HK1069672B - Phase split structure of multiphase superconducting cable - Google Patents

Description

Phase separating member for multiphase superconducting cable

Technical Field

The invention relates to a separating member for separating a multiphase superconducting cable composed of a plurality of cable cores into respective segments (segments) containing said cable cores. More particularly, the present invention relates to a phase separating member of a superconducting multiphase cable to minimize or cancel a magnetic field generated outside each cable core.

Background

As one of superconducting cables produced using a superconducting wire formed of, for example, a bi-based high-temperature superconducting tape, a multi-core type multiphase superconducting cable manufactured by assembling a plurality of cable cores into one unit is under development.

Referring to fig. 4, the superconducting cable 100 includes three cable cores 102 twisted and accommodated in an insulation tube 101. The insulated pipe 101 has an outer pipe 101a and an inner pipe 101 b. The double pipe structure constituted by these outer pipe 101a and inner pipe 101b is provided with a heat insulating material (not shown) therein and a vacuum is generated between the double pipes. Each cable core 102 comprises, in order from the innermost component, a sizing tube 200, a superconductor 201, an electrically insulating layer 202, a shielding layer 203 and a shielding layer 204. The superconductor 201 is formed by winding a superconducting metal wire around the sizing tube 200 in layers in a spiral manner. The shield layer 203 is formed by being wound around the electric insulating layer 202 in a spiral manner by a method similar to that of the superconductor 201. In this shield layer 203, a current generated in a steady state has the same magnitude as a current flowing through superconducting wire 201 and is opposite to a direction in which it flows. The generated current induces a magnetic field that cancels the magnetic field generated by superconductor 201, such that there is little leakage of magnetic field outside of magnetic core 102. The gap 103 formed between the inner tube 101b and each cable core 102 generally provides a passage through which a coolant flows. A corrosion-resistant layer 104 made of polyvinyl chloride is provided around the heat insulating pipe 101.

For example, in the case where a plurality of multiphase superconducting cables are connected to each other, the multiphase superconducting cables are connected to a common conductive cable, or a terminal member formed with the multiphase superconducting cables, the multiphase superconducting cables are divided into respective sections corresponding to respective phases, that is, cable cores. In a distribution box which is kept at a low temperature, the cable is divided into a plurality of cable core sections, and the cable cores are fixed in the distribution box in a state of being separated from each other. A jig for maintaining a sufficient space between cables is disclosed, for example, in japanese laid-open patent No. 2003-009330.

For example, in the case where a plurality of multiphase normal conduction cables are connected to each other or a terminal member of the multiphase normal conduction cable is formed, the multiphase normal conduction cable is also divided into individual sections of the cable core, as with the multiphase superconducting cable. In this case, the common conductor cable is divided into a plurality of cable core sections without the above-described distribution box, so that the cable cores are naturally divided. The shield of each cable core is typically grounded in separate parts of the cable core in order to obtain a ground potential for each phase. This technique is described, for example, in page 645 of "Power Cable Technology Handbook, New edition" printed for the first time by Kihachiro Izuka, Kabushiki Kaisha Denkishoin March, first edition of March 1989.

However, with regard to the multiphase superconducting cable, it is not known or thought how to process the shield layer of each cable core at the divided portion, and therefore a specific method of appropriately processing the shield layer is also required. The shield layer of each cable core at the divided portion of the superconducting cable may be grounded similarly to the above-described ordinary conductive cable. However, the superconducting cable allows a very large current to flow compared to the general conductive cable, so that if the shielding layer is grounded as in the case of the general conductive cable, each shielding layer of the cable core may be connected through the ground. If the respective shield layers of the core of the superconducting cable are grounded separately and the shield layers are connected through the ground, the current flowing through the shield layers is smaller than the current flowing in the superconductor due to the high electrical connection resistance between the shield layers. The ultimate problem is that the shielding layer of each cable core cannot generate a magnetic field large enough to cancel the magnetic field generated by the superconductor of each cable core, and a large magnetic field is generated at the outside of each cable core.

Disclosure of Invention

An object of the present invention is to provide a phase separating member of a superconducting multiphase cable to minimize or cancel a magnetic field generated outside a plurality of cable cores.

