JP2014146584A - Superconductive cable and superconductive cable rail track - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive cable that never allows early stopping of running due to the trouble in a cooling system.SOLUTION: A superconductive cable 1 includes: an internal member housing tube 20; an outer insulating tube 30; an inner coolant 20C; and an outer coolant 30C. The internal member housing tube 20 houses a cable internal member 10 in the inside. The outer insulating tube 30 houses the internal member housing tube 20 in the inside. The inner coolant 20C is packed in the inside of the internal member housing tube 20 and cryogenically cools the cable internal member 10. The outer coolant 30C is packed in the inside of the outer insulating tube 30 and in the outside of the internal member housing tube 20. Of the packed unit of the outer coolant 30C in the inside of the outer insulating tube 30, at least a portion in the longitudinal direction of the outer insulating tube 30 acts as a vaporization allowable section that allows the vaporization of the outer coolant 30C, and treats the intruded heat from outside environment via the outer insulating tube 30, by the vaporization of the outer coolant 30C in the outer insulating tube 30.

Description

  The present invention relates to a superconducting cable including a cable internal member having a superconducting conductor, and a superconducting cable line including the superconducting cable.

  A superconducting cable including a cable inner member having a superconducting conductor is known. The superconducting cable of Patent Document 1 has a configuration in which a cable internal member having at least a superconducting conductor and an electrical insulating layer provided on the outer periphery of a former is housed in a heat insulating tube, and a liquid refrigerant is circulated inside the heat insulating tube (so-called low temperature insulation). Mold configuration). On the other hand, in the superconducting cable of Patent Document 2, a cable inner member having a superconducting conductor on the outer periphery of the former is housed in a heat insulating pipe having an electric insulating layer provided on the outer periphery, and a liquid refrigerant is circulated inside the heat insulating pipe. It has a configuration (so-called room temperature insulation type configuration). In any configuration, by circulating and cooling the liquid refrigerant in the heat insulation pipe that houses the cable internal member, the intrusion heat from the external environment into the heat insulation pipe is processed, and the superconducting conductor of the cable internal member is maintained at a very low temperature. Can do. In a superconducting cable that performs AC power transmission, the superconducting conductor itself generates heat due to AC loss, so it is necessary to handle the heat generated by the superconducting conductor in addition to intrusion heat. The superconducting conductor can be kept at a very low temperature by treating the intrusion heat from the environment.

  The liquid refrigerant in the above configuration has a predetermined temperature / pressure condition that does not vaporize in the circulation path (that is, the occurrence of vaporization of the liquid refrigerant in the circulation path means that this condition is not met). Circulated at a flow rate. This is because if there is a vaporized gas in the circulation path, the circulation of the liquid refrigerant is hindered, and the superconducting conductor may not be maintained below the allowable temperature. The temperature of the liquid refrigerant, which is a vaporization factor, rises due to heat generated by the superconducting conductor in addition to intrusion heat in DC transmission and intrusion heat in AC transmission. The flow rate of the liquid refrigerant is set so that the temperature rise is within a predetermined range, and the liquid refrigerant whose temperature has risen is cooled by the cooling system, so that the liquid refrigerant in the circulation path is maintained in a state that does not vaporize. . The allowable temperature is a temperature that is lower than the critical temperature of the superconducting conductor and can satisfy the predetermined current capacity (A).

JP 2011-226526 A JP 2012-174403 A

  However, the superconducting cable has a problem that power transmission by the superconducting cable becomes difficult due to a trouble in the cooling system. For example, when the circulation pump that circulates the liquid refrigerant stops for some reason, the liquid refrigerant whose temperature has risen due to intrusion heat from the external environment or the like cannot be moved to the cooling system. If so, the temperature of the liquid refrigerant for cooling the superconducting conductor of the cable internal member rises, and the superconducting conductor cannot be maintained below the allowable temperature. In particular, superconducting cables for AC power transmission have heat generated by the superconducting conductor itself in addition to intrusion heat, so superconducting cables for AC power transmission are more difficult to transmit in a shorter time than superconducting cables for DC power transmission. I fall. Therefore, a drastic solution that can avoid an early shutdown due to a trouble in the cooling system is desired.

  The present invention has been made in view of the above circumstances, and one of its purposes is to use a superconducting cable in which power transmission does not stop early due to a trouble in a cooling system including a refrigerant circulation system, and the superconducting cable. It is to provide a superconducting cable line.

  The superconducting cable of the present invention is a superconducting cable including a cable inner member having a superconducting conductor, and includes a cable portion, an inner refrigerant, and an outer refrigerant. The cable portion includes a cable internal member, an internal member storage tube that stores the cable internal member therein, and an outer heat insulating tube that stores the internal member storage tube therein. The inner refrigerant is filled in the inner member storage pipe and cools the superconducting conductor provided in the cable inner member to a cryogenic temperature. The outer refrigerant is filled inside the outer heat insulating tube and outside the inner member housing tube, and suppresses the temperature rise of the inner member housing tube. In this superconducting cable, of the outer refrigerant filling portion inside the outer heat insulating tube, at least a part of the outer heat insulating tube in the longitudinal direction is a vaporization permissible section that allows vaporization of the outer refrigerant. By treating the intrusion heat from the external environment through the pipe by vaporizing the outer refrigerant in the outer heat insulating pipe, the temperature rise of the inner member housing pipe is suppressed.

In the superconducting cable of the present invention, the inner refrigerant may be simply filled in the inner member housing pipe, or may be circulated in the closed circulation path. On the other hand, the outer refrigerant is not circulated in the closed circulation path. This is because it is difficult to circulate the outer refrigerant in the closed circulation path because it is assumed that vaporization gas of the outer refrigerant is generated in the outer refrigerant filling section, and vaporization gas of the outer refrigerant is generated in that section. is there. Based on the above points, the states of the inner and outer refrigerants of the superconducting cable of the present invention are summarized as follows.
[1]
The inner refrigerant is filled in the inner member storage pipe (here, “the inner refrigerant is filled” means that the inner refrigerant is simply stored without flowing, or the inner refrigerant is in the inner member storage pipe. Any of the states flowing from one end to the other).
The outer refrigerant is filled in the filling portion of the outer heat insulating pipe (here, “filled with the outer refrigerant” means that the outer refrigerant is simply stored without flowing, or the outer refrigerant is in the filling portion. Any of the states flowing from one end to the other).
[2]
The inner refrigerant is circulated in the inner member storage tube. The inner refrigerant that has flowed from one end to the other end in the internal member storage pipe passes through a return pipe or a pipe of another superconducting cable and is sent to one end in the internal member storage pipe while being cooled by the cooling system.
The outer refrigerant is filled in the filling portion of the outer heat insulating pipe (including a state in which the outer refrigerant flows from one end to the other end of the outer refrigerant filling portion).

