KR102573476B1 - Connecting Structure For Superconductive Cable - Google Patents

Abstract

The present invention relates to an intermediate connection structure for intermediate connection of superconducting cables. More specifically, the present invention relates to an intermediate connection structure capable of preventing damage to a superconducting cable and an intermediate connection structure by suppressing shrinkage generated in a superconducting cable and an intermediate connection structure when a liquid refrigerant is supplied to a superconducting power system. it is about

Description

Intermediate connection structure for intermediate connection of superconductive cable {Connecting Structure For Superconductive Cable}

The present invention relates to an intermediate connection structure capable of preventing damage to a superconducting cable and an intermediate connection structure by suppressing shrinkage generated in a superconducting cable and an intermediate connection structure when a liquid refrigerant is supplied to a superconducting power system.

The present invention relates to an intermediate connection structure for intermediate connection of superconducting cables. A superconducting cable may include a superconducting layer and a superconducting shielding layer, respectively, and the superconducting layer and the superconducting shielding layer may be composed of superconducting wires. Superconducting wires have high power transmission capability even at low voltages because their electrical resistance converges to zero at a constant temperature.

A superconducting wire can have an intended power transmission capability only when a constant temperature, that is, a cryogenic environment is maintained.

Recently, long-length laying of superconducting cables has been tested. In order to install the superconducting cable in the long run, the superconducting cable must be connected in the middle at predetermined distances.

In order to maintain the cryogenic environment of the superconducting cable, a cooling unit for cooling the superconducting wire by flowing a cooling fluid and a vacuum unit for vacuum insulation around the cooling unit are provided inside the superconducting cable, and the cooling unit and vacuum unit are provided inside the intermediate connection structure. should also be maintained.

Therefore, the inside of the intermediate connection structure is composed of a multi-layered structure with a space in which the liquid refrigerant is accommodated and flows and a space in which a vacuum region for vacuum insulation is formed.

A connection part to which both cores of the superconducting cable are connected is provided in a space where the liquid refrigerant is accommodated inside the intermediate connection structure. The connection part to which both cores are connected includes a former inside the superconducting cable, a superconducting wire constituting the superconducting layer disposed around the former, an insulating layer surrounding the superconducting layer, and a superconducting wire constituting the superconducting shielding layer disposed around the insulating layer. etc. are interconnected, and the connecting portion has a length and an enlarged diameter required for the connection.

In addition, when a liquid refrigerant is supplied to the cooling part of the superconducting cable, contraction occurs, and an inner metal tube partitioning the former and the cooling part and an outer metal tube partitioning the vacuum part may be considered.

The former is disposed in the center of the core part, and an insulating layer is provided between the superconducting layer and the superconducting shielding layer. The insulating layer may use insulating paper made of kraft paper or PPLP material, and may be configured by winding the insulating paper a plurality of times.

Therefore, when the liquid refrigerant is supplied between the core of the superconducting cable and the inner metal tube, the former, which are components of the core, and the inner metal tube and the outer metal tube, have large variations in cooling rates. In particular, the faster the injection speed of the liquid refrigerant, the larger the deviation. That is, unlike the inner metal tube in direct contact with the liquid refrigerant, the former cools slowly because the cooling can be buffered by the insulating layer, and the inner metal tube is cooled most quickly because it comes in direct contact with the liquid refrigerant, and the outer metal tube is the inner metal tube. It is spaced between the metal tube, the insulation layer, and the vacuum part, and it is hardly cooled because it is greatly affected by the external room temperature. It can be understood that this causes a difference in cooling rates between the former and the inner and outer metal tubes.

In this case, in the intermediate connection structure, mechanical interference may occur, such as collision between the inner housing connected to the inner metal tube of the superconducting cable, which is rapidly cooled and rapidly contracted, and the connection part of the core part, which is cooled relatively slowly and contracts slowly. .

When interference occurs between the connection part of the core and the internal structure of the intermediate connection structure, a fatal problem such as damage to superconducting wires such as a superconducting shielding layer connected at the outermost part of the connection part may occur. In particular, as the length of installation increases, the deviation of the contraction distance increases, making this problem more serious.

Therefore, when a liquid refrigerant is initially supplied in a superconducting power system, a solution to a problem caused by cooling contraction occurring in a superconducting cable or an intermediate connection structure is required.

The present invention solves the problem of providing an intermediate connection structure capable of preventing damage to a superconducting cable and an intermediate connection structure by suppressing shrinkage generated in a superconducting cable and an intermediate connection structure when a liquid refrigerant is supplied to a superconducting power system. do what you want to do.

In order to solve the above problems, the present invention provides a core portion sequentially provided with a former, a superconducting conductor layer, an insulating layer and a superconducting shielding layer; an inner metal tube accommodating a cooling unit cooling the core unit with a liquid refrigerant passing through a cooling passage outside the core unit; and an outer metal tube defining a vacuum part surrounding the outer side of the inner metal tube. In the intermediate connection structure for intermediate connection between superconducting cables, both cores of the superconducting cable are internally connected, and the inner metal tube of the superconducting cable An inner housing connected to accommodate the liquid refrigerant, an outer housing for vacuum insulating the outside of the inner housing, and a shrinkage prevention member having one end fixed to the outer metal tube of the superconducting cable and the other end fixed to the outer housing It is possible to provide an intermediate connection structure of a superconducting cable, characterized in that.

In addition, when the inner housing and the outer housing are supplied with liquid refrigerant through the inner metal pipe of any one superconducting cable, the inner housing connected to the inner metal pipe of the superconducting cable contracts in the direction opposite to the supply direction of the liquid refrigerant. A fixing member connecting and fixing an outer surface of the inner housing and an inner surface of the outer housing may be further included so as to be shared with the outer housing.