The present invention achieves the above object by interconnecting the respective shield layers of a plurality of cable cores by means of a conductive material in such a manner that the shield layers are connected to each other with a low impedance.

Specifically, the phase separating member of the superconducting multiphase cable of the present invention comprises: a plurality of cable cores having respective shielding layers disposed around respective superconductors; a distribution box housing cable cores, each cable core extending from a collective portion in which the cable cores are assembled, the cable cores in the distribution box being spaced apart from each other; a conductive connecting portion which connects the respective shield layers of the cable cores in the distribution box to each other; and a fixing tool for fixing each of the plurality of cable cores in place.

If the individual shield layers of the cable core of the superconducting multiphase cable are connected to each other through the ground, the connection resistance between the shield layers is high. In this case, difficulty arises in generating a magnetic field by each shield layer of the cable core that cancels out a magnetic field generated from the superconductor of each cable core. Thus, the present invention connects the respective shield layers of the cable core to each other using a conductive element having a low connection resistance without connecting the shield layers via the ground in a manner of a high connection resistance.

The present invention is described in more detail below.

The invention is directed to a multiphase superconducting cable having a plurality of cable cores with respective shielding layers around respective superconductors. For example, the present invention is directed to a three-core type three-phase superconducting cable having three cable cores twisted and accommodated in an insulating tube. The superconducting cable of the present invention may be any known multiphase superconducting cable.

The present invention uses a breakout enclosure for housing a cable core section of a multiphase superconducting cable formed by dividing the superconducting cable into individual sections containing the cable core. In particular, in the distribution box, cable cores are housed which project from the collecting portion and are spaced apart from each other. Here, the collective portion refers to a portion of the multiphase superconducting cable in which a plurality of cable cores constituting the superconducting cable are assembled into the cable. The distribution box is filled with a coolant, such as liquid nitrogen, to cool the cable core so that the cable core is in a superconducting state. Therefore, the distribution box preferably has a heat insulating structure.

Each cable core in the distribution box can be fixed by means of a fixing tool. One example of the fixing tool is capable of fixing each of the cable cores and fixing the cable cores in a state of being spaced apart from each other. In particular, the fixing tool is suitably configured so that it can move in the distribution box with the elongation/contraction of the cable core.

According to the invention, the individual shielding layers of the cable cores accommodated in the distribution box are connected to one another by means of specific connecting portions, in particular conductive connecting portions formed from a conductive material. The conductive material is preferably copper or aluminum (resistivity p 2 × 10 at 77K), for example^-7Ω · cm). These materials have low electrical resistance even at temperatures close to the coolant temperature of the superconducting cable, for example, at the temperature of liquid nitrogen when liquid nitrogen is used as the coolant. The electrically conductive connecting portions connect at least respective portions of respective shielding layers of respective cable cores received in the distribution box in the longitudinal direction. The connecting portions may be shaped in such a way that the connecting portions are in contact in the circumferential directionAt least respective portions of the respective shielding layers of the cable core and enable the respective shielding layers of the cable core to be interconnected. If each of the shield layers of the cable core is formed of a plurality of superconducting strands, the connection portion is preferably formed in such a manner that the connection portion can be electrically connected to all the constituent superconducting strands. For example, the connecting portion is shaped to have a combination of a cylindrical member capable of covering the periphery of each shield layer of the cable core and a coupling member that couples the cylindrical members to each other. In particular, the coupling element is preferably a flexible element. More particularly, the coupling element is formed of woven (woven) material. The flexible coupling elements can be used to accommodate any movement that occurs when each cable core contracts due to cooling. The flexibility of the coupling element provides good workability in terms of limited space, such as internal assembly of the distribution box, and can absorb any dimensional deviations caused by assembly work (absorb).

Preferably, the conductive connecting portion and the shielding layer are connected with a low resistance at the time of connection. For example, they are suitably joined with solder. When the conductive connecting portion is connected to the shielding layer, if each cable core is provided with a shield layer, the shield layer is partially removed in advance to remove a portion of the shield layer where the connection is made.

