JP2015082543A - Superconductivity current-limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductivity current-limiter capable of preventing reduction of insulation performance in current-limiting operation.SOLUTION: A superconductivity current-limiter 10 includes: plural superconductivity coils 5 with a coil spool 3 each having different diameter which having a superconductivity wire 2 wound along the axial direction of the coil spool 3 on the outer peripheral surface of the cylindrical insulated coil spool 3 plural times without being overlapped with each other, and which are co-axially disposed in an order of diameter size including a predetermined space therebetween to thereby form a current-limiter 1; and an insulating container 9 filled with a refrigerant 8, in which the current-limiter 1 is disposed. The current-limiter 1 is formed so that the diameter of the top of the coil spool 3 becomes smaller than that of the bottom of the coil spool 3 in a vertical direction.

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.

  A conventional superconducting current limiting device has a plurality of superconducting coils formed by winding a thin winding superconducting wire having a rectangular cross-section in a conical spiral shape on a cylindrical winding frame made of an insulator without multiple windings. Contains. A superconducting coil in which the diameter of the winding frame is changed is arranged on the same axis as a current limiting element, and the current limiting element is sealed together with a liquid refrigerant in a cryocontainer which is a heat insulating container. Is done.

  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).

JP 2001-297909 A JP 2002-280213 A JP 2006-237221 A

  However, in the superconducting current limiting device having the above-described structure, 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. Bubbles generated during the current limiting operation may bridge between coil windings (between turns), and there is a problem that high insulation performance cannot be maintained.

  Embodiments of the present invention have been made in view of the above problems, and an object of the present invention is to provide a superconducting current limiting device that can suppress a decrease in insulation performance 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 reel, and concentrically aligning the respective central axes in the order of the outer diameter so as to be spaced apart from each other by a predetermined insulating space, thereby forming the current limiting element. In the superconducting current limiting device disposed in the heat insulating container filled with the refrigerant, the upper diameter D1 of the winding frame in the vertical direction is formed to be smaller than the lower diameter D2.

It is the schematic which shows the whole structure of the superconducting current limiting device which concerns on 1st Embodiment. It is sectional drawing which shows the shape of the winding frame in the superconducting current limiting device which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the current limiting element in the superconducting current limiting device which concerns on 2nd Embodiment. It is the schematic which shows the structure of the superconducting coil in the superconducting current limiting device which concerns on 3rd Embodiment. It is sectional drawing which shows the structure of the superconducting coil in the superconducting current limiting device which concerns on 4th Embodiment. It is sectional drawing which shows the structure of the current limiting element in 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 showing the overall configuration 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 is composed of 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. Each of the superconducting coils 5 is arranged so that the central axes thereof coincide with each other in the vertical direction.

  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.

  Further, as shown in FIG. 2, each cylindrical winding frame 3 is provided with a taper 3a that is angled with respect to the vertical axis so that the upper diameter D1 is smaller than the lower diameter D2. Here, assuming that the upper diameter D1 and the lower diameter D2 are satisfied, D2> D1, and (D2−D1) /D2=0.01 to 0.3. This is because if the above range is less than 0.01, the effect of providing the taper 3a does not appear, and if it exceeds 0.3, the spatially occupied ratio increases and it becomes difficult to realize downsizing.

(Action / Effect)
In the superconducting current limiting device 10 of the present embodiment, the taper 3a having the predetermined shape is provided on the winding frame 3, so that the buoyancy in the vertical direction of bubbles generated during the current limiting operation is increased, and the creeping direction of the superconducting coil 5 is increased. The power of becomes smaller. For this reason, it becomes easy for a bubble to leave | separate upward from the surface, without moving the creeping surface of the superconducting coil 5, and it can suppress the bridge | bridging between windings by a bubble, and can maintain high insulation performance.

[Second Embodiment]
(Constitution)
FIG. 3 is a schematic diagram showing the configuration of the current limiting element in the superconducting current limiting device according to the second embodiment.

  As shown in FIG. 3, in the current limiting element 1 according to the present embodiment, the upper insulating interval W1 is lower than the lower insulating interval W2 with respect to the upper insulating interval W1 and the lower insulating interval W2 formed between the adjacent winding frames 3. It is formed to be larger.

(Action / Effect)
The bubbles generated at the time of current limiting are coupled to each other in the process of moving upward between the superconducting coils 5 and grow larger. In this embodiment, the upper insulating interval W1 above the reel 3 is lower at the lower portion. Since it is formed so as to be larger than the insulation interval W2, the bubbles generated during the current limiting operation can be efficiently discharged and separated from the superconducting current limiting device 10 to the large space above.

  Therefore, according to the superconducting current limiting device of this embodiment, it is possible to suppress a decrease in insulation performance.

[Third Embodiment]
(Constitution)
FIG. 4 is a schematic diagram showing a configuration of a superconducting coil in the superconducting current limiting device according to the third embodiment.

  As shown in FIG. 4, in the superconducting coil 5 according to the present embodiment, the concavo-convex shape 12 is provided on the insulating protrusion 11 positioned between the adjacent superconducting wires 2 wound around the winding frame 3.

(Action / Effect)
In the superconducting current limiting device of the present embodiment, the contact area between the bubbles and the winding frame 3 generated on the surface of the superconducting coil 5 during the current limiting operation is small due to the uneven shape 12 formed on the surface of the insulating protrusion 11 between the superconducting wires 2. Therefore, the separation of bubbles from the surface of the superconducting coil 5 is promoted. For this reason, it is possible to suppress the bridging between the windings due to the bubbles generated during the current limiting operation, and to efficiently discharge to the outside of the superconducting coil 5, and to maintain high insulation performance.

