JPH07122165A - Gas insulating ground switch - Google Patents

Abstract

PURPOSE:To advance the downsizing in a ground switch with small current value and voltage value, and provide a gas insulating ground switch exhibiting excellent interrupting performance. CONSTITUTION:A movable contact 3 has a small hole 19 formed on the top end part and an air vent hole 9 formed on the base end part. A piston 8 movable in a cylinder part 17 is fixed to the base end part of the movable contact 3. A notch part 16 is formed on the cylinder part 17 corresponding to the stroke on and after about 80% of the standard stroke of the piston 8 from the opening point where the movable contact 3 is separated from a fixed contact part 2 to the end point where the interrupting operation is ended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated grounding switch which enhances arc extinguishing performance by utilizing a gas flow when shutting off.

[0002]

2. Description of the Related Art In recent years, substations are required to be compact and have a beautiful appearance. As a power device such as a grounding switch, a gas insulated type is often used. In addition, in recent years, the demand for electric power has been increasing, and thus the capacity of each device has been increasing, and along with this, the performance required for the device has also become more stringent.

For example, generally, a grounding switch used for a line is required to have a performance of cutting off an induced current induced in a power transmission line. In order to meet this requirement, among grounding switches of the voltage class such as 72KV / 168KV, which have a relatively small current value and voltage value, there are known parallel-breaking contacts that use arc-resistant metal for their contact parts. . In addition, a self-extinguishing contact is also proposed in which a nozzle is provided at the shield tip of the fixed contact portion to expand the gas in the fixed contact portion by the arc heat generated at the time of interruption and to interrupt the arc by the gas flow flowing out of the contact portion at the time of interruption. ing.

Further, in the voltage class of 300 KV or more, strict conditions are required from the beginning, so even in the earthing switch, gas is blown or sucked at the time of current interruption to forcibly generate a gas flow to generate an arc. The method of extinguishing is adopted. Here, a conventional example of a suction type grounding switch will be described with reference to FIG.

The grounding switch is housed in a tank 21 filled with an insulating gas, and a movable contact portion 22 and a fixed contact portion 23 are provided facing each other.
Of these, the movable contact portion 22 is provided with a cylindrical movable contact 24 that performs the closing and closing operations with respect to the fixed contact portion 23. An insulating gas is sucked into the movable contact 24 at the tip of the movable contact 24. Further, the fixed contact portion 23 is provided with a shield 26. According to such a grounding switch, since the movable contact 24 sucks the insulating gas into the inside when performing the breaking operation,
A gas stream can be generated, which can extinguish the arc.

[0006]

At the present time, there is an urgent need to improve the cut-off performance of the induced current with the increase in the capacity of electric power, and at the present time, the contact structure in the conventional earthing switch of the 2KV / 168KV voltage class or so. It is difficult to ensure excellent performance in the case of equipment size. Further, the grounding switch adopting the method of forcibly generating the gas flow requires a complicated piston structure at the contact portion or requires a larger drive mechanism, resulting in a larger device. Therefore, 7
It is not suitable to use a similar structure for a grounding switch having a voltage class of about 2 KV / 168 KV because of various drawbacks such as enlargement of equipment and enlargement of operating device.

The present invention has been proposed in view of such a situation, and an object thereof is to increase the size of the contact portion and the size of the equipment in a grounding switch whose current value and voltage value are small. It is an object of the present invention to provide a gas-insulated grounding switch that exhibits excellent breaking performance while suppressing a large output of an operating device.

[0008]

In order to achieve the above object, a gas insulated ground switch of the present invention is provided with a movable contact portion and a fixed contact portion facing each other, and the movable contact portion has a fixed contact portion. On the other hand, a cylindrical movable contactor that performs closing and making operations is provided, and a small diameter hole is formed on the tip end side of the movable contactor so that the insulating gas passes through the movable contactor.
Vent holes are formed on the base end side, the movable contact part is provided with a cylinder part, and the movable contactor has a base end part to which a piston movable within the cylinder part is fixed, so that the movable contact part has a movable contact part. Notches are formed in the cylinder part corresponding to the stroke of about 80% or more of the reference stroke of the piston from the opening point where the child separates from the fixed contact part to the end point where the shutoff operation ends. It is characterized in that a minute gap is formed between the movable contactor and the movable contactor.

[0009]

The operation of the present invention having the above construction is as follows. That is, when the piston in the cylinder moves toward the base end of the movable contact, the movable contact starts the breaking operation. At this time, since the moving contactor starts moving slowly, negative pressure is less likely to be generated by the piston and the cylinder portion. However, the tip of the movable contact is inside the fixed contact part with a minute gap. Therefore, the gas flow from the small diameter hole at the tip of the movable contact is less likely to occur, resulting in a negative pressure state higher than usual.

