JP5192741B2 - Superconducting conductor and superconducting cable with superconducting conductor - Google Patents

Description

  The present invention relates to a superconducting conductor formed of a superconducting wire and a superconducting cable including the superconducting conductor. In particular, the present invention relates to a superconducting conductor capable of reducing alternating current loss and a superconducting cable using a superconducting conductor using an oriented substrate superconducting wire that is a superconducting wire using a magnetic substrate as a superconducting wire.

  RE123-based oxide superconductivity (shown as RE-Ba-Cu-O) is called a thin film superconducting wire, and a RE123-based polycrystalline film with uniform crystal grains is provided on a metal tape substrate to a thickness of several μm. Superconducting. However, RE is selected from La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Y. Among RE123-based oxide superconductivity, Y-based superconducting wire (hereinafter referred to as Y-based wire) is known as a representative one. Y-based wires are strong against an external magnetic field and can maintain a high current density even in a strong magnetic field, and therefore are expected to be applied to AC power devices such as superconducting cables. Since there is a limit to the capacity of the current flowing through the thin film superconducting wire, it is necessary to form an aggregate conductor in which a plurality of superconducting wires are bundled in order to increase the current capacity when applied to an AC power device or the like.

  This collective conductor generates a power loss called an AC loss when an AC magnetic field is applied. Therefore, various methods for reducing the AC loss have been proposed.

  Patent Document 1 proposes a method for reducing AC loss by forming two at least two current paths that intersect each other in space by electrically connecting two tape wires facing each other. .

The thin film superconducting wire is obtained by forming a superconducting thin film on a metal substrate. The process of manufacturing a thin film superconducting wire is divided into a process for producing a substrate capable of forming a superconducting thin film (a step for producing a substrate and an intermediate layer) and a process for forming a superconductivity on the substrate (a step for forming a superconducting layer). It is done. There are two main processes for producing a substrate.
One is a technique called IBAD (Ion Beam Assisted Deposition), which is a technique for orienting an intermediate layer by a special film formation method, and the other is a metal substrate (a magnetic substrate mainly using a Ni group). This is a technique called RABiTS (Rolling Assisted Bi-axially Textured Substrate) method. Further, the wire produced by the IBAD method is called an IBAD wire, and the wire produced by the RABiTS method is called an alignment substrate wire (alignment substrate superconducting wire).
JP-A-2005-85612

  The RABiTS method described above has a great advantage that the cost can be kept low because the metal substrate is inexpensive, but a typical alignment metal is based on a Ni group. Since the metal substrate itself is magnetized, when a superconducting cable is manufactured using a wire prepared by the RABiTS method and used under alternating current, a very large alternating current loss occurs. there were.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the AC loss of a superconducting conductor using a superconducting wire having a superconducting layer formed on a magnetic substrate.

  The inventor conducted extensive research on the above-described conventional problems. As a result, in the superconducting cable formed of a superconducting conductor in which a superconducting wire having a superconducting layer and a magnetic substrate is wound around a central member to form a superconducting assembly of two or more layers, the superconducting wire in the outermost layer is centered. It has been found that the AC loss is reduced by winding the superconducting layer so as to face outward with respect to the magnetic substrate in the radial direction of the member. Further, one of the superconducting wires having the magnetic substrate disposed in the inner layer is wound rather than the superconducting wire having the outermost magnetic substrate so that the magnetic substrate faces the magnetic substrate of the outermost superconducting wire. It has been found that the AC loss is further reduced by attaching. Further, the AC loss can be further reduced by using a superconducting wire that uses a non-magnetized substrate such as an IBAD wire instead of a superconducting wire having a magnetic substrate for at least one layer of the superconducting assembly. There was found.