The conductive connection portion may be connected to a shield layer of a cable core leading from a distribution box. The cable cores extending beyond the distribution box are provided with thermally insulating tubes filled with a coolant, such as liquid nitrogen, in order to be maintained in a superconducting state, as are the cable cores accommodated in the distribution box. Therefore, the member for connecting the conductive connecting portion to each of the shield layers of the cable core extending from the distribution box is complicated, and therefore, the present invention connects the conductive connecting portion to the cable core in the distribution box.

The conductive connection portions may be located at any position of each cable core in the distribution box. If the electrically conductive connecting portions are disposed in a position relatively close to the terminals of the divided cables (hereinafter referred to as separate terminals), the cable cores are further spaced from each other, thereby increasing the distance between the cable cores. In this case, workability in connecting the connection portions is improved, so this method is preferable. In contrast, if the conductive connecting portion is disposed relatively close to the collective portion, the cable cores cannot be substantially further separated, so the distance therebetween is relatively small. In this case, the conductive connecting portion is made compact, and since the connecting portion is located away from the separate terminal, the portion of the distribution box located closer to the separate terminal can be made smaller. In other words, the distribution box can be made more compact.

Preferably, the separating member of the present invention is formed not only at one end of the cable core (superconducting cable), but also at each of both ends of the cable core. If the separating member of the present invention is provided at each end of the superconducting cable, the respective shield layers of the cable core in each of the respective branch boxes at each terminal end of the cable core are connected to each other by the conductive connecting portion. Thus, in each of the respective shield layers of the cable core extending from the conductive connection portion at one end of the superconducting cable to the conductive connection portion at the other end of the superconducting cable, a current having substantially the same magnitude and opposite direction as a current flowing through the corresponding superconductor is induced in a steady state, and thus any leakage magnetic field outside the cable core is cancelled out. Most of the current having substantially the same magnitude and opposite direction to the current flowing through the superconductor flows through a portion of the shielding layer located closer to the collective portion with respect to the conductive connecting portion. Only a current smaller than that in the superconducting cable flows in the part of the shield layer between the conductive connecting portion and the separation terminal. Then, if the above-described heat insulating pipe provided around each of the cable cores extending from the distribution box is made of a low-resistance material, eddy current loss is caused due to a leakage magnetic field generated in the vicinity of the cable core between the electrically conductive connecting portion and the separation terminal. Then, in order to reduce or cancel the eddy current loss, the heat insulating pipe is preferably formed of a high-resistance material or an insulating material. The high impedance material preferably has a low temperature of at least 10 from room temperature to about 77K^-5Resistivity ρ of Ω · cm. High impedanceIs stainless steel (resistivity p is 4 × 10)^-5Omega cm to 8 x 10^-5Ω · cm). One example of an insulating material is FRP (fiber reinforced plastic).

Each respective shield of the cable core is grounded. Here, the shielding layers are preferably grounded together. Therefore, the present invention improves workability by grounding conductive connection portions that connect shield layers to each other so as to ground the shield layers together. Therefore, the present invention grounds the conductive connection portion connecting the shield layers to each other. If the separation member of the present invention is provided at both ends of the superconducting cable and the conductive connection parts at the respective ends are grounded, a closed loop is formed by the ground. Thus, only the conductive connection in the distribution box at one end is tapped.

The foregoing and other objects, features, forms and advantages of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 schematically illustrates a phase separating member of a superconducting multiphase cable of the present invention having a conductive connection portion located closer to a separation terminal;

fig. 2A is a cross-sectional view taken along line II-II of fig. 1, fig. 2B is a cross-sectional view of a portion of the core of the cable in the area C of fig. 1, and fig. 2C is a cross-sectional view of another form of the conductive connecting portion;

fig. 3A schematically shows a phase separating member of the superconducting multiphase cable of the present invention having a conductive connection portion located closer to the collective portion, and fig. 3B is a sectional view taken along III-III of fig. 3A;

fig. 4 is a sectional view of a three-core type three-phase superconducting cable.

Detailed Description

The following describes embodiments of the present invention.

First embodiment

As shown in fig. 1, this embodiment is described in connection with an example of a phase separation member of a three-phase superconducting cable 100 having three cable cores 102.

