WO2017003127A1 - Superconducting wire - Google Patents

Abstract

The present invention relates to a superconducting wire having improved electrical and physical properties.

Description

Superconducting Wire Rod

The present invention relates to a superconducting wire. More specifically, the present invention relates to a superconducting wire with improved electrical and physical properties.

Superconducting wires have near-zero electrical resistance at a constant temperature, so they have great power transfer capability even at low voltages.

The superconducting cable having such a superconducting wire uses a method of cooling using a refrigerant such as nitrogen and / or a method of thermal insulation to form a vacuum layer in order to form and maintain a cryogenic environment.

The superconducting wires constituting the conventionally introduced superconducting cable may be wound in a drum or the like while being spirally wound on the outside of the former to manufacture the superconducting cable, or continuous tension or torsion may be applied when the superconducting cable is bent in the installation section. In addition, such stress may cause problems such as breaking of the superconducting wire having a thickness of about 0.1 mm. In particular, since the ratio of the cost of the superconducting wire in the total superconducting cable is the largest, the durability or physical reliability of the superconducting wire is required.

In addition, the superconducting wire should not be broken or deformed in the situation where physical stress such as tensile force or torsion is applied, and furthermore, stable electrical characteristics should be ensured.

An object of the present invention is to provide a superconducting wire having improved electrical and physical properties.

In order to solve the above problems, the present invention has a width of 0.4 millimeters (mm) to 0.5 millimeters (mm) and a thickness of 0.3 millimeters (mm) to 0.5 millimeters (mm), YBCO or ReBCO (Re = Sm, In the superconducting wire used with Gd, Nd, Dy, Ho), the threshold current (DC Ic) at a temperature of 77 K, 1 atm, and self-field may be 150 A to 500 A.

Here, the threshold current may be 95% or more of the threshold current when the bending stress is applied after the superconducting wire is sequentially changed by using two rollers having a diameter of 35 millimeters (mm).

In addition, the threshold current may be 95% or more of the threshold current when the double-banding stress is applied after the superconducting wire is sequentially changed by using four rollers having a diameter of 50 millimeters (mm).

In addition, when the superconducting wire is subjected to a 250 MPa longitudinal tensile force or a longitudinal tensile force that is 0.2% elongated, the tensile threshold current may be 95 percent or more of the threshold current.

In addition, the torsional threshold current when the superconducting wire is twisted at intervals of 200 millimeters (mm) in the longitudinal direction may be 95 percent or more of the threshold current.

And, if the winding of the superconducting wire to the pitch of about 220 millimeters (mm) to the former of the superconducting cable and a load of 3 kg ~ 8 kg in the longitudinal direction of the superconducting wire is applied, the threshold current is not less than 95 percent of the threshold current Can be.

In addition, the superconducting wire is bonded in a unit of 200 meters (m) to 400 meters (m), the resistance of the junction portion may be 200 n 200 or less.

In this case, the joint resistance is 240 by the pitch of about 220 millimeters (mm) of the superconducting wire to the former of the superconducting cable, and the bonding resistance for each joining portion 240 is applied to the load of 3 kg ~ 8 kg in the longitudinal direction of the superconducting wire n or less, or may be increased to 20 percent or less than the steady state junction resistance.

In this case, the threshold current when the superconducting wire is immersed in 30 atmospheres of liquid nitrogen for 16 hours may be 95 percent or more of the threshold current.

In addition, the slope of the voltage with respect to the current above the threshold current may be 25 to 30.

In addition, the AC loss of the superconducting wire may be 0.4 W / kA * m or less.

In order to solve the above problems, the present invention has a width of 0.4 millimeters (mm) to 0.5 millimeters (mm) and a thickness of 0.3 millimeters (mm) to 0.5 millimeters (mm), YBCO or ReBCO (Re = Sm, In the superconducting wire used with Gd, Nd, Dy, Ho), the critical current (DC Ic) at a temperature of 77 K, 1 atm, and the self-field is 150 A to 500 A or less, and the superconducting wire is 35 mm in diameter. When bending stress is applied after bending and bending in two sequential directions, double-bending after bending the superconducting wire sequentially using four rollers having a diameter of 50 mm (mm) When stress is applied, when 250 MPa longitudinal tensile force or 0.2% elongated longitudinal force is applied to the superconducting wire, the superconducting wire is twisted at intervals of 200 millimeters (mm) in the longitudinal direction, or superconducting When the superconducting wire is wound around 220 millimeters (mm) in the former of the cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire, or the superconducting wire is a liquid whose internal pressure is maintained at about 30 atmospheres. The critical current in the state of immersion in nitrogen for 16 hours satisfies 95% or more of the critical current, the superconducting wire is bonded in the unit of 200 meters (m) to 400 meters (m), the resistance of the junction is 200nΩ or less The joining resistance is 240 n 별 for each joining part in which the superconducting wire is wound around 220 millimeters (mm) in pitcher of the superconducting cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire. Or less than 20 percent more than the steady state junction resistance, the slope of the voltage for the current above the critical current is 25 to 30, and the AC loss is 0.4 W / kA * m It is possible to provide a superconducting wire, it characterized in that a servant.

In addition, in order to solve the above problems, the present invention has a width of 0.4 millimeters (mm) to 0.5 millimeters (mm) and a thickness of 0.3 millimeters (mm) to 0.5 millimeters (mm), YBCO or ReBCO (Re = In superconducting wires using Sm, Gd, Nd, Dy, and Ho), swelling of the superconducting wires was not visually observed when the superconducting wires were immersed in liquid nitrogen at an internal pressure of about 30 atm for 16 hours. It is possible to provide a superconducting wire, characterized in that not.

In addition, in order to solve the above problems, the width is 0.4 millimeters (mm) to 0.5 millimeters (mm) and the thickness is 0.3 millimeters (mm) to 0.5 millimeters (mm), YBCO or ReBCO (Re = Sm, Gd as a superconducting material) , Nd, Dy, Ho) is used, the critical current (DC Ic) at a temperature of 77K, 1 atm, self-field is 150A to 500A or less, the superconducting wire is 35mm in diameter (mm) When the bending stress is applied after bending and bending sequentially using two rollers, the double-bending stress after bending by bending the superconducting wire sequentially using four rollers having a diameter of 50 millimeters (mm). When is applied, when the 250 MPa longitudinal tension or 0.2% elongated longitudinal force is applied to the superconducting wire, the superconducting wire twisted at intervals of 200 millimeters (mm) in the longitudinal direction, or superconducting cable When the superconducting wire is wound around 220 millimeters (mm) in a pitcher and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire, or the superconducting wire is maintained in an internal pressure of about 30 atm. The critical current in the state of immersion in nitrogen for 16 hours satisfies 95% or more of the critical current, the superconducting wire is bonded in the unit of 200 meters (m) to 400 meters (m), the resistance of the junction is 200nΩ or less The joining resistance is 240 n 별 for each joining part in which the superconducting wire is wound around 220 millimeters (mm) in pitcher of the superconducting cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire. Or less than 20 percent more than the steady state junction resistance, the slope of the voltage for the current above the critical current is 25 to 30, and the AC loss is 0.4 W / kA * m or less It said, the peeling off of the superconducting wire in a state of immersion for 16 hours in liquid nitrogen that is maintained at a pressure of 30 atmospheres inside the superconducting wire can provide a superconducting wire, characterized in that which is not observed with the naked eye.

