JP2013247731A - Superconducting current limiter - Google Patents

Abstract

The present invention provides a superconducting current limiting device capable of suppressing a decrease in insulation performance even during a current limiting operation.
SOLUTION: A superconducting coil 5 in which a plurality of superconducting wires 2 are wound on the outer peripheral surface of a cylindrical insulating winding frame 3 along the axial direction of the winding frame without overlapping the outer diameter of the winding frame 3 is provided. In a superconducting current limiting device 10 arranged in a heat insulating container 9 filled with a refrigerant 8 by preparing a plurality of them, concentrically separating them by a predetermined insulating space and arranging them as a current limiting element 1 in the order of the outer diameter, A pair of adjacent superconducting coils 5 are wound so that their winding directions are opposite to each other to form a non-inductive winding coil. Further, the outermost superconducting coil 5-1 to the innermost superconducting coil 5-n are connected in series.
[Selection] Figure 1

Description

  Embodiments of the present invention relate to a superconducting current limiting device that suppresses an overcurrent by using a quench phenomenon in which a superconductor phase transitions to a normal conductor due to a critical current.

  The current limiting device is a device that generates impedance by an accident current and suppresses the accident current. In recent years, high-temperature superconductors capable of flowing a large current have come into practical use as wire rods, and application of high-temperature superconductors to current limiting devices has begun to be studied.

  In a resistance type superconducting current limiting device using a high-temperature superconductor, a superconducting coil formed by winding a superconductor around the outer periphery of a winding frame is connected in series to the line, and is kept in a refrigerant in order to keep the temperature below the superconducting transition temperature. Soaked in. When the line current flowing through the superconducting coil of the superconducting current limiting device exceeds the critical current of the superconductor, a function as a current limiting device occurs due to a sudden increase in resistance value due to quenching of the superconductor (normal conducting transition).

  In such a superconducting current limiting device, the superconductor generates heat during the current limiting operation, the refrigerant is vaporized, and the vicinity of the coil is in a gas-liquid mixed state. Since the bubbles deteriorate the insulation performance of the coil, it is essential to have a coil structure in which the insulation performance is not easily lowered even if bubbles are generated in the current limiting device.

JP 2007-274754 A

  However, in the structure of the resistance type superconducting current limiting device as described above, high insulation performance cannot be maintained because bubbles generated during current limiting operation bridge between coil windings (between turns). There was a problem.

  Embodiments of the present invention have been made in view of the above problems, and an object thereof is to provide a superconducting current limiting device that can suppress a decrease in insulation performance even during a current limiting operation.

  In order to achieve the above-described object, an embodiment of the present invention is a superconducting coil in which a plurality of superconducting wires are wound on the outer peripheral surface of a cylindrical insulating winding frame along the axial direction of the winding frame without being overlaid. Are prepared by changing the outer diameter of the winding frame, and these are concentrically arranged in the order of the outer diameter and spaced apart by a predetermined insulating space as a current limiting element, and the current limiting element is filled in a heat insulating container filled with a refrigerant. In the superconducting current limiting device arranged in, the adjacent superconducting coils of the plurality of superconducting coils are wound so that their winding directions are opposite to each other to be non-inductively wound coils, The outermost superconducting coil to the innermost superconducting coil are connected in series.

  Another embodiment of the present invention provides a normal conducting reactor coil in which a plurality of normal conducting wires are wound on the outer peripheral surface of a cylindrical insulating winding frame along the axial direction of the winding frame without being overlaid. Further, the present invention is characterized in that a superconductor having an arbitrary shape is connected in parallel and arranged in a heat insulating container filled with a refrigerant.

  Furthermore, in another embodiment of the present invention, a plurality of thin-film superconducting wires are formed on the outer peripheral surface of a cylindrical insulating reel, and the superconducting wires are crossed on the surface of the superconducting wires, A plurality of normal conductive wires are wound along the outer peripheral surface of the winding frame without being overlaid.

It is the schematic which shows the structural example of the superconducting current limiting device which concerns on 1st Embodiment. It is sectional drawing which shows the example of arrangement | positioning of the superconducting coil in the superconducting current limiting device which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the principal part of the superconducting current limiting device which concerns on 2nd Embodiment. It is the schematic which shows the structural example of the superconducting current limiting device which concerns on 3rd Embodiment. It is the schematic which shows the structural example of the superconducting current limiting device which concerns on 4th Embodiment. It is the schematic which shows the structural example of the superconducting current limiting device which concerns on 5th Embodiment.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

[First Embodiment]
(overall structure)
FIG. 1 is a schematic diagram illustrating a configuration example of the superconducting current limiting device according to the first embodiment. The superconducting current limiting device 10 of this embodiment is configured by housing the current limiting element 1 in a cryocontainer 9 filled with a refrigerant 8.

