JPH03269922A - Gas insulation grounding switch - Google Patents

Abstract

PURPOSE:To enhance short circuit closing performance and induced current cutting-off performance without changing a size of an equipment as a whole so as to improve reliability by forming a diameter of a tip end of a movable contact larger than those of other portions, and boring a gas communicating hole. CONSTITUTION:At the time of short circuit closing, a movable rod 5 approaches a stationary contact portion 2, and an arc 12 is generated between an arc resistant metal 5a and a shield 8 on a stationary side. When the arc 12 is moved in an arc resistant metal 7a of a contact 7 on the stationary side, insulating gas contained inside the shield 8 is discharged from a gas communicating hole 14 around the contact 7, to thus preventing a drop in closing speed, and the metal 5a is brought into contact with the contact 7 so that the arc 12 can be extinguished. At the time of cutting off an induced current, the arc can be rapidly extinguished with a decrease in electric field of the metal 5a in a process contrary to that at the time of short circuit closing. Moreover, during cutting off the induced current, insulating gas flows into the shield 8 through the communicating hole 14 to blow an arc column, thereby further enhancing arc extinguishing performance.

Description

[Detailed description of the invention] Purpose of invention] (Industrial application field) The present invention relates to gas insulated earthing switches.

(Prior Art) In recent years, as the demand for electric power has increased, the capacity of switches has been increasing. Generally, the general structure of a gas insulated earthing switch is
The configuration is as shown in the figure. That is, a fixed contact part 2 and a movable contact part 3 are disposed facing each other in a container 1 filled with an insulating gas such as SF or gas. Then, the operating mechanism section 4 fixed outside the container 1 is driven to move the movable rod 5 toward and away from the two contact sections 23, thereby opening and closing the earthing switch.

Here, the configuration of a contact portion of a conventional gas insulated grounding switch will be explained using FIG. 6. In other words, the fixed contact part 2 includes a contact base 6 fixed to the center conductor 20, and a fixed side arranged in a cylindrical shape on the movable contact part 3 side of the contact base 6, with an arc-resistant metal 7a fixed to the tip. contactor 7;
A cylindrical fixed-side shield 8 is provided on the movable contact portion 3 side of the contact base 6 so as to surround the fixed-side contact 7.

On the other hand, the movable contact portion 3 includes a contact base fixed to the container 1, a movable contact 10 arranged in a cylindrical shape on the fixed contact portion 2 side of the contact base 9, and the movable contact 1.
a movable rod 5 that is slidably inserted into the inside of the 0 and has an arc-proof metal 5a fixed to its tip and can move toward and away from the fixed contact 7; and a movable shield that is arranged to surround the movable contact 10. 11. The movable contact portion 3 is grounded to the container 1 by a grounding plate 13 .

In this gas-insulated earthing switch, when the switch is tripped from the closed state shown in FIG. 6 (when the induced current is cut off), the movable rod 5 separates from the stationary contact 7 as shown in FIG. 7. At this time,
A potential difference occurs between the arc-resistant metal 5a of the movable rod 5 and the arc-resistant metal 7a of the stationary contact 7, and an arc 12 is generated.

Further, as the bow removal progresses and the movable contact 5 is sufficiently separated from the fixed contact 7 and the arc current becomes 0, the arc 12 is extinguished and the induced current interruption is completed.

Furthermore, when the earthing switch is short-circuited, the movable rod 5 moves toward the fixed contact portion 2, and the electric field at the tip of the movable rod 5 increases until dielectric breakdown occurs. An arc 12 is generated between the arc-resistant metal 5a at the tip and the arc-resistant metal 7a of the stationary side contactor 7. At this time, the pressure of the gas in the stationary side shield 8 is increased due to the injection of energy by the arc. Then, the movable rod 5 moves further upward and the closing operation is completed.

(Problem to be solved by the invention) By the way, in order to miniaturize the device as much as possible in such a conventional gas-insulated grounding switch, the diameter of the movable rod 5 is made as thin as possible as long as the current carrying capacity is satisfied. was the norm. It is also known that the smaller the diameter of the movable rod 5, the higher the electric field at the tip of the movable rod 5, and the smaller the curvature of the tip, the higher the electric field becomes.

Therefore, when a short circuit occurs, the distance over which an arc is generated between the arc-resistant metal 5a of the movable rod 5 and the arc-resistant metal 7a of the stationary contact 7 becomes longer. In other words, since the duration of the arc 12 becomes longer, the movable rod 5, fixed side contactor 7, and fixed side shield 8 will be seriously damaged, and the gas pressure inside the fixed side shield 8 will expand significantly due to the heat of the arc 12. The pressure is increased, and the movable rod 5 is subjected to gas pressure in the opposite direction to the direction of injection, resulting in a vicious cycle in which the injection speed is significantly reduced and the duration of the arc 12 is further lengthened. Therefore, there was a high possibility that the movable rod 5 and the fixed contact 7 would be melted and the worst situation would occur, such as incomplete insertion.

