JPH09182262A - Gas-insulated electric apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized highly reliable gas-insulated electric apparatus wherein, despite of its improved dielectric strength, its manufacturing cost can be reduced by its simple structure and no long term is required until its operation is started after its setting. SOLUTION: An insulation gas is filled into the interior of a grounded tank 2 of an enclosed cylindrical metallic container. On the center axis of the interior of the grounded tank 2, a conductor 1 is held by insulation spacers 6. On the lower portion of the inner surface of the grounded tank 2, there is provided with a trapping apparatus 7 comprising a plurality of bar-form metallic structures 7a arranged in parallel with each other in the circumferential direction of the grounded tank 2 each of which is extended in the longitudinal direction of the grounded tank 2 and has a circular section. The predetermined places of the metallic structures 7a are welded fixedly to the grounded tank 2 to be connected electrically with it. When the radium of the section of each metallic structure 7a and the space between the adjacent ones are denoted respectively as r and P, the metallic structures 7a are arranged to satisfy the relation of P>=2.8.r.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated electric device in which a conductive conductor is housed in a grounding tank filled with an insulating gas, and more particularly to a gas-insulated device for accumulating and capturing foreign matter such as metal powder in the grounding tank. Regarding electric devices.

[0002]

2. Description of the Related Art A gas-insulated electric device has a conductor to which a high voltage is applied housed in a metal container. Since the conductor is protected from the influence of the external environment by the metal container, there is no danger of electric shock or fire. Few. Therefore, reliability and safety are high,
It is also environmentally friendly. An example of such a gas-insulated electric device that has been widely used in the past will be described below with reference to FIG. That is, in this gas-insulated electric device, the ground tank 2 made of aluminum or the like is used as the metal container. Ground tank 2
Is a closed cylindrical container, the inside of which is filled with an insulating gas. Inside the grounding tank 2, a conductor 1 to which a high voltage current is applied is provided.

The conductor 1 is supported by the trap device 4 on the central axis of the ground tank 2 so as to maintain insulation with the inner wall surface of the ground tank 2. The trap device 4 is composed of a mounting member 3, a ring 4A and a contactor 4B. The mounting member 3 is an insulating member having the conductor 1 inserted through the center thereof. The mounting member 3 is supported in the ring 4A by the legs protruding from its periphery,
The conductor 1 is held at a predetermined distance from the ring 4A. The ring 4A is a short tubular body made of metal, and a large number of slits 4D that are long in the circumferential direction are formed in parallel with each other in a part thereof. The ring 4A is supported in the ground tank 2 via the contactor 4B. This contact 4
B is a metal member that is in contact with the inner wall surface of the ground tank 2, and electrically connects the ring 4A and the ground tank 2. In addition, such a gas-insulated electric device is installed so that a portion where the slit 4D is formed is located below.

In the gas-insulated electric device as described above, a high voltage is applied to the conductor 1, but the conductor 1 is insulated and supported by the mounting member 3 while keeping a predetermined distance from the ring 4A and the inner wall of the ground tank 2. Therefore, it can be operated while maintaining high safety.

In the process of installing the gas-insulated electric device as described above, foreign matter such as metal powder may enter the ground tank 2. When a high voltage is applied to the conductor 1 with the foreign matter in the grounded tank 2 as described above, the foreign matter in the grounded tank 2 makes a jumping motion as if an insect bounces.

The action of such foreign matter will be described below.
That is, when a high voltage is applied to the conductor 1, the foreign matter in contact with the inner wall surface of the ground tank 2 is charged. At this time, since a strong electric field exists in the ground tank 2, buoyancy acts on the charged foreign matter and the foreign matter floats in the space inside the ground tank 2. The floating foreign matter receives an electrostatic force in the gas space due to its own electric charge, but in the case of an AC voltage, the polarity of the voltage is always reversed, so the electrostatic force acting on the foreign matter is canceled out. Therefore, the foreign matter receives a force only when it floats, and behaves almost like a parabolic motion and falls.
The foreign matter that has fallen is charged again when it touches the inner wall surface of the ground tank 2 and floats up in the space. When the foreign matter floats and distributes in the space between the conductor 1 and the ground tank 2 in this manner, the foreign substance may flash between the conductor 1 and the ground tank 2, and the dielectric strength of the gas-insulated electric device may decrease.

