KR20170009253A - Superconducting cable - Google Patents

Abstract

The present invention relates to a superconductive cable. The present invention secures a separation state of a vacuum part equipped for vacuum insulation and minimizes heat invasion of the outside through conduction through a spacer installed on the vacuum part. The present invention includes: a core part having a superconductive layer, an insulation layer, and a superconductive shielding layer; a metal pipe; and an insulation part.

Description

Superconducting cable {SUPERCONDUCTING CABLE}

The present invention relates to a superconducting cable. More particularly, the present invention relates to a superconducting cable capable of minimizing external heat penetration due to conduction through a spacer provided on a vacuum stage, while maintaining a vacuum state for vacuum insulation.

The superconducting wire has a large power transmission capability even at a low voltage since the electric resistance converges near zero at a constant temperature.

In order to form and maintain a cryogenic environment, a superconducting cable having such a superconducting wire uses a method of cooling using a coolant such as nitrogen and / or an adiabatic method of forming a vacuum layer.

Such a superconducting cable generally includes a superconducting conductor layer composed of superconducting wires for power transmission, and a superconducting shielding layer for shielding electromagnetic waves induced by the superconducting conductor layer. The superconducting shield layer is formed of an expensive superconducting wire as well as the superconducting conductor layer.

That is, the electromagnetic wave induced by the power transmitted from the superconducting conductor layer can be shielded through the superconducting shielding layer.

The BSCCO first-generation superconducting wire can be manufactured by a relatively simple machining method. However, due to the crystal orientation characteristics of BSCCO (Bi-2223, Bi-2212) superconducting wire, the critical current density Jc at 77 K, the 100,000 limit in improving the a / cm ² or more, and difficult to because of high cis substance Ag price of the wire is at cost configured to lower the performance-to-price, in recent years the production and use of the first generation of superconducting tape were reduced.

On the other hand, the second-generation superconducting wire is a coated conductor in which oxide films are deposited in layers on a metal substrate.

The second generation superconducting wire of YBCO or REBCO system has a high critical current characteristic in the magnetic field and a much higher tensile current density than the first generation BSCCO wire, so it can replace the first generation high temperature superconducting wire from the early 1990s Various fabrication processes have been actively developed with the attention as a next generation superconducting wire.

In order to use superconducting system's advantage that superconductor's resistance converges to zero at cryogenic temperature and can transmit a large amount of current even at relatively low voltage, superconducting cable The cryogenic environment of the superconductor should be ensured.

Therefore, in order to form a cryogenic temperature, which is a superconducting condition of a superconductor, a superconducting cable has a cooling part for flowing a liquid coolant through a cooling channel on the outside of the core part, further forming a vacuum on the outside of the cooling part, The superconducting condition of the superconductor can be maintained.

In this case, the cooling section formed by the cooling flow passage is partitioned by the inner metal tube, and the insulating section provided with the heat insulating material for preventing the heat penetration is provided outside the inner metal tube.

A vacuum part for blocking heat penetration by convection in a vacuum space provided with a spacer is provided on the outer side of the heat insulating part, and the vacuum part is partitioned by an outer metal pipe 600.

A method of forming a vacuum in a superconducting cable includes securing a space for forming a vacuum and providing a plurality of spacers in the space to form an inner surface and an outer surface of the space, And the inner surface of the outer metal pipe 600 can be prevented from being in contact with each other.

Such a spacer can physically form a spacing space to form a vacuum, but the amount of heat penetration due to heat conduction through the spacer itself is not so small.

8 is a cross-sectional view of a conventional superconducting cable in a state in which it is installed in a horizontal direction. The conventional superconducting cable includes a superconducting cable including a former 110, a superconducting conductor layer 130 surrounding the former 110, an insulating layer 140 surrounding the superconducting conductor layer 130, an insulating layer 140, A core portion 100 including at least one superconducting shield layer 180 surrounding the core portion 100, a cooling portion 200 for cooling the core portion 100, an inner metal tube (not shown) provided outside the cooling portion 200, A spacer 560 is formed on the inner side of the inner metal tube 300 and the inner surface of the inner metal tube 300 is connected to the outer surface of the inner metal tube 300, May be provided.