Conversely, when the induced current is interrupted, the distance L (FIG. 7) for the arc 12 to extinguish becomes large, so the current value that can be interrupted becomes small, and the arc extinguishing performance becomes insufficient.

The present invention was made in order to solve the above-mentioned problems, and its purpose is to provide a highly reliable gas that improves both short-circuit closing performance and induced current breaking performance without increasing the size or complexity of the equipment configuration. The purpose of the present invention is to provide an insulated grounding switch.

[Structure of the Invention] (Means for Solving the Problem) A stationary contact fixed to the outer periphery of a center conductor disposed in an airtight container filled with insulating gas, and a contact/separator connected to the stationary contact. A gas insulated grounding switch comprising movable rods freely arranged to face each other, and a cylindrical fixed shield that is fixed to the device at one end around the fixed contact and opened at the other end, through which the movable rod can be inserted. In the device, only the tip of the movable rod is made larger in diameter than the other portions, and a gas circulation hole is provided in the tip, so that when the movable rod is short-circuited, the gas circulation hole closes the fixed side. The insulating gas in the shield is discharged into the container, and the insulating gas in the container is supplied into the stationary side shield through the gas flow hole with induced current interrupting property to bring the tip of the movable rod into contact with the stationary side. The feature is that the spray is applied to the arc that occurs between the child and the child.

(Function) According to the gas insulated earthing switch of the present invention, by making only the tip of the movable contact thicker, the electric field at the tip can be reduced, the duration of the arc can be shortened, and when a short circuit occurs, the electric field at the tip can be reduced. Expanded and pressurized gas in the stationary shield is released through the gas distribution hole, and when the current is cut off, a gas flow is sprayed onto the arc to improve arc extinguishing performance.

(Example) Hereinafter, an example of the gas insulated earthing switch of the present invention will be described based on FIGS. 1 to 4. Here, the same members as the conventional example shown in FIGS. are given the same reference numerals and their explanations will be omitted. 1 to 4 are sectional views of essential parts of the same embodiment.
3 and 3 show the short-circuit application process, and FIG. 4 shows the induced current cut-off process.

In this embodiment, as shown in FIG. 1, a fixed contact part 2 and a movable contact part 3 are housed in a container 1 filled with an insulating gas so as to be disposed facing each other on the same axis.

A movable rod 5 that reciprocates toward and away from the fixed contact portion 2 is arranged between both the contact portions 2 and 3.

The movable rod 5 has an arc-resistant metal 5a fixed to its tip with a large diameter and a gentle curvature. Further, the arc-resistant metal 5a is provided with an inverted Y-shaped gas circulation hole 4 in its longitudinal section, and this gas circulation hole 14 is used to allow insulating gas to flow from the tip of the arc-resistant metal 5a to the side surface when a short circuit is inserted. Insulating gas is supplied from inside the fixed contact 7 to the movable rod 5.
and when the current is cut off, the gas is released into the surroundings of the gas distribution hole 14.
This is to cause the insulating gas around the fixed contact portion 2 and the movable contact portion 3 to flow into the fixed side shield 8 and spray it onto the arc 12 generated between the arc-resistant metals 5a and 7a.

The operation of the gas insulated grounding switch of this embodiment having such a configuration will be described below. That is, when a short circuit is applied, the second
As shown in the figure, as the movable rod 5 approaches the fixed contact part 2, the electric field of the arc-resistant metal 5a at the tip of the movable rod 5 increases moment by moment, eventually leading to dielectric breakdown, and the electric field between the arc-resistant metal 5a and the fixed shield 8 increases. An arc 12 is generated in between, and the fixed contact part 2
A short circuit current of several tens of KA flows between the movable contact portion 3 and the movable contact portion 3.

Thereafter, when the movable rod 5 moves inside the fixed shield 8 as shown in FIG. 3 while the arc 12 continues, the arc 12 is generated between the arc-resistant metals 5a and 7a, and at this time The insulating gas inside is discharged from the inside of the fixed side contact 7 to around the movable contact 5 from the gas flow hole 14 of the arc-proof metal 5a as shown by the arrow 15a. When the arc-resistant metal 5a comes into contact with the fixed contact 7, a short circuit current flows between the movable rod 5 and the fixed contact 7, and the arc 12 is extinguished.

