JPH0984259A - Superconducting current limiter - Google Patents

Abstract

(57) [Abstract] [Problem] It was difficult to make a large-scale superconducting fault current limiter. In the tubular superconductor, the superconducting current did not flow in the circumferential direction. A superconducting fault current limiter (10) having a magnetic shield (11) and a coil (24) wound on the outside thereof.
The magnetic shield (11) has a hollow portion (1) extending substantially in the axial direction.
5) having two or more tubular bodies (16) forming substantially parallel to each other, each of the tubular bodies being capable of flowing a superconducting current in the circumferential direction, Moreover, it has a superconductor (16) having a tubular shape. The superconductor may be coated on a high resistance substrate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a superconducting fault current limiter in which two or more hollow portions extending in the axial direction are formed. When the superconductor becomes normal conduction, the impedance of the fault current limiter is large, and it limits the overcurrent flowing through the fault current limiter.

[0002]

2. Description of the Related Art Conventionally, development of a current limiting device for limiting a current in a transmission line system has been advanced. The current limiting device serves as a resistance when an overcurrent flows due to a short circuit, a lightning strike, or the like, and suppresses the overcurrent, thereby reducing the load on the circuit breaker, the transformer, and the like. There are various types of current limiting methods, but in recent years, a superconducting fault current limiter that limits a current using a superconductor has been proposed. This utilizes the magnetic shielding effect and magnetic flux switching effect of the superconductor.

In FIG. 5, a superconducting fault current limiter 60 has a magnetic shield 62, which is a superconductor, and a coil 63 around which a conducting wire is wound. The cooling container for cooling the superconductor is omitted. FIG. 5A shows a steady state in which the superconductor 62 is in the superconducting state. Normally, the coil 63, when energized, exhibits impedance due to its self-inductance. However, in the superconducting fault current limiter 60, the magnetic flux lines 65 do not enter the superconductor 62 itself due to the Meissner effect of the superconductor 62. Further, since the superconducting current also flows in the circumferential direction of the superconductor 62, the hollow portion 64 surrounded by the superconductor 62 is magnetically shielded, and the magnetic flux lines 65 are provided in the hollow portion 6.
Do not break into 4. Therefore, the magnetic flux line 65 penetrating the inside of the coil 63 is limited to the outside of the superconductor 62, the self-inductance of the coil 63 becomes very small, and the loss of normal transmission current is very small.

On the other hand, when an overcurrent is generated and a magnetic flux exceeding the critical magnetic field is generated, the superconducting state is quenched from the normal conducting state, and the superconductor 62 does not shield the magnetic field. FIG.
(B) shows the case of a normal conduction state. The magnetic flux lines 65 are the superconductor 62 itself and the hollow portion 6 surrounded by the superconductor 62.
4 penetrates axially and penetrates. Therefore, since the magnetic flux lines 65 are linked to the coil 63, inductance is generated in the coil and the overcurrent flowing through the coil is limited. This superconducting fault current limiter has an ON-OFF control switch function. On the other hand, Japanese Patent Application No. 4-74639 describes a superconducting fault current limiter capable of adjusting the current limiting action according to the magnitude of the overcurrent flowing through the external coil.

[0005]

In the superconducting fault current limiter,
It is desired that the inductance changes greatly. For that purpose, it is necessary to increase the size of the superconductor. However, it is technically difficult to increase the size of the tubular superconductor. For example, when a cylindrical ceramic molded body having a diameter of about 1 meter is sintered, cracks and the like are likely to occur due to temperature changes during sintering. Moreover, the electric furnace for sintering becomes large, and it becomes difficult to control the temperature. Therefore, it has been proposed to combine a small-sized superconductor and use it in a superconducting fault current limiter. Japanese Laid-Open Patent Publication No. 5-145128 discloses a superconducting cylinder in which small superconducting cylinders are laminated in the axial direction, and a superconducting cylinder in which axially long columnar bodies are combined in the radial direction to form a side wall portion surrounding a hollow portion. Describe the cylinder. US Patent 5,
FIG. 8 of No. 334, 964 forms a superconducting cylinder that forms a side wall portion that surrounds the hollow portion by combining columnar bodies that are long in the axial direction in the radial direction.