[0007] As described above, among the metallic foreign matters that affect the dielectric strength of the gas-insulated electric device, the shape of the most serious foreign matter has been found to be a slender needle shape. That is, the needle-shaped metallic foreign matter has a property of standing up in the direction of the electric field due to a slight disturbance when a voltage is applied and the electric field strength exceeds a specific value, and in this standing state, it is extremely easy to be charged. The once-charged metallic foreign matter floats along the direction of the electric field. The floating metallic foreign matter easily reaches the vicinity of the surface of the conductor 1 having a strong electric field strength, and since it has a property of always standing in the direction of the electric field, the probability of causing a flashover is increased. Then, the floating foreign matter receives an electrostatic force in the gas space due to its own charge, but in the case of an AC voltage, the polarity of the voltage is always reversed, so the electrostatic force acting on the foreign matter is canceled out. Therefore, the metallic foreign matter receives a force only when it floats, and the foreign matter falls in a behavior almost similar to a parabolic motion. When the fallen foreign matter touches the inner wall surface of the ground tank 2, it is charged again and floats in the space. However,
The force involved in re-floating is not only charged, but also greatly affected by the coefficient of repulsion generated when the metallic foreign matter vigorously collides with the inner surface of the grounded tank.

In order to deal with this, in one example of the above gas-insulated electric device, a process called "conditioning" is performed after the installation work is completed. “Conditioning” means that a rated voltage or a voltage lower than the rated voltage is applied between the conductor 1 and the ground tank 2 by an AC power source after the gas-insulated electric device is installed and before the use is started, and foreign matter is preliminarily stored in the trap device 4. It is a process of collecting and capturing in the gap 4C.

The process of capturing metallic foreign matter by such "conditioning" will be described below. That is,
A voltage is applied between the conductor 1 and the ground tank 2 using an AC power supply of a predetermined voltage. Then, the foreign matter in the ground tank 2 jumps in the ground tank 2 and moves in an arbitrary direction as described above. Then, as shown by the arrow in the figure, the foreign matter repeats the jumping motion to reach the slit 4D portion of the trap device 4, passes through the slit 4D, and falls into the gap 4C between the ring 4A and the ground tank 2. Since the ring 4A and the ground tank 2 are electrically connected by the contact 4B and have the same potential, the electric field strength in the gap 4C is extremely low. Therefore, the foreign matter does not float again, and the gap 4C
To stay in. In this way, many foreign matters in the ground tank 2 gradually gather in the gap 4C with the passage of time. Since the foreign matter once collected in the gap 4C is captured by gravity, it stays as it is and is not scattered again in the ground tank 2.

[0010]

However, the above-mentioned conventional gas-insulated electric device has the following problems. That is, in the gas-insulated electric device, the trap device 4 having a complicated structure needs to be provided at every predetermined distance, which leads to an increase in manufacturing cost. In addition, since the conditioning process had to be performed after the installation work, it took a considerable time from the installation to the actual start of operation. Furthermore, the gap 4 of the trap device 4 in which foreign matter is accumulated and captured
Since C needs to be large, there is a problem that the outer diameter of the grounding tank 2 becomes large accordingly.

The present invention has been proposed in order to solve the problems of the prior art as described above, and an object thereof is to improve the dielectric strength and reduce the manufacturing cost with a simple structure, and to improve the after-installation. It is an object of the present invention to provide a small-sized and highly reliable gas-insulated electric device that does not require a long period of time from the start of operation to the start of operation.

[0012]

In order to achieve the above object, the invention according to claim 1 is provided with a grounding tank which is a closed metal container filled with an insulating gas, and a conducting conductor to which a high voltage is applied. In a gas-insulated electric device in which the above is insulated and arranged inside the ground tank, a rod-shaped metal structure having a circular end section is electrically connected to the ground tank.
It is characterized by being fixed to the inner surface of the ground tank by welding.