In this case, the diameter of the arc-resistant metal 5a of the movable rod 5 is increased and the curvature is made gentle to reduce the electric field at the tip.
As shown in Fig. 2, the arc 12 is not generated unless the arc-resistant metal 5a or the fixed contact part 2 are sufficiently close to each other (L in the conventional example).
The duration of the arc 12 is short (the L' dimension is smaller than that of the arc 12), and damage to the movable rod 5 and the fixed side contactor 7 is minimal.

Furthermore, the expansion and pressure increase of the gas pressure in the fixed contact part 2 due to the heat of the arc 12 is also caused by the insulating gas flowing through the gas distribution hole 14 bored in the arc-resistant metal 5a of the movable rod 5, as shown by the arrow 15a in FIG. Since it flows out to the outside, a significant drop in the input speed can be avoided.

Next, when the (induced) current is cut off, the state shown in FIG. 1 changes to the state shown in FIG. 4 by following the reverse process of arc generation at the time of short-circuiting. In this case as well, as mentioned above, the arc-resistant metal 5
By reducing the electric field a, the arc 12 can be detected quickly.

In addition, as shown in FIG. 4, during the cutoff, the gas flow hole 14 formed in the arc-proof metal 5a of the movable rod 5 allows air to flow from the outside of the fixed shield 8 to the inside of the fixed shield 8, as shown by an arrow 15b. Insulating gas flows in and arc 12
Arc-extinguishing performance can be further improved by spraying insulating gas onto the pillars.

In addition, the configuration of this embodiment is suitable for gas-insulated equipment that aims to be further downsized, since it is not necessary to increase the size of other parts of the equipment by only enlarging only the tip of the movable rod 5.

In the embodiments described above, there are three reasons why the insulating gas flows through the gas distribution hole 14 formed in the arc-resistant metal 5a as shown by the arrow 15a in FIG. 3 or the arrow 15b in FIG. 4. .

That is, the first reason is that the wind acts in the opposite direction to the moving direction of the movable rod 5. The second reason is that the short-circuit closing duty of the earthing switch is as large as several KA, and the induced current breaking duty is several orders of magnitude smaller, ranging from several +A to several hundred A.

The third reason is that although the inner diameter of the fixed shield 8 is the same as the conventional one, the outer diameter of the arc-resistant metal 5a at the tip of the movable rod 5 is larger than that of the conventional one.

[Effects of the Invention] As described above, according to the present invention, by making the diameter of the tip of the movable contact larger than other parts and drilling the arc circulation hole in the tip of the bracket, the dimensions of the entire device can be reduced. It is possible to provide a highly reliable gas insulated grounding switch with high short circuit closing performance and induced current breaking performance without any changes.

[Brief explanation of drawings]

1 to 4 are sectional views of essential parts of an embodiment of the gas insulated grounding switch according to the present invention, with FIG. 1 showing the closed state, and FIGS. 2 and 3 showing the closed state. Figure 4 is a diagram showing the short circuit closing process, Figure 5 is a schematic diagram of the conventional gas insulated earthing switch, and Figure 6 is the closing process of the gas insulated earthing switch shown in Figure 5. Fig. 7 is a sectional view of the main part at the time.
It is a figure which shows the short circuit closing process of the gas insulated earthing switch of a figure. DESCRIPTION OF SYMBOLS 1... Container, 2... Fixed contact part, 3... Movable contact part, 4... Operation mechanism part, 5... Movable rod, 5a.
- Arc-resistant metal, 6... Contactor base, 7... Fixed-side contact, 7a... Arc-resistant metal, 8... Fixed-side shield, 9
...Movable side base, 10...Movable side contact, ]1.
... Movable side shield, 12... Arc, 13... Ground plate, 14... Arc circulation hole, 15a... Gas flow when turned on, 15b... Gas flow when cut off.

Claims (1)

[Scope of Claims] A fixed contact fixed to the outer periphery of a center conductor disposed in a closed container filled with insulating gas, and a movable rod disposed opposite to the fixed contact so as to be able to move toward and away from the fixed contact. , a gas-insulated grounding switch including a cylindrical fixed-side shield having one end arranged and fixed around the fixed-side contact, the other end being open, and through which the movable rod can be inserted; The diameter of only the portion of the shield is made larger than that of the other portions, and a gas circulation hole is provided in the tip portion, and when the movable rod is short-circuited, the gas circulation hole allows the insulating gas in the fixed side shield to be transferred to the container. When the induced current is cut off, the insulating gas in the container is supplied into the stationary shield through the gas flow hole to prevent an arc occurring between the tip of the movable rod and the stationary contact. A gas insulated grounding switch characterized by being designed to spray air.