JP4941044B2 - Superconducting cable terminal structure - Google Patents

Description

  The present invention relates to a terminal structure of a superconducting cable arranged in a state where a plurality of cable cores are twisted together inside a heat insulating tube.

  As a superconducting cable, for example, a cable using a superconducting conductor (superconducting wire) made of a Bi-based high-temperature superconducting tape wire or the like is known. In this type of superconducting cable, a cable core including a former, a superconducting conductor layer, an electrical insulating layer, a shield layer, and a protective layer is accommodated in the order of the center from the center of a heat insulating pipe made of a double metal corrugated pipe.

  In this heat insulating tube, a space between the inner tube and the outer tube is evacuated, and a vacuum heat insulating material is disposed in this space (see, for example, Patent Document 1). In the superconducting cable, during operation of the cable, a liquid refrigerant such as liquid nitrogen is circulated inside the inner tube of the heat insulating tube to cool the cable core housed in the inner tube to a critical temperature or lower.

  By the way, like the superconducting cable currently disclosed by patent document 1, when the several cable core twisted in the heat insulation pipe | tube is accommodated, when a cable core is cooled with liquid nitrogen, a cable core will be compared with a normal temperature state. Shrink. However, since both ends of the cable core are fixed at the intermediate connection portion and the terminal connection portion, when the twisted cable core is thermally contracted, the twist is tightened, and the cable core is subjected to axial stress (tensile stress), The superconducting conductor may be damaged.

  Therefore, for example, as disclosed in Patent Document 1, the superconducting cable has a spacer interposed between the cable cores when twisting a plurality of cable cores, and the twisted cable cores are arranged in the inner pipe of the heat insulating pipe. Before being housed, the spacer is removed, so that the cable core twist is loosened, and the shrinkage is absorbed by the slack of the twist.

JP 2002-216555 A

  By the way, the superconducting cable is transported or stored while being wound around a dedicated drum at the time of manufacture and shipment. In particular, during cable manufacture, the cable is wound around the drum for each step, and the cable is pulled out from the drum in the next step.

  When the cable is wound around the drum, the cable wound around the drum is curved, so that the cable core housed inside the inner tube is in a compressed state on the center side of the inner tube winding, Will be pulled.

  Therefore, during manufacturing, if the end of each cable core is not fixed to the heat insulating pipe, the cable core disposed in the inner pipe will be pivoted inside the inner pipe while being wound around the drum and pulled out repeatedly. There is a risk that the amount of twist in the cable core will be reduced due to displacement in the direction. In particular, in the case of a long cable, since the weight of the cable increases, the frictional resistance increases, and the loose state of the twist is difficult to return to the original state.

  As a result, if the amount of loosening of the twist becomes insufficient when the cable is laid, when the cable core is thermally contracted during cable operation, there is a possibility that the loosening of the twist is insufficient and the cable core may be damaged.

  As described above, the present invention provides a superconducting cable that can maintain the looseness of the twist of the cable core in the heat insulating tube even when the operation of winding or pulling the cable around the drum is repeated during the manufacture of the superconducting cable. An object of the present invention is to provide a terminal structure.

  The terminal structure of the superconducting cable of the present invention is a flat structure in which a heat insulating tube is compressed into a flat shape together with a plurality of cable cores at the end of the superconducting cable arranged in a state where a plurality of cable cores are twisted inside the heat insulating tube. A portion is formed.

  The flat part of this heat insulation pipe is formed by compressing the ends of the heat insulation pipes that are twisted together and housed in a state where a plurality of cable cores are loosened together with the cable core to form a flat part. Thus, the ends of the plurality of cable cores are fixed. That is, even if the cable core tries to extend in the axial direction, the extension force can be received by the heat insulating tube compressed flatly to prevent the cable core from moving in the axial direction.

  As a result, by simply forming a flat portion in the heat insulation pipe, each cable core does not move in the axial direction with respect to the heat insulation pipe, so that it is possible to prevent the twist looseness from being reduced, and the cable core twist looseness. Can be maintained.