In the invention described in claim 1 as described above, where the circular outer surface of the rod-shaped metal structure and the inner surface of the grounding tank, which can be said to be substantially flat, are in contact, a wedge-shaped wedge gap is formed by the arc and the flat surface. Are formed. The needle-shaped metallic foreign matter that most seriously affects the dielectric strength of the gas-insulated electric device was accelerated by the electric field, collided with the ground tank while standing in the direction of the electric field, and then slept from the standing state by the wedge gap. It becomes a state. The needle-shaped metallic foreign matter once laid down on the side emits a charged electric charge and is shielded by the rod-shaped metallic structure to lie in a place where the electric field is weak, so that it is not charged with static electricity again. Therefore, it does not float again and stays in the valley formed by the metal having a circular cross section and the grounding tank.

According to a second aspect of the present invention, in the gas-insulated electric device according to the first aspect, the ground tank has a cylindrical shape,
The current-carrying conductors are arranged on the central axis of the ground tank, and the plurality of rod-shaped metal structures are arranged in parallel with each other along a part or all of the circumference of the inner surface of the ground tank at predetermined intervals. Is characterized by.

According to the second aspect of the invention as described above, since the rod-shaped metal structure can be manufactured by welding a plurality of metal structures in the ground tank, the structure is simple.

According to a third aspect of the present invention, in the gas-insulated electric device according to the first aspect, the ground tank has a cylindrical shape,
The current-carrying conductor is arranged on the central axis of the ground tank, the rod-shaped metal structure is formed into a ring shape along the circumference of the inner surface of the ground tank, and in the central axis direction of the ground tank, in parallel with each other. It is characterized in that a plurality of them are arranged at a predetermined interval.

According to the third aspect of the present invention as described above, since the ring-shaped rod-shaped metal structure can be manufactured by welding a plurality of metal structures in the grounded tank, the structure is simple.

According to a fourth aspect of the present invention, in the gas-insulated electric device according to the third aspect, the inner radius of the ground tank is R.
And the radius of the cross section of the end portion of the ring-shaped rod-shaped metal structure is r, and the predetermined interval of the ring-shaped rod-shaped metal structure is P, the relationship of P <r + r · (2R−r) is established. It is characterized by doing.

In the invention according to claim 4 as described above, since the predetermined interval P of the ring-shaped rod-shaped metal structure is a value satisfying the above formula, it is possible to weld the rod-shaped metal structure by any chance. Even if the rod-shaped metal structure is broken and mechanically fixed to the ground tank, the rod-shaped metal structure is not caught by the adjacent rod-shaped metal structure and falls.

According to a fifth aspect of the present invention, in the gas-insulated electric device according to the first aspect, the ground tank has a cylindrical shape,
The current-carrying conductor is arranged on the central axis of the grounding tank, the rod-shaped metal structure is formed into a spiral shape along the inner circumference of the grounding tank, and the grounding tank is arranged at a spiral pitch with a predetermined interval. It is characterized by being installed coaxially with the central axis of.

According to the invention described in claim 5, the structure can be simplified because the spiral rod-shaped metal structure can be manufactured by welding in the grounded tank.

According to a sixth aspect of the present invention, in the gas-insulated electric device according to any one of the second to fifth aspects, the radius of the end cross section of the rod-shaped metal structure is r, and the rod-shaped metal structure is Is defined as P, the relationship of P ≧ 2.8 · r is established.

In the above-mentioned invention according to claim 6, since the predetermined interval P of the rod-shaped metal structure is 2.8 · r or more, it is suitable for the size suitable for capturing the metallic foreign matter.

According to a seventh aspect of the present invention, in the gas-insulated electric device according to any one of the first to sixth aspects, a diameter of an end cross section of the rod metal structure is 5 mm or more. To do.

In the invention described in claim 7 as described above, since the diameter of the end cross section of the rod-shaped metal structure is 5 mm or more, the rod-shaped metal structure conforms to a size suitable for capturing needle-shaped metallic foreign matters.

According to an eighth aspect of the present invention, in the gas-insulated electric device according to any one of the first to seventh aspects, the inside of the rod-shaped metal structure is hollow, and a part of a circular cross section is formed. It is characterized in that a notch is formed.

