JP2020155303A - Gas circuit breaker - Google Patents

Abstract

To provide a gas circuit breaker for improving a breaking performance of a small lead current by relaxing an electric field of a fixed side arc contactor without deteriorating insulation coordination.SOLUTION: The gas circuit breaker has: a gas tank filled with an insulating gas; a movable side main contactor housed inside the gas tank; a fixed side main contactor installed so that it can be contacted and separated from the movable side main contactor; and an insulating nozzle installed on an inner peripheral side of the fixed side main contactor. The circuit breaker has: a nozzle guide installed in a cylindrical shape inside the fixed side main contactor; and a movable shield sliding around an inner circumference of the nozzle guide.SELECTED DRAWING: Figure 5

Description

The present invention relates to a gas circuit breaker, and more particularly to a gas circuit breaker that extinguishes an arc by blowing an insulating gas onto an arc generated between arc contacts when a current is interrupted.

In recent years, the voltage and current of electric power systems have been increasing, and the capacity of gas circuit breakers has been increasing in order to obtain the required breaking performance. On the other hand, miniaturization by optimizing the circuit breaker structure, exhaust part structure, and shield structure of the gas circuit breaker, and cost reduction by using a spring operator as the actuator are progressing.

In addition, the gas circuit breaker has various shut-off duties, and may cut off a large current of several tens of kA order such as a short circuit accident or a small current of several hundred A order such as a leading small current. is there.

When this small lead current is cut off, the current is cut off even immediately after the pole is opened. However, in this case, since the distance between the arc contacts is small, re-ignition may occur between the arc contacts when a high voltage of a commercial frequency is applied from the power system. This re-ignition is a dielectric breakdown phenomenon that occurs after a quarter cycle or more of the commercial frequency has elapsed. When this re-ignition occurs, an overvoltage is applied to the power system, so it is necessary to prevent the occurrence of re-ignition.

It is important to relax the electric field between the arc contacts in order to improve the breaking performance of the small leading current. As measures to relax the electric field between the arc contacts, there are early recovery of the electric field between the poles by improving the breaking speed, installation of an electric field relaxation shield, and an increase in the diameter of the electrode shape.

However, in recent years, such measures have become difficult due to demands such as miniaturization of the blocking portion structure and reduction of the operating force of the actuator.

In addition, excessive electric field relaxation of the arc contact by the electric field relaxation shield may deteriorate the insulation coordination and cause dielectric breakdown between the movable side main contact and the fixed side main contact. Since there is no gas flow of insulating gas between such main contacts, when an arc is generated between the main contacts, the insulating gas can be blown onto the arc to extinguish the arc. It may not be possible, that is, the current may not be cut off.

As a background technique in this technical field, there is Japanese Patent Application Laid-Open No. 2012-146405 (Patent Document 1). In Patent Document 1, the electric field relaxation shield is floating and can operate in the central axis direction, and the central axis is released as the coil spring is released during the breaking operation by the coil spring coupled to the proximal end portion. A gas circuit breaker configured to operate towards the movable contact in the direction is described (see summary).

According to Patent Document 1, immediately after the arc contact is opened, the electric field relaxation effect of the electric field relaxation shield can be suppressed to avoid a recurrence arc between the contacts, and when the arc contact is opened, the electric field is generated. It is stated that the mitigation shield can exert an electric field mitigation effect by moving along the axial direction, thereby providing a gas circuit breaker that ensures good lead and small current breaking performance. (See summary).

Japanese Unexamined Patent Publication No. 2012-146405

Patent Document 1 describes a gas circuit breaker that can operate in the central axis direction, has an electric field relaxation shield urged by a coil spring coupled to a proximal end portion, and secures good lead small current breaking performance. Are listed.

However, in the gas circuit breaker described in Patent Document 1, the electric field relaxation shield is installed outside the support (installed at a position where the electric field relaxation shield and the fixed side arc contactor are separated from each other), and the fixed side arc contactor is installed. It is considered that the electric field relaxation effect for relaxing the electric field is small.

Therefore, the present invention provides a gas circuit breaker that improves the breaking performance of a small forward current by relaxing the electric field of the fixed-side arc contactor without deteriorating the insulation coordination.

