JP2013178958A - Superconductive cable system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive cable system which can be utilized as a superconductive cable line in normal time, and of which the superconductive cable line can be utilized as a normal conductive cable line in loss of a cooling function.SOLUTION: A superconductive cable system includes: a normal temperature insulating type superconductive cable 100; and a cooling mechanism 200 of coolant 20, and has terminal conductor parts to be connected with normal conductive power equipment via a current lead on both ends of the superconductive cable 100. Both terminal conductor parts include: first current leads 31 which connect a conductor part 10 with power equipment; second current leads 32 which connect an external normal conductive member 16 with the power equipment; and interception means 33a, 33b for intercepting connection between the conductor part 10, the external normal conductive member 16 and the power equipment. One interception means 33a has: first interception means 34 for intercepting connection on the side of the conductor 10; and second interception means 35 for intercepting connection on the side of the external normal conductive member 16.

Description

  The present invention relates to a superconducting cable system that constitutes a power transmission line using a room-temperature insulated superconducting cable. In particular, the present invention relates to a superconducting cable system that is normally used as a superconducting cable line and can be used as a normal conducting cable line when a cooling function is lost when the cooling mechanism of the room temperature insulated superconducting cable cannot operate normally.

  In recent years, it has been studied to connect a superconducting cable to an actual power transmission system. A superconducting cable generally has a structure in which a conductor portion having a superconducting conductor layer formed by winding a superconducting wire around the former is housed in a heat insulating tube. In such a superconducting cable, there are the following two configurations for electrically insulating the superconducting conductor layer from the outside. The first configuration is a low-temperature insulating configuration in which a main electrical insulation layer is formed outside the superconducting conductor layer, and the main electrical insulation layer is also cooled by a refrigerant together with the superconducting conductor layer (for example, Patent Document 1). (See FIG. 1). The second configuration is a room temperature insulation type configuration in which a main electrical insulation layer is formed outside the heat insulating tube and the main electrical insulation layer is not cooled by the refrigerant (see, for example, paragraph 0003 of Patent Document 2). The heat insulation pipe is usually a vacuum heat insulation pipe having a double pipe structure having an inner pipe and an outer pipe, and the heat insulation space between the inner pipe and the outer pipe is evacuated. The main electrical insulation layer is an electrical insulation layer to which the rated voltage of the cable line is applied and has an insulation strength necessary for insulation against the voltage.

  Moreover, when constructing a power transmission line using such a superconducting cable, terminals for connecting to a normal conducting device (eg, circuit breaker) are provided at both ends of the superconducting cable via current leads (for example, , See Patent Document 3).

JP 2011-065879 A Japanese Patent Laid-Open No. 08-064041 JP 2006-196628 A

In any of the above-described superconducting cables, the refrigerant is cooled and circulated by a cooling mechanism including a refrigerator and a refrigerant circulation mechanism, and the superconducting conductor layer is cooled to a cryogenic temperature by the refrigerant to be in a superconducting state. maintain. Therefore, if the cooling mechanism of this refrigerant does not operate normally due to unforeseen circumstances such as natural disasters, an alarm will be issued if it is determined that it is difficult to maintain the superconducting conductor layer in the superconducting state in the transmission system control system. At the same time, the superconducting cable line is cut off from the power transmission system. Of course, power transmission by another route is attempted, but power transmission stops when it is difficult to secure another route due to a natural disaster or the like. At that time, the normal procedure from the stoppage of power transmission to the restoration of the superconducting cable line is as follows.
(1) The circuit breaker is operated by the protection device, the superconducting cable line is interrupted, and power transmission on the line is stopped.
(2) The cause of the operation of the protective device and the state of occurrence of the abnormality are confirmed, and “whether re-transmission on the superconducting cable line is possible” is determined.
(3) When power can be transmitted through another route or a backup line, while confirming the abnormality of the superconducting cable line while continuing the power transmission, the superconducting cable line is promptly repaired and restored as necessary.

  On the other hand, if the standby line becomes unusable due to a natural disaster, etc., even if the cooling mechanism of the refrigerant does not operate normally, the entire superconducting cable line including the terminals and joints is not damaged. It would be convenient if the part could be used as an emergency power transmission line. In particular, when urgent power transmission is required for disaster recovery or the like, if power can be transmitted even with a capacity lower than the original power transmission capacity of the superconducting cable, it may be effective as valuable power.

  The present invention has been made in view of the above circumstances, and one of its purposes is that it can be used as a superconducting cable line during normal times, and that this superconducting cable line can be used as a normal conducting cable line when the cooling function is lost. The object is to provide a superconducting cable system capable of satisfying the requirements.

  The present inventors examined using a superconducting cable as a normal conducting cable when the superconducting conductor layer cannot be maintained in a superconducting state and the superconducting cable body is not damaged, such as a wound. In general, a superconducting cable includes, in addition to a superconducting conductor layer, an internal normal conducting member for shunting an accident current (eg, a short circuit current) in a conductor portion. Specific examples of such an internal normal conductive member include a former formed by twisting copper wires and a normal conductive conductor constituting a part of the superconductive wire. Considering the use of this internal normal conductive member as a main power transmission conductor when the cooling function is lost, it is difficult to ignore the effect of heat generation simply by transmitting power to this internal normal conductive member. And gained knowledge. Usually, the superconducting conductor layer and the internal normal conducting member are electrically connected and housed in the same heat insulating tube, so these conductors generate heat by power transmission, but the heat is dissipated outside the heat insulating tube. Because it is very difficult to do. And, due to the temperature rise accompanying this heat generation, there is a possibility that other components such as the superconducting conductor layer may be damaged. Therefore, the conductor member cannot be continuously used as a power transmission conductor. Based on the above knowledge, the present invention is configured to arrange a normal conductive member on the outside of a heat insulating tube and to enable power transmission using only this normal conductive member, and has the following configuration.

  The superconducting cable system according to the present invention includes a superconducting cable provided at both ends of the superconducting cable and having a terminal conductor for connecting to a normal conducting power device via a current lead, and a cooling mechanism for the refrigerant. It is. The superconducting cable used in this superconducting cable system is provided with a conductor part having a superconducting conductor layer, a heat insulating pipe that houses the conductor part and through which a refrigerant that cools the superconducting conductor layer flows, and outside the heat insulating pipe. A room temperature insulated superconducting cable comprising a main electrical insulating layer and an external normal conducting member formed between the heat insulating tube and the main electrical insulating layer. Both terminal conductor portions include a first current lead that connects the conductor portion and the power device, a second current lead that connects the external normal conductive member and the power device, a conductor portion, and an external normal conductive member. A blocking means for blocking the connection between the member and the power device is provided. The blocking means in at least one of the terminal conductor portions includes a first blocking means for blocking the connection on the conductor portion side, and a second blocking means for blocking the connection on the external normal conducting member side.

  According to this configuration, the superconducting cable can be used for power transmission as a superconducting cable line during normal times, and the superconducting cable can be used for power transmission as a normal conducting cable line when the cooling function is lost. Specifically, in normal times, in each blocking means of both terminal conductor portions, the conductor portion side and the external normal conducting member side are connected, and the conductor portion (superconducting conductor layer) is used as the main power transmission conductor. . When the cooling function is lost, one of the shut-off means sets the conductor side to the shut-off state by the first shut-off means to stop power transmission to the conductor part, and at each shut-off means of both terminal conductors, external normal conducting The member side is in a connected state, and the external normal conducting member is used as a main power transmission conductor. That is, since at least one of the blocking means has the first blocking means and the second blocking means, it is possible to switch between power transmission by the conductor part including the external normal conducting member and power transmission only by the external normal conducting member. . Therefore, based on the state of the superconducting cable, power transmission by the external normal conductive member can be performed in a state where power transmission by the conductor portion is stopped. In addition, in each blocking means of both terminal conductors, the superconducting cable is disconnected from the power transmission system on the superconducting cable system side separately from the system control system side by putting the conductor part side and the external normal conducting member side into a blocking state. It is possible.

  Here, since the external normal conducting member is provided outside the heat insulating tube, power can be transmitted within the allowable temperature range even if heat is generated by power transmission, as in the existing normal conducting cable. For this reason, even if an unexpected situation such as a natural disaster occurs, the cooling mechanism of the refrigerant does not operate normally, the superconducting conductor layer cannot be maintained in a superconducting state, and power cannot be transmitted by the conductor part. It can be used as an emergency power transmission line. Further, by stopping the power transmission by the conductor until the cooling mechanism is restored, an excessive temperature rise of the superconducting conductor layer can be avoided, and the safety is high. Furthermore, since the temperature rise in the heat insulation pipe can be suppressed for a short time by stopping the power transmission of the conductor portion, the superconducting cable line can be quickly restored after the cooling mechanism is restored.

  The external normal conductive member is made of a normal conductive material such as a metal such as copper, aluminum, silver, or an alloy thereof. In addition, the external normal conducting member can function as a shunt path for an accident current (eg, short-circuit current, etc.) during normal use as a superconducting cable, similarly to the conventional internal normal conducting member.

  Each interruption | blocking means of both the terminal conductor parts can interrupt | block the connection between a conductor part and an external normal conductive member, and a normal conductive power apparatus. Moreover, at least one interruption | blocking means has a 1st interruption | blocking means and a 2nd interruption | blocking means, and can interrupt | block separately the connection by the side of a conductor part, and the connection by the side of an external normal conducting member. For example, in the case where the first current lead and the second current lead are combined and connected to the power device, the interrupting means is configured by arranging a switch in the middle of the integrated current lead. realizable. In addition to the switch, it may be realized by detachably placing the bond line in the middle of the integrated current lead. In this case, it is possible to connect / cut off by attaching / detaching the bond line. . In this way, when the shut-off means is configured by arranging a switch or the like in the middle of the integrated current lead, the conductor portion side and the external normal conducting member side can be shut off with one switch or the like. it can.

  The first cutoff means can put the conductor portion side in a cutoff state, and can be realized by, for example, providing a switch in the middle of the first current lead or detachably attaching a bond wire. In addition, the second blocking means can put the external normal conducting member side into a blocking state, and like the first means, a switch mechanism is provided in the middle of the second current lead, or a bond wire is detachably attached. It can be realized by doing.

  Both of the blocking means may have a first blocking means and a second blocking means, respectively, but if one blocking means has the first blocking means and the second blocking means, the first blocking means The conductor part side is interrupted by the means, and the power transmission to the conductor part can be stopped.

  As one form of the superconducting cable system of the present invention, when the conductor part side is blocked by the first blocking means in one blocking means, the conductor part side is connected in the other blocking means. It is done.