In the above-mentioned invention according to claim 8, the needle-shaped metallic foreign matter flipped upward in the ground tank is also complemented by the notch provided in the rod-shaped metal structure.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a gas-insulated electric device of the present invention will be described below with reference to FIGS. The current-carrying conductors described in the claims are conductors, and the rod-shaped metal structure is a metal structure. The same members as those in the related art shown in FIG.

(1) First Embodiment One embodiment corresponding to the inventions described in claims 1, 2, 6, and 7 will be referred to as a first embodiment in FIGS. 4 will be described below. 1 is a side sectional view of the present embodiment, and FIG. 2 is a vertical sectional view showing details of the trap device according to the present embodiment. Further, FIG. 3 is a vertical cross-sectional view showing the moving action of the metallic foreign matter in the present embodiment, and FIG. 4 is a vertical cross-sectional view showing the diameter and installation interval of the metal structure of the present embodiment.

(Configuration) First, the configuration of the present embodiment will be described. That is, as shown in FIG. 1, the conductor 1 is held by the insulating spacer 6 on the central axis of the ground tank 2. The insulating spacer 6 is an insulating member. The conductor 1 is inserted through the center of the insulating spacer 6 and is supported on the inner wall of the ground tank 2 by the legs protruding from the periphery.

A trap device 7 is arranged below the inner surface of the ground tank 2. This trap device 7
As shown in FIG. 2, a plurality of rod-shaped metal structures 7a in the longitudinal direction of the ground tank 2 are arranged in parallel with each other in the circumferential direction of the ground tank 2. Each metal structure 7a has a circular cross section, and its interval is constant. The ground tank 2 and the metal structure 7a are electrically connected by welding and fixing a predetermined portion of the rod-shaped metal structure 7a to the ground tank 2. This metal structure 7
The diameter of the circle in the cross section of a is 5 mm or more. If the radius of the cross section of the metal structure 7a is r and the interval between adjacent metal structures 7a is P, the metal structure 7a is P
It is arranged so that a relationship of ≧ 2.8 · r is established.

(Operation) The operation of the present embodiment having the above configuration is as follows. That is, as shown in FIG. 3, at the location where the circular outer surface of the metal structure 7a and the substantially flat inner wall surface of the ground metal tank 2 are in contact with each other, a wedge-shaped wedge gap is formed by the arc and the flat surface. ing. Then, when a high voltage is applied to the conductor 1, the needle-shaped foreign metal 5a collides with the grounded metal tank 2 in a state of being accelerated by the electric field and standing in the direction of the electric field, as shown by 8 in the figure. , The wedge gap causes the person to fall asleep from the standing state. The metal foreign matter 5a lying sideways once releases the charged electric charge, and the metal structure 7
Since it is shielded by a and lies in a place where the electric field is weak,
It will not be charged with static electricity again. Therefore, it does not float again and stays in the valley formed by the metal structure 7 a and the ground tank 2.

Here, the capture efficiency of the needle-shaped foreign metal 5a changes depending on the relationship among the radius r of the cross section of the metal structure 7a, the installation interval P of the metal structure 7a, and the length l of the foreign metal. Therefore, if the length l is determined, the optimum r and P corresponding to this can be calculated.

Therefore, the length l of the metallic foreign matter to be targeted will be described first. That is, the needle-shaped metallic foreign matter having a length 1 of 5 mm or less does not have an influence enough to extremely reduce the dielectric strength of the gas insulated electric device. Therefore, the needle-like metallic foreign matter to be captured should have a length l of 5 mm or more.

Next, the optimum value of the radius r of the metal structure 7a will be described. That is, the radius r is 2 · r is l
When larger, the effect of trapping the metallic foreign matter 5a appears. 2.
Since r corresponds to the diameter of the circle of the cross section of the metal structure 7a,
From the optimum value of the length l of 5 mm or more, the metal structure 7a
The optimum value of r is such that the diameter of the circle of the section is 5 mm or more.