However, in JP-A-5-145128 and US Pat. No. 5,334,964, each columnar body is a solid body and is not a hollow body. In addition, the superconducting current is
Although it flows inside each columnar body, it does not flow from one columnar body to an adjacent columnar body because it is blocked by grain boundaries. That is, the superconducting current cannot flow in the circumferential direction over the entire tubular body, the magnetic field in the hollow portion surrounded by the tubular body is not shielded, and the magnetic flux lines can penetrate the hollow portion in the axial direction. This is not preferable because the inductance increases during steady state when the tubular body is in the superconducting state. Also, when the superconducting state is changed to the normal conducting state, the magnetic flux lines will newly penetrate only the cylinder itself, that is, the side wall part itself.
The increase in inductance, that is, the current limiting effect is limited.

[0007]

Therefore, an object of the present invention is to solve the above problems. That is, according to the present invention, in a superconducting fault current limiter having a magnetic shield and a coil wound on the outside of the magnetic shield, the magnetic shield is a cylinder forming a hollow portion extending substantially in the axial direction. Body 2
As described above, the tubular bodies are arranged substantially parallel to each other, and each of the tubular bodies has a superconductor having a tubular shape and capable of flowing a superconducting current in the circumferential direction. A superconducting fault current limiter is provided. Further, in the present invention, it is preferable that each of the cylindrical bodies has a high-resistance base having a cylindrical shape, and the superconductor covers the outer surface or the inner surface of the high-resistance base.

Further, it is preferable that the magnetic shield has a tubular outer wall portion, the coil is wound outside the outer wall portion, and the tubular body is combined to form the outer wall portion. . Furthermore, it is preferable that there is substantially no gap between the adjacent cylinders. Furthermore, it is preferable that the thickness of the superconductor is substantially constant.

In the present invention, the two or more cylinders are arranged substantially parallel to each other. Here, when two or more cylinders are “parallel”, it does not include that the two or more cylinders share each other's axis. That is, “two or more cylinders are“ parallel ”” means that the two or more cylinders penetrate a virtual plane that is perpendicular to the axial direction. Also, being “substantially” parallel means that the axial directions need not be completely parallel. In the present invention, each of the cylinders is
It has a tubular superconductor. In the present specification, the “superconductor” refers to a tangible substance whose electric resistance substantially disappears when cooled to a critical temperature or lower. Generally,
A superconductor is not superconducting at room temperature but has electric resistance.

In the present invention, the superconductor is capable of flowing the superconducting current in the circumferential direction. Thus, when the superconducting fault current limiter of the present invention is in the superconducting state, the magnetic flux lines cannot penetrate not only each superconductor but also the hollow part surrounded by each superconductor. . Further, it is easier to form two or more small superconductors than to form one large superconductor. Such a superconductor can be obtained by, for example, integrally forming. Forming integrally means, for example,
It can be obtained by forming a compact containing a superconducting oxide and sintering the compact. Here, the sintering step is a step of heating the superconducting oxide to a temperature at which the superconducting oxide is decomposed and melted (hereinafter referred to as an anharmonic melting point), and then, in order to grow crystals of the superconducting oxide, A gradual cooling step of gradually cooling the body to below the anharmonic melting point may be included. By heating above the decomposition and melting temperature, the superconducting oxide decomposes into a mixed phase of solid phase and liquid phase. Next, in the cooling step, a peritectic reaction occurs at the interface between the solid phase and the liquid phase, and the superconducting oxide crystal grows. By going through such a sintering step, the orientation of the crystal grains is made uniform, and the superconducting current can flow in the circumferential direction of the superconductor. Further, in order to align the crystal grains of the superconducting oxide which may be contained in the superconductor, the slow cooling step is
The molding may be placed on a substrate made of a single crystal having a lattice constant similar to that of the single crystal of the superconducting oxide. The forming of the superconductor into a tubular shape may be performed at the time of molding or after sintering.

