JP2005341767A - Terminal structure of superconducting cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small terminal structure of a superconducting cable in which Joule's loss and invasion heat can be reduced. <P>SOLUTION: The terminal structure of a superconducting cable comprises a conductor section 100 for a terminal, a refrigerant tub 21 for storing refrigerant, a body case 2 for containing the refrigerant tub while insulating thermally, a heat insulation pipe 5 having one end arranged in the refrigerant tub and the other end arranged on the outside of the body case, and an insulating section 4 arranged on the outer circumference at least at a part of the heat insulation pipe arranged in the body case. The conductor section 100 for terminal comprises a normal conductor 6 having one end arranged on the normal temperature side, and a superconductor 1 having one end connected with the other end of the normal conductor and the other end arranged in the refrigerant tub. The heat insulation pipe 5 is filled with refrigerant and the joint of the normal conductor 6 and the superconductor 1 is arranged in the heat insulation pipe 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a terminal structure of a superconducting cable disposed between a room temperature side and a cryogenic side. In particular, the present invention relates to a terminal structure of a small superconducting cable that enables large-capacity power transmission using a superconducting cable.

  As a terminal structure of a superconducting cable, for example, a structure shown in FIG. 5 is known (see Patent Document 1). FIG. 5 is a schematic configuration diagram showing a terminal structure of a conventional superconducting cable. In this terminal structure, a conductive connecting conductor 210 is connected to the end of a superconducting cable, and the end of the connecting conductor 210 is electrically connected to the room temperature side via a joint portion 270 (leading conductor portion). ) 220 is electrically connected. In the case of FIG. 5, the connection conductor 210 is connected to the lead conductor 220, but the end of the superconducting cable may be connected to the lead conductor without passing through the connection conductor.

  Further, the terminal structure includes a refrigerant tank 230 that houses the connection conductor 210 and one end side of the lead conductor 220 (connection side to the connection conductor 210), a vacuum container 240 that covers the refrigerant tank 230, and a room temperature side of the vacuum container 240. And a soot tube 250 projecting from the top.

  The connection conductor 210 and the lead conductor 220 are usually formed of a normal conductive material such as copper or aluminum, and the lead conductor 220 is disposed from the refrigerant tank 230 through the vacuum vessel 240 to the soot tube 250. Note that a heat insulating layer is formed around the refrigerant tank 230 by the vacuum container 240. The lead conductor 220 is built in an insulating portion 260 made of an insulating material such as FRP.

  The coolant tank 230 is provided with a joint portion 270, and is filled with a coolant such as liquid nitrogen that cools one end portion of the connection conductor 210 and one end portion of the lead conductor 220 connected to the joint portion 270. The soot tube 250 houses the other end of the lead conductor 220 and is filled with an insulating fluid such as insulating oil.

JP 2002-238144 A

  The superconducting cable is cooled to an extremely low temperature (for example, about 77K) with a refrigerant such as liquid nitrogen, thereby making the superconducting conductor portion in a superconducting state, reducing the resistance, and enabling large current transmission. On the other hand, since power equipment outside the superconducting cable line is used at room temperature, power is supplied to the power equipment by drawing current from the cryogenic temperature to room temperature at the end of the superconducting cable, or from the power equipment. Power is supplied to the superconducting cable.

  However, since the outside of the superconducting cable line is at room temperature, current cannot be drawn out in the superconducting state, and the room temperature side is passed through the cooled conductors (the connecting conductor 210 and the lead conductor 220 described above) made of normal conducting material. To draw current.

  Therefore, a large current flows through the lead conductor 220 connected to the normal temperature side so as to supply electric power equivalent to that of the superconducting cable to the normal temperature side. At this time, the lead conductor 220 has a larger resistance than a superconducting conductor in a cryogenic state, and the Joule loss becomes very large when a large current flows.

  In order to reduce Joule loss due to energization of a large current in the lead conductor, it is conceivable to increase the cross-sectional area (outer diameter) of the lead conductor to reduce the resistance. However, as the cross-sectional area of the lead conductor increases, heat penetration from the room temperature side to the cryogenic temperature side increases, and the superconducting state may not be sufficiently maintained on the cryogenic temperature side. Therefore, it is necessary to reduce the heat intrusion in order to sufficiently maintain the superconducting state.

  However, for example, if the cooling capacity is increased by placing a large refrigerator in the refrigerant tank, etc., in addition to increasing the size of the terminal structure, the energy required to maintain high cooling capacity becomes excessive, and superconducting cables are used. The effect to do becomes small.

