at the end portion of the exhaust stack. In FIG. 6, the ratio L / D (%) between the distance L from the end portion 101 of the exhaust tube 100 to the range C where the groove 110 is provided and the tube inner diameter D of the exhaust tube 100 is shown on the horizontal axis. On the vertical axis, the ratio of the electric field intensity E at the end portion 101 of the exhaust stack 100 when the groove 110 is provided to the electric field intensity E ₀ of the same portion when the groove 110 is not provided is taken.

  As can be seen from FIG. 6, by providing the groove 110 on the inner surface of the exhaust tube 100, the electric field strength of the end portion 110 of the exhaust tube 100 increases, but by increasing the ratio of the distance L to the tube inner diameter D, An increase in electric field strength can be suppressed. The curve shown in FIG. 6 varies depending on the specific value of the cylinder inner diameter D, the positional relationship with the tank 1, and the like. However, from FIG. It can be determined that an increase in electric field strength at the end portion 101 of the cylinder 100 can be avoided.

[1-2-5. Summary of action]
The above actions are summarized as follows. First, at least four or more rows of grooves 110 extending in the direction intersecting the flow direction of the hot gas flow 30a are provided on the inner surface of the exhaust pipe 100 so as to be continuously arranged in the flow direction, and the groove pitch P is set to the groove depth. By setting the length H to at least 1/4 or more, the hot gas flow can be effectively cooled. Further, by setting the distance L between the end portion 101 of the exhaust tube 100 and the range C where the groove is provided to be 5% or more of the exhaust tube inner diameter D, the exhaust tube 100 by providing the groove on the inner surface of the exhaust tube 100. An increase in electric field strength at the terminal portion 101 can be suppressed. Therefore, by using the exhaust pipe 100 with such a groove 110, the dielectric strength of the gas circuit breaker at the time of current interruption can be greatly improved without requiring any other special device.

  In addition, as described above, it is very important to generate a disturbance in the hot gas flow at the partition wall tip 111 that separates the rows of the grooves 110 in order to obtain the effect of the present invention. In order to more effectively disturb the hot gas flow, the shape of the partition wall tip 111 protruding into the flow path of the hot gas flow is not a smooth arc shape as shown in FIGS. It needs to be as sharp as possible. The shape of the partition tip 111 depends on the processing method. For example, when the groove 110 is formed by casting, it is generally difficult to sharply form the tip between the grooves. However, it is desirable to make the cross-sectional radius of the tip between the grooves as small as possible. Specifically, if the cross section of the partition wall tip 111 is formed to have a radius of 5 mm or less, it is possible to avoid greatly impairing the cooling effect of the hot gas flow.

[1-3. effect]
As described above, according to the first embodiment, it is only necessary to provide at least four or more rows of grooves that intersect the flow direction of the hot gas flow in the exhaust pipe, and no other special device is required. The hot gas generated at the time of interruption can be cooled effectively. In particular, the gas temperature can be greatly reduced near the end of the exhaust stack where the electric field strength is relatively high and the possibility of direct exposure to a high-temperature hot gas flow is high. The dielectric strength of can be improved. Therefore, in addition to the temperature and density of the hot gas flow flowing around the exhaust pipe, the electric field configuration of the exhaust pipe is also taken into account, and the hot gas flow is effectively cooled and fixed contact is made from these two viewpoints. Since the dielectric strength of the entire hot gas induction system in the section can be efficiently improved, a small and highly reliable gas circuit breaker can be provided.

[1-4. Modification of groove shape]
In the first embodiment, the case where the exhaust pipe 100 is provided with the groove 110 having a uniform isosceles triangle in cross section has been described. However, the specific shape of the groove can be freely selected. . FIG. 7 to FIG. 9 are schematic cross-sectional views respectively showing modifications with different groove shapes.

  Here, the cross-sectional shape of the groove 710 shown in FIG. 7 is a triangle having two different lengths, and the partition wall tip 711 separating the rows is directed in an oblique direction facing the hot gas flow 30a. Moreover, the cross-sectional shape of the groove | channel 810 shown in FIG. 8 is U shape, and the whole groove | channel 810 is formed in a spiral shape and is arrange | positioned so that turns (rows) may adjoin. Moreover, the cross-sectional shape of the groove | channel 910 shown in FIG. 9 is a parallelogram, and the partition front-end | tip part 911 which divides between rows has faced the diagonal direction which opposes the hot gas flow 30a.