Here, the shrinkage preventing member supports a contraction force for shrinking of the inner metal tube of the superconducting cable, the inner housing connected to the inner metal tube, and the outer housing connected to the inner housing by the fixing member in a direction opposite to the supply direction of the liquid refrigerant. can do.

And, the cross-section of the shrinkage prevention member ?a? It may be configured in a ring shape which is a ruler shape.

A vacuum area inside the outer housing surrounding the inner housing of the intermediate connection structure may be divided into two parts.

In addition, the outer metal tube of the superconducting cable is connected to the inner housing of the intermediate connection structure by an inner corrugated tube to form a first vacuum region communicating with the vacuum part inside the outer metal tube of the superconducting cable, and the intermediate connection structure It is connected to the outer housing and the outer corrugated pipe to form a second vacuum region therein.

The first vacuum region may surround both end regions of the inner housing of the intermediate connection structure and communicate with the vacuum portion of the superconducting cable, and the second vacuum region may cover a circumferential surface of the inner housing of the intermediate connection structure.

In addition, the outer metal tube of the superconducting cable may be connected to the inner corrugated tube and the outer corrugated tube by a connecting member.

Also, the tensile strength of the anti-shrinkage member may be greater than that of the outer metal tube of the superconducting cable.

Here, the height of the anti-contraction member in a vertical direction may be greater than the width in a horizontal direction.

In addition, in order to solve the above problems, a core part including a superconducting conductor layer, an inner metal tube accommodating a cooling part for cooling the core part with a liquid refrigerant through a cooling passage outside the core part, and a vacuum part surrounding the outside of the inner metal tube In an intermediate connection structure for intermediate connection between superconducting cables including an outer metal tube dividing the outer metal tube, one end is attached to the outer metal tube of the superconducting cable in order to prevent damage to the connection structure due to a difference in shrinkage between the inner metal tube and the outer metal tube. It is fixed, and the other end may include a shrinkage prevention member fixed to an outer housing for constituting an outer shape of the intermediate connection structure and vacuum insulating the inside thereof.

In this case, both cores of the superconducting cable are internally connected, and further include an inner housing connected to the inner metal tube of the superconducting cable to accommodate the liquid refrigerant, and the inner housing connected to the inner metal tube of the superconducting cable to supply the liquid refrigerant. A fixing member connecting and fixing an outer surface of the inner housing and an inner surface of the outer housing may be further included so that the contraction force contracted in the opposite direction is shared with the outer housing.

According to the intermediate connection structure of the superconducting cable according to the present invention, when the liquid refrigerant is supplied to the superconducting power system, the superconducting cable and the intermediate connection structure are prevented from shrinking, thereby preventing damage to the superconducting cable and the intermediate connection structure. It is possible to provide an intermediate connection structure that can prevent the

The intermediate connection structure of the superconducting cable according to the present invention prevents damage to parts, etc. that may occur when shrinkage occurs due to the supply of refrigerant through a shrinkage prevention member even when the cable and the junction box are connected with a corrugated pipe to offset errors in construction. It can be prevented, so the effect of improving the stability of the system can be obtained.

1 shows a simplified configuration diagram of a superconducting power system including an intermediate connection structure of a superconducting cable according to the present invention.
FIG. 2 shows a perspective view of a superconducting cable to which a superconducting wire according to the present invention is applied step by step.
FIG. 3 shows a cross-sectional view of the superconducting cable shown in FIG. 2;
4 shows a cross-sectional view of an intermediate connection structure according to the present invention.
5 is a view of the core of the superconducting cable, the inner metal tube, and the inner housing constituting the intermediate connection structure by the contraction preventing member when liquid refrigerant is supplied through one superconducting cable of the superconducting cables connected to the intermediate connection structure shown in FIG. It shows a state in which contraction is blocked.

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 and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete, and the spirit of the present invention will be sufficiently conveyed to those skilled in the art. Like reference numbers indicate like elements throughout the specification.

1 shows a simplified configuration diagram of a superconducting power system including an intermediate connection structure 2000 of a superconducting cable according to the present invention.

The superconducting power system includes a superconducting cable 1000 having a predetermined length, a termination box 3000 to which each end of the superconducting cable is connected to supply power to a room temperature region, and the length of the entire section of the power system. According to this, it may be configured to include an intermediate connection structure 2000 for intermediately connecting the superconducting cables.

Since the superconducting power system maintains a cryogenic environment by supplying liquid refrigerant through the cooling passage of the superconducting cable, a refrigerant cooling device (not shown) is provided separately from the cooling passage circulating the superconducting cable, the intermediate connection structure (2000), and the termination box. ), etc. may be provided.

Before power is supplied through the superconducting power system, the superconducting cable must first form a cryogenic environment. In this case, liquid refrigerant starts to be supplied to the cooling part of a specific superconducting cable among the superconducting cables connected in the intermediate connection structure 2000.

The superconducting cable may have a configuration in which the internal former, the internal metal tube, and the external metal tube greatly shrink during cooling, but as can be seen through the configuration of the superconducting cable described with reference to FIGS. 2 and 3, the liquid refrigerant In the cooling process, a difference in cooling rate or shrinkage rate may occur.

Referring to FIG. 2, the structure of the superconducting cable will be described.

FIG. 2 shows a perspective view of a superconducting cable to which a superconducting wire according to the present invention is applied step by step.