The superconducting wire according to the present invention may be reinforced with physical stiffness to withstand physical stresses such as tension or torsion that may be applied to the superconducting wire in the manufacturing and laying of the superconducting cable.

In addition, the superconducting wire according to the present invention may be reinforced with physical stiffness to prevent breakage of the superconducting wire, and at the same time, to ensure physical stiffness against physical stress and at the same time, to ensure electrical properties.

In addition, according to the superconducting wire according to the present invention, the physical rigidity of the superconducting wire is improved in the manufacturing process, installation process and operation of the superconducting cable, and also ensure the electrical characteristics, greatly reducing the manufacturing cost due to disconnection of the superconducting wire. Can be.

Figure 1 shows a stepped stripped perspective view of the superconducting wire according to the present invention.

2 shows a cross-sectional view of the superconducting cable shown in FIG. 1.

3 shows an example of a superconducting wire rod that can be applied to a superconducting cable.

4 shows a cross-sectional view of several examples of superconducting wires that may be applied to the superconducting wires according to the present invention.

Figure 5 shows a test facility for the bending test of the superconducting wire according to the present invention.

6 shows a voltage graph according to the current flowing in the superconducting wire.

7 shows a hermeticity test facility of the superconducting wire according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. Like numbers refer to like elements throughout.

1 shows a stepped-away perspective view of a superconducting cable to which a superconducting wire is applied according to the present invention, and FIG. 2 shows a cross-sectional view of the superconducting cable shown in FIG. 1.

The basic structure of the superconducting cable to which the superconducting wire according to the present invention is applied will be described.

The superconducting cable shown in FIG. 1 includes at least one superconducting conductor layer 130 including a former 110 and a plurality of superconducting wires arranged side by side in the longitudinal direction of the former 110 so as to surround the outside of the former 110. ), At least one including a plurality of superconducting wires arranged side by side in the longitudinal direction of the former 110 so as to surround the superconducting conductor layer 130, the insulating tape 140 to the outside. Core portion 100 including the superconducting shielding layer 180 or more layers, in order to cool the core portion 100, is provided outside the core portion 100, the liquid phase for cooling the core portion 100 Cooling unit 200 having a refrigerant flow path of the refrigerant, the inner metal tube 300 provided on the outside of the cooling unit 200, the inner metal tube 300 is provided outside, the heat insulating material 401 is wound in several layers Thermal insulation 400 to form a thermal insulation layer, phase In order to vacuum-insulate the cooling unit 200, the vacuum unit 500 having a plurality of spacers 560 at spaced apart positions outside the heat insulating unit 400, and an external metal tube provided outside the vacuum unit 500. 600 and an outer jacket 700 provided outside the outer metal tube 600 to form a sheath layer.

The components of the superconducting cable are sequentially reviewed as follows. The former 110 serves as a frame for forming a shape while simultaneously providing a place for mounting the flat, flat, long superconducting wire around the former 110, and may be a path through which an accident current flows. The former 110 may have a shape in which a plurality of copper (Cu) conductor wires 111 having a circular cross section are compressed in a circular shape.

Specifically, the former 110 basically has a round cylindrical shape, and serves as a frame for raising a flat long superconducting wire. The diameter of the former 110 is determined so that the superconducting wires are not lifted in consideration of the width of the superconducting wires, and thus the superconducting wires are placed on the former 110 as close as possible.

As shown in Figures 1 and 2, the former may be configured in the form of a full center, the former 110 is made of a hollow pipe shape and at the same time a refrigerant to act as a frame for raising the superconducting wire rod It may be configured to serve as a path for movement, each of the conductor wires 111 constituting the former may be composed of copper, etc., by connecting each wire in parallel with each superconducting wire, power in the power system It can also be configured to act as a return conductor in the event of fault currents resulting from short circuits in the system (quench, lightning, breakdown, etc.).

The role of the return conductor when a fault current is generated in the power system is attached to each superconducting wire as described below, in addition to the former composed of the conductor element 111, and a conductive layer of a metallic material is present at room temperature. The energizing layer may be in the form of a tape of a metal material. Detailed description thereof will be described later.

Depending on the capacity of the fault current, the conductor cross-sectional area of copper or the like constituting the wire may be determined. In the case of high pressure, the copper wire may be compressed into a circular shape to form a stranded wire.

As will be described later, the superconducting wire according to the present invention is provided with a conductive layer made of a metal material at room temperature on both surfaces of the superconducting wire to reinforce mechanical rigidity. Such a conductive layer may reinforce mechanical stiffness to prevent breakage due to torsional stress during winding of the superconducting wire.

Such conduction layer reinforces the mechanical stiffness of the superconducting wire and at the same time can perform the role of the fault current with the former in the event of an accident such as a short circuit, the superconductor of the superconducting cable applied superconducting wire according to the present invention is conventional It may have a diameter smaller than the diameter of the former constituting the general superconducting cable. A detailed explanation will be given later.

Since the conductor strands 111 having a plurality of cross-section circular conductors constituting the former 110 form a stranded wire compressed into a circular shape, the surface of the former 110 is inevitably convex. Accordingly, the smoothing layer 120 may be coated on the outside of the former 110 to smooth the convex surface of the former 110. The smooth layer 120 may be made of a material such as semi-conductive carbon paper or brass tape.

Although not shown in the drawing, the cushion layer may be further provided between the smoothing layer 120 and the superconducting conductor layer 130. The cushion layer may be provided to protect the superconducting conductor layer by using a semiconductive carbon paper tape.

A first superconducting conductor layer 130a may be provided outside the former 110 flattened by the smoothing layer 120 to form a layer surrounded by a plurality of superconducting wires 131. The first superconducting conductor layer 130a may be installed such that a plurality of superconducting wires are adjacent to each other and surround the smooth layer 120.

In addition, as illustrated in FIG. 1, the superconducting conductor layer 130 may be configured in multiple layers according to the capacity of a current to be transmitted or distributed through the superconducting cable.

1 shows that a total of two superconducting conductor layers 130a and 130b are provided.