Further, the optimum value of the installation interval P of the metal structures 7a will be described. That is, if the installation interval P is too small, the other end of the needle-shaped foreign metal 5a is caught on the surface of the metal structure 7a, and the effect of lying down from the standing state is reduced. In order to sufficiently secure the action of the metal foreign matter 5a lying down, as shown in FIG. 4, the length of the tangent line of the cross-section circle of the adjacent metal structures 7a is set to the length l of the metal foreign matter 5a. The above may be done. Therefore, when calculated under these conditions, the minimum limit of the installation interval P is P ≧
An expression of 2.8 · r is obtained.

If the installation interval P becomes too large,
The effect of capturing metallic foreign matters is reduced. More specifically, the trapping effect gradually decreases when the installation interval P exceeds 4 · r. On the other hand, the larger P has the advantage of lower material cost. For this reason, the extent to which the installation interval P is widened depends on whether an inexpensive trap device is used or a high trapping effect is obtained.

In the present embodiment, the diameter 2 · r of the circle of the cross section of the rod-shaped metal structure 7a is 5 mm or more, and the installation interval P is 2.8 · r or more. It is suitable for the size suitable for capturing various metallic foreign substances.

(Effects) The effects of the present embodiment as described above are as follows. That is, the trap device 7 can be manufactured only by welding the rod-shaped metal structure 7a to the inner wall of the ground tank 2, so that the structure is simple and can be easily manufactured by a commercially available extremely inexpensive material. The efficiency of trapping the metallic foreign matter is good because the diameter and the installation interval of the metal structure 7a of the trap device 7 conform to the above-mentioned optimum dimensions. Therefore, it is possible to easily and inexpensively construct a gas-insulated electric device having a simple structure and excellent dielectric strength. In particular, in this case, the present embodiment can be configured only by adding the trap device 7 to the conventional gas-insulated electric device that does not include the trap device 7 without changing the basic structure thereof. It is even easier and cheaper to manufacture.

Since the ground tank 2 is not increased in size by providing the trap device 7, a compact gas-insulated electric device can be constructed. In particular, by simply adapting the diameter and the installation interval of the metal structure 7a to the optimum size, it becomes possible to efficiently supplement the metal foreign matter 5a. Therefore, the needle-shaped metal foreign matter 5a is captured in the size of the ground tank 2. This is advantageous for downsizing gas-insulated electric devices, as there is no need to provide a space in consideration of the space.

The metal structure 7a is the ground tank 2
Since it is fixed by welding inside, it does not move inside when the device is installed or when voltage is applied, and it is stable, so the reliability of the device is high.

Furthermore, since the action of capturing the metallic foreign matter 5a is performed during normal operation, it is not necessary to perform conditioning treatment, and operation can be started immediately after installation. In particular, the trapping action is physically performed by the valley formed by the metal structure 7a and the grounded tank 2 in addition to the suppression of the levitation due to the fact that the metallic foreign matter 5a does not become statically charged again. The effect of preventing the decrease in yield strength becomes more certain.

(2) Second Embodiment Claim 1, Claim 3, Claim 4, Claim 6 and Claim 7
One embodiment corresponding to the described invention will be described below as a second embodiment with reference to FIGS. 5, 6 and 7. 5 is a side sectional view of the present embodiment, and FIG. 6 is a vertical sectional view showing details of the ring-shaped metal structure in the present embodiment. Further, FIG. 7 is a side cross-sectional view showing a state in which the welding of one metal structure is cut and tilted.

(Configuration) First, the configuration of the present embodiment will be described. That is, as shown in FIG. 5, a plurality of ring-shaped metal structures 9 a along the circumference of the inner wall of the ground tank 2 are arranged at predetermined intervals in the central axis direction of the ground tank 2.
Each metal structure 9a has a circular cross section, and is electrically connected to the ground tank 2 by welding and fixing a predetermined portion to the inner surface of the ground tank 2. here,
The diameter of the circle of the cross section of the metal structure 9a is 5 mm or more.
If the radius of the cross section of the metal structure 9a is r and the interval between the adjacent metal structures 9a is P, P ≧ 2.
If the inner radius of the ground tank 2 is R, then P <r + r · (2R−
It is arranged so that the relationship of r) is established.