  According to this configuration, when the power is transmitted by the external normal conducting member in the state where the conductor portion side is interrupted by the first interrupting means of one of the interrupting means and the power transmission by the conductor portion is stopped, By making the conductor part side into a connected state, it can be avoided that the conductor part becomes a floating electrode. Therefore, it is possible to prevent a potential difference between the conductor portion and the external normal conducting member from damaging the main electrical insulating layer such as dielectric breakdown.

  By the way, when it takes a long time for the cooling mechanism of the refrigerant to return, or when increasing the power transmission capacity when the cooling function is lost to be used as a normal conducting cable line, it is housed in a heat insulating tube for stable power transmission. It is required to use the existing conductor part (internal normal conducting member) as a power transmission conductor. Therefore, it is preferable to have the following configuration so as to enable heat dissipation of the conductor portion in the heat insulating tube.

  As one form of the superconducting cable system of the present invention, the heat insulating tube of the superconducting cable is a vacuum heat insulating tube having a heat insulating space, the cooling mechanism is inoperable, and the superconducting conductor layer can not be maintained in the superconducting state when the cooling function is lost. It may be provided with a filling means attaching portion for attaching a filling means for filling a heat conductive material in at least the heat insulating space of the vacuum heat insulating tube.

  According to this configuration, the filling means attaching portion is provided, and the filling means is attached to the filling means attaching portion so that the heat conduction material is filled into the heat insulating space of the vacuum heat insulating tube by the filling means, and the heat insulating performance of the heat insulating pipe is obtained. The vacuum insulation tube can be used as a heat transfer tube. Therefore, when the cooling function used as the normal conducting cable line is lost, the heat generated in the conductor can be radiated through the heat transfer tube even if the conductor is used as the power transmission conductor. Therefore, it can suppress that a conductor part exceeds temperature exceeding allowable temperature, and can raise the power transmission capacity at the time of normal conductive cable operation. Moreover, until the heat insulation performance of the vacuum heat insulation pipe is surely lowered, the power transmission by the conductor part is stopped and the safety is ensured by putting the conductor part side in a cut-off state by the first cut-off means. Can do. For example, if the heat insulation performance of the heat insulation pipe is drastically reduced while the refrigerant in the heat insulation pipe is at a low temperature to some extent, the temperature difference between the inside and outside of the heat insulation pipe is large, and a room temperature member that is close to the heat insulation pipe or the heat insulation pipe due to a sudden temperature change. There is a risk of damage such as damage.

  When the cooling function is lost, this filling means may be attached to the filling means attaching part afterwards when the conductor part is used as a power transmission conductor, and is attached to the filling means attaching part in advance from the beginning of the construction of the superconducting cable system. It may be done. Part of the constituent members constituting the filling means may be attached in advance to the filling means attachment portion, and when the conductor portion is used as a power transmission conductor, the remaining portion of the constituent member may be attached. The heat insulating space of the vacuum heat insulating tube is a space between the inner tube and the outer tube in the vacuum heat insulating tube having a double tube structure.

  In the said form provided with a filling means, a filling means is provided with the gas supply source which accommodates the gas used as a heat conductive material, and the 1st valve | bulb which supplies and stops gas to this heat insulation space from this gas supply source. It is done.

  According to this configuration, by operating the first valve, when the cooling function is lost, the heat insulating material is supplied to the heat insulating space of the vacuum heat insulating tube and filled with the gas, thereby reducing the heat insulating performance of the heat insulating tube. it can. As a result, the normal vacuum heat insulating tube can be used as a heat transfer tube when the cooling function is lost, and heat generated by the conductor can be radiated.

  The said form provided with a 1st valve | bulb is further equipped with the vacuum pump which evacuates the said heat insulation space, and a 1st valve is an on-off valve which selectively connects a gas supply source and a vacuum pump with respect to a heat insulation space. Can be mentioned.

  According to this structure, the heat insulation space of a vacuum heat insulation pipe | tube is connected with a gas supply source by operation | movement of an on-off valve. Then, by filling the heat-insulating space with a gas to be in a non-vacuum state, the normal superconducting cable can be used as a normal conducting cable in the power transmission line when the cooling function is lost. On the other hand, after the cooling mechanism is restored so that the superconducting conductor layer can be maintained in the superconducting state, the heat insulating space of the vacuum heat insulating tube is communicated with the vacuum pump by the operation of the opening / closing valve. Then, by evacuating the heat insulation space with this vacuum pump, the superconducting cable used as the normal conducting cable line when the cooling function is lost can be used again as the superconducting cable line. In addition, during the time when the heat insulation space is evacuated to a predetermined degree of vacuum with the vacuum pump, that is, until the transition from the normal conducting cable operation to the superconducting cable operation, the conductor section side is cut off by the first blocking means. By doing so, it is possible to stop power transmission by the conductor portion and ensure safety.

  Here, the gas supply source and the vacuum pump connected to the heat insulation pipe via the first valve are at the ground potential, while the heat insulation pipe is usually at a high potential when the superconducting cable is used for the power transmission line. Therefore, when a gas supply source or a vacuum pump is directly connected to a heat insulation pipe, there is a problem that it cannot be operated as a power transmission line. In that case, an insulation joint having a predetermined dielectric strength between the heat insulation pipe and the gas supply source or the vacuum pump It is necessary to provide.

  The said form provided with a filling means WHEREIN: It is mentioned that a filling means is provided with a liquid supply source, a supply pipe, a discharge pipe, a 2nd valve | bulb, and a pumping means. A liquid supply source stores the liquid used as the said heat conductive material. The supply pipe supplies liquid from the liquid supply source to the heat insulation space. The discharge pipe discharges the liquid from the heat insulating space. The second valve communicates and blocks each of the supply pipe and the discharge pipe. The pressure feeding means circulates the liquid using the supply pipe, the heat insulating space, and the discharge pipe as a flow path.

  According to this configuration, when the cooling function is lost, the heat insulating performance of the heat insulating tube can be lowered by supplying the liquid serving as the heat conducting material to the heat insulating space of the vacuum heat insulating tube and filling it. Thereby, a vacuum heat insulation pipe | tube can be used as a heat exchanger tube, and the heat_generation | fever of a conductor part can be radiated. Moreover, the liquid supplied to the heat insulation space is pumped (circulated), and the heat insulation pipe (heat transfer pipe) is cooled by this liquid, thereby effectively suppressing the temperature rise caused by the heat generation of the conductor part during normal conductive cable operation. You can also

  In the above-described form including the filling means, the filling means includes a communication pipe that communicates the refrigerant flow path in the vacuum heat insulation pipe and the heat insulation space of the vacuum heat insulation pipe, and a third valve that communicates and blocks the communication pipe. It is done.

  According to this configuration, when the cooling function is lost, the refrigerant in the vacuum heat insulation pipe is vaporized by intrusion heat, and the vaporized refrigerant is introduced into the heat insulation space of the vacuum heat insulation pipe through the communication pipe by the operation of the third valve. Thus, the heat insulating performance of the heat insulating pipe can be lowered. Thereby, a vacuum heat insulation pipe | tube can be used as a heat exchanger tube, and the heat_generation | fever of a conductor part can be radiated.

  In the above embodiment comprising the communication pipe and the third valve, a pressure release valve for releasing the pressure of the refrigerant vaporized when the cooling function is lost in the middle of the communication pipe, and a heat exchanging unit for increasing the temperature of the vaporized refrigerant And at least one of them.

  According to this configuration, by providing the pressure release valve, it is possible to mitigate a rapid pressure increase in the communication pipe when the refrigerant is vaporized. In addition, by providing a heat exchange part, it is possible to prevent the vaporized refrigerant from being introduced into the heat insulation space of the vacuum heat insulation pipe at an excessively low temperature, and a member at room temperature adjacent to the heat insulation pipe is unnecessarily cooled. It can prevent being adversely affected.

  According to the superconducting cable system of the present invention, a cable that was normally used as a superconducting cable line can be used as a normal conducting cable line when the cooling function is lost, and can safely be used as a power transmission line when the cooling function is lost. Can be used.

It is a schematic sectional drawing which shows an example of a normal temperature insulated superconducting cable. It is a schematic sectional drawing which shows another example of a normal temperature insulated superconducting cable. 1 is an overall schematic configuration diagram of a superconducting cable system according to Embodiment 1. FIG. It is a schematic block diagram which shows an example of the structure of the terminal in the superconducting cable system which concerns on Embodiment 1. FIG. It is a schematic block diagram of the whole superconducting cable system which concerns on Embodiment 2. FIG. It is a schematic block diagram of the whole superconducting cable system which concerns on Embodiment 3. It is a schematic structure figure of the whole superconducting cable system concerning Embodiment 4.

  Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same reference numerals are used for the same or corresponding members.

  The superconducting cable system includes a superconducting cable provided at both ends of the superconducting cable and having a terminal conductor portion for connecting to a normal conductive power device via a current lead, and a cooling mechanism for the refrigerant. First, the structure of a superconducting cable (room temperature insulated superconducting cable) used in the superconducting cable system of the present invention will be described with reference to FIGS.

[Room-temperature insulated superconducting cable (1)]
FIG. 1 is a diagram illustrating an example of a room temperature insulated superconducting cable. A superconducting cable 101 shown in FIG. 1 includes one conductor portion 10 having a superconducting conductor layer 12 and a heat insulating tube 14 that houses the conductor portion 10, and the superconducting conductor layer 12 is cooled inside the heat insulating tube 14. Refrigerant flows. In addition, a main electrical insulating layer 15 is provided outside the heat insulating tube 14, and the insulation is performed at room temperature. Further, an external normal conducting member 16 is formed between the heat insulating tube 14 and the main electrical insulating layer 15.

  The conductor portion 10 typically has a former 11, a superconducting conductor layer 12, and a protective layer 13 in order from the center. The former 11 is a member that supports the superconducting conductor layer 12. For example, a solid body such as a stranded wire obtained by twisting a plurality of metal wires having an insulating coating such as enamel, an insulating pipe, a metal pipe, and a metal strip in a spiral shape It is possible to use a hollow body such as a spiral band that is wound around and formed into a cylindrical shape. When the former 11 is an internal normal conductive member that shunts an accident current (such as a short-circuit current), it may be formed of a metal normal conductive material such as copper or aluminum. When a hollow body such as a metal pipe is used, the internal space can also be used for the refrigerant flow path. In this example, the solid body is formed by twisting metal wires having an insulating coating.