The cylindrical body may have a superconductor and a high resistance substrate, and the superconductor may cover the outer surface or the inner surface of the high resistance substrate. For example, a slurry or paste containing a superconducting oxide may be coated on the high resistance substrate and the above sintering step may be performed. On the other hand, the tubular body may be composed of a superconductor without including a substrate or the like. Examples of the high resistance substrate include oxide ceramics such as magnesium oxide. The current, whether the superconducting fault current limiter is in a steady state or in an abnormal state where overcurrent flows,
It is preferred that the high resistance substrate does not substantially flow. The magnetic shield has a tubular shape as a whole, and the tubular shape can be formed when the tubular bodies are combined. That is, the magnetic shield has a tubular outer wall portion, and the outer wall portion can be formed by combining the tubular bodies. However, even when the superconductors are formed on the outside of each cylinder and there is no gap between the adjacent superconductors, the superconducting current does not have to flow through the adjacent superconductors. On the other hand, the magnetic shield is composed of two or more cylinders,
For example, the cylindrical bodies may be simply arranged in parallel. At this time, a gap is formed between the cylinders.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In FIG. 1, a superconducting fault current limiter 10 is shown.
Has a magnetic shield 11, a cooling container 22 located outside the magnetic shield 11, and a coil 24 wound around the cooling container 22. The magnetic shield 11 is composed of four cylinders 16, and each cylinder 16 forms a hollow portion 15 extending substantially in the axial direction. Each cylindrical body 16 has an outer wall portion 16a and a side wall portion 16b integrally formed,
When the superconducting fault current limiter 10 is in the superconducting state in the steady state, the superconducting conductive current can flow in the circumferential direction of the cylindrical body 16.

The cylindrical body 16 is composed of an arc-shaped outer wall portion 16a forming the outer wall 12, and a side wall portion 16b continuous with the inner side of the outer wall portion 16a. Side wall portion 16b of the adjacent cylindrical body 16
Form side walls 14 with each other. The adjacent side wall portions 16b may or may not be joined. It is preferable that the thickness of the outer wall portion 16a of each cylindrical body 16 be substantially equal to the thickness of the side wall portion 16b. Also, the outer wall portion 16
It is preferable that the thickness of a is constant and the thickness of the side wall portion 16b is also constant. This is because if the thickness is not uniform, local quenching may cause local heat generation, which may cause deterioration of the superconductor. However, the thickness of the wall of this cylinder does not have to be equal to the thickness of the walls of the other cylinders. The magnetic shield 11 has a tubular outer wall 12 and a side wall 14 that is continuous with the outer wall 12 and extends radially inward. The outer and inner surfaces of outer wall 12 are circular. However, the shape of the outer surface and the inner surface of the outer wall is not particularly limited, and may be an ellipse, a polygon, or the like. Further, the direction in which the side wall extends is not limited, and it is not necessary to pass through the center of the magnetic shield.

The outer wall 12 and the side wall 14 are preferably made of a superconducting composition, and more preferably the critical temperature of the superconducting composition is 77K or higher. However, the cylindrical body 16 may have a ceramic base and a superconducting layer covering the surface thereof. At this time, the superconducting layer may be formed on the hollow portion side, that is, on the inner side, or may be formed on the opposite side of the hollow portion, that is, on the outer side. Further, the superconductor may be formed inside and outside the substrate. As the ceramic substrate, magnesium oxide, partially stabilized zirconia, alumina, silicon nitride or the like can be used.

The magnetic shield 12 is located inside the cooling container 22. When using the superconducting fault current limiter, the cooling container 22 can contain a refrigerant such as liquid nitrogen. For example, the coolant is filled until the magnetic shield 12 is immersed, and the gap 23 between the cooling container 22 and the coolant is also filled. However, the smaller the gap 23, the more preferable. This is because the area surrounded by the coil 24 is preferably occupied by the magnetic shield 12 as much as possible from the viewpoint of the current limiting effect.
The cooling container 22 is preferably made of an electrical insulator. For example, a plastic having sufficient mechanical strength such as a fiber reinforced plastic can be used. Further, when the cooling container itself is not an insulator, it is preferable to coat the surface thereof with an electrically insulating layer. The shape of the cooling container is not particularly limited, but it is preferably compatible with the shape of the magnetic shield. For example, when the magnetic shield has a cylindrical shape, it is preferable that the cooling container also has a cylindrical shape.