  Also, if the length of the connection conductor 210 and the lead conductor 220 is sufficient for thermal insulation without installing a large refrigerator, the entire length of the connection conductor and the lead conductor becomes long, and the lead conductor In addition to an increase in cross-sectional area, the length also increases. For this reason, as in the case described above, the terminal structure is enlarged and it is difficult to make it practical. Furthermore, since the Joule loss increases even if the heat intrusion is reduced by increasing the length of the lead conductor, the effect of reducing the power transmission loss is reduced.

  In addition, when the cross-sectional area of the lead conductor is increased, the outer diameter of the bushing (insulating portion) is increased accordingly. At this time, the one end side of the bushing arranged in the refrigerant tank also has a problem of mechanical strength such that the shrinkage stress at the time of cooling by the refrigerant becomes large and is easily broken.

  From the above, the conventional terminal structure has a problem that it is difficult to reduce the size when trying to reduce both the Joule loss and the intrusion heat from the normal temperature side to the extremely low temperature side.

  Therefore, an object of the present invention is to provide a small terminal structure of a superconducting cable while reducing Joule loss and power transmission loss due to heat penetration.

  The present invention is a terminal structure of a superconducting cable connected to the superconducting cable in order to transmit electric power between the superconducting cable and the room temperature side.

  The present invention includes a terminal conductor, a refrigerant tank in which refrigerant is stored, a main body case for insulating and storing the refrigerant tank, one end disposed in the refrigerant tank, and the other end disposed outside the main body case. A heat insulating pipe and an insulating portion disposed on an outer periphery of at least a portion of the heat insulating pipe disposed in the main body case are provided.

  The terminal conductor portion includes a normal conductive conductor having one end disposed on the normal temperature side and a superconducting conductor having one end connected to the other end of the normal conductive conductor and the other end disposed in the refrigerant tank. The heat insulating tube is filled with a refrigerant, and a connection portion between the normal conducting conductor and the superconducting conductor is disposed.

  The superconducting conductor of the terminal conductor portion may be connected to the connection conductor via a joint portion or the like. In this case, the connecting conductor is connected to the end of the superconducting cable. Moreover, you may make it connect the superconducting conductor of the terminal conductor part via the joint part to the edge part of a superconducting cable not via a connection conductor.

  The superconducting conductor of the terminal conductor portion may be, for example, a configuration in which a wire made of a Bi2223 series superconducting material is spirally wound on a solid former or a configuration in which the same wire is wound on a hollow former. it can. When the wire is wound spirally, it may be a single layer or a multilayer, and in the case of a multilayer, an interlayer insulating layer may be provided. The interlayer insulating layer may be provided by winding insulating paper such as kraft paper or semi-synthetic insulating paper such as PPLP (registered trademark). When connecting the connection conductor to the terminal conductor, the connection conductor may be a superconducting conductor or a normal conducting conductor.

  A part of the superconducting conductor is arranged in the refrigerant tank provided in the main body case, and the superconducting conductor arranged in the refrigerant tank is cooled. In addition, when connecting a connecting conductor to the terminal conductor, this connecting conductor is also arranged in the refrigerant tank, and when there is no connecting conductor, the end of the superconducting cable is arranged. An example of the refrigerant stored in the refrigerant tank is liquid nitrogen in order to maintain the superconducting state of the terminal conductor portion.

  Furthermore, in the terminal structure of the present invention, it is preferable that the main body case constitutes a vacuum vessel, and the refrigerant tank is disposed in the vacuum vessel. Thus, since a heat insulation layer can be formed around a refrigerant tank by arranging a refrigerant tank in a vacuum vessel, the superconducting state of a superconducting conductor can be maintained efficiently. The refrigerant tank and the main body case are preferably made of a metal such as stainless steel having excellent strength. The refrigerant in the refrigerant tank may be circulated in a pressurized state.

  One end of the heat insulating tube is disposed in the refrigerant tank, and the other end is disposed outside the main body case. The portion of the heat insulation pipe that is disposed outside the main body case refers to, for example, a portion that is disposed inside the soot pipe and a portion that protrudes from this soot pipe when the soot pipe is attached to the main body case. For the heat insulating tube, it is possible to use a heat insulating material (for example, super insulation) interposed between a double corrugated tube made of a stainless outer tube and an inner tube and keep the double tube in a vacuum state. preferable.

