JPH0619941B2 - Gas circuit breaker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal buffer type gas circuit breaker also used with a suction circuit breaker, and in particular, it has excellent small current circuit breaking performance and large current of the thermal buffer circuit breaker. The present invention relates to a gas circuit breaker having a suction cutoff portion that does not deteriorate the cutoff performance.

[Conventional technology]

Generally, as a gas circuit breaker (hereinafter referred to as GCB), a buffer type is often used. Below, this kind G
The prior art of CB will be described with reference to the drawings.

FIG. 8 is a diagram showing the structure of a general buffer type GCB. In FIG. 8, 1 is a buffer chamber.

The buffer type GCB shown in FIG. 8 is configured to have a buffer chamber 1. When shutting off, the gas in the buffer chamber 1 is compressed and the gas flow generated thereby extinguishes the arc current. is there. Therefore, this buffer type GCB
Has a problem that it is difficult to significantly reduce the operating force of the GCB because there is a limit to the reduction of the operating force on the principle of compressing the gas in the buffer chamber 1.

As a conventional technique that solves the problems of such a buffer type GCB, for example, a thermal buffer type GCB combined with a suction cutoff unit described in JP-A-56-3925.
The technology regarding is known.

FIG. 9 is a diagram showing a state in which the GCB is turned on according to this conventional technique, and FIG. 10 is a diagram showing a state in the middle of a breaking operation. In FIGS. 9 and 10, 2 is a thermal buffer chamber, 3 is a thermal buffer blocking part, 4 is a suction blocking part, 5 is a suction chamber, 6 is a movable contactor, 7 is a hollow nozzle, 8 is an arc, and 9 is A fixed contact, 13 is an insulating nozzle, and 15 is a suction piston.

The GCB shown in FIG. 9 and FIG. 10 is composed of a thermal buffer shut-off portion 3 having a thermal buffer chamber 2 and a suction shut-off portion 4 having a suction chamber 5. The heat energy heats and pressurizes the gas in the heat buffer chamber 2 of the heat buffer shut-off portion 3 and blows the gas near the current zero point to extinguish the arc. Therefore, the illustrated GCB can obtain the gas blowing pressure against the arc by the energy of the arc itself, and can significantly reduce the operating force. However, since it is not possible to expect an increase in the gas pressure in the thermal buffer chamber 2 due to the arc energy when only a small current is interrupted with the thermal buffer interrupting unit 3, only the thermal buffer interrupting unit 3 in FIG.
The GCB shown in FIG. 0 is provided with a suction blocker 4 as an auxiliary blocker.

By including the suction blocking unit 4, the
The GCB shown in FIG. 0 operates as follows when a small current is cut off.

During the shutoff operation, the suction piston 15 moves to the left from the state shown in FIG.
As shown in the figure, the gas is drawn into the suction chamber 5 through the hollow nozzle 7 of the movable contact 6. As a result, the arc generated when the current is cut off is ignited in the hollow nozzle 7 and is extinguished by the gas flow in the hollow nozzle 7, as indicated by the solid line in FIG.

This GCB is an excellent one because it has an advantage that the operation force by the suction cutoff portion 4 as an auxiliary cutoff means does not increase and the structure of the entire apparatus does not become complicated, but it has the following drawbacks. is doing.

That is, the first is that it is difficult to reliably draw the small current arc into the hollow nozzle 7 formed of metal,
As shown by the dotted line in FIG. 10, the arc may ignite at the tips of the fixed contactor 9 and the movable contactor 6, and it is difficult to extinguish the arc in this case. In order to draw the arc generated as shown by the dotted line in FIG. 10 into the hollow nozzle 7, a strong gas flow into the hollow nozzle 7 must occur, but the volume of the suction chamber 5 and the hollow nozzle 7 The gas volume of the surrounding space is overwhelmingly larger than the flow passage cross-sectional area of 7, and the gas flow is weakly generated only near the inlet of the hollow nozzle 7. Therefore, the drawing of the arc into the hollow nozzle 7 is a stochastic phenomenon, and the success or failure of the current interruption is mixed even if all the conditions are the same.

Secondly, when the gas in the thermal buffer chamber 2 is heated by the arc heat when the large current is cut off, it is necessary to confine the arc energy and the gas in the thermal buffer chamber 2 so as not to flow out to the outside. In the GCBs shown in FIGS. 10 and 10, the gas flow path to the suction chamber 5 opens from the beginning of the shutoff operation, and the arc energy and the gas flow out to the suction chamber 5, which reduces the efficiency of the thermal buffering action. That is the point.