When the superconducting conductor layer is provided as a multilayer, an insulating tape 140 may be provided between the superconducting conductor layers 130a and 130b. The reason why the insulating tape 140 is disposed between the superconducting layers 130a and 130b is to control the direction of the current of the superconducting layers 130a and 130b constituting each layer. If the insulating tape 140 is not provided, the path of the current may be disturbed so that the current may not flow in the intended direction. The direction of energization of the superconducting conductor layers stacked in multiple layers by the insulating tape 140 may match.

Incidentally, if the insulating tape 140 is provided, the skin effect of the superconducting wires constituting each superconducting conductor layer can be prevented.

In the embodiment shown in Figure 1, the superconducting conductor layer 130 is shown an example consisting of two layers of the first superconducting conductor layer 130a and the second superconducting conductor layer 130b, but if necessary superconducting of more layers A conductor layer may be provided.

In addition, each of the superconducting wires constituting the superconducting conductor layers 130a and 130b may be connected in parallel with the element wires constituting the former 110. This is to allow the accident current to be classified into a wire of the former 110 when an electric current flowing through the superconducting wire is shorted (wrench, lightning, insulation breakdown, destruction of superconducting conditions, etc.). In this way, it is possible to prevent heat generation or damage to the superconducting wire.

An internal semiconducting layer 150 may be provided outside of the second superconducting conductor layer 130b provided outside the first superconducting conductor layer 130a. The inner semiconducting layer 150 may be provided to relieve electric field concentration for each region of the superconducting conductor layer 130 and to even the surface electric field. Specifically, it may be provided to alleviate the electric field concentration occurring in the corner portion of the superconducting wire, and to even the electric field distribution. This also applies to the outer semiconducting layer 170 described later.

The inner semiconducting layer 150 may be provided in a manner in which a semiconducting tape is wound.

An insulating layer 160 may be provided outside the inner semiconducting layer 150. The insulating layer 160 may be provided to increase the insulation strength of the superconducting cable. Generally, XLPE (Cross Linking-Polyethylene) or oil filled cable (oil filled cable) is used to insulate the high voltage cable, but the superconducting cable is cooled to cryogenic temperature for superconductivity of superconducting wire, and at the cryogenic temperature, XLPE breaks and breaks down. Since there is a problem, and an oil filled cable may cause environmental problems, the superconducting cable to which the superconducting wire according to the present invention is applied may use an insulating paper made of a general paper as the insulating layer 160, and the insulation The layer 160 may be configured by winding insulating paper a plurality of times.

The insulation paper is mainly used kraft paper or PPLP (Polypropylene Laminated Paper). In the case of superconducting cables, PPLP insulating paper is used in consideration of the ease of winding and dielectric strength characteristics.

An outer semiconducting layer 170 may be provided outside the insulating layer 160. The outer semiconducting layer may also be provided to relieve electric field concentration by each region of the superconducting conductor layer 130 and to even the surface electric field. The outer semiconducting layer 170 may also be provided in a manner in which a semiconducting tape is wound. .

In addition, a superconducting shielding layer 180 may be provided outside the outer semiconducting layer 170. The method of forming the superconducting shield layer 180 may be the same as the method of forming the superconducting conductor layer 130. When the surface of the outer semiconducting layer 170 is uneven, a smooth layer (not shown) may be provided as necessary, and superconducting wires for forming a superconducting shielding layer 180 outside the smooth layer are circumferentially respectively. Can be placed side by side.

The current flowing through the shielding layer made of the second generation superconducting wire may be designed to be about 95% of the current flowing in the superconducting conductor layer, thereby minimizing the leakage magnetic field.

A core exterior layer 190 may serve as an exterior of the core unit 100 outside the superconducting shielding layer 180. The core exterior layer 190 may include various tapes, binders, and the like, and serves to bind all components of the core unit 100 and the exterior role so that the core unit 100 may be exposed to the cooling layer to be described later. To perform, it may be composed of a metal tape such as SUS material.

In this manner, the core portion 100 of the superconducting cable may be configured. In FIGS. 1 and 2, the smoothing layer and the semiconducting layer are illustrated as being composed of a single layer of the same material. Can be added.

The cooling unit 200 may be provided outside the core unit 100. The cooling unit 200 may be provided to cool the superconducting wire of the core unit 100, and the cooling unit 200 may be provided with a circulation passage of the liquid refrigerant therein. Liquid nitrogen may be used as the liquid refrigerant, and the liquid refrigerant (liquid nitrogen) is provided in the core part 100 inside the cooling unit while circulating the cooler flow path in a cooled state to have a temperature of about −200 degrees. Cryogenic temperature, which is a superconducting condition of the superconducting wire, can be maintained.

The cooling passage provided in the cooling unit 200 may allow the liquid refrigerant to flow in one direction, may be recovered from the junction box of the superconducting cable, recooled, and then supplied to the cooling passage of the cooling unit 200 again.

An inner metal tube 300 may be provided outside the cooling unit 200. The inner metal tube 300 serves as an exterior of the superconducting cable to prevent mechanical damage of the core unit 100 during installation and operation of the superconducting cable together with the outer metal tube 600 to be described later. The superconducting cable is wound on the drum to facilitate the manufacture and transportation, and when installed, the cable wound around the drum is deployed to install the superconducting cable so that bending stress or tensile stress can be continuously applied.

In order to maintain initial performance even in the situation where such mechanical stress is applied, the inner metal tube 300 may be provided. Therefore, the inner metal tube 300 has a corrugated structure in which bumps and depressions are repeated in the longitudinal direction of the superconducting cable in order to reinforce rigidity against mechanical stress, and the inner metal tube 300 is made of a material such as aluminum. Can be.

Since the inner metal tube 300 is provided outside the cooling unit 200, the inner metal tube 300 may be cryogenically corresponding to the temperature of the liquid refrigerant. Therefore, the inner metal pipe 300 may be divided into a low temperature metal pipe.

In addition, the outer circumferential surface of the inner metal tube 300 may be provided with a heat insulating part 400 including a heat insulating layer wound in a plurality of layers of a heat insulating material coated with a thin polymer of low thermal conductivity on a metal film with high reflectance. The heat insulation layer may be configured to constitute a multi layer insulation (MLI) and to prevent heat intrusion to the inner metal pipe 300.

In particular, since the inner metal tube 300 is made of a metal material, heat intrusion or heat exchange due to conduction is easy, and the heat insulating part 400 can minimize heat exchange or heat intrusion mainly due to conduction, and has a high reflectance metal. Due to the film material, it is also possible to obtain an effect of preventing heat exchange or thermal intrusion by radiation.

The number of layers of the heat insulating part 400 is adjustable to minimize thermal intrusion. If it is composed of many layers, the radiant heat shielding effect is increased, but it is important to use an appropriate number of layers since the heat shielding effect of the conduction heat and the thermal barrier effect due to convection due to the thinning of the vacuum layer are reduced.

