JP4517879B2 - Superconducting cable - Google Patents

Description

  The present invention relates to a superconducting cable. In particular, the present invention relates to a superconducting cable that does not have a vacuum heat insulating structure or has a vacuum heat insulating structure, but can maintain heat insulating performance even if the vacuum breaks.

  As a superconducting cable, a superconducting cable shown in FIG. 8 has been proposed. FIG. 8 is a cross-sectional view of a three-core collective superconducting cable. The superconducting cable has a configuration in which three cores 110 are housed in a heat insulating tube 600.

  The cable core 110 includes a former 111, a superconducting conductor layer 112, an insulating layer 113, a shield layer 114, and a protective layer 115 in order from the center. The conductor layer 112 is formed by spirally winding a superconducting wire on a former 111 in multiple layers. Usually, the superconducting wire is a tape-like one in which a plurality of filaments made of an oxide superconducting material are arranged in a matrix such as a silver sheath. The insulating layer 113 is formed by winding insulating paper such as semi-synthetic insulating paper. The shield layer 114 is formed by spirally winding a superconducting wire similar to the conductor layer 112 on the insulating layer 113. For the protective layer 115, insulating paper or the like is used.

  On the other hand, the heat insulating pipe 600 has a structure in which a heat insulating material (not shown) is disposed between the double pipes composed of the inner pipe 610 and the outer pipe 620, and the inside of the double pipe is evacuated. An anticorrosion layer 630 is formed outside the heat insulating tube 600. Then, a refrigerant such as liquid nitrogen is filled and circulated in the former 111 (when the former is hollow) or the space formed between the inner tube 610 and the core 110, and the insulating layer 113 is impregnated with the refrigerant. State.

Japanese Patent Laid-Open No. 2002-140944 (FIG. 2)

  However, the above superconducting cable has the following problems.

(1) A vacuum insulation structure is required, and the cable becomes larger.
In order to obtain a vacuum heat insulating structure, it is necessary to use a heat insulating pipe having a double pipe structure and to evacuate the heat insulating pipe. For this reason, the thickness of the heat insulating tube is increased, and in particular, the outer diameter of the superconducting cable is increased. As a result, the manufacturing cost of the superconducting cable is also increased.

(2) The maintenance and management of the vacuum performance of the heat insulating tube is complicated.
By using a vacuum-insulated double-pipe insulation tube, it is necessary to maintain and manage the vacuum performance at all stages of manufacturing, installation and operation of superconducting cables. In particular, when an abnormality occurs in the vacuum performance of the heat insulating tube, it takes a lot of time to return to a predetermined vacuum state again. Depending on the situation, there may be a case where it is difficult to return to a predetermined vacuum state within a certain time. In this case, the temperature of the refrigerant cannot be maintained, and the power transmission function may be lost.

  The present invention has been made in view of the above circumstances, and a main object thereof is to provide a superconducting cable that retains a predetermined heat insulating characteristic without having a vacuum heat insulating structure.

  Another object of the present invention is to provide a superconducting cable that has a vacuum heat insulating structure but can maintain predetermined heat insulating characteristics even when the vacuum is broken.

  The present invention achieves the above object by using a heat insulating member other than vacuum heat insulating.

  The superconducting cable of the present invention includes a cable member in which a core having a superconducting conductor layer and an insulating layer is housed in a housing tube, a heat insulating member provided outside the cable member and maintained in a non-vacuum state, and a heat insulating member And a sealing member for preventing moisture from entering the device.

  By disposing a heat insulating member held in a non-vacuum state outside the cable member, it is possible to maintain a predetermined heat insulating characteristic without adopting a vacuum heat insulating structure. Further, by providing the heat insulating member with a seal member, it is possible to prevent moisture from entering the heat insulating member and maintain the heat insulating characteristics of the heat insulating member.

  Hereinafter, the superconducting cable of the present invention will be described in more detail.

  The superconducting cable of the present invention includes a cable member, a heat insulating member held in a non-vacuum state, and a seal member that prevents moisture from entering the heat insulating member.