The superconducting cable shown in FIG. 2 includes a former 110 and at least two or more superconducting conductor layers 130 including a plurality of superconducting wires disposed side by side in the longitudinal direction of the former 110 so as to surround the outside of the former 110. ), an insulating tape 140 surrounding the superconducting conductor layer 130, and a plurality of superconducting wires arranged side by side in the longitudinal direction of the former 110 so as to wrap the outside of the insulating tape 140. At least two A core portion 100 including a superconducting shielding layer 180 of one or more layers, provided outside the core portion 100 to cool the core portion 100, and a liquid phase for cooling the core portion 100 A cooling unit 200 having a refrigerant flow path for a refrigerant, an inner metal tube 300 provided outside the cooling unit 200, and a heat insulating material 401 provided outside the inner metal tube 300, wound in several layers. A heat insulating part 400 forming a heat insulating layer, a vacuum part 500 having a plurality of spacers 560 at spaced positions outside the heat insulating part 400 in order to vacuum insulate the cooling part 200, An external metal pipe 600 provided outside the vacuum unit 500 and an external jacket 700 provided outside the external metal pipe 600 to form a sheath layer may be included.

Each component constituting the superconducting cable is sequentially reviewed as follows. The former 110 serves as a frame for forming a shape as well as providing a place to mount a flat, flat and long superconducting wire around the former 110, and can be a path through which fault 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 into a circular shape.

Specifically, the former 110 basically has a round cylindrical shape, and serves as a frame for placing a flat and long superconducting wire. The diameter of the former 110 is determined in consideration of the width of the superconducting wire so that the superconducting wire does not lift and when the superconducting wire is placed on the former 110, the structure is as close to a circular shape as possible.

As shown in FIGS. 2 and 3, the former may be configured in a form with a full center, but the former 110 is formed in a hollow pipe shape and serves as a frame for raising the superconducting wire and at the same time contains a refrigerant therein. It can be configured to serve as a path for movement, and each of the conductor wires 111 constituting the former can be made of copper, etc., and 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 a fault current due to a short circuit in the system (??, lightning, insulation breakdown, etc.).

However, in the present invention, an example in which the former is composed of a solid type will be mainly described.

When a fault current occurs in the power system, the role of the return conductor is a conductive layer made of metal that is attached to each superconducting wire and has conductivity at room temperature, as will be described later, in addition to the former composed of the conductor wire 111. The conducting layer may be in the form of a metal tape. A detailed description of this will be given later.

Depending on the capacity of the fault current, the cross-sectional area of a conductor such as copper constituting the wire may be determined, and in the case of high voltage, the copper wire may be compressed into a circular shape to form a twisted wire.

The surface of the former 110 is inevitably convex because it forms a twisted pair by compressing several strands of circular cross-sectional circular conductor wires 111 constituting the former 110 into a circular shape. Accordingly, the smoothing layer 120 may be coated on the outside of the former 110 to smooth the convex surface of the former 110 . For the smoothing layer 120, a material such as semiconductive carbon paper or brass tape may be used.

Although not shown in the drawings, a 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 using a semiconducting carbon paper tape.

A first superconducting conductor layer 130a formed as a layer surrounded by a plurality of superconducting wires 131 may be provided outside the former 110 flattened by the smoothing layer 120 . 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 shown in FIG. 2 , the superconducting conductor layer 130 may be configured in multiple layers according to the capacity of current to be transmitted or distributed through the superconducting cable.

The embodiment shown in FIG. 2 shows that a total of two superconducting conductor layers 130a and 130b are provided. In addition, if 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 this problem, when a multi-layered superconducting conductor layer is provided, an insulating tape 140 may be provided between the superconducting conductor layers 130a and 130b. The insulating tape 140 is disposed between the stacked superconducting conductor layers 130a and 130b to insulate the superconducting conductor layers 130a and 130b from each other, thereby preventing the skin effect of the stacked superconducting wires. Conducting directions of the multi-layered superconducting conductor layers may be matched by the insulating tape 140 .

In the embodiment shown in FIG. 2, the superconducting conductor layer 130 is an example composed of two layers, a first superconducting conductor layer 130a and a second superconducting conductor layer 130b. A conductor layer may be provided.

In addition, each superconducting wire constituting each of the superconducting conductor layers 130a and 130b may be connected in parallel to each element constituting the former 110 . This is to ensure that the current flowing through the superconducting wire is divided into the wires of the former 110 in case of an accident such as a short circuit (??, lightning, insulation breakdown, destruction of superconducting conditions, etc.). In this way, heat generation or damage of the superconducting wire can be prevented.

An internal semiconducting layer 150 may be provided on the 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 alleviate electric field concentration in each region of the superconducting conductor layer 130 and to make the surface electric field uniform. Specifically, it may be provided to alleviate the concentration of the electric field generated at the corner of the superconducting wire and to make the electric field distribution even. This is also true of the outer semiconducting layer 170 to be described later.

The internal 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 dielectric strength of the superconducting cable. In general, XLPE (Cross Linking-Polyethylene) or oil-filled cables are used to insulate high-voltage cables, but superconducting cables are cooled to cryogenic temperatures for superconductivity of superconducting wires, and XLPE is damaged at cryogenic temperatures to cause insulation breakdown. There are problems, and since an oil-filled cable may cause environmental problems, etc., the superconducting cable of the present invention can use insulating paper made of ordinary paper as the insulating layer 160, and the insulating layer 160 It may be configured in a manner of winding the insulating paper a plurality of times.

Kraft paper or PPLP (Polypropylene Laminated Paper) is mainly used for the insulating paper. Among various low-insulation materials, in the case of superconducting cables, PPLP insulation paper is used in consideration of ease of winding and dielectric strength characteristics.

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

The former 110 located inside the core of the superconducting cable may have an effect of buffering the cooling rate when liquid refrigerant is supplied to the cooling unit by the thick insulating layer 160 or the like. This is because, as will be described later, the connection part 2100 of both superconducting cables connected through the intermediate connection structure 2000 may cause a physical collision with the inner housing 2200 connected to the inner metal tube of the superconducting cable. need. A description of this will be given later.