  The current limiting element 1 includes a plurality of superconducting coils 5..., For example, an outermost layer coil 5-1, an intermediate layer coil 5-n / 2, and an innermost layer coil 5-n. The superconducting coils 5 are concentrically arranged and provided with a predetermined insulating space.

  Arbitrary superconducting coil 5 winds a number of superconducting wires 2 spirally and without overlapping winding on the outer peripheral surface of cylindrical winding frame 3 made of an insulator along the axial direction of the winding frame 3. Is formed. The superconducting wire 2 is formed by laminating thin film superconductors having a rectangular cross section. In addition, electric field relaxation shield electrodes 7 are disposed at both ends of the superconducting wire 2 wound around the winding frame 3 in order to relax the electric field concentrated on the corners of the superconducting wire 2.

(Example of arrangement of superconducting coil 5)
FIG. 2 is a cross-sectional view showing an arrangement example of superconducting coils in the superconducting current limiting device according to the first embodiment. As shown in FIG. 2, the current limiting element 1 is composed of an even number of superconducting coils 5... And two superconducting coils (for example, 5-1 and 5-2) adjacent in order from the end have inductance values. The arrangement is the same, with the winding directions reversed. Moreover, in the non-inductive winding coils 6a, 6b, 6c... Constituted by two adjacent superconducting coils 5, the superconducting coil 5 on the adjacent side of the adjacent non-inductive winding coils 6 has the same winding direction. It is arranged to become. Further, the outermost layer coil 5-1 to the innermost layer coil 5-n are connected in series.

  2 indicate the winding direction of the coil, R indicates right-handed winding, and L indicates left-handed winding.

(Action / Effect)
In the superconducting current limiting device 10 of the first embodiment, two superconducting coils (5-1, 5-2) that are adjacent to each other in order from the end, (5- (n-1), 5-n). The superconducting current limiting device 10 has a very low energy consumption even if the superconducting coil 5 is connected in series with the system because the non-inductive winding arrangement is made by reversing the winding direction of Function as.

  Therefore, according to the superconducting current limiting device 10 of the present embodiment, it is possible to suppress the heat generation of the superconductor during the current limiting operation, thereby suppressing the generation of bubbles due to the vaporization of the refrigerant and the deterioration of the insulation performance.

[Second Embodiment]
(Constitution)
Next, a second embodiment will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment among the structures of the superconducting current limiting device of each following embodiment, and description is abbreviate | omitted.

  FIG. 3 is a cross-sectional view illustrating a configuration of a main part of the superconducting current limiting device according to the second embodiment. As shown in FIG. 3, this superconducting current limiting device 20 is configured by connecting a non-linear element 21 between non-inductive winding coils (6a, 6b) and (6c, 6d). The nonlinear element 21 is formed of a material such as ZnO (zinc oxide).

  The non-linear element 21 is also called a non-linear element, and the relationship between voltage and current follows Ohm's law (linearity) up to a certain threshold voltage. However, when a voltage exceeding the threshold voltage is generated, the resistance rapidly decreases and becomes conductive. It has a characteristic that the current becomes non-linearly increased.

(Action / Effect)
In the superconducting current limiting device 20, when the superconducting coil 5 is quenched by a short-circuit current at the time of an accident and a resistance is generated, a voltage is generated in each superconducting coil 5, and a potential difference is generated between these coil bodies.

  When a voltage equal to or higher than a threshold voltage determined by the characteristics of the nonlinear element 21 disposed between the non-inductive winding coils 6 is generated, the nonlinear element 21 is turned on and the superconducting coil 5 is turned on. When one superconducting coil 5 constituting the non-inductive winding coil 6 is short-circuited, the non-inductive characteristic is lost and the superconducting coil 5 has an inductance component.

  For this reason, the superconducting current limiting device 20 functions to suppress the short-circuit current with both impedances of the resistance component generated by quenching the superconducting coil 5 and the inductance component of the superconducting coil 5. Thereby, the electric current which flows into a superconductor reduces and it can suppress the bubble generation by heat_generation | fever.