  With the superconducting cable of the present invention having the above configuration, even if a trouble occurs in the cooling system, the time from the occurrence of the trouble to the stop of power transmission can be extended longer than in the conventional configuration. Since the intrusion heat from the external environment can be processed by vaporizing the outer refrigerant, the superconducting conductor of the cable inner member can be maintained at a very low temperature. The temperature of the internal refrigerant depends on its external temperature (that is, the temperature of the external refrigerant).

  As the superconducting cable of the present invention, a form provided with a refrigerant replenishing mechanism for replenishing the outer refrigerant lost due to vaporization can be mentioned.

  In the configuration in which the intrusion heat is processed by vaporization of the outer refrigerant, the outer refrigerant continues to decrease. Therefore, it is necessary to replenish the outer refrigerant in order to operate the superconducting cable soundly. If a refrigerant replenishment mechanism for automatically replenishing the outer refrigerant is provided, the superconducting cable can be stably operated.

  Examples of the superconducting cable of the present invention include a form in which a vaporization allowable section is formed over the entire length of the outer heat insulating tube.

  When the entire length of the outer heat insulating pipe is used as the vaporization allowable section, it is only necessary to add the outer refrigerant into the outer heat insulating pipe, and the pump for sending the outer refrigerant into the outer heat insulating pipe can be omitted.

  As the superconducting cable of the present invention having the refrigerant replenishment mechanism, the outer refrigerant is pressurized and supplied by the refrigerant replenishment mechanism, and the outer refrigerant is in an overcooled state in the outer refrigerant charging section except for the vaporization allowable section. The form used as the supercooling area can be mentioned.

  As a specific application example of the above configuration, a superconducting cable having a large height difference can be cited. For example, in a superconducting cable in which the height gradually increases from one end of the superconducting cable toward the other end, the pressure of the outer refrigerant on one end side becomes very high. When the pressure of the outer refrigerant increases, the boiling point of the outer refrigerant increases, so that the temperature of the inner refrigerant surrounded by the outer refrigerant tends to increase. In such a case, there is a risk that the superconducting conductor cannot be properly maintained at an extremely low temperature by the inner refrigerant. Therefore, in the case of a superconducting cable whose height gradually increases from one end side to the other end side, for example, the outer refrigerant is pressurized and supplied from one end side to the other end side, and the outer refrigerant extends from one end side to the middle. Is a supercooling section where the flow rate is a predetermined flow rate, and the remainder is a vaporization allowable section. With such a configuration, since the outer refrigerant always flows in the supercooling section where the pressure of the outer refrigerant becomes high, the temperature rise of the outer refrigerant in the supercooling section is suppressed.

  An example of the superconducting cable of the present invention is that the inner refrigerant is pressurized and filled without being circulated.

  According to the above configuration, there is no need to provide a configuration for circulating the inner refrigerant, for example, a return pipe or a high-power circulation pump, and the superconducting cable can be simplified.

  As the superconducting cable of the present invention, the inner refrigerant can be circulated.

  According to the above configuration, the superconducting conductor can be more reliably maintained at an extremely low temperature equal to or lower than a predetermined temperature by the inner refrigerant. In particular, the configuration in which the inner refrigerant is circulated is effective for a superconducting cable that performs AC power transmission, as will be described later.

  Examples of the superconducting cable of the present invention include a form in which the superconducting cable is used for direct current power transmission.

  Since there is no AC loss in a superconducting cable for direct current power transmission, the only heat that must be processed to maintain the superconducting conductor at an appropriate temperature is intrusion heat from the external environment. Therefore, in the superconducting cable that performs direct current power transmission, the inner refrigerant may not be circulated or may be circulated.

  Examples of the superconducting cable of the present invention include a form in which the superconducting cable is used for AC power transmission.

  In a superconducting cable for AC transmission, the superconducting conductor generates heat due to AC loss. Therefore, in order to process the heat generated in this superconducting conductor, it is better that the inner refrigerant is circulated. By circulating the inner refrigerant, the superconducting conductor can be reliably maintained at a predetermined temperature or lower.

  As the superconducting cable of the present invention, a form provided with a discharge mechanism having a discharge pipe for discharging the vaporized gas of the outer refrigerant from the vaporization allowable section can be mentioned.

  If the vaporized gas stays in the outer refrigerant filling portion and a gas pool is generated, heat intrusion may not be processed at the position of the gas pool. On the other hand, by setting it as the structure provided with the said discharge mechanism, the expansion of the gas pool in the filling part of an outer side refrigerant | coolant can be suppressed, and the process of the invasion heat by an outer side refrigerant | coolant can be made more reliable. Depending on where the discharge mechanism is provided in the cable portion, there are two cases, when only the vaporized gas is discharged from the discharge mechanism and when the outer refrigerant containing the vaporized gas is discharged from the discharge mechanism.

  As the superconducting cable of the present invention including the discharge mechanism, the discharge mechanism can be provided at a high-side terminal of the cable portion.

  If the cable portion does not meander up and down, the vaporized gas generated in the vaporization allowable section moves to the high-side terminal. Further, even if the cable portion meanders up and down, the vaporized gas moves from the high altitude side terminal to the meandering portion to the high altitude side terminal. Thus, if a discharge mechanism is provided at the high-end terminal, the vaporized gas can be efficiently removed from the outer refrigerant charging portion.

  As a superconducting cable of the present invention having a discharge mechanism, a plurality of discharge mechanisms may be provided along the longitudinal direction of the cable portion.

  When the cable portion meanders up and down, there is a possibility that a gas pool of vaporized gas may be generated in a portion where the cable portion is curved so as to protrude vertically upward. Therefore, by providing a plurality of discharge mechanisms along the length direction of the cable portion, in particular, by providing a discharge mechanism at the curved portion where there is a possibility that a gas pool may occur, the expansion of the gas pool can be suppressed. Even when the cable portion does not meander up and down, the vaporized gas can be quickly discharged if there are a plurality of discharge mechanisms along the length direction of the cable portion. In addition, when the whole installation place of a cable part is horizontal, the location which made the cable part meander up and down intentionally may be provided, and the discharge | emission mechanism may be provided in the location.

  As the superconducting cable of the present invention including the discharge mechanism, the discharge mechanism may include a guide member that guides the vaporized gas to the discharge pipe.

  By providing the guide member, it is possible to quickly discharge the vaporized gas from the vaporization allowable section, and it is possible to effectively suppress the expansion of the gas reservoir in the outer refrigerant filling portion. When the vaporized gas is discharged from the discharge pipe in a state where it is mixed with the outer refrigerant, the discharged liquid refrigerant may be returned to the inside of the outer heat insulating pipe again.

  Examples of the superconducting cable of the present invention including the discharge mechanism include a liquefaction mechanism for reliquefying the vaporized gas and an introduction mechanism for introducing the reliquefied refrigerant into the outer heat insulating pipe again as an outer refrigerant.

  By reusing the vaporized gas as the outside refrigerant, it is possible to reduce the trouble of supplementing the vaporized outside refrigerant.