The superconducting conductor according to the first aspect of the present invention includes a cylindrical central member, a substrate, a layer member comprising a superconducting layer and a stabilization layer formed on the substrate, or an intermediate layer and a superconducting layer. the superconducting wire and a layer member comprising a stabilizing layer, a superconducting conductor having at least two or more layers of superconductor assembly formed by winding on the central member, the pre-Symbol superconductor assembly the substrate of the superconducting wire of at least one layer formed is magnetic substrate, and the substrate of the outermost layer of the superconducting wire to form a pre-Symbol superconductor assembly, the outermost layer to form a pre-Symbol superconductor assembly before the substrate of the superconducting wire of at least one layer, it is arranged so as to face the spiral pitch of the superconducting wire of the outermost layer to form the superconductor aggregate, to form the superconductor aggregate excluding To be smaller than the spiral pitch of the superconducting wire having arranged the substrate so as to the face in the substrate of the superconducting wire of the outermost layer, and the previous SL superconducting wire of the outermost layer, before the outermost layer serial superconducting wire wherein before having a arranged the substrate so as to face SL superconducting wire in the substrate of, characterized in that the wound on the central member. Here, the “magnetic substrate” means a metal substrate having a saturation magnetization at an ambient temperature (typically 77 K) or less at which the superconducting conductor is used. In particular, the saturation magnetization during use is 0.15 T. In the case of the above, the effect of this invention is exhibited. Specific examples of the magnetic metal include ferromagnetic materials represented by Fe, Co, Ni, and the like, and alloys based on these.

  Here, the “layer member” is a general term that summarizes the superconducting layer and the stabilizing layer, for example, when the superconducting wire is composed of a substrate, a superconducting layer, and a stabilizing layer. Is a general term that includes the intermediate layer, the superconducting layer, and the stabilizing layer when the substrate, the intermediate layer, the superconducting layer, and the stabilizing layer.

  In addition, “a magnetic substrate is used for the substrate of the superconducting wire forming at least one layer of the superconducting assembly” means that, when the superconducting assembly is a two-layer, it is formed of a superconducting wire using a magnetic substrate. “When the superconducting assembly layer formed by the superconducting wire using the magnetic substrate is only the first layer”, “The superconducting assembly layer formed by the superconducting wire using the magnetic substrate is the first layer. Three cases are included: “when there are only two layers” and “when the layers of the superconducting assembly formed by the superconducting wire using the magnetic substrate are the first layer and the second layer”.

  Further, “the substrate of the superconducting wire forming the superconducting assembly of the outermost layer and the substrate of the superconducting wire forming the superconducting assembly of at least one layer excluding the outermost layer are arranged to face each other. Means that when the superconducting assembly has two layers, “the superconducting wire of the first layer of the superconducting assembly is wound so that the superconducting layer is inward in the radial direction of the central member; In this case, the two-layer superconducting wire is wound so that the superconducting layer faces outward in the radial direction of the central member.

  The superconducting conductor according to the second aspect of the present invention is the superconducting conductor according to the first aspect of the present invention, wherein the layer member of the superconducting wire forming the superconducting assembly is in the radial direction of the central member rather than the substrate. When arranged on the outside, a substrate that is not magnetized is used as the substrate of the superconducting wire.

  The superconducting conductor according to the third aspect of the present invention is characterized in that, in the superconducting conductor according to the second aspect of the present invention, the superconducting wire using the unmagnetized substrate is an IBAD wire.

The superconducting cable according to the first aspect of the present invention has an electrical insulating layer, a protective layer, and a heat insulating tube on the outer periphery of the superconducting conductor according to any one of the first to third aspects of the present invention. Features.

A superconducting cable according to a second aspect of the present invention includes a superconducting conductor according to any one of the first to third aspects of the present invention, an electrical insulating layer formed outside the superconducting conductor, and the electric A superconducting shield having the same structure as the superconducting assembly is provided outside the insulating layer, and a protective layer and a heat insulating layer are provided outside the superconducting shield layer.