  As the superconducting conductor layer 12, for example, a tape-shaped superconducting wire using an oxide superconducting conductor can be suitably used. Examples of the superconducting wire include a Bi2223-based silver sheathed superconducting wire (sheathed wire in which a filament made of an oxide superconducting conductor is disposed in a stabilizing metal such as Ag-Mn or Ag), an RE123-based thin film superconducting wire (RE: Rare earth elements (for example, Y, Ho, Nd, Sm, Gd, etc.) can be used as a laminated wire in which an oxide superconducting phase is formed on a metal substrate. The superconducting conductor layer 12 can be a single layer or a multilayer structure formed by spirally winding a plurality of superconducting wires around the outer periphery of the former 11. In this example, the superconducting conductor layer 12 has a multilayer structure. In the superconducting conductor layer 12, the above-described stabilizing metal or metal substrate of the superconducting wire also functions as an internal normal conducting member that shunts the accident current. Further, a cushion layer (not shown) may be interposed between the former 11 and the superconducting conductor layer 12, and the cushion layer can be formed by winding kraft paper or the like.

  A protective layer 13 is formed on the outer periphery of the superconducting conductor layer 12. The protective layer 13 electrically insulates the superconducting conductor layer 12 and the like disposed inside thereof from the heat insulating tube 14 and mechanically protects it. The protective layer 13 is formed by winding kraft paper or the like. Here, the conductor portion 10 (superconducting conductor layer 12) and the heat insulating tube 14 are electrically connected to each other at any location such as the end of a cable line or a joint, and have the same potential. The electrical insulation by the protective layer 13 provided outside the superconducting conductor layer 12 does not cause the main current flowing through the superconducting conductor layer 12 to be shunted to the heat insulating tube 14 (an unstable contact point with the heat insulating tube 14 is not formed). Therefore, it is not necessary to have a thickness necessary for insulation. The main insulation of the superconducting cable is ensured by the main electrical insulation layer 15 provided outside the heat insulating tube.

  The heat insulating tube 14 is a vacuum heat insulating tube having a double-pipe structure having an inner tube 14a that houses the conductor portion 10 therein and an outer tube 14b that houses the inner tube 14a inside. The inner pipe 14a functions as a refrigerant flow path through which the refrigerant 20 flows. The refrigerant 20 maintains the superconducting conductor layer 12 of the conductor portion 10 in a superconducting state. Typical examples of the refrigerant 20 include liquid nitrogen, liquid helium, and helium gas. By forming the heat insulating tube 14 with the inner tube 14a and the outer tube 14b covering the inner tube 14a, it is possible to suppress the temperature of the refrigerant 20 from rising due to heat entering from the outside. The heat insulating space between the inner tube 14a and the outer tube 14b is evacuated, thereby forming a vacuum heat insulating layer under normal conditions. In addition, if a heat insulating material such as super insulation or a spacer that separates the inner tube 14a and the outer tube 14b is disposed in the heat insulating space, the heat insulating performance of the heat insulating tube 14 can be further improved.

  In this example, the inner tube 14a and the outer tube 14b constituting the heat insulating tube 14 are corrugated tubes. By making both the pipes 14a and 14b corrugated pipes, the bending rigidity of the heat insulating pipe 14 (that is, the superconducting cable) can be reduced, and the laying of the superconducting cable inside the pipe can be made easier. . Both tubes 14a and 14b may be straight tubes. In a room-temperature insulated superconducting cable, a main electrical insulation layer (described later) is provided outside the heat insulation tube 14, so the heat insulation tube 14 is a voltage application site. The heat insulating tube 14 (the inner tube 14a and the outer tube 14b) is formed of stainless steel, aluminum, an alloy thereof, or the like.

  A main electrical insulating layer 15 is formed outside the heat insulating tube 14 (outer tube 14b). The main electrical insulation layer 15 satisfies the electrical insulation performance required as a cable line. The main electrical insulation layer 15 is made of a material having an excellent electrical insulation strength that has been used in existing normal conductive cables, typically an insulating resin such as cross-linked polyethylene (XLPE) used in CV cables. Can do. If the insulating resin such as cross-linked polyethylene is used, the main electrical insulating layer 15 can be easily formed by extruding the insulating resin on the outside of the heat insulating tube 14, specifically, the outer periphery of the external normal conducting member 16 described later by extrusion. Can be formed. In addition, an internal semiconductive layer or an external semiconductive layer (not shown) may be formed by extrusion simultaneously with the main electrical insulating layer 15 on the inner side or the outer side of the main electrical insulating layer 15 similarly to the normal conductive cable. . In addition, an outer shielding layer (not shown) made of a normal conducting material such as copper or aluminum is typically provided on the outer periphery of the main electrical insulating layer 15. The outer shielding layer provides a potential outside the main electrical insulating layer 15, and a normal conductive material can be used as in the case of a conventional power cable. Further, on the outer periphery of the outer shielding layer, a water shielding layer (not shown) that blocks moisture from the outside air and a corrosion prevention layer (not shown) that has a predetermined insulating property and protects the outer shielding layer are provided. .

  An external normal conducting member 16 is formed between the heat insulating tube 14 (outer tube 14b) and the main electrical insulating layer 15. The external normal conductive member 16 is used as a power transmission conductor when the refrigerant function is lost, and is formed of a normal conductive material such as a metal such as copper, aluminum, silver, or an alloy thereof. Further, the external normal conducting member 16 can also function as a shunt path for fault current during normal use as a superconducting cable line. The external normal conductive member 16 can be formed, for example, by winding a member conforming to the conductor of an existing normal conductive cable, such as a segment conductor made of a copper twisted wire, around the outer periphery of the outer tube 14b.

  By enlarging the conductor cross-sectional area of the external normal conducting member 16, it is possible to sufficiently secure the power transmission capacity when the cooling function is used as a normal conducting cable line and the flow path for the accident current. When the external normal conducting member 16 functions as a shunt path for the fault current, the conductor section 10 (former 11) due to a large fault current flowing is ensured by ensuring a sufficient conductor cross-sectional area of the external normal conducting member 16. And the temperature rise of the superconducting conductor layer 12) can be reduced, and the temperature rise of the refrigerant 20 in the heat insulating tube 14 can be suppressed.

  Furthermore, a tension member for laying may be provided on the outermost periphery of the superconducting cable 101 (not shown).

[Room-temperature insulated superconducting cable (2)]
FIG. 2 is a diagram showing another example of a room temperature insulated superconducting cable. The superconducting cable 102 shown in FIG. 2 is different from the superconducting cable 101 shown in FIG. 1 in that the tubular support member 17 is provided, and the basic configuration is the same as that of the superconducting cable 101. Explained.

  In the superconducting cable 102, the main electrical insulation layer 15 is not formed on the heat insulation pipe 14 (outer pipe 14b), and the external normal conduction is provided outside the tubular support member 17 disposed outside the heat insulation pipe 14 (outer pipe 14b). Conductive member 16 and main electrical insulating layer 15 are formed. That is, the tubular support member 17 is a member that supports the external normal conductive member 16 and the main electrical insulating layer 15 formed on the outside thereof, and it is important that the tubular support member 17 has a predetermined mechanical strength (mechanical characteristics). In order to make the superconducting cable 102 flexible, it is preferable that the tubular support member 17 also has a predetermined flexibility. In consideration of these points, a straight tube made of aluminum (including an alloy thereof), a corrugated tube made of stainless steel, or the like can be suitably used for the tubular support member 17. In addition, the tubular support member 17 may be formed of a non-metallic material such as a resin. Here, when the tubular support member 17 is formed of a normal conductive material, the function of the power transmission conductor when the refrigerant function is lost or the function of a normal current flow as a shunt path is the same as the external normal conductive member 16 described above. A part can be shared with the tubular support member 17.

  When the tubular support member 17 is provided, the external normal conducting member 16 is formed between the tubular support member 17 and the main electrical insulating layer 15 as illustrated in FIG.

  By providing such a tubular support member 17, it is possible to separately handle the heat insulating tube 14 in which the conductor portion 10 is accommodated and the tubular support member 17 provided with the external normal conducting member 16 and the main electrical insulating layer 15. it can.

(Embodiment 1)
Next, with reference to FIGS. 3 and 4, the overall schematic configuration of the superconducting cable system according to the first embodiment and the schematic configuration of the terminal structure in the superconducting cable system will be described.

  This system includes a superconducting cable 100 and a refrigerant cooling mechanism 200, and terminals 150a and 150b for connecting to a normal conductive device (for example, a circuit breaker) in the cable line at both ends of the superconducting cable 100. Is provided. The superconducting cable 100 is, for example, the above-described room-temperature insulated superconducting cable shown in FIGS. 1 and 2, and a main electrical insulating layer 15 is provided outside a heat insulating tube (vacuum heat insulating tube) 14. An external normal conducting member 16 is formed between the electrical insulating layer 15 and the electrical insulating layer 15. Here, the case where the configuration of superconducting cable 100 is the same as that of superconducting cable 101 shown in the drawing will be described as an example.

  The structure of the terminals 150a and 150b installed at both ends of the superconducting cable 100 will be described. First, with reference to FIG. 4, the structure of one of the terminals 150a and 150b will be described.

[Terminal conductor]
The terminal 150a includes a terminal conductor portion 30 for electrically connecting the superconducting cable 100 and the connection conductor 60 of the normal conductive power device via a current lead. The terminal conductor portion 30 includes a first current lead 31 that connects the conductor portion 10 of the superconducting cable 100 and the connecting conductor 60 of the power device, an external normal conducting member 16 of the superconducting cable 100, and a connecting conductor 60 of the power device. A second current lead is provided.

  In this example, an end treatment for removing the main electrical insulating layer at the end of the superconducting cable 100 is performed, and the end of the cable 100 is inserted into the soot tube 51 to form the terminal insulating portion 50. The heat insulating tube 14 of the cable 100 protrudes from the terminal insulating portion 50 to the outside, and the conductor portion 10 is drawn from the end of the heat insulating tube 14. A connecting portion between the conductor portion 10 and the first current lead 31 is provided outside the terminal insulating portion 50, and a heat insulating container 40 is formed so as to accommodate the connecting portion. Further, a connection part between the external normal conducting member 16 and the second current lead 32 formed outside the heat insulating tube 14 is also provided outside the terminal insulating part 50.

  The terminal insulating part 50 is the same as the terminal of the existing normal conducting cable, and the porcelain pipe 51 may be made of, for example, porcelain or resin (for example, epoxy resin).