Thirdly, since the movable contact 6 has the electrode structure having the hollow nozzle 7, the electrode diameter is inevitably increased, and accordingly, the diameter of the insulating nozzle 13 is inevitably increased. This is because it is difficult to set the optimum nozzle diameter that is determined from the current interruption performance, and the performance of the GCB is deteriorated.

As described above, the GCB shown in FIGS. 9 and 10 has a problem in interrupting both large current and small current.

Further, as another conventional technique of the thermal buffer type GCB combined with the suction cutoff portion, for example, the technique described in JP-A-59-12527 is known, which will be described below with reference to the drawings.

FIG. 11 is a diagram showing a state in which a GCB is turned on according to another conventional technique, FIGS. 12 and 13 are diagrams showing a state in the middle of a breaking operation, and FIG. 14 is a diagram explaining its characteristics. In FIGS. 11 to 13, 14 is an insulating nozzle, 24 is a vent hole, 25 is a suction port, and other reference numerals are FIGS. 8 to 1.
This is the same as in the case of FIG.

The GCBs shown in FIGS. 11 to 13 move the movable contact 6 to the left from the position in the closed state shown in FIG. 11 during the shutoff operation, and sequentially move to the positions shown in FIGS. 12 and 13. Move to. Therefore, the suction chamber 5 has its volume increased along with the operation of the movable contact 6 by the piston 15 attached to the movable contact 6, and the suction port of the ring-shaped space formed by the insulating nozzle 14 and the movable contact 6. Aspirate gas from 25. On the other hand, the volume of the buffer chamber 1 is reduced by the operation of the piston 15, and the gas is ejected from the hollow nozzle portion 7 through the vent hole 24 provided in the movable contactor 6. The GCB shown in FIGS. 11 to 13 cuts off a small current at the position shown in FIG. That is, at this position, the gas blown from the hollow nozzle 7 is
It becomes a gas flow sucked from 5, and the arc 8 is extinguished by this gas flow.

The GCBs shown in FIGS. 11 to 13 described above are intended to surely cut off a small current by using both blowing and sucking gas, but the explanation is given with reference to FIGS. 9 and 10. It has the same problem as GCB.

That is, in the state of the interruption operation as shown in FIG. 12, the gas flow due to the suction action occurs only in the vicinity of the insulating nozzle 14, so that the combined effect of the above-mentioned spraying and suction cannot be obtained.

Moreover, in the state shown in FIG. 13, the following problems occur. It is generally known that the degree of negative pressure generation and positive pressure generation increases as the volume change rate increases. Therefore, the maximum negative pressure is generated in the suction chamber 5 at the beginning of the shutoff operation, and the maximum positive pressure is generated in the buffer chamber 1 in the latter half of the shutoff operation. This relationship is shown in FIG. As can be seen from this figure, the pressure of the suction chamber 5 shows the maximum value of the negative pressure at the initial stage of the shutoff operation, and then returns to the filled pressure by the gas suction from the suction port 25. On the other hand, the pressure in the buffer chamber 1 shows the maximum value in the latter half of the shutoff operation. The position of the movable contactor 6 shown in FIG. 13 corresponds to the vicinity of the position shown by the dotted line in FIG. 14, and the suction action of the suction chamber 5 has already weakened, and the combined effect of spraying and suction is shown. Cannot be fully exerted.

Further, when a large current is cut off, this GCB causes the following problems. That is, when a large current is cut off, the high temperature gas flow generated in the thermal buffer chamber 2 flows into the buffer chamber 1 through the hollow nozzle 7 and increases the pressure in the buffer chamber 1.
This means that in addition to the problem of reducing the efficiency of the thermal buffer action described in FIG. 9, a reaction force against the operating force is generated due to the increase in the pressure of the buffer chamber 1, and the operating force must be increased. Cause problems. That is, the GCBs shown in FIGS. 11 to 13 also have a problem that the operating force cannot be reduced, and are the same as the GCBs shown in FIGS. 9 and 10 due to the restriction of the electrode diameter. It has a serious problem.

[Problems to be Solved by the Invention] As described above, the GCB according to the related art has the stability of the breaking performance at the time of breaking a small current and the arc heat at the time of breaking a large current.
There has been a problem that sufficient consideration has not been given to the effective use of the gas flow, and sufficient performance improvement has not been achieved.

The object of the present invention is to solve the above-mentioned problems of the prior art,
An object of the present invention is to provide a gas circuit breaker with a low operating force, an excellent large-current breaking performance, and a stable small-current breaking performance.

[Means for Solving the Problems]

According to the present invention, the above object is achieved by making it possible to perform the suction action in the latter stage of the blocking operation, and by providing an insulating nozzle for controlling the suction gas flow between the fixed contact and the movable contact. To be done.