  The flat portion can be formed by compression molding the inner tube when the heat insulating tube is formed only by the inner tube during the manufacturing process, and the outer tube is formed outside the inner tube. When these are arranged, the inner tube and the outer tube can be compression-molded to form a flat portion.

  Further, the flat part is preferably compressed and then cut to align the ends. For example, the end part of the heat insulation pipe | tube which accommodated the cable core is cut | disconnected simultaneously with compressing with a hydraulic cutter.

  By the way, conventionally, the heat insulation pipe | tube which comprises a superconducting cable is comprised by the double stainless steel corrugated pipe | tube as disclosed by patent document 1. FIG. The corrugated tube is usually formed by welding a stainless steel plate into a pipe shape and then performing corrugation.

  However, if there are weld cracks or pinholes in the welded part of the corrugated pipe, the superconducting cable will cause the refrigerant to leak from the inside of the inner pipe of the heat insulating pipe or the vacuum deterioration of the heat insulating pipe will cause the cable core to be in a superconducting state. Cannot be maintained.

  Therefore, in order to inspect for the presence or absence of weld cracks and pinholes, a pressure test and a minute leak test of the heat insulation pipe are usually performed over the entire length of the cable during cable manufacture.

  The pressure test is a test for confirming whether or not the pressure inside the inner pipe of the heat insulating pipe during cable operation can withstand a set pressure (for example, 0.6 MPa). In this pressure test, the end of the inner tube containing the cable core is sealed with a lid, and high-pressure gas (eg, nitrogen, air, etc.) is injected into the inner tube through a port attached to the cable end. Enclose and confirm that it can withstand the specified test pressure.

  In addition, the micro leak test is generally performed using a highly sensitive helium gas. And it is necessary to perform a leak test on each of the inner tube and the outer tube. Examples of the minute leak test include a vacuum method, a vacuum volume method, and a pressurization method.

  In any of the leak tests, the leak test of the outer pipe is performed after the leak test of the inner pipe. When performing a leak test on an inner tube that houses a cable core, the leak test is performed by sealing both ends of the inner tube with lids having ports. Further, when conducting a leak test of the outer tube, the both end openings formed between the inner tube and the outer tube are sealed with a lid.

  However, if the end of the superconducting cable is flattened to form a flattened part in order to maintain the looseness of the cable core twist, the length of the flattened part of the cable end becomes larger than the diameter of the heat insulating tube. End up. As a result, a cylindrical lid having the same inner diameter as the outer diameter of the heat insulating tube of the cable cannot be attached as it is.

  Accordingly, in the terminal structure of the superconducting cable according to the present invention, when a lid is attached to the end of the cable, the lid that covers the flat portion and seals the end of the insulated tube is fixed to the end of the insulated tube. . This lid can be configured to have a large-diameter portion that covers the flat portion of the heat insulating tube and a small-diameter portion that is fitted to the outer surface of the heat-insulating tube following the large-diameter portion. The lid is closed at the end portion in the axial direction of the large-diameter portion, and the seal portion is formed on the entire outer periphery of the small-diameter portion and the entire outer periphery near the opening of the small-diameter portion in the heat insulating tube. The lid is preferably fixed to the heat insulating tube in an airtight manner.

  In addition, since a heat insulation pipe | tube and a cover body are normally formed with a metal, it is preferable that a seal part forms a seal part with metals, such as solder and lead. In particular, in consideration of securing the seal area, it is preferable to perform lead processing.

  Thus, even if the cable end becomes larger than the outer diameter of the heat insulating tube by forming a flat part for holding the slack of the twist of the cable core at the end of the superconducting cable, the lid is changed to the small diameter part. By setting it as the structure which has a large diameter part, the airtightness between a cover body and a heat insulation pipe | tube can be made favorable, covering a flat part completely.