(Operation) The operation of the present embodiment having the above configuration is as follows. That is, since the metal structure 9a in the present embodiment has a circular cross section,
A wedge gap is formed at a portion where the outer surface of the metal structure 9a and the inner wall surface of the ground tank 2 are in contact with each other. Therefore, when a high voltage is applied to the conductor 1, the metallic foreign matter 5a is removed from the metallic structure 9 by the same action as in the first embodiment.
It stays in the valley formed by a and the ground tank 2.

The ring-shaped metal structure 9a has a cross-sectional circle diameter of 5 mm or more, and when the cross-sectional radius r and the installation interval are P, the relationship of P ≧ 2.8 · r is established. It is arranged. Therefore, it is suitable for the size suitable for capturing the metallic foreign matter.

Further, the metal structure 9a is the ground tank 2
Since the inner radius of R is R, the arrangement is such that the relationship of P <r + r.multidot. (2R-r) is established. Therefore, as shown in FIG. Even if the mechanical fixing to the tank 2 is released, the metal structure 9a is not caught by the adjacent metal structure 9a and falls.

(Effect) The effects of the present embodiment as described above are as follows. That is, the present embodiment can be manufactured by simply welding the metal structure 9a into the ground tank 2.
Only by adapting the cross-sectional diameter and the installation interval of the metal structure 9a to the above-mentioned optimum dimension, the efficiency of capturing the metal foreign matter 5a can be improved. Therefore, similarly to the first embodiment, the gas-insulated electric device having excellent dielectric strength can be easily constructed at low cost. In particular, since the present embodiment can be configured only by adding the metal structure 9a to the conventional gas-insulated electric device that does not include the metal structure 9a, without changing the basic structure thereof. In such a case, its production becomes much easier and at a lower cost.

Since the ground tank 2 does not increase in size due to the provision of the metal structure 9a, a compact gas-insulated electric device can be constructed. In particular, since it is possible to efficiently supplement the metal foreign matter 5a by simply adjusting the cross-sectional diameter and the installation interval of the metal structure 9a to the optimum dimensions,
It is not necessary to allow the dimension of the grounding tank 2 to have a margin in consideration of the space for capturing the needle-shaped foreign metal 5a, which is advantageous for downsizing the gas-insulated electric device.

Since the metal structure 9a is fixed in the grounded tank 2 by welding, it does not move inside when the device is installed or when voltage is applied, and is stable, so that the reliability of the device is high. Even if the metal structure 9a is welded off, it will not be caught by the adjacent metal structure 9a and fall down, so that the reliability of the gas insulated electric device can be further improved.

Furthermore, since the action of capturing the metallic foreign matter 5a is performed during normal operation, it is not necessary to perform conditioning treatment, and operation can be started immediately after installation. In particular, the trapping action is performed physically by the valley formed by the metal structure 9a and the ground tank 2 in addition to suppressing the floating of the foreign metal 5a that is not charged with static electricity again. The effect of preventing the decrease in yield strength becomes more certain.

(3) Third Embodiment One embodiment corresponding to the inventions of claim 1, claim 5, claim 6 and claim 7 is a third embodiment according to FIG. This will be described below. Note that FIG. 8 is a side sectional view showing details of the spiral metal structure in the present embodiment.

(Configuration) First, the configuration of the present embodiment will be described. That is, the spiral metal structure 9b along the inner surface of the ground tank 2 is installed coaxially with the central axis of the ground tank 2. The cross section of this metal structure 9b is circular,
It is electrically connected to the grounded tank 2 by fixing a predetermined portion by welding. Here, the diameter of the circle of the cross section of the metal structure 9b is 5 mm or more. The metal structure 9b is arranged so that the relation of P ≧ 2.8 · r is established, where r is the radius of its cross section and P is the pitch of the helix.

(Operation) The operation of the present embodiment having the above-mentioned structure is as follows. That is, since the metal structure 9b in the present embodiment has a circular cross section,
A wedge gap is formed at a portion where the outer surface of the metal structure 9b and the inner wall surface of the ground tank 2 are in contact with each other. Therefore, when a high voltage is applied to the conductor 1, the foreign metal 5a stays in the valley formed by the metal structure 9b and the ground tank 2 as in the first embodiment.