  As a superconducting cable of the present invention having a discharge mechanism, a storage tank connected to a discharge pipe of the discharge mechanism and storing an outer refrigerant, a liquid level sensor for detecting a liquid level position in the storage tank, and a detection result of the liquid level sensor And a charging state management means for managing the charging state of the outer refrigerant based on the above. Here, the filling state management means may be configured to include the liquefaction mechanism and the introduction mechanism.

  The storage tank is connected to the inside of the outer heat insulating pipe through the discharge pipe, and the liquid level in the storage tank corresponds to the position of the upper end of the outer refrigerant. That is, if the height of the liquid level in the storage tank is managed, the state of filling of the outer refrigerant in the outer heat insulating pipe can be appropriately managed. Therefore, if it is a superconducting cable provided with a storage tank, a liquid level sensor, and a filling state management means, the filling state of the outer refrigerant can always be maintained in an appropriate state.

  As the superconducting cable of the present invention, the maximum pressure of the outer refrigerant in the vaporization allowable section is α (MPa), the boiling point of the outer refrigerant at α (MPa) is β (° C.), and the current capacity of the superconductor at the β (° C.) is When γ (A) is used, a form in which α (MPa) is adjusted so that the value of γ (A) satisfies a value required for a superconducting cable to be installed can be given.

  The superconducting cable is not simply maintained in the superconducting state, but needs to be operated in a state having a predetermined current capacity γ (A) required for the laid superconducting cable. Therefore, if the pressure α (MPa) of the outer refrigerant is adjusted so as to satisfy the predetermined current capacity γ (A), the current capacity (A) of the superconducting cable is prevented from falling below a predetermined value during operation of the superconducting cable. be able to. Here, the pressure α (MPa) of the outer refrigerant is used to adjust the current capacity γ (A) because the temperature of the inner refrigerant that cools the superconducting conductor is the boiling point β (° C.) of the outer refrigerant at the outer periphery of the inner refrigerant. This is because the boiling point β (° C.) of the outer refrigerant is determined by the pressure α (MPa) of the outer refrigerant. When there is a vaporization allowable section and a section (supercooling section) that is not so, the smaller current capacity in both sections is the current capacity of the entire superconducting cable. Therefore, it is preferable to set the vaporization allowable section so that the current capacity of the superconducting cable as a whole can be increased.

  As the superconducting cable of the present invention for adjusting the maximum pressure α (MPa) of the outer refrigerant in the vaporization allowable section, a form in which the α (MPa) is 0.2 or less can be mentioned.

  The above 0.2 MPa is an example of the maximum pressure α. When a high-temperature superconducting material such as Bi2223 series or RE123 series (RE: rare earth elements such as Y, Ho, Nd, Sm, Gd) is used as the superconducting conductor, the maximum use temperature is preferably about 85K. . That is, it is preferable that the upper limit of the boiling point β (° C.) of the outer refrigerant is about 85K. Here, liquid nitrogen often used as an outer refrigerant has a boiling point of about 85 K when the pressure is 0.2 MPa. For this reason, an example of the maximum pressure α (MPa) is 0.2 MPa or less.

  As the superconducting cable of the present invention, a form in which the internal member housing tube has a heat transfer structure can be exemplified.

  According to the above configuration, heat exchange can be performed between the outer refrigerant and the inner refrigerant. This configuration is particularly suitable for a superconducting cable that performs AC power transmission. In the case of a superconducting cable for AC transmission, the superconducting conductor generates heat. However, if heat exchange can be performed between the outer refrigerant and the inner refrigerant as in the above configuration, the outer refrigerant passes through the inner member storage tube from the inner refrigerant. Thus, heat can be released and the temperature rise of the inner refrigerant can be suppressed.

  As the superconducting cable of the present invention, a form in which the internal member housing pipe has a heat insulating structure can be exemplified.

  By setting it as the said structure, it can suppress effectively that the invasion heat | fever from an external environment is transmitted to an inner side refrigerant | coolant. This configuration is particularly suitable for a superconducting cable that performs DC power transmission. This is because a superconducting cable for direct current power transmission is preferably configured such that heat cannot be exchanged between the outer refrigerant and the inner refrigerant because heat to be processed is only intrusion heat from the external environment.

  As the superconducting cable of the present invention, the internal member housing tube can be biased to the vertically lower side of the outer heat insulating tube.

  Since the vaporized gas is biased vertically upward in the outer heat insulating tube, if the inner member housing tube is vertically below the outer heat insulating tube, the inner member housing tube is easily surrounded by the outer refrigerant over the entire circumference. In addition, the superconducting cable including the discharge mechanism has an effect that the vaporized gas located vertically above the outer heat insulating tube can be easily guided to the discharge mechanism.

  As the superconducting cable of the present invention, a form in which at least one of the inner refrigerant and the outer refrigerant is liquid nitrogen or liquid air can be mentioned.

  Since liquid nitrogen or liquid air is inexpensive and easily available, it is suitable for cooling the superconducting conductor.

  Moreover, the superconducting cable line of the present invention includes at least a part of the superconducting cable of the present invention described above.

  For example, when a superconducting cable line is constructed by connecting a plurality of superconducting cables, if the installation location of the cooling system is narrow and there is a section that requires simplification of the cooling system, the section may be the superconducting cable of the present invention. Of course, you may apply the superconducting cable of this invention over the full length of a superconducting cable track | line.

  According to the superconducting cable of the present invention, the time from the stop of the cooling system to the stop of power transmission can be extended.

It is a schematic block diagram of the superconducting cable track shown in Embodiment 1. (A) is a schematic cross-sectional view of the cable part of a low-temperature insulated superconducting cable, and (B) is a schematic cross-sectional view of the cable part of a room-temperature insulated superconducting cable. It is a schematic explanatory drawing of the liquefaction mechanism and introduction mechanism which are shown in Embodiment 2. It is a schematic block diagram of the superconducting cable track shown in Embodiment 3. It is a schematic block diagram of the superconducting cable track shown in Embodiment 4. It is a schematic explanatory drawing of the discharge mechanism provided with two or more by the longitudinal direction of the cable part. (A), (B) is a schematic sectional drawing of a discharge mechanism provided with a guide member. It is a schematic block diagram of the superconducting cable track shown in Embodiment 6.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, what attaches | subjects the same code | symbol in each drawing is the same thing.

<Embodiment 1>
FIG. 1 is a schematic configuration diagram of a superconducting cable line 101 of the present embodiment. The superconducting cable line 101 is composed of a single superconducting cable 1 of the present invention, and can be used for AC power transmission or DC power transmission. Note that a superconducting cable line can be constructed by connecting a plurality of superconducting cables 1 of the present invention, or a superconducting cable line can be constructed by combining the superconducting cable of the present invention and a conventional superconducting cable.