  The present invention can form a seal portion with a cable having a large tip shape and a cover body in a state where the opening of the cover body is in close contact with the heat insulating tube, so that airtightness and bonding strength between the cover body and the heat insulating tube can be formed. Thus, it is possible to provide a terminal structure of a superconducting cable that sufficiently satisfies

  As a result, by attaching the lid to the end portion of the cable having the flat portion, it is possible to easily and reliably perform the pressure test and the leak test of the heat insulation pipe while maintaining the slack of the twist of the cable core.

  Further, the lid has a large-diameter cylindrical member with one end that becomes a large-diameter portion closed, a small-diameter cylindrical member that becomes a small-diameter portion, and a large-diameter cylindrical member and a small-diameter cylindrical member that are airtightly connected to each other. It is preferable to provide a ring-shaped connecting portion formed integrally with the end portion of the member.

  In this case, it is preferable that the small-diameter cylindrical member and the connection portion are configured by mutually joining half-cracked members obtained by half-splitting the integrated cylindrical member. Then, in a state where the small diameter cylindrical member is formed in a cylindrical shape, the end portion of the connection portion and the open end portion of the large diameter cylindrical member are joined to constitute a lid.

  Since the lid is configured by combining the large-diameter cylindrical member and the small-diameter cylindrical member formed with the connection portion, the lid can be easily assembled to the heat insulating tube while improving airtightness.

  Specifically, since the half-cracked members are welded in a state of covering the inner tube on the axially inner side from the flat portion to form a small-diameter cylindrical member having a connection portion, the small-diameter cylindrical member is used as a heat insulating tube. It can be easily attached in a close contact state. And in the state which accommodated the flat part of the inner pipe in the large diameter cylindrical member, by welding this large diameter cylindrical member and the connection part formed in the small diameter cylindrical member, the small diameter cylindrical member and the large diameter cylindrical member Can be easily configured. In this way, by welding and joining the members constituting the lid, the lid can be easily assembled to the superconducting cable, and the strength of the joint between the lid and the heat insulating tube can withstand high pressure. It can be secured.

  In addition, the lid body forms a half-cracked member in which the cylindrical body integrated with the large-diameter portion and the small-diameter portion is half-cracked, and in the state where these half-cracked members are arranged around the heat insulating tube, It is also possible to attach the lid to the heat insulating tube by joining the half-cracked members together by welding.

  Further, the seal portion is formed by performing a lead processing near the small diameter portion of the lid and the opening of the small diameter portion of the heat insulating pipe, and a reinforcing portion made of a synthetic resin is provided around the seal portion (lead work portion). Preferably it is formed.

  After fixing the insulation pipe and the small-diameter part by lead processing, the reinforcement part is formed around the lead work part to reinforce the lead work part, thereby improving the joint strength between the heat insulation pipe and the lid Can be made. By forming this reinforcing portion, even in a pressure test at a high pressure, the airtightness due to the lead work portion can be reliably maintained, and the pressure test of the heat insulating pipe can be reliably performed.

  In addition, during the pressure test at high pressure, even if an extension force is generated in the heat insulation pipe and the lead work part tries to extend mechanically, this reinforcing part prevents the lead work part from extending, and the superconducting cable Can be prevented from being damaged.

  The reinforcing part is preferably formed by impregnating a sheet member formed of glass fiber with an epoxy resin to form a prepreg, and winding the resin-impregnated sheet around a lead work portion to thermally cure the epoxy resin. Moreover, you may use fiber reinforced resin, such as a thermosetting resin which has glass fiber, as a synthetic resin which forms a reinforcement part.

  In the terminal structure of the superconducting cable according to the present invention, the end portion of the heat insulating tube has a flat portion formed by being compressed into a flat shape together with the plurality of cable cores. The cable core does not move in the axial direction with respect to the heat insulating tube. As a result, the flat part can prevent the cable core twist from becoming less slack, so that the cable core twist slack can be maintained even when the cable is repeatedly wound and pulled out. Can do.