The vacuum unit 500 may be provided outside the heat insulating part 400. The vacuum unit 500 may be provided to minimize heat transfer due to convection in the direction of the heat insulation layer, which may occur when heat insulation by the heat insulation unit 400 is not sufficient.

The vacuum unit 500 may be formed by forming a spaced space outside the heat insulating portion 400 and vacuuming the spaced space.

The vacuum part 500 is a separation space provided to prevent thermal intrusion by convection or the like from the outside at room temperature to the core part side, and may include at least one spacer 560 to form a physical separation space. In order to prevent contact between the outer metal tube 600 and the heat insulating part 400 inside the vacuum part 500 provided at an outer side of the space in the vacuum part 500 in the entire area of the superconducting cable. At least one spacer 560 may be provided therein, and may be increased or decreased according to the type or size of the superconducting cable or the spacer. Although the superconducting cable 1000 illustrated in FIGS. 1 and 2 is illustrated as having four spacers, the number thereof may be increased or decreased.

The spacer 560 may be disposed along the longitudinal direction of the superconducting cable, and may be wound so as to surround the core part 100 outside, specifically, the heat insulating part 400 in a spiral or circular shape.

The number of the spacers 560 is a superconducting cable to which the superconducting wire is applied according to the present invention may be provided with three to five spacers. The spacer may form a spaced space to prevent heat exchange by conduction, and the structure of the spacer may be configured as a single layer or a plurality of layers.

The spacer 560 may be made of various resin materials, for example, polyethylene (PE).

In addition, the spacer 560 may be made of a fluorine resin (for example, Poly Tetra Fluoro Ethylene, Teflon (trade name)) material, or a general resin (for example, polyethylene) as necessary. The surface may be coated with a fluororesin (eg, fluorinated polyethylene).

Fluorinated polyethylene is a kind of fluororesin, which forms a very stable compound due to the strong chemical bonding of fluorine and carbon, and has almost perfect chemical inertness and heat resistance, non-tackiness, excellent insulation stability, and low coefficient of friction.

In addition, since the fluorinated polyethylene has a certain degree of flexibility, the insulation portion 400 may be spirally wrapped to be wound in the longitudinal direction of the superconducting cable, and the insulation portion 400 may have a certain strength. It can be used as a separation means for preventing the contact of the external metal tube 600 and may serve to physically maintain the separation space constituting the vacuum unit 500. The spacer 560 may have a diameter of 4 millimeters (mm) to 8 millimeters (mm). The cross-sectional shape of the spacer 560 may be various shapes such as a circle, a triangle, a rectangle, and a star.

An outer metal tube 600 may be provided outside the vacuum part 500 provided with the spacer 560. The outer metal tube 600 may be formed of the same shape and material as the inner metal tube 300, and the outer metal tube 600 is configured to have a larger diameter than the inner metal tube 300 and is formed through the spacer 560. It may be possible to form a space apart. Detailed description of the spacer 560 will be deferred later.

In addition, an outer jacket 700 may be provided at an outer side of the outer metal tube 600 to perform an outer function to protect the inside of the superconducting cable. The outer jacket may be a sheath material constituting the outer jacket 700 of a conventional power cable. The outer jacket 700 may prevent corrosion of the metal tube 600 therein and prevent cable damage due to external force. It may be made of a material such as polyethylene (PE) polyvinyl chloride (PVC).

3 shows an example of a superconducting wire rod that can be applied to a superconducting cable. Specifically, FIG. 3 (a) shows a cross-sectional view of a conventional superconducting wire 131 'which is not provided with a conducting layer, and FIG. 3 (b) shows a superconducting wire with a conducting layer made of a metal material having room temperature conduction. 131 is shown.

Since the superconducting wire constituting the superconducting cable is spirally wound along the longitudinal direction of the superconducting cable, the torsional stress is continuously applied, so that the superconducting wire may be broken during the manufacturing or winding of the superconducting cable. As described above, the former 110 is used as the return conductor in the event of an accident such as a short circuit (chatch, lightning, breakdown, breakdown of superconducting conditions, etc.).

The superconducting wire according to the present invention is provided with a conducting layer (me1, me2) of a metallic material having room temperature conduction on both surfaces to provide an effect of reinforcing the mechanical stiffness of the superconducting wire itself, and at the same time the conducting layer in the event of a short circuit accident of the superconducting system ( Since the me1 and me2 perform the function of the conductor with the ear, the diameter of the former can be reduced compared to the superconducting cable to which the superconducting wire without the conducting layer (me1, me2) is applied. The effect can be reduced. Review in detail.

The conventional superconducting wire shown in FIG. 3 (a) has a width x (mm) and a thickness of y (mm), and the superconducting wire according to the present invention shown in FIG. 3 (b) has both surfaces of a conventional superconducting wire. The conductive layers me1 and me2 made of a metal material and having a width x (mm) and a thickness y (mm) to 2 y (mm) are added thereto.

Accordingly, the superconducting wire 131 according to the present invention is provided with a conductive layer having a thickness of y (mm) to 2 y (mm) in the existing superconducting wire 131 ', and the overall thickness is 3y (mm) to 5y (mm). It can be composed of).

The superconducting wire used in the experiments described later used a superconducting wire having a width of 0.4 millimeters (mm) to 0.5 millimeters (mm) and a thickness of 0.3 millimeters (mm) to 0.5 millimeters (mm), that is, y = 0.1.

The conductive layer may be soldered as described below and added to the existing superconducting wire.

When the conductive layers me1 and me2 are soldered and added to both surfaces of the existing superconducting wire 131, the side surfaces of the superconducting wire 131 are soldered or the surface of the entire superconducting wire 131 is metal-coated, such as a short circuit. In the event of an accident, the fault current is classified into the conduction layer side added to each superconducting wire in addition to the wires of the former 110 connected in parallel with each superconducting wire 131, so that the conducting layers me1 and me2 are together with the former. Can share the role of

In addition, each of the conductive layers me1 and me2 has a width of x (mm) and a thickness of y (mm) to 2 y (mm), but the two surfaces of the superconducting wire having a conventional thickness of y (mm), respectively. Since it is added, the current carrying capacity may be greater according to the skin effect than when only one conductive layer having 2 y (mm) to 4 y (mm) is added to one surface of the existing superconducting wire.

When the conductive layer is added to both surfaces of the superconducting wire, rather than adding the conductive layer only to one surface of the superconducting wire, the separation of the conductive layer can be minimized and the stiffness can be reinforced when bending the superconducting wire. Even when using a furnace conduction layer, it may be advantageous to add the conduction layer to both surfaces of the superconducting wire and to reduce the diameter of the former.