  The insulating portion is disposed on the outer periphery of at least a portion of the heat insulating pipe disposed in the main body case. Specifically, it is preferable that the length of the insulating portion is shorter than that of the heat insulating tube, one end is disposed in the refrigerant tank, and the other end is disposed outside the main body case. When attaching a soot tube to the main body case, it is preferable that the portion of the insulating portion disposed outside the body case is stored in this soot tube so that it does not come out of this soot tube.

  An insulating part that can withstand the potential difference between the voltage applied to the terminal conductor and the ground potential is used. The insulating part may be formed only of an insulating material such as an insulating synthetic resin, or may be configured such that an insulating material is provided on the outer periphery of a metal cylinder such as stainless steel. For example, in the former case, the insulating portion may be formed integrally with the heat insulating tube. In the latter case, a heat insulating tube is arranged inside the metal cylinder. Examples of the insulating material include an insulating rubber material such as ethylene propylene rubber, reinforced fiber plastic (FRP), and the like. FRP is preferable because it has higher insulation performance.

  In the case where the insulating portion is configured to include an insulating material on the outer periphery of a metal cylinder such as stainless steel, it is preferable to form an airtight space between the metal cylinder and the heat insulating tube. And it is preferable to fill this space part with inert gas, such as helium gas which is not liquefied with the refrigerant | coolant of a refrigerant tank. By filling the inert gas in this way, it is possible to prevent frost from forming on the outer wall of the heat insulating tube or the inner surface of the metal tube in this space.

  Further, the connection portion between the superconducting conductor and the normal conducting conductor in the terminal conductor portion is disposed in the heat insulating tube. In this case, by connecting the superconducting conductor and the normal conducting conductor, and inserting the superconducting conductor and the normal conducting conductor inside the heat insulating tube, the connecting portion of the superconducting conductor and the normal conducting conductor is disposed in the heat insulating tube. Can do. With the superconducting conductor and the normal conducting conductor connected, the room temperature side opening of the heat insulating tube is sealed so that the refrigerant does not leak from the heat insulating tube.

  As the refrigerant filled in the heat insulating tube, it is preferable to use the same refrigerant as that filled in the refrigerant tank, and for example, nitrogen can be used.

  Furthermore, it is preferable to provide a heat insulating portion on the outer periphery of the portion of the heat insulating pipe where the insulating portion is not provided. The portion of the heat insulating tube where the insulating portion is not disposed is a portion that is disposed outside the main body case and is affected by room temperature. In the case where a soot pipe is provided, this heat insulating part is preferably provided outside the soot pipe. The heat insulating part is formed of a heat insulating material such as urethane resin or glass wool, for example. By this heat insulating part, it becomes easy to attach a temperature gradient from the normal temperature side to the cryogenic side of the normal conductor of the terminal conductor part, and the normal conductive conductor gradually rises in temperature from the end connected to the superconductor to the normal temperature side, The heat that enters the superconducting conductor can be reduced.

  In the case where the heat insulating portion is provided in this manner, the heat insulating portion can make the temperature gradient from the low temperature side end portion of the normal conducting conductor to the normal temperature side in the terminal conductor portion a desired gradient. As a result, it becomes easy to set the position of the connection portion between the normal conducting conductor and the superconducting conductor in the heat insulating tube at a position where the heat penetration from the room temperature side and the Joule loss can be balanced.

  Furthermore, the heat insulating pipe may be provided with a partition wall in the pipe near the connecting portion between the superconducting conductor and the normal conducting conductor, or may be communicated.

  If the heat insulation pipe is left in communication, a temperature gradient will occur due to the temperature difference between the superconductor and the normal conductor, and the inside of the low-temperature pipe will be mostly liquid refrigerant (for example, liquid nitrogen). Mostly gas refrigerant (gaseous nitrogen).

  When the partition wall is provided, the normal temperature side pipe may be filled with a gaseous refrigerant such as nitrogen gas. In this case, the temperature is higher than the liquid refrigerant (liquid nitrogen, e.g., about 77K) charged on the low temperature side and lower than the normal temperature, e.g., on the normal temperature side so that the gaseous refrigerant can be maintained at about 170K. A temperature control device may be connected.