[Fourth Embodiment]
(Constitution)
FIG. 5 is a cross-sectional view showing the configuration of the superconducting coil in the superconducting current limiting device according to the fourth embodiment.

  As shown in FIG. 5, the superconducting coil 5 according to the present embodiment is configured such that a winding groove surface 13 formed at a location where the superconducting wire 2 is wound around the winding frame 3 is parallel to the central axis of the winding frame. . Moreover, the height of the insulation protrusion 11 between the superconducting wires 2 is formed so that the lower part 11b is larger than the upper part 11a.

(Action / Effect)
In the superconducting current limiting device of the present embodiment, since the winding groove surface 13 is parallel to the central axis of the winding frame, it is possible to prevent the unbalanced tension from being applied to the superconducting wire 2 and the insulation distance between the turns. Increases insulation performance. Furthermore, in the superconducting current limiting device of this embodiment, the height of the lower part 11b of the insulating protrusion 11 is made larger than that of the upper part 11a, so that the insulation distance between the superconducting wires 2 can be increased.

  Therefore, according to this embodiment, it is possible to suppress the bridging between the windings due to the bubbles generated during the current limiting operation, and to discharge efficiently to the outside of the superconducting coil 5, and to maintain high insulation performance. it can.

[Fifth Embodiment]
(Constitution)
FIG. 6 is a cross-sectional view showing the configuration of the current limiting element in the superconducting current limiting device according to the fifth embodiment.
As shown in FIG. 6, in the superconducting current limiting device of this embodiment, an ultrasonic vibration device 14 is provided below the winding frame 3 in the current limiting element 1.

(Action / Effect)
In the superconducting current limiting device of the present embodiment, since the superconducting coil 5 is ultrasonically vibrated by the ultrasonic vibration device 14, bubbles generated on the surface of the superconducting coil 5 during the current limiting operation do not grow greatly, and superconductivity is achieved with small bubbles. It becomes easy to separate from the surface of the coil 5.

  For this reason, according to the superconducting current limiting device of the present embodiment, the bubbles generated during the current limiting operation can be efficiently separated from the surface of the superconducting coil 5 without growing greatly, so that the insulation performance can be kept high. it can.

[Other embodiments]
(1) The above embodiments can be combined. For example, in the superconducting current limiting device according to the first embodiment or the second embodiment, the insulating protrusion 11 is provided with the concavo-convex shape 12 as in the third embodiment, or the winding groove as in the fourth embodiment. The surface 13 can be configured to be parallel to the central axis of the reel, or the ultrasonic vibration device 14 can be provided at the lower portion of the reel 3 as in the fifth embodiment.

(2) In the third embodiment, the concavo-convex shape 12 is provided on the entire insulating protrusion 11, but the concavo-convex shape 12 may be provided only on a part of the insulating protrusion 11.

(3) In the fourth embodiment, the winding groove surface 13 is parallel to the center axis of the winding frame, and the height of the insulating protrusion 11 between the superconducting wires 2 is larger in the lower portion 11b than in the upper portion 11a. However, by adopting only one of the configurations, the bubbles can be separated from the surface of the superconducting coil 5 without growing the bubbles greatly, and the insulating performance can be maintained.

(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 5-1 ... Outermost layer coil 5-n ... Innermost layer coil 5-1 / 2 ... Middle layer coil 7 ... Electric field relaxation shield electrode 8 ... Refrigerant 9 ... Cryo container 10 ... Superconducting current limiting device 11 ... Insulation protrusion 11a ... Upper part, 11b ... Lower part 12 ... Uneven shape 13 ... Winding groove surface 14 ... Ultrasonic vibration device

Claims (7)

Prepare a plurality of superconducting coils in which the outer diameter of the winding frame is changed on the outer peripheral surface of the cylindrical insulating winding frame without changing the outer diameter of the winding frame along the axial direction of the winding frame. In the superconducting current limiting device in which the center axes are aligned in the order of the outer diameters and concentrically spaced apart by a predetermined insulating space to form a current limiting element, and the current limiting element is disposed in a heat insulating container filled with a refrigerant. ,
A superconducting current limiting device, wherein the upper diameter D1 of the reel in the vertical direction is formed to be smaller than the lower diameter D2.   The said reel is formed so that the conditions of (D2-D1) /D2=0.01-0.3 regarding the said upper diameter D1 and the said lower diameter D2 may be satisfy | filled. Superconducting current limiting device.   The upper insulating interval W1 formed at the upper part between the adjacent winding frames and the lower insulating interval W2 formed at the lower part between the winding frames are formed such that the upper insulating interval W1 is larger than the lower insulating interval W2. The superconducting current limiting device according to claim 1 or 2, wherein the superconducting current limiting device is provided.   The superconducting current limiting device according to any one of claims 1 to 3, wherein irregularities are formed on a surface of an insulating protrusion provided between superconducting wires of the superconducting coil.   The winding groove surface formed in the location where the said superconducting wire was wound around the said winding frame was arrange | positioned so that it might become parallel to the center axis | shaft of the said winding frame. The superconducting current limiting device described.   6. The superconducting current limiting device according to claim 4, wherein the insulating protrusions between the superconducting wires are formed such that a lower height is larger than an upper height.   The superconducting current limiting device according to any one of claims 1 to 6, wherein an ultrasonic vibration device is provided below the current limiting element.