  Therefore, according to the superconducting current limiting device 20 of the present embodiment, it is possible to suppress the generation of bubbles due to the vaporization of the refrigerant during the current limiting operation, and to suppress the deterioration of the insulation performance.

[Third Embodiment]
(Constitution)
FIG. 4 is a schematic diagram illustrating a configuration example of the superconducting current limiting device according to the third embodiment. The superconducting current limiting device 30 of the present embodiment includes a normal conducting reactor coil 31 formed in the same manner as in the first embodiment except that a normal conducting wire 32 is used instead of a superconducting wire, and a rod-shaped superconductor 33 in parallel. And stored in a cryocontainer 9, which is a heat insulating container filled with the refrigerant 8.

(Action / Effect)
In this superconducting current limiting device 30, since a current flows through the superconductor 33 during normal operation, the impedance as a device is very small. However, when a short-circuit current flows during an accident, the superconductor 33 is quenched and resistance is generated. A current also flows through the normal conducting reactor coil 31.

  Since an effect of inductance appears when current flows through the normal conducting reactor coil 31, the short-circuit current can be efficiently suppressed by the impedance of both the resistance of the superconductor 33 and the inductance of the normal conducting reactor coil 31. Further, since the short-circuit current is also distributed to the normal conducting reactor coil 31, the current flowing through the superconductor 33 is reduced, and the generation of bubbles due to heat generation from the superconductor 33 can be reduced.

  Therefore, according to the superconducting current limiting device 30 of the present embodiment, it is possible to suppress the generation of bubbles due to the vaporization of the refrigerant during the current limiting operation, and to suppress the deterioration of the insulation performance.

[Fourth Embodiment]
(Constitution)
FIG. 5 is a schematic diagram illustrating a configuration example of the superconducting current limiting device according to the fourth embodiment. The superconducting current limiting device 40 of the present embodiment is a heat insulating container filled with the refrigerant 8 by connecting the normally conducting reactor coil 31 of the third embodiment and the current limiting element 1 of the first embodiment in parallel. It is stored in a certain cryo container 9.

(Action / Effect)
In this superconducting current limiting device 40, since a current flows through the current limiting element 1 during normal operation, the impedance as a device is very small. However, if a short-circuit current flows during an accident, the superconducting coil 5 in the current limiting element 1 is configured. The superconducting wire 2 is quenched to generate resistance and has an inductance component.

  On the other hand, current also flows through the normal conducting reactor coil 31, and the effect of the inductance of the normal conducting reactor coil 31 appears. For this reason, a short circuit current can be efficiently suppressed with the impedance by the resistance component and inductance component of the superconducting coil 5, and the inductance component of the normal conducting reactor coil 31. Further, since the short-circuit current is also diverted to the normal conducting reactor coil 31, the current flowing through the current limiting element 1 is reduced, and the generation of bubbles due to heat generation from the superconducting coil 5 can be reduced.

  Therefore, according to the superconducting current limiting device 40 of the present embodiment, it is possible to suppress the generation of bubbles due to the vaporization of the refrigerant during the current limiting operation, and to suppress the deterioration of the insulation performance.

[Fifth Embodiment]
(Constitution)
FIG. 6 is a diagram illustrating an example of the configuration of the superconducting current limiting device according to the fifth embodiment. The superconducting current limiting device 50 of the present embodiment is provided with a superconducting wire 42 in advance in a direction orthogonal to the winding direction of the normal conducting wire 32 of the normal conducting reactor coil 31 of the third embodiment shown in FIG. A superconductor and a normal conducting coil are integrated. That is, the superconducting current limiting device 50 is provided with a plurality of superconducting wires 42 in a straight line on the outer peripheral surface of the winding frame 3, and is brought into close contact with the outer surface of the superconducting wire 42 so as to fix the superconducting wires 42. Is formed by integrating a superconductor and a normal conducting coil.

(Action / Effect)
The superconducting current limiting device 50 of the fifth embodiment has a coil configuration in which a superconductor and a normal conducting coil are integrated in parallel, and a current flows through the superconducting wire 42 during normal operation. It is getting smaller.