Referring to fig. 1, a phase separating member 150 of the superconducting multiphase cable of the present embodiment includes: three cable cores, each having a shielding layer disposed around a superconductor; a junction box 1 that houses the superconducting cable in a state where the cable cores 102 protruding from the collecting portion 110 where the three cable cores 102 are collected into the superconducting cable are separated from each other; and a conductive connecting portion 2 that connects the respective shield layers of the cable core 102 in the distribution box to each other.

The three-phase superconducting cable 100 of the present embodiment has the same structure as that shown in fig. 4. In particular, referring to fig. 4, a three-phase superconducting cable 100 is constructed by twisting three cable cores 102 each including, in order from the innermost portion, a sizing tube 200, a superconductor 201, an electrical insulation layer 202, a shield layer 203, and a shield layer 204, and which are accommodated in an insulation tube 101. The sizing tube 200 is constructed by twisting a plurality of copper wires each covered with an insulator. The superconductor 201 is constructed by spirally winding a wire in the form of a Bi 2223-based superconducting tape (a wire coated with Ag — Mn) in layers around the sizing tube 200. The shield layer 203 is constructed by spirally winding a wire in the form of a Bi 2223-based superconducting tape (clad with an Ag — Mn wire) in layers around the electrical insulating layer 202. The Electric insulating layer 202 is constituted by winding polypropylene laminated paper (pplp (r) manufactured by Sumitomo Electric Industries, ltd) around the superconductor 201. The protective layer 204 is constituted by winding kraft paper around the shield layer 203. The heat insulating pipe 101 has an outer pipe 101a and an inner pipe 101b each formed of a SUS corrugated pipe. The double pipe constituted by the outer pipe 101a and the inner pipe 101b is layered with a heat insulating material therein, and a vacuum is generated within the double pipe to realize a multi-layered heat insulating structure of the vacuum. Further, a corrosion resistant layer 104 of polyvinyl chloride is provided around the insulating tube 101.

Referring again to fig. 1, the three-phase superconducting cable 100 having the twisted cable core 102 assembled therein is divided into cable core segments by separating the cable cores 102 from each other so that the cable cores 102 can be individually controlled. The distribution box 1 accommodates these three cable cores 102 which are gradually separated from each other. Therefore, the superconducting cable 100 is inserted from one side (right side in fig. 1) of the distribution box 1, and the cable core 102 branched from the cable protrudes from the other side (left side in fig. 1) opposite to the side. The interior of the distribution box 1 is filled with a coolant, such as liquid nitrogen, for cooling the cable core with the coolant therein. Therefore, the distribution box 1 has a heat insulating structure with a heat insulating layer 1 a. The distribution box 1 of the present embodiment is cylindrical.

The cable cores 102 placed in the distribution box 1 extend from one side of the distribution box 1 (from the collective portion 110 of the superconducting cables 100) toward the other side of the distribution box 1 (toward the cable core 102 separation terminal), and the space between the cable cores 102 gradually increases to be constant. The cable core 102 of the present embodiment is fixed by a first fixing tool 10, a second fixing tool 11, and an intermediate fixing tool 12, wherein the first fixing tool 10 fixes the core at a position relatively close to the collective portion 110, the second fixing tool 11 fixes the core at an intermediate position, and the intermediate fixing tool 11 fixes the core between the first fixing tool 10 and the second fixing tool 11.

The first fixing tool 10 has a ring-shaped central portion, and three intermediate fixing tools 12 are fixed to the periphery of the ring-shaped portion. The first fixing tool is disposed between the cable cores 102 in such a manner that the center of the loop portion is substantially located at the center of the space surrounded by the three cable cores 102. The cable cores 102 are arranged at the respective intermediate fixing tools 12 such that the intermediate fixing tools 12 fix the cable cores 102 separated from each other.