  According to the present invention, when a superconducting wire having a magnetic substrate is used as a superconducting wire, and a superconducting conductor formed by the superconducting wire and a superconducting cable including the superconducting conductor are used under alternating current, an AC loss is generated. It is possible to reduce.

  An embodiment of the present invention will be described with reference to the drawings. In addition, the embodiment described below is for explanation, and does not limit the scope of the present invention. Accordingly, those skilled in the art can employ embodiments in which each or all of these elements are replaced by equivalents thereof, and these embodiments are also included in the scope of the present invention.

  FIG. 1 is a diagram showing an example of the structure of a superconducting wire formed on a magnetic substrate used in the present invention. In the superconducting wire 10, an intermediate layer 12 is formed on a magnetic substrate 11, and a superconducting layer 13 is formed on the intermediate layer 12. In addition, a stabilization layer (silver) 14 is formed on the superconducting layer 13, and a conductive tape 15 is soldered on the stabilization layer 14. Here, the layer member in the superconducting wire 10 is a member constituted by the intermediate layer 12, the superconducting layer 13, the stabilization layer 14, and the conductive tape 15.

  FIG. 2 is a diagram showing an example of a superconducting conductor according to the present invention, FIG. 2 (a) is a schematic perspective view of the superconducting conductor, and FIG. 2 (b) is a schematic cross-sectional view.

  As shown in FIG. 2, the superconducting conductor 30 includes a central member 31 and a superconducting assembly 32. The superconducting assembly 32 is a two-layer conductor, and is composed of a first layer 32a and a second layer 32b. Here, the first layer 32a corresponds to the innermost layer, and the second layer 32b corresponds to the outermost layer.

  Also, the superconducting assembly 32 is wound with the superconducting wire 10 on the central member 31, and the first layer 32a is wound so that the superconducting layer 13 is inward in the radial direction of the central member 31, and the second layer 32b. Is formed by winding the superconducting layer 13 so as to face outward in the radial direction of the central member 31. That is, in the first layer 32 a, the superconducting wire 10 is wound so that the outermost layer side of the superconducting conductor 32 becomes the magnetic substrate 11 and the central member 31 side becomes the conductive tape 15. In the second layer 32 b, the superconducting wire 10 is wound so that the outermost layer side of the superconducting assembly 32 becomes the conductive tape 15 and the central member 31 side becomes the magnetic substrate 11.

  In the case of a superconducting assembly 32 of a two-layer conductor (multilayer conductor), by winding the superconducting wire 10 around the second layer 32b (outermost layer) so that the superconducting layer 13 faces outward in the radial direction of the central member 31, AC loss can be reduced. Further, the AC loss can be further reduced by increasing the spiral pitch of the superconducting wire 10 of the second layer 32b (outermost layer). Further, the AC loss can be further reduced by winding the superconducting wire 10 around the first layer 32a (innermost layer) so that the superconducting layer 13 faces inward in the radial direction of the central member 31. Further, the AC loss can be further reduced by increasing the spiral pitch of the superconducting wire 10 of the first layer 32a (innermost layer).

  Next, several preferred embodiments of the present invention will be described.

(Multilayer conductor)
In this embodiment, as shown in FIG. 2, the superconductivity of the two-layer conductor formed by winding the superconducting wire 10 having a width of about 5 mm around the central member 31 made of FRP (fiber reinforced plastic) having a medium outer diameter of 20 mm. A description will be given based on the superconducting conductor 30 including the aggregate 32. The superconducting wire 10 used in this example is a Ni-3 at% W oriented substrate as the magnetic substrate 11, an intermediate layer 12 comprising a CeO2 seed layer, a YSZ barrier layer and a CeO2 cap layer, and a superconducting layer comprising a YBCO film. 13 is a magnetic substrate superconducting wire formed by a stabilizing layer 14 made of Ag. Further, the saturation magnetization of the Ni-3 at% W oriented substrate was 0.42T.