  The superconducting cable line 101 (superconducting cable 1) in this embodiment includes a cable part 90, a refrigerant replenishing mechanism 40 connected to a terminal 91 on the left side of the cable part 90, a terminal 91 on the left side of the paper, and a terminal 92 on the right side of the paper. And two discharge mechanisms 50 connected to each other. The cable portion 90 is filled with an inner refrigerant (not shown) that cools the cable inner member to a cryogenic temperature and an outer refrigerant (not shown) disposed on the outer peripheral side of the inner refrigerant in the cable portion 90. ing. Hereinafter, the configuration of the superconducting cable 1 will be described in detail.

  In describing the superconducting cable 1, first, the configuration of the cable portion 90 of the superconducting cable 1 will be described based on the cross-sectional view of FIG. A superconducting cable 1 including a cable portion 90 shown in FIG. 2A is a so-called low-temperature insulated superconducting cable. Note that the low-temperature insulated superconducting cable can be replaced with a room-temperature insulated superconducting cable. This point will be described in a modified embodiment 1-1 with reference to FIG.

≪Cable part≫
As shown in FIG. 2A, the cable portion 90 of the low-temperature insulated superconducting cable includes a cable internal member 10 including the superconducting conductor 12, and an internal member storage tube 20 in which the cable internal member 10 is stored. And an outer heat insulating tube 30 in which the inner member housing tube 20 is housed. The cable inner member 10 is preferably biased vertically downward within the inner member housing tube 20, and the inner member housing tube 20 is biased vertically downward within the outer heat insulating tube 30.

[Cable internal members]
The cable inner member 10 typically has a configuration in which a superconducting conductor 12, an electrical insulating layer 13, an outer conductor layer 14, and a protective layer 15 are sequentially provided on the former 11.

  The former 11 is a member used as a support for the superconducting conductor 12, and for example, a solid body as shown in FIG. 2A can be used. As the shape of the former 11, a pipe-like hollow body can be used in addition to the solid body. The material of the former 11 is not particularly limited. If the former 11 is simply used as a support for the superconducting conductor 12, the former 11 may be made of a non-conductive material such as a resin (for example, fiber reinforced plastic), or the current flow to the former 11 may be shunted. If it also has a function as a path, it may be made of a normal conductive metal material such as copper or aluminum.

  The superconducting conductor 12 can be formed by, for example, winding a tape-like wire rod having an oxide superconductor spirally around the outer periphery of the former 11. The tape-shaped wire may be wound in a single layer shape or may be wound in a multilayer shape. Examples of the tape-shaped wire include Bi2223 superconducting tape wire (sheath wire in which a filament made of an oxide superconductor is disposed in a stabilizing metal such as Ag-Mn or Ag), RE123 thin film wire (RE: rare earth) Elements such as Y, Ho, Nd, Sm, Gd, etc. (a laminated wire in which an oxide superconducting phase is formed on a metal substrate).

  The electrical insulating layer 13 can be formed, for example, by winding semi-synthetic paper (PPLP: registered trademark, manufactured by Sumitomo Electric Industries, Ltd.) laminated with kraft paper and a resin film such as polypropylene around the outer periphery of the superconducting conductor 12. The electrical insulating layer 13 is cooled to a cryogenic temperature together with the superconducting conductor 12 in an internal member storage tube 20 described later.

  The outer conductor layer 14 can be formed by winding a superconducting wire similar to that used for the superconducting conductor 12, for example, around the outer periphery of the electrical insulating layer 13. When the outer conductor layer 14 is composed of a superconducting wire, it can be used as an electromagnetic shield in an AC cable, and in a DC cable, it is a forward conductor layer (return conductor layer) that constitutes one of a current forward path and a return path, or neutral. Can be used as a line.

  The protective layer 15 can be formed, for example, by winding kraft paper. The protective layer 15 mechanically protects the outer conductor layer 14 and insulates it from the inner member storage tube 20.

[Internal member storage tube]
The internal member storage tube 20 is a conduit that stores the cable internal member 10 described above. The internal member storage tube 20 may have a heat transfer structure or a heat insulation structure. If the internal member storage tube 20 has a heat transfer structure, the internal member storage tube 20 may be constituted by a single tube made of stainless steel, aluminum, an alloy thereof, or the like, as shown in FIG. On the other hand, if the internal member storage tube 20 has a heat insulating structure, the internal member storage tube 20 may be constituted by a multiple structure heat insulating tube, for example, as an outer heat insulating tube 30 described later. The superconducting cable 1 that employs the internal member housing tube 20 having a heat transfer structure is suitable for AC power transmission, and the superconducting cable 1 that employs the internal member housing tube 20 having a heat insulating structure is suitable for DC power transmission.

[Outside insulation pipe]
The outer heat insulating tube 30 includes an inner tube 31 that houses the inner member housing tube 20 inside, and an outer tube 32 that houses the inner tube 31 inside. A vacuum is drawn between the inner tube 31 and the outer tube 32, thereby forming a vacuum heat insulating layer. In addition, if a heat insulating material such as a super insulation or a spacer that separates the inner tube 31 and the outer tube 32 is disposed between the inner tube 31 and the outer tube 32, the heat insulating property of the outer heat insulating tube 30 can be improved. In this embodiment, a double-structure heat insulation pipe is used as the heat insulation pipe, but a triple-structure or more heat insulation pipe may be used.

  Examples of the constituent material of the inner tube 31 and the outer tube 32 include metals such as stainless steel, aluminum, and alloys thereof. The materials of both pipes 31 and 32 may be different. Moreover, both the pipes 31 and 32 can be corrugated pipes that have been corrugated over their entire length. By doing so, the cable part 90 can be made easy to bend at the time of conveyance or laying (the same applies to the internal member storage tube 20).

≪Inner refrigerant≫
The inner refrigerant 20C is filled into the inner member storage tube 20 of the cable portion 90 described above. The inner refrigerant 20C can cool the superconducting conductor 12 of the cable inner member 10 to a cryogenic temperature and maintain the superconducting conductor 12 in a superconducting state. As the inner refrigerant 20C, liquid nitrogen (boiling point: about 77K), liquid air (boiling point: about 83K), liquid oxygen (boiling point: about 90K), liquid hydrogen (boiling point: about 20.6K), liquid helium (boiling point; About 4.2K) can be used. When the superconducting conductor provided in the cable inner member 10 is a high-temperature superconducting material such as Bi2223 series or RE123 series (RE: rare earth elements such as Y, Ho, Nd, Sm, Gd, etc.), it has a boiling point of about 85K or less. Liquid refrigerant is preferable, and liquid nitrogen is most preferable in consideration of safety, availability, insulation, and cost.