The coil 24 is the outer peripheral surface 22 of the cooling container 22.
By winding s, the coil 24 is connected to an external circuit (not shown). There is preferably no gap between the coil 24 and the cooling container 22. From the viewpoint of current limiting effect, coil 2
This is because, in the cross section perpendicular to the axial direction of 4, the ratio of the cross sectional area of the superconductor to the cross sectional area of the coil is preferably large. As long as the coil is wound on the outside of the magnetic shield, the coil may be wound on the outside of the cooling container or the inside of the cooling container. When the coil is not superconducting, it is preferably located outside the cooling vessel, as shown in FIG. On the other hand, when the coil is superconducting, it is preferably housed inside the cooling container together with the magnetic shield.

An iron core 26 having a high magnetic permeability is inserted in the hollow portion 15 in order to increase the magnetic flux density penetrating the hollow portion. Although there is a gap between the iron core 26 and the inner surface of the cylindrical body 16, it is preferable that this gap is small. The iron core is made of, for example, silicon steel. Sealing members are preferably attached to both ends of the magnetic shield 11 to prevent the refrigerant from entering the hollow portion 15. The end member may have a plate shape, for example, and may have a recess for receiving the ends of the magnetic shield 11 and the iron core 26. When the magnetic shield becomes normal, eddy currents are generated in the iron core. Then, the eddy current becomes smaller when the temperature of the iron core is closer to room temperature than when it is low temperature such as liquid nitrogen temperature.

The magnetic shield of FIG. 1 can be manufactured by forming each cylinder 16 and combining them. However, the magnetic shield may be formed by forming the hollow body in advance without forming the respective cylinders 16 and sintering the formed body.

The magnetic shield 31 is the magnetic shield 1 of FIG.
Further, eight fan-shaped cylindrical bodies 36 are arranged on the outer circumference of the first unit 1. The four cylinders 35 are arranged so as to form a cylindrical shape, and the outer peripheral surfaces of the respective cylinders 35 are arranged so that the inner peripheral surfaces of the two cylinders 36 are in contact with each other. Each cylinder 3
Reference numerals 5 and 36 form hollow portions extending in the axial direction. An iron core 39 having a shape corresponding to the shape of each hollow portion is inserted into any of these hollow portions. In FIG. 2, the magnetic shield 31 has a cylindrical outer wall 32a, a side wall 33 continuously extending in the radial direction from the inside of the outer wall 32a, and a cylindrical side wall 32b concentric with the outer wall. Side wall 33 and side wall 3
2b is continuous. When the magnetic shield is formed by using the tubular body forming the hollow portion, the shape of each tubular body is not particularly limited, and it is preferable that the tubular body and the adjacent tubular body have the same shape.

In FIG. 3, the magnetic shield is a set of two or more cylinders 42. Each cylindrical body 42 forms a hollow portion 43 extending in the axial direction. The tubular bodies 42 are in contact with each other, and a hollow portion 44 is further formed between the adjacent tubular bodies 42. However, these cylinders do not have to be in contact with each other. The cross-sectional shape of the cylindrical body is not particularly limited, and an ellipse,
It may be polygonal, star-shaped or the like. These tubular bodies 42 are
By putting it inside the cooling container 47, it may be made to stand upright by the force of pushing each other. Alternatively, all of the tubular bodies 42 may be bundled with a wire material such as a coil, and the tubular body 42 and the wire materials may be housed in a cooling container.