  At the portion protruding from the terminal insulating portion 50 at the end of the superconducting cable 100, the main electrical insulating layer or the like is removed, the external normal conducting member 16 is exposed, and the conductor portion 10 is pulled out from the end of the heat insulating tube 14. It is. At the end of the drawn conductor portion 10, the protective layer and the like are removed by terminal treatment, the superconducting conductor layer 12 is exposed, and a terminal fitting (not shown) is attached to the outside of the exposed superconducting conductor layer 12. It has been. An end portion of the heat insulating pipe 14 is connected to the heat insulating container 40, and the refrigerant flow path inside the heat insulating pipe 14 and the internal space of the heat insulating container 40 communicate with each other.

  One end of the first current lead 31 is housed in the heat insulating container 40 and is electrically connected to the conductor portion 10 (superconducting conductor layer 12) drawn from the end portion of the heat insulating tube 14 via a terminal fitting. The end side is drawn out to the outside (room temperature side) of the heat insulating container 40 and connected to the connection conductor 60 of the power device 60. On the other hand, the second current lead 32 has one end side electrically connected to the external normal conducting member 16 formed outside the heat insulating tube 14, and the other end side connected to the connection conductor 60 of the power device. The first current lead 31 and the second current lead 32 are made of a normal conductive material such as copper or aluminum, for example. In addition, the first current lead 31 has a heat insulating member 36 on the outer peripheral surface, and the heat insulating member 36 is fitted and connected to the heat insulating container 40 to reduce the sealing of the refrigerant and the intrusion heat from the outside. It is carried out.

  Further, the terminal conductor portion 30 includes a blocking means 33a that blocks the connection between the conductor portion 10 and the external normal conducting member 16 and the connection conductor 60 of the power device. The blocking means 33a includes a first blocking means 34 that blocks the connection on the conductor 10 side, and a second blocking means 35 that blocks the connection on the external normal conducting member 16 side. Therefore, it is possible to individually connect and disconnect the conductor portion 10 side and the external normal conducting member 16 side. In this example, the first cut-off means 34 is configured by providing a switch that can be connected / cut off in the middle of the first current lead 31, and the first cut-off switch 34 is provided in the middle of the second current lead 32 by providing a switch that can be connected / cut off. Two blocking means 35 are configured. The first interrupting means 34 and the second interrupting means 35 are configured by a switch that can connect and disconnect the first current lead 31 and the second current lead 32, and in the middle of the first current lead 31 and the second current lead 32. It may be configured by attaching a detachable bond wire. In this case, the first current lead 31 and the second current lead 32 can be connected / cut off by attaching / detaching the bond wire. Further, the connection / disconnection operation of the first interruption means 34 and the second interruption means 35 may be performed automatically or manually, and when connecting / disconnecting by attaching / detaching the bond line, an operator manually performs the operation. You may attach / remove the bond wire.

  The inside of the heat insulating container 40 communicates with the inside of the heat insulating pipe 14 and is filled with the refrigerant 20 flowing through the heat insulating pipe 14. In this example, the heat insulating container 40 is a double-structure vacuum heat insulating container having an inner container and an outer container, and the heat insulating space between the inner container and the outer container is evacuated to form a vacuum heat insulating layer. Yes. The heat insulating container 40 (inner container and outer container) is made of stainless steel, aluminum, an alloy thereof, or the like.

  An insulating member (not shown) is interposed between the first current lead 31 and the heat insulating container 40 so that no current flows between the first current lead 31 and the heat insulating container 40. This insulating member may be provided between the first current lead 31 and the heat insulating member 36. For example, when assembling the connection structure at the site, an insulating member is formed on the first current lead 31 in advance at a factory or the like, and a heat insulating member 36 is formed thereon, and the first current lead 31 is formed at the site. Is inserted into the fitting portion 42 provided in the heat insulating container 40 to fit the first current lead 31 and the heat insulating container 40 together. As described above, since the first current lead 31 includes the heat insulating member 36, it is easy to assemble the connection structure on site. Further, as shown in the figure, by making the heat insulating member 36 of the first current lead 31 and the fitting portion 42 of the heat insulating container 40 overlap, it is possible to effectively suppress the intrusion heat from the outside. Similarly, the insulation pipe 14, the branch refrigerant pipe 53, and the heat insulation container 40 are fitted in the connection place between the heat insulation container 40 and the heat insulation pipe 14 and the connection place between the heat insulation container 40 and the branch refrigerant pipe 53 (described later). , Overlapping. A flange portion is formed on the outer periphery of the heat insulating member 36, and this flange portion is brought into contact with the fitting portion 42 for use in positioning, or the flange portion is fixed to the heat insulating container 40 (fitting portion 42). Also good.

  A branch refrigerant pipe 53 for sending the refrigerant 20 flowing through the heat insulation pipe 14 to the cooling mechanism 200 (described later, see FIG. 3) is connected to the heat insulation container 40. In the case of a room-temperature insulated superconducting cable, since the main electric insulating layer is not provided between the superconducting conductor layer 12 and the heat insulating tube 14 which are high voltage portions, the heat insulating tube 14 has a high potential. Therefore, the heat insulating container 40 to which the heat insulating pipe 14 is connected and the branch refrigerant pipe 53 connected to the heat insulating container 40 are also at a high potential. On the other hand, since the cooling mechanism 200 including the refrigerator and the refrigerant circulation mechanism is normally provided in the grounding part (low voltage part), it has a grounding potential (low potential). Therefore, when the branch refrigerant pipe 53 is directly connected to the cooling mechanism 200, there is a problem that a voltage cannot be applied (a ground fault occurs and an abnormal current flows), and thus cannot be established as a power transmission line. Therefore, in this example, in order to connect the branch refrigerant pipe 53 and the cooling mechanism 200 in an electrically insulated state, an insulating joint 55 having a predetermined dielectric strength is provided between the branch refrigerant pipe 53 and the cooling mechanism 200. ing. As the branch refrigerant pipe 53, a vacuum heat insulation pipe having a double-pipe structure can be used similarly to the heat insulation pipe. The insulating joint 55 is provided with a heat insulating portion 56 on the outside thereof, and the heat insulating container 40 is provided with an insulating member (not shown) on the outside thereof.

  The heat insulating container 40 is further provided with a release valve (not shown) for discharging the vaporized refrigerant 20 when the liquid refrigerant 20 is vaporized and the internal pressure is increased. Thereby, when the cooling function is lost, when the refrigerant 20 is vaporized due to the temperature rise and the internal pressure becomes equal to or higher than the specified pressure, the vaporized refrigerant can be discharged from the heat insulating container 40, and the heat insulating container 40 and the heat insulating material communicating with the heat insulating container 40 can be discharged. It is possible to prevent the internal pressure of the pipe 14 from becoming excessive.

  Next, the structure of the other terminal 150b shown in FIG. 3 will be described. The terminal 150b has almost the same configuration as that of the one terminal 150a described with reference to FIG. A current lead 32 and a blocking means 33b are provided. However, the blocking means 33b is configured by providing a switch that can be connected and disconnected in the middle of the current lead that is formed by combining the first current lead and the second current lead. By this interruption means 33, the connection between the conductor part 10 and the external normal conducting member 16 and the connection conductor 60 of the power equipment can be interrupted. It is possible to simultaneously connect and disconnect the conductive member 16 side. The blocking means 33b may be configured by attaching a detachable pond wire in the same manner as the first blocking means 34 and the second blocking means 35 described above. Further, the blocking means 33b may include a first blocking means 34 and a second blocking means 35 in the same manner as the blocking means 33a described above. Similarly to the terminal 150a, the terminal 150b connects the branch refrigerant pipe 53 and the refrigerant pipe 300 (see FIG. 3 described later) connected to the cooling mechanism 200 in an electrically insulated state. An insulating joint 55 (see FIG. 4) is provided between the pipe 53 and the refrigerant pipe 300.

[Cooling mechanism]
The refrigerant cooling mechanism 200 is installed on one terminal 150a side of the superconducting cable 100. Normally, the refrigerant 20 cooled by the cooling mechanism 200 is supplied from one end 150a of the superconducting cable 100 to the heat insulating pipe 14, discharged from the other end 150b, and returned to the cooling mechanism 200 again through the refrigerant pipe 300. It is. Or conversely, the refrigerant 20 is circulated. Specifically, the refrigerant 20 cooled by the cooling mechanism 200 is filled into the heat insulating container 40 of one terminal 150a through the branch refrigerant pipe 53, passes through the heat insulating pipe 14, and then the heat insulating container 40 of the other terminal 150b. Filled. Thereafter, the refrigerant is sent from the heat insulating container 40 of the other terminal 150b to the refrigerant pipe 300 through the branch refrigerant pipe 53, and returned to the cooling mechanism 200 through the refrigerant pipe 300. The circulation of the refrigerant 20 cools the superconducting conductor layer 12 of the conductor portion 10 accommodated in the heat insulating tube 14 to a cryogenic temperature and maintains the superconducting state. In this example, the cooling mechanism 200 is returned to the cooling mechanism 200 via the refrigerant pipe 300, and the refrigerant 210 that has been cooled to a predetermined low temperature again is cooled with the refrigerator 210 that has risen in temperature compared to the supply start time. A circulation mechanism (not shown) that pumps the refrigerant 20 to the circulation path including the heat insulation pipe 14 and the refrigerant pipe 300, and a cooling tower 215 are provided. A cooling tower 215 is connected to the refrigerator 210 to cool the heat radiation side (high temperature side) of the refrigerator 210 itself. A pump can be suitably used for the circulation mechanism. The cooling mechanism 200 preferably includes a refrigerant discharge valve (not shown) for the refrigerant. When the cooling function is lost, the liquid refrigerant 20 is heated and vaporized, so by opening the refrigerant discharge valve, the vaporized refrigerant 20 is discharged from the circulation path, and the heat insulating pipe 14, the heat insulating container 40, and the refrigerant pipe 300 are discharged. It can be controlled so that the internal pressure does not become excessive.

[Refrigerant tube]
The refrigerant pipe 300 is laid in parallel with the superconducting cable 100 and constitutes one of the forward path and the return path of the refrigerant 20. In this example, the refrigerant pipe 300 constitutes the return path of the refrigerant 20. As the refrigerant tube 300, a vacuum heat insulating tube having a double tube structure can be suitably used, as with the heat insulating tube 14 of the superconducting cable 100. One end side (left side in FIG. 4) of the refrigerant pipe 300 is connected to the cooling mechanism 200, and the other end side (right side in FIG. 4) is connected to the heat insulating container 40 of the other terminal 150b via the branch refrigerant pipe 53. . Here, when a plurality of superconducting cables are provided, the refrigerant circulation path may be configured by using a heat insulating pipe of any of the superconducting cables without using the refrigerant pipe.

<System operation procedure>
The superconducting cable system according to the first embodiment in which the terminal conductors described above are provided at both ends of the superconducting cable is operated as follows.