Also, a superconducting shielding layer 180 may be provided outside the outer semiconducting layer 170 . A method of forming the superconducting shielding layer 180 may be the same as the method of forming the superconducting conductor layer 130 . If the surface of the outer semiconducting layer 170 is uneven, a smoothing layer (not shown) may be provided if necessary, and superconducting wires for forming the superconducting shielding layer 180 are placed outside the smoothing layer in a circumferential direction, respectively. can be placed side by side.

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

A core exterior layer 190 serving as an exterior for the core unit 100 may be provided outside the superconducting shielding layer 180 . The core exterior layer 190 may include various types of tapes or binders, and serves to bind all components of the core unit 100 and an exterior role so that the core unit 100 can be exposed to a cooling layer to be described later. It performs, and may be composed of a metal tape such as SUS material.

In this way, the core part 100 of the superconducting cable can be constructed. In FIGS. 2 and 3, the smoothing layer and the semiconducting layer are shown as being composed of a single layer of the same material, but various auxiliary layers as needed. may be added.

A 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 a liquid refrigerant circulation path may be provided inside the cooling unit 200. Liquid nitrogen may be used as the liquid refrigerant, and the liquid refrigerant (liquid nitrogen) circulates through the refrigerant passage in a cooled state to have a temperature of -200 degrees below zero and is provided in the core part 100 inside the cooling part. It is possible to maintain a cryogenic temperature, which is a superconducting condition of a superconducting wire material.

The cooling passage provided in the cooling unit 200 can allow the liquid refrigerant to flow in one direction, and is recovered from the termination box of the superconducting cable or the intermediate connection structure 2000 and re-cooled to cool the cooling unit 200 again. It can be supplied to the cooling passage.

An inner metal tube 300 may be provided outside the cooling unit 200 . The inner metal tube 300 together with the outer metal tube 600 to be described later serves as an exterior for the superconducting cable to prevent mechanical damage to the core part 100 during installation and operation of the superconducting cable. The superconducting cable is wound around a drum for easy manufacturing and transportation, and during installation, since the cable wound around the drum is unfolded and installed, bending stress or tensile stress may be continuously applied to the superconducting cable.

An internal metal tube 300 may be provided in order to maintain initial performance even when such mechanical stress is applied. Therefore, the inner metal pipe 300 has a corrugation bending structure in which elevation and depression are repeated in the longitudinal direction of the superconducting cable in order to reinforce rigidity against mechanical stress. The inner metal pipe 300 is made of a material such as aluminum may consist of

Since the inner metal tube 300 is provided outside the cooling unit 200, it may be at a cryogenic temperature corresponding to the temperature of the liquid refrigerant. Accordingly, the inner metal tube 300 may be classified as a low-temperature metal tube.

Therefore, when the liquid refrigerant starts to be supplied through the inner metal tube 300 that partitions the cooling unit 200, the inner metal tube 300 becomes the former 110 of the core unit 100 described above or the outer metal tube 600 described later. ) is cooled more quickly, and shrinkage caused by cooling may occur.

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 in which a heat insulating material thinly coated with a high reflectance metal film and a polymer having low thermal conductivity is wound in several layers. The heat insulation layer constitutes multi-layer insulation (MLI) and may be provided to block heat intrusion into the inner metal pipe 300.

In particular, since the inner metal pipe 300 is made of a metal material, heat penetration or heat exchange by conduction is easy, so that the heat insulator 400 can minimize heat exchange or heat penetration mainly by conduction, and metal having high reflectivity. Due to the film material, an effect of preventing heat exchange or heat invasion by radiation can also be obtained.

The number of layers of the insulator 400 can be adjusted to minimize heat intrusion. If it is composed of many layers, the radiant heat blocking effect is increased, but it is important to use an appropriate number of layers because the conductive heat blocking effect and the heat blocking effect by convection due to the thinning of the vacuum layer are reduced.

A vacuum unit 500 may be provided outside the insulation unit 400 . The vacuum unit 500 may be provided to minimize heat transfer by convection or the like toward the insulation layer, which may occur when the insulation by the insulation unit 400 is insufficient.

The vacuum unit 500 may be formed by forming a separation space outside the heat insulation unit 400 and vacuuming the separation space.

The vacuum unit 500 is a separation space provided to prevent heat intrusion due to convection or the like from the outside at room temperature toward the core unit, and may include at least one spacer 560 to form a physical separation space. The separation space in the entire area of the superconducting cable to prevent contact between the outer metal tube 600 provided outside the separation space in the vacuum unit 500 and the insulation part 400 inside the vacuum unit 500. At least two spacers 560 may be provided inside, and may be increased or decreased according to the type or size of the superconducting cable or spacer. Although the superconducting cable 1000 shown in FIGS. 2 and 3 is illustrated as having four spacers, the number may be increased or decreased.

The spacer 560 may be disposed along the longitudinal direction of the superconducting cable, and may be wound around the outside of the core part 100, specifically, the insulation part 400 in a spiral or circular shape.

The number of spacers 560 may be 3 to 5 spacers in the superconducting cable of the present invention. The spacer may form a separation space to prevent heat exchange by conduction, and the structure of the spacer may be composed of a single layer or a multi-layer structure.

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

In addition, the spacer 560 may be made of fluorinated polyethylene (PTFE, Poly Tetra Fluoro Ethylene) material, or made of a general resin or polyethylene material and then coated with fluorinated polyethylene material. In this case, the fluorinated polyethylene may be Teflon.

Teflon is a type of fluorine resin. Teflon forms a very stable compound due to the strong chemical bond between fluorine and carbon, and has properties such as almost perfect chemical inertness, heat resistance, non-adhesiveness, excellent insulation stability, and low friction coefficient. there is. In addition, since Teflon has a certain degree of flexibility, it wraps around the insulator 400 in a spiral shape, can be wound and disposed in the longitudinal direction of the superconducting cable, and has a certain degree of strength, so that the insulator 400 and the outside It can be used as a separation means to prevent contact of the metal tube 600 and 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-section of the spacer 560 may have various shapes such as a circular shape, a triangular shape, a square shape, and a star shape.