<Cable member>
First, the cable member includes a core and a storage tube that stores the core. The core has at least a superconducting conductor layer and an insulating layer. Typically, a former, a superconducting conductor layer, an insulating layer, a shield layer, and a protective layer are provided in order from the center. The shield layer may also be composed of a superconducting wire.

  The former retains the superconducting conductor layer in a predetermined shape, and a pipe-shaped or stranded wire structure can be used. The material is preferably a nonmagnetic metal material such as copper or aluminum. When the former is pipe-shaped, the inside of the former can be a refrigerant flow path.

  The superconducting conductor layer is formed, for example, by spirally winding a wire made of a superconducting material on a former. A specific example of the superconducting wire is a tape-like one in which a plurality of filaments made of Bi2223 oxide superconducting material are arranged in a matrix such as a silver sheath. The winding of the superconducting wire may be a single layer or a multilayer. In the case of a multilayer structure, 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, manufactured by Sumitomo Electric Industries, Ltd.).

  The insulating layer is preferably formed by winding semi-synthetic paper such as PPLP (registered trademark of Sumitomo Electric Industries) laminated with polypropylene and kraft paper, or insulating paper such as kraft paper. Further, a semiconductive layer may be formed on at least one of the inner and outer circumferences of the insulating layer, that is, between the conductor layer and the insulating layer, or between the insulating layer and the shield layer. By forming the former inner semiconductive layer and the latter outer semiconductive layer, adhesion between the conductor layer and the insulating layer or between the insulating layer and the shield layer is improved, and deterioration due to the occurrence of partial discharge, etc. Suppress.

  Moreover, it is preferable to provide a shield layer outside the insulating layer. The shield layer may be made of a conductive material, and is preferably formed by winding a superconducting wire similar to the conductor layer around the outside of the insulating layer. By using a superconducting wire for the shield layer, it is possible to suppress a current having a phase opposite to that of the conductor current from flowing through the shield layer and leaking an alternating magnetic field to the outside.

  In addition, a cushion layer may be interposed between the former and the conductor layer. The cushion layer avoids direct contact between metals between the former and the superconducting wire, and prevents damage to the superconducting wire. In particular, when the former has a stranded wire structure, the cushion layer also has a function of making the former surface smoother. As a specific material of the cushion layer, insulating paper or carbon paper can be suitably used.

  On the other hand, the storage tube is a tube material that stores the core, and has a function of mechanically protecting the core. For example, a stainless or aluminum corrugated tube can be used as the storage tube. The storage tube basically does not need to have a heat insulation performance for maintaining the refrigerant temperature of the cable member, and the heat insulation performance described later bears the heat insulation performance. That is, it is preferable that the storage pipe is not provided with a heat insulating layer. With this configuration, the outer diameter of the storage tube can be made as small as possible.

  However, the storage tube may have a heat insulating function. In that case, any heat insulation structure of vacuum heat insulation and non-vacuum heat insulation may be used. When the vacuum insulation structure is adopted for the storage tube, the outer diameter of the cable member cannot be made smaller than that of the conventional superconducting cable. There is no problem because the heat insulating property of the cable member is maintained by the combination of the heat insulating property of the pipe and the heat insulating property of the heat insulating member. In order to reduce the outer diameter of the cable portion while adopting a vacuum heat insulation structure for the storage tube, it is conceivable to make the vacuum degree of the storage tube lower than the vacuum degree of the heat insulation tube of the conventional superconducting cable. Further, when a non-vacuum heat insulating structure is employed for the storage tube, this heat insulating property is lower than that required for maintaining the refrigerant temperature of the cable member. In this case, the non-vacuum heat insulating structure of the storage tube can be simplified, and the heat insulating characteristic necessary to maintain the refrigerant temperature of the cable member is a combination of the non-vacuum heat insulating structure of the storage tube and a heat insulating member described later. Secured.

<Heat insulation member>
A heat insulating member held in a non-vacuum state is disposed outside the storage tube. This heat insulating member basically has a heat insulating performance for maintaining the refrigerant temperature of the cable member. As the structure of the heat insulating member, at least one of a laminated heat insulating material and a filling heat insulating material is suitable. As the laminated heat insulating material, a so-called super insulation (which is obtained by laminating a metal foil and a plastic mesh) which is also used in a conventional superconducting cable can be suitably used. On the other hand, glass wool, foamed resin, sand, gravel, etc. can be suitably used as the filling heat insulating material.