In order to solve the above problems, the gas breaker of the present invention is installed so as to be detachable from a gas tank filled with an insulating gas, a movable side main contactor housed inside the gas tank, and a movable side main contactor. A nozzle guide having a fixed-side main contact and an insulating nozzle installed on the inner peripheral side of the fixed-side main contact, and a nozzle guide installed in a tubular shape inside the fixed-side main contact, and a nozzle guide. It is characterized by having a movable shield that slides on the inner peripheral side.

According to the present invention, it is possible to provide a gas circuit breaker that improves the breaking performance of a small traveling current by relaxing the electric field of the fixed-side arc contactor without deteriorating the insulation coordination.

Issues, configurations and effects other than those described above will be clarified by the explanation of the following examples.

It is sectional drawing explaining the schematic structure of a gas circuit breaker. It is sectional drawing explaining the schematic structure of the closing state when the electric field shield is installed inside the fixed side main contact of a gas circuit breaker. It is sectional drawing explaining the high electric field part between the electric field shield and the movable side main contact during the breaking operation when the electric field shield is installed inside the fixed side main contact of a gas circuit breaker. It is sectional drawing explaining the schematic structure in the charged state of the gas circuit breaker of Example 1. FIG. It is sectional drawing explaining the schematic structure in the middle of the shutoff operation of the gas breaker of Example 1. FIG. It is sectional drawing explaining the schematic structure in the cut-off state of the gas circuit breaker of Example 1. FIG. It is sectional drawing explaining the schematic structure in the middle of the shutoff operation of the gas breaker of Example 2. FIG. It is sectional drawing explaining the schematic structure in the middle of the shutoff operation of the gas breaker of Example 3. FIG. It is sectional drawing explaining the schematic structure in the middle of the shutoff operation of the gas breaker of Example 4. FIG.

Hereinafter, examples of the present invention will be described with reference to the drawings. The same or similar configurations may be designated by the same reference numerals, and if the descriptions are duplicated, the description may be omitted.

First, a schematic configuration of the gas circuit breaker described in this embodiment will be described.

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a gas circuit breaker.

The gas circuit breaker described in this embodiment is a gas tank 1 filled with an insulating gas (SF ₆ gas), a movable arc contactor 2 housed inside the gas tank 1, and a movable arc contactor 2. It is in contact with the fixed side arc contactor 3 which is installed possible (opposite to enable the opening and closing operations), the movable side main contactor 5 housed inside the gas tank 1, and the movable side main contactor 5. It has a fixed-side main contactor 4 which is installed so as to be separable (opposite to enable opening and closing operations). Then, the movable side main contact 5 and the fixed side main contact 4 form a main contact. The movable side arc contact 2 and the fixed side arc contact 3 are energized with an electric current after the opening operation of the main contact to generate an arc.

In this embodiment, SF ₆ gas is used as the insulating gas, but the insulating gas is not limited to SF ₆ gas, and other insulating gases such as dry air and nitrogen gas can also be used.

Further, the gas circuit breaker described in this embodiment uses a puffer type gas circuit breaker that obtains the pressure of the insulating gas by mechanical compression of the puffer piston 7, but the gas circuit breaker is not limited to such a gas circuit breaker. It can also be applied to a gas circuit breaker having one or both of a fixed volume thermal expansion chamber and a mechanical compression chamber.

Then, in order to cut off a large current such as a short circuit accident, when the opening command is transmitted, the fixing side is provided by the actuator (not shown) via the hollow rod 6 and the insulating rod (not shown). The arc contact 3 and the movable arc contact 2, the fixed side main contact 4 and the movable main contact 5 are physically separated from each other (from the closing state to the blocking state).

That is, the movable arc contact 2 and the movable main contact 5 move to the right side in the drawing, and the fixed arc contact 3 and the movable arc contact 2, the fixed main contact 4 and the movable main contact are moved. 5 and 5 are physically separated.