The basic structure of the second fixing means 11 is almost similar to that of the first fixing means 10, and they differ only in that the ring portion of the second fixing means 11 is larger in diameter than that of the first fixing means 10. In the present embodiment, the slide member 11a is provided, which is substantially in point contact with the inner peripheral surface of the distribution box so as to be movable in the distribution box as the cable core 102 is extended/shortened. The slide member 11a is connected to an arbitrary portion on the periphery of the ring portion where the intermediate fixing tool 12 is not fixed. The cable cores 102 are fixed by the second fixing tool 11 in such a manner that the cable cores extend in the distribution box 1 toward the terminal portion 4 while the intervals between the respective cable cores are constant. Note that "close to the separation terminal" herein refers to a portion located closer to the terminal portion 4 with respect to the second fixing tool 11. Further, here, "close to the collective portion" refers to a portion located closer to the collective portion 110 with respect to the second fixing tool 11.

The intermediate fastening means 12 are each configured cylindrically by incorporating semi-arcuate elements, known colloquially as tubule (canaliculate) elements. In the present embodiment, the pair of tubule members covers the periphery of the cable core 102, and the peripheries of the tubule members and the periphery of the cable core 102 are connected by some clamping means such as a band (not shown) to fix the cable core 102 therein. The intermediate fixing tool 12 may have some through holes suitably provided therein to facilitate contact between the cable core 102 and the coolant in the intermediate fixing tool 12.

The present embodiment is characterized by a member that connects the respective shield layers of the cable core 102 to each other with the conductive connecting portion 2. In the present embodiment, each of the shield layers of the cable core 102 located closer to the separated terminal with respect to the second fixing tool 11 are connected to each other by the conductive connecting portion 2. Referring to fig. 2A and 2B, the conductive connecting portion 2 of the present embodiment includes a cylindrical member 2A that covers respective outer peripheries of the shielding layers 203 of the cable cores 102, and a coupling member 2B that couples the cylindrical members 2A to each other.

Each cylindrical member 2a is constituted by a pair of half-arc members which match in outer shape the outer shape of the cable cores 102 so that the cylindrical member 2a is attached to the outer periphery of the shield layer 203 of each cable core 102. Whereby the semi-arc shaped elements are merged to cover the outer circumference of the shielding layer 203. More particularly, as shown in fig. 2B, the shield layer 203 of the cable core is partially removed to partially expose the shield layer 203, and a pair of semi-arc elements is disposed on the exposed portion of the shield layer 203 to cover the cable core 102. The cylindrical element is made of copper. Although the paired half-arc members are connected by solder, they may be connected by a coupling member such as a screw. In addition, each cylindrical member 2a and the shield layer 203 of the cable core 102 are also connected by solder. Thus, the cylindrical member 2a is in contact with the superconducting tape-shaped wire constituting the shield layer 203.

The coupling member 2b connects the cylindrical members 2a to each other and is disposed between the cable cores 102 to hold the cable cores 102 in a state where the cable cores 102 are separated from each other. In the present embodiment, the coupling elements 2b are each formed of a copper braided material, as is the cylindrical element 2 a. The flexible coupling element 2b can be used to follow any movement of each cable core that may occur on cooling to cause shrinkage, and to facilitate connection with the cylindrical element 2a in the distribution box 1. Moreover, any deviations occurring in the operation of the connection can be absorbed. In the present embodiment, three coupling elements 2b are employed, and a cylindrical element 2A is connected to a corresponding end of each coupling element 2b, so that, as shown in fig. 2A, the conductive connecting portion 2 is formed in a triangular shape, and the cylindrical elements 2A are at respective vertexes (delta-type connection). In the present embodiment, the coupling element 2b and the cylindrical element 2a are connected by solder. In addition, they may be connected by means of coupling elements such as bolts. Further, as shown in fig. 2C, the conductive connecting portion 2 is configured such that the center element 2C thereof is disposed at the center of the triangle, and the cylindrical element 2a is disposed at the apex, and such that the coupling element 2b connects the center element 2C to the corresponding cylindrical element 2a (Y-connection).

According to the present embodiment, the heat insulating pipe 3 is provided around each cable core 102 protruding from the distribution box, the heat insulating pipe 3 is constituted by a double stainless steel corrugated pipe, and the heat insulating pipe is filled with the coolant like the distribution box. Therefore, each of the cable cores 102 extending from the distribution box 1 can be maintained in a superconducting state. The separate end of each cable core 102 is provided with a termination member 4 connectable to another cable core or a connecting device. The above-described features are also features of the second embodiment which will be described below.