  In the terminal structure of the present invention described above, the terminal conductor portion extending from the normal temperature side into the refrigerant tank is connected to the normal conductive conductor having one end disposed on the normal temperature side, and one end connected to the other end of the normal conductive conductor. An end is provided with a superconducting conductor disposed in the refrigerant tank. Furthermore, the connection portion between the normal conductor and the superconductor of the terminal conductor portion is disposed in a heat insulating tube filled with a refrigerant. Since the terminal structure of this invention becomes such a structure, the power transmission loss by the Joule loss of the normal conducting conductor in the terminal conductor part and the heat | fever penetration | invasion from the outside can be made small.

  The heat insulation pipe may be formed separately on the low temperature side and the normal temperature side, and the two heat insulation pipes may be connected after the connection between the superconducting conductor and the normal conductive conductor, or the low temperature side and the normal temperature side. May be formed integrally in a continuous manner. In the case of a continuously formed heat insulating tube, the number of assembling steps is reduced and the structure is simplified.

  Further, the inside of the heat insulation pipe may be communicated with the refrigerant tank, and the refrigerant filled in the refrigerant tank may be supplied inside the heat insulation pipe. In this way, by sharing the refrigerant in the refrigerant tank as the refrigerant to be filled in the heat insulation pipe, it is not necessary to separately provide a cooling device for cooling the refrigerant in the heat insulation pipe, and the system can be simplified.

  Furthermore, it is preferable to form a coolant channel inside the superconducting conductor in the terminal conductor. For example, the refrigerant flow path can be constituted by using a hollow former or the like for the superconducting conductor, and the refrigerant flow path can be formed by the hollow former. In this case, the refrigerant is filled in the refrigerant flow path of the superconducting conductor. As described above, if the superconducting conductor is also cooled from the inside by the refrigerant, the superconducting conductor can be cooled more efficiently and the superconducting state can be maintained more satisfactorily.

  When a refrigerant flow path is formed in the superconducting conductor in the terminal conductor, the refrigerant flow path of the superconducting conductor and the inside of the heat insulating pipe are communicated with each other at the connection portion between the superconducting conductor and the normal conductive conductor, and the inside of the heat insulating pipe is further connected. You may make it communicate in a refrigerant tank. At this time, it is preferable to connect the supply means which supplies the refrigerant | coolant in a refrigerant tank to a refrigerant flow path.

  In the case where the coolant channel is formed in the superconducting conductor, the end of the superconducting conductor and the end of the normal conducting conductor are connected with a connection sleeve so as to be spaced apart from each other. Then, a communication hole is formed in the connection sleeve for communicating the space formed between the superconducting conductor and the normal conducting conductor with the outside of the connection sleeve. The supply means can be configured, for example, by providing a cooling device and a pump outside the main body case, and connecting the cooling device and the pump to the inside of the refrigerant tank and the refrigerant flow path of the superconducting conductor via the refrigerant supply passage.

  With the supply means, the refrigerant in the refrigerant tank is taken out of the main body case and supplied to the cooling device, and the refrigerant cooled by the cooling device is supplied into the refrigerant channel through the supply passage to form the connection sleeve. It flows out from the communication hole to the inside of the heat insulation pipe. Then, due to the forced outflow of the refrigerant from the refrigerant flow path, the refrigerant in the heat insulating pipe flows out from the low temperature side opening of the heat insulating pipe into the refrigerant tank, and the refrigerant can be circulated. Due to the circulation of the refrigerant, it is possible to always supply the cooled refrigerant into the superconducting conductor, and also to circulate the refrigerant in the heat insulating pipe, so that the superconducting conductor can be cooled more efficiently.

In the present invention, the superconducting conductor is arranged in a heat insulating tube so that one end is connected to the normal conducting conductor, but the terminal structure includes a refrigerant tank, a vacuum vessel formed by a main body case, and a soot tube. In this case, the superconducting conductor can be arranged so as to extend from the refrigerant tank to the soot pipe through the heat insulating layer in the vacuum vessel. Fill the pipe with an insulating fluid such as insulating oil or SF ₆ gas.

  The superconducting cable connected to the terminal structure of the present invention may be a single-phase superconducting cable having one cable core having a superconducting conductor or a multiphase superconducting cable having a plurality of the cable cores. In the latter case, for example, a three-core one-piece three-phase superconducting cable in which three cable cores are twisted and stored in a heat insulating tube can be used. A known single-phase superconducting cable or multiphase superconducting cable may be used.