  Hereinafter, embodiments of the terminal structure of the superconducting cable of the present invention will be described. In the present embodiment, a cable terminal structure in a state where only the inner pipe of the heat insulation pipe is formed around the cable core in the superconducting cable in which the three cable cores are housed in the heat insulation pipe will be described.

  As shown in FIG. 4, the completed state of the superconducting cable 100 according to the present embodiment includes a three-core cable core 10 and a heat insulating tube 20 that houses the cable core 10. Each cable core 10 includes a former 11, a superconducting conductor layer 12, an insulating layer 13, a superconducting shield layer 14, and a protective layer 15 in order from the center.

  The superconducting conductor layer 12 is formed by winding a superconducting wire on the former 11 in a spiral manner in multiple layers. This superconducting wire is formed by embedding a number of Bi2223 superconducting filaments in a silver matrix. The insulating layer 13 is formed by winding semi-synthetic paper obtained by bonding insulating paper and a polypropylene film around the superconducting conductor layer 12. The superconducting shield layer 14 is formed by winding a superconducting wire similar to that used for the superconducting conductor layer 12 around the insulating layer 13 in multiple layers.

  On the other hand, the heat insulating tube 20 is a double tube including an inner tube 21 and an outer tube 22, and a vacuum heat insulating layer is formed between the inner and outer tubes 21 and 22. Both the inner tube 21 and the outer tube 22 are corrugated tubes. A so-called super insulation (trade name) in which a plastic mesh and a metal foil are laminated is disposed in the vacuum heat insulating layer. Further, an anticorrosion layer 23 and a protective coating layer (not shown) are sequentially formed outside the outer tube 22.

  The inside of the inner pipe 21 in the heat insulating pipe 20 serves as a refrigerant flow path that is filled with a refrigerant such as liquid nitrogen that cools the cable core 10.

  In the present embodiment, the three-core cable core 10 having the above-described configuration is accommodated inside the inner tube 21 in a state where the twist is loosened. In the present embodiment, a terminal structure of a superconducting cable when the inner tube 21 covers the three-core cable core 10 will be described. The formation of the twisted slack of the cable core 10 can be performed by a known method.

  As shown in FIG. 1, the terminal structure of the superconducting cable according to the present embodiment is formed by compressing the end portion of the inner tube 21 of the heat insulating tube 20 into a flat shape together with a plurality of cable cores 10 to form a flat portion 24. Yes.

  The flat portion 24 is formed at the end portion of the inner tube 21 by compressing and cutting the end portion of the inner tube 21 of the heat insulating tube 20 housing the cable core 10 with a hydraulic cutter. By forming the flat portion 24 at the end of the inner tube 21, even if the cable core 10 is about to extend in the axial direction, the extension force is received by the flat compressed portion of the inner tube 21, and the cable core 10 movements in the axial direction can be prevented.

  As described above, since the flat portion 24 is formed at the end of the inner tube 21, the cable core 10 is prevented from moving in the axial direction with respect to the inner tube 21, and the twist slack is prevented from being reduced. Therefore, the state of twisted looseness of the cable core 10 can be maintained.

  Further, in the present embodiment, after the flat portion 24 is formed at the end portion of the superconducting cable 100, the end portion of the inner tube 21 of the heat insulating tube 20 is covered with the flat portion 24 as shown in FIG. The lid 3 that seals the end of 21 is fixed, and the pressure test and helium leak test of the inner tube 21 are performed.

  The lid 3 includes a large-diameter portion 31 that covers the flat portion 24 of the inner tube 21, and a small-diameter portion 32 that is fitted to the outer surface of the inner tube 21 following the large-diameter portion 31.

  The specific configuration of the lid 3 will be described. The lid 3 includes a large-diameter cylindrical member 4 that becomes the large-diameter portion 31 and a small-diameter cylindrical member 5 that becomes the small-diameter portion 32.