  When a short-circuit current flows at the time of an accident, the superconducting wire 42 is quenched and resistance is generated, and a current also flows through the portion of the normal conducting reactor coil 31. Since an inductance effect appears when a current flows through the normal conducting reactor coil 31, the short-circuit current can be efficiently suppressed by the impedance of both the resistance of the superconducting wire 42 and the inductance of the normal conducting reactor coil 31. Further, since the short-circuit current is also diverted to the normal conducting reactor coil 31, the current flowing through the superconducting wire 42 is reduced, and the generation of bubbles due to heat generation can be reduced.

  Therefore, according to the superconducting current limiting device 50 of the present embodiment, it is possible to suppress the generation of bubbles due to the vaporization of the refrigerant during the current limiting operation differential and to suppress the deterioration of the insulation performance. In the superconducting current limiting device 50, the superconducting wire 42 is fixed by the normal conducting wire 32. Therefore, even if a large electromagnetic force is generated when a short-circuit current flows through the superconducting wire 42, the superconducting wire 42 is wound on the reel 3 Can be prevented from coming off.

[Other embodiments]
(1) In the second embodiment (FIG. 3), the non-linear element 21 is connected between the non-inductive winding coils (6a, 6b) and between (6c, 6d). The non-linear element 21 may be connected between the non-inductive winding coils, or the non-linear element 21 may be connected to only a part thereof.

(2) In the third embodiment (FIG. 4), the superconductor 33 having a rod shape is used, but the shape of the superconductor 33 is not limited, and may be formed in a plate shape or a coil shape.

(3) In the fourth embodiment (FIG. 5), the current limiting element 1 and the normal conducting reactor coil 31 are arranged on the outside and connected in parallel. However, the outer diameter of the current limiting element 1 is the normal conducting reactor. The current limiting element 1 may be arranged concentrically inside the normal conducting reactor coil 31 by making it smaller than the outer diameter of the coil 31. On the contrary, the normal conducting reactor coil 31 can be concentrically arranged inside the current limiting element 1 by making the outer diameter of the normal conducting reactor coil 31 smaller than the outer diameter of the current limiting element 1.

(4) Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Current limiting element 2 ... Superconducting wire 3 ... Winding frame 5 ... Superconducting coil 5-1 ... Outermost layer coil body 5-n / 2 ... Middle layer coil body 5-n ... Innermost layer coil body 6, 6a, 6b, 6c ... Non-inductive coil 7 ... Electrical relaxation shield electrode 8 ... Refrigerant 9 ... Cryo container 10, 20, 30, 40, 50 ... Superconducting current limiting device 21 ... Nonlinear element 31 ... Normal conducting reactor coil 32 ... Normal conducting wire 33 ... Superconducting Body 42 ... Superconducting wire

Claims (5)

A plurality of superconducting coils are prepared by changing the outer diameter of the winding frame on the outer peripheral surface of the cylindrical insulating winding frame along the axial direction of the winding frame without overlapping the superconducting wires, In the superconducting current limiting device arranged concentrically in the order of the outer diameter and spaced apart by a predetermined insulating space as a current limiting element, the current limiting element is disposed in a heat insulating container filled with a refrigerant,
Among the plurality of superconducting coils, a pair of adjacent superconducting coils are wound so that their winding directions are opposite to each other to form a non-inductive winding coil, and further, from the outermost superconducting coil to the innermost layer. A superconducting current limiting device comprising a superconducting coil connected in series.   The superconducting current limiting device according to claim 1, wherein a non-linear element is connected between the non-inductive coil and the non-inductive coil adjacent to the non-inductive coil.   A normal conducting reactor coil in which a plurality of normal conducting wires are wound on the outer peripheral surface of a cylindrical insulating winding frame along the axial direction of the winding frame without overlapping, and the current limiting element are connected in parallel. The superconducting current limiting device according to claim 1, wherein the superconducting current limiting device is disposed in a heat insulating container filled with a refrigerant.   A normal conducting reactor coil in which a plurality of normal conducting wires are wound on the outer peripheral surface of a cylindrical insulating winding frame along the axial direction of the winding frame without overlapping, and a superconductor having an arbitrary shape are arranged in parallel. And a superconducting current limiting device, characterized in that they are arranged in a heat insulating container filled with a refrigerant.   A plurality of thin film superconducting wires are formed on the outer peripheral surface of the cylindrical insulating winding frame, and the normal conducting wire is formed along the outer peripheral surface of the winding frame while intersecting the superconducting wire on the surface of the superconducting wire. A superconducting current limiting device characterized in that a plurality of windings are wound without overlapping.

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