Here, when the thickness of the existing superconducting wire is about 0.1 millimeters (mm), each conductive layer is about 0.1 millimeters (mm) to 0.2 millimeters (mm), the thickness of the superconducting wire of the superconducting wire according to the present invention is 0.3 It is composed of millimeter (mm) to 0.5 millimeter (mm), and the thickness of the superconducting wire is considerably increased compared to the existing superconducting wire, but the thickness of the improved superconducting wire is also thin film level, so it does not affect the overall thickness of the superconducting cable. As described above, the cross-sectional area of the former in which the non-insulated element wires are formed in a dense form may be reduced by about 10% to 40%.

The superconducting wire according to the present invention has a width of 0.4 millimeters (mm) to 0.5 millimeters (mm) and a thickness of 0.3 millimeters (mm) to 0.5 millimeters (mm), and YBCO or ReBCO (Re = Sm, Gd, Nd) as a superconducting material. , Dy, Ho) is used, the threshold current (DC Ic) at a temperature of 77K, 1 atm, self-field may be 150A to 500A.

4 is a cross-sectional configuration of the superconducting wires according to the present invention.

Specifically, Figure 4 (a) shows a cross-sectional view of one embodiment of a superconducting wire rod applicable to the superconducting wire according to the present invention, Figure 4 (b) shows a cross-sectional view of another embodiment of the superconducting wire.

For convenience of explanation, the superconducting wire 131 constituting the superconducting conductor layer will be described as an example.

The superconducting wire according to the present invention may be a first generation superconducting wire or a second generation superconducting wire.

The phenomenon that the electrical resistance becomes '0' below a certain temperature is called superconductivity, and it shows superconductivity at a relatively high temperature relative to absolute temperature near 100K (-173 ℃) instead of absolute 0K (-273 ℃). This is called a high temperature superconductor. The superconducting wire used in the field of power cable uses high temperature superconductor. Recently, the second generation wire of Coated Conductor (CC) type was introduced based on YBCO or ReBCO. Second generation superconducting wire refers to a superconducting wire in which the superconducting material provided in the deposition layer of the superconducting wire is mainly YBCO or ReBCO (Re = Sm, Gd, Nd, Dy, Ho) materials.

Referring to the second generation superconducting wire in detail, the second generation superconducting wire may include a metal substrate layer, a deposition layer, a silver (Ag) layer, and the like. The metal substrate layer is used as a base member of the wire rod, serves to maintain the mechanical strength of the superconducting wire rod, and Hastelloy, Nickel-Tungsten (Ni-W), and the like may be used. The deposition layer may include a buffer layer for depositing a superconducting layer on a metal substrate, a superconducting layer, and may include a superconducting layer used as a conduction path for current during energization.

The silver (Ag) layer may be composed of a silver (Ag) or copper (Cu) alloy layer, and the silver (Ag) alloy layer may be located between the superconducting layer and the copper (Cu) alloy layer to enable deposition. In addition, the copper (Cu) alloy layer may serve to reinforce mechanical strength. Each alloy layer can be configured in a different thickness and material according to the application, and has the characteristic of room temperature conduction.

Superconducting wire according to the present invention shown in FIG. 4 is a second generation superconducting wire, a superconducting wire using a metal substrate layer made of Hastelloy, nickel-tungsten (Ni-W) material may be used. An example is shown where two kinds of superconducting wires are applied.

The superconducting wire according to the present invention has a width of 0.4 millimeters (mm) to 0.5 millimeters (mm) and a thickness of 0.3 millimeters (mm) to 0.5 millimeters (mm), and YBCO or ReBCO (Re = Sm, Gd, Nd) as a superconducting material. , Dy, Ho) is used, the temperature of 77K, 1 atm, the critical current (DC Ic) in the self-field can be 150A to 500A, where the self-field is It means the magnetic field environment generated by electric current.

The critical current may be measured every 0.5 m to 1 m intervals of the superconducting wire to be measured by the continuous measuring method. In this case, the threshold current refers to the maximum current (before the short-circuit such as a quench) that can flow by applying a continuous DC voltage (DC).

FIG. 4A illustrates a superconducting wire 131 using a YBCO-based superconducting material, and FIG. 4B illustrates a cross-sectional view of the superconducting wire 131 using a ReBCO-based superconducting material.

The material of the metal substrate layer 1311 constituting the superconducting wire 131 shown in FIG. 4A may be a nickel-tungsten (Ni-W) alloy, and the metal substrate layer 1311 may be a metal tape. It may be configured in the form.

A deposition layer including a plurality of buffer layers 1312, 1313, and 1314 and a superconducting layer 1315 made of YBCO may be provided on the metal substrate layer 1311 formed of the nickel-tungsten (Ni-W) alloy material. Can be.

 In the embodiment shown in FIG. 4A, three buffer layers 1312, 1313, and 1314 are deposited. Specifically, each layer constituting the buffer layer is made of a material made of Y 2 O 3, YSZ, CeO 2, or the like. Can be configured. A superconducting layer 1315 made of YBCO material is deposited on each buffer layer, and an Ag layer is provided as an Ag layer 1316 on the outside of the superconducting layer 1315 for the purpose of protecting the superconducting wire. Can be.

The conductive layers me1 and me2 made of metal may be provided on the upper and lower portions of the superconducting wire 131 illustrated in FIG. 4A, that is, the outer side of the substrate layer 1311 and the silver layer 1316. have.

The reason why the conductive layers me1 and me2 are provided on both sides of the superconducting wire 131 is that physical stiffness reinforcement is strengthened than when the conductive layer is provided on only one side, and the variation of physical properties according to the bending direction is minimized. In order to increase the capacity as a conductor by the ear as described above.

In addition, the superconducting wire 131 constituting each of the superconducting conductor layer or the superconducting shielding layer is implemented on the premise that the superconducting conditions are maintained, but the conduction function according to the design capacity is implemented, but if the superconducting conditions are destroyed due to system problems, etc. The current flowing through the superconducting wire 131 is configured to be energized through the former, and the diameter of the former or the number of conductor wires may be determined according to the capacity for energizing the accident current.

However, since the diameter of the former 110 occupies a large proportion of the diameter of the entire superconducting cable, the diameter of the former to reduce the diameter of the former to reduce the total diameter or weight of the superconducting cable may be reduced.

Accordingly, as shown in FIG. 4, the conductive layers me1 and me2 made of metal, for example, brass, are provided on the upper and lower portions of the superconducting wire 131 to reinforce the rigidity of the superconducting wire 131. At the same time, it can be used as a conductor of the fault current and minimize the diameter of the former.

The conductive layers me1 and me2 of the metal material may be configured in the form of a metal thin film layer, and specifically, may be made of brass.

Brass refers to an alloy made by adding zinc to copper, and the conductive layer may be replaced with a copper alloy having good electrical conductivity other than brass.