FIG. 3 is a diagram showing a comparison of AC loss due to a difference in the winding method of the superconducting wire 10 of the first layer 32a and the second layer 32b of the superconducting assembly 32. FIG. The horizontal axis in FIG. 3 is a value obtained by dividing the current (maximum value of AC 50 Hz) by the critical current (hereinafter referred to as It / Ic), and the vertical axis indicates the value measured as the AC loss as the square of the critical current. The value divided by.

  The AC loss was compared for four superconducting conductors with different winding methods of the superconducting wire 10 forming the first layer 32a and the second layer 32b of the superconducting assembly 32. The four different superconducting conductors are: (1) the first layer of the superconducting assembly 32 is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31, and the second layer 32b is wound by the superconducting layer 13 as the central member. When wrapping so as to face outward in the radial direction of 31 (outside one layer and outside two layers), (2) the first layer 32 a of the superconducting assembly 32 is directed outward in the radial direction of the central member 31. When the second layer 32b is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31 (inside one layer and two layers), (3) the first of the superconducting assembly 32 When the layer 32a is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31, and the second layer 32b is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31 (1) (Outside 2 layers), (4 The first layer 32a of the superconducting assembly 32 is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31, and the second layer 32b is wound inward in the radial direction of the central member 31. This is the case of winding (within 2 layers in 1 layer). The spiral pitch of the superconducting wire at this time is infinite (straight).

  As shown in FIG. 3, the second layer 32b of the superconducting assembly 32 is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31 (inside one layer, two layers, one layer 2) It was found that all of the loss values of the superconducting conductors in the layer were higher than the theoretical values. In addition, the loss value of the superconducting conductor outside the two layers in one layer becomes a lower loss value than the theoretical value when the horizontal axis It / Ic is 0.42 or more. It was found that the loss value was lower than the theoretical value when It / Ic on the horizontal axis was 0.57 or more. Further, when It / Ic on the horizontal axis is 0.85 or more, the loss value of the superconducting conductor outside the two layers in the first layer is almost the same as the loss value of the superconducting conductor outside the two layers in the one layer. I understood it. From this, it was found that when the superconducting layer 13 of the superconducting wire 10 forming the second layer 32b is wound so as to face outward in the radial direction of the central member 31, the AC loss can be reduced. The theoretical value is a loss value calculated by the Norris elliptic model.

  FIG. 4 is a diagram showing a comparison of AC loss due to a difference in spiral pitch and winding method between the first layer 32a and the second layer 32b of the superconducting assembly 32. In FIG. The horizontal and vertical axes in FIG. 4 are the same as those in FIG.

  When the spiral pitches of the first layer 32a and the second layer 32b of the superconducting assembly 32 are different, the influence of the difference in the winding method of the first layer 32a and the second layer 32b on the AC loss was investigated. The two different superconducting conductors are: (1) the first layer 32a of the superconducting assembly 32 is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31, and the second layer 32b is centered on the superconducting layer 13. When winding so as to face outward in the radial direction of the member 31 (outside one layer and two outside), (2) the first layer 32a of the superconducting assembly 32 is directed inward in the radial direction of the central member 31. And the second layer 32b is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31 (two layers inside one layer). In the two superconducting conductors, the spiral pitch of the first layer 32a of the superconducting assembly 32 is 400 mm, and the spiral pitch of the second layer 32b is -250 mm. Here, the meaning of “-” means that the winding direction of the second layer is opposite to the winding direction of the first layer 32a. The same applies hereinafter.

  As shown in FIG. 4, when It / Ic on the horizontal axis is 0.57 or more, the loss value of the superconducting conductor outside the first layer and the second layer and the loss value of the superconducting conductor outside the first layer and the second layer are: It was found that the loss value was almost the same, and when it was 0.85 or more, it was almost equivalent to the theoretical value. Further, it has been found that by reducing the spiral pitch, the effect of reducing the AC loss becomes smaller than when the spiral pitch shown in FIG. 3 is infinite (straight).