  (1) Since the superconducting conductor layer 12 is maintained in the superconducting state by the refrigerant 20 flowing in the heat insulating pipe 14 during normal operation of the cooling mechanism 200 of the refrigerant, the conductor portion 10 (superconducting conductor layer 12 ) Is used as the main power transmission conductor, and the superconducting cable 100 is operated as a superconducting cable line. Specifically, in each blocking means 33a, 33b, the first current lead 31 and the second current lead 32 are connected, and between the conductor 10 and the external normal conducting member 16 and the connection conductor 60 of the power device. Is connected.

  (2) When the cooling mechanism of the refrigerant does not operate normally and the superconducting conductor layer 12 cannot be maintained in the superconducting state and the cooling function is lost, an alarm is issued from the superconducting cable system, and the breaker on the system control system side operates. Superconducting cable 100 is disconnected from the transmission system. At this time, when the refrigerator 210 and the circulation mechanism (pump) of the cooling mechanism 200 are stopped and the temperature of the refrigerant 20 rises, the refrigerant 20 is vaporized and the pressure rises. The refrigerant 20 vaporized by the temperature rise is discharged from the circulation path by opening a discharge valve provided in the heat insulating container 40 and a refrigerant discharge valve provided in the cooling mechanism 200.

  When the state of the superconducting cable 100 is confirmed and it is determined that power transmission by the cable 100 is necessary, the superconducting cable 100 is operated as a normal conducting cable line. Specifically, in one of the blocking means 33a, the first current lead 31 is blocked by the first blocking means 34, the conductor part 10 side is blocked, and the second current lead 31 is blocked by the second blocking means 35. 32 is connected, and the external normal conducting member 16 side is connected. In the other blocking means 33b, the first current lead 31 and the second current lead 32 are connected, and the conductor 10 side and the external normal conducting member 16 side are connected. Thus, power transmission to the conductor portion 10 can be stopped, and power can be transmitted by the external normal conductive member 16 by using the external normal conductive member 16 as a main power transmission conductor. After the operation of the shut-off means is completed, the circuit breaker on the system control system side is returned, and power is transmitted by the external normal conducting member 16 in a state where power transmission by the conductor 10 is stopped. In addition, although the power transmission capacity at the time of normal conducting cable operation becomes small compared with the power transmission capacity at the time of superconducting cable operation, it can be effectively used as valuable power when the cooling function is lost by supplying even a little power.

  (3) When the cooling mechanism 200 is restored while the superconducting cable 100 is operated as a normal conducting cable line, supply of the refrigerant 20 is started by the restored cooling mechanism 200 and the refrigerant 20 is circulated. Further, power transmission is temporarily stopped by the circuit breaker on the system control system side, and the superconducting cable 100 is disconnected from the power transmission system. It is confirmed that the superconducting cable 100 satisfies a predetermined function as a superconducting cable line, the first blocking means 34 of one blocking means 33a is switched to the connected state, and each blocking means 33a, 33b is connected to the conductor 10 side and the outside The normal conductive member 16 side is connected. After completion of the operation of the interruption means, the circuit breaker on the system control system side is restored, and the superconducting cable 100 is operated again as a superconducting cable line by using the conductor portion 10 as a main power transmission conductor.

<Effect>
According to the superconducting cable system according to the first embodiment described above, the superconducting cable 100 can be used as a superconducting cable line during normal times, and the cable 100 can be used as a normal conducting cable line when the cooling function is lost. Since the external normal conductive member 16 used for the power transmission conductor when the cooling function is lost is provided outside the heat insulating tube 14, heat can be dissipated even if heat is generated by power transmission, as with the existing normal conductive cable. Even if heat is generated by power transmission, power transmission is possible within the allowable temperature range. Therefore, in the event of a disaster, when the cooling mechanism 200 is inoperable and the standby line cannot be used, power can be transmitted as a normal conducting cable for emergency evacuation and can be used as a power transmission line. . Also, by stopping the power transmission by the conductor 10 until the cooling mechanism is restored, the temperature rise due to the heat generation of the conductor 10 due to the power transmission can be prevented, and the excessive temperature rise of the superconducting conductor layer 12 can be avoided. Can do. Furthermore, by stopping the power transmission of the conductor portion 10, the temperature rise in the heat insulating tube 14 can be suppressed for a short time, so that the superconducting cable line can be quickly restored after the cooling mechanism is restored. .

  Further, in the superconducting cable system according to the first embodiment, when the cooling function is lost, the one breaking means 33a causes the conductor section 10 side to be cut off by the first breaking means 34, and the other breaking means 33b The part 10 side is connected. Therefore, when the normal conducting cable is used, the conductor unit 10 side and the external normal conducting member 16 side are connected in the other blocking means 33b. Therefore, a potential difference does not occur between the conductor portion and the external normal conducting member, and damage to the main electrical insulating layer such as dielectric breakdown can be prevented.

  Furthermore, both of the blocking means 33a and 34 can respectively cut off the conductor portion side and the external normal conducting member side, and the superconducting cable 100 is connected to the power transmission system on the superconducting cable system side separately from the system control system side. It is possible to separate from.

  In the superconducting cable system according to Embodiment 1 described above, the embodiment in which only the external normal conducting member 16 formed outside the heat insulating tube 14 is used as a power transmission conductor has been described. In the following, an embodiment will be described in which the conductor 10 (internal normal conducting member such as a former) housed in the heat insulating tube 14 is also used as a power transmission conductor when the cooling function is lost. Embodiments 2 to 4 described below with reference to FIGS. 4 to 6 are characterized in that the heat insulating performance of the vacuum heat insulating tube 14 is reduced in order to allow heat dissipation of the conductor portion 10.

(Embodiment 2)
With reference to FIG. 5, the superconducting cable system according to the second embodiment will be described. This system includes a vacuum pump 410 that communicates with the heat insulation space of the vacuum heat insulation pipe 14, a gas supply source 420, a first valve 440 that selects a communication state of the vacuum pump 410 and the gas supply source 420 with respect to the heat insulation space, and an opening / closing valve 470. This is different from the system of the first embodiment shown in FIG.

  The refrigerant cooling mechanism 200 normally cools the refrigerant 20 that cools the superconducting conductor layer 12 to a predetermined temperature, and pumps the refrigerant 20 to a circulation path including the heat insulating pipe 14 and the refrigerant pipe 300 of the superconducting cable 100.

  On the other hand, when the cooling function 200 is not functioning properly and the cooling function is lost, the refrigerant 20 is not cooled and circulated, and the heat insulating space of the vacuum heat insulating tube 14 is filled with gas from the gas supply source 420, and the heat insulating performance of the vacuum heat insulating tube 14 Reduce. The conductor portion 10 (internal normal conductive member) is used as a power transmission conductor by enabling the heat radiation of the conductor portion 10 and suppressing the temperature rise caused by the heat generated by the power transmission of the conductor portion 10. That is, when the cooling function is lost, the internal normal conductive member of the conductor portion 10 is also used for power transmission, as compared with the above-described first embodiment in which only the external normal conductive member is used as a normal conductor cable line. Used for conductors. At this time, in each of the blocking means 33a and 33b, the conductor portion 10 side and the external normal conducting member 16 side are connected.

  Details of the configuration of each part of this system will be described below with reference to FIG.

[Vacuum pump]
The vacuum pump 410 is a pump that evacuates the heat insulating space of the vacuum heat insulating tube 14. For example, when the superconducting cable 100 is operated as a normal conducting cable line when the cooling function is lost, the heat insulating space is filled with gas and becomes non-vacuum. After that, when the cooling mechanism 200 is restored and the operation as a superconducting cable line becomes possible, the vacuum pump 410 is used to return the heat insulation space to a vacuum again. If the heat insulation space is returned to a vacuum by evacuation by the vacuum pump 410, the superconducting cable 100 can be used again as a superconducting cable line.

[Gas supply source]
The gas supply source 420 contains a gas that is a heat conductive material supplied to the heat insulating space of the vacuum heat insulating tube 14. When the cooling function is lost, the gas supply source 420 may be, for example, a closed container such as a tank, or simply an open end of the communication pipe 450 (described later) and an open space of the atmosphere connected to the open end. When the gas supply source 420 is a tank, a gas such as nitrogen gas serving as a heat conduction material is stored in the tank. When the open space of the atmosphere is used as the gas supply source 420, air becomes a heat conductive material. When the superconducting cable line is restored by evacuating the heat insulating tube 14 again, it is not preferable that moisture in the atmosphere enter the heat insulating space, and nitrogen gas or dry air with less water content is contained in the gas supply source 420. It is preferable to keep it. Further, when the heat insulating pipe 14 is opened to the atmosphere, it is also effective to provide a deaeration means (not shown) for removing moisture in the atmosphere in the middle of the communication pipe 450.

[First valve]
The first valve 440 is a valve that selectively connects the vacuum pump 410 and the gas supply source 420 to the heat insulation space of the vacuum heat insulation pipe 14. In this example, a communication pipe 450 (described later) connected to the heat insulation space is branched, an opening / closing valve 440A is provided in one branch pipe 450L, and an opening / closing valve 440B is provided in the other branch pipe 450R. The first valve 440 is configured. Of course, the first valve 440 may be constituted by a three-way valve provided at a branch point of the communication pipe 440 instead of the two on-off valves 440A and 440B. In addition, an open / close valve 470 serving as a source valve is provided in the communication pipe 450 midway from the heat insulation space to the branch point. When operating the system of this example as a superconducting cable line, the vacuum insulation tube 14 is usually operated with a vacuum seal. Normally, the on-off valve 470 is closed and the vacuum insulation tube 14 is sealed to provide a cooling function. When lost, the opening / closing valve 470 is opened.

[Communication pipe]
The communication pipe 450 is a pipe connecting the heat insulation space of the vacuum heat insulation pipe 14 and the vacuum pump 410 or the gas supply source 420. In this example, one communication pipe 450 is pulled out from the heat insulating space, and the middle of the communication pipe 450 is branched into two branches. One branch pipe 450L is connected to the vacuum pump 410, and the other branch pipe 450R is connected to the gas supply source 420.

[compressor]
If necessary, a compressor 460 may be provided in the middle of the branch pipe 450R between the gas supply source 420 and the open / close valve 440B. The compressor 460 can pressurize the gas to quickly fill the heat insulation space of the vacuum heat insulation pipe 14 with the gas.