The inner surface of the outer metal pipe 600 can be prevented from being in direct contact with the heat insulating part 400 by the spacer 560 provided in the vacuum 500. [ Heat penetration from the outside room temperature to the inside can occur in the form of convection, radiation and conduction, and the heat penetration by the convection can be prevented or minimized through the vacuum 500, The insulating material coated with the material may be cut off by the insulation part 400 wound plural times or the like.

The conventional superconducting cable uses a plurality of spacers to maintain the spacing between the heat insulating portion and the outer metal pipe 600 so as to block the contact between the heat insulating portion and the outer metal pipe 600 that partition the inside and the outside of the vacuum chamber And the heat penetration through the spacer is also increased in proportion to the number of spacers. Therefore, it is not preferable that the spacers are shortened and the heat insulating portion and the external metal pipe 600 are in contact with each other to increase the heat intrusion. It is also undesirable to increase the heat penetration through the spacers when a plurality of spacers are provided.

Therefore, in order to reduce the heat penetration amount of the conventional superconducting cable, it is necessary to prevent the heat insulating part for partitioning the vacuum and the external metal pipe 600 from contacting each other, and to minimize heat penetration through the spacer itself.

The present invention provides a superconducting cable capable of minimizing external heat penetration due to conduction through a spacer provided on a vacuum chamber while ensuring a vacuum state for vacuum insulation for vacuum insulation. do.

According to an aspect of the present invention, there is provided a method of manufacturing a superconducting thin film transistor, comprising the steps of forming a superconducting layer on a substrate, forming a superconducting conductor layer on the outer side of the superconducting conductor layer, An inner metal tube having a circulating flow path for the liquid coolant for cooling the core portion; a heat insulating portion provided on the outer side of the inner metal tube and wound around the heat insulating material a plurality of times; (Mm) to 800 millimeters (mm) so as to prevent contact between the heat insulating portion and the outer metal pipe 600 on the outer side of the heat insulating material, A spacer, and an outer jacket surrounding the outer metal pipe 600. [0031] FIG.

Here, the weight per length of the superconducting cable may be 10 Kg / m to 12 Kg / m.

In addition, one of the spacers may be provided and the diameter of the spacer may be 5 millimeters (mm) to 7 millimeters (mm).

Further, the spacer may be composed of fluorinated polyethylenes.

The physical properties of the fluorinated polyethylene have a thermal conductivity of not more than 6 (10-4 cal / cm.sec. ° C) 6 according to ASTM C177, and a tensile strength according to ASTM test method of 175 kgf / cm ² or more, the elastic modulus may be greater than or equal to 3000kgf / cm ² or higher, the compression strength of 100 kgf / cm ^2.

The inner metal pipe or the outer metal pipe 600 has a corrugated bending structure in which the valley and the valley are repeatedly formed in a spiral manner and the winding direction of the spacer and the valley or the valley structure of the inner metal pipe or the outer metal pipe 600 May be different from each other.

According to another aspect of the present invention, there is provided a cooling system for a refrigerator including a core unit including a former, a superconducting conductor layer, and a superconducting shielding layer, A heat insulating part provided outside the cooling part to block heat penetration by radiation, a heat insulating part which surrounds the heat insulating part spirally and has a diameter of 5 mm to 7 mm and is made of a fluorinated polyethylene resin And an outer jacket surrounding the outer metal tube. The superconducting cable may include a plurality of spacers, a plurality of spacers, and a plurality of spacers.

According to the superconducting cable of the present invention, heat penetration through the spacers provided in the superconducting cable can be minimized.

In addition, according to the superconducting cable according to the present invention, the number of spacers provided in the vacuum chambers can be reduced and the pitch of the windings of the spacers can be optimized without additional or additional components, It is possible to effectively prevent the inner contact.