The superconducting oxide that can be used in the present invention is not particularly limited, but one having a critical temperature of 77 K or higher is preferable. Examples of such superconducting mixed oxides include Bi-Sr-
Examples thereof include superconducting oxides having a multilayer perovskite type crystal structure such as Ca-Cu-O type and rare earth type. Bi-Sr-Ca-Cu-O
Specific examples of the system oxides include Bi ₂ Sr ₂ CaCu ₂ O _x and Bi ₂ Sr ₂ Ca ₂ Cu.
₃ O _x can be mentioned. Further, part of Sr may be replaced with Pb. Further, as a specific example of the rare earth-based superconducting oxide, a compound represented by REBa ₂ Cu ₃ O _7-x can be mentioned. Here, RE is a rare earth element, Y, Sm, Eu, Dy, Ho,
It consists of at least one element from the group consisting of Er and Yb. In addition, since REBa ₂ Cu ₃ O _7-x is non-stoichiometric, x
Indicates a non-stoichiometric ratio of 0 or more and 1 or less, and this value directly affects the expression of superconducting properties. Moreover, the crystal structure of REBa ₂ Cu ₃ O _7-x has a multilayer perovskite structure. The rare earth element represented by RE is not necessarily limited to only one element, and any two or more elements from the group consisting of Y, Sm, Eu, Dy, Ho, Er and Yb may be mixed,
As such an example, there is a case where RE can be expressed as Y _y Yb _1-y (y is a real number of 0 or more and 1 or less).

If necessary, a small amount of an additive such as silver, platinum, or rhodium for forming pin centers may be added to the superconducting oxide. The pin center prevents the magnetic flux lines from moving when a current flows in the superconducting state, and improves the critical current density. The cylinder and the cylinder used in the present invention are
It can be prepared by molding a mixed powder obtained by adding a desired additive to a superconducting oxide into a desired shape, firing this by a known firing method, and machining.

[0023]

EXAMPLES The present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples. Example 1 A superconducting fault current limiter 10 shown in FIG. 1 was prepared.
However, unlike FIG. 1, the iron core 26 was not inserted.
The magnetic shield 11 is made of Bi ₂ S, which is a bismuth-based superconducting oxide.
It is composed of r ₂ CaCu ₂ O _x . First, a method for manufacturing the magnetic shield 11 will be described. Bi: Sr: Ca: Cu = 2: 2:
Bi ₂ O ₃ , SrCO ₃ , CaC so that the ratio becomes 1: 2.
Powders of O ₃ and CuO were prepared and wet mixed with distilled water using a pot mill. The obtained mixed powder was dried with a hot air dryer and then calcined in air at 860 ° C. for 10 hours. A powder obtained by externally adding 4 wt% of Ag powder to the obtained calcined powder was crushed with a zirconia ball using an ethanol solvent in a ball mill for 10 hours, and then dried in a drier to obtain a raw material powder.

Using this raw material powder, the fan-shaped cylindrical body 16 shown in FIG. 1 was press-molded. The molded body was partially melted in an oxygen atmosphere at 885 ° C. for 30 minutes in a firing furnace to form a mixture of a solid phase and a liquid phase, and then cooled to 830 ° C. at a cooling rate of 0.
It was annealed at 5 ° C./hour and heat-treated for crystallization at 830 ° C. for 15 hours. Then, after further cooling to 700 ° C., the inside of the furnace was replaced with a nitrogen atmosphere and the inside of the furnace was cooled to obtain a fan-shaped superconductor 16 having a hollow portion. By a similar method, a total of four fan-shaped cylindrical bodies 16 were manufactured so that they were combined into a cylindrical shape. The thickness of each cylindrical body 16 was about 5 mm for both the outer wall portion 16a and the side wall portion 16b.
The cross-sectional area of one cylindrical body 16 is 19.6 cm ² . A cylindrical magnetic shield 11 in which these cylindrical bodies 16 are combined
Had a diameter of 100 mm and a length of 100 mm. Also,
The critical temperature of each prepared superconductor is 77K or higher, and the critical current density at 77K, 1 Tesla is about 1K.
It was 000 A / cm ² . As for the magnetic shielding ability, at 77K, when the external magnetic field of the magnetic shield was 50 gauss, the magnetic field at the center of the hollow portion of the magnetic shield 11 was slightly increased.