Then, when the movable contact is separated from the fixed contact portion, the gap between the movable contact and the fixed contact portion becomes large, so that gas flows from the outside into the small diameter hole at the tip of the movable contact, and The negative pressure decreases and the gas flow weakens. At this time, a large change occurs in the gas flow, so that conditions for easily interrupting a small induced current are set.

Further, as the speed of the movable contact increases, the negative pressure also increases, and the negative pressure and the operating force applied to the movable contact become close to a balanced state. In this state, a constant gas flow continues to be generated in the small-diameter hole at the tip of the movable contact, so that the arc is narrowed down in the small-diameter hole and exposed to new gas, so that the arc is easily extinguished. And current 0
It will be cut off near the point.

This state continues until about 80% of the reference stroke of the piston from the opening point where the movable contact is separated from the fixed contact portion to the end point where the breaking operation ends, but after 80%, Since the notch is formed in the cylinder part, negative pressure is not generated and the breaking ability is the same as that of the parallel cut. However, in order to determine whether the induced current cutoff performance is acceptable or not, it is generally required that the cutoff be completed within the 80% stroke, and therefore, there is no problem that the cutoff performance is deteriorated in the stroke after 80%. Rather, since the stroke after 80% is close to the end point of the breaking operation, conversely, if negative pressure continues to be generated in this region, considering that the operating force generally decreases on the end side, Incomplete operation may occur due to increased load at the end, which is not desirable for a device. On the other hand, according to the present invention, as described above, since the negative pressure is suppressed from being generated in the region close to the end point of the shutoff operation, it is possible to prevent the incomplete operation from occurring at the operation end.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. (Structure of this embodiment) This embodiment is a gas-insulated grounding switch in which three phases are collectively stored in a tank 1 filled with insulating gas as shown in FIGS. A fixed contact portion 2 and a movable contact portion 4 are provided in the tank 1 so as to face each other. The movable contact portion 4 is provided with a cylindrical movable contact 3 for performing closing and closing operations with respect to the fixed contact portion 2, and an opening / closing mechanism 5 and an insulating terminal 6 are attached.

FIG. 1 shows an enlarged view of the contact portion of this embodiment.
The movable contact part 4 is provided with an insulating shield 11, fingers 12 and a cylinder part 17. Of these, the cylinder portion 17 also serves as a conductor for passing a ground current. Further, the movable contactor 3 is provided in the cylinder portion 17 so as to be vertically movable.

The movable contact 3 is composed of a hollow cylindrical member, and the arc-resistant metal 10 is attached to the tip end side of the movable contact 3.
A piston 8 movable in the cylinder portion 17 is provided on the base end side.
Is fixed. A small diameter hole 1 is provided at the tip of the movable contactor 3.
9, a ventilation hole 9 is formed at the base end. The piston 8 is provided with a joint 7 for connecting the three phases.
A notch 16 is formed corresponding to about 80% or more of the stroke of the reference stroke of the piston 8 from the opening point where the movable contact 3 separates from the fixed contact portion 2 to the end point where the breaking operation ends. The notch 16 forms a large gap between the piston 8 and the cylinder 17.

The fixed contact portion 2 is fixed to the conductor 15 and is provided with an arc resistant finger 13 and a shield 18. The inner diameter of the shield 18 is set so that a minute gap is formed between the shield 18 and the movable contact 3. (Operation of this Embodiment) The state of negative pressure generated by the piston 8 and the cylinder portion 17 will be described with reference to FIGS. First, as the speed of the movable contactor 3 increases, the negative pressure generated in the cylinder portion 17 increases (FIG. 4). By the way, the speed of the movable contactor 3 increases with the operation of the equipment, but as the operation progresses, the speed of the movable contact 3 is constant, due to the load of the speed equipment, the negative pressure of the cylinder portion 17, and the limited operation force of the opening / closing mechanism 5. The equilibrium state is maintained at the end and the speed is finally reduced to 0 (Fig. 5). Therefore, the movable contactor 3 (or the piston 8)
The negative pressure generated in the cylinder portion 17 due to the operation of (1) starts to move and negative pressure is generated. However, the negative pressure is maintained in a substantially equilibrium state at a constant speed portion and changes to 0 as the speed decreases (FIG. 6).

Now, the operation of this embodiment will be described with reference to the graph of FIG. In this embodiment, the operation of the opening / closing mechanism 5 causes the piston 8 in the cylinder portion 17 to move toward the base end portion of the movable contactor 3 (upward in FIG. 1). As a result, the movable contactor 3 starts the breaking operation. At this time, the small-diameter hole 19 at the tip of the movable contactor 3 is substantially enclosed in the fixed contact portion 2 until the movable contactor 3 separates from the arc resistant finger 13 in the fixed contact portion 2, that is, up to the opening point. Therefore, although the speed of the movable contactor 3 is slow,
Since a small amount of gas does not enter from the small diameter hole 19, a relatively large negative pressure is generated.