Further, according to the superconducting cable according to the present invention, heat penetration through the spacer can be minimized by reducing the number of spacers, optimizing the winding pitch of the spacers and the diameter of the spacers.

In addition, the superconducting cable according to the present invention minimizes heat penetration into the superconducting cable, minimizes the cooling load of the cooling system for cooling the superconducting cable, and improves the stability of the superconducting power system.

FIG. 1 shows a perspective view of a superconducting cable according to one embodiment of the present invention taken along a stepwise direction.
Fig. 2 shows a cross-sectional view of the superconducting cable shown in Fig. 1 in a horizontal direction.
Fig. 3 shows a longitudinal cross-sectional view of the lower portion of the superconducting cable shown in Figs. 1 and 2. Fig.
Fig. 4 is a graph showing the amount of heat loss over time when the winding pitch, which is the second verification example, is 300 millimeters (mm).
FIG. 5 is a perspective view of a superconducting cable according to another embodiment of the present invention.
Fig. 6 shows a cross-sectional view of the superconducting cable shown in Fig. 5 in a horizontally installed state.
Fig. 7 shows a cross-sectional view of a conventional superconducting cable.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification.

2 is a cross-sectional view of the superconducting cable shown in FIG. 1. FIG. 3 is a cross-sectional view of the lower portion of the superconducting cable shown in FIG. 1 and FIG. Fig.

The basic structure of a superconducting cable according to the present invention will be described.

The superconducting cable includes at least one superconducting conductor layer (130) including a former (110), a plurality of superconducting wires arranged side by side in the longitudinal direction of the former (110) so as to surround the former, Wherein at least one superconducting shield layer comprises a plurality of superconducting wires arranged in the longitudinal direction of the former 110 so as to surround the insulating layer 140 surrounding the insulating layer 140, A coolant passage for cooling the core portion 100 and a coolant passage for cooling the core portion 100. The core portion 100 includes a core portion 100 for cooling the core portion 100, The inner metal pipe 300 disposed outside the cooling unit 200 and the heat insulating member 401 disposed outside the inner metal pipe 300 to form a heat insulating layer wound in multiple layers, (400), and is spaced apart from the heat insulating portion (400) And an outer metal pipe 600 having an inner portion held in a vacuum state and a second outer metal pipe 600 having a winding pitch of 200 millimeters (mm) to prevent contact between the heat insulating portion and the outer metal pipe 600, A superconducting cable 1000 including a spacer 560 wound to be 800 mm and an outer jacket 700 surrounding the outer metal pipe 600 can be provided.

The components of the superconducting cable are summarized as follows. The former 110 functions as a frame for forming a shape while providing a place for mounting a flat, flat and long superconducting wire around the former 110, and can be a path through which a fault current flows. The former 110 may have a shape obtained by compressing a plurality of copper (Cu) strands 111 having a circular section in a round cylindrical shape or a pipe shape.

Specifically, the former 110 is basically formed into a round cylindrical or pipe shape, and serves as a frame for raising the flat, long superconducting wire. The diameter of the former 110 is determined to be as close to a circular shape as possible when the superconducting wire is placed on the former 110 between the superconducting wires without considering the width of the superconducting wire.

1 and 2, the former 110 may have a hollow shape, and the former 110 serves as a frame for raising the superconducting wire, and at the same time, And each of the strands 111 constituting the former may be constituted by copper or the like and each of the strands may be connected in parallel with the superconducting wire to cause a failure in the power system It may be configured to serve as a conductor to the ear when a current is generated.

Depending on the capacity of the fault current, the cross-sectional area of the conductor, such as copper, constituting the strand can be determined. In the case of high voltage, the strand of copper can be compressed into a circular shape to form a stranded shape.

The surface of the former 110 is inevitably convex because the strands 111 constituting the former 110 have a circular shape. Accordingly, a smoothing layer 120 may be coated on the outside of the former 110 to smooth the convex surface of the former 110. The smoothing layer 120 may be made of semiconductive carbon paper or brass tape.