In the following description, the conductive layer made of brass is preferably understood to include a copper alloy other than brass.

The conductive layers me1 and me2 of the metal material of brass may be added in the form of a metal thin film layer such as brass, and the brass mesh layer may have a thickness of 0.1 millimeter (mm) to 0.2 millimeter (mm). If it is assumed that the thickness of the conductive layer (me) of the metal material in the form of a brass tape attached to one side of the superconducting wire 131 is 0.125 millimeters (mm), the thickness of the entire superconducting wire 131 is about 0.4 millimeters (mm) Can be enough.

If the thickness of the metal conduction layer provided on at least one side of the superconducting wire 131 is 0.1 mm or less, sufficient rigidity reinforcement of the superconducting wire is difficult, and if it is 0.2 mm or more, the conducting layer when bending It has been confirmed that a problem may occur in which a conductive layer of a metal is separated from one surface of the provided superconducting wire 131 and an excessively thick thickness of the entire superconducting wire 131 provided with the conductive layer.

In one embodiment, the superconducting wire 131 has a thickness of about 0.1 millimeter (mm) and a thickness of 0.35 millimeter (mm) by attaching a conductive layer of metal material in the form of a brass tape having a thickness of 0.125 millimeter (mm) to both sides. 3 to 4 times, but the total thickness is small enough to be less than 1 millimeter (mm), so the effect on the overall thickness of the superconducting cable is insignificant, but the stiffness of the superconducting wire 131 is reinforced, and the return conductor of the accident current is As a result, the diameter or weight of the former can be reduced.

In other words, since the conductive layers me1 and me2 made of brass as metal thin layers are provided on the upper and lower portions of the superconducting wire 131, the rigidity of the superconducting wire 131 can be reinforced and the diameter or weight of the former can be reduced. When the conducting layer having a predetermined thickness is provided on both the outer side of the metal substrate layer constituting the superconducting wire 131 and the outer side of the silver (Ag) layer, the conducting layer is not provided on the superconducting wire 131. It means that the diameter or weight of the former can be reduced than if not.

As described above, the current flowing through the superconducting layer of the deposition layer 1315 when the accidental current is generated in the state in which the conducting layers me1 and me2 are attached to both sides of the superconducting wire 131 by solder or the like is applied to the conducting layer me1. In order to flow to me2), the superconducting wire 131 and the conductive layers me1 and me2 attached thereto must be electrically connected.

Accordingly, the conductive layers me1 and me2 attached to both sides of the superconducting wire 131 and the superconducting wire 131 are connected in parallel to each other for energizing an accident current, and the superconducting wire 131 and the superconducting wire 131 are respectively connected. Although not shown in FIG. 4, a method of electrically connecting the conductive layers me1 and me2 attached to both sides of the conductive layer may be soldered to the side of the superconducting wire 131 with a metal base solder or the superconducting wire 131 may have good electrical conductivity. A method of plating with a metal such as copper (Cu) may be used.

In both methods, the conductive layers me1 and me2 and the superconducting wire 131 may be electrically connected to each other while minimizing the increase in the thickness or volume of the superconducting wire 131 to which the conductive layers me1 and me2 are attached.

In addition, the metal substrate layer 1311 constituting the superconducting wire 131, the deposition layers 1312 to 1315 including the superconducting layer, and the silver (Ag) layer 1316 are electrically formed by copper plating or side soldering. When connected in parallel with each other, the superconducting layer 1315 is electrically connected to the metal substrate layer 1311, the silver (Ag) layer 1316 and the respective conducting layers me1 and me2, and the fault current is the conducting layer me1. In addition to me2, the metal substrate layer 1311 and the silver (Ag) layer 1316 may be classified.

The conductive layers me1 and me2 as the metal thin film layers may be soldered and attached to the superconducting wire 131. Solder for soldering the conductive layers me1 and me2 to both sides of the superconducting wire 131 is composed of tin (Sn), lead (Pb), and silver (Ag), and has a melting point of 200 ° C. or less. Can be. However, in addition to the solder material described above, various solders may be applied to the metal substrate layer 1311 or silver (Ag) layer 1316 constituting the conductive layers me1 and me2 and the superconducting wire 131. Alternatively, the attachment method may be applied.

4 (b) shows a superconducting wire 131 'using ReBCO-based superconducting material. The description overlapping with the description with reference to FIG. 4 (a) will be omitted.

The material of the metal substrate layer 1311 ′ constituting the superconducting wire 131 ′ shown in FIG. 4B may be a nickel-tungsten (Ni-W) alloy, and the metal substrate layer 1311 ′ may be a metal. The same may also be configured in the form of a thin film layer.

At least six buffer layers 1312 ', 1313', 1314 ', 1315', and 1316 'formed on the metal substrate layer 1311' formed of the nickel-tungsten (Ni-W) alloy material and the ReBCO-based Deposition layers 1312 'to 1317' comprising a superconducting layer of 1317 'are provided, and outside the deposition layer deposition layers 1312' to 1317 'are silver (Ag) layers 1318'. ) Layer may be provided.

Each seed layer constituting the buffer layers 1312 ', 1313', 1314 ', 1315', and 1316 'may be composed of Al2O3, Y2O3, IBAD-MGo, EPI-MGo, and LaMoO3 layers.

The superconducting wire 131 ′ shown in FIG. 4 (b) is also provided with conductive layers me1 and me2 outside the metal substrate layer 1311 ′ and the silver (Ag) layer 1318 ′, respectively. Like the superconducting embodiment shown in a), it can be used for physical stiffness reinforcement and fault current classification.

As described above, the diameter of the former to serve as a conductor of the accident current by forming an energization layer composed of a metal thin film layer made of brass or the like on both sides of the superconducting wire 131 'and using it as a means of energizing the accident current. Can be reduced.

Of course, although the metal substrate layer and silver (Ag) layer constituting the superconducting wire 131 ′ shown in FIG. 4 are also made of a metallic material, there is a bypass function of the fault current, but based on the thickness of the conventional superconducting wire Due to the small cross-sectional area occupied by the metal substrate layer and the silver (Ag) layer, the bypass capacity of the fault current was minimal.

However, as described above, since the metal conductive layers me each have a thickness of about 0.125 millimeters (mm), the amount of energization through them may affect the diameter of the former for returning to the accident current. Is as described above.

Therefore, when the diameter of the former is designed, the current carrying amount of the accident current through the metal substrate layer and the silver (Ag) layer is considered, including a metal conduction layer (me) of the superconducting wire 131 'constituting the superconducting conductor layer. It is possible to set the diameter of the former to be reduced than before. The maximum allowable amount of current can be determined by the thermal analysis method according to the energization of the accident current through the metal conduction layer (me), the metal substrate layer, and the silver (Ag) layer of the superconducting wire, thereby reducing the diameter of the former. Can be designed.