The spiral metal structure 9b has a circular cross section with a diameter of 5 mm or more. If the radius of the cross section is r and the pitch of the spiral is P, the relation of P ≧ 2.8 · r is established. It is located in. Therefore, it is suitable for the size suitable for capturing the metallic foreign matter. Further, the metal structure 9b
Since is integrated in a spiral shape, the position in the ground tank 2 does not change even if the welding at some point is broken.

(Effects) The effects of the present embodiment as described above are as follows. That is, the metal structure 9b can be constructed by simply welding it into the grounded tank 2, and the metal structure 9b can be formed.
It is possible to improve the efficiency of capturing the metallic foreign matter 5a only by adapting the cross-sectional diameter and the installation interval of the above to the above-mentioned optimum dimensions. Therefore, similarly to the first embodiment, the gas-insulated electric device having excellent dielectric strength can be easily constructed at low cost. In particular, since the present embodiment can be configured only by adding the metal structure 9b to the conventional gas-insulated electric device that does not include the metal structure 9b, without changing the basic structure thereof, In such a case, its production becomes much easier and at a lower cost.

Since the size of the ground tank 2 does not increase due to the provision of the metal structure 9b, a compact gas-insulated electric device can be constructed. In particular, since it is possible to efficiently supplement the metal foreign matter 5a by simply adjusting the cross-sectional diameter and the installation interval of the metal structure 9b to the optimum dimensions,
It is not necessary to allow the dimension of the grounding tank 2 to have a margin in consideration of the space for capturing the needle-shaped foreign metal 5a, which is advantageous for downsizing the gas-insulated electric device.

Since the metal structure 9b is fixed in the grounded tank 2 by welding, it does not move inside when the device is installed or when a voltage is applied and is stable, so that the reliability of the device is high. Even if a part of the metal structure 9b is cut off, the position of the metal structure 9b does not change because the metal structure 9b is spirally integrated, and the reliability of the gas-insulated electric device is further improved. It can be done.
This means that the reliability does not deteriorate so much even if the number of welded portions is reduced, so that it is possible to reduce the manufacturing process by omitting the welded portions.

Furthermore, since the action of capturing the metallic foreign matter 5a is performed during normal operation, it is not necessary to perform conditioning treatment, and operation can be started immediately after installation. In particular, the trapping action is performed physically by the valley formed by the metal structure 9b and the ground tank 2 in addition to the floating suppression due to the metal foreign matter 5a not being charged with static electricity again, and therefore the insulation of the gas-insulated electric device is achieved. The effect of preventing the decrease in yield strength becomes more certain.

(4) Other Embodiments The present invention is not limited to the above embodiments, and the shape, material, size, etc. of each member can be changed as appropriate. For example, as one embodiment corresponding to the invention described in claim 10, a ring-shaped metal structure 9c having a circular cross section is provided along the inner surface of the ground tank 2 as in the second embodiment. It is also possible to construct a structure in which welding is installed at predetermined intervals. A part of the metal structure 9c,
A notch is formed in the ground tank 2 at a position corresponding to the upper side. With such a configuration, the same operation and effect as those of the above-described embodiment can be obtained, and the needle-shaped metallic foreign matter blown off above the ground tank 2 is effectively captured in the notch, so that the gas The effect of preventing a decrease in the dielectric strength of the insulated electric device becomes more reliable.

The number of metal structures 7a, 9a, 9c in the first, second and other embodiments and the number of spirals of the metal structure 9b in the third embodiment are the same as those of the ground tank 2. It can be freely increased or decreased according to size, manufacturing cost, etc.

[0062]

According to the present invention as described above, a rod-shaped metal structure having a circular end section is welded and fixed to the inner surface of the ground tank so as to be electrically connected to the ground tank. It is possible to provide a small-sized and highly reliable gas-insulated electric device that can reduce the manufacturing cost with a simple structure while improving the dielectric strength, does not require a long period of time from the installation to the start of operation.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a gas-insulated electric device according to a first embodiment of the present invention.