  In particular, an airgel is desirable for the heat insulating member. Aerogel is a porous material in which a large number of extremely fine pores of nano-order are formed, and has high heat insulation properties. For example, silica airgel has a large number of pores with an average of 10 nm, its thermal conductivity is 10 mW / m-K (38 ° C., 1 atm), has a very high heat insulating property, and is extremely lightweight. As the airgel, for example, Pyrogel (trade name) manufactured by Aspen Aerogel, Inc., USA can be used.

  These heat insulating members can obtain superconducting cables according to various required characteristics by adopting any one of laminated heat insulating materials, filled heat insulating materials alone, and combinations of laminated heat insulating materials and filled heat insulating materials. Usually, since the laminated heat insulating material can cover the cable member so as to be wound, the outer shape of the laminated heat insulating material is easily formed into a cylindrical shape. On the other hand, the filled heat insulating material has a high degree of freedom in its material and outer shape, and various materials and outer shapes can be selected, and selection according to the installation environment, allowable dimensions, and allowable cost is possible. For example, it is desirable to arrange the laminated heat insulating material on the inner peripheral side of the heat insulating member and the filled heat insulating material on the outer peripheral side thereof. Superconducting cable that can effectively insulate radiant heat and obtain high heat insulation characteristics by arranging the laminated heat insulating material on the inner peripheral side, and is suitable for the installation environment by arranging the filled heat insulating material on the outer peripheral side. Can be selected.

<Seal member>
Said heat insulation member is distribute | arranged to the outer side of a cable member, and is sealed with a sealing member. The sealing member has a function of preventing moisture from entering the heat insulating member, thereby maintaining the heat insulating properties of the heat insulating member. Further, as described above, since the heat insulating member is, for example, a laminated heat insulating material or a filling heat insulating material, it is difficult to hold the shape by itself, and the sealing member does not hold the heat insulating member in a predetermined shape. It also has a function to make.

  The seal member is made of a material that can prevent moisture from entering. For example, a metal tube, a metal sheet, or a laminate material of a metal sheet and a plastic sheet can be suitably used. These metal sheets and laminate materials cover the outer periphery of the heat insulating member and join the sheet edges together by welding or adhesion so that moisture does not enter the sheet. Aluminum, aluminum alloy, stainless steel and the like can be suitably used for the metal tube and the metal sheet.

<Arrangement of multiple cable members>
In the superconducting cable as described above, the number of cable members may be one or more. When a plurality of cable members are used, it is preferable that the cable members are arranged close to each other. In particular, it is preferable to arrange a plurality of cable members close to each other in a common heat insulating member. Compared to the case where a plurality of cable members are independently arranged in the heat insulating member, the contact area between the cable member group and the heat insulating member is the case where a plurality of adjacent cable members are collectively arranged in the heat insulating member. (Per item) becomes smaller. Therefore, the intrusion heat per cable member can be reduced. In particular, other cable members adjacent to each cable member can be cooled to each other, and a further heat insulating effect can be expected.

  Ideally, the specific distance when the cable members are brought close to each other is zero, that is, the cable members are in contact with each other. However, even if there is an interval between the cable members, it is preferable that the interval is not more than the outer diameter of the cable member. By selecting such an outer diameter, the intrusion heat per one cable member can be reduced. More preferably, the distance between the cable members is not more than half of the outer diameter of the cable members.

<Combined refrigerant transport pipe>
In addition, the cable member may be provided with a refrigerant transport pipe in proximity. The refrigerant transport pipe here is a pipe line used for transporting various refrigerants. Typically, transport pipes such as liquid hydrogen, liquid oxygen, liquid nitrogen, or LNG are listed. These refrigerant pipes are usually used for transporting cryogenic refrigerants used in hydrogen stations and various plants, and more efficiently by placing them in a heat insulating member close to the cable member. Insulation (cooling) of the cable member can be performed.