  The terminal structure of the superconducting cable according to the present invention has a normal conductor having one end disposed on the normal temperature side of the terminal conductor portion, one end connected to the other end of the normal conductor, and the other end disposed in the refrigerant tank. The superconducting conductor is provided, and the connection portion between the normal conducting conductor and the superconducting conductor is arranged in a heat insulating tube filled with a refrigerant.

  As a result, since the terminal conductor portion disposed in the case body can be cooled to a cryogenic temperature, a part of the terminal conductor portion can be a superconducting conductor having a low resistance, and the terminal conductor portion disposed in the case body. Can be thinned. Furthermore, since the end of the normal conducting conductor connected to the superconducting conductor is disposed in the heat insulating tube, the normal conducting conductor is given a temperature gradient from the normal temperature side to the cryogenic temperature side.

  In addition, by providing a heat insulating portion on the outer periphery of the portion of the heat insulating pipe where the insulating portion is not disposed, the heat insulating portion can regulate the temperature distribution of the normal conductive conductor so that the Joule loss and heat penetration of the normal conductive conductor can be balanced. Since the optimum state can be obtained, the power transmission loss can be reduced as a whole.

  In addition, since the cross-sectional area (outer diameter) of the conductor of the terminal conductor part covered with the insulating part can be reduced, the outer diameter of the insulating part compared to the case where all the normal conductors are used as the conductors of the conventional terminal conductor part. Can also be reduced. Therefore, the terminal structure itself can be reduced in size without reducing the power supplied to the superconducting cable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment of the present invention.

(First embodiment)
FIG. 1 is a schematic partial configuration diagram showing a terminal structure of a superconducting cable of the present invention according to the first embodiment, and FIG. 2 is a partial cross-sectional view showing the vicinity of a normal temperature side end portion of a terminal conductor portion. This terminal structure includes a terminal conductor portion 100 that is electrically connected to the end portion of the superconducting conductor of the superconducting cable via a connecting conductor 11, and a main body case 2 in which the terminal conductor portion 100 is accommodated. .
The terminal conductor portion 100 includes a superconducting conductor 1 connected to the connecting conductor 11, and a normal conducting conductor 6 connected to the other end of the superconducting conductor 1 and having one end disposed on the normal temperature side. The main body case 2 forms a vacuum container, and the refrigerant tank 21 is disposed inside. A soot tube 3 is attached to the main body case 2.

  The superconducting conductor 1 of the terminal conductor portion 100 uses a configuration in which a wire made of a Bi2223 series superconducting material is spirally wound on a former. One end of the superconducting conductor 1 is disposed in the refrigerant tank 21 and the other end is disposed in the heat insulating tube 5.

  In the present embodiment, the connecting conductor 11 is also configured such that a wire made of a Bi2223 superconducting material is spirally wound on a former. The connecting conductor 11 may be formed of a normal conductive material.

  In the present embodiment, the end portion of the superconducting conductor 1 and the end portion of the connecting conductor 11 are connected in the refrigerant tank 21 by the joint portion 12.

  The main body case 2 and the refrigerant tank 21 are made of stainless steel, and a heat insulating layer is formed around the refrigerant tank 21 by evacuating the main body case 2. The heat insulation layer formed around the refrigerant tank 21 efficiently maintains the cryogenic state of the refrigerant tank 21.

  The refrigerant tank 21 is filled with a refrigerant such as liquid nitrogen. Although not shown, the refrigerant in the refrigerant tank 21 is circulated.

  The heat insulation pipe 5 has a low temperature side end arranged in the refrigerant tank 21, and the room temperature side protrudes from the main body case 2 and is inserted into the soot pipe 3 and then protrudes from the soot pipe 3.

  The heat insulation pipe 5 is made of a double corrugated pipe made of a stainless outer pipe and an inner pipe with a heat insulating material (e.g., super insulation) interposed therebetween, and the inside of the double pipe is kept in a vacuum state. Yes. In the heat insulating pipe 5, a part of the superconducting conductor 1 and the normal conducting conductor 6 is arranged so that a connection portion between the superconducting conductor 1 and the normal conducting conductor 6 is arranged.

  In the present embodiment, a cylindrical insulating portion 4 is provided outside the heat insulating tube 5 to withstand a potential difference between the voltage applied to the terminal conductor portion 100 and the ground potential. The insulating part 4 is arranged so that one end thereof is inserted into the refrigerant tank 21 and the other end is inserted into the inside of the soot tube 3 through the heat insulating layer of the main body case 2.