  The vacuum pump 410, the gas supply source 420, the first valve 440, the communication pipe 450, and the compressor 460 described above may be installed from the beginning of the construction of the superconducting cable system or installed afterwards. For example, the vacuum pump 410, the gas supply source 420, the first valve 440, the communication pipe 450, and the compressor 460 may be installed from the beginning of the construction of the superconducting cable system, or mounting for attaching these members to the superconducting cable system. A part may be provided and installed after the cooling function is lost. Alternatively, a short communication pipe and an opening / closing valve 470 are connected in advance to the vacuum heat insulation pipe 14, and this is used as a mounting portion to connect the remaining communication pipe, vacuum pump 410, gas supply source 420 and compressor 460 when the cooling function is lost. May be connected. In this case, normally, the on-off valve 470 is closed and the vacuum heat insulating tube 14 is sealed, and in this state, it can be operated as a superconducting cable line. In addition, by installing the vacuum pump 410 from the beginning of the construction of the superconducting cable system, the vacuum pump 410 can also be used for evacuating the vacuum heat insulating tube 14 when the superconducting cable system is constructed.

  The vacuum pump 410 and the gas supply source 420 are at ground potential. On the other hand, the superconducting cable 100 is a room temperature insulation type, and when used in a power transmission line, the vacuum heat insulating tube 14 is at a high potential, so that an insulating joint 455 is interposed between the vacuum heat insulating tube 14, the vacuum pump 410, and the gas supply source 420. Is provided. In this example, an insulating joint 455 is provided between the open / close valve 470 and the vacuum pump 410 and the gas supply source 420 in the communication pipe 450.

<System operation procedure>
The superconducting cable system according to the second embodiment described above is operated as follows.

  (1) When the refrigerant cooling mechanism 200 is operating normally, the first valve 440 (open / close valves 440A and 440B) and the open / close valve 470 are closed, and the heat insulating space of the vacuum heat insulating pipe 14 is maintained in a vacuum state. . In addition, since the superconducting conductor layer 12 is maintained in a superconducting state by the refrigerant 20 flowing in the heat insulating pipe 14, the conductor portion 10 (superconducting conductor layer 12) is used as a main power transmission conductor, and the superconducting cable 100 is used as the superconducting cable. Operate as a track. Specifically, in each blocking means 33a, 33b, the first current lead 31 and the second current lead 32 are connected, and between the conductor 10 and the external normal conducting member 16 and the connection conductor 60 of the power device. Is connected.

  (2) When the cooling function 200 of the refrigerant does not operate normally and the cooling function is lost when the superconducting conductor layer 12 cannot be maintained in the superconducting state, the superconducting cable 100 is disconnected from the power transmission system as described in the first embodiment, and The refrigerator 210 and the circulation mechanism (pump) of the cooling mechanism 200 are stopped, and the refrigerant 20 vaporized by the temperature rise is discharged from the circulation path. Nitrogen gas may be introduced into the vacuum heat insulating tube 14 (refrigerant flow path) in order to shorten the time required for temperature increase. After confirming that the temperature of the discharged refrigerant 20 has risen to a predetermined temperature, gas is supplied from the gas supply source 420 to the heat insulating space of the vacuum heat insulating tube 14. Specifically, the opening / closing valve 440B and the opening / closing valve 470 are opened. Since the heat insulation space before the opening is kept in a vacuum state, by opening the on-off valve 440B and the on-off valve 470, gas is supplied from the gas supply source 420 to the heat insulation space by natural inflow, and the heat conduction material is supplied to the heat insulation space. The gas which becomes becomes. By this gas filling, the heat insulating performance of the vacuum heat insulating tube 14 is lowered, and the heat insulating tube 14 becomes a heat transfer tube. Here, as another means for quickly increasing the temperature of the refrigerant, it is also effective to supply a small amount of gas from the gas supply source 420 to the heat insulation space of the vacuum heat insulation pipe 14 to slightly reduce the heat insulation performance of the heat insulation pipe 14. If the heat insulation performance of the heat insulating tube 14 is lowered too much when the refrigerant is at a low temperature to some extent, the surface temperature of the heat insulating tube 14 may decrease, causing problems such as freezing. It is necessary to adjust the gas supply amount. When this gas supply becomes excessive, it is effective to evacuate with the vacuum pump 410.

  In addition, until the heat insulation performance of the vacuum heat insulation pipe 14 is lowered, as described in the first embodiment, the first cut-off means 34 of one of the cut-off means 33a is switched to the cut-off state to cut off the connection on the conductor 10 side. At the same time, the second blocking means 35 and the other blocking means 33b of one blocking means 33a are connected, and the external normal conducting member 16 side is connected. After the operation of the breaker is completed, the breaker on the system control system side is restored, and the power transmission by the conductor 10 is stopped, power is transmitted by the external normal conductive member 16, and the superconducting cable 100 is operated as a normal conductive cable line. To do.

  (3) After confirming that the heat insulation space of the vacuum heat insulation container 14 is filled with the gas as the heat conduction material, the heat insulation performance of the vacuum heat insulation pipe 14 is reduced, and the heat radiation of the conductor 10 is enabled, the system control system Power transmission is temporarily stopped by the circuit breaker on the side, and the superconducting cable 100 is disconnected from the power transmission system. Then, the first blocking means 34 of the one blocking means 33a is switched to the connected state, and the conductor 10 side and the external normal conducting member 16 side are connected to each of the blocking means 33a and 33b. After the operation of the shut-off means is completed, the circuit breaker on the system control system side is restored, and not only the external normal conductive member 16 but also the conductor portion 10 (internal normal conductive member) is used as a power transmission conductor for power transmission. In this case, by using only the external normal conductive member for the power transmission conductor and operating as a normal conductive cable line, the conductor 10 (internal normal conductive member) is also used for the power transmission conductor. It is possible to increase the transmission capacity during normal conductive cable operation.

  (4) While the superconducting cable 100 is operated as a normal conducting cable line using the conductor part 10 (internal normal conducting member) as a conducting conductor, once the cooling mechanism is restored, power transmission is stopped once. Disconnect superconducting cable 100 from the transmission system. Then, the first blocking means 34 of one blocking means 33a is switched to a blocking state, the connection on the conductor part 10 side is blocked, and the second blocking means 35 of one blocking means 33a and the other blocking means 33b are connected. Thus, the external normal conducting member 16 side is brought into a connected state. After the operation of the shut-off means is completed, the circuit breaker on the system control system side is returned, and power is transmitted by the external normal conducting member 16 in a state where power transmission by the conductor 10 is stopped. Further, after the power transmission by the conductor portion 10 is stopped, the open / close valve 440B is closed to cut off the communication between the gas supply source 420 and the heat insulating space of the vacuum heat insulating pipe 14, and the open / close valve 440A is further opened. Then, the gas in the heat insulating space of the vacuum heat insulating tube 14 is exhausted by the vacuum pump 410, and the heat insulating space is evacuated to a predetermined degree of vacuum.

  (5) When the heat insulation space of the vacuum heat insulation pipe 14 reaches a predetermined degree of vacuum, the opening / closing valve 440A and the opening / closing valve 470 are closed, and supply of the refrigerant 20 is started by the returned cooling mechanism 200, and the refrigerant 20 is circulated. Further, power transmission is temporarily stopped by the circuit breaker on the system control system side, and the superconducting cable 100 is disconnected from the power transmission system. It is confirmed that the superconducting cable 100 satisfies a predetermined function as a superconducting cable line, the first blocking means 34 of one blocking means 33a is switched to the connected state, and each blocking means 33a, 33b is connected to the conductor 10 side and the outside The normal conductive member 16 side is connected. After completion of the operation of the interruption means, the circuit breaker on the system control system side is restored, and the superconducting cable 100 is operated again as a superconducting cable line by using the conductor portion 10 as a main power transmission conductor.

<Effect>
According to the superconducting cable system according to the second embodiment described above, the following functions and effects are provided in addition to the functions and effects of the first embodiment. According to this configuration, when the cooling function is lost, the heat insulating performance of the vacuum heat insulating tube 14 is lowered, and the normal vacuum heat insulating tube 14 can be used as a heat transfer tube. Therefore, when the superconducting cable 100 is operated as a normal conductive cable line, even if the conductor 10 (internal normal conductive member) is also used as a power transmission conductor, the heat of the conductor 10 is dissipated and the temperature of the conductor 10 is The rise can be suppressed. Therefore, it is possible to increase the power transmission capacity when operating the normal conducting cable while avoiding the temperature rise of the conductor portion 10.

  Further, by selectively communicating the vacuum pump 410 and the gas supply source 420 to the heat insulation space of the vacuum heat insulation pipe 14, the vacuum heat insulation pipe 14 is again evacuated by the vacuum pump 410 after the cooling mechanism 200 is restored. Returning, the superconducting cable 100 can be operated again as a superconducting cable line. In particular, by introducing gas into the heat insulating space or the refrigerant flow path of the vacuum heat insulating tube 14, the temperature of the cable can be efficiently increased when the cooling function is lost.

  Furthermore, by selectively connecting / cutting off the first current lead 31 by the first cut-off means 34 and controlling the power transmission to the conductor portion 10, the heat insulation performance of the vacuum heat insulation pipe 14 is reliably lowered when the cooling function is lost. Power transmission by the external normal conducting member 16 can be performed in a state where power transmission by the conductor portion 10 is stopped while the vacuum pump 410 is evacuated to a predetermined vacuum degree when the cooling mechanism is restored.

  In the system of the second embodiment described above, the vacuum pump 410 and the gas supply source 420 are connected to the heat insulation space of the vacuum heat insulation pipe 14 via the communication pipe 450 to supply gas to the heat insulation space of the vacuum heat insulation pipe 14 or vacuum. The case where the heat insulation space of the heat insulation pipe 14 is evacuated has been described. Further, the vacuum pump 410 and the gas supply source 420 may be connected to the heat insulation space of the vacuum heat insulation container 40 through the communication pipe as well as the vacuum heat insulation pipe 14. With this configuration, gas can also be supplied to the heat insulating space of the vacuum heat insulating container 40 to reduce the heat insulating performance of the heat insulating container 40, and heat generated by the conductor 10 in the heat insulating container 40 can be radiated. Also, the heat insulating space of the vacuum heat insulating container 40 can be evacuated to return the heat insulating space to a vacuum again, and can be used again as a superconducting cable line.

  If the refrigerant cooling mechanism 200 does not operate normally due to an unexpected situation such as a natural disaster, it is necessary to check the state of the superconducting cable 100 and to repair the superconducting cable as necessary. Therefore, if the vacuum pump 410, the gas supply source 420, and the like have not been installed since the beginning of the construction of the superconducting cable system, there are few problems even if they are installed later using this period. Rather, it may be more dangerous to connect the communication pipe 450 etc. to the vacuum insulation pipe 40, which is at high voltage during normal operation (when superconducting cable is in operation). It is preferable to install.