  As in the first embodiment, in any of the modifications shown in FIGS. 7 to 9, the groove intersects the flow direction of the hot gas flow in order to perform effective hot gas flow cooling. At least 4 rows or more are formed so as to extend in the direction, and the groove pitch P is configured to be at least 1/4 or more of the groove depth H.

  In each of the modifications shown in FIGS. 7 to 9 as well, it is possible to obtain the same operational effects as those of the first embodiment.

[2. Second Embodiment]
FIG. 10 is a schematic cross-sectional view showing the periphery of the exhaust tube of the gas circuit breaker according to the second embodiment of the present invention, and the surface of the groove 110 of the exhaust tube 100 in the first embodiment is colored gray or black. The layer 1001 is added. Specific coloring methods include physical coating with paint or the like, or various chemical surface treatments such as phosphate film treatment in the case of iron. Note that at least four or more rows of grooves 110 extending in the direction intersecting the flow direction of the hot gas flow 30a are provided on the inner surface of the exhaust pipe 100, and the groove pitch P is at least 1/4 of the groove depth H. Other configurations such as the above are the same as those in the first embodiment.

  According to the second embodiment having the above-described configuration, in addition to the same operation as that of the first embodiment, the addition of the gray or black colored layer 1001 to the surface of the groove 110 further increases the heat. Energy loss due to radiation from the gas flow is increased, and the action of cooling the hot gas flow more effectively can be obtained. Below, this effect | action is demonstrated in detail.

  First, the hot gas flow when a large current is interrupted becomes very high, reaching several thousand K. In this case, energy is also emitted from the hot gas in the form of radiation. In the case of the conventional simple cylindrical exhaust cylinder 22 as shown in FIG. 13, most of the radiant energy that has reached the inner wall surface of the exhaust cylinder is reflected by the wall surface and returned to the hot gas flow again. For this reason, there is little energy loss by the radiation from a hot gas flow.

  The exhaust tube 100 according to the present invention is characterized in that a groove is formed on the inner surface, but radiation light incident on the groove portion is repeatedly reflected at the same portion, and finally easily absorbed into the groove portion. Further, because the surface area of the inner surface of the exhaust tube is increased by providing the groove, the exhaust tube in the present invention has essentially higher radiation energy absorption efficiency than the conventional simple cylindrical exhaust tube. In addition, in this embodiment, since the inner surface of the exhaust stack 100 is colored gray or black by the colored layer 1001, the absorption efficiency of the radiant energy can be further remarkably increased. For this reason, the energy loss due to radiation from the hot gas flow is increased, and the hot gas flow is more significantly cooled.

  Therefore, according to the second embodiment, in addition to the effects of the first embodiment, the colored layer 1001 provided on the surface of the groove 110 further increases the energy loss due to the radiation of the hot gas flow and increases the heat. Since the gas flow can be more remarkably cooled, the effect that the dielectric strength of the entire hot gas induction system in the fixed contact portion can be improved more efficiently is obtained.

[3. Third Embodiment]
FIG. 11 is a schematic cross-sectional view showing the periphery of an exhaust tube of a gas circuit breaker according to a third embodiment of the present invention. Instead of the exhaust tube 100 in the first embodiment, a terminal opening type inner tube 1101 is shown. The outer cylinder 1102 is provided so as to cover the terminal opening surface of the inner cylinder 1101 and the outer peripheral surface in the vicinity of the terminal portion.

  These inner cylinder 1101 and outer cylinder 1102 allow hot gas to pass through an inner flow path formed inside the inner cylinder 1101 and an outer flow path formed between the inner cylinder 1101 and the outer cylinder 1102. It is configured. Further, a flow guide 1103 is provided in a portion of the outer cylinder 1102 that covers the terminal opening surface of the inner cylinder 1101. Then, on the wall surfaces of the inner cylinder 1101 and the outer cylinder 1102 that form the inner and outer channels, the same direction as in the first embodiment intersects with the flow direction of the hot gas flow 30a. The extending grooves 110 are provided in at least four rows. Other configurations are the same as those in the first embodiment, such as the groove pitch P being at least 1/4 or more of the groove depth H.

