JP2008211878A - Design method for superconducting cable line and superconducting cable line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting cable line and a design method therefor wherein damage in joints can be reduced and favorable installation workability is achieved. <P>SOLUTION: When coolant is guided into a line L, the amount of movement of each conductor joint of intermediate coupling structure J is determined based on stress generated in the joint by thermal shrinkage in a superconducting cable. It is thereby determined whether or not each joint should be fixed on a case. The amount of movement of each joint is computed on the assumption that all the conductor joints of intermediate coupling structure J contained in the line L are movable relative to the case. Using the results of comparison of the multiple obtained amounts of movement with a threshold value, it is determined whether each conductor joint should be fixed or movable. The number of fixed joints can be reduced by this determination. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a design method for a superconducting cable line having a plurality of conductor connection portions for connecting superconducting conductors of a superconducting cable, and a superconducting cable line. In particular, the present invention relates to a design method for a superconducting cable line that can suppress damage to a line constituent member when a connection location or the like moves due to thermal contraction of the superconducting cable during cooling, and is excellent in laying workability.

  In recent years, a superconducting cable including a cable core including a former, a superconducting conductor, and an electric insulating layer in a heat insulating tube is being put into practical use. A superconducting cable is used for power supply by cooling a cable core with a refrigerant filled in a heat insulating tube and placing the superconducting conductor in a superconducting state.

  When constructing a power supply line over a long distance using a superconducting cable, it is necessary to provide an intermediate connection structure for connecting adjacent cables in the middle of the line. The intermediate connection structure includes a cable connection portion that connects the cable cores and a case that stores the connection portion (see Patent Documents 1 and 2). FIG. 6 is a schematic configuration diagram of the cable connecting portion. The cable connecting portion 140 includes a conductor connecting portion 120 that connects the superconducting conductors 102A and 102B provided to the pair of cable cores 101A and 101B to be connected, and a reinforcing insulating portion 130 that is provided on the outer periphery of the conductor connecting portion 120. (See Patent Document 1). The conductor connecting portion 120 typically includes an end portion of the superconducting conductor 102 and a connecting member 110 that connects the end portions of the superconducting conductor 102 to each other. The reinforcing insulating part 130 is typically formed by winding an insulating material such as synthetic paper or kraft paper around the outer periphery of the conductor connecting part 120.

  The cable core, particularly metal-containing members such as formers and superconducting conductors, when cooled by a refrigerant such as liquid nitrogen, thermally contracts by a maximum of about 0.3%. Due to this heat shrinkage, the conductor connecting portion connected to the superconducting conductor tends to move. The intermediate connection structure described in Patent Document 1 has a configuration in which the conductor connection portion is fixed to the case so that the position of the conductor connection portion with respect to the case does not shift due to this movement. On the other hand, the intermediate connection structure described in Patent Document 2 has a configuration in which the cable core is supported by a holder that can slide in the case, and the cable connection portion is not fixed to the case. With this configuration, the conductor connecting portion can move in the case with heat shrinkage during cooling of the superconducting cable.

JP 2005-210834 A JP 2005-32698 A

  For long-distance superconducting cable lines, it is necessary to construct a plurality of intermediate connection structures. However, conventionally, a design technique for constructing a track having a plurality of intermediate connection structures has not been sufficiently studied. Although Patent Documents 1 and 2 disclose a specific configuration of the intermediate connection structure, when constructing a track having a plurality of intermediate connection structures, the configuration of each intermediate connection structure is described. Not considering.

  For example, all the intermediate connection structures provided in the track may be configured as described in Patent Document 1, that is, a configuration in which the conductor connection portion is fixed to the case (hereinafter, this configuration is referred to as a fixed structure). It is done. Alternatively, all the intermediate connection structures may be configured as described in Patent Document 2, that is, a configuration in which the conductor connection portion is not fixed to the case (hereinafter, this configuration is referred to as a movable structure).

  The movable structure has a relatively simple structure as compared with the fixed structure, and is assembled in a relatively short time. However, if all the intermediate connection structures provided on the track are movable structures, there is a possibility that a conductor connection part that moves more than necessary may be generated due to thermal contraction during cooling of the superconducting cable. If the conductor connecting portion moves greatly, there is a possibility that the reinforcing insulating portion provided on the outer periphery thereof will be damaged. In particular, there is a possibility of causing great damage that causes deterioration of electrical performance.

  Like the cable connection part 140 shown in FIG. 6, the reinforced insulation part 130 formed by winding an insulating material such as synthetic paper or insulating paper around the outer periphery of the conductor connection part 120 is a conductor due to thermal contraction during cooling of the superconducting cable. It is difficult to follow the movement of the connecting part 120. Therefore, when the conductor connecting part 120 moves, in particular, the vicinity of the boundary between the superconducting conductor 102 and the reinforcing insulating part 130 (the part indicated by a small circle in the broken line in FIG. 6) and the cable core 101 (electrical insulating layer) and the reinforcing There is a risk that the reinforcing insulating portion 130 may be displaced and damaged near the boundary with the insulating portion 130 (a portion indicated by a broken large circle in FIG. 6) to deteriorate the electrical insulating performance.