  In FIG. 5, the first layer 32 a is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31, and the second layer 32 b is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31. It is a figure which shows the comparison of the alternating current loss by a difference in the magnitude | size of the spiral pitch of the 1st layer in the case of winding. The horizontal and vertical axes in FIG. 5 are the same as those in FIG.

  The alternating current loss was compared about the winding method of the superconducting wire 10 which forms the 1st layer 32a of the superconducting assembly 32, and two superconducting conductors from which a spiral pitch differs. Two different superconducting conductors are: (1) When the spiral pitch of the first layer 32a is 400 mm and the spiral pitch of the second layer 32b is -250 mm (400 mm in one layer, outside of the second layer -250 mm), (2) First layer This is the case where the spiral pitch of 32a is 800 mm and the spiral pitch of the second layer 32b is -300 mm (800 mm in one layer, -300 mm outside 2 layers).

  As shown in FIG. 5, the loss value of the superconducting conductor of 800 mm in the first layer and the outer layer of 300 mm is less than that of the superconducting conductor of the outer layer of 400 mm in the first layer and the outer layer of 250 mm. It was found that it was reduced. Further, when It / Ic on the horizontal axis is 0.57, the loss value of the superconducting conductor of 800 mm in the first layer and the outer layer of 300 mm in the first layer is about 1/3 of the loss value of the superconducting conductor in the outer layer of 400 mm and the outer layer of 250 mm. When the It / Ic on the horizontal axis is 0.67, it is reduced to about 2/3. Moreover, It / Ic can be suppressed to a level 15% higher than the theoretical value. Thus, by increasing the spiral pitch, it is possible to approach the AC loss when the spiral pitch shown in FIG. 3 is infinite (straight) as compared to FIG. 4 when the spiral pitch is small.

  In FIG. 6, the first layer 32 a of the superconducting assembly 32 is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31, and the second layer 32 b is wound in the radial direction of the superconducting layer 13. It is a figure which shows the comparison of the alternating current loss by a difference in the magnitude | size of the spiral pitch of the 1st layer in the case of winding so that it may become outward. The horizontal and vertical axes in FIG. 6 are the same as those in FIG.

  The alternating current loss was compared about the winding method of the superconducting wire 10 which forms the 1st layer 32a of the superconducting assembly 32, and two superconducting conductors from which a spiral pitch differs. The two different superconducting conductors are: (1) When the spiral pitch of the first layer 32a of the superconducting assembly 32 is 400 mm and the spiral pitch of the second layer 32b is -250 mm (outside one layer 400 mm2 outside layer -250 mm), 2) The case where the spiral pitch of the first layer 32a of the superconducting assembly 32 is 800 mm and the spiral pitch of the second layer 32b is −300 mm (outside one layer 800 mm, outside two layers−300 mm).

  As shown in FIG. 6, the loss value of the superconducting conductor outside the first layer of 800 mm, the outer layer of 2-layer-300 mm, and the loss value of the superconducting conductor of the outer layer of 400 mm2, out of the second layer-250 mm are substantially the same. It was found that there was no difference in AC loss due to the difference in spiral pitch. That is, the spiral pitch shown in FIG. 3 is infinite when the spiral pitch of this level is increased only in the outside of the first layer and the outer layer of FIG. It was found that AC loss in the case of straight) cannot be approached.

When energizing as a superconducting cable actually, it is required that the energizing current It at this time be 0.5 times or more of Ic. Therefore, in the result of AC loss in FIGS. Based on the above results, the following was found.
3 to 6, the winding method of the superconducting wire 10 having the lowest AC loss is the winding method in the first layer and the second layer in FIG. 3 when the spiral pitch is infinite. In the case of winding, the spiral pitch of the first layer 32a in FIG. 5 was 800 mm, and the spiral pitch of the second layer 32b was 300 mm. From this, it was found that the inner layer and the outer layer are optimally wound around the first layer 32a and the second layer 32b. Further, as can be seen from FIG. 5, the reduction in AC loss is greater when the spiral pitch of the first layer 32a and the second layer 32b is increased. However, in FIG. 6 in which the spiral pitch is similarly changed with respect to the outside of the first layer and the second layer where the AC loss is the second lowest in FIG. 3, the AC loss is hardly reduced even when the spiral pitch is increased. .