Between the smoothing layer 120 and the superconducting conductor layer 130, a cushion layer may be further provided although not shown in the figure. The cushion layer may be provided to protect the superconducting conductor layer using a semi-conductive carbon paper tape.

A first superconducting conductor layer 130a may be provided on the outer side of the former 110 which is planarized by the smoothing layer 120 and is surrounded by a plurality of superconducting wires 131. The first superconducting conductor layer 130a may be installed so as to surround a plurality of superconducting wires adjacent to each other and around the smoothing layer 120. [

Also, as shown in FIG. 1, the superconducting conductor layer 130 may be formed in a multi-layer structure according to the capacity of a current to be transmitted or distributed through the superconducting cable.

The embodiment shown in FIG. 1 shows a total of two superconducting conductor layers 130a and 130b. Further, when the superconducting conductor layers are simply stacked and arranged, the current capacity does not increase according to the skin effect of the current. In order to prevent such a problem, when the superconducting conductor layer is provided in a multi-layer structure, an insulating layer 140 may be provided between the superconducting conductor layers 130a and 130b. The insulating layer 140 may be formed in the form of an insulating tape. The insulating layer 140 may be disposed between the superconducting layers 130a and 130b to isolate the superconducting layers 130a and 130b from each other. . The insulating layers 140 may coincide with the conducting directions of the superconducting conductor layers laminated in a multilayer structure.

In the embodiment shown in FIG. 1, the superconducting conductor layer 130 is composed of two layers of the first superconducting conductor layer 130a and the second superconducting conductor layer 130b. However, if necessary, A conductor layer may also be provided.

The superconducting wires constituting each of the superconducting conductor layers 130a and 130b may be connected in parallel with the respective superconducting wires constituting the former 110. [ So that the current flowing through the superconducting wire can flow to the wire of the former 110 in the event of an accident such as destruction of the superconducting condition. When the superconducting condition is not satisfied in this way, the resistance of the superconducting wire is increased and the heat or damage of the superconducting wire is prevented.

The inner semiconductive layer 150 may be provided outside the second superconducting layer 130b provided outside the first superconducting conductor layer 130a. The inner semiconductive layer 150 may be provided to alleviate field concentration of the superconducting layer 130 and to smooth the surface electric field. Specifically, it can be provided to alleviate the electric field concentration generated at the corner portion of the superconducting wire and to even out the electric field distribution. This also applies to the outer semiconductive layer 170 described later.

The inner semiconductive layer 150 may be provided in such a manner that the semiconductive tape is wound.

An insulating layer 160 may be provided outside the inner semiconductive layer 150. The insulation layer 160 may be provided to increase the dielectric strength of the superconducting cable. Generally, XLPE (Cross Linking-Polyethylene) or oil filled cable is used for insulation of high voltage cable. However, superconducting cable is cooled to cryogenic temperature for superconductivity of superconducting wire, and XLPE is broken at insulation And the oil filled cable may cause an environmental problem. Therefore, the superconducting cable according to the present invention may use insulating paper of a general paper as the insulating layer 160, May be configured in such a manner that the insulating paper is wound plural times.

Kraft paper or PPLP (Polypropylene Laminated Paper) is mainly used as the insulating paper. PPLP insulating paper is used for superconducting cable among various insulation materials considering the ease of winding and the dielectric strength.

The outer semiconductive layer 170 may be provided outside the insulating layer 160. The outer semiconducting layer 170 may also be provided in such a manner that the semiconducting tape is wound on the outer semiconducting layer 170. The outer semiconducting layer 170 may also be provided in order to alleviate the field concentration of the superconducting conductor layer 130 and to smooth the surface electric field. .