  The inner refrigerant 20C is filled in the inner member storage pipe 20 in a state of a pressure higher than the maximum pressure of the outer refrigerant 30C in the vaporization allowable section R1. Further, the inner refrigerant 20 </ b> C may be circulated from one end of the inner member storage tube 20 toward the other end. In addition, a return pipe (not shown) may be arranged in parallel with the cable portion 90, and the inner refrigerant 20C may be circulated and cooled in a closed circulation path. When the superconducting cable 1 is used for AC power transmission, the inner refrigerant 20C is preferably circulated. This is because the superconducting conductor generates heat due to the AC loss, and it is necessary to treat this heat in order to keep the superconducting conductor at a very low temperature.

≪Outside refrigerant≫
An outer refrigerant 30 </ b> C is filled in a filling portion that is a space inside the outer heat insulating tube 30 in the cable portion 90 and outside the inner member housing tube 20. The outer refrigerant 30 </ b> C can treat intrusion heat through the outer heat insulating pipe 30 to suppress the temperature rise of the inner member storage pipe 20. If the temperature rise of the internal member storage tube 20 can be suppressed, the temperature increase of the inner refrigerant 20C filled in the internal member storage tube 20 can be suppressed, and the superconducting conductor 12 can be maintained at a very low temperature.

  As the outer refrigerant 30C, a liquid refrigerant that can be used for the inner refrigerant 20C described above can be used. The same liquid refrigerant may be used for the outer refrigerant 30C and the inner refrigerant 20C, or different liquid refrigerants may be used. In the latter case, it is preferable to use a liquid refrigerant having a boiling point lower than that of the inner refrigerant 20C as the outer refrigerant 30C. Further, the outer refrigerant 30C may be solid-liquid mixed. For example, when liquid nitrogen is used as the outer refrigerant 30C, slush nitrogen may be included in the liquid nitrogen. Gasification of liquid nitrogen can be delayed by using slush nitrogen.

  The outer refrigerant 30C may be simply filled in the filling portion, or may be circulated from one end of the filling portion toward the other end. However, the outer refrigerant 30C is not circulated in the closed circulation path. That is, even if the outer refrigerant 30C flows from one end of the filling portion toward the other end, the outer refrigerant 30C flowing to the other end side remains in a liquid state and returns to one end of the filling portion via a return pipe or the like. There is nothing.

  The reason why the outer refrigerant 30C is not circulated is that a vaporization allowable section is set in the filling portion of the superconducting cable 1 of the present invention. In the superconducting cable 1 of the present invention, as shown in FIG. 1, a vaporization allowable section R1 is set over the entire length of the cable portion 90 (that is, the entire length of the outer heat insulating tube 30 shown in FIG. 2A). The vaporization allowable section R1 is a section in which intrusion heat from the external environment through the outer heat insulating pipe 30 is processed by vaporization of the outer refrigerant 30C. As long as the outer refrigerant 30C exists in the vaporization allowable section R1 to the extent that it surrounds the outer periphery of the inner member storage pipe 20, the temperature of the inner member storage pipe 20 is prevented from rising above the boiling point of the outer refrigerant 30C.

  In the superconducting cable 1 of the present embodiment, the maximum pressure of the outer refrigerant 30C in the vaporization allowable section R1 is α (MPa), the boiling point of the outer refrigerant 30C at α (MPa) is β (° C.), and β (° C.). When the current capacity of the superconducting conductor 12 in FIG. 2 (see FIG. 2A) is γ (A), α (A) so that the value of γ (A) satisfies the value required for the superconducting cable 1 to be installed. MPa) is adjusted. As shown in FIG. 1, in this embodiment, since the vaporization allowable section R1 is set over the entire length of the cable portion 90, the cable portion that is curved so as to protrude downward in the vertical direction of the cable portion 90 and vertically downward. The pressure of the outer refrigerant 30 </ b> C at the deepest portion of 90 is the maximum pressure α (MPa).

  The value of α (MPa) is, for example, 0.2 or less. This pressure of 0.2 MPa is an example of a pressure when liquid nitrogen is employed for the outer refrigerant 30C. Liquid nitrogen has a boiling point of about 85K when its pressure is 0.2 MPa. That is, in the vaporization permissible section R1 filled with the outer refrigerant 30C made of 0.2 MPa liquid nitrogen, the temperature may rise to about 85K, and the temperature of the superconductor 12 in the vaporization permissible section R1 also rises to about 85K. there is a possibility. The current capacity γ (A) of the superconducting conductor 12 tends to decrease as the temperature rises. In order for the Bi2223-based or RE123-based superconducting conductor 12 to satisfy the predetermined current capacity γ (A), the allowable temperature must be set. About 85K is preferable. Therefore, by setting the pressure α (MPa) of the outer refrigerant 30C to 0.2 or less, the outer refrigerant 30C is maintained in a liquid state and satisfies the current capacity (A) of the superconducting conductor 12 (that is, the superconducting cable 1). be able to. Under such a condition, the number of superconducting wires constituting the superconducting conductor 12 does not become excessive.

≪Refrigerant replenishment mechanism≫
In the configuration in which the intrusion heat is processed by vaporization of the outer refrigerant 30C, the outer refrigerant 30C continues to decrease. Therefore, as shown in FIG. 1, the superconducting cable line 101 (superconducting cable 1) of the present embodiment is provided with a refrigerant replenishing mechanism 40 that replenishes the outer refrigerant 30C lost due to vaporization. As the refrigerant replenishment mechanism 40, for example, a storage tank 42 for storing a liquid refrigerant 42C (which may contain a slush refrigerant), and an introduction for introducing the liquid refrigerant 42C of the storage tank 42 into the cable portion 90 as an outer refrigerant 30C. The structure provided with the pipe | tube 41 can be mentioned. It is preferable that the introduction pipe 41 and the storage tank 42 have a heat insulating structure, so that heat intrusion from the refrigerant replenishing mechanism 40 to the outer refrigerant 30C can be suppressed. The introduction of the liquid refrigerant 42C into the cable portion 90 may be performed by pressure feeding using a pump or the like, or may be performed by the weight of the liquid refrigerant 42C.

  The introduction pipe 41 of the refrigerant replenishing mechanism 40 is preferably provided with a valve or a pump. By providing these, the introduction amount of the liquid refrigerant 42C can be adjusted. It is preferable that the valves and pumps are automatically controlled by a computer or the like. The refrigerant replenishing mechanism 40 may include a refrigerator that cools the liquid refrigerant 42C. If it is the structure provided with a refrigerator, the vaporization of the liquid refrigerant in the storage tank 42 can be suppressed, and the replenishment frequency of the liquid refrigerant 42C to the storage tank 42 can be lowered.

≪Discharge mechanism≫
The discharge mechanism 50 is a mechanism that discharges the vaporized gas of the outer refrigerant 30C (see FIG. 2A) generated in the vaporization allowable section R1 from the filling unit. The discharge mechanism 50 of the present embodiment includes a discharge pipe 51 connected to the filling portion at the position of the terminal 91 (92) and a storage tank 52 connected to the discharge pipe 51, and the vaporized gas is high when discharging the vaporized gas. The property of moving to a place is used. It is preferable that the discharge pipe 51 and the storage tank 52 have a heat insulating structure, so that heat intrusion from the discharge mechanism 50 can be suppressed.