  As shown in the enlarged partial sectional view of FIG. 2, the insulating portion 4 includes an insulating material 42 made of FRP having excellent insulating properties on the outer periphery of a cylindrical body 41 made of stainless steel. A copper first shield plate 25 is provided at an end portion (end portion of the cylindrical body 41) arranged on the room temperature side of the insulating portion 4.

  The normal temperature side opening of the soot tube 3 is sealed with the second shield plate 31 made of copper, and the low temperature side opening is sealed with the wall surface of the main body case 2 so that the inner surface of the soot tube 3 and the outer surface of the insulating portion 4 are sealed. An insulating fluid such as insulating oil is filled in a space formed between the two.

  Between the cylindrical body 41 of the insulating part 4 and the heat insulating tube 5, a first shield plate 25 provided at the normal temperature side end of the insulating part 4 and a third shield for sealing the low temperature side opening of the insulating part 4. An airtight space is formed by the plate 26, and this space is filled with an inert gas such as helium gas.

  In the present embodiment, the normal conducting conductor 6 is connected to the superconducting conductor 1, and the normal temperature side end of the normal conducting conductor 6 is inserted into the pipe from the low temperature side opening in the heat insulating pipe 5. With the superconducting conductor 1 and the normal conducting conductor 6 connected, the room temperature side opening of the heat insulating tube 5 is sealed together with the normal conducting conductor 6 by the fourth shield plate 27 so that the refrigerant does not leak from the inside of the heat insulating tube 5. I have to.

  As shown in FIG. 2, the normal conducting conductor 6 and the superconducting conductor 1 are connected by a connection sleeve 7 made of a normal conducting material, for example, copper. In this embodiment, as shown in FIGS. 1 and 2, this connecting portion is close to the position where the first shield plate 25 sealing the insulating portion 4 is disposed. Any position that can maintain the superconducting state of the superconducting conductor 1 in the pipe 5 is not limited to this position. The heat insulating tube 5 is airtightly penetrated through a hole formed in the central portion of the first shield plate 25.

  In the present embodiment, the low temperature side opening of the heat insulating pipe 5 is opened in the refrigerant tank 21 so that the refrigerant in the refrigerant tank 21 flows into the heat insulating pipe 5. By sharing the refrigerant in the refrigerant tank 21 as the refrigerant to be filled in the heat insulation pipe 5, it is not necessary to separately provide a cooling device for cooling the refrigerant in the heat insulation pipe 5, and the system can be simplified.

  Further, a heat insulating portion 8 is provided on the outer periphery of the normal temperature side end portion of the heat insulating tube 5 (portion protruding to the outside from the soot tube 3). By providing the heat insulating portion 8, the temperature of the normal conducting conductor 6 gradually increases from the end connected to the superconducting conductor 1 to the normal temperature side, so that the heat entering the superconducting conductor 1 can be further reduced. For the heat insulating material of the heat insulating portion 8, urethane resin, glass wool, or the like is used.

  Further, a radiation fin 81 is provided on the normal conductive conductor 6 on the normal temperature side of the position where the heat insulating portion 8 is disposed, and the heat generated from the normal conductive conductor 6 in the heat insulating portion 8 is dissipated by the heat radiation fin 81. Thus, the current capacity can be secured.

  Although the superconducting cable used in this embodiment is not shown, for example, a three-core three-phase superconducting cable in which three cable cores are twisted and housed in a heat insulating tube is used. The heat insulating tube of this cable has a structure in which a heat insulating material is disposed between the double tubes composed of the outer tube and the inner tube, and the inside of the double tube is evacuated. Each cable core includes a former, a superconducting conductor, an electrical insulating layer, a shield layer, and a protective layer in order from the center.

  In the present embodiment, the end portion of the superconducting cable core is connected to the connecting conductor 11, and the connecting conductor 11 is connected to the end portion of the superconducting conductor 1 through the joint portion 12. It should be noted that the superconducting cable core and the superconducting conductor 1 may be connected at the joint without using the connecting conductor.

  According to the terminal structure of the superconducting cable as described above, the terminal conductor portion 100 extending from the room temperature side into the refrigerant tank, the normal conductor 6 having one end arranged on the room temperature side, and the other end of the normal conductor 6 One end is connected to the superconducting conductor 1 and the other end is disposed in the refrigerant tank 21. Further, the connection portion between the normal conducting conductor 6 and the superconducting conductor 1 of the terminal conductor portion 100 is disposed in the heat insulating tube 5 filled with the refrigerant.