In addition, a superconducting shield layer 180 may be provided outside the outer semiconductive 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. If the surface of the outer semiconductive layer 170 is uneven, a smoothing layer (not shown) may be provided if necessary. A superconducting wire for forming the superconducting shield layer 180 on the outside of the smoothing layer may be provided in the circumferential direction As shown in FIG.

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

A core outer layer 190 may be provided on the outer side of the superconducting shield layer 180 to serve as a core of the core unit 100. The core outer layer 190 may include various tapes, binders, and the like. The core outer layer 190 serves to externally expose the core portion 100 to a cooling layer, which will be described later, and to bind all components of the core portion 100 And may be made of a metal tape such as SUS material.

1 and 2, the smoothing layer and the semiconductive layer are formed of a single layer of the same material, but it is also possible to use various sublayers 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 include a circulating flow path for liquid coolant inside the cooling unit 200. The liquid-phase refrigerant (liquid nitrogen) is circulated through the refrigerant passage in a state of being cooled to have a temperature of about minus -200 degrees, and the superconductivity The superconducting condition of the wire rod can be maintained.

The cooling channel provided in the cooling unit 200 may allow the liquid-phase refrigerant to flow in one direction, may be recovered from the connection box of the superconducting cable, re-cooled, and then supplied to the cooling channel of the cooling unit 200.

An inner metal pipe 300 may be provided outside the cooling unit 200. The inner metal pipe 300 functions as an outer casing of the superconducting cable for preventing the mechanical damage of the core part 100 during installation and operation of the superconducting cable together with the outer metal pipe 600 to be described later. The superconducting cable is wound on the drum for easy manufacture and transportation. When installed, the cable wound around the drum is expanded and installed, so that bending stress or tensile stress can be continuously applied to the superconducting cable.

An internal metal pipe 300 may be provided to maintain the initial performance even under such a mechanical stress. Therefore, the inner metal pipe 300 has a corrugation structure in which the corrugation and the floor are repeated (bulging and depressing repeatedly) in the longitudinal direction of the superconducting cable for reinforcing the rigidity against mechanical stress, 300 may be made of a material such as aluminum or stainless steel.

The bending performance and the rigidity can be improved as compared with the case where the metal pipe is formed in a smooth shape by the corrugation bending structure.

Since the inner metal pipe 300 defines the outside of the cooling unit 200, it may be a very low temperature 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 surface of the inner metal pipe 300 may be provided with a heat insulating part 400 including a heat insulating layer in which a heat insulating material coated with a thin polymer of a low thermal conductivity is wound on a metal film having a high reflectance. The heat insulating part 400 may be provided to prevent multi-layer insulation (MLI) from occurring due to radiation such as radiation to the inner metal pipe 300. The heat insulating part 400 may be made of a metal film material having high reflectance.

The number of layers of the heat insulating part 400 can be adjusted to minimize heat penetration. It is important to use the appropriate number of layers because the heat shielding effect is lowered by the convection heat blocking effect and the thinning of the vacuum layer due to the convection.

A vacuum 500 may be provided outside the heat insulating part 400. The vacuum chamber 500 may be provided to minimize heat transfer or heat penetration due to convection in the direction of the heat insulating part 400, which may be generated when the heat insulating part 400 does not sufficiently insulate the heat insulating part 400.

The vacuum chamber 500 can be formed by forming a space outside the heat insulating part 400 and vacuuming the space.

The vacuum chamber 500 constituting the superconducting cable according to the present invention may be provided with spacers to form a physical separation space to prevent heat penetration from the outside to the core side by convection or the like. .

Conventionally, a superconducting cable has been spirally wound around a plurality of spacers spaced apart from each other.

However, in the superconducting cable according to the present invention, one spacer 560 is applied to the vacuum 500, unlike the conventional superconducting cable.

That is, unlike the prior art, one spacer can be wound more tightly to prevent the inner surface of the heat insulating portion 400 from contacting the inner surface of the outer metal pipe 600.