However, since the gas easily flows into the fixed contact portion 2 suddenly after passing the opening point, a sudden gas inflow occurs from the small diameter hole 19, and the negative pressure temporarily decreases. After that, since the speed of the movable contactor 3 increases, the negative pressure also rises again, and the equilibrium state is continued. However, when the stroke of the piston from the opening point to the end point at which the breaking operation is ended, that is, the stroke up to 80% of the reference stroke (herein referred to as 80% stroke), the cutout portion 16 is formed in the cylinder portion 17. Therefore, the gas flows into the cylinder portion 17 all at once, and no load is generated. Here, from the viewpoint of the blocking performance of the induced current, first, immediately after passing through the opening point, a rapid gas flow occurs in the direction of flowing into the small diameter hole 19 and a relatively small induced current (arc 14 in FIG. 1). Is a condition in which it is easy to be shut off all at once. Here, even if the load is once reduced, the inflowing gas flow also fluctuates, and this also effectively acts on the interruption. After that, since the negative pressure increases, it is easy to cut off the induction current when the zero point has passed. Also, 80
After the% stroke, even if the negative pressure is maintained and the current is cut off, it does not fall within the pass / fail judgment of the induced current cutoff performance, so it is not effective as a product and there is no problem. Incidentally, since 80% stroke is close to the end point of the breaking operation, if negative pressure continues to be generated in this region, the operating force of the opening / closing mechanism 5 generally decreases on the end side of the breaking operation. , Incomplete operation may occur due to increased load at the operation end. On the other hand, in this embodiment, since the negative pressure is suppressed from being generated in the region close to the end point of the breaking operation, it is possible to prevent the incomplete operation from occurring at the operation end.

According to the present embodiment as described above, the induction current interruption has a good initial interruption performance in the vicinity of the opening point, and further, the gas flow due to the suction is continued until the stroke reaches 80% after the opening point, thereby passing the interruption. The interrupting performance can be maintained over the entire judgment range, and negative pressure is not generated after the 80% stroke so that the load does not become the load at the operation end. Therefore, the cause of incomplete operation due to the gas suction method can be eliminated, and the size is small. And, it was possible to secure a high interruption performance. (Other Embodiments) The present invention is not limited to the above embodiments, but may be an embodiment in which an insulating nozzle is provided at the shield tip of the fixed contact portion. The negative pressure at the time of interruption can be increased, and the initial interruption performance can be improved.

[0020]

As described above, according to the present invention, a stroke of about 80% or more of the reference stroke of the piston from the opening point where the movable contact is separated from the fixed contact portion to the end point where the breaking operation is ended. With a simple structure of forming a notch in the cylinder part that corresponds to the above, in a grounding switch with a small current value or voltage value, it is possible to suppress enlargement of the contact part, enlargement of the equipment and output of the operating device. While
It is possible to provide a gas-insulated grounding switch that exhibits excellent breaking performance.

[Brief description of drawings]

FIG. 1 is an enlarged front view of a contact portion of a grounding switch according to an embodiment of the present invention.

FIG. 2 is a front view showing the overall configuration of the earthing switch of this embodiment.

FIG. 3 is a side view showing the overall configuration of the earthing switch of this embodiment.

FIG. 4 is a graph showing the relationship between the speed of the movable contactor and the state of negative pressure generation.

FIG. 5 is a graph showing the relationship between the speed of the movable contactor and the elapsed operation time.

FIG. 6 is a graph showing the relationship between the elapsed operation time of the movable contactor and the negative pressure generation state.

FIG. 7 is a graph showing the relationship between the operation elapsed time of the movable contact and the negative pressure generation state in the present embodiment.

FIG. 8 is a structural diagram of a conventional suction type grounding switch.

[Explanation of symbols]

 1 ... Tank 2 ... Fixed contact part 3 ... Movable contactor 4 ... Movable contact part 5 ... Opening / closing mechanism 6 ... Insulation terminal 7 ... Joint 8 ... Piston 9 ... Vent hole 14 ... Arc 16 ... Notch part 17 ... Cylinder part 19 ... Small diameter hole

Claims (1)

[Claims] 1. A movable contact part and a fixed contact part are provided to face each other and are housed in a tank filled with an insulating gas, and the movable contact part is turned on and off with respect to the fixed contact part. A movable contact having a cylindrical shape for performing an operation is provided, and a small-diameter hole is provided on the distal end side of the movable contactor and a ventilation hole is provided on the proximal end side thereof so that the insulating gas can pass through the movable contactor. In the formed gas-insulated grounding switch, a cylinder part is provided in the movable contact part, a piston movable in the cylinder part is fixed to a base end part of the movable contact part, and the movable contact part is A notch is formed in the cylinder portion corresponding to a stroke of about 80% or more of the reference stroke of the piston from the open contact point separated from the fixed contact portion to the end point where the breaking operation is ended, and the fixed contact portion is further formed. Between parts and the movable contactor are turned herein, gas insulated earthing switch, wherein a small gap is formed.