  Similarly to the case where a plurality of cable members are arranged, it is preferable that the refrigerant transport pipe is arranged close to the cable members. Here, the “proximity” is preferably set to the same distance as the “proximity” between the cable members. That is, particularly when the refrigerant temperature of the refrigerant transport pipe is lower than the refrigerant temperature for cooling the superconducting conductor layer of the cable member, it can be expected to cool the cable member adjacent to the refrigerant transport pipe.

  However, depending on the relationship between the refrigerant temperature for cooling the superconducting conductor layer of the cable member and the refrigerant temperature of the refrigerant transport pipe, an auxiliary heat insulating structure may be formed in at least one of the cable member and the refrigerant transport pipe. This auxiliary heat insulating structure is a heat insulating structure for preventing each refrigerant of the cable member and the refrigerant transport pipe from deviating from an appropriate temperature mainly due to mutual heat transfer between the cable member and the refrigerant transport pipe.

  For example, if the refrigerant in the cable member is liquid nitrogen (boiling point approx. 77K, melting point approx. 63K) and the refrigerant in the refrigerant transport pipe is liquid hydrogen (boiling point approx. 20K), if the cable member and the refrigerant transport pipe are too close, There is a possibility that the liquid nitrogen is cooled too much and solidifies, or the liquid hydrogen in the refrigerant transport pipe is warmed and vaporized. Therefore, for example, it is preferable to provide an auxiliary heat insulating structure in the cable member to suppress the liquid nitrogen in the cable member from being cooled more than necessary or the liquid hydrogen in the refrigerant transport pipe from being warmed. In particular, if the heat insulation structure is such that the amount of heat by which the cable member is warmed by the intrusion heat from the outside and the amount of heat by which the cable member is cooled by the cold heat from the refrigerant transport pipe are balanced, both the cable member and the refrigerant transport pipe are It is more preferable because it can be easily maintained at an appropriate temperature.

  In addition, when the cable member refrigerant is liquid nitrogen (boiling point approx. 77K, melting point approx. 63K) and the refrigerant transport pipe refrigerant is liquefied natural gas LNG (boiling point approx. 110K, melting point approx. 90K), the cable member and refrigerant transport pipe configuration Depending on the distance, the liquid nitrogen of the cable member may be warmed and vaporized, or the LNG may be cooled more than necessary and solidify. Therefore, for example, it is preferable to provide an auxiliary heat insulating structure in the refrigerant transport pipe to prevent the liquid nitrogen in the cable member from being warmed or LNG from being cooled more than necessary. In particular, if the heat insulation structure is such that the amount of heat by which the refrigerant transport pipe is warmed by the intrusion heat from the outside and the amount of heat by which the refrigerant transport pipe is cooled by the cold heat from the cable member are balanced, both the cable member and the refrigerant transport pipe Is more preferable because it is easy to maintain at an appropriate temperature.

  The auxiliary heat insulating structure provided on the cable member or the refrigerant transport pipe may be a vacuum heat insulating structure or a non-vacuum heat insulating structure. When the auxiliary heat insulating structure is provided on the cable member, the storage tube itself constituting the cable member may be configured as a heat insulating layer, or a heat insulating layer may be formed outside the storage tube configuring the cable member. Moreover, when providing an auxiliary | assistant heat insulation structure in a refrigerant | coolant transport pipe, you may comprise the refrigerant | coolant transport pipe itself as a heat insulation layer, and you may form a heat insulation layer in the outer side of a refrigerant | coolant transport pipe. As the heat insulating material used for the auxiliary heat insulating structure, various known materials can be used as long as they satisfy necessary heat insulating characteristics.

<Pipe>
A configuration in which at least one of the cable member and the refrigerant transport path is housed in a pipe line and a heat insulating member is provided outside the pipe line is preferable. By storing the cable member in the pipe line, the “cable member or refrigerant transport pipe” and the “assembly of pipe line, heat insulating member, and seal member” can be manufactured separately, and the cable is later installed in the pipe line of the assembly A superconducting cable can be configured by inserting a member or a refrigerant transport pipe, and the efficiency of manufacturing and laying the cable can be improved. In particular, the cable member or the refrigerant transport pipe can be installed independently by inserting the cable member or the refrigerant transport pipe into a pipe line corresponding to each. In that case, since the pipe line is provided for each cable member or refrigerant transport pipe, it is possible to easily replace the stored items in the pipe line.