Figs. 2 and 3 show a radial direction and a longitudinal direction sectional view in a state where the superconducting cable shown in Fig. 1 is installed in a horizontal direction. Superconducting cables can generally be installed horizontally in the ground or underground. Therefore, the cross-sectional shape of the superconducting cable in the state where the superconducting cable is installed in the horizontal direction may be in the form as shown in FIG. 2 and FIG.

That is, when the superconducting cable 1000 is horizontally installed due to the load of the cooling part and the core part inside the vacuum chamber 500, the lower part of the vacuum chamber 500 is moved in the gravity direction, And the outer metal pipe 600 are approachable.

Of course, the outer surface of the lower part of the heat insulating part 400 and the inner surface of the outer metal pipe 600 are prevented from contacting with each other by the spacer according to the drawings of FIGS. 2 and 3, It can be physically maintained.

When the superconducting cable is installed in the horizontal direction, as shown in the enlarged view of FIG. 2 or in FIG. 3, the outer metallic pipe 600 is connected to the heat insulating part 400 via the spacer 560, May cause thermal intrusion.

In this case, if the number of the spacers is increased, it can be understood that the contact area used for the heat intrusion path is increased, and if the contact area is large, the heat penetration amount can also be increased.

Therefore, the superconducting cable according to the present invention adopts a method of minimizing the thermal invasion amount by applying a method of controlling the diameter of the spacer or the pitch of the winding, while winding one spacer.

Experimentally, when the winding pitch of the spacer 560 for preventing contact between the heat insulating portion and the outer metal pipe 600 is 200 mm to 800 mm, It has been confirmed that it is possible to prevent the heat insulating part 400 from contacting the inner surface of the outer metal pipe 600 and to separate the thermal insulating part 400 from the outer metal pipe 600.

Table 1 below shows that the pitch of the windings of the superconducting cable is doubled from 150 millimeters (mm), and the heat loss per unit length of the superconducting cable (W / m) FIG. 4 is a graph showing a heat loss amount over time in a case where the winding pitch, which is the second verification example, is 300 millimeters (mm).

Pitch (mm)

150mm
300mm
600mm
1200mm
Heat loss (W / m)

2.3
1.0
1.0

1.2

In the case where the pitch of the windings of the spacer 560 is 150 millimeters (mm) and the case where the pitch of the windings of the spacers 560 is not more than 200 millimeters (mm) and 1200 millimeters (mm) (Mm) and 600 mm (mm), which are between 800 mm (mm).

In the case where the pitch of the windings of the spacer 560 is 150 millimeters (mm) or less, the spacer is wound too tightly to prevent the contact between the heat insulating portion 400 and the outer metal pipe 600 The heat penetration path through the spacer is increased and the heat penetration amount is increased. When the winding pitch is 1200 mm (millimeter) or more, which is 800 mm or more, the heat insulating portion 400 and the outer metal pipe 600 It can be understood that the contact is generated and the amount of heat penetration is increased.

Therefore, the pitch of the windings of the spacer 560 for preventing contact between the heat insulating portion and the external metal pipe 600 outside the heat insulating portion 400 does not deviate from 200 mm (millimeters) to 800 mm (mm) desirable.

As shown in Fig. 4, even in the case of the second verification example in which the winding pitch is included in the range of 200 millimeters (mm) to 800 millimeters (mm), a certain period of time for stabilizing the superconducting power system, for example, It can be seen that the heat loss amount of the heat insulating portion 400 is stabilized at 1 W / m, and the heat insulating portion 400 and the external metal pipe 600 are not in contact with each other and at the same time, It can be interpreted that it means that the area is appropriately minimized.

In addition, the spacer provided in the superconducting cable according to the present invention is characterized in that it is larger in diameter than the spacer used in the conventional superconducting cable.

The weight per length of the superconducting cable may be from about 10 Kg / m to about 12 Kg / m, and the spacers may have a diameter ranging from about 5 millimeters (mm) to about 7 millimeters (mm) mm) to 4 millimeters (mm). This is because the diameter of the spacer can be increased to make the inner surface of the heat insulating portion and the inner surface of the outer metal pipe 600 easily separated from each other. The material and physical properties of the spacer will be described later.