  In the storage tank 52 of the discharge mechanism 50, excess liquid refrigerant 52 </ b> C that does not fit in the outer refrigerant filling portion of the cable portion 90 is stored. Inside the storage tank 52, the liquid refrigerant 52C and the vaporized gas generated in the vaporization allowable section R1 are separated. The separated vaporized gas may be released to the external environment, or may be liquefied again and used as the outer refrigerant 30C as shown in a second embodiment described later.

≪Effect of superconducting cable line of the present invention≫
According to the superconducting cable line 101 (superconducting cable 1) described above, even if a trouble occurs in the cooling system of the inner refrigerant 20C that cools the superconducting conductor 12 of the cable inner member 10 to a cryogenic temperature, from the time of occurrence of the trouble. The time until the power transmission is stopped (the operation continuation time at the time of abnormality) can be extended longer than the conventional configuration. This is because intrusion heat from the external environment can be processed by vaporization of the outer refrigerant 30C, so that the temperature of the inner refrigerant 20C remains at the outer refrigerant 30C while the outer refrigerant 30C remains to some extent in the filling portion of the cable portion 90. It is because it is suppressed that it raises more than the boiling point of.

  The effect of extending the power transmission continuation time at the time of abnormality can be obtained in both AC transmission and DC transmission. This extension effect can be improved by limiting the configuration of the superconducting cable line 101. Specifically, in the case of AC power transmission, the internal member storage tube 20 can be made to have a heat transfer structure, and the inner refrigerant 20C can be circulated and cooled. Moreover, in the case of direct current power transmission, it is mentioned that the internal member storage tube 20 has a heat insulating structure.

<Modified Embodiment 1-1>
The low-temperature insulated superconducting cable described in the first embodiment can be replaced with a room-temperature insulated superconducting cable. As the room temperature insulation type superconducting cable, for example, a superconducting cable including a cable portion 90 ′ shown in the cross-sectional view of FIG. 2B can be used. This replacement can be similarly performed in Embodiments 2 to 6 described later.

≪Room-temperature insulated superconducting cable≫
The cable portion 90 ′ of the room temperature insulation type superconducting cable shown in FIG. 2B is similar to the cable portion 90 of the low temperature insulation type superconducting cable shown in FIG. A tube 20 ′ and an outer heat insulating tube 30 ′ are provided. The main difference between the two types is the configuration of the cable inner member and the configuration of the outer heat insulating tube. Hereinafter, the difference between the two types will be mainly described.

[Cable internal members]
The cable internal member 10 ′ includes the superconducting conductor 12 and the protective layer 15 on the outer periphery of the former 11, but does not have an equivalent to the electrical insulating layer 13 in the cable internal member 10 of FIG. The superconducting conductor 12 is connected to the inner member housing tube 20 ′ at the terminal or joint portion, and the superconducting conductor 12 and the inner member housing tube 20 ′ are at the same potential. Therefore, as shown in the configuration of the outer heat insulating tube 30 ′, which will be described later, in the room temperature insulation type superconducting cable, an electrical insulating layer 33 is provided on the outer periphery of the outer heat insulating tube 30 ′. As the protective layer 15, craft tape or the like can be used.

[Outside insulation pipe]
The outer heat insulating tube 30 ′ includes an electric insulating layer 33 on the outer periphery of the outer tube 32 in addition to the inner tube 31 and the outer tube 32. The electrical insulating layer 33 has a desired withstand voltage characteristic and is used in a normal temperature environment. The electrical insulating layer 33 can be made of a material having a proven record in normal conducting cables and having excellent electrical insulation strength, typically, crosslinked polyethylene (XLPE) used for CV cables. In the case of an insulating resin such as cross-linked polyethylene, the electrical insulating layer 33 can be easily formed simply by extruding the insulating resin to the outer periphery of the outer tube 32.

<Embodiment 2>
In the second embodiment, a configuration including a liquefaction mechanism that re-liquefies the vaporized gas separated by the discharge mechanism described in the first embodiment and an introduction mechanism that introduces the re-liquefied refrigerant into the outer heat insulating pipe as an outer refrigerant again will be described. To do. The liquefaction mechanism and the introduction mechanism can be constructed by using, for example, a discharge mechanism and a refrigerant replenishment mechanism. An example of the construction will be described with reference to FIG. FIG. 3 shows only the vicinity of the terminal 91 where the refrigerant replenishment mechanism 40 and the discharge mechanism 50 are provided.

  The liquefaction mechanism 60 includes, for example, a communication pipe 61 extending from a gas phase part of the storage tank 52 of the discharge mechanism 50 to a gas phase part (or a liquid phase part) of the storage tank 42 of the refrigerant replenishment mechanism 40, The structure provided with the liquefier 62 provided in the middle can be mentioned. According to this liquefaction mechanism 60, the vaporized gas separated in the storage tank 52 of the discharge mechanism 50 can be liquefied by the liquefier 62 and replenished to the storage tank 42 of the refrigerant replenishment mechanism 40 as the liquefied liquid refrigerant 42C. .

  On the other hand, the introduction mechanism of the present embodiment can use the refrigerant replenishment mechanism 40 as it is. Of course, an introduction mechanism may be provided separately from the refrigerant replenishment mechanism 40.

  According to the configuration described above, the replenishment frequency of the liquid refrigerant 42C can be reduced. This is because the vaporized gas separated by the discharge mechanism 50 can be reused as the liquid refrigerant 42C.

  In the present embodiment, a configuration for managing the charging state of the outer refrigerant 30C (see FIG. 2A) is further provided. As its configuration, the storage tank 52 of the discharge mechanism 50, the liquid level sensor 70 for detecting the liquid level position in the storage tank 52, and the filling state of the outer refrigerant 30C are managed based on the detection result of the liquid level sensor 70. And a filling state management means. The storage tank 52 is connected to the inside of the outer heat insulating tube 30, and the liquid level of the liquid refrigerant 52C in the storage tank 52 corresponds to the position of the upper end of the outer refrigerant 30C. In other words, if the height of the liquid level in the storage tank 52 is managed, it is possible to appropriately manage the filling state of the outer refrigerant 30C in the outer heat insulating pipe 30.

  As the liquid level sensor 70, a known liquid level sensor such as a float type, an optical type, or an ultrasonic type can be used. On the other hand, as the filling state management means, a computer (not shown) that can be used in the introduction mechanism can be used. For example, the computer controls the liquefier 62 of the liquefaction mechanism 60 to adjust the amount of liquid refrigerant to be liquefied, or to control the output of the pump if the refrigerant replenishment mechanism 40 includes a pump. Can be mentioned.