  It is desirable to construct the pipe line in an airtight manner. For example, the gap between the pipe and at least one of the cable member and the refrigerant transport pipe housed in the pipe is sealed at both ends of the pipe containing the cable member. At this time, it is desirable that the housing tube of the cable member has a vacuum heat insulating structure. If the inside of the pipe is airtight, when a storage tube having a vacuum sealing structure is used, it is possible to suppress a decrease in the heat insulating performance of the storage tube even if the vacuum sealing structure of the storage tube is broken. In particular, it is preferable to evacuate the inside of the pipe after sealing both ends of the pipe. With this configuration, even if the vacuum sealing structure of the storage tube is broken, the inside of the pipe line is kept in vacuum, so that the heat insulation performance of the cable member can be more effectively suppressed.

<Installation form of superconducting cable>
The superconducting cable of the present invention can use any laying form such as being buried in the ground or concrete, being placed in the air, or being installed on the ground surface. In particular, when buried in the ground or in concrete, since the soil around the superconducting cable has a heat insulating function, the heat insulation of the superconducting cable can be made more efficient.

<Types of superconducting cables>
The superconducting cable of the present invention can be used for both DC cables and AC cables. In particular, a direct current cable has no alternating current loss, and the loss is only intrusion heat. Therefore, a power line that minimizes the loss can be configured by efficient heat insulation using a heat insulating member.

According to the superconducting cable of the present invention, the following effects can be obtained.
(1) By placing a heat insulation member held in a non-vacuum state outside the cable member, it is possible to maintain a predetermined heat insulation characteristic without adopting a vacuum heat insulation structure, as in a conventional superconducting cable. There is no need to maintain and manage performance. As a result, A: The superconducting cable configuration can be simplified, B: The cable cost can be reduced, and C: As with conventional superconducting cables, power transmission is stopped due to abnormal vacuum performance of the insulation tube. The effect of being able to avoid the situation leading to is expected.

  (2) By providing the heat insulating member with the seal member, it is possible to prevent moisture from entering the heat insulating member and maintain the heat insulating characteristics of the heat insulating member.

  (3) By causing the heat insulating member to bear the heat insulating function, the cable member itself basically does not need to have the heat insulating function, and the diameter of the cable member can be reduced.

  (4) When a vacuum insulation structure is adopted for the cable member storage pipe, the insulation property of the cable member can be maintained by the insulation member even if the vacuum performance is abnormal, so a more reliable superconducting cable line is constructed. be able to.

  Embodiments of the present invention will be described below.

Example 1
First, the superconducting cable of the present invention will be described taking a case where it is buried in the ground as an example. FIG. 1 is a schematic view showing a buried state of the superconducting cable of the present invention in Example 1.

  As shown in FIG. 1, this superconducting cable has a single cable member 100, a heat insulating member 200 that covers the cable member 100, and a seal member 300 that covers the heat insulating member 200. It is buried in.

  As shown in FIG. 2, the single-core superconducting cable member 100 includes a former 111, a superconducting conductor layer 112, an insulating layer 113, a shield layer 114, a protective layer 115, and a storage tube 120 in order from the center. Among these constituent members, the former 111 to the protective layer 115 constitute the core 110, and the core 110 is accommodated in the accommodating tube 120. Further, a superconducting wire is used for the conductor layer 112 and the shield layer 114. The superconducting wire used for the cable member 100 is maintained in a superconducting state by circulating a refrigerant (here, liquid nitrogen) in the space between the core 110 and the storage tube 120.

  For the former 111, a plurality of insulated copper strands twisted together was used. By using the former 111 having a stranded wire structure, it is possible to simultaneously reduce AC loss and suppress an increase in temperature due to overcurrent. Also, in this example, the outer strand is made thinner than the center strand, so that the irregularities due to the grooves appear as small as possible on the outer circumference of the former 111.