  According to the third embodiment having the above-described configuration, in addition to the same operation as the first embodiment, the effective hot gas flow path can be further lengthened, and the number of grooves N Therefore, the entire hot gas flow can be cooled more efficiently and uniformly, and the volume of the hot gas itself can be contracted to suppress the pressure rise inside the stack. Is obtained. Below, this effect | action is demonstrated in detail.

  First, as described above, the number N of grooves provided in the hot gas flow path can be considered as the number of opportunities to generate a disturbance in which the hot gas flow and the room temperature gas in the groove are mixed. It is desirable to have as many as possible. According to the present embodiment, by configuring the exhaust cylinder from two cylinders, the inner cylinder 1101 and the outer cylinder 1102, the effective hot gas flow path per exhaust cylinder volume can be lengthened, and accordingly, the groove The number of columns N can be greatly increased.

  Further, when a groove is formed on the inner surface of the exhaust cylinder 100 formed of a single cylinder as shown in FIG. 1, the hot gas flow is cooled around the surface of the exhaust cylinder 100 provided with the groove 110 as described above. However, hot hot gas tends to remain in the central part of the flow. On the other hand, according to this embodiment, in the narrow flow path between the inner cylinder 1101 and the outer cylinder 1102, the cooling action is received from the grooves on both sides of the inner cylinder 1101 outer surface and the outer cylinder 1102 inner surface. Compared to a single exhaust stack 100 as in the embodiment, the entire hot gas flow can be cooled more uniformly.

  By the way, when there is some structure in the hot gas jetting direction, it may be necessary to cover the terminal part which is the gas flow jetting part of the exhaust pipe with some cover to change the jetting direction. However, in such a case, in the exhaust pipe provided with the groove, the hot gas flow is likely to be blocked as compared with a simple cylindrical exhaust pipe, and smooth exhaust to the free space in the tank becomes difficult. As a result, there is a problem that the hot gas is stagnated in the arc contact portion, and dielectric breakdown is likely to occur in the same portion, or the arc is difficult to disappear. On the other hand, according to the present embodiment, the inner cylinder 1101 is covered with the outer cylinder 1102, but the hot gas flow is effectively cooled by the groove 110, so that the volume of the hot gas itself contracts. Since an excessive increase in pressure inside the exhaust pipe can be suppressed, it is possible to discharge hot gas smoothly.

  Therefore, according to the third embodiment, in addition to the effect of the first embodiment, the effective gas path can be lengthened by forming the gas path with two cylinders. In addition to being able to cool the entire hot gas flow more efficiently and uniformly, it is possible to smoothly discharge the hot gas, so that the dielectric strength of the entire hot gas induction system in the fixed contact portion can be improved more efficiently. The effect is obtained.

[4. Fourth Embodiment]
FIG. 12 is a sectional structural view showing a gas circuit breaker according to a fourth embodiment of the present invention. In addition to the grooved exhaust tube 100 on the stationary contact portion 20 side, the hollow rod 1200 on the movable contact portion 10 side. Also, a groove 1210 is provided. This groove 1210 is a groove having the same configuration as the groove 110 provided in the exhaust tube 100 in the first embodiment. That is, at least four rows or more of grooves 1210 extending in the direction intersecting the flow direction of the hot gas flow 30b are provided on the inner surface of the hollow rod 1200, and the groove pitch P is at least 1/4 or more of the groove depth H. Has been.

  The movable-side hot gas flow 30b that has passed through the movable arc contact 11 and the hollow rod 1200 passes through several movable-side exhaust holes 17 provided in the piston 12, the cylinder 13, etc. It is discharged from the end 18 into the free space in the tank 1.