Figure 5 shows a test facility for the bending test of the superconducting wire according to the present invention. Specifically, FIG. 5 (a) shows equipment for measuring the threshold current when applying the bending stress, and FIG. 5 (b) shows the equipment for measuring the threshold current when applying the double banding stress.

The threshold current when the bending stress is applied is measured by bending the superconducting wire 131 in different directions via two rollers, and the threshold current when the double bending stress is applied to the superconducting wire 131 in different directions. It can be bent to measure the critical current via the two rollers.

In the superconducting wire according to the present invention, when the thickness of the superconducting wire 131 to which conductive layers me1 and me2 of brass are added is configured as 3y to 5y, as shown in FIG. The tensile strength of the superconducting wires to which the conducting layers (me1 and me2) were added as the metal thin film layer was found to be 200 megapascals (Mpa) to 800 megapascals (Mpa) based on 95 percent current attenuation (IC relentation). It was confirmed that sufficient stiffness can be secured when winding on cables.

The 95 percent IC relentation criterion is a test method for measuring the tensile force until a 95 percent current amount of initial conduction is obtained while gradually increasing the tensile force at both ends of the superconducting wire, and thus 200 megapascals (Mpa) to 800 mega This means that even when a Pascal (Mpa) tensile force is applied to the superconducting wire, at least 95 percent of electricity can be secured. This condition means that the test method measured using the test method shown in FIG. 5 or the like in another aspect can also be passed. That is, the physical or electrical properties required in the following description are methods for determining the stress condition in advance and examining whether or not the threshold current at that time satisfies 95% of the threshold current of the normal superconducting wire.

As shown in Fig. 5 (a), after bending the superconducting wire with a metal layer layer according to the present invention by using two rollers (r1, r2) having a diameter of 35 millimeters (mm) sequentially and bending The critical current during banding stress satisfies more than 95 percent of the threshold current of the superconducting wire without banding stress.

In addition, as shown in Figure 5 (b), the superconducting wire with a metal layer layer according to the present invention in sequence using four rollers (r1, r2, r3 and r4) having a diameter of 50 millimeters (mm) The double-banding threshold current after bending with direction change satisfies more than 95 percent of the threshold current of the superconducting wire without any bending stress applied.

As described above, the superconducting wire according to the present invention should be provided with a metal layer to ensure sufficient physical rigidity in the manufacturing or laying process of the superconducting cable, and in addition to the bending stress, the tensile stress or the torsional stress may be applied even when the stress is applied. Over 95 percent of the critical current of an unstressed superconducting wire can be met.

Specifically, in the superconducting wire according to the present invention, the tensile threshold current when the 250 MPa longitudinal tensile force or the longitudinal tensile force that is 0.2% elongated may be 95% or more of the threshold current, and the length of the superconducting wire according to the present invention. The torsional threshold current in the twisted state at intervals of 200 millimeters (mm) in the direction may be at least 95 percent of the threshold current.

In addition, the torsional threshold current in the state in which the superconducting wire according to the present invention is twisted at intervals of 200 millimeters (mm) in the longitudinal direction with respect to the torsion stress is preferably 95% or more of the threshold current of the torsional superconducting wire.

The superconducting wire 131 is generally preferably connected three times or less in order to reduce the connection resistance at a distance within 1 km. Therefore, the superconducting wire is bonded in units of 200 meters (m) to 400 meters (m), and the resistance at one junction may be 200 nΩ or less (100 nΩ to 200 nΩ).

In addition, the AC loss of the superconducting wire according to the present invention is preferably 0.4 W / kA * m or less. AC loss here means that the loss of 1kA AC current in a 1m long superconducting wire should be 0.4 W or less. This defines the range of ac losses for a single superconducting wire, not for superconducting cables.

Furthermore, it is preferable that the threshold current condition and the resistance condition at the junction site of the same reference are satisfied even when the tensile force and the torsion are applied simultaneously.

The superconducting wire according to the present invention should be longitudinally bonded along the longitudinal direction of the cable and the bonding resistance at each bonding site may be 200 nΩ or less. This joint resistance is based on the assumption that the superconducting wire is measured without mechanical stress, and the resistance at each joint does not increase by more than 20 percent even when the superconducting wire is tensioned and wound on the former of the superconducting cable. It is preferable.

In conclusion, the joint resistance is 240 nΩ even when the superconducting wire is wound around 220 millimeters (mm) in the former of the superconducting cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire. It is preferable to measure below or to increase to 20 percent or less than the steady state junction resistance.

The critical current of the superconducting wire against such physical stress must satisfy the electrical characteristics of about 95 percent or more of the critical current of the superconducting wire without stress to ensure the durability and electrical conductivity of the superconducting wire during the manufacturing or laying of the superconducting cable. can do.

6 shows a voltage graph according to the current flowing in the superconducting wire.

The threshold current refers to the maximum current (before a short circuit such as a quench) that can flow by applying a continuous DC voltage (DC). Therefore, when a current of more than a threshold current is energized, the resistance increases rapidly and the voltage also increases rapidly. Therefore, it is not preferable that the rate of increase of the voltage is too large.

In the second generation superconducting wire according to the present invention, it is preferable that the slope of the voltage with respect to the current above the threshold current satisfies the range of 25 to 30. The slope n can be naturally measured by measuring a critical current.

7 shows a hermeticity test facility of the superconducting wire according to the present invention.

The airtightness of the superconducting wire means that the superconducting wire does not swell and maintains its original form while the superconducting wire is immersed in high pressure liquid nitrogen, and the critical current of the predetermined range is guaranteed.

As shown in FIG. 7, the liquid nitrogen (L) is filled in the metal tube (S) on which the superconducting wire 131 is disposed, and the external pressure is applied so that the internal pressure of the metal tube (S) is about 30 atm. After maintaining the state in which the pressure is applied to the inside of the metal tube S with gas nitrogen for about 16 hours, a visual inspection of the ballooning of the superconducting wire and a method of measuring the critical current may be used.

Under these test conditions, it can be judged that the superconducting wire satisfies the airtight condition if the visual inspection does not swell and the threshold current maintains about 95 percent of the normal threshold current.

Although the present specification has been described with reference to preferred embodiments of the invention, those skilled in the art may variously modify and change the invention without departing from the spirit and scope of the invention as set forth in the claims set forth below. Could be done. Therefore, it should be seen that all modifications included in the technical scope of the present invention are basically included in the scope of the claims of the present invention.