  For the superconducting conductor layer 112, a Bi2223-based Ag-Mn sheath tape wire having a thickness of 0.24 mm and a width of 3.8 mm was used. This tape wire is wound in multiple layers on the former to form the superconducting conductor layer 112. In this conductor layer 112, the twist pitch of the superconducting wire is different in each layer. In addition, the current flowing in each layer can be equalized by changing the winding direction for each layer or for each of the plurality of layers.

  An insulating layer 113 is formed on the outer periphery of the superconducting conductor layer 112. The insulating layer 113 can be formed using, for example, an insulating tape (PPLP: registered trademark manufactured by Sumitomo Electric Industries, Ltd.) laminated with kraft paper and a resin film such as polypropylene.

  A shield layer 114 is provided on the insulating layer 113. The shield layer 114 is formed by winding a superconducting wire similar to that used for the conductor layer 112. In this shield layer 114, a current in the opposite direction is induced with approximately the same size as that of the conductor layer 112, thereby canceling out the magnetic field generated from the conductor layer 112 and preventing leakage of the magnetic field to the outside.

  Further, the protective layer 115 is formed on the shield layer 114 by wrapping kraft paper. The protective layer 115 mainly mechanically protects the shield layer 114 and electrically insulates from the storage tube 120.

  A core 110 composed of the former 111 to the protective layer 115 is housed in the housing tube 120. Here, a stainless corrugated tube is used for the storage tube 120. A refrigerant for cooling the superconducting wire is circulated in the storage tube 120. Further, the storage tube 120 does not have a double tube structure, and does not have a heat insulating structure for keeping the refrigerant at an extremely low temperature.

  On the other hand, the heat insulating member 200 is arranged so as to cover the periphery of the storage tube 120 (FIG. 1). Here, glass wool was used as the heat insulating member 200. The heat insulating member 200 is provided with such a thickness as to have a heat insulating characteristic necessary for maintaining the refrigerant in the cable member at a predetermined cryogenic temperature. Further, in this example, the heat insulating member 200 is arranged so that its cross-sectional shape is substantially rectangular. This cross-sectional shape may be determined according to the conditions of the installation location, and is not limited to a rectangle, but may be a circle or the like.

  Further, the outer periphery of the heat insulating member 200 is covered with a seal member 300. The sealing member 300 prevents moisture in the ground from entering the heat insulating member. In this example, a stainless steel sheet is wound around the outer periphery of the heat insulating member 200, and the edge of this sheet is joined by welding to form a seal member.

  According to the superconducting cable having such a configuration, since the vacuum heat insulating layer is not used, it is not necessary to maintain and manage the vacuum. In addition, in the conventional superconducting cable, there is a case where power transmission is stopped when an abnormality occurs in the heat insulating characteristics of the vacuum heat insulating layer. However, according to the cable of the present invention, such a situation can be avoided. Furthermore, the heat insulation performance of a heat insulation member can be maintained over a long period of time by using a sealing member.

  As a modification of this example, the heat insulating member 200 may be replaced with silica airgel. As this silica airgel, Pyrogel (trade name) of Aspen Aerogel, Inc. of the United States can be used. Since the silica airgel is lightweight and has very excellent heat insulating properties, the thickness of the heat insulating member 200 can be made thinner than other materials.

(Example 2)
Next, the superconducting cable of the present invention using a plurality of cable members will be described. FIG. 3 is a schematic view showing a buried state of the superconducting cable of the present invention in Example 2. In this example, differences from the first embodiment will be mainly described, and description of common configurations will be omitted.

  In this example, three cable members 100 similar to those in Example 1 are used, and these are arranged in a triangular shape inside the heat insulating member 200 in a contact state. Further, the heat insulation member 200 is configured by winding super insulation around a cable member group.

  As described above, by arranging the three cable members 100 close to each other in the heat insulating member, intrusion heat per one cable member can be reduced in addition to the effects of the first embodiment. This is because the total contact area with the heat insulating member 200 of the cable member group is smaller when the three strips are arranged in contact with each other than when the cable members 100 are individually arranged in the heat insulating member 200. This is because the cable members can cool each other.