  According to the fourth embodiment having the configuration as described above, the following operation is obtained in addition to the same operation as the first embodiment. That is, the movable-side hot gas flow 30b flowing inside the hollow rod 1200 is more effectively caused by the groove 1210 by the same mechanism as the fixed-side hot gas flow 30a flowing inside the exhaust tube 100 in the first embodiment. To be cooled. Therefore, also on the movable contact portion 10 side, the insulating property of the hot gas around the exhaust hole end 18 of the movable exhaust hole 17 is recovered, and the dielectric strength between this portion and the tank 1 can be remarkably improved.

  Therefore, according to the fourth embodiment, in addition to the effect of the first embodiment, the dielectric strength in the movable contact portion can be improved efficiently, so that it is small but more reliable. The effect that a high gas circuit breaker can be provided is obtained. When the dielectric strength on the fixed contact portion side is sufficiently secured, etc., as a modification of the fourth embodiment, a groove is not provided in the exhaust tube of the fixed contact portion, and the hollow rod of the movable contact portion is provided. It is also possible to provide only grooves.

[5. Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and various other variations can be implemented within the scope of the present invention. For example, the above-described modified examples can be appropriately combined.

  In particular, as described above, the specific shape and the like of the groove provided in the exhaust pipe or the hollow rod in the present invention can be freely selected, and various shapes other than those shown in the embodiment are possible. Furthermore, it is possible to provide a combination of grooves having different shapes. That is, in the present invention, the grooves provided in the exhaust pipe or the hollow rod have at least four rows in which each row extends in a direction intersecting the traveling direction of the hot gas and is continuously arranged in the traveling direction of the hot gas. As long as it is a groove, its specific size and shape can be freely selected, and in any case, the same excellent effects as those of the above-described embodiment can be obtained.

  Moreover, in the said embodiment, although one of the contact parts was fixed and it demonstrated as an example the type which drives one, this invention is a gas circuit breaker of the type which the contact parts of both sides drive simultaneously simultaneously. Can be applied in the same manner, and similarly excellent effects can be obtained.

The typical sectional view showing the exhaust pipe circumference of the gas circuit breaker concerning the 1st embodiment of the present invention. The analysis graph which shows an example of the analysis result at the time of performing a gas flow analysis by the shape of a two-dimensional rotational symmetry as a numerical analysis of the gas circuit breaker shown in FIG. Using a metal tank type SF ₆ gas circuit breakers for the ultra high pressure system, the measured graph showing an example of a measurement result in the case of measuring the dielectric strength at the end portion of the exhaust tube. The analysis graph which shows the relationship with the hot gas temperature at the time of changing the number of grooves along a hot gas flow path in the exhaust pipe surface of FIG. Explanatory drawing which shows the groove cross-sectional shape in each case where the relationship between groove pitch P and groove depth H was changed. The analysis graph which shows an example of the analysis result which calculated | required the change of the electric field strength according to the dimensional relationship with the groove | channel in an exhaust pipe terminal part by electric field analysis. The typical sectional view showing one modification which changed the shape of the slot of the exhaust pipe shown in FIG. The typical sectional view showing another modification which changed the shape of the slot of the exhaust pipe shown in FIG. The typical sectional view showing another modification which changed the shape of the slot of the exhaust pipe shown in FIG. The typical sectional view showing the exhaust pipe circumference of the gas circuit breaker concerning the 2nd embodiment of the present invention. The typical sectional view showing the exhaust pipe circumference of a gas circuit breaker concerning a 3rd embodiment of the present invention. Sectional structure figure which shows the gas circuit breaker which concerns on the 4th Embodiment of this invention. Sectional structure figure which shows an example of the conventional gas circuit breaker. Typical sectional drawing which shows an example of the exhaust pipe of the conventional gas circuit breaker. The typical sectional view showing another example of the exhaust pipe of the conventional gas circuit breaker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tank 2 ... Arc extinguishing gas 3 ... Arc 10 ... Movable contact part 11 ... Movable arc contact 12 ... Piston 13 ... Cylinder 14 ... Puffer chamber 15 ... Insulation nozzle 16 ... Hollow rod 17 ... Movable side exhaust hole 18 ... Exhaust Hole end 20 ... Fixed contact portion 21 ... Fixed arc contact 22 ... Exhaust tube 23 ... Termination portion 30a, 30b ... Hot gas flow 100 ... (with groove) Exhaust tube 101 ... Termination portion 110, 710, 810, 910, 1210 ... Groove 111 ... Partition tip 1101 ... Inner cylinder 1102 ... Outer cylinder 1103 ... Flow guide 1200 ... (with groove) hollow rod