  From the standpoint of only AC loss, it is optimal that the spiral pitch is infinite and the winding of the first layer 32a and the second layer 32b is outside one layer and outside two layers. From the standpoint of current equalization and mechanical characteristics in the whole, it is preferable to wind the superconducting wire in a spiral shape, and the spiral pitch is made smaller in the outer layer. If it does so, impedance will become high, apparent resistance will go up, the layer which is hard to flow an electric current will be arranged on the outside, and the layer which is easy to flow will be arranged inside, and the whole cable is aimed at leveling. Therefore, when considered as a superconducting cable, the magnetic substrate superconducting wire 10 has a method of winding the first layer 32a and the second layer 32b of the superconducting assembly 32 in one layer and two layers, and has a spiral pitch. By making it as large as possible, AC loss can be effectively reduced. However, it is preferable not to use a straight arrangement.

  Further, the two-layer superconducting assembly 32 is expanded to a multi-layer superconducting assembly 32, and the superconducting wire 10 forming the outermost layer of the superconducting assembly 32 is disposed so that the superconducting layer 13 faces outward in the radial direction of the central member 31. By using a superconducting conductor that is wound in such a manner as to have a larger spiral pitch, AC loss can be effectively reduced. Also, by using a superconducting conductor in which the superconducting wire 10 forming at least one layer excluding the outermost layer of the superconducting assembly 32 is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31. Furthermore, AC loss can be effectively reduced. Further, the use of a superconducting conductor having a larger spiral pitch of the oriented base superconducting wire wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31 further effectively reduces AC loss. I can.

  In addition, when the spiral pitch of the superconducting substrate superconducting wire wound outwardly is less than 500 mm, the influence of the magnetization of the magnetic substrate is increased. Therefore, in place of the superconducting wire 10, the AC loss of the superconducting conductor when an IBAD wire or the like that is a wire whose substrate is not magnetized is used will be verified. The configuration of the IBAD wire used here is a non-magnetic Hastelloy (registered trademark) substrate, an intermediate layer formed by GZO (Gd2Zr2O7) by the IBAD method, and a CeO2 layer formed thereon by the PLD method. The superconducting layer is a YBCO film made of the PLD method, and the stabilizing layer is made of Ag.

  In FIG. 7, the superconducting wire forming the first layer 32a of the superconducting assembly 32 is wound so that the superconducting layer 13 faces inward in the radial direction of the central member 31, and the spiral pitch is 800 mm. When the superconducting wire 13 is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31, and when the spiral pitch is -300 mm, it depends on the wire type of the superconducting wire forming the second layer 32b. It is a figure which shows the comparison of alternating current loss. The horizontal and vertical axes in FIG. 7 are the same as those in FIG.

  The AC loss was compared for two superconducting conductors with different wire types of the superconducting wire forming the second layer 32b of the superconducting assembly 32. Two different superconducting wires are: (1) When the superconducting wire forming the second layer 32b of the superconducting assembly 32 is the superconducting wire 10 (inside one layer, 800 mm, outside two layers-300 mm), (2) the second superconducting assembly 32 This is the case where the superconducting wire forming the two layers 32b is an IBAD wire (800 mm in one layer, IBAD-300 mm in two layers).

  As shown in FIG. 7, the loss value of the superconducting conductor of 800 mm in one layer and IBAD-300 mm in one layer is smaller than the loss value of the superconducting conductor in 800 mm of two layers and from the outer layer of 300 mm. When it was 0.43 or more, it was found that the loss value was lower than the theoretical value.