FIG. 2 is a radial cross-sectional view showing details of the trap device according to the embodiment of FIG.

FIG. 3 is a radial cross-sectional view showing the movement action of the metallic foreign matter in the embodiment of the present invention.

FIG. 4 is a radial cross-sectional view showing the diameter and the installation interval of the metal structure according to the embodiment of the present invention.

FIG. 5 is a side sectional view of a gas-insulated electric device according to a second embodiment of the present invention.

FIG. 6 is a side sectional view showing details of a ring-shaped metal structure according to the second embodiment of FIG.

FIG. 7 is a side cross-sectional view showing a state where the welding of one metal structure in FIG. 6 is cut and tilted.

FIG. 8 is a side sectional view showing details of a spiral metal structure according to a third embodiment of the present invention.

FIG. 9 is a side sectional view showing details of a hollow metal structure according to another embodiment of the present invention.

FIG. 10 is a side sectional view showing an example of a conventional gas-insulated electric device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductor 2 ... Grounding tank 3 ... Mounting member 4, 7 ... Trap device 4A ... Ring 4B ... Contact 4C ... Gap 4D ... Slit 5 ... Metal foreign material 5a ... Needle metal foreign material 6 ... Insulating spacer 7a, 9a, 9b, 9c ... Metal structure 8 ... Needle-shaped trace of foreign matter tip

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 000003078 Toshiba Corp., 72 Horikawa-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Hiroshi Murase 2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Stock company Toshiba Hamakawasaki In the factory (72) Kenichi Nojima Kenichi Nojima 2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Stock Company Toshiba Hamakawasaki Factory (72) Inventor Yoichi Hoshina 2-1-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Company Toshiba Hamakawasaki factory

Claims (8)

[Claims] 1. A gas-insulated electric device comprising a grounding tank, which is a closed metal container filled with insulating gas, in which a conducting conductor to which a high voltage is applied is insulated and arranged inside the grounding tank. A gas-insulated electric device, wherein a certain rod-shaped metal structure is fixed to an inner surface of the ground tank by welding so as to be electrically connected to the ground tank. 2. The grounding tank is cylindrical, the current-carrying conductor is arranged on the central axis of the grounding tank, and the plurality of rod-shaped metal structures are provided along a part or all of the circumference of the inner surface of the grounding tank. 2. The gas-insulated electric device according to claim 1, wherein the gas-insulated electric devices are arranged parallel to each other and at a predetermined interval. 3. The ground tank has a cylindrical shape, the current-carrying conductor is arranged on a central axis of the ground tank, and the rod-shaped metal structure has a ring shape along the inner surface of the ground tank. The gas-insulated electric device according to claim 1, wherein a plurality of gas-insulated electric devices are arranged in parallel with each other in a central axis direction of the grounded tank and at a predetermined interval. 4. The inner radius of the ground tank is R, and the radius of the end cross section of the ring-shaped rod-shaped metal structure is r.
The gas insulated electrical apparatus according to claim 3, wherein a relationship of P <r + r · (2R−r) is established, where P is a predetermined interval between the ring-shaped rod-shaped metal structures. 5. The grounding tank has a cylindrical shape, the conducting conductor is arranged on the central axis of the grounding tank, and the rod-shaped metal structure has a spiral shape along the inner circumference of the grounding tank. The gas-insulated electric device according to claim 1, wherein the gas-insulated electric device is installed coaxially with a central axis of the ground tank at a spiral pitch with a predetermined interval. 6. When the radius of the end cross section of the rod-shaped metal structure is r and the predetermined interval between the rod-shaped metal structures is P, the relationship of P ≧ 2.8 · r is established. The gas-insulated electric device according to any one of claims 2 to 5. 7. The gas insulated electric device according to claim 1, wherein the rod-shaped metal structure has a diameter of an end cross section of 5 mm or more. 8. The inside of the rod-shaped metal structure is hollow,
The gas insulated electric device according to any one of claims 1 to 7, wherein a notch is formed in a part of a circular shape of the cross section.