Claims (6)

The arc-extinguishing gas is filled in the sealed container, and the first contact portion and the second contact portion are arranged to face each other,
The first contact portion and the second contact portion are provided with a first arc contact and a second arc contact, respectively, and both contacts are in a contact conduction state during normal operation and are opened by relative movement during a shut-off operation. It is configured to generate an arc in the space between both contacts as it separates,
Gas flow generating means for blowing the arc-extinguishing gas to the arc is provided in the first contact portion,
Hot gas induction for guiding the hot gas generated by spraying the arc extinguishing gas to the arc by the gas flow generating means on the first contact portion and the second contact portion in a direction away from the both contacts. In each gas circuit breaker provided with means,
The hot gas guiding means of the second contact portion is a metal exhaust tube, and the exhaust tube is configured such that the hot gas discharged from the arc is discharged into the container from the front in the traveling direction,
On the inner surface of the exhaust tube, each row extends in a direction intersecting the traveling direction of the hot gas, and at least four rows of grooves arranged continuously in the traveling direction of the hot gas are provided .
The exhaust cylinder includes a terminal opening type inner cylinder and an outer cylinder arranged to cover the terminal opening surface of the inner cylinder and the outer peripheral surface in the vicinity of the terminal portion, and the hot gas is formed inside the inner cylinder. Is configured to pass through the inner flow path and the outer flow path formed between the inner cylinder and the outer cylinder,
The at least four rows or more of grooves are respectively provided on the wall surfaces of the inner cylinder and the outer cylinder forming the inner channel and the outer channel,
A gas circuit breaker characterized by that. The arc-extinguishing gas is filled in the sealed container, and the first contact portion and the second contact portion are arranged to face each other,
  The first contact portion and the second contact portion are provided with a first arc contact and a second arc contact, respectively, and both contacts are in a contact conduction state during normal operation and are opened by relative movement during a shut-off operation. It is configured to generate an arc in the space between both contacts as it separates,
  Gas flow generating means for blowing the arc-extinguishing gas to the arc is provided in the first contact portion,
  Hot gas induction for guiding the hot gas generated by spraying the arc extinguishing gas to the arc by the gas flow generating means on the first contact portion and the second contact portion in a direction away from the both contacts. In each gas circuit breaker provided with means,
  The hot gas guiding means of the second contact portion is a metal exhaust tube,
  The exhaust cylinder includes a terminal opening-type inner cylinder and an outer cylinder arranged so as to cover a terminal opening surface of the inner cylinder and an outer peripheral surface in the vicinity of the terminal portion, and the terminal of the inner cylinder is disposed inside the outer cylinder. A flow guide is provided at a position corresponding to the opening, and the hot gas flowing in a direction away from the two contactors through the inner flow path formed inside the inner cylinder is reversed in the traveling direction by the flow guide. Passing through the outer flow path formed between the inner cylinder and the outer cylinder, and configured to be discharged into the container,
  Each row of the inner cylinder and the outer cylinder forming the inner flow path and the outer flow path has respective rows extending in a direction intersecting the traveling direction of the hot gas, and each of the hot gas flows. At least four rows of grooves arranged continuously in the direction of travel are provided,
  A gas circuit breaker characterized by that. The exhaust tube is configured such that the shortest distance between the range where the groove is provided and the terminal opening surface is at least 5% or more of the inner diameter of the terminal opening surface.
  The gas circuit breaker according to claim 1 or 2, characterized in that. The cross section of the tip of the partition wall separating the rows of the grooves has a radius of 5 mm or less.
  The gas circuit breaker according to any one of claims 1 to 3, wherein the gas circuit breaker is provided. The groove pitch of the grooves is ¼ or more of the groove depth,
  The gas circuit breaker according to any one of claims 1 to 4, wherein the gas circuit breaker is provided. The gas circuit breaker according to any one of claims 1 to 5, wherein the arc-extinguishing gas has a global warming potential smaller than that of SF6 gas.