  In FIG. 8, the superconducting wire forming the first layer 32a of the superconducting assembly 32 is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31, and the spiral pitch is 800 mm. Of the superconducting wire forming the second layer 32b when the superconducting wire 13 is wound so that the superconducting layer 13 faces outward in the radial direction of the central member 31, and the spiral pitch is -300 mm. It is a figure which shows the comparison of the alternating current loss by the difference in wire type. The horizontal and vertical axes in FIG. 8 are the same as those in FIG.

  The AC loss was compared for two superconducting conductors with different wire types of the superconducting wire forming the second layer 32b of the superconducting assembly 32. Two different superconducting conductors are: (1) when the second layer 32b is a superconducting wire 10 (outside one layer 800mm, outside two layers-300mm), (2) when the second layer 32b is an IBAD wire (outside one layer 800mm two layers IBAD -300 mm). In this case, the IBAD is wound so that the superconducting layer faces outward in the radial direction of the central member.

  As shown in FIG. 8, the loss value of the superconducting conductor of 800 mm 2 layers IBAD-300 mm outside the first layer is smaller than the loss value of the superconducting conductor of 800 mm 2 layers outside -300 mm outside the one layer, and the horizontal axis It / Ic is It was found that when the value was 0.57 or more, the loss value was lower than the theoretical value.

  From the above, the second layer (outermost layer) of the superconducting assembly is formed of a superconducting wire with a small spiral pitch when the superconducting wire is wound so that the superconducting layer faces outward in the radial direction of the central member. As a superconducting wire forming the second layer (outermost layer) in the superconducting assembly layer (when it is less than 500 mm), instead of the superconducting wire 10, an IBAD wire that is a non-magnetized wire of the substrate Etc. to form a superconducting assembly, the AC loss of the superconducting conductor can be effectively reduced.

  Moreover, FIG. 9 is a figure which shows an example of the structure of the superconducting cable provided with the superconducting shield by this invention. As shown in FIG. 9, the structure of the superconducting cable 50 includes a superconducting conductor 30 in which a superconducting wire 10 is spirally wound around a metal (for example, copper) central member 31 and an insulating layer 51 ( The material is paper or semi-synthetic paper), then the superconducting shield layer 52, and the cable core on which the protective layer 53 (for example, made of conductive paper or copper braided wire) is formed, is made of flexible metal. It is a structure arranged in a double insulation tube (for example, made of stainless steel or aluminum). The double heat insulating pipe includes an inner pipe 55 and an outer pipe 56 and a heat insulating layer 54 disposed between the inner pipe 55 and the outer pipe 56. Moreover, you may provide an anticorrosion layer further in the outer side of this double heat insulation pipe | tube. Here, the conductor forming the superconducting shield layer 52 is not particularly limited, but it is preferable to use a superconducting wire similar to the superconducting wire 10. As described above, when the superconducting cable includes the superconducting shield layer, the arrangement of the superconducting wires forming the two or more layers of the superconducting shield layer is the same as the arrangement of the superconducting wires of the superconducting assembly. That is, (1) When there are two or more superconducting shield layers, the outermost layer is wound outward, and at least one of the superconducting shield layers located in the inner layer is wound inward. (2) When the spiral pitch is less than 500 mm and the superconducting wire of the second layer (outermost layer) of the superconducting assembly is wound outward in the radial direction of the central member, the second A non-magnetic substrate is used as the superconducting wire substrate of the layer (outermost layer).