  The large-diameter cylindrical member 4 is a cylinder whose end in the axial direction is closed, and the inner diameter of the cylindrical portion of the large-diameter cylindrical member 4 is larger than the maximum length of the flat portion 24. The flat portion 24 of the cable 100 is accommodated in the large-diameter cylindrical member 4.

  Further, a ring-shaped locking portion 41 is projected from the center in the axial direction on the outer peripheral surface of the cylindrical portion of the large-diameter cylindrical member 4. A wire is inserted through the locking portion 41, and the wire is fixed to the drum while being inserted through the locking portion 41 when the cable 100 is wound around the drum. By fixing the wire to the drum, the cable wound around the drum is prevented from extending in the axial direction.

  The sealing surface that seals one end of the cylindrical portion of the large-diameter cylindrical member 4 includes a pressure test port 42 for injecting high-pressure gas into the inner tube 21 during the pressure test, and an inner tube 21 during the leak test. A leak test port 43 for injecting helium gas or evacuating the inside of the inner tube 21 is provided.

  The small-diameter cylindrical member 5 is integrally formed with a ring-shaped connection portion 33 at the connection side end with the large-diameter cylindrical member 4. The small-diameter cylindrical member 5 having the connecting portion 33 is composed of two half-cracked members 6. This half-cracked member 6 includes a half-cracked cylindrical member 61 that is a half-cracked cylindrical member having an inner diameter that is the same as the outer diameter of the inner tube 21, and an inner diameter that is the same as the outer diameter of the half-cracked cylindrical member 61. The arc member 62 is formed by welding a ring member 62 having a half-cracked ring member having an outer diameter substantially the same as the outer diameter of the large-diameter cylindrical member 4. In the present embodiment, the arc members 62 are joined together to form the connecting portion 33.

  The arc member 62 and the half-cracked cylindrical member 61 are joined in a state where the inner surface of the arc member 62 is in contact with the outer peripheral surface of the axial end portion of the half-cracked cylindrical member 61. This is performed by welding the overlapping portion of 61 from the outside of the half-cracked cylindrical member 61.

  Then, two half-cracked members 6 in which the arc member 62 and the half-cracked cylindrical member 61 are joined and integrated are prepared, and the end portions in the circumferential direction of the half-cracked members 6 are attached to each other and joined by welding. A small diameter cylindrical member 5 having a portion 33 is formed.

  Then, the end face of the connecting portion 33 and the opening end face of the large-diameter cylindrical member 4 are abutted, and the connecting portion 33 and the large-diameter cylindrical member 4 are joined and integrated by welding. As described above, the connecting portion 33 and the large-diameter cylindrical member 4 are joined and integrated, whereby the small-diameter cylindrical member 5 and the large-diameter cylindrical member 4 are integrated to form the lid 3.

  In the present embodiment, in order to fix the lid 3 to the inner tube 21 in an airtight manner, the entire outer peripheral surface of the small diameter cylindrical member 5 and the entire outer peripheral surface of the inner tube 21 near the opening of the small diameter cylindrical member 5 are covered. In this way, lead processing 7 is formed as a seal portion by performing lead processing.

  Furthermore, in this embodiment, a reinforcing portion 8 is formed around the lead work portion 7. The reinforcing portion 8 is formed by impregnating a sheet member formed of glass fiber with an epoxy resin to form a prepreg, and winding the resin-impregnated sheet around the lead work portion 7 to thermally cure the epoxy resin. By forming the reinforcing portion 8, the end portion of the cable 100 has a structure that can withstand a high pressure test.

  Next, an assembling method of each part of the lid 3 for attaching the lid 3 to the end of the superconducting cable 100 having the flat portion 24 will be described with reference to FIG.

  First, the end portion of the cable 100 in which the cable core 10 is housed inside the inner tube 21 is compressed and cut to form a flat portion 24, and the end portions of the three-core cable core 10 are flatly compressed. The state is fixed with the inner tube 21.