Here, the inner metal pipe 300 or the outer metal pipe 600 has a corrugated bending structure in which the valleys and the valleys are repeatedly formed in a spiral shape, and the winding direction of the spacer and the inner metal pipe or the outer metal pipe 600 Or the spiral direction in which the floor structure is formed are preferably made different from each other.

When the superconducting cable is installed in the horizontal direction, the spacers located in the lower portion of the resonator may be arranged such that the winding direction of the spacers is the same as the spiral direction in which the internal metal pipe or the valley or the floor structure of the external metal pipe 600 is formed. The heat penetration path between the spacer and the outer metal pipe 600 is increased and the amount of heat penetration can be increased.

In order to prevent this, the winding direction of the spacer and the helical direction in which the inner metal tube or the outer metal tube 600 is formed must be different from each other so that the spacer is seated on the valley of the metal tube and used as a heat intrusion path .

 The material of the spacer 560 may be polyethylene (FEP, PFA, ETFE, PVC, P.E, PTFE).

The spacer 560 may be made of polytetrafluoroethylene (PTFE) or may be coated with a fluororesin or the like on the back surface of the spacer 560. In this case, the fluorinated polyethylene preferably satisfies the following conditions.

That is, fluorinated polyethylene which can be applied to the spacer 560 has a thermal conductivity of not more than 6 (10-4 cal / cm.sec. ° C) 6 according to ASTM C177 in terms of physical properties, and the mechanical properties are based on the ASTM test method a tensile strength of 175 kgf / cm ² or more, the elastic modulus is 3000kgf / cm ² or more, the compressive strength over 100 kgf / cm ^2, it is preferred that the machinability is superior fluorinated polyethylene.

The fluorinated polyethylene which satisfies the above conditions is a type of fluororesin which forms a highly stable compound due to a strong chemical bond between fluorine and carbon, and thus has almost complete chemical inertness, heat resistance, non-tackiness, excellent insulation stability, . Since the fluorinated polyethylene satisfying the above conditions has a certain degree of flexibility, it can spirally wrap the heat insulating part 400, can be disposed in the longitudinal direction of the superconducting cable, and has a certain degree of strength And serves as a separating means for preventing contact between the heat insulating part 400 and the external metal pipe 600 to physically maintain the spacing space constituting the vacuum 500. [

Sectional shape of the spacer 560 is shown as a circular shape, and various shapes such as an inner shape, a circle shape, a triangle shape, a square shape, and a star shape are possible. When the spacer is made of a material having sufficient strength, The amount of heat penetration can be reduced by narrowing the path or increasing the length of the path.

The outer metal pipe 600 may be provided outside the vacuum chamber 500 provided with the spacer 560. The outer metal pipe 600 may have the same shape and material as the inner metal pipe 300 and the outer metal pipe 600 may have a larger diameter than the inner metal pipe 300, It is possible to form a spacing space. The outer metal pipe 600 may have the same structure and material as the inner metal pipe 300 so as to have excellent bending characteristics and rigidity.

An outer jacket-shaped sheath 700 may be provided outside the outer metal pipe 600 to perform an outer function for protecting the inside of the superconducting cable. The sheath may be made of a sheath constituting a conventional sheath 700 of a power cable. The sheath portion 700 prevents corrosion of the metal pipe 600 and the like inside the sheath portion 700 and prevents damage to the cable due to external force. The sheath portion 700 may be made of a material such as polyethylene (PE) polyvinyl chloride (PVC).

FIG. 5 is a perspective view of a superconducting cable according to another embodiment of the present invention. FIG. 6 is a cross-sectional view of the superconducting cable of FIG. 5 in a horizontal direction.

The description with reference to FIGS. 1 and 2 will be omitted. 5 and 6 illustrate a three-phase superconducting cable in which the number of core units 100 provided in the superconducting cable is three.