(Embodiment 3)
Next, a superconducting cable system according to Embodiment 3 in which the heat insulating space of the vacuum heat insulating tube of the superconducting cable is filled with liquid when the cooling function is lost and the superconducting cable is operated as a normal conducting cable line will be described with reference to FIG. . Since the basic configuration of this system is the same as that of the second embodiment shown in FIG. 5, differences will be mainly described. This system includes a liquid supply source 520 that stores a liquid serving as a heat conduction material, a supply pipe 522 that supplies liquid from the liquid supply source 520 to the heat insulation space of the vacuum heat insulation pipe 14, and a heat insulation space of the vacuum heat insulation pipe 14. A discharge pipe 524 that discharges the liquid, and a second valve 526 that communicates and blocks the liquid supply source 520 and the heat insulation space of the vacuum heat insulation pipe 14 are provided.

[Liquid supply source]
The liquid supply source 520 stores a liquid serving as a heat conductive material supplied to the heat insulating space of the vacuum heat insulating tube. In general, a tank can be suitably used as the liquid supply source 520. As a specific example of the liquid, inexpensive and easily available water can be used. In this example, the liquid supply source 520 is provided with a pump 528 (pressure feeding means). The pump 528 pressurizes the liquid and pumps it to the heat insulating space. Furthermore, the liquid supply source 520 may be provided with a heat dissipation mechanism (not shown) as necessary. The heat dissipating mechanism cools the liquid returned from the discharge pipe 524 to the liquid supply source 520 again. A heat dissipating fin can be provided on the outer periphery of the tank constituting the liquid supply source 520, or a structure such as a radiator can be used.

[Supply and discharge pipes]
The liquid supply source 520 and the heat insulation space of the vacuum heat insulation pipe 14 are communicated with each other via a supply pipe 522 and a discharge pipe 524. The refrigerant 20 is circulated using the liquid supply source 520, the supply pipe 522, the vacuum heat insulation pipe 14 and the discharge pipe 524 as distribution channels. In this example, a supply pipe 522 is connected to one end side (the left side in FIG. 6) of the vacuum heat insulating pipe 14, and a discharge pipe 524 is connected to the other end side (the right side in FIG. 6).

[Second valve]
Each of the supply pipe 522 and the discharge pipe 524 is provided with opening / closing valves 526, 526, and the both opening / closing valves constitute a second valve 526. By opening the second valve 526, liquid can be supplied from the liquid supply source 520 to the heat insulation space of the vacuum heat insulation pipe 14, and by closing the valves 526, 526, the liquid supply source 520 and the vacuum heat insulation pipe 14 are insulated. Shut off the space.

  Also in the system of the third embodiment, as in the second embodiment, the liquid supply source 520, the supply pipe 522, the discharge pipe 524, and the second valve 526 are installed from the beginning of the construction of the superconducting cable system. It doesn't matter whether it is installed in. For example, components such as the liquid supply source 520 may be installed from the beginning of the construction of the superconducting cable system, or a mounting portion for attaching these members to the superconducting cable system is provided so that the subsequent function when the cooling function is lost. You may install in. Alternatively, the short supply pipe 522 and the discharge pipe 524 and the second valve 526 are connected in advance to the vacuum heat insulation pipe 14, and this is used as a mounting portion to supply the remaining supply pipe 522 and discharge pipe 524 and liquid supply when the cooling function is lost. Source 520 or the like may be connected after the fact.

  Liquid source 520 (including pump 528) is at ground potential. On the other hand, the superconducting cable 100 is a room temperature insulation type, and since the vacuum heat insulating tube 14 becomes a high potential when used in a transmission line, an insulating joint 455 is provided between the vacuum heat insulating tube 14 and the liquid supply source 520. . In this example, an insulating joint 455 is provided between the open / close valves 526 and 526 and the liquid supply source 520 in the supply pipe 522 and the discharge pipe 524.

<System operation procedure>
(1) The point that the superconducting cable 100 is operated as a superconducting cable line at the normal time is the same as that of the second embodiment described above. At that time, the second valve 526 (open / close valves 526, 526) is closed.

  (2) When the cooling function is lost, as in the second embodiment, the superconducting cable 100 is disconnected from the power transmission system, the refrigerator 210 and the circulation mechanism (pump) of the cooling mechanism 200 are stopped, and the refrigerant is vaporized by the temperature rise. 20 is discharged from the circulation path. After the vaporized refrigerant 20 is discharged to the outside, the second valve 526 (open / close valves 526, 526) is opened, and water is introduced from the liquid supply source 520 into the heat insulation space of the vacuum heat insulation pipe. By filling the heat insulating space of the vacuum heat insulating tube 14 with water, the heat insulating performance of the vacuum heat insulating tube 14 is lowered, and the heat insulating tube 14 becomes a heat transfer tube.

  Further, until the heat insulating performance of the vacuum heat insulating tube 14 is lowered, the first blocking means 34 of one blocking means 33a is switched to the blocking state, and the connection on the conductor portion 10 side is blocked as in the second embodiment. The second blocking means 35 and the other blocking means 33b of one blocking means 33a are connected, and the external normal conducting member 16 side is connected. After the operation of the breaker is completed, the breaker on the system control system side is restored, and the power transmission by the conductor 10 is stopped, power is transmitted by the external normal conductive member 16, and the superconducting cable 100 is operated as a normal conductive cable line. To do.

  (3) After confirming that the heat insulation performance of the vacuum heat insulating tube 14 is reduced and the heat radiation of the conductor 10 is possible, the power transmission is temporarily stopped by the circuit breaker on the system control system side, and the superconducting cable 100 is disconnected from the power transmission system. Separate. Then, the first blocking means 34 of the one blocking means 33a is switched to the connected state, and the conductor 10 side and the external normal conducting member 16 side are connected to each of the blocking means 33a and 33b. After the operation of the shut-off means is completed, the circuit breaker on the system control system side is restored, and not only the external normal conductive member 16 but also the conductor portion 10 (internal normal conductive member) is used as a power transmission conductor for power transmission. At this time, by circulating a liquid in the heat insulation space of the vacuum heat insulation pipe 14 and cooling the heat insulation pipe 14, the temperature rise accompanying heat generation of the conductor 10 (internal normal conductive member) due to power transmission can be effectively suppressed. You can also.

<Effect>
Even in the superconducting cable system according to the third embodiment described above, as in the second embodiment, the heat insulation performance of the vacuum heat insulation tube 14 can be lowered when the cooling function is lost. Therefore, when the superconducting cable 100 is operated as a normal conductive cable line, even if the conductor 10 (internal normal conductive member) is also used as a power transmission conductor, the heat of the conductor 10 is dissipated and the temperature of the conductor 10 is The rise can be suppressed. In particular, by circulating water in the heat insulating space of the vacuum heat insulating tube 14, it is possible to effectively suppress the temperature rise accompanying heat generation of the conductor 10 (internal normal conductive member) during normal conductive cable operation.

  In the system of the third embodiment described above, the case where the liquid supply source 520 is connected to the heat insulation space of the vacuum heat insulation pipe 14 via the supply pipe 522 and the discharge pipe 524 and water is supplied to the heat insulation space of the vacuum heat insulation pipe 14 will be described. did. Further, the liquid supply source 520 may be connected to the heat insulation space of the vacuum heat insulation container 40 through the supply pipe 522 and the discharge pipe 524 in the same manner as the vacuum heat insulation pipe 14. With this configuration, liquid can be supplied also to the heat insulating space of the vacuum heat insulating container 40 to reduce the heat insulating performance of the heat insulating container 40, and heat generated by the conductor portion 10 in the heat insulating container 40 can be radiated.

(Embodiment 4)
Next, when the cooling function is lost, the refrigerant in the refrigerant flow path of the vacuum heat insulation pipe is vaporized, the vaporized refrigerant is filled in the heat insulation space of the vacuum heat insulation pipe, and the superconducting cable is operated as a normal conductive cable line. A superconducting cable system will be described with reference to FIG. Since the basic configuration of this system is the same as that of the second embodiment shown in FIG. 5, differences will be mainly described. This system includes a communication pipe 610, a pressure relief valve 620, a heat exchange unit 630, and a third valve 640 that allow the refrigerant flow path of the vacuum heat insulation pipe 14 to communicate with the heat insulation space.

[Communication pipe]
The communication pipe 610 is a pipe that connects the refrigerant flow path of the vacuum heat insulation pipe 14 and the heat insulation space. When the cooling function is lost, the cooling mechanism 200 does not operate normally, so the temperature of the refrigerant 20 rises and the liquid refrigerant 20 vaporizes. The communication pipe 610 introduces the vaporized refrigerant 20 from the refrigerant flow path of the vacuum heat insulation pipe 14 into the heat insulation space.

[Relief valve]
In the middle of the communication pipe 610 described above, a pressure release valve 620 is provided. When the cooling function is lost, the refrigerant 20 undergoes rapid volume expansion when it is vaporized, so that the pressure in the communication pipe 610 can be controlled to be excessive by opening the pressure release valve 620.

[Heat exchange part]
A heat exchange unit 630 is also provided in the middle of the communication pipe 610 described above. Even if the refrigerant 20 is vaporized, it is at a considerably low temperature. For example, in the case of liquid nitrogen, it is vaporized at about 77 K (-196 ° C.) at 1 atm to become nitrogen gas, but the vaporized nitrogen gas is also a cryogenic gas. If such a low-temperature vaporized refrigerant is immediately introduced into the heat insulating space of the vacuum heat insulating tube 14, the heat insulating tube 14 is rapidly cooled, and there is a possibility that other members close to the heat insulating tube 14 may be adversely affected. Therefore, the adverse effect of the above can be prevented by introducing the vaporized refrigerant into the heat insulating space after raising the temperature in the heat exchanging section 630. A specific configuration of the heat exchange unit 630 includes providing an appropriate container that can store the vaporized refrigerant 20 in the middle of the communication pipe 610. This container can increase the temperature of the vaporized refrigerant 20 more efficiently by increasing the contact area with the outside air by providing fins or the like. Alternatively, making the communication pipe 610 longer can also be used as the heat exchange unit 630.

[Third valve]
Further, a third valve 640 is provided in the middle of the communication pipe 610. In this example, in the middle of the communication pipe 610 between the heat exchange section 630 and the heat insulation space of the vacuum heat insulation pipe 14, and in the middle of the communication pipe 610 between the heat exchange section 630 and the refrigerant flow path of the vacuum heat insulation pipe 14. In addition, on-off valves 640 and 640 are respectively provided, and a third valve 640 is constituted by both the on-off valves. Since the heat insulating space of the vacuum heat insulating tube 14 is normally vacuum, when the third valve 640 is opened, the vaporized refrigerant 20 is introduced into the heat insulating space of the vacuum heat insulating tube 14. In this example, the opening / closing valve 640 is provided in the middle of the communication pipe 610 between the heat exchange unit 630 and the refrigerant flow path of the vacuum heat insulating pipe 14, but this opening / closing valve may be omitted.