  And about the small diameter cylindrical member 5 which comprises the cover body 3, two half crack members 6 which joined the half crack cylindrical member 61 and the circular arc member 62 first by welding are formed first. Next, each half-cracked member 6 is in close contact with the outer peripheral surface of the inner tube 21 that is on the axially inner side of the position where the flat portion 24 of the inner tube 21 is formed. They are joined together by welding. By this joining, the two half crack members 6 are integrated with each other to form a small-diameter cylindrical member 5 having a connecting portion 33, and the small-diameter cylindrical member 5 and the connecting portion 33 are fitted around the inner tube 21. become.

  Then, the large-diameter cylindrical member 4 is placed on the end portion of the cable 100 so as to cover the flat portion 24. The large-diameter cylindrical member 4 and the small-diameter cylindrical member 5 are integrated together by welding in the circumferential direction in a state where the opening end surface of the large-diameter cylindrical member 4 and the end surface of the connecting portion 33 in the small-diameter cylindrical member 5 are in contact with each other. To form the lid 3.

  The outer circumferential surface of the small-diameter cylindrical member 5 in the lid 3 and the entire outer circumferential surface of the inner tube 21 near the opening of the small-diameter cylindrical member 5 are subjected to lead processing so that the small-diameter cylindrical member starts from the inner tube 21. A lead work portion 7 having a predetermined thickness up to 5 is formed. By forming the lead work portion 7, the space between the small-diameter cylindrical member 5 of the lid 3 and the inner tube 21 is made airtight.

  After the leadwork portion 7 is formed, a glass sheet impregnated with an epoxy resin is wound around the leadwork portion 7 and thermally cured to form the reinforcing portion 8. By forming the reinforcing portion 8, the lid 3 is attached to the end portion of the cable 100 in an airtight state.

  Then, with the lid 3 attached to the end of the cable 100, the cable 100 is wound around the drum, and the pressure test and the leak test of the inner tube 21 are performed while the cable 100 is wound around the drum.

  When performing the pressure test, at the outer end of the winding of the cable 100 wound around the drum, the wire is inserted into the locking portion 41 formed on the lid 3 provided at this end, and the wire is inserted into the drum. Fix and do pressure test.

  As described above, in the terminal structure of the superconducting cable according to the present embodiment, the end portion of the inner tube 21 of the heat insulating tube 20 in which the three-core cable core 10 is twisted and housed in a slack state is connected to the cable. The flat portion 24 is formed by being compressed together with the core 10 so as to be flat. With the flat portion 24 of the inner tube 21, the end portions of the three-core cable core 10 are fixed to the inner tube 21.

  As a result, even if the cable core tries to extend in the axial direction, the extension force can be received by the heat insulating tube compressed flatly to prevent the cable core from moving in the axial direction.

  That is, only by forming the flat portion 24 in the inner tube 21, each cable core 10 is prevented from moving in the axial direction with respect to the inner tube 21, so that it is possible to prevent the twist slack from being reduced. It is possible to maintain the state of slack in the twist.

  Further, in the present embodiment, in order to inspect whether there is a weld crack or a pinhole in the welded portion of the inner tube 21, a lid 3 is attached to the end of the inner tube 21, and a pressure test and a leak test are performed. Do.

  In the pressure test, the end of the inner tube 21 in which the cable core 10 is housed is sealed with the lid 3, and a high-pressure gas (for example, nitrogen) is introduced into the inner tube 21 from the pressure test port 42 of the lid 3. , Air, etc.).

  In addition, in the leak test, a sensitive helium gas is injected into the inner tube 21 from the leak test port 43 of the lid 3 with respect to the inner tube 21 whose end is sealed with the lid 3. This is performed by detecting leakage of helium gas from the outer surface of the inner tube 21.

  In the present embodiment, since the lid 3 is attached so as to fit in an airtight manner to the end of the inner tube 21 while covering the flat portion 24, the lid body is completely covered with the flat portion 24. The airtightness between 3 and the inner tube 21 can be improved.