The magnetic shield 11 is enclosed in a cooling container 22. The container 22 is made of FRP and has a vacuum heat insulating structure, and a disk-shaped lid 28 made of fiber reinforced plastic having a vacuum heat insulating structure is mounted above and below so as to seal the storage space. Liquid nitrogen is filled in the storage container 22 as a coolant 25, and the magnetic shield 11 is immersed in the liquid nitrogen. An inlet and an outlet are formed in this cooling container, and liquid nitrogen is supplied to and discharged from the storage space through these ports. The cooling container 22 has a tubular shape, and a coil 24 is wound around the outer peripheral surface thereof. In this test, the coil is formed by winding one layer of an enamel single wire having a diameter of 1 mm with 200 turns and is connected in series with the power line.

Next, the current limiting action in the embodiment will be described. The magnetic shield 11 arranged in the coil 24 has the same action as a coil having zero resistance in the superconducting state.
That is, a magnetic flux applied by the coil 24 is induced in each cylinder 16 to generate a superconducting current, and the superconducting current shields the magnetic field inside each cylinder 16. Therefore, when the magnetic shield 11 in the superconducting state is located inside the coil 24, the inductance of the coil is extremely suppressed, and as a superconducting fault current limiter, a steady current flows through the coil via the power line. The resistance is extremely low during the period, and the transmission loss due to the fault current limiter is small. However, when an overcurrent flows in the power line and the coil 24 due to a short circuit accident or the like, the coil 24 applies a large magnetic field, so that the cylindrical body 16 is quenched from the superconducting state to the normal conducting state to shield the magnetic field inside the superconductor. Can not be. Therefore, the magnetic flux interlinks with the coil 24, so that a large self-inductance is generated in the magnetic shield 11 and the overcurrent is limited.

With the above-described action, in the superconducting fault current limiter of the present test, the resistance in the steady state was 0.65Ω, while the resistance when the overcurrent was applied was 2.14Ω. This allows
In the event of an accident, the resistance of the superconducting fault current limiter increased by 1.49Ω,
About 3.3 times, it became possible to limit the overcurrent.

Comparative Example A superconducting fault current limiter 50 of FIG. 4 was manufactured. However, unlike FIG. 4, the iron core 59 was not inserted. A cylindrical magnetic shield 51 made of a superconductor was manufactured by the same method as in the example. Magnetic shield 51
Has a diameter of 50 mm and a length of 100 mm, and the wall has a thickness of about 5 mm. The cross-sectional area is 19.6 cm ^2, which is almost the same as that of each cylinder 16 of the embodiment. Moreover, the superconducting characteristics were almost the same as those of the examples. The critical temperature is 77K or higher, and the critical current density at 77K and 1 Tesla is about 1
It was 000 A / cm ² . Also, as the magnetic shield ability, at 77K, the external magnetic field of the magnetic shield is 220
At Gauss, the magnetic field in the center of the hollow portion of the magnetic shield 11 showed about 50 Gauss.

The cooling container 52 has a cylindrical shape corresponding to the shape of the magnetic shield 51, and also has a lid 56.
Similarly, the magnetic shield 51 is enclosed in a cooling container 52, the inside of the cooling container 52 is filled with liquid nitrogen as a coolant 55, and the magnetic shield 51 is immersed in the liquid nitrogen. Similar to the embodiment, a coil 53 is wound around the outer circumference of the cooling container 52 and connected in series with the power line.

As a result of evaluating the resistance of the superconducting fault current limiter 50 as described above in the same manner as the embodiment, the resistance in the steady state is 0.36.
In contrast to Ω, the resistance when applying an overcurrent was 0.73Ω. As a result, at the time of an accident, the resistance of the superconducting fault current limiter increased by only about 2.0 times 0.37Ω, and the overcurrent could not be sufficiently limited. When three superconducting fault current limiters were connected in series in order to suppress overcurrent, the resistance during steady state was 1.08Ω, while the resistance during overcurrent application was 2.1.
It became 9Ω. This made it possible to suppress overcurrent, but the resistance in the steady state exceeded 1 Ω, and transmission loss became a problem.

[0031]

EFFECTS OF THE INVENTION In the superconducting fault current limiter of the present invention, since each small superconductor has a current limiting effect independently, a large-sized superconducting fault current limiter can be more easily produced. In addition, even if one superconductor is damaged due to an accident, the current limiting effect can be obtained to some extent by the other superconductors.