  In particular, when the cooling rate is increased in order to shorten the time for cooling the entire track, the temperature gradient between the refrigerant introduction side and the non-introduction side becomes large, so that a conductor connection portion that moves greatly is likely to occur. The possibility of damage is increased. To reduce the amount of movement of the conductor connection part to prevent such damage, or to reduce the cooling rate so as not to substantially move the conductor connection part, it takes a very long time to cool the entire line, Realistically difficult.

  Even if the reinforcing insulation portion or the like follows the movement of the conductor connection portion and does not shift, if the movement amount of the conductor connection portion is large, the cable connection portion may hit the case and be damaged. If the case is enlarged, the cable connection portion can be prevented from hitting the case, but the case may be installed in a place with a limited size such as a manhole. In such a case, a large case is not preferable.

  Here, in a multi-core superconducting cable having a plurality of cable cores in a heat insulating tube, the conductor connection part moves due to thermal contraction during cooling of the cable by bending and twisting the core so as to have a heat contraction allowance. The amount can be reduced. Therefore, even if all the intermediate connection structures of the track are movable structures, there is a possibility that damage to the connection points can be suppressed. However, a single core superconducting cable with one cable core in a heat insulating tube cannot take heat shrinkage by twisting. Therefore, if all the intermediate connection structures of the track are movable structures, an intermediate connection structure with a large amount of movement is generated, and there is a risk that the connection location may be damaged or hit the case.

  On the other hand, since the fixed structure restricts the movement of the conductor connection portion due to the thermal contraction during cooling of the superconducting cable, the above-described problem such as damage to the reinforcing insulating portion does not occur. However, the fixed structure is relatively more complicated than the movable structure, and it takes time to assemble. Therefore, if the number is large, the laying workability is deteriorated.

  From the above, in constructing a track having a plurality of intermediate connection structures, a track design method that takes into account the installation workability of the entire track and the reduction of damage to the track components due to movement caused by thermal contraction during cooling It is desirable to develop.

  Accordingly, one of the objects of the present invention is to provide a line design method that is excellent in laying workability and can reduce damage to line components in a superconducting cable line having a plurality of intermediate connection structures. is there. Another object of the present invention is to provide a superconducting cable line constructed based on the above design method.

  The design method of the superconducting cable line according to the present invention achieves the above-mentioned object by determining the minimum number of the fixing structures based on the stress generated in the conductor connecting portion due to the thermal contraction during cooling of the superconducting cable.

Specifically, the design method of the superconducting cable line of the present invention includes a plurality of superconducting cables having superconducting conductors cooled by a refrigerant, a plurality of conductor connecting portions connecting the superconducting conductors of adjacent cables, and each conductor connection. This is a design method for designing a track including a plurality of cases that house a section, and includes the following steps.
1. A step of calculating the amount of movement of each conductor connecting portion when the superconducting cable is thermally contracted by cooling, assuming that each conductor connecting portion is movable relative to the case.
The calculation of the amount of movement of each conductor connecting portion is performed based on the stress generated in each connecting portion according to the direction in which the refrigerant is introduced into the line.
2. A step of determining whether each conductor connection portion is a fixed connection portion or a movement connection portion by using a comparison result between the obtained plurality of movement amounts and a threshold value.
When the superconducting cable is thermally contracted by cooling, the fixed connecting part is a conductor connecting part that is fixed to the case so that the superconducting cable cannot be moved relative to the case. In this case, the conductor connecting portion is accommodated in the case so as to be movable relative to the case.

  The design method of the present invention calculates the amount of movement of each connecting portion based on the stress generated in each conductor connecting portion when the superconducting cable is cooled and thermally contracted when the refrigerant is introduced into the line. By comparing the movement amount and the threshold value, it is determined whether each connection portion is fixed to the case or not. With this configuration, the design method of the present invention can reduce the number of structures that take a relatively long time to assemble, that is, the structure that fixes the conductor connection portion to the case, in the plurality of intermediate connection structures provided in the track. In addition, the design method of the present invention makes it easy to sort the conductor connection portion that is considered to have a large movement amount into a fixed connection portion by comparing the movement amount with a threshold value, and damage of the reinforcing insulating portion due to the movement of the connection portion. Can be suppressed. Therefore, by using the design method of the present invention, it is possible to provide a superconducting cable line that is excellent in the laying workability of the line, reduces the deterioration of the electric performance due to the damage of the line constituting member, and is excellent in the electric performance. Hereinafter, the present invention will be described in more detail.