[Action]

By providing the above-mentioned means, it is possible to effectively use the arc heat at the time of breaking a large current, and since the arc is drawn into the insulating nozzle during the suction operation, the arc is reliably spotted in the gas flow. It becomes possible to make an arc,
It is possible to obtain stable breaking performance against a large current and a small current.

〔Example〕

An embodiment of a gas circuit breaker according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing a closed state of an embodiment of the present invention, FIG. 2 is a sectional view showing the same cutoff state, FIG. 3 is a diagram for explaining a large current interruption operation, and FIG. 4 is a small current. It is a figure explaining operation of interruption. 1 to 4, 10, 12
Is a terminal, 13 is a current collector, 16 is a suction cylinder, 17 is a field shield ring shield, 18 is a rod, and other reference numerals are the same as those in FIGS. 8 to 14.

The GCB according to one embodiment of the present invention is composed of the thermal buffer blocker 3 and the suction blocker 4 as in the case of the prior art. Since the movable contact 6 does not have a hollow structure but has a rod-shaped structure as shown in the figure, the insulating nozzle 13 of the thermal buffer blocker 3 has its diameter set to an optimum dimension only from the viewpoint of thermal buffer action. It can be adopted and configured. The suction blocking unit 4 includes a suction cylinder 16 having an insulating nozzle 14, a suction piston 15 movable in the suction cylinder 16 as the movable contact 6 moves, and a movable contact connected to the piston 15. 6 and an electric field mitigating ring shield 17 attached to the suction piston 15 by a plurality of rods 18 passing through a through hole formed in the suction cylinder 16. Suction chamber 5
Is composed of a suction piston 15, a suction cylinder 16 and an insulating nozzle 14, and the gas suction port of the insulating nozzle 14 has a movable contact 6 when the GCB is turned on.
The movable contact 6 is closed by the
Are configured to be opened when passing through the insulating nozzle 14.

In the closed state shown in FIG. 1 of the embodiment of the present invention having the above-mentioned structure, the current is collected by the terminal 10, the fixed contactor 9 of the thermal buffer blocking section 3, the movable contactor 6, and the suction blocking section 4. It flows through the electron 11 and the terminal 12. In the shut-off state shown in FIG. 2, the movable contact 6 is located downstream of the insulating nozzle 14 in the suction chamber 5.

Next, the current interruption operation will be described.

FIG. 3 shows a state when a large current is cut off. When the breaking operation is started, the movable contact 6 moves, and the tip of the moving contact 6 passes through the insulating nozzle 13, the gas in the heat buffer chamber 2 heated and pressurized by the arc generated by the current breaking operation is released. , The arc 8 generated between the fixed contact 9 and the tip of the movable contact 6. As a result, the arc 8 is extinguished and the current interruption is completed. This interruption action is
Since it is performed without wasteful discharge of gas and arc energy at the initial stage of operation as described in the prior art, it is possible to select the optimum nozzle diameter described above and obtain an effective shutoff performance by a thermal buffer.

FIG. 4 shows a state when the small current is cut off. Since the arc energy is small, the interruption of the small current cannot be performed by the arc extinguishing by the thermal buffer, and the movable contact 6 passes through the insulating nozzle 14 of the suction chamber 5 to the downstream side of the insulating nozzle 14. Done when positioned. That is, from the time when the movable contact 6 passes through the insulating nozzle 14 of the suction chamber 5, a gas flow into the suction chamber 5 occurs, and this gas flow blocks a small current. The small current arc 8 is an insulating nozzle 8
Since it is held in the gas flow, the gas flow causes the arc to be extinguished very stably and the current to be cut off. As shown in FIG. 14, the negative pressure in the suction chamber 5 at the time of this operation is generated at the initial stage of the shutoff operation, but when the gas is sucked from the insulating nozzle 14, the movable contact 6 passes through the insulating nozzle 14. Since it is later, the negative pressure in the suction chamber is maintained during this period, the gas flow in the suction nozzle 14 at the start of suction becomes large, and the arc 8 can be effectively extinguished. .

The above-described embodiment of the present invention can effectively and reliably cut off the current both when the current is large and when the current is small.

Next, another embodiment of the present invention will be described.

FIG. 5 is a sectional view showing a throwing state of another embodiment of the present invention,
6 (a) and 6 (b) are views for explaining the shutoff operation. In FIGS. 5 and 6 (a) and (b), 19 and 20 are engaging portions, 2
Reference numeral 1 is a compression spring, and other symbols are the same as those in FIGS. 1 to 4.