<Embodiment 3>
In the third embodiment, a superconducting cable line 102 having an inclined structure having a difference in height on one end side (terminal 91 side) and the other end side (terminal 92 side) in the longitudinal direction of the superconducting cable line 102 will be described with reference to FIG. .

  In the superconducting cable line 102 of FIG. 4, the height of the cable portion 90 gradually increases from the terminal 91 side toward the terminal 92 side. Further, a vaporization allowable section R1 is set over the entire length of the cable portion 90. In this configuration, the vaporized gas generated in the vaporization allowable section R1 of the cable portion 90 gathers at the terminal 92 disposed on the high place side. Therefore, in this embodiment, the discharge mechanism 50 is provided only on the terminal 92 side.

  According to the configuration described above, management of the superconducting cable line 102 can be facilitated. This is because the refrigerant replenishing mechanism 40 and the discharging mechanism 50 having a high maintenance frequency are arranged on the terminal 92 side.

<Embodiment 4>
In the fourth embodiment, a superconducting cable line 103 in which the height difference between the terminal 91 and the terminal 92 is larger than that of the superconducting cable line 102 of the third embodiment will be described with reference to FIG.

  If the height difference between the terminal 91 and the terminal 92 is large as in the superconducting cable line 103 shown in FIG. 4, the pressure of the outer refrigerant 30 </ b> C in the vicinity of the terminal 91 on the low side increases. As the pressure of the outer refrigerant 30C increases, the boiling point of the outer refrigerant 30C also increases, so that the temperature of the internal member storage tube 20 (that is, the superconducting conductor 12 in the internal member storage tube 20) is adjusted to an appropriate temperature by the outer refrigerant 30C. There is a risk that it cannot be maintained (see also FIG. 2). Therefore, in the present embodiment, the refrigerant replenishing mechanism 40 including the pump 43 that pumps the liquid refrigerant is connected to the terminal 91 on the low side, and the outer refrigerant 30C is connected to a portion of the cable portion 90 having a predetermined length from the terminal 91. A supercooling section R2 that flows at a predetermined flow rate was used. In the supercooling section R2, since the predetermined outer refrigerant 30C is supplied, the temperature rise of the outer refrigerant 30C is suppressed. On the other hand, the part excluding the supercooling section R2 in the cable portion 90 is set as the vaporization allowable section R1 as in the first and second embodiments, and the intrusion heat is processed by the evaporation of the outer refrigerant 30C.

  The setting of the vaporization allowable section R1 and the supercooling section R2 is determined by the pressure of the outer refrigerant 30C. Specifically, the maximum pressure in the vaporization allowable section R1 is determined so that α (MPa) is a predetermined value or less. An example of the predetermined value is 0.2 MPa when liquid nitrogen is used as the outer refrigerant 30C. This is because the boiling point of 0.2 MPa of liquid nitrogen is about 85K, and the current capacity of a high-temperature superconducting wire such as Bi2223 at 85K is likely to satisfy a value required for a general superconducting cable.

  According to the configuration described above, even in a superconducting cable line having a height difference, it is possible to extend the time from the occurrence of an abnormality in the cooling system to the stop of operation of the line.

<Embodiment 5>
This embodiment demonstrates the structure which provided the some discharge mechanism 50 in the superconducting cable track | line (superconducting cable) in the said Embodiment 1-4 based on FIG. Of course, the structure provided with the several discharge mechanism 50 can also be applied to Embodiment 6 mentioned later.

  As shown in FIG. 6, the present embodiment includes a plurality of discharge mechanisms 50 connected to the outer heat insulating tube 30 of the cable portion 90. By providing the several discharge mechanism 50, the vaporization gas generate | occur | produced in the filling part of the outer side refrigerant | coolant in the outer side heat insulation pipe | tube 30 can be discharged | emitted rapidly, and the expansion of the gas pool in a filling part can be suppressed. The configuration in which the plurality of discharging mechanisms 50 are provided is particularly effective when the cable portion 90 meanders up and down. In that case, for example, if each discharge mechanism 50 is provided in a portion that is curved so that the cable portion 90 protrudes vertically upward, the expansion of the gas reservoir in that portion can be effectively suppressed.

  In the present embodiment, the vaporized gas separated in the storage tank 52 of each discharge mechanism 50 is collected in one place by the collecting pipe 55 connected to the gas phase portion of each storage tank 52. The collected vaporized gas is preferably reliquefied by the liquefaction mechanism 60 described with reference to FIG. 3 and reused as the outer refrigerant 30C, for example.

  Further, each discharge mechanism 50 may include a guide member that guides the vaporized gas to the discharge pipe 51. For example, guide members 53 and 54 illustrated in FIGS. 7A and 7B can be used. In addition, the solid line arrow in a figure shows the flow of the outer refrigerant | coolant 30C, and a dotted line arrow shows the flow of vaporization gas.

  First, the guide member 53 shown in FIG. 7A protrudes from the inner peripheral surface on the vertically upper side in the inner tube 31 of the outer heat insulating tube 30 toward the vertically lower side. Further, the position of the guide member 53 in the longitudinal direction of the superconducting cable 1 is set on the higher side (right side of the drawing) than the discharge pipe 51 of the discharge mechanism 50. Therefore, the vaporized gas that moves to the high place along the inner peripheral surface on the vertically upper side of the inner pipe 31 is blocked by the guide member 53 and guided to the discharge pipe 51.

  On the other hand, the guide member 54 shown in FIG. 7B protrudes from the inner peripheral surface on the vertically lower side in the inner tube 31 of the outer heat insulating tube 30 toward the vertically upper side. The internal member storage tube 20 is provided through the guide member 54, and therefore the guide member 54 also serves as a positioning member for the internal member storage tube 20 in the outer heat insulating tube 30. Further, the position of the guide member 54 in the longitudinal direction of the superconducting cable 1 is set within the opening range of the discharge pipe 51. With this configuration, the flow of the outer refrigerant 30C and the flow of the vaporized gas are bent vertically upward at the position of the guide member 54. Therefore, the vaporized gas guided vertically upward at the position of the guide member 54 is discharged as it is from the discharge pipe 51 positioned vertically above the guide member 54.

<Embodiment 6>
In the present embodiment, a superconducting cable line 104 including two superconducting cables 1A and 1B will be described based on the schematic configuration diagram of FIG. In FIG. 8, the two superconducting cables 1A and 1B are arranged in parallel vertically, but they may be arranged side by side at the same height.

  Both the superconducting cables 1A and 1B included in the superconducting cable line 104 include a vaporization allowable section R1 and a supercooling section R2. The refrigerant replenishing mechanism 40A of the superconducting cable 1A is connected to the terminal 91 on the left side of the drawing, and the discharging mechanism 50A of the superconducting cable 1A is connected to the terminal 92 on the right side of the drawing. On the other hand, the refrigerant replenishing mechanism 40B of the superconducting cable 1B is connected to the terminal 93 on the right side of the drawing, and the discharging mechanism 50B of the superconducting cable 1B is connected to the terminal 94 on the left side of the drawing. Further, the discharging mechanism 50A of the superconducting cable 1A and the refrigerant replenishing mechanism 40B of the superconducting cable 1B are connected via a liquefying mechanism 60A including a liquefier 62. Further, the discharging mechanism 50B of the superconducting cable 1B and the refrigerant replenishing mechanism 40A of the superconducting cable 1A are connected via a liquefying mechanism 60B including a liquefier 62.