Claims (15)

1. 0.4 millimeters (mm) to 0.5 millimeters (mm) wide and 0.3 millimeters (mm) to 0.5 millimeters (mm) thick, used as superconducting material by YBCO or ReBCO (Re = Sm, Gd, Nd, Dy, Ho) In the superconducting wire

   Superconducting wire, characterized in that the temperature of 77K, 1 atm, self-field threshold current (DC Ic) is 150A to 500A.
2. The method of claim 1,

   The superconducting wire is a superconducting wire, characterized in that by using two rollers having a diameter of 35 millimeters (mm) in order to change the direction sequentially and the bending current after the bending is applied, the threshold current is 95% or more of the threshold current.
3. The method of claim 1,

   The superconducting wire is characterized in that the threshold current at the time of applying the double-banding stress after bending and bending the superconducting wire in sequence using four rollers having a diameter of 50 millimeters (mm) is 95% or more of the threshold current.
4. The method of claim 1,

   The superconducting wire is a superconducting wire, characterized in that the tensile critical current is applied when the longitudinal tensile force of 250MPa longitudinal tension or 0.2% elongation is more than 95% of the threshold current.
5. The method of claim 1,

   A torsional threshold current in a state where the superconducting wire is twisted at intervals of 200 millimeters (mm) in the longitudinal direction is at least 95 percent of the threshold current.
6. The method of claim 1,

   When the superconducting wire is wound around 220 mm (mm) in pitch to the former of the superconducting cable, and the load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire, the threshold current is 95% or more of the threshold current. Superconducting wire made of.
7. The method of claim 1,

   The superconducting wire is bonded in 200 meters (m) to 400 meters (m) units, the resistance of the junction portion is a superconducting wire, characterized in that less than 200n 200.
8. The method of claim 7, wherein

   The joint resistance is 240 nΩ or less for each joint site where the superconducting wire is wound around 220 millimeters (mm) in the former of the superconducting cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire. Superconducting wire, wherein the superconducting wire is increased by 20 percent or less than the steady state joint resistance.
9. The method of claim 1,

   The superconducting wire, characterized in that the critical current in the state of immersing the superconducting wire for 16 hours in liquid nitrogen at an internal pressure of about 30 atm is more than 95 percent of the critical current.
10. The method of claim 1,

    A superconducting wire rod, characterized in that the superconducting wire rod swelling of the superconducting wire rod in the state of immersing the superconducting wire rod in liquid nitrogen maintained at about 30 atm for 16 hours is not visually observed.
11. The method of claim 1,

    Superconducting wire, characterized in that the slope of the voltage with respect to the current above the threshold current 25 to 30.
12. The method of claim 1,

    AC loss of the superconducting wire is superconducting wire, characterized in that less than 0.4 W / kA * m.
13. 0.4 millimeters (mm) to 0.5 millimeters (mm) wide and 0.3 millimeters (mm) to 0.5 millimeters (mm) thick, used as superconducting material by YBCO or ReBCO (Re = Sm, Gd, Nd, Dy, Ho) In the superconducting wire

    77K temperature, 1 atmosphere, the critical current (DC Ic) in the self-field is 150A to 500A or less,

    When bending stress is applied after bending the superconducting wire by sequentially changing the direction using two rollers having a diameter of 35 mm (mm),

    When the double-bending stress is applied after bending the superconducting wire rod sequentially by using four rollers having a diameter of 50 millimeters (mm),

    When 250 MPa longitudinal tension or 0.2% elongation is applied to the superconducting wire,

    Twisting the superconducting wire at intervals of 200 millimeters (mm) in the longitudinal direction, or

    When the superconducting wire is wound around 220 millimeters (mm) in the former of the superconducting cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire or the internal pressure of the superconducting wire is maintained at about 30 atmospheres. The threshold current in 16 hours of immersion in liquid nitrogen satisfies 95% or more of the threshold current,

    The superconducting wire is joined in a unit of 200 meters (m) to 400 meters (m), the resistance of the junction is less than 200nΩ, the junction resistance is pitch of about 220 millimeters (mm) around the superconducting wire to the former of the superconducting cable Winding resistance and the joint resistance of each joint area where 3 kg ~ 8 kg load is applied in the longitudinal direction of the superconducting wire becomes 240 nΩ or less, or increases to 20 percent less than the steady state joint resistance,

    The slope of the voltage with respect to the current above the threshold current is 25 to 30,

    AC loss is less than 0.4 W / kA * m superconducting wire, characterized in that.
14. 0.4 millimeters (mm) to 0.5 millimeters (mm) wide and 0.3 millimeters (mm) to 0.5 millimeters (mm) thick, used as superconducting material by YBCO or ReBCO (Re = Sm, Gd, Nd, Dy, Ho) In the superconducting wire

    A superconducting wire rod, characterized in that the superconducting wire rod swelling of the superconducting wire rod in the state of immersing the superconducting wire rod in liquid nitrogen maintained at about 30 atm for 16 hours is not visually observed.
15. 0.4 millimeters (mm) to 0.5 millimeters (mm) wide and 0.3 millimeters (mm) to 0.5 millimeters (mm) thick, used as superconducting material by YBCO or ReBCO (Re = Sm, Gd, Nd, Dy, Ho) In the superconducting wire

    77K temperature, 1 atmosphere, the critical current (DC Ic) in the self-field is 150A to 500A or less,

    When bending stress is applied after bending the superconducting wire by sequentially changing the direction using two rollers having a diameter of 35 mm (mm),

    When the double-bending stress is applied after bending the superconducting wire rod sequentially by using four rollers having a diameter of 50 millimeters (mm),

    When 250 MPa longitudinal tension or 0.2% elongation is applied to the superconducting wire,

    Twisting the superconducting wire at intervals of 200 millimeters (mm) in the longitudinal direction, or

    When the superconducting wire is wound around 220 millimeters (mm) in the former of the superconducting cable and a load of 3 kg to 8 kg is applied in the longitudinal direction of the superconducting wire or the internal pressure of the superconducting wire is maintained at about 30 atmospheres. The threshold current in 16 hours of immersion in liquid nitrogen satisfies 95% or more of the threshold current,

    The superconducting wire is joined in a unit of 200 meters (m) to 400 meters (m), the resistance of the junction is less than 200nΩ, the junction resistance is pitch of about 220 millimeters (mm) around the superconducting wire to the former of the superconducting cable Winding resistance and the joint resistance of each joint area where 3 kg ~ 8 kg load is applied in the longitudinal direction of the superconducting wire becomes 240 nΩ or less, or increases to 20 percent less than the steady state joint resistance,

    The slope of the voltage with respect to the current above the threshold current is 25 to 30,

    AC loss is 0.4 W / kA * m or less

    A superconducting wire rod, characterized in that the superconducting wire rod swelling of the superconducting wire rod in the state of immersing the superconducting wire rod in liquid nitrogen maintained at about 30 atm for 16 hours is not visually observed.

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