The phase separating member 150 of the superconducting cable configured as described above has the conductive connecting portion 2 connecting the respective shield layers 203 of the cable core 102 so that the shield layers 203 are short-circuited with each other when a current flows through the cable. In particular, since the shield layers 203 are connected by a low connection resistance therebetween, the magnitude of the current flowing through each shield layer 203 is made substantially equal to the current flowing through each superconductor 201. Accordingly, a magnetic field that cancels out the magnetic field generated by each superconductor 201 can be generated in each shield layer 203, and accordingly generation of a large magnetic field outside the cable core 102 is reduced.

Further, according to the present embodiment, the conductive connecting portions 2 are connected at positions relatively close to the separation terminals, so that the conductive connecting portions 2 are easily connected at positions where the cable cores 102 are sufficiently separated from each other. Also, in the present embodiment, the heat insulating tube 3 provided around each of the cable cores 102 protruding from the distribution box 1 is made of a high-impedance material, so that even when a leakage magnetic field is generated around the cable cores 102 at a portion between the conductive connecting portion 2 and the terminal (see fig. 1), generation of eddy current can be reduced or minimized. In this way, any losses caused by eddy currents may be reduced.

In the present embodiment, the phase separating member 150 of the superconducting cable is provided at each respective end of each superconducting cable 100. At one end of the cable only the conductive connection 2 of the distribution box 1 is grounded. Specifically, a ground wire, which is pulled out to the outside of the distribution box 1 and grounded, is connected to the conductive connection portion 2 with solder, for example. The ground wire and the distribution box 1 are hermetically sealed to maintain airtightness. The conductive connecting portion 2 that connects the respective shield layers of the cable core 102 to each other is further grounded, so that the shield layers are commonly grounded. In addition, since only the conductive connection portion 2 at one end of the cable is grounded, the shield layer 203 of the cable core 102 is not connected through the ground.

Second embodiment

Referring to fig. 3A and 3B, the phase separating member 160 of the superconducting cable of the present embodiment has a substantially similar structure to the phase separating member 150 of the superconducting cable of the first embodiment shown in fig. 1, except that the conductive connecting portion 2' is disposed relatively close to the collecting portion 110 with respect to the second fixing tool 11, which will be described in detail later. Here, fig. 3A does not show the terminal portion.

The conductive connecting portion 2' of the second embodiment includes, as shown in fig. 3B: a cylindrical member 2a ' which covers the outer peripheries of the respective shield layers of the plurality of cable cores 102, and a coupling member 2b ' which couples the cylindrical members 2a ' to each other. The cylindrical member 2 a' of the present embodiment is constituted by a pair of copper semi-arc members, similarly to the first embodiment. The semi-arc elements of the cylindrical element 2 a' are arranged around the corresponding shielding layer exposed by partial removal of the shielding layer 204 of the cable core 102 and are bolted to cover the cable core 102. The cylindrical elements 2 a' are each connected to the corresponding shield layer 203 of the corresponding cable core 102 by solder.

The coupling element 2b 'of the present embodiment connects these cylindrical elements 2 a' to each other and is disposed between the cable cores 102. The coupling element 2b 'is formed of a triangular prismatic material cut into an arc corresponding to each portion of the respective vertex of the triangular section and is made of copper, as is the cylindrical element 2 a'. In the present embodiment, the cut portions of the coupling element 2B ' are connected with the corresponding cylindrical elements 2a ' to form conductive connection portions 2 ' having a triangular cross section, as shown in fig. 3B, and a cylindrical element 2a ' (delta connection) is provided on each vertex of the triangular cross section of the conductive connection portions 2 '. Although the coupling member 2b 'and the cylindrical member 2 a' are connected by solder in the present embodiment, they may be connected by a coupling member such as a bolt.

The phase separating member 160 of the superconducting cable configured as described above has the conductive connecting portion 2' that connects the respective shield layers of the plurality of cable cores 102 to each other, so that when a current flows through the cable, the connection resistance between the shield layers is reduced as achieved in the first embodiment. Thus, the magnitude of the current flowing through each of the shield layers is made substantially equal to the magnitude of the current flowing through each of the superconductors, and thus the magnetic field generated by the superconductor can be cancelled by the magnetic field generated in the shield layers. In this way, the generation of large magnetic fields outside the cable core can be reduced.