5 and 6, unlike the embodiment shown in Figs. 1 and 2, a superconducting conductor layer is provided in each of the core portions and two shield layers are provided in Fig. 6 This is an example to which the illustrations can be applied.

The three-phase superconducting cable may have a structure in which the core units 100 share the cooling unit 200 outside the three core units 100 instead of having the cooling unit 200 independently, And the vacuum 500 may also be shared outside the cooling unit 200.

In the case of the three-phase superconducting cable according to the present invention shown in FIGS. 5 and 6, the spacers provided between the inner metal pipe 300 and the outer metal pipe 600 include a coil having a pitch of 200 mm To 800 mm and the diameter of the spacer is about 5 millimeters (mm) to 7 millimeters (mm) to reliably separate the heat insulating portion from the external metal pipe 600 and reduce the number of spacers The amount of heat penetration can be minimized by adjusting the pitch of the winding, which is the same as the above embodiment.

In the case of the three-phase superconducting cable according to the present invention shown in FIGS. 5 and 6, since there are three core portions, the cooling portion and the vacuum portion are shared, The heat invasion by the heat conduction to the inside can be minimized is the same as the embodiment shown in Figs. 1 and 2 described above.

 While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. . It is therefore to be understood that the modified embodiments are included in the technical scope of the present invention if they basically include elements of the claims of the present invention.

1000: Superconducting cable
100: core part
130: superconducting conductor layer
180: superconducting shield layer
200:
300: internal metal tube
400:
500: the jeans study
560: Spacer
600: outer metal tube
700: Shethubu

Claims (7)

A core part including a superconducting conductor layer provided outside the former, an insulating layer outside the superconducting conductor layer, and a superconducting shielding layer outside the insulating layer;
An inner metal tube provided on the outer side of the core portion and having a circulation flow path of liquid coolant for cooling the core portion inside;
A heat insulating part provided on the outer side of the inner metal tube and formed by winding a heat insulating material a plurality of times;
An outer metal pipe 600 spaced apart from the heat insulating portion and maintained in a vacuum state;
A spacer wound on the outer side of the heat insulating portion so as to have a winding pitch of 200 millimeters (mm) to 800 millimeters (mm) in order to prevent contact between the heat insulating portion and the outer metal tube; And
And an outer jacket surrounding the outer metal tube. The method according to claim 1,
Wherein the superconducting cable has a weight per unit length of 10 Kg / m to 12 Kg / m. The method according to claim 1,
Wherein one spacer is provided and the diameter of the spacer is 5 millimeters (mm) to 7 millimeters (mm). The method according to claim 1,
Wherein the spacer is made of fluorinated polyethylenes. 5. The method of claim 4,
The fluorinated polyethylene has a thermal conductivity of 6 or less (10-4 cal / cm.sec. ° C) in accordance with ASTM C177 as a physical property, a tensile strength of 175 kgf / cm ² or more as a mechanical property, elastic modulus of the superconducting cable, characterized in that not less than 3000kgf / cm ² or higher, the compression strength of 100 kgf / cm ^2. The method according to claim 1,
The inner metal tube or the outer metal tube has a corrugated bent structure in which the valley and the floor are repeatedly formed and the winding direction of the spacer is different from the spiral direction in which the valley or the floor structure of the inner metal tube or the outer metal tube is formed Features superconducting cable. A core part including a former, a superconducting conductor layer and a superconducting shielding layer;
A cooling unit disposed on the outer side of the core unit and including a circulating flow path for liquid coolant for cooling the core unit;
A heat insulating portion provided outside the cooling portion to block heat intrusion by radiation;
A spacer which spirally surrounds the outer side of the heat insulating portion and has a diameter of 5 millimeters (mm) to 7 millimeters (mm) and is made of a fluorinated polyethylene material;
An outer metal pipe provided outside the heat insulating portion to prevent contact with the heat insulating portion by the spacer; And
And an outer jacket surrounding the outer metal tube.

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