  That is, the lead work can be performed with the cable 100 and the lid 3 having a large tip shape in a state where the opening of the small-diameter cylindrical member 5 in the lid 3 is in close contact with the outer surface of the inner tube 21. It is possible to provide a terminal structure of a superconducting cable that sufficiently satisfies the hermeticity and bonding strength between the inner tube 21 and the inner tube 21.

  As a result, by attaching the lid 3 to the end of the cable 100 having the flat portion 24, it is possible to easily and reliably perform the pressure test and the leak test of the inner tube 21 while maintaining the looseness of the twist of the cable core 10. It can be carried out.

  Since the lid 3 is configured by combining the large-diameter cylindrical member 4 to be the large-diameter portion 31 and the small-diameter cylindrical member 5 having the connection portion 33 formed by joining the half-cracked member 6, Of course, airtightness can be improved, and the lid 3 can be easily assembled to the inner tube 21.

  That is, in the present embodiment, even if the flat portion 24 having a width larger than the outer diameter of the inner tube 21 is formed at the end portion of the cable 100, the half-cracked members 6 are arranged in the axial direction more than the flat portion 24. Since the small-diameter cylindrical member 5 is formed by welding in a state of covering the inner tube 21 on the side, the small-diameter cylindrical member 5 can be easily attached while being in close contact with the inner tube 21. Then, in a state where the flat portion 24 of the inner tube 21 is housed in the large diameter cylindrical member 4, the small diameter cylindrical member 5 is welded to the small diameter cylindrical member 5 by welding the connecting portion 33 formed on the large diameter cylindrical member 4. The lid 3 in which the member 5 and the large-diameter cylindrical member 4 are integrated can be easily configured. In this way, by welding and joining the members constituting the lid 3, the lid 3 and the inner tube 21 can be joined at a high pressure while the lid 3 can be easily assembled to the superconducting cable 100. Can withstand the strength.

  Furthermore, since the reinforcing portion 8 is formed on the outer periphery of the leadwork portion 7 to reinforce the leadwork portion 7, the bonding strength between the inner tube 21 and the lid 3 can be improved. By forming the reinforcing portion 8, even in a pressure test at a high pressure, the airtightness by the lead work portion can be reliably maintained, and the pressure test of the inner tube 21 can be reliably performed.

  Moreover, during the pressure test at high pressure, even if an extension force is generated in the inner pipe 21 and the lead work part 7 tries to extend mechanically, this reinforcement part 8 prevents the lead work part 7 from extending. Thus, the superconducting cable can be prevented from being damaged.

  Furthermore, when the pressure test is performed with the cable 100 wound around the drum, both ends of the inner tube 21 are sealed with the lid 3, and high pressure is applied to the inside thereof, so that a surface pressure is applied to the sealing surface of the lid. The cable 100 generates a force that extends in the axial direction.

  In the present embodiment, the wire is inserted through the locking portion 41 formed on the large-diameter cylindrical member 4 of the lid 3 and the wire is fixed to the drum. The extension can be suppressed by a wire that is inserted into the locking portion 41. As a result, the extension of the cable can be prevented by the wire inserted through the engaging portion 41, so that the mechanical margin of the lead work portion 7 and the reinforcing portion 8 can be increased. In addition, it is possible to prevent the slack in twisting of the cable core 10 from decreasing with the extension of the inner tube 21 due to the cable extension during the pressurization test.

  By the way, when the pressure test and the leak test are performed on the inner pipe 21, the specifications of the pipes connected to the devices connected in the respective tests are different. Therefore, when only one port is formed on the lid, the connector to connect to the port does not fit, or the lid is exchanged according to the connector, and the connection work between the port and the connector is complicated. When the lid is replaced, problems such as a decrease in the reliability of the airtight state between the lid and the heat insulating tube occur.