Further, since the conductive connecting portion 2' of the present embodiment is disposed at a position relatively close to the collective portion 110, the distance between the cable cores 102 is relatively short. Thus, the conductive connecting parts 2' can be made small and the spacing at a position relatively close to the separation terminal can be set smaller in the distribution box 1 with respect to the second fixing tool 11. In this way, the distribution box 1 can be made compact.

Third embodiment

Referring to fig. 1 and 3A, the first and second embodiments have been described in conjunction with a member having a stainless steel heat insulating tube 3 which is a high-resistance material and disposed around the outer periphery of each cable core 102 protruding from the distribution box 1. In the present embodiment, the heat insulating pipe is made of an insulating material of FRP (fiber reinforced plastic). With the phase separation member of the superconducting cable of the present embodiment, even if a leaked magnetic field is generated around the cable core 102 in the region from the conductive connection parts 2, 2' to the terminal part (see fig. 1), since the heat insulating pipes 3 provided around the respective peripheries of the cable core 102 protruding from the distribution box are made of an insulating material, eddy currents are not easily generated. This can effectively reduce the loss due to the eddy current.

As described above, with the phase separation member of the present invention, the respective shield layers of the plurality of cable cores are connected to each other with the conductive connecting portion at the portion where the cable is divided into the respective cable core sections. Thus, the generation of a large magnetic field outside the cable core can be effectively reduced.

Moreover, since the heat insulating tube of the high-impedance material or the insulating material is provided around the outer periphery of each of the cable cores relatively close to the separation terminal region, even if any leakage magnetic field is generated in the vicinity of the corresponding portion of the cable core located between the separation terminal and the conductive connecting portion, the generation of eddy current can be reduced or minimized. Thereby reducing any losses due to eddy currents.

While the invention has been described and illustrated in detail, it should be understood that: the drawings and examples are to be regarded as illustrative and exemplary only, and not as restrictive, the spirit and scope of the present invention being limited only by the appended claims.

Claims (7)

1. A phase separating member (150) of a multiphase superconducting cable, comprising:

a plurality of cable cores (102) having respective shielding layers (203) disposed around respective superconductors (201);

a junction box (1) that houses the plurality of cable cores (102) protruding from a collective portion (110), wherein the cable cores (102) are assembled in the superconducting cable, and the cable cores (102) in the junction box (1) are separated from each other;

a conductive connecting portion (2) that connects the respective shield layers (203) of the plurality of cable cores (102) to each other in the distribution box (1); and

-fixing means (10, 11, 12) for fixing each of said plurality of cable cores in position.

2. The phase separation member (150) of the multiphase superconducting cable according to claim 1, wherein the conductive connection portion (2) has cylindrical elements (2a, 2a ') covering respective outer circumferences of the shield layers (203) of the plurality of cable cores (102), and coupling elements (2b, 2b ') coupling the cylindrical elements (2a, 2a ') to each other.

3. Phase separation member (150) of a superconducting multiphase cable according to claim 2, wherein the coupling elements (2b, 2 b') are made of braided material.

4. Phase separation member (150) of a superconducting multiphase cable according to claim 1, wherein the conductive connection portion (2) is near a separation end of the cable core (102) in the distribution box (1).

5. The phase separation member (160) of the multiphase superconducting cable according to claim 1, wherein the conductive connection portion (2) is provided in the junction box (1) near the collective portion (110) of the cable core (102).

6. The phase separating member (150) of the superconducting multiphase cable according to claim 1, wherein a heat insulating pipe (3) is provided around an outer circumference of each of a plurality of cable cores (102) led out from the distribution box (1), and the heat insulating pipe (3) is made of a high-resistance material or an insulating material.

7. Phase separation member (150) of a superconducting multiphase cable according to claim 1, wherein a tap box (1) is provided at respective ends of the cable core (102) and the conductive connection portion (2) in the tap box at only one of the ends is grounded.