Another embodiment of the present invention shown in FIG.
5 is engaged with the movable contactor 6 in a semi-floating manner, and when the engaging portions 19 and 20 of the movable contactor 6 and the suction piston 15 are not engaged, the suction piston 15 has the compression spring 2
It is held at the lower part of the insulating nozzle 14 by 1.

The interruption operation of the large current is performed at the position shown in FIG. 6 (a) when the interruption operation is started and the movable contact 6 moves and is removed from the insulating nozzle 13. The operation shown in FIG. This is the same as the case of the example, and the interruption operation is also the same. In this embodiment, the suction piston 15 is still in this state.
Is not engaged with the movable contactor 6, and the suction piston 15 is located below the insulating nozzle 14.

The small current interruption operation is performed when the movable contact 6 moves to the position shown in FIG. 6 (b). That is, at this time, the movable contactor 6 is engaged with the suction piston 15 by the engaging portion 19 to move the suction piston 15, and
The tip of the movable contact 6 passes through the insulating nozzle 14 and is located downstream of the insulating nozzle 14. This state is the same as in the case of FIG. 4, and the interruption operation in this case is performed by extinguishing the arc exactly as in the case of FIG.

The embodiment shown in FIGS. 5 and 6 (a) and (b) is shown in FIGS.
Compared to the embodiment described with reference to FIG. 4, the movable contact 6
The length of the suction cylinder 16 can be shortened with respect to the stroke length, and the current interruption performance can be made equal to that of the embodiment shown in FIGS. 1 to 4.

FIGS. 7 (a) and 7 (b) are a cross-sectional view of a closing state and a state in the middle of a breaking operation according to still another embodiment of the present invention. The reference numerals in the drawings are the same as those in the other drawings.

In this embodiment, a small hollow nozzle 7 is provided on the movable contact 6 in the embodiment described with reference to FIGS. The hollow nozzle 7 is not intended to draw an arc into the hollow nozzle 7 unlike the case of the prior art described with reference to FIGS. This is to generate a gas flow, and the nozzle diameter may be small, and accordingly, it is not necessary to increase the electrode diameter of the movable contactor 6. This hollow nozzle 7
As described above, a slight gas flow is generated between the electrodes at the initial stage of the cutoff operation, and the gas flow cuts off a current of several amps to several tens of amperes such as a no-load charging stream and an exciting current. In general, it is possible to utilize the property that interruption of a small current to this extent is possible if some kind of gas flow occurs between the electrodes.
Therefore, in the embodiment shown in FIGS. 7 (a) and 7 (b), the gas flow through the hollow nozzle 7 for interrupting the small current is cut off at the initial stage of the interruption operation as shown in FIG. 7 (b). It is generated and the small current is cut off.

In the embodiment shown in FIGS. 7 (a) and 7 (b), since the movable contact 6 is provided with the hollow nozzle 7, the number is smaller than that of the conventional technique described with reference to FIGS. In order to reduce this drawback, the hollow nozzle 7 is sucked into the tip of the movable contact 6 so that the hollow nozzle 7 and the suction chamber 5 are not communicated with each other at the beginning of the breaking operation. The structure is such that it communicates with the outside at an intermediate position with the piston 15.

The embodiment of the present invention shown in FIGS. 1 to 7 described above does not discriminate between a large current cutoff and a small current cutoff, and a large current cutoff and a small current cutoff priority position are set in the first and second half of the cutoff process, respectively. However, if the GCB itself can determine the magnitude of the breaking current and select the breaking means that matches the magnitude of the breaking current,
A more reasonable breaker can be obtained.

FIG. 15 is a sectional view of still another embodiment of the present invention in which the GCB itself can determine the magnitude of the breaking current and select the breaking means. In FIG. 15, 22 is a superconducting contact, and other reference numerals are the same as those in FIGS. 1 to 7.

In the embodiment shown in FIG. 15, the movable contact is composed of a room temperature superconducting contact 22 for interrupting a small current and a movable contact 6 for interrupting a large current, and accordingly, a breaker for a small current. And a large current interruption unit are arranged in parallel. Since the breaker equipped with a room temperature superconducting contactor that cuts off a small current cannot make effective use of the arc energy because it is an arc caused by a small current, the results are shown in Figs. 1 to 7 (a) and (b). The suction blocking unit 4 similar to that described is provided. Further, since the breaking portion for breaking a large current can sufficiently use the arc energy, it is configured to have only the thermal buffer breaking portion 3. Then, the limiting current of the interrupting portion that interrupts the small current is set to match the critical current of the room temperature superconducting contact 22. With such a configuration, a small current such as a load current flows on the side of the interruption section having the room temperature superconducting contact 22, and accordingly, the interruption of such a small current is performed by this interruption section. When a large current is generated due to an accident or the like, the superconducting state of the room temperature superconducting contact 22 is broken, and the current flows to the side of the movable contact 6 for breaking the large current. As a result, the interruption of the large current is performed by the interruption unit having the movable contact 6 for interrupting the large current.

According to the embodiment of the present invention shown in FIG. 15, the current when the small current is cut off flows through the contact 22 and the current when the large current is cut off is
Since the current flows through the contactor 6, it is possible to cut off the current by the breaking unit of a method suitable for the magnitude of the current.

〔The invention's effect〕

As described above, according to the present invention, when the large current is interrupted, the gas heating due to the arc heat is effectively utilized, the decrease in the gas density at the initial stage of the interrupting operation is prevented, and the insulating nozzle diameter suitable for interrupting the large current is selected. By making it possible, and by making it possible to hold a small current arc in the gas flow by an insulating nozzle when breaking a small current, it has a low operating force, excellent large current breaking performance, and small It is possible to provide a gas circuit breaker with stable current interruption performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing a closed state of an embodiment of the present invention, FIG. 2 is a sectional view showing the same cutoff state, FIG. 3 is a diagram for explaining a large current interruption operation, and FIG. 4 is a small current. FIG. 5 is a cross-sectional view showing the closing operation of another embodiment of the present invention, FIGS. 6 (a) and 6 (b) are views explaining the breaking operation, and FIG. 7 ( (a) and (b) are cross-sectional views of still another embodiment of the present invention in a closed state and a state in the middle of a breaking operation, FIG. 8 is a diagram showing a structure of a general buffer type GCB, and FIG. ，
FIG. 10 is a diagram showing a state of charging a GCB according to the prior art and a diagram showing a state in the middle of its breaking operation, FIG. 11 is a diagram showing a state of charging a GCB according to another conventional technique, and FIGS. 12 and 13 are FIG. 14 is a diagram showing a state in the middle of the shutoff operation, FIG. 14 is a diagram for explaining its characteristics, and FIG. 15 is a diagram showing a configuration of still another embodiment of the present invention. 1 ... Buffer room, 2 ... Thermal buffer room, 3 ... Thermal buffer blocking section, 4 ... Suction blocking section, 5 ... Suction chamber, 6
...... Movable contact, 7 ...... Hollow nozzle, 8 ...... Arc, 9
...... Fixed contacts, 10,12 ...... Terminals, 11 ...... Current collectors,
13, 14 ... Insulation nozzle, 15 ... Suction piston,
16 ... Suction cylinder, 19, 20 ... Engaging portion, 21
...... Compression spring, 22 …… Superconducting contact, 24 …… Vent hole, 25 …… Suction port.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuharu Seki 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi, Ltd. (56) References JP-A-60-167224 (JP, A) -180339 (JP, U)

Claims (5)

[Claims] 1. A pair of contacts comprising a fixed contact and a movable contact, and a heating chamber for heating and pressurizing gas by arc energy generated between the contacts when the fixed contact is mounted and the breaking operation is performed. A thermal puffer cutoff section consisting of a nozzle or the like for blowing a heated and pressurized gas to the generated arc,
In a gas circuit breaker comprising a suction piston interlocking with the movable contact and a suction blocking section composed of a suction cylinder surrounding the piston, a gas suction port of the suction blocking section is formed by an insulating nozzle, and the insulating nozzle Is closed by the movable contactor in a closed state, and at the time of a blocking operation, the insulating nozzle of the suction blocker, even after the movable contactor passes through the nozzle of the thermal puffer blocker and opens the nozzle, The high-temperature gas, which is closed by the movable contactor for a certain period and is exhausted from the heat puffer blocking part, is exhausted to the outer space of the suction blocking part, and the suction blocking part is opened after the movable contact passes through the insulating nozzle. A gas circuit breaker characterized by: 2. The gas circuit breaker according to claim 1, wherein the movable contactor and the suction piston are fixedly coupled to each other. 3. The gas circuit breaker according to claim 1, wherein the movable contact and the suction piston are engaged in a semi-floating manner. 4. The gas according to claim 1, 2 or 3, wherein the movable contactor is provided with a hollow nozzle communicating with the outside in a throwing state at a tip portion thereof. Circuit breaker. 5. The movable contactor is a contactor made of a room-temperature superconducting material, and a thermal puffer type interrupter is provided in parallel with an interrupter having the contactor.
A gas circuit breaker according to item 2, item 3, item 3, or item 4.