Even after the fixed-side main contact 4 and the movable-side main contact 5 are separated from each other (during the breaking operation), a current flows between the fixed-side arc contact 3 and the movable-side arc contact 2. , An arc is generated in the high electric field portion 14. Insulating gas is blown onto the generated arc to extinguish the arc.

This insulating gas stays in the puffer chamber 9 formed between the puffer cylinder 8 coaxially installed on the outer peripheral side of the hollow rod 6 and the hollow rod 6. Then, the insulating gas staying in the puffer chamber 9 is compressed by the movement of the puffer cylinder 8 and the hollow rod 6 by the puffer piston 7 formed between the puffer cylinder 8 and the hollow rod 6.

That is, the puffer chamber 9 is formed by the puffer cylinder 8 and the hollow rod 6 coaxially installed on the inner peripheral side of the puffer cylinder 8, and the inside is hollow. Insulating gas stays in the puffer chamber 9. Then, a high-temperature and high-pressure gas that extinguishes the arc flows into the hollow rod 6. The puffer piston 7 slides in a space formed between the puffer cylinder 8 and the hollow rod 6. The puffer piston 7 is fixed to a mounting seat installed on the inner peripheral surface of the gas tank 1. As described above, the puffer chamber 9 is composed of the puffer cylinder 8, the puffer piston 7, and the hollow rod 6, and the insulating gas staying in the puffer chamber 9 is compressed by the puffer piston 7.

The insulating gas sprayed on the arc is compressed inside the puffer chamber 9. The insulating gas is compressed by the puffer cylinder 8 and the hollow rod 6 moving relative to the puffer piston 7. That is, the driving force of the actuator is transmitted to the puffer cylinder 8 and the hollow rod 6 via the insulating rod (not shown) connected to the actuator (not shown), and the puffer cylinder 8 and the hollow rod 6 are transferred. It moves and the insulating gas inside the puffer chamber 9 is compressed.

Then, the high-pressure insulating gas compressed inside the puffer chamber 9 is brought into contact with the fixed-side arc contactor 3 and the movable-side arc contactor 2 via the insulating nozzle 10 forming a space communicating with the puffer chamber 9. It is sprayed on the arc generated between them, and the arc is extinguished.

The fixed-side main contact 4 is installed at the tip of the fixed-side exhaust stack 13. The movable arc contact 2 is installed on the inner peripheral side of the movable child cover 11. A shield 12 is installed on the outer peripheral side of the fixed-side main contactor 4. Further, the insulating nozzle 10 is installed on the inner peripheral side of the fixed side main contactor 4.

Then, the fixed-side exhaust stack 13 is electrically connected to the fixed-side arc contact 3 via the support structure.

In the energized state (closed pole state, closed state), the electrically connected movable side arc contactor 2, hollow rod 6, puffer piston 7, puffer cylinder 8 and movable side main contactor 5 are on the fixed side. Is electrically connected to.

On the other hand, the case of cutting off a small current such as a small lead current is basically the same as the case of cutting off a large current.

That is, the high-voltage insulating gas compressed in the puffer chamber 9 cuts off the small current generated between the fixed-side arc contactor 3 and the movable-side arc contactor 2. In this case, the distance between these arc contacts is short.

In this way, when the arc time is cut off in a state close to zero (when a small current such as a small lead current is cut off), a high electric field portion 14 is generated between these arc contacts, and dielectric breakdown occurs. there's a possibility that. In order to prevent dielectric breakdown, it is necessary to relax the electric field between the arc contacts without deteriorating the insulation coordination.

Then, after the arc generated between the arc contacts is extinguished, a high voltage of a commercial frequency is applied from the power system between the main contacts and the poles between the arc contacts. In particular, it is important to recover the insulation between the poles faster than the voltage of the power system applied according to the commercial frequency, and it is important to relax the electric field of the arc contactor.

Here, first, a comparative example will be described.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a closing state when an electric field shield is installed inside a fixed-side main contactor of a gas circuit breaker.

In this comparative example, a fixed electric field shield 15 is installed inside the fixed side main contactor 4. As a result, the effect of electric field relaxation on the fixed-side arc contactor 3 can be increased.