  Also in the system of the fourth embodiment, as in the second embodiment, the communication pipe 610, the pressure release valve 620, the heat exchange unit 630, and the third valve 640 are installed from the beginning of the construction of the superconducting cable system. It doesn't matter whether it is installed in. For example, components such as the heat exchanging unit 630 may be installed from the beginning of the construction of the superconducting cable system, or a mounting part for attaching these members to the superconducting cable system is provided so that the ex post facto when the cooling function is lost. You may install in. Alternatively, a part of the communication pipe 610 and the third valve 640 are connected in advance to the vacuum heat insulating pipe 14, and this is used as a mounting part, so that the remaining communication pipe, heat exchange part 630, etc. can be used after the cooling function is lost. You may connect.

  Since the heat exchanging unit 630 is at the ground potential, an insulating joint 455 is provided between the vacuum heat insulating tube 14 and the heat exchanging unit 630 as in the second embodiment. In this example, an insulating joint 455 is provided between the open / close valves 640 and 640 and the heat exchange unit 630 in the communication pipe 610.

<System operation procedure>
(1) The point that the superconducting cable 100 is operated as a superconducting cable line at the normal time is the same as that of the second embodiment described above. At that time, the third valve 640 is closed.

  (2) When the cooling function is lost, as in the second embodiment, the superconducting cable 100 is disconnected from the power transmission system, the refrigerator 210 and the circulation mechanism (pump) of the cooling mechanism 200 are stopped, and the temperature of the refrigerant 20 increases. To do. When the liquid refrigerant 20 is heated and vaporized, the third valve 640 is opened, and the vaporized refrigerant is introduced from the refrigerant flow path of the vacuum heat insulation pipe 14 into the heat insulation space of the vacuum heat insulation pipe 14 via the communication pipe 610. At that time, if necessary, the pressure relief valve 620 is opened, and control is performed so that the pressure in the communication pipe 610 becomes excessive. The vaporized refrigerant 20 is once introduced into the heat exchange unit 630 through the communication pipe 610, where the temperature is raised. The heated vaporized refrigerant is introduced into the heat insulating space. By introducing the vaporized refrigerant, the heat insulating performance of the vacuum heat insulating tube 14 is lowered, and the heat insulating tube 14 becomes a heat transfer tube.

  Further, until the heat insulating performance of the vacuum heat insulating tube 14 is lowered, the first blocking means 34 of one blocking means 33a is switched to the blocking state, and the connection on the conductor portion 10 side is blocked as in the second embodiment. The second blocking means 35 and the other blocking means 33b of one blocking means 33a are connected, and the external normal conducting member 16 side is connected. After the operation of the breaker is completed, the breaker on the system control system side is restored, and the power transmission by the conductor 10 is stopped, power is transmitted by the external normal conductive member 16, and the superconducting cable 100 is operated as a normal conductive cable line. To do.

  (3) After confirming that the heat insulation performance of the vacuum heat insulating tube 14 is reduced and the heat radiation of the conductor 10 is possible, the power transmission is temporarily stopped by the circuit breaker on the system control system side, and the superconducting cable 100 is disconnected from the power transmission system. Separate. Then, the first blocking means 34 of the one blocking means 33a is switched to the connected state, and the conductor 10 side and the external normal conducting member 16 side are connected to each of the blocking means 33a and 33b. After the operation of the shut-off means is completed, the circuit breaker on the system control system side is restored, and not only the external normal conductive member 16 but also the conductor portion 10 (internal normal conductive member) is used as a power transmission conductor for power transmission.

<Effect>
In the superconducting cable system according to the fourth embodiment described above, as in the second embodiment, the heat insulation performance of the vacuum heat insulating tube 14 can be lowered when the cooling function is lost. Therefore, when the superconducting cable 100 is operated as a normal conductive cable line, even if the conductor 10 (internal normal conductive member) is also used as a power transmission conductor, the heat of the conductor 10 is dissipated and the temperature of the conductor 10 is The rise can be suppressed. In particular, in order to introduce the vaporized refrigerant 20 in the refrigerant flow path of the vacuum heat insulating tube 14 into the heat insulating space of the vacuum heat insulating tube 14 as a heat conductive material, a heat conductive material that fills the heat insulating space separately from the refrigerant 20 is prepared. There is no need to keep it. Further, by providing the heat radiation valve 620, it is possible to prevent the inside of the communication pipe 610 from becoming an excessive pressure due to the vaporized refrigerant 20. Furthermore, by providing the heat exchanging unit 630, it is possible to prevent the vaporized refrigerant 20 from being introduced into the heat insulation space at an excessively low temperature, and to avoid adverse effects on members adjacent to the heat insulation pipe.

  In the system of the fourth embodiment described above, the case where the refrigerant flow path of the vacuum heat insulating tube 14 and the heat insulating space are communicated via the communication tube 610 and the vaporized refrigerant is filled in the heat insulating space of the vacuum heat insulating tube 14 has been described. Further, similarly to the vacuum heat insulation pipe 14, the refrigerant flow path and the heat insulation space of the vacuum heat insulation container 40 may be communicated with the heat insulation space of the vacuum heat insulation container 40 via the communication pipe 610. With such a configuration, the heat insulation performance of the heat insulation container 40 can be reduced by filling the heat insulation space of the vacuum heat insulation container 40 with the vaporized refrigerant, and the heat generated by the conductor 10 in the heat insulation container 40 can be radiated. .

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention. For example, the arrangement and form of the first current lead, the second current lead, and the interruption means (first interruption means and second interruption means) may be changed as appropriate. Moreover, in each embodiment of Embodiment 2-4 mentioned above, although the structure for filling a heat insulation material into the heat insulation space at the time of a cooling function loss is provided individually, even if it utilizes, combining these each structure Good. In addition, the former of the superconducting cable may be formed of a nonconductive material.

  The superconducting cable system of the present invention can be used for power transmission as a superconducting cable line during normal times, and can be used for power transmission as a normal conducting cable line when the cooling function is lost.

100,101,102 Superconducting cable (room temperature insulated superconducting cable)
10 Conductor section
11 Former 12 Superconducting conductor layer 13 Protective layer
14 Heat insulation pipe (vacuum heat insulation pipe)
14a Inner pipe 14b Outer pipe
15 Main electrical insulation layer
16 External normal conductive member
17 Tubular support
20 Refrigerant
30 Terminal conductor
31 First current lead 32 Second current lead
33a, 33b Blocking means
34 First blocking means 35 Second blocking means
36 Thermal insulation
40 Insulated container 42 Mating part
50 Terminal insulation 51 Steel pipe
53 Branch refrigerant pipe 55 Insulation joint
60 Connecting conductors for normal electrical power equipment
150a, 150b terminal
200 Cooling mechanism 210 Refrigerator 215 Cooling tower
300 Refrigerant pipe
410 Vacuum pump 420 Gas supply source 440 First valve
440A, 440B Open / close valve 450 Communication pipe 450L, 450R Branch pipe
460 Compressor 470 Open / close valve
480 Pressure filling mechanism 480V open / close valve
455 Insulation joint
520 Liquid source 522 Supply pipe 524 Discharge pipe
526 Second valve (open / close valve) 528 Pump
610 Communication pipe 620 Pressure relief valve 630 Heat exchanger 640 Third valve

Claims (8)

A superconducting cable system including a superconducting cable provided at both ends of the superconducting cable and having a terminal conductor for connecting to a normal conducting power device through a current lead, and a cooling mechanism for the refrigerant,
The superconducting cable is
A conductor portion having a superconducting conductor layer;
A heat-insulating pipe through which the refrigerant flows, containing the conductor portion and cooling the superconducting conductor layer;
A main electrical insulating layer provided outside the heat insulating tube;
A room temperature insulated superconducting cable comprising an external normal conducting member formed between the heat insulating tube and the main electrical insulation layer,
The both terminal conductor portions are
A first current lead connecting the conductor and the power device;
A second current lead connecting the external normal conducting member and the power device;
A blocking means for blocking the connection between the conductor part and the external normal conducting member and the power device,
The blocking means in the at least one terminal conductor portion is:
A superconducting cable system, comprising: a first blocking means for blocking the connection on the conductor portion side; and a second blocking means for blocking the connection on the external normal conducting member side.   The said one interruption | blocking means WHEREIN: When the said conductor part side is made into the interruption | blocking state by said 1st interruption | blocking means, said conductor part side is made into a connection state in said other interruption | blocking means. Superconducting cable system. The heat insulation pipe of the superconducting cable is a vacuum heat insulation pipe having a heat insulation space,
When the cooling mechanism is inoperable and the superconducting conductor layer cannot be maintained in a superconducting state, at least when the cooling function is lost, a filling means attaching portion is provided for attaching at least a filling means for filling a heat conductive material in the heat insulating space of the vacuum heat insulating tube. The superconducting cable system according to claim 1 or 2. The filling means
A gas supply source containing a gas to be the heat conducting material;
The superconducting cable system according to claim 3, further comprising a first valve that supplies and stops the gas from the gas supply source to the heat insulation space. Furthermore, a vacuum pump for evacuating the heat insulation space is provided,
5. The superconducting cable system according to claim 4, wherein the first valve is an open / close valve that selectively connects the gas supply source and the vacuum pump to the heat insulation space. The filling means
A liquid supply source for storing a liquid serving as the heat conductive material;
A supply pipe for supplying the liquid from the liquid supply source to the heat insulation space;
A discharge pipe for discharging the liquid from the heat insulation space;
A second valve for communicating and blocking each of the supply pipe and the discharge pipe;
The superconducting cable system according to any one of claims 3 to 5, further comprising: a pumping unit configured to circulate the liquid using the supply pipe, the heat insulating space, and the discharge pipe as a flow path. The filling means
A communication pipe for communicating the refrigerant flow path in the vacuum heat insulation pipe and the heat insulation space of the vacuum heat insulation pipe;
The superconducting cable system according to any one of claims 3 to 6, further comprising a third valve for communicating and blocking the communication pipe.   At least one of a pressure release valve that releases the pressure of the refrigerant vaporized when the cooling function is lost and a heat exchange unit that increases the temperature of the vaporized refrigerant is provided in the middle of the communication pipe. The superconducting cable system according to claim 7.

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