  In the present embodiment, since the pressure test port 42 and the leak test port 43 are provided on the sealing surface of the large-diameter cylindrical member 4 of the lid 3, the lid 3 is tested even if the piping specifications are different. Therefore, it is not necessary to perform the replacement work every time the difference is made, and the reliability when the lid 3 is assembled to the inner tube 21 is improved. As a result, the work time for performing each test can be shortened, and each test can be performed efficiently without fail.

  In the present embodiment, the flat portion 24 is formed on the cable formed of only the inner tube 21, but the flat portion is formed on the cable in a state where the outer tube is disposed outside the inner tube. You can also. Even when the flat portion is formed by the inner tube and the outer tube, the lid having the large diameter portion and the small diameter portion described above can be attached to the end portion of the cable so as to cover the outer tube.

  Further, the terminal structure of the superconducting cable of the present invention may be employed for any superconducting cable for DC power transmission or AC power transmission.

  Furthermore, the terminal structure of the superconducting cable of the present invention is not limited to the above-described embodiment, and the scope of the present invention is not limited to the above-described embodiment.

  The terminal structure of the superconducting cable of the present invention can be suitably used when performing a pressure test or a leak test on the cable.

It is a terminal structure of the superconducting cable of the present invention, and is a perspective view showing a state where a flat portion is formed at the end of the superconducting cable. It is sectional drawing which shows the state which attached the cover body to the edge part of the superconducting cable in which the flat part was formed in the edge part. It is explanatory drawing for demonstrating the assembly | attachment of each member of the cover body attached to the edge part of a superconducting cable. It is radial direction sectional drawing of a superconducting cable.

Explanation of symbols

100 superconducting cable
10 Cable core
11 Former 12 Superconducting conductor layer 13 Insulating layer
14 Superconducting shield layer 15 Protective layer
20 Heat insulation pipe 21 Inner pipe 22 Outer pipe 23 Anticorrosion layer
24 Flat part
3 Lid
31 Large diameter part 32 Small diameter part 33 Connection part
4 Large diameter cylindrical member
41 Locking part 42 Pressure test port 43 Leak test port
5 Small diameter cylindrical member
6 Half-cracked member 61 Half-cracked cylindrical member 62 Arc member
7 Lead work 8 Reinforcement

Claims (4)

At the end of the superconducting cable arranged in a state where a plurality of cable cores are twisted inside the heat insulation pipe,
A terminal structure of a superconducting cable, wherein a flat portion in which a heat insulating tube is compressed into a flat shape together with a plurality of cable cores is formed. A lid that covers the flat portion and seals the end of the heat insulation pipe is fixed to the end of the heat insulation pipe,
This lid body has a large diameter portion that covers the flat portion of the heat insulating tube, and a small diameter portion that is fitted to the outer surface of the heat insulating tube following the large diameter portion,
The large-diameter portion is closed at the end in the axial direction, and a seal is formed on the entire outer periphery of the small-diameter portion and the entire outer periphery near the opening of the small-diameter portion in the heat-insulating tube, so that the lid is airtight on the heat-insulating tube. The terminal structure of the superconducting cable according to claim 1, which is fixed to the cable. The lid is
A large-diameter cylindrical member whose one end that becomes the large-diameter portion is closed, a small-diameter cylindrical member that becomes the small-diameter portion, and the large-diameter cylindrical member and the small-diameter cylindrical member are connected in an airtight manner, and integrated with the end of the small-diameter cylindrical member A ring-shaped connection portion formed,
The terminal structure of a superconducting cable according to claim 2, wherein the small-diameter cylindrical member and the connecting portion are configured by joining together half-cracked members obtained by half-splitting the integrated cylindrical member.   The seal portion is formed by lead processing near the small-diameter portion of the lid and near the opening of the small-diameter portion in the heat insulating tube, and a reinforcing portion made of a synthetic resin is formed around the seal portion. Or the terminal structure of the superconducting cable in any one of Claim 3.

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