An external metal tube 600 may be provided outside the vacuum unit 500 provided with the spacer 560 . The outer metal tube 600 may be made of the same shape and material as the inner metal tube 300, and the outer metal tube 600 has a larger diameter than the inner metal tube 300, so that the spacer 560 It is possible to form a separation space. A detailed description of the spacer 560 is deferred.

Therefore, when the liquid refrigerant starts to be supplied through the inner metal pipe 300 that partitions the cooling unit 200, the outer metal pipe 600, unlike the inner metal pipe 300, uses an insulation part or a vacuum part to form the inner metal pipe ( 300), the cooling rate or shrinkage rate becomes slower. The superconducting cable of the present invention includes an inner metal tube 300 as a low-temperature metal tube and an outer metal tube 600 as a normal-temperature metal tube, which are respectively an inner housing 2200 and an outer housing 2300 of an intermediate connection structure 2000 and Connected.

Therefore, the difference in shrinkage due to the cooling rate deviation of the inner metal pipe 300 and the outer metal pipe 600 according to the supply of refrigerant may cause problems such as damage to the connection portion with the intermediate connection structure 2000, so that such a problem can be solved. There is a need.

Also, an outer jacket 700 performing an exterior function for protecting the inside of the superconducting cable may be provided outside the outer metal tube 600 . As the outer jacket, a sheath material constituting the outer jacket 700 of a conventional power cable may be used. The external jacket 700 can prevent corrosion of the metal pipe 600 therein and the like, and can prevent damage to the cable due to external force. It may be made of materials such as polyethylene (PE) and polyvinyl chloride (PVC).

4 shows a cross-sectional view of an interconnection structure 2000 according to the present invention.

In the present invention, the former 110, the superconducting conductor layer 130, the insulating layer 160, and the superconducting shielding layer 180 are sequentially provided in the core part 100, and through a cooling passage outside the core part 100. A superconducting cable including an inner metal tube 300 accommodating the cooling unit 200 for cooling the core unit with a liquid refrigerant, and an outer metal tube 600 partitioning the vacuum unit 500 surrounding the outer side of the inner metal tube 300. In the intermediate connection structure for intermediate connection between the superconducting cable 1000, both core parts 100 of the superconducting cable 1000 are internally connected, and the inner housing 2200 is connected to the inner metal tube of the superconducting cable to accommodate a liquid refrigerant; An outer housing 2300 for vacuum insulating the outside of the inner housing and a shrinkage prevention member 2600 having one end fixed to the outer metal tube 300 of the superconducting cable and the other end fixed to the outer housing 2300 It is possible to provide an intermediate connection structure 2000 of a superconducting cable that

The intermediate connection structure 2000 of superconducting cables according to the present invention connects the superconducting cables 1000 at predetermined intervals to construct a long-distance superconducting power system.

A connection part 2100 is provided inside the intermediate connection structure 2000 to interconnect the core parts 100 of the two superconducting cables connected in a cryogenic environment.

In the connection part 2100, the former, the superconducting layer, and the superconducting shielding layer of both superconducting cables are connected, respectively, and the cooling part inside the superconducting cable is moved around the connection part 2100 to maintain a cryogenic environment in the area around the connection part 2100. It is configured to extend and expand.

The intermediate connection structure 2000 includes an inner housing 2200 so that the cooling unit 200 inside the superconducting cable 1000 extends and expands around the connection unit 2100 .

The inner housing 2200 accommodates the connection part 2100 to which the core of the superconducting cable is connected, and is connected to the inner metal tube 3000 of the superconducting cable so that the cooling part of the superconducting cable extends and expands.

The inner housing 2200 and the outer housing 2300 constituting the intermediate connection structure 2000 may be made of stainless steel, and the inner metal tube 300 and the outer metal tube 600 of the superconducting cable 1000 are made of aluminum. Alternatively, it may be made of stainless material, and when aluminum is applied, since both metals are materials that are difficult to weld, the joint between each metal tube and the housing can be joined through dissimilar metal joints 1500a and 1500b for dissimilar metal bonding. there is. The dissimilar metal junctions 1500a and 1500b are junction means composed of dissimilar metals, which are joined in a structure in which dissimilar metals are divided in advance.

The connection part 2100 of the core is disposed in the accommodation space within the inner housing 2200 of the intermediate connection structure 2000 connected to the inner metal tube 300 of the superconducting cable. The inside of the inner housing 2200 is a space in which liquid refrigerant flows, and a cryogenic environment must be maintained.

Therefore, the intermediate connection structure 2000 according to the present invention also maintains a cryogenic environment with a dual structure such as the cooling unit 200 and the vacuum unit 500 of the superconducting cable.

Therefore, the intermediate connection structure 2000 according to the present invention includes an outer housing 2300 for vacuum insulating the outside of the inner housing 2200 . The outer housing 2300 may be connected to the outer metal tube of the superconducting cable.

And, as will be described later, since the vacuum region inside the intermediate connection structure 2000 is composed of a first vacuum region v1 and a second vacuum region v2, the outer metal tube 600 of the superconducting cable In addition to the outer metal tube of the superconducting cable 1000, the inner metal tube 300 of the superconducting cable may also be connected through corrugated tubes.

The inside of the outer housing 2300 is maintained in a vacuum state so that the circumference of the inner housing 2200 may be vacuum insulated.

The intermediate connection structure 2000 according to the present invention is characterized in that the vacuum area for vacuum insulation of the inner housing 2200 is divided into two parts.

For convenience of description, the first vacuum region v1 is defined as a vacuum region that communicates with the vacuum portion 500 formed inside the outer metal tube of the superconducting cable 1000 and vacuum-insulates the end region of the inner housing 2200, and the cylindrical inner metal tube. (2200) The vacuum area surrounding the circumference is divided into a second vacuum area v2.

Specifically, the outer metal pipe of the superconducting cable is connected to the inner housing 2200 of the intermediate connection structure 2000 and the inner corrugated pipe 2400, and the first vacuum communicates with the vacuum part inside the outer metal pipe of the superconducting cable. An area v1 is formed, and the outer housing 2300 of the intermediate connection structure 2000 is connected to the outer corrugated pipe 2500 to form a second vacuum area v2 therein. The second vacuum region (v2) means a region that extends to the entire outer circumferential surface of the inner metal tube.

The reason why the vacuum area for protecting the cryogenic environment of the inner housing 2200 of the intermediate connection structure 2000 is dualized is to prevent the vacuum of the entire system from breaking together even when one vacuum state is destroyed.

A superconducting power system must continuously maintain a superconducting environment at a very low temperature, and this superconducting environment or superconducting condition is premised on cooling by liquid refrigerant and vacuum insulation by vacuum.

Therefore, it is not efficient to break the vacuum of the entire system when repairing the intermediate connection structure 2000 when it is out of order or maintaining or repairing it for other reasons. For example, superconducting cables constituting a superconducting power system may be connected in units of hundreds of meters, and vacuuming the inside may take several days.

Therefore, the vacuum region of the intermediate connection structure 2000 of the superconducting cable according to the present invention is connected to the vacuum portion of the superconducting cable and surrounds the end region of the inner housing 2200, and the first vacuum region v1 and the inner housing 2200 Even if the vacuum state of the second vacuum region (v2) is released to maintain or repair the superconducting cable in the event of a failure of the intermediate connection structure (2000), The vacuum state of the first vacuum region v1 connected to may be maintained.

Therefore, the outer metal tube of the superconducting cable is connected to the inner housing 2200 of the intermediate connection structure 2000 and the inner corrugated tube 2400, and is connected by the outer housing 2300 and the outer corrugated tube 2500 of the intermediate connection structure 2000. It can be configured to be connected.

Here, the reason why the superconducting cable and the inner housing 2200 or the outer housing 2300 constituting the intermediate connection structure 2000 are connected by a corrugated pipe is as follows.

The superconducting cable is manufactured, wound, and supplied in a predetermined unit such as a bobbin before being installed on a site after being manufactured, and is connected to an intermediate connection structure (2000) or the like at the installation site.

In this case, a certain amount of cable length error may occur during the connection process of the superconducting cable, and this error is offset by the corrugated pipe (flexible bellows) structure so that the inner metal pipe 300 and the outer metal pipe 600 of the superconducting cable are formed. By interconnecting them, the cooling unit and the vacuum unit inside the superconducting cable can be expanded and extended up to the intermediate connection structure 2000 while maintaining airtightness.

This corrugated tube structure is different from a corrugated structure of an inner metal tube or an outer metal tube constituting a superconducting cable. That is, the corrugated structure (repetition of valleys and crests) formed on the inner or outer metal tube of the superconducting cable is to improve the bending characteristics and reinforce the rigidity of the superconducting cable, but the corrugated pipe structure of the intermediate connection structure (2000) is superconducting Since it is configured to provide elasticity of the cable in the longitudinal direction, there is a difference in the thickness of the material and the wrinkle structure.

As described above, the outer metal tube of the superconducting cable is connected to the inner housing 2200 and the outer housing 2300 of the intermediate connection structure 2000 and the inner corrugated tube 2400 to divide the vacuum area into two parts. ) and an external corrugated pipe (2500).

Since the outer metal pipe of the superconducting cable has a structure in which valleys and crests are repeated, it is not easy to mount the inner corrugated pipe 2400 and the outer corrugated pipe 2500 independently, so the inner corrugated pipe of the intermediate connection structure 2000 according to the present invention 2400 and the outer corrugated pipe 2500 may be connected to the outer metal pipe 600 of the superconducting cable 1000 via a connecting member.

As shown in FIG. 4, the superconducting cable and the intermediate connection structure 2000 are connected through an inner corrugated pipe 2400 and an outer corrugated pipe 2500 in order to offset errors such as cable length generated during the cable laying process. .

However, as will be described later with reference to FIG. 5 , as soon as the supply of the liquid refrigerant starts, the inner metal pipe 300 constituting the cable and the inner housing 2200 connected thereto are rapidly cooled and contraction force is generated. Therefore, when contraction force is applied in a specific direction from the inside of the dual structure intermediate connection structure 2000 composed of the inner housing 2200 and the outer housing 2300, in order to prevent the contraction force from being applied only to the inner housing 2200 When the liquid refrigerant is supplied to the inner housing 2200 and the outer housing 2300, the inner metal pipe 300 of the superconducting cable and the inner housing 2200 of the intermediate connection structure 2000 are opposite to the supply direction of the liquid refrigerant. A fixing member 2250 connecting and fixing the outer surface of the inner housing 2200 and the inner surface of the outer housing 2300 may be further included so that the contraction force contracted in the direction is shared with the outer housing 2300.

The fixing member 2250 is configured such that, when contraction force is applied to the inner metal pipe 300 of the superconducting cable and the inner housing 2200 of the intermediate connection structure 2000, the contraction force is shared with the outer housing 2300. It can be seen that it is provided for this.

If a contraction force is applied to only one side of the inner housing 2200, collision or interference between the inner housing 2200 and the outer housing 2300 may occur, and thus it is necessary to prevent this.

Therefore, the fixing member 2250 connecting and fixing the inner housing 2200 and the outer housing 2300 of the intermediate connection structure 2000 of the superconducting cable according to the present invention is connected to the inner metal tube 300 and the intermediate connection structure of the superconducting cable. When the housing 2000 is contracted and contraction force is generated, the outer housing 2300 of the intermediate connection structure 2000 also shares the force so that physical interference between parts that may occur inside the intermediate connection structure can be prevented.

As such, when the supply of the refrigerant starts, when the contraction force is sequentially shared by the inner metal tube 300 of the superconducting cable, the inner housing 2200 and the outer housing 2300 of the intermediate connection structure 2000, FIG. The shown intermediate connection structure will change its position in a direction opposite to the supply direction of the refrigerant according to contraction of the inner metal tube 300 of the superconducting cable and the inner housing 2200 of the intermediate connection structure 2000.

In addition, the outer housing of the intermediate connection structure 2000 connected by the fixing member 2250 will also be connected via the fixing member 2250 and displaced together.

This is because the housings of the intermediate connection structure and the metal tubes of the superconducting cable are connected by respective corrugated tubes, so contraction due to contraction force cannot be prevented.

In this case, as described above, the former included in the core of the superconducting cable is relatively delayed in cooling, so that it shrinks with a smaller amount of shrinkage than the amount of shrinkage of the inner metal tube of the superconducting cable.

Therefore, in FIG. 4, the metal tube and the housing are greatly contracted in the leftward direction (opposite to the supply direction of the refrigerant), but the core and the connection part will have an effect of staying in place due to a relatively small amount of contraction. Internal components including the corner 2200e of the housing may cause a problem such as collision with the end edge 2100s of the connector 2100 having an expanded diameter.

In order to prevent this, the intermediate connection structure 2000 according to the present invention does not shrink even when a contraction force is applied to the inner metal tube 300 of the superconducting cable, the inner housing 2200 and the outer housing 2300 of the intermediate connection structure 2000. A shrinkage preventing member 2600 may be further included. This description is made with reference to FIG. 5 .

FIG. 5 is a superconducting cable connected to the intermediate connection structure 2000 shown in FIG. 4, when liquid refrigerant is supplied through one superconducting cable, the core of the superconducting cable, the inner metal tube and the intermediate connection structure by the shrinkage prevention member 2600. It shows a state in which contraction of the inner housing 2200 constituting 2000 is blocked.

5 illustrates a process in which liquid refrigerant is supplied from a specific termination box to the superconducting cable and the intermediate connection structure 2000 after the installation of the superconducting power system. In order to operate the superconducting power system, a cryogenic environment must be provided to the core of the superconducting cable including the superconductor.

Therefore, when liquid refrigerant is supplied to the cooling part of the superconducting cable through a termination box or the like, the liquid refrigerant rapidly passes through the inner metal pipe 300 of the superconducting cable and the inner housing 2200 of the intermediate connection structure 2000 in which the liquid refrigerant is accommodated. By this cooling, the inner metal tube 300 of the superconducting cable and the housings of the intermediate connection structure 2000 will shrink or be displaced by contraction by more than a certain distance in the direction opposite to the supply direction of the refrigerant.

On the other hand, since the former of the superconducting cable is cooled relatively slowly, the shrinkage rate is delayed, and therefore, shrinkage less than a certain distance is expected to occur during the supply time of the refrigerant.

The inner housing 2200 and the outer housing 2300 constituting the intermediate connection structure 2000 include an inner corrugated pipe 2400 and an outer corrugated pipe 2500 that can be flexibly deformed in the longitudinal direction of the cable to offset construction errors and the like. Since it is connected to the outer metal tube of the superconducting cable through the superconducting cable, the contraction force as described above will displace the entire intermediate connection structure 2000 in the opposite direction to the refrigerant supply direction, but the connection part 2100 accommodated in the inner housing is displaced relatively little. Collision between components (for example, the edge 2100s of the connection part 2100 having an expanded diameter between internal components including the edge 2200e of the inner housing) within the intermediate connection structure 2000 due to a change in location Or, since damage may occur, it is necessary to prevent the internal components of the intermediate connection structure 2000 from being changed even when the refrigerant is supplied and the contraction force is applied.

Accordingly, the intermediate connection structure 2000 according to the present invention includes a shrink-preventing member 2600 having both ends fixed to the outer surface of the superconducting cable and the outer housing 2300 of the intermediate connection structure 2000.

The shrinkage prevention member 2600 connects the inner metal tube 300 and the intermediate connection of the superconducting cable when cryogenic liquid refrigerant is supplied through the inner metal tube of any one superconducting cable connected through the intermediate connection structure 2000. The inner housing 2200 and the outer housing 2300 of the structure 2000 may support contraction force to shrink or displace in a direction opposite to the supply direction of the refrigerant.

As described above, the inner housing 2200 and the outer housing 2300 constituting the intermediate connection structure 2000 may be made of stainless steel, and the inner metal tube 500 and the outer metal tube of the superconducting cable 1000 600 may be made of aluminum or stainless material, and the shrinkage prevention member 2600 has one end fixed to the outer metal tube 600 of the superconducting cable and the other end fixed to the outer housing 2300. Since it is provided to prevent displacement due to shrinkage of the inner metal tube 300 and the intermediate connection structure 2000 of the superconducting cable, which may occur when the refrigerant is supplied, the shrinkage preventing member 2600 preferably has sufficient tensile force. .

In particular, the anti-shrinkage member 2600 is preferably made of a metal having greater tensile strength than the inner metal tube 500 and the outer metal tube 600, which may be made of aluminum or the like. For example, the shrinkage preventing member 2600 may be made of stainless steel or the like.

As shown in FIGS. 4 and 5 , the anti-shrinkage member 2600 may have a ring shape having an 'L' cross-section.