[Brief description of drawings]

FIG. 1 is an embodiment of a superconducting fault current limiter of the present invention.
(A) It is a horizontal sectional view. (B) It is sectional drawing of an axial direction.

FIG. 2 is a horizontal sectional view of an embodiment of the superconducting fault current limiter of the present invention.

FIG. 3 is a horizontal cross-sectional view of one embodiment of the superconducting fault current limiter of the present invention.

FIG. 4 is a conventional superconducting fault current limiter. (A) It is a horizontal sectional view. (B) It is sectional drawing of an axial direction.

FIG. 5 is a vertical sectional view for explaining the operation of the superconducting fault current limiter. (A) A superconducting state in a steady state. (B) The normal conduction state at the time of the accident.

[Explanation of symbols]

10 ... Superconducting fault current limiter, 11 ... Magnetic shield, 12 ... Outer wall, 14 ... Side wall, 15 ... Hollow part, 16 ... Cylindrical body, 16
a ... Outer wall portion, 16b ... Side wall portion, 22 ... Cooling container, 2
2s ... outer peripheral surface, 23 ... gap, 24 ... coil, 25 ...
Refrigerant, 26 ... Iron core, 28 ... Lid, 30 ... Superconducting fault current limiter, 31 ... Magnetic shield, 32a ... Outer wall, 32b ... Side wall, 33 ... Side wall , 35 ... tubular body, 36 ... tubular body, 37 ...
Cooling container, 38 ... Coil, 39 ... Iron core, 40 ... Superconducting fault current limiter, 42 ... Cylindrical body, 43 ... Hollow part, 44 ... Hollow part, 47 ... Cooling container, 48 ... Coil, 49 ... Iron core,
50 ... Superconducting fault current limiter, 51 ... Magnetic shield, 52 ... Cooling container, 53 ... Coil, 55 ... Refrigerant, 56 ... Lid,
59 ... Iron core, 60 ... Superconducting fault current limiter, 62 ... Superconductor, 63 ... Coil, 64 ... Hollow part, 65 ... Magnetic flux line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyuki Matsuda 2-56 Sudacho, Mizuho-ku, Aichi Prefecture Nagoya City

Claims (10)

[Claims] 1. A superconducting fault current limiter having a magnetic shield and a coil wound on the outer side of the magnetic shield, wherein the magnetic shield has a tubular body that forms a hollow portion extending substantially in the axial direction. As described above, the tubular bodies are arranged substantially parallel to each other, and each of the tubular bodies has a superconductor having a tubular shape and capable of flowing a superconducting current in the circumferential direction. A superconducting fault current limiter characterized in that 2. The cylinder according to claim 1, wherein each of the cylinders has a high resistance substrate having a cylindrical shape, and the superconductor coats an outer surface or an inner surface of the high resistance substrate. The superconducting fault current limiter described. 3. The magnetic shield has a tubular outer wall portion, the coil is wound outside the outer wall portion, and the tubular body is combined to form the outer wall portion. The superconducting fault current limiter according to claim 1 or 2. 4. The superconducting fault current limiter according to claim 3, wherein there is substantially no gap between adjacent cylinders. 5. The superconducting fault current limiter according to any one of claims 1 to 4, wherein the thickness of the superconductor is substantially constant. 6. The superconducting fault current limiter according to claim 1, wherein a member having a high magnetic permeability is inserted into each of the hollow portions of the cylindrical body. 7. The superconducting fault current limiter according to claim 6, wherein the member contains silicon and iron. 8. The superconductor according to claim 1, which has a critical temperature of 77 K or higher and contains a superconducting oxide having a multilayer perovskite type crystal structure.
7. The superconducting fault current limiter according to any one of 7. 9. The superconducting fault current limiter according to claim 8, wherein the superconducting oxide contains bismuth, strontium, calcium and copper. 10. The superconducting fault current limiter has a cooling container capable of containing a coolant for cooling the magnetic shield, and the coil is wound outside the cooling container. The superconducting fault current limiter according to any one of claims 1 to 9.