  As a result, the superconducting state of the superconducting conductor 1 can be maintained by the heat insulating tube 5, so that a superconducting conductor having a small resistance and a small diameter can be used for a part of the terminal conductor portion.

  In addition, in the present embodiment, the temperature gradient is also given to the normal conductor 6 by the heat insulating pipe 5, so that the heat intrusion from the normal conductor 6 to the superconductor 1 can be prevented, and the Joule loss of the normal conductor 6 can be prevented. Power transmission loss due to heat intrusion from outside can be reduced.

  In addition, since the heat insulating part 8 is provided outside the main body case and the insulator pipe in the heat insulating pipe 5, the temperature distribution of the normal conductive conductor 6 is in an optimum state so that the Joule loss and heat penetration of the normal conductive conductor 6 can be balanced. Can be.

  Moreover, since a superconducting conductor can be used for the terminal conductor, the cross-sectional area (outer diameter) of the conductor can be reduced, so that the conductor is built in compared to the case where only the normal conductor is used for the terminal conductor. The outer diameter of the insulating part 4 can be reduced. Therefore, the terminal structure itself can be reduced in size without reducing the power supplied to the superconducting cable. In addition, since the outer diameter of the insulating portion 4 can be reduced by the amount that the terminal conductor portion can be made thinner, cracking of the insulating portion 4 during cooling can be reduced.

  As described above, the present invention supplies the current amount equivalent to the amount of current flowing through the superconducting cable to the superconducting conductor of the terminal conductor portion, so that the normal conduction of the terminal conductor portion is achieved in a state where Joule loss and heat penetration are balanced. Electric power can be supplied from the conductor to the room temperature side. As a result, even if the terminal structure is downsized, the thermal insulation performance is not deteriorated, and the transmission loss such as Joule loss can be reduced.

  In the above embodiment, a multiphase superconducting cable is shown, but a single-phase superconducting cable can also be used. This also applies to the following embodiments.

(Second embodiment)
In the first embodiment, the superconducting conductor of the terminal conductor portion has a solid configuration. However, in the second embodiment shown in FIGS. 3 and 4, the superconducting conductor has a coolant channel inside. It is configured. FIG. 3 is a schematic partial configuration diagram showing the terminal structure of the superconducting cable of the present invention according to the second embodiment, and FIG. 4 is a cross-sectional view of the periphery of the connecting portion between the superconducting conductor and the normal conducting conductor.

  The basic structure of the terminal structure shown in FIG. 3 is the same as the terminal structure of the superconducting cable of the first embodiment shown in FIG. 1, and the same components are denoted by the same reference numerals and description thereof is omitted.

  In the second embodiment, the superconducting conductor 10 of the terminal conductor portion has a refrigerant flow path 13. Specifically, a wire made of a Bi2223 series superconducting material is spirally wound on a hollow former, and the hollow portion of the former is used as the refrigerant flow path 13. In this case, the refrigerant is filled in the refrigerant flow path 13 of the superconducting conductor 10.

  As shown in FIG. 4, the refrigerant flow path 13 of the superconducting conductor 10 is opened at the normal temperature side end of the superconducting conductor 10. The end portion of the superconducting conductor 10 and the end portion of the normal conducting conductor 6 are connected by the connection sleeve 7 with a predetermined gap therebetween.

  The connection sleeve 7 is formed with a communication hole 71 that communicates the space formed between the superconducting conductor 10 and the normal conducting conductor 6 with the outside of the connection sleeve 7. The refrigerant flow path 13 is communicated with the space between the superconducting conductor 10 and the normal conducting conductor 6 and is communicated with the heat insulating pipe 5 through the communication hole 71 of the connection sleeve 7.

  Furthermore, the terminal structure of the present embodiment is provided with a supply means 9 for supplying the refrigerant in the refrigerant tank 21 into the refrigerant flow path 13. The supply means 9 includes a cooling device 91 and a pump 92 provided outside the main body case 2, a first refrigerant supply passage 93 that takes out the refrigerant from the refrigerant tank 21 to the outside of the main body case by the pump 92, and is supplied to the cooling device 91. A second refrigerant supply passage 94 is provided for supplying the refrigerant cooled by the device 91 to the refrigerant flow path 13 of the superconducting conductor 10.