Here, since the anti-contraction member 2600 should resist contraction force in the longitudinal direction of the cable, that is, in the horizontal direction, it is preferable that the vertical height (b) of the anti-contraction member is greater than the width (a) in the horizontal direction. This is because when the width (a) of the anti-contraction member 2600 in the horizontal direction is large, the area in the horizontal direction of the anti-contraction member 2600 can be easily deformed when a contraction force is applied.

Here, since the inner housing 2200 and the outer housing 2300 constituting the intermediate connection structure 2000 are connected by a fixing member 2250, the shrinkage preventing member 2600 is attached to the outer metal tube and the outer housing 2300. Even if both ends are fixed, the contraction force can be supported.

As a result, one end of the anti-shrinkage member 2600 is fixed to the outer metal pipe 600 of the superconducting cable, and the other end is attached to the outer housing 2300 for vacuum insulation of the inside of the intermediate connection structure. It is fixed to provide an effect of preventing damage to the connection structure 2100 due to a difference in shrinkage between the inner metal tube 500 and the outer metal tube 600.

As described above, the intermediate connection structure of the superconducting cable according to the present invention prevents shrinkage of parts, etc. that may occur when shrinkage occurs due to refrigerant supply, even when the cable and junction box are connected with a corrugated pipe to offset errors in construction. Since it can be prevented through the member 2600, the effect of improving the stability of the system can be obtained.

Although this specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all of them should be considered to be included in the technical scope of the present invention.

2000 : Intermediate connection structure
2100: connection part
2200: inner housing
2250: fixing member
2300: outer housing
2400: inner corrugated pipe
2500: outer corrugated pipe
2600: shrinkage prevention member
1000: superconducting cable
100: core part
200: cooling unit
300: inner metal tube
500: vacuum part
600: external metal tube

Claims (12)

a core portion sequentially provided with a former, a superconducting conductor layer, an insulating layer, and a superconducting shielding layer; an inner metal tube accommodating a cooling unit for cooling the core unit with a liquid refrigerant through a cooling passage outside the core unit; And, in the intermediate connection device for intermediate connection between superconducting cables including; an outer metal tube defining a vacuum portion surrounding the outer side of the inner metal tube,
an inner housing internally connected to both cores of the superconducting cable and connected to an inner metal tube of the superconducting cable to accommodate a liquid refrigerant;
an outer housing for vacuum insulating the outside of the inner housing; and,
One end is fixed to the outer metal tube of the superconducting cable, and the other end is provided with a shrinkage prevention member fixed to the outer housing,
Superconducting cable intermediate connection device, characterized in that the vacuum area inside the outer housing surrounding the inner housing is binary. According to claim 1,
When liquid refrigerant is supplied through the inner metal pipe of any one superconducting cable between the inner housing and the outer housing, the inner housing connected to the inner metal pipe of the superconducting cable contracts in the direction opposite to the supply direction of the liquid refrigerant, and the outer housing and a fixing member connecting and fixing an outer surface of the inner housing and an inner surface of the outer housing so as to be shared with each other. According to claim 2,
The shrinkage prevention member supports a contraction force that the inner metal tube of the superconducting cable, the inner housing connected to the inner metal tube, and the outer housing connected to the inner housing and the fixing member are contracted in a direction opposite to the supply direction of the liquid refrigerant. Intermediate connection device of superconducting cable characterized by According to claim 1,
The intermediate connection device of a superconducting cable, characterized in that the shrinkage prevention member is composed of a ring shape having a 'L' shape in cross section. delete According to claim 1,
The outer metal tube of the superconducting cable is connected to the inner housing of the intermediate connection structure by an inner corrugated tube to form a first vacuum region communicating with the inner vacuum part of the outer metal tube of the superconducting cable, and the outer housing of the intermediate connection structure. An intermediate connection device for a superconducting cable, characterized in that connected to the outer corrugated pipe to form a second vacuum region therein. According to claim 6,
The first vacuum region surrounds both end regions of the inner housing of the intermediate connection structure and communicates with the vacuum portion of the superconducting cable, and the second vacuum region surrounds a circumferential surface of the inner housing of the intermediate connection structure. Intermediate connection device for cables. According to claim 6,
The outer metal pipe of the superconducting cable is connected to the inner corrugated pipe and the outer corrugated pipe by a connecting member. According to claim 1,
Wherein the tensile strength of the shrinkage prevention member is greater than the tensile strength of the outer metal tube of the superconducting cable. According to claim 1,
Intermediate connection device of a superconducting cable, characterized in that the height of the shrinkage prevention member in the vertical direction is greater than the width in the horizontal direction. A superconducting cable including a core part including a superconducting conductor layer, an inner metal tube accommodating a cooling part for cooling the core part with a liquid refrigerant through a cooling passage outside the core part, and an outer metal tube defining a vacuum part surrounding the outside of the inner metal tube. In the intermediate connection device for intermediate connection between,
In order to prevent damage to the connection structure due to a difference in shrinkage between the inner metal tube and the outer metal tube, one end is fixed to the outer metal tube of the superconducting cable, and the other end constitutes the outer shape of the intermediate connection structure and vacuum insulates the inside thereof. An intermediate connection device for a superconducting cable, comprising: an anti-shrinkage member fixed to an outer housing for a superconducting cable. According to claim 11,
Both cores of the superconducting cable are internally connected and further include an inner housing connected to an inner metal tube of the superconducting cable to accommodate a liquid refrigerant,
A fixing member connecting and fixing the outer surface of the inner housing and the inner surface of the outer housing so that the inner housing connected to the inner metal tube of the superconducting cable is contracted in the direction opposite to the supply direction of the liquid refrigerant to share the contraction force with the outer housing. An intermediate connection device of a superconducting cable, characterized in that.

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