(Example 3)
Next, the superconducting cable of the present invention will be described by taking as an example the case where a refrigerant transport pipe is combined with Example 2. FIG. 4 is a schematic view showing a buried state of the superconducting cable of the present invention in Example 3. In this example, differences from the second embodiment will be mainly described, and description of common configurations will be omitted.

  Here, the three refrigerant transport pipes 400 are disposed adjacent to the three cable members 100, and the cable member 100 and the refrigerant transport pipe 400 are disposed in the heat insulating member 200 so as to form an inverted triangle as a whole. Yes. The refrigerant transported by the refrigerant transport pipe 400 was liquid hydrogen (refrigerant temperature: about 20K).

  Also in the case of this example, the intrusion heat per one cable member can be reduced as in the second embodiment. In addition, since the refrigerant transport pipe 400 has a lower temperature than the cable member 100, the cable member 100 can be cooled by the refrigerant transport pipe 400.

  As a modification of this example, it is possible to provide the cable member 100 with an auxiliary heat insulating structure. If the refrigerant in the cable member 100 is liquid nitrogen (boiling point: about 77K, melting point: about 63K) and the refrigerant in the refrigerant transport pipe 400 is liquid hydrogen (boiling point: about 20K), the cable member 100 and the refrigerant transport pipe 400 are too close to each other. There is a possibility that the liquid nitrogen of the member 100 is cooled too much and solidifies, or the liquid hydrogen of the refrigerant transport pipe 400 is heated and vaporized. If the cable member 100 is provided with an auxiliary heat insulating structure, it is possible to prevent the liquid nitrogen of the cable member 100 from being cooled more than necessary or the liquid hydrogen of the refrigerant transport pipe 400 from being warmed. As an auxiliary heat insulating structure, a plastic jacket is provided on the outside of a stainless corrugated pipe that is a storage pipe.

Example 4
Next, a modified example of the superconducting cable of the present invention in which the configuration of the heat insulating member in Example 1 is changed will be described. FIG. 5 is a schematic view showing a buried state of the superconducting cable of the present invention in Example 4. Again, differences from the first embodiment will be mainly described, and description of common configurations will be omitted.

  In this example, the heat insulating member is composed of two kinds of materials. That is, the inner peripheral side close to the cable member was constituted by the laminated heat insulating material 210, and the outer peripheral side away from the cable member was constituted by the filled heat insulating material 220. More specifically, super insulation is used as the laminated heat insulating material 210 and foamed resin is used as the filling heat insulating material 220.

  By combining the laminated heat insulating material 210 and the filled heat insulating material 220, it is possible to effectively block both heat radiation and conduction and obtain high heat insulating properties.

(Example 5)
Next, a modified example of the superconducting cable of the present invention in which the cable member in Example 2 is housed in a pipeline will be described. FIG. 6 is a schematic view showing a buried state of the superconducting cable of the present invention in Example 5. Again, differences from the second embodiment will be mainly described, and description of common configurations will be omitted.

  In this example, each of the three cable members 100 is accommodated in the pipe line 500. According to this configuration, an assembly in which three cable members 100 are prepared, the common heat insulating member 200 is arranged outside the three pipe lines 500, and the outer periphery of the heat insulating member 200 is covered with the seal member 300. Is prepared separately. A superconducting cable can be obtained by individually housing each of the three cable members 100 in each pipeline 500 in the assembly. Therefore, a superconducting cable can be laid for each line.

  As a modification of the present example, there is a configuration in which the housing pipe of the cable member 100 is a vacuum heat insulating pipe made of a double pipe, and the pipe 500 is evacuated after the end of the pipe 500 is sealed. According to this configuration, even if the vacuum sealing of the storage tube is broken, the heat insulation characteristic of the cable member 100 is not deteriorated because the vacuum in the pipe line 500 is maintained. In this case, the degree of vacuum of the storage tube and the degree of vacuum in the pipe line may be lower than the degree of vacuum between heat insulation in the conventional superconducting cable. This is because the heat insulating property of the cable member 100 is maintained by the heat insulating member 200 that covers the outside of the cable member 100.