It is a figure which shows an example of the structure of the superconducting wire formed into a film on the magnetic substrate used for this invention. It is a figure which shows an example of the superconducting cable by this invention, Fig.2 (a) is a schematic perspective view of a superconducting conductor, FIG.2 (b) is a schematic sectional drawing. It is the figure which showed the comparison of the alternating current loss by the difference in the winding method of the superconducting wire which has the magnetic substrate of the 1st layer and the 2nd layer. It is a figure which shows the comparison of the alternating current loss by the difference in the spiral pitch and winding method of a 1st layer and a 2nd layer. The first layer when the first layer is wound so that the superconducting layer is inward in the radial direction of the central member, and the second layer is wound so that the superconducting layer is outward in the radial direction of the central member It is a figure which shows the comparison of the alternating current loss by a difference in the magnitude | size of spiral pitch. When the first layer is wound so that the superconducting layer faces outward in the radial direction of the central member, the second layer is wound so that the superconducting layer faces outward in the radial direction of the central member. It is a figure which shows the comparison of the alternating current loss by a difference in the magnitude | size of the spiral pitch of a layer. The first layer is wound so that the superconducting layer is inward in the radial direction of the central member, the spiral pitch is 800 mm, and the second layer is so that the superconducting layer is outward in the radial direction of the central member. It is a figure which shows the comparison of the alternating current loss by the difference in the wire type of a 2nd layer, when it winds and also spiral pitch is -300mm. The first layer is wound so that the superconducting layer faces outward in the radial direction of the central member. Further, the spiral pitch is 800 mm, and the second layer is oriented so that the superconducting layer faces inward in the radial direction of the central member. It is a figure which shows the comparison of the alternating current loss by the difference in the wire type of a 2nd layer, when winding and also spiral pitch is -300mm. It is a figure which shows an example of the structure of the superconducting cable provided with the superconducting shield by this invention.

Explanation of symbols

10 Superconducting wire 11 Magnetic substrate 12 Intermediate layer 13 Superconducting layer 14 Stabilization layer (silver)
DESCRIPTION OF SYMBOLS 15 Conductive tape 30 Superconducting conductor 31 Central member 32 Superconducting assembly 50 Superconducting cable 51 Insulating layer 52 Superconducting shield layer 53 Protective layer 54 Heat insulation layer 55 Inner pipe 56 Outer pipe

Claims (5)

A cylindrical central member;
A superconducting wire comprising a substrate and a layer member composed of a superconducting layer and a stabilization layer formed on the substrate or a layer member composed of an intermediate layer and a superconducting layer and a stabilization layer is formed on the central member. A superconducting conductor having at least two or more superconducting aggregates formed by winding,
The substrate of the superconducting wire of at least one layer to form a pre-Symbol superconductor assembly is magnetic substrate,
Said substrate of the outermost layer of the superconducting wire to form a pre-Symbol superconductor assembly, wherein the substrate of the superconducting wire of at least one layer excluding the outermost layer to form a pre-Symbol superconductor assembly is positioned so as to face And
The substrate has the substrate disposed so that a spiral pitch of the superconducting wire of the outermost layer forming the superconducting assembly is opposed to the substrate of the superconducting wire of the outermost layer forming the superconducting assembly. as is smaller than the spiral pitch of the superconducting wire, and before Symbol superconducting wire of the outermost layer, before SL that have a arranged the substrate so as to the face the substrate before Symbol superconducting wire of the outermost layer A superconducting conductor , wherein a superconducting wire is wound on the central member.   When the layer member of the superconducting wire forming the superconducting assembly is disposed outside the substrate in the radial direction of the central member, a substrate that is not magnetized is used as the substrate of the superconducting wire. The superconducting conductor according to claim 1.   The superconducting conductor according to claim 1 or 2, wherein the superconducting wire using the non-magnetized substrate is an IBAD wire.   The superconducting cable which has an electric insulation layer, a protective layer, and a heat insulation pipe | tube in the outer periphery of the said superconducting conductor of any one of Claim 1 to 3. The superconducting conductor according to any one of claims 1 to 3,
An electrically insulating layer formed outside the superconducting conductor;
Furthermore, outside the electrical insulating layer, a superconducting shield having the same structure as the superconducting assembly,
A superconducting cable comprising a protective layer and a heat insulating layer outside the superconducting shield layer.

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