  When operating the superconducting cable line 104 having the above-described configuration, the liquid refrigerant 42C sent from the storage tank 42 of the refrigerant replenishing mechanism 40A to the cable portion of the superconducting cable 1A via the terminal 91 is discharged from the terminal 92 to the discharging mechanism 50A. The storage tank 52 is discharged. Accordingly, the vaporized gas generated in the cable portion of the superconducting cable 1A is also discharged into the storage tank of the discharge mechanism 50A. The vaporized gas is reliquefied by the liquefaction mechanism 60A and introduced into the storage tank 42 of the refrigerant replenishment mechanism 40B. Similarly, in the superconducting cable 1B, the vaporized portion of the liquid refrigerant 42C sent from the refrigerant replenishing mechanism 40B to the cable portion of the superconducting cable 1B via the terminal 93 is reliquefied by the liquefying mechanism 60B, and the refrigerant replenishing mechanism. Introduced into 40A. Thus, since the liquid refrigerant 42C in the superconducting cable line 104 is reused by repeated vaporization and liquefaction, the frequency of replenishing the liquid refrigerant 42C in the superconducting cable line 104 can be dramatically reduced.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the gist of the present invention. For example, the superconducting cable described in the embodiment may be replaced with a superconducting cable including a plurality of cable internal members. In that case, each cable internal member may be disposed inside the internal member storage tube, and these internal member storage tubes may be collectively disposed inside the outer heat insulating tube.

  The superconducting cable of the present invention and the superconducting cable line using the superconducting cable of the present invention can be used for a power transmission path in a factory, for example.

101-104 Superconducting cable line 1, 1A, 1B Superconducting cable 90, 90 'Cable part 10, 10' Cable inner member 11 Former 12 Superconducting conductor 13 Electrical insulation layer 14 Outer conductor layer 15 Protective layer 20, 20 'Inner member housing tube 30, 30 'outer heat insulating pipe 31 inner pipe 32 outer pipe 33 electric insulation layer 20C inner refrigerant 30C outer refrigerant R1 vaporization allowable section R2 supercooling section 40, 40A, 40B refrigerant replenishment mechanism 41 introduction pipe 42 storage tank 43 pump 42C liquid refrigerant 50, 50A, 50B Discharge mechanism 51 Discharge pipe 52 Storage tank 53, 54 Guide member 55 Collecting pipe 52C Liquid refrigerant 60, 60A, 60B Liquefaction mechanism 61 Communication pipe 62 Liquefaction machine 70 Liquid level sensors 91-94 Terminal

Claims (21)

A superconducting cable comprising a cable inner member having a superconducting conductor,
A cable portion including the cable internal member, an internal member storage pipe in which the cable internal member is stored, and an outer heat insulating pipe in which the internal member storage pipe is stored;
An inner refrigerant that is filled in the inner member storage pipe and cools the superconducting conductor provided in the cable inner member to a cryogenic temperature;
An outer refrigerant that is filled inside the outer heat insulating tube and outside the inner member housing tube and suppresses a temperature rise of the inner member housing tube,
At least a part of the outer heat insulating pipe in the longitudinal direction of the outer refrigerant filling portion inside the outer heat insulating pipe is a vaporization permissible section that allows vaporization of the outer refrigerant, and the outer heat insulating pipe is A superconducting cable that suppresses an increase in the temperature of the internal member storage tube by processing intrusion heat from the external environment via the vaporization of the external refrigerant in the external heat insulation tube.   The superconducting cable according to claim 1, further comprising a refrigerant replenishing mechanism that replenishes the outer refrigerant lost due to vaporization.   The superconducting cable according to claim 1, wherein a vaporization allowable section is formed over the entire length of the outer heat insulating pipe. The outer refrigerant is pressurized and supplied by the refrigerant replenishment mechanism,
The superconducting cable according to claim 2, wherein a section excluding the vaporization-permitted section in the outer refrigerant filling portion is a supercooling section in which the outer refrigerant is in a supercooled state.   The superconducting cable according to any one of claims 1 to 4, wherein the inner refrigerant is pressurized and filled without being circulated.   The superconducting cable according to claim 1, wherein the inner refrigerant is circulated.   The superconducting cable according to any one of claims 1 to 6, which is used for direct current power transmission.   The superconducting cable according to claim 1, which is used for AC power transmission.   The superconducting cable according to any one of claims 1 to 8, further comprising a discharge mechanism having a discharge pipe for discharging the vaporized gas of the outer refrigerant from the vaporization allowable section.   The superconducting cable according to claim 9, wherein the discharging mechanism is provided at a high-side terminal of the cable portion.   The superconducting cable according to claim 9 or 10, wherein a plurality of the discharging mechanisms are provided along a longitudinal direction of the cable portion.   The superconducting cable according to any one of claims 9 to 11, wherein the discharge mechanism includes a guide member that guides the vaporized gas to the discharge pipe. further,
A liquefaction mechanism for reliquefying the vaporized gas;
An introduction mechanism for introducing the reliquefied refrigerant into the outer heat insulating pipe again as the outer refrigerant;
A superconducting cable according to any one of claims 9 to 12. A storage tank connected to the discharge pipe and storing the outer refrigerant;
A liquid level sensor for detecting the liquid level position in the storage tank;
A charging state management means for managing the charging state of the outer refrigerant based on the detection result of the liquid level sensor;
A superconducting cable according to any one of claims 9 to 13. The maximum pressure of the outer refrigerant in the vaporization allowable section is α (MPa), the boiling point of the outer refrigerant at α (MPa) is β (° C.), and the current capacity of the superconducting conductor at β (° C.) is γ (A )
The superconducting cable according to claim 1, wherein the α (MPa) is adjusted so that the value of γ (A) satisfies a value required for a superconducting cable to be laid.   The superconducting cable according to claim 15, wherein the α (MPa) is 0.2 or less.   The superconducting cable according to any one of claims 1 to 16, wherein the inner member storage tube has a heat transfer structure.   The superconducting cable according to any one of claims 1 to 16, wherein the inner member storage pipe has a heat insulating structure.   The superconducting cable according to any one of claims 1 to 18, wherein the inner member housing pipe is biased to a vertically lower side of the outer heat insulating pipe.   The superconducting cable according to any one of claims 1 to 19, wherein at least one of the inner refrigerant and the outer refrigerant is liquid nitrogen or liquid air.   A superconducting cable line comprising at least a part of the superconducting cable according to claim 1.

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