(Example 6)
Next, a modified example of the superconducting cable of the present invention in which the configuration of the cable member in Example 1 is changed will be described. FIG. 7 is a cross-sectional view of a cable member constituting the single-core superconducting cable of Example 6. Again, the differences from the first embodiment will be mainly described, and the description of the common configuration will be omitted.

  In this example, the storage pipe 120 of the cable member 100 in the first embodiment has a vacuum heat insulating structure made of a double pipe. That is, the storage tube 120 has an inner tube 121 and an outer tube 122, and a super insulation is arranged between both the tubes 121 and 122, and a vacuum is formed.

  According to the configuration of this example, since the vacuum insulation structure is used for the storage tube 120, it is not possible to make maintenance and management of vacuum unnecessary, but even if an abnormality occurs in the vacuum performance of the storage tube 120 by any chance. Since the heat insulating performance of the cable member 100 is maintained by the heat insulating member, a more reliable superconducting cable line can be constructed. In this example, a single-core superconducting cable has been described. However, in the case of a three-core superconducting cable, a structure similar to that shown in FIG.

  The superconducting cable of the present invention can be suitably used as a power transportation means.

It is the schematic which shows the embedment state of the superconducting cable in Example 1. It is a cross-sectional view of the cable member which comprises the superconducting cable of Example 1. FIG. It is the schematic which shows the embedment state of the superconducting cable in Example 2. It is the schematic which shows the embedment state of the superconducting cable in Example 3. It is the schematic which shows the embedment state of the superconducting cable in Example 4. It is the schematic which shows the embedment state of the superconducting cable in Example 5. It is a cross-sectional view of the cable member which comprises the superconducting cable of Example 6. It is a cross-sectional view of a conventional superconducting cable.

Explanation of symbols

100 Cable member 110 Core 120 Storage tube
111 Former 112 Superconducting conductor layer 113 Insulating layer 114 Shield layer
115 Protective layer 121 Inner pipe 122 Outer pipe
200 Insulation member 210 Laminated insulation 220 Filling insulation
300 Seal member
400 Refrigerant transport pipe
500 pipelines
600 Thermal insulation pipe 610 Inner pipe 620 Outer pipe 630 Anticorrosion layer
G Earth

Claims (9)

A cable member in which a core having a superconducting conductor layer and an insulating layer formed on the outer periphery of the superconducting conductor layer is housed in a housing tube;
A heat insulating member provided outside the cable member and maintained in a non-vacuum state;
Have a seal member for preventing the intrusion of moisture into the heat insulating member,
A superconducting cable characterized in that an inner peripheral side of the heat insulating member is a laminated heat insulating material and an outer peripheral side is formed of a filled heat insulating material . The superconducting cable according to claim 1, wherein the storage tube is not provided with a vacuum heat insulating layer. A plurality of cable members are arranged close to each other,
3. The superconducting cable according to claim 1 , wherein an interval between the cable members is equal to or less than an outer diameter of the cable member . Furthermore, a refrigerant transport pipe is arranged in the vicinity of the cable member, and the cable member and the refrigerant transport pipe are covered with a common heat insulating member ,
Spacing of the cable member and the refrigerant transporting tube, a superconducting cable according to any one of claims 1 to 3, characterized in that a smaller than the outer diameter of the cable member. At least one of the outside of the outer and the refrigerant transport tube of the cable members, prevent the vaporized solidifying is cooled more than necessary one refrigerant in the refrigerant of the cable member and the coolant transport tube, or warmed unnecessarily 5. The superconducting cable according to claim 4 , further comprising a heat insulating material for carrying out the operation. 5. The superconducting cable according to claim 4 , wherein at least one of the cable member and the refrigerant transport pipe is housed in a pipe line, and a heat insulating member is disposed outside the pipe line. 7. The superconducting cable according to claim 6 , wherein a gap between the pipe and at least one of the cable member accommodated in the pipe and the refrigerant transport pipe is airtight. 8. The superconducting cable according to claim 7 , wherein the inside of the conduit is evacuated. Superconducting cable according to any one of claims 1 to 8, characterized in that the heat insulating member is Airgel.

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