FIG. 3 is a cross-sectional view illustrating a high electric field portion between the electric field shield and the movable side main contact during the breaking operation when the electric field shield is installed inside the fixed side main contact of the gas circuit breaker.

As shown in FIG. 3, immediately after the electrode is opened (during the breaking down operation), the electric field between the electric field shield 15 and the movable side main contact 5 becomes a high electric field with respect to the arc contacts, and the high electric field portion 16 becomes It can occur, and dielectric breakdown can occur.

FIG. 4 is a cross-sectional view illustrating a schematic configuration of the gas circuit breaker of the first embodiment in a charged state.

Therefore, the gas circuit breaker described in this embodiment has a conductive movable shield 20 inside the fixed-side main contactor 4 that operates in association with the circuit breaker operation. As a result, the electric field of the fixed-side arc contactor 3 can be relaxed without deteriorating the insulation coordination, and the breaking performance of the small leading current can be improved.

The gas circuit breaker described in this embodiment is basically the same as the gas circuit breaker shown in FIG.

Then, in the gas circuit breaker described in this embodiment, even after the fixed side main contactor 4 and the movable side main contactor 5 are separated from each other, between the fixed side arc contactor 3 and the movable side arc contactor 2. A current flows through the circuit and an arc is generated.

However, when cutting off a small current such as a small lead current, the arc generated between the arc contacts is very small, so the arc should be extinguished even when the blowing pressure of the insulating gas is small. A high voltage of commercial frequency is applied from the power system between the main contacts and the poles between the arc contacts.

At this time, according to the present embodiment, even immediately after the opening of the pole (during the breaking down operation), the electric field between the movable shield 20 and the movable main contact 5 is high with respect to the arc contacts. No high electric field portion is generated, and dielectric breakdown does not occur. That is, it is possible to achieve both insulation coordination and electric field relaxation.

Then, the movable shield 20 slides (moves) on the inner peripheral side of the conductive nozzle guide 24 installed in a tubular shape inside the fixed side main contactor 4. Further, the movable shield 20 is formed with a movable side stopper (projection portion) 22 and a fixed side stopper (projection portion) 23 on the inner peripheral side thereof. Further, a nozzle protrusion 21 is formed on the outer peripheral side of the insulating nozzle 10. The nozzle protrusion 21 operates in the axial direction, and when it comes into contact with the movable side stopper 22 or the fixed side stopper 23, the movable shield 20 also operates in the axial direction. The nozzle protrusion 21 moves between the movable side stopper 22 and the fixed side stopper 23.

That is, the gas circuit breaker described in this embodiment slides on the inner peripheral side of the nozzle guide 24 and the nozzle guide 24 installed in a tubular shape inside the fixed side main contactor 4, and is on the inner peripheral side thereof. It has a movable shield 20 in which a movable side stopper 22 and a fixed side stopper 23 are formed, and an insulating nozzle 10 in which a nozzle protrusion 21 is formed on the outer peripheral side.

As a result, the effect of electric field relaxation on the fixed-side arc contactor 3 can be increased, and dielectric breakdown between the movable shield 20 and the movable-side main contactor 5 does not occur. Then, the dielectric strength between the arc contacts can be improved, and the breaking performance of a small leading current can be improved.

As shown in FIG. 4, the nozzle protrusion 21 is in contact with the fixed side stopper 23 when the gas circuit breaker is turned on.

FIG. 5 is a cross-sectional view illustrating a schematic configuration during the shutoff operation of the gas circuit breaker of the first embodiment.

As shown in FIG. 5, the nozzle protrusion 21 is in contact with the movable stopper 22 during the shutoff operation (initial stage) of the gas circuit breaker.

The movable shield 20 is in an arc contact with the tip of the fixed-side arc contact 3 (movable-side tip) so that the tip of the movable shield 20 (movable-side tip) does not protrude. It is possible to prevent the electric field between the children and the main contacts from being affected. That is, since the distance between the movable side main contact 5 and the tip of the movable shield 20 is larger than the distance between the arc contacts, dielectric breakdown does not occur.

Further, in this way, the movable shield 20 operates on the movable side (right side in the drawing) when the nozzle protrusion 21 comes into contact with the movable side stopper 22 during the shutoff operation. Therefore, it does not cause excessive electric field relaxation between the arc contacts and does not affect the insulation coordination.