  The superconducting conductor 10 is connected to the connecting conductor 11 and the joint portion 12 in the refrigerant tank 21, and the superconducting conductor 10 is connected to the joint portion 12 through the joint portion 12. A refrigerant is supplied to the refrigerant flow path 13 of the conductor 10.

  The refrigerant sent from the refrigerant tank 21 to the cooling device 91 via the first refrigerant supply passage 93 is cooled by the cooling device 91 and then supplied from the second refrigerant supply passage 94 into the refrigerant flow channel 13 to be refrigerant. The fluid is discharged from the normal temperature side end of the flow path 13 and flows out from the communication hole 71 formed in the connection sleeve 7 to the inside of the heat insulating pipe 5.

  Then, due to the forced outflow of the refrigerant into the heat insulation pipe 5, the refrigerant in the heat insulation pipe 5 flows out from the low temperature side opening of the heat insulation pipe 5 into the refrigerant tank 21, and the refrigerant can be circulated. By circulating the refrigerant, it is possible to always supply the cooled refrigerant into the superconductor 10, and the refrigerant in the heat insulating pipe 5 is also circulated through the refrigerant tank, so that the superconductor 10 is cooled more efficiently. Can do well.

  In this way, if the superconducting conductor 10 is also cooled from the inside by the coolant, the superconducting conductor 10 can be cooled more efficiently, and the superconducting state can be maintained more satisfactorily.

  The terminal structure of the present invention is suitable for forming a terminal portion of a superconducting cable connected to an electric device or a normal conducting cable used at room temperature, and is used for either a single-phase superconducting cable or a multiphase superconducting cable. be able to. Further, it can be used for either an AC line or a DC line.

It is a schematic partial block diagram which concerns on 1st embodiment which shows the terminal structure of this invention superconducting cable. It is an expanded sectional view showing the normal temperature side edge part circumference of a superconducting conductor in a first embodiment. It is a schematic partial block diagram based on 2nd embodiment which shows the terminal structure of this invention superconducting cable. It is an expanded sectional view which shows the normal temperature side edge part periphery of the superconducting conductor in 2nd embodiment. It is a schematic block diagram which shows the terminal structure of the conventional superconducting cable.

Explanation of symbols

100 Terminal conductor
1,10 Superconducting conductor
11 Connecting conductor 12 Joint 13 Refrigerant flow path
2 Body case
21 Refrigerant tank
25 1st shield plate 26 3rd shield plate 27 4th shield plate
3 Steel pipe 31 Second shield plate
4 Insulating part 41 Tubular body 42 Insulating material
5 Insulated pipe 6 Normal conductor 7 Connection sleeve 71 Communication hole
8 Thermal insulation 81 Radiating fin
9 Supply means
91 Cooling device 92 Pump 93 First refrigerant supply passage
94 Second refrigerant supply passage
210 Connection conductor 220 Lead conductor 230 Refrigerant tank 240 Vacuum container
250 Steel pipe 260 Insulation part 270 Joint part

Claims (5)

A terminal conductor,
A refrigerant tank in which refrigerant is stored;
A body case for insulating and storing the refrigerant tank;
One end is disposed in the refrigerant tank, and the other end is disposed outside the main body case;
Insulating portion disposed on the outer periphery of at least the portion disposed in the main body case in the heat insulating pipe,
The terminal conductor is
A normal conducting conductor having one end disposed on the room temperature side;
One end is connected to the other end of the normal conducting conductor, and the other end comprises a superconducting conductor disposed in the refrigerant tank
A terminal structure of a superconducting cable, wherein a refrigerant is filled in a heat insulating tube and a connecting portion between a normal conducting conductor and a superconducting conductor is disposed.   The terminal structure of a superconducting cable according to claim 1, wherein a heat insulating portion is provided on an outer periphery of a portion of the heat insulating pipe where the insulating portion is not provided.   The terminal structure of a superconducting cable according to claim 1 or 2, wherein the inside of the heat insulating pipe is communicated with the refrigerant tank.   The terminal structure of a superconducting cable according to any one of claims 1 to 3, further comprising a coolant channel inside the superconducting conductor in the terminal conductor.   The refrigerant flow path of the superconducting conductor in the terminal conductor and the inside of the heat insulating pipe are communicated at the connecting portion between the superconducting conductor and the normal conductive conductor, and the inside of the heat insulating pipe is communicated with the refrigerant tank, The terminal structure of a superconducting cable according to claim 4, wherein a supply means for supplying the refrigerant in the refrigerant tank is connected.

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