  In the design method of the present invention, each connection portion is moved and connected in a state where the installation position and number of cases for housing the superconducting cable and the conductor connection portion are determined in advance, that is, in a state where the schematic shape of the line is determined. Or a fixed connection. Therefore, when using the design method of the present invention, the route (route) for constructing the track is determined in advance according to the geographical situation (laying layout) of the site for constructing the track. Then, in accordance with the route, the length and number of superconducting cables used for the line, the number of cases, and the installation positions thereof are determined to form a schematic shape of the line.

  The determination of whether each conductor connection provided in the line is either a moving connection or a fixed connection is determined by the movement of each connection when the superconducting cable is thermally contracted mainly during cooling. The amount, in particular, the amount of movement in the longitudinal direction of the cable is obtained, and this amount of movement is used. The amount of movement varies depending on the direction in which the refrigerant is introduced into the track. For example, when cooling is performed by introducing a refrigerant from one end side of the superconducting cable line, a temperature gradient occurs between one end side (introduction side) and the other end side, and the introduction side cooled first by the refrigerant is the other end Shrinks before the side. At this time, the conductor connection portion moves so as to be pulled toward the introduction side that contracts first. And the conductor connection part located in a location with a large temperature difference becomes large. In this way, the behavior of the conductor connecting portion varies depending on the direction of introduction of the refrigerant, and the amount of movement also changes. Therefore, the design method of the present invention determines the amount of movement in consideration of the direction in which the refrigerant is introduced into the track.

  The amount of movement also varies depending on the laying layout. For example, the route profile of the track may have various states such as a bent part and a height difference. Generally, the vicinity of the bent portion of the power cable is largely moved due to heat shrinkage or the like, and when there is a difference in height between the power cables, the high-side portion tends to slide down toward the low-side due to gravity. Since the amount of movement also varies depending on the route profile in this way, it is preferable to obtain the amount of movement in consideration of the laying layout based on the route profile in addition to the refrigerant introduction direction. Specifically, the amount of movement is determined in consideration of physical property values that depend on the laying layout, for example, the curvature of the bent portion of the cable, gravity, and the like. Furthermore, it is preferable to calculate the amount of movement in consideration of design conditions such as the specifications of the superconducting cable, particularly the friction between the cable core and the heat insulating tube, and the specifications of the intermediate connection structure such as the case and the conductor connection portion.

Detailed procedures of the design method of the present invention will be described later, and an outline will be described below.
First, the amount of movement of each conductor connection portion is calculated.
Assuming that all conductor connection portions provided on the track are fixed connection portions, movement of each connection portion due to thermal contraction during cooling of the superconducting cable is restricted. Therefore, the stress accompanying the said heat contraction arises in each conductor connection part, respectively. This stress varies depending on the magnitude of temperature change during cooling, and is obtained by calculation. Then, assuming that all the conductor connection portions are moving connection portions, the amount of movement when the stress applied to each conductor connection portion is released is also obtained by calculation.

Next, using the obtained movement amount, it is determined whether it is a fixed connection part or a mobile connection part.
If the obtained amount of movement is within the allowable range, this conductor connection part is less likely to deteriorate in performance even when housed in the case so that it can be moved relative to the case. It is desirable to fix it to the case so that it cannot move relatively. Therefore, the design method of the present invention compares the obtained movement amount with a threshold value, and uses this comparison result to determine whether it is a fixed connection portion or a movement connection portion. For example, when it is less than the threshold value, the conductor connection portion is determined as a moving connection portion, and when it is equal to or greater than the threshold value, it is determined as a fixed connection portion. The threshold is set in advance in consideration of the case size and the like.

  Specifically, the conductor connection part having the largest movement amount is determined as one of the movement connection part and the fixed connection part. When the conductor connection portion having the maximum movement amount is determined to be the movement connection portion, it is considered that there is no problem such as damage even if all other conductor connection portions are also movement connection portions. Therefore, in this case, all the conductor connection portions included in the track are determined as the moving connection portions. On the other hand, if it is determined that the conductor connection portion having the maximum movement amount is a fixed connection portion, then, assuming a line in a state where this fixed connection portion exists, the movement amount of each conductor connection portion excluding this fixed connection portion Similarly, it is determined whether the conductor connection portion having the largest movement amount is the moving connection portion or the fixed connection portion. When one fixed connection portion is determined in this way, it is determined whether it is sequentially moved or fixed. The selection of the fixed connection portion is repeated until the conductor connection portion having the maximum movement amount is determined to be the movement connection portion. By making such a determination, the design method of the present invention can efficiently sort out the fixed connection portions and reduce the number of fixed connection portions.

  In addition, it is good also considering each movement amount and a threshold value as a fixed connection part by comparing each movement amount and a movement amount more than a threshold value. In this case, although the number of fixed connection portions increases, damage to the connection portion can be reliably prevented.