FIG. 6 is a cross-sectional view illustrating a schematic configuration of the gas circuit breaker of the first embodiment in a circuit breaker state.

As shown in FIG. 6, the movable shield 20 operates on the movable side (right side in the drawing) together with the insulating nozzle 10 to relax the electric field of the fixed arc contactor 3.

Further, in the cut-off state of the gas circuit breaker, the effect of electric field relaxation by the shield 12 can be enhanced by setting the positional relationship so that the tip of the movable shield 20 does not protrude with respect to the tip of the shield 12. It is possible to prevent dielectric breakdown between the movable shield 20 and the movable side main contactor 5.

According to this embodiment, it is possible to improve the dielectric strength between the arc contacts and improve the breaking performance of the small current without causing dielectric breakdown between the movable shield 20 and the movable main contact 5. ..

On the other hand, during the closing operation, the movable shield 20 operates on the fixed side (left side in the drawing) when the nozzle protrusion 21 comes into contact with the fixed side stopper 23. Even when a high voltage is applied due to a surge during the closing operation, when the distance between the poles becomes small, the movable shield 20 retracts to the fixed side (left side in the figure) with respect to the fixed arc contactor 3. For example, even when dielectric breakdown occurs between the poles, it is possible to prevent discharge to the movable shield 20 and suppress deterioration of the movable shield 20.

As described above, according to the present embodiment, it is possible to improve the breaking performance of the advancing small current by relaxing the electric field of the fixed side arc contactor 3 without deteriorating the insulation coordination.

FIG. 7 is a cross-sectional view illustrating a schematic configuration during the shutoff operation of the gas circuit breaker of the second embodiment.

Compared to the gas circuit breaker described in the first embodiment, the gas circuit breaker described in this embodiment has an elastic body A25 between the nozzle protrusion 21 and the fixed side stopper 23, and a pedestal of the fixed arc contactor 3. The difference is that the elastic body C27 is installed between the movable shield 20 and the movable shield 20 (fixed side tip portion).

In the first embodiment, the movable shield 20 can freely move in the axial direction if there is a nozzle protrusion 21 between the movable side stopper 22 and the fixed side stopper 23.

On the other hand, in the closing operation, a very large acceleration may be generated, and the position of the movable shield 20 vibrates in the axial direction due to the collision between the nozzle protrusion 21 and the fixed side stopper 23, and the electric field between the poles is not stable. In some cases. In addition, the closing operation may be continuously performed, and the movable shield 20 may operate before the nozzle protrusion 21 comes into contact with the fixed side stopper 23.

According to this embodiment, the movable shield 20 can have a holding force on the fixed side (left side in the drawing), and may not be operated until the nozzle protrusion 21 comes into contact with the fixed side stopper 23 during the closing operation. it can.

Further, during the closing operation, the movable shield 20 can relax the electric field of the movable shield 20 faster by receiving a force on the fixed side, and can prevent dielectric breakdown to the movable shield 20 due to the closing surge. it can.

Further, the elastic body A25 absorbs the impact during the closing operation, and the stress on the nozzle protrusion 21 can be reduced.

FIG. 8 is a cross-sectional view illustrating a schematic configuration during the shutoff operation of the gas circuit breaker of the third embodiment.

The gas circuit breaker described in this embodiment has an elastic body B26 between the nozzle protrusion 21 and the movable side stopper 22 and a pedestal of the fixed arc contactor 3 as compared with the gas circuit breaker described in the first embodiment. The difference is that the elastic body C27 is installed between the movable shield 20 and the movable shield 20 (fixed side tip portion).

In the first embodiment, the movable shield 20 can freely move in the axial direction if there is a nozzle protrusion 21 between the movable side stopper 22 and the fixed side stopper 23.

On the other hand, in the cutoff operation, a very large acceleration may be generated, and the position of the movable shield 20 vibrates in the axial direction due to the collision between the nozzle protrusion 21 and the movable side stopper 22, and the electric field between the poles is not stable. In some cases. Further, the shutoff operation may be continuously performed, and the movable shield 20 may operate before the nozzle protrusion 21 comes into contact with the movable stopper 22.

According to this embodiment, the movable shield 20 can have a holding force on the movable side (right side in the drawing), and during the shutoff operation, the movable shield 20 may not be operated until the nozzle protrusion 21 comes into contact with the movable side stopper 22. it can.

Further, the elastic body B26 absorbs the impact during the shutoff operation, and the stress on the nozzle protrusion 21 can be reduced.

FIG. 9 is a cross-sectional view illustrating a schematic configuration during the shutoff operation of the gas circuit breaker of the fourth embodiment.

The gas circuit breaker described in this embodiment has an elastic body A25 between the nozzle protrusion 21 and the fixed side stopper 23, and the nozzle protrusion 21 and the movable side, as compared with the gas circuit breaker described in the first embodiment. The difference is that the elastic body B26 is installed between the stopper 22 and the elastic body C27 is installed between the pedestal of the fixed arc contact 3 and the movable shield 20 (fixed side tip portion).

According to this embodiment, the movable shield 20 can apply a force in both the movable side and the fixed side, and can assist the movement of the movable shield 20 during the shutoff operation and the closing operation, and the nozzle. The stress on the protrusion 21 can be reduced.

Further, it is possible to have a holding force in both the movable side and the fixed side, and it is also possible to prevent the movable shield 20 from operating unnecessarily due to vibration accompanying the operation.

According to the present embodiment, as in the second or third embodiment, the operation of the movable shield 20 against vibration can be stabilized, and the impact during the shutoff operation or the closing operation is transmitted by the elastic body A25 and the elastic body B26. It can be absorbed and the stress on the nozzle protrusion 21 can be reduced.

Further, the elastic body A, the elastic body B, and the elastic body C can hold the position of the movable shield 20, and can be applied to, for example, a vertical gas circuit breaker.

The present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

1 ... Gas tank, 2 ... Movable side arc contactor, 3 ... Fixed side arc contactor, 4 ... Fixed side main contactor, 5 ... Movable side main contactor, 6 ... Hollow rod, 7 ... Puffer piston, 8 ... Puffer cylinder , 9 ... Puffer chamber, 10 ... Insulated nozzle, 11 ... Movable cover, 12 ... Shield, 13 ... Fixed side exhaust stack, 14 ... High electric field part, 15 ... Electric field shield, 16 ... High electric field part, 20 ... Movable shield, 21 ... piston protrusion, 22 ... movable side stopper, 23 ... fixed side stopper, 24 ... nozzle guide, 25 ... elastic body A, 26 ... elastic body B, 27 ... elastic body C.

Claims (7)

A gas tank filled with an insulating gas, a movable side main contactor housed inside the gas tank, a fixed side main contactor installed so as to be detachable from the movable side main contactor, and the fixed side main contact. Has an insulating nozzle installed on the inner circumference side of the child,
A gas circuit breaker having a nozzle guide installed in a tubular shape inside the fixed-side main contactor and a movable shield that slides on the inner peripheral side of the nozzle guide. The gas circuit breaker according to claim 1, wherein the movable shield has a movable side stopper and a fixed side stopper on the inner peripheral side thereof. The gas circuit breaker according to claim 1, wherein the insulating nozzle has a nozzle protrusion on the outer peripheral side thereof. The movable shield has a movable side stopper and a fixed side stopper on the inner peripheral side thereof, the insulating nozzle has a nozzle protrusion on the outer peripheral side thereof, and the nozzle protrusion has the movable side stopper and the said The gas circuit breaker according to claim 1, wherein the gas circuit breaker moves between the fixed side stopper and the fixed side stopper. The gas circuit breaker according to claim 4, wherein an elastic body is installed between the movable side stopper and the nozzle protrusion. The gas circuit breaker according to claim 4, wherein an elastic body is installed between the fixed-side stopper and the nozzle protrusion. The gas circuit breaker according to claim 4, wherein an elastic body is installed between the movable side stopper and the nozzle protrusion, and between the fixed side stopper and the nozzle protrusion.

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