  Although the installation position is automatically determined by the determination of the fixed connection portion, it may be difficult to construct the fixed connection portion depending on the laying layout even when the movement amount is large and the fixing to the case is desired. For example, there may be a case where there is not enough installation space or construction space for the case for fixing the conductor connection portion. In such a case, the conductor connection portion in the vicinity of the fixed connection portion may be a fixed connection portion. Also, in the case of a track with fixed connection parts at both high and low places, even if the amount of movement due to heat shrinkage during cooling is small, if the high-side conductor connection part is used as a fixed connection part, It is easy to prevent the conductor connection part on the side from falling to the low side due to gravity. Thus, not only the movement accompanying the thermal contraction at the time of cooling but also the laying layout can be taken into consideration, so that a favorable laying workability and a reduction in damage to the connected portion can be more reliably achieved.

  Each conductor connecting portion provided in the track constructed by the designing method of the present invention is at least one of a fixed connecting portion and a moving connecting portion. That is, the track according to the present invention includes a plurality of superconducting cables having superconducting conductors cooled by a refrigerant, a plurality of conductor connecting portions that connect the superconducting conductors of adjacent cables, and a plurality of cases that store the conductor connecting portions. The track includes a fixed connection portion and a movable connection portion. In addition, the line formed by the design method of the present invention allows the case where all the conductor connection parts are lines or fixed connection parts which are moving connection parts.

  The superconducting cable typically has a configuration in which a cable core including a superconducting conductor made of a superconducting material such as a Bi-based oxide superconducting material and an electric insulating layer provided on the outer periphery thereof is housed in a heat insulating tube. The cable core may be a single core or a plurality of cores. In a multi-core cable including a plurality of cable cores, the cores are bent by twisting the cores, and the bent cores are accommodated in the heat-insulated pipe. For this reason, at the time of thermal contraction due to cooling, each cable core is restrained from moving in the longitudinal direction of the cable to some extent due to friction with the heat insulating tube, so that it is difficult for damage to the connection portion. In particular, if the cable core is bent and this bending is used as the heat shrinkage absorption allowance, the cable core can be further restricted from moving in the longitudinal direction of the cable during the heat shrinkage due to cooling. On the other hand, since a single-core cable having a single-core cable core cannot be twisted together, for example, it can be considered to be accommodated (in a snake shape) in the heat insulation pipe so as to have a bend in the heat insulation pipe. However, if the conductor diameter increases with an increase in the capacity of the supplied power, it is difficult to have a sufficient absorption margin in the snake-like storage. For this reason, in a single-core superconducting cable line, a fixed connection portion is essential, and the line design method of the present invention is particularly useful for a line including a single-core cable.

  The conductor connecting portion is constructed by stepping off the end portion of the cable core drawn from the end portion of the superconducting cable to expose the superconducting conductor, and connecting the end portions of the superconducting conductors using a connecting member. The reinforcing insulation provided on the outer periphery uses a solid insulation made of an integrally molded resin such as an epoxy unit, or a laminated insulation formed by winding an insulating material such as synthetic paper or kraft paper around the conductor connection. Can be used, or a combination of both can be used. When the integrally formed body is provided integrally with the connection member in advance, the assembly workability of the conductor connection portion is excellent.

  Examples of the case for accommodating the heat insulating tube for storing the cable core and the conductor connecting portion include a double structure having an inner tube or inner case filled with a refrigerant and an outer tube or outer case covering the outer periphery thereof. . Between the inner and outer pipes or the inner and outer cases, a heat insulating material is arranged or a vacuum is formed to provide a heat insulating structure. An example of the refrigerant is liquid nitrogen.

  The moving connection portion is accommodated so that it can move relative to the case when the superconducting cable is thermally contracted by cooling. For example, a holder that is slidable in the case and can move in the longitudinal direction of the superconducting cable, and supports the cable core and the conductor connecting portion. Can move. At this time, the case may be fixed to the ground, or when the case itself does not move substantially, for example, when the case is installed in a horizontal place, it may not be fixed to the ground. You can just place it on the ground. Whether the case itself is fixed to the ground or not can be determined according to the state of the case installation location.

  The fixed connection portion is accommodated so as not to move relative to the case when the superconducting cable is thermally contracted by cooling. For example, the conductor connection portion is fixed to the case so that it cannot be moved. Specifically, it is possible to fix a reinforcing insulating part such as the above-described solid insulating part or laminated insulating part provided on the outer periphery of the conductor connecting part to the case. Since the solid insulating part itself is excellent in strength, it may be directly fixed to the case. For example, the solid insulating part is fixed to the case by fixing the holding member holding the solid insulating part to the case and fixing the solid insulating part to the holding member. Since the laminated insulating portion is weaker than the solid insulating portion, there is a risk of damage if fixed directly to the case. Therefore, a reinforcing support portion made of a material having excellent strength such as stainless steel or FRP is provided on the outer periphery of the laminated insulating portion, and the reinforcing support portion is fixed to the case. A support piece for fixing the reinforcing support portion is provided in the case. The holding member and the support piece are configured to have a strength that can sufficiently withstand the force when the conductor connection portion is about to move. For example, it is made of stainless steel or FRP. Further, the holding member and the support piece may be formed integrally with the case.

  A holding member and a support piece can be set as the structure which does not prevent the distribution | circulation of the refrigerant | coolant in a case. For example, the holding member may be a plate-like material having a circulation hole, or a plurality of support pieces may be arranged in the case so that gaps are formed between the support pieces, and these gaps may be used for refrigerant circulation.

  Or a holding member can be set as the structure which does not distribute | circulate the refrigerant | coolant in a case. Here, in the line having a plurality of cases, the section for supplying the refrigerant (hereinafter referred to as the refrigerant section) is made one, that is, the refrigerant is introduced from one end side of the line, through the superconducting cable and the case, Consider a configuration in which the refrigerant is discharged from the other end side. At this time, even if a coolant having a desired cooling capacity is supplied to a part of the line, particularly in the vicinity of the introduction side, a refrigerant having a high cooling capacity is sufficient in the other part of the line, particularly in the vicinity of the discharge side. There is a risk that it will not be supplied to. In a long line, a refrigerant having a desired cooling capacity is difficult to be circulated due to a decrease in circulation pressure due to friction between the case, the heat insulating pipe and the cable core, an increase in refrigerant temperature due to intrusion heat, and the like. In such a line, it is desirable to divide the refrigerant section into a plurality of lines in one line. Therefore, at least one refrigerant section is provided on such a track, and a plurality of refrigerant sections are provided. For example, a refrigerant | coolant area can be divided by making a holding member into the plate-shaped material which does not have a flow hole, and utilizing this member for the partition part which interrupts | blocks the distribution | circulation of a refrigerant | coolant.

  The laminated insulating part is immersed in the refrigerant, whereas the solid insulating part is not immersed in the refrigerant. For this reason, when the refrigerant section is provided in the case that houses the conductor connection part having the solid insulating part, the refrigerant flow can be completely divided, and the refrigerant pressure in each section can be easily adjusted. Therefore, it is preferable to apply the partition of the refrigerant section to the case that houses the conductor connection portion having the solid insulating portion.

  Since the fixed connection portion is fixed to the case, movement is also restricted in cases other than heat shrinkage during cooling. On the other hand, the moving connection part can always move within the case, but there are cases where it is desired to restrict this movement to some extent. For example, in the case of a laying layout having a height difference, a bend, etc., there is a possibility that the conductor connecting portion may temporarily move. In order to restrict such temporary movement, it is preferable to use a track having a configuration in which the moving connection portion can be temporarily fixed. For example, the line is provided with a cooling device capable of solidifying the refrigerant filled in the case that houses the moving connection portion that may move temporarily. And the movement of a conductor connection part is mentioned by solidifying the refrigerant | coolant in a case. This movement restriction can be easily released by heating and melting the solidified refrigerant. By changing the state of the refrigerant in this way, temporary movement can be easily restricted and released. The selection of the conductor connection portion that is desired to be temporarily fixed can be determined based on the laying layout and design conditions. It is preferable that at least one cooling device is provided on the track.

  The method for designing a superconducting cable line of the present invention can design a line that can suppress damage to connection points due to thermal contraction during cooling of the cable and that has excellent laying workability by reducing the number of fixed connection parts. Moreover, the superconducting cable line of the present invention is excellent in electrical performance and installation workability.

Hereinafter, a procedure for designing a superconducting cable line and constructing the line according to this design will be described in detail.
<Design example 1>
1 is a plan view schematically showing a schematic shape of a superconducting cable line having a plurality of intermediate connection structures, and an upper graph in FIG. 1 is a graph showing a temperature distribution along the line. The graph below 1 is a graph showing the stress distribution along this line. In this example, in order to simplify the description, a straight route having no bending and no height difference is used as the laying layout.

(1) Formation of the approximate shape of the track First, based on the path for constructing the track, the number of superconducting cables of a predetermined length required at the location where the track is to be installed, the number of intermediate connection structures, and their installation positions are examined. Determine the approximate shape of the track. Here, consider a case where a line L extending from point A to point B is constructed with six superconducting cables C and five intermediate connection structures J and installed as shown in FIG. Termination connection structures T _a and T _b are provided at both ends (point A and point B) of the line L. The termination connection structures T _a and T _b are usually fixed to the ground. Each intermediate connection structure J includes a conductor connecting portion (not shown) for connecting superconducting conductors (not shown) provided in a cable core (not shown) drawn from the end of the adjacent superconducting cable C, and this And a case (not shown) for housing the conductor connection portion.

(2) Examination of temperature distribution and stress distribution Next, we examine the temperature distribution and stress distribution of the line when refrigerant is introduced from one end of the line. Here, a case is considered where the entire line L is set as one refrigerant section, and the refrigerant is introduced from the point A. That is, the refrigerant introduction direction is a direction from point A to point B. In addition to the refrigerant introduction direction, refrigerant introduction conditions such as refrigerant temperature, flow rate, flow velocity, specifications of superconducting cable C (physical properties and sizes of superconducting conductors, cable cores, heat insulation pipes, etc.) and specifications of intermediate connection structure J The temperature distribution for each time is determined according to the physical property value and size of the conductor connection part, the size of the case, and the like.

  Here, the amount of shrinkage of the superconducting conductor and the conductor connecting portion varies depending on the temperature. Therefore, as the temperature gradient (temperature difference) during the cooling of the line is larger, the amount of contraction at each point of the line is different, and the amount by which the conductor connecting portion moves from the high temperature side to the low temperature side increases. Therefore, a temperature distribution when the temperature gradient is the largest is selected from the obtained plurality of temperature distributions. As shown in the upper graph of Figure 1, the selected temperature distribution is closer to the refrigerant temperature (around 77K when the refrigerant is liquid nitrogen) as it is closer to point A. The neighborhood is normal temperature.

  Assuming that all cables and all intermediate connection structures J constituting the track have a structure in which the cable core and the conductor connection portion are relatively immovable with respect to the heat insulating tube and the case, the above temperature distribution is selected. The stress distribution of the line based is represented as in the lower graph of FIG. As shown in Fig. 1, the stress is applied to each point on the track by cooling with the refrigerant, and the closer to point A, the larger the stress is.The closer to point B, the smaller the stress is. Because it is not received, it is not loaded. The stress acting on each point on the track is determined according to the refrigerant introduction conditions and the specifications of the superconducting cable C.

(3) Calculation of travel distance For all cables and all intermediate connection structures J that make up the track, the cable core and conductor connection are movable relative to the heat insulation pipe and case, and the friction coefficient is Assume 0. At this time, the stress applied to the line is released, and each conductor connection portion moves. Amount of movement depends on stress, for example, a conductor connecting portion of the intermediate connection arrangement J ₁ is the largest. Although the friction coefficient is not considered here, strictly speaking, the stress is calculated in consideration of the friction coefficient. Note that, in the stress distribution graph in Fig. 1, the hatched area S ₁ and the right side of the hatched region S ₂ on the left side is the same area, region S ₁ is the amount of shrinkage, the area S ₂ corresponds to the elongation amount.

  Here, the stress F applied to the object due to the temperature difference Δt is F = E × A × α × (Δt), where E is the Young's modulus of the object, A is the cross-sectional area, and α is the linear expansion coefficient. It is represented by α × (Δt) is the amount of heat shrinkage, and the amount of movement of the conductor connecting portion is obtained from this amount of heat shrinkage.

  Therefore, using the stress applied to each conductor connection part and the Young's modulus and cross-sectional area of each conductor connection part, the amount of heat shrinkage is obtained in consideration of the friction coefficient. The amount of movement of the connecting portion (the amount of movement of the superconducting cable in the longitudinal direction) is obtained. A more realistic amount of movement can be obtained by considering the friction coefficient.

(4) Determination of moving connection or fixed connection If the amount of movement of the obtained conductor connection can be tolerated, for example, the case has a sufficient size, and the conductor connection is equivalent to this amount of movement. If the case does not hit the case even if it moves inside, it is considered that there is no problem even if the conductor connecting portion is housed in a state in which it can move relative to the case. Therefore, the conductor connecting portion is a moving connecting portion that is accommodated in the case so as to be relatively movable with respect to the case.

  On the other hand, when the amount of movement of the obtained conductor connection part is unacceptable, that is, when the conductor connection part moves in the case by this amount of movement, it may hit the case or damage the connection part. It is necessary to store the connection part so that it cannot move with respect to the case. Therefore, the conductor connection portion is a fixed connection portion that is fixed to the case so as not to move relative to the case.

  The determination as to whether each conductor connection portion is a moving connection portion or a fixed connection portion is performed as follows. First, the movement amount of each intermediate connection structure is compared, and the maximum movement amount is selected. Next, considering a case size and the like, a preset threshold value is compared with the maximum movement amount. For example, when the amount of movement is equal to or greater than a threshold value, the conductor connection portion having the maximum movement amount is a fixed connection portion. When the amount of movement is less than the threshold value, the connection portion is a movement connection portion.

  When the said conductor connection part is determined as a movement connection part, it is thought that another conductor connection part may be a movement connection part. Therefore, in this case, all the conductor connection portions included in the track are determined as the moving connection portions. On the other hand, when the said conductor connection part is determined as a fixed connection part, the line of the state where this fixed connection part exists is assumed, and each conductor connection except this fixed connection part is provided among the conductor connection parts provided in the line. The amount of movement of the part is calculated again. In other words, the amount of movement of each conductor connection portion is calculated again on a line having one fixed connection portion. In the same manner as described above, the maximum movement amount is compared with the threshold value, and it is determined whether the conductor connection portion having the maximum movement amount is a fixed connection portion or a movement connection portion. In this way, the fixed connection portion is sequentially determined, and by this determination, the maximum movement amount is calculated again assuming the line where the fixed connection portion exists, and this procedure is repeated until the maximum movement amount becomes less than the threshold value. The same threshold value may be used continuously, or correction may be added as appropriate.

  In addition, about the conductor connection structure which has the situation that construction space cannot fully be taken and it is difficult to set it as a fixed connection part, it may determine in advance as a movement connection part and may perform the above-mentioned procedure.

  The above procedure can be performed using a computer including storage means, calculation means, comparison means, determination means, and the like. For example, each means of the computer is operated as follows.

  First, refrigerant introduction conditions such as refrigerant temperature, flow rate, flow velocity, physical properties of the superconducting conductor and heat insulating tube (Young's modulus, coefficient of linear expansion, coefficient of friction between the heat insulating tube and cable core, etc.) and size (cross-sectional area, Preliminary input of superconducting cable specifications such as length and volume, intermediate connection structure specifications such as physical properties (such as Young's modulus and linear expansion coefficient) and size of the conductor connection part, and case size . Further, the schematic shape of the line (the length and number of superconducting cables along the laying layout, the number of intermediate connection structures) is also input in advance to the data storage means.

  The temperature calculation means calculates the temperature distribution using the data called from the data storage means, and the stress calculation means uses the obtained temperature distribution and the data called from the data storage means to Calculate the stress applied to the conductor connection. The first movement amount calculation means calculates the movement amount of each conductor connection part due to thermal contraction during cooling, using the obtained stress and the data called from the data storage means. The amount of movement is preferably calculated in consideration of the coefficient of friction between the cable core and the heat insulating tube.

  The first movement amount comparison means compares the obtained movement amounts and selects a maximum movement amount. A threshold value set in consideration of the size of the case is input to the threshold value storage means, the first threshold value comparison means compares the maximum movement amount with the threshold value called from the threshold value storage means, and the first case determination means Determines that the conductor connection portion is a fixed connection portion when the maximum movement amount is equal to or greater than a threshold value, and determines that the conductor connection portion is a movement connection portion when the maximum movement amount is less than the threshold value. If it is determined that the conductor connection portion is a moving connection portion, the first case determination means determines that all conductor connection portions are movement connection portions.

  If it is determined that the connection portion is a fixed connection portion, the second movement amount calculation means calculates the movement amount of each conductor connection portion excluding the fixed connection portion. At this time, the second moving amount calculating means is configured to calculate the moving amount of each conductor connecting portion assuming the line where the fixed connecting portion exists. The second movement amount comparison means selects the maximum movement amount from the newly obtained movement amount, the second threshold value comparison means compares the selected maximum movement amount and the threshold value, and the second case determination means determines the maximum movement amount. It is determined and determined whether the conductor connection portion, which is the amount of movement, is a fixed connection portion or a movement connection portion. Hereinafter, the same is repeated until the case determination unit determines that the mobile connection unit is used (until the maximum movement amount becomes less than the threshold). By using a computer in this way, it is possible to easily design a track.

(5) Construction of the track Based on the above design, the superconducting cable will be laid and the intermediate connection structure will be built to construct the superconducting cable track. The constructed line is, for example, a line in which a fixed connection part and a moving connection part are mixed.

  Based on the design method described above, an appropriate number of fixed connection portions and movable connection portions provided in the superconducting cable line can be easily obtained. Therefore, this design method can suppress the deterioration of electrical performance due to thermal contraction during cooling, and reduce the number of intermediate connection structures having a fixed connection portion having a relatively complicated configuration. As a result, the track laying workability is excellent.

  In particular, this design method can minimize the number of fixed connections by determining the fixed connections one by one. In addition, since the superconducting conductor connected to the fixed connection part is restricted from moving due to thermal contraction during cooling, the conductor connection part located in the vicinity of the fixed connection part, particularly on the upstream side of the fixed connection part when viewed from the refrigerant introduction direction, is The movement of the superconducting conductor due to the heat shrinkage during cooling is reduced by the restriction of movement of the superconducting conductor. Accordingly, since the selected conductor connection portion in the vicinity of the fixed connection portion has a small amount of movement, the possibility of being determined as the movement connection portion is increased. Therefore, this design method can effectively reduce the number of fixed connection portions.

<Use of design example 2 installation layout>
《Bending, height difference》
FIG. 2 (I) is a schematic plan view of a superconducting cable line having a bend, and (II) is a schematic side view of the superconducting cable line having a height difference. In the above design example 1, although a simple laying layout has been studied, in practice, there may be a bend B or a height difference as shown in FIG. In the case of such a layout, the amount of movement of the conductor connection portion increases.

For example, if having a B bend laying layout as shown in FIG. 2 (I), when the superconducting cable is thermally contracted, the cable core toward the bent portion B in the intermediate connection arrangement J ₂ fed out by cooling, that amount core The amount of movement increases. Thus, viewed from the refrigerant introduction direction, bending the conductor connection portions of the intermediate connection arrangement J ₂ located on the upstream side of B, the amount of movement is increased, likely to be determined to the fixed connecting part is increased.

Alternatively, if there is a height difference in laying layout as shown in FIG. 2 (II), the conductor connection section of the intermediate connection arrangement J ₃ present in high altitude side, when the superconducting cable is thermally contracted by cooling, the heat shrinkable While moving to the low side, it tries to move to the low side due to gravity. Therefore, the conductor connecting portion of the intermediate connection arrangement J ₃ is, the amount of movement is increased, the more likely it is determined that the fixed connection.

  Therefore, the number of fixed connection portions can be more appropriately selected by determining the amount of movement of the conductor connection portions in consideration of the laying layout in addition to the refrigerant introduction direction.

  In this design example, when the movement amount is calculated by a computer, the laying layout conditions such as a curvature of curvature and a head are input to the data storage means in advance so that the moving amount can be calculated using the laying layout. deep. And a calculating means is comprised so that a movement amount may be calculated using the called data.

<Others>
Even when it is determined as the fixed connection portion, it may be difficult to construct the fixed connection portion due to, for example, a shortage of the installation space due to the installation layout. Therefore, when it is determined that the fixed connection unit is used, a configuration may be added in which it is determined whether or not the fixed connection unit can be constructed with reference to the laying layout. For example, the configuration is as follows.

  First, according to the procedure described in the design example 1, when it is determined that the connection portion is a fixed connection portion, it is determined whether or not the fixed connection portion can be constructed by referring to the laying layout. If it is difficult to construct a fixed connection part, it is determined as a moving connection part, and whether or not a conductor connection part in the vicinity of this moving connection part, for example, an upstream conductor connection part when viewed from the refrigerant introduction direction can be used as a fixed connection part. This determination is performed until a conductor connection portion that can be constructed and a fixed connection portion can be constructed is selected. Alternatively, it may be determined whether there is a fixed connection in the vicinity of the determined mobile connection. As described above, the fixed connection portion is present in the vicinity of the conductor connection portion that is originally determined to be desirable, so that the movement amount of the conductor connection portion can be reduced.

  In this design example, when the above procedure is performed by a computer, the laying layout conditions such as the state of the construction location of each conductor connection portion are input to the data storage means in advance. Then, when the case determination unit determines that the connection is a fixed connection unit, the first construction determination unit refers to the called data and determines whether or not the fixed connection unit can be built. If it is impossible, it is determined as a mobile connection unit. Then, the second construction determination means determines whether or not the conductor connection portion in the vicinity of the conductor connection portion determined to be the moving connection portion can be a fixed connection portion.

<Design Example 3 Separation of refrigerant section>
In the design example 1, the configuration in which one entire line is used as one refrigerant section has been described. One track may have a plurality of refrigerant sections. The division of the refrigerant section is provided in the case that houses the solid connection portion.

  For example, after determining the solid connection part in accordance with the design example 1, it is determined whether or not a refrigerant section break is provided in the case housing the solid connection part. When there are a plurality of solid connection parts, the presence or absence of a refrigerant section break is determined for each case. Refrigerant supply systems (refrigerant storage tanks, refrigerators, pumps, etc.) are constructed in each divided refrigerant section.

  When this determination is performed by a computer, after the fixed connection portion is determined, the refrigerant section determination means determines whether or not to provide a partition of the refrigerant section in the case that houses the fixed connection section. When the refrigerant section is divided, the refrigerant introduction state (such as the refrigerant introduction direction) changes as the entire line, and the temperature distribution of the entire line also changes with this change. That is, since a new refrigerant section is formed, the amount of movement of the conductor connecting portion is different from that in the case where there is one refrigerant section first. Therefore, when it is determined that the refrigerant section is divided, the n-th movement amount calculation means (n is an arbitrary natural number equal to or greater than 2) calculates the movement amount of each conductor connection portion for a new refrigerant section. That is, the movement amount of the conductor connecting portion is calculated for each of a plurality of sections. At this time, information on the new refrigerant section (refrigerant temperature, flow rate, flow rate, refrigerant introduction direction, section range, etc.) is input to the data storage means.

<Design Example 4 Movement over time>
In the above-described design examples 1 to 3, the movement of the moving connection portion is allowed. However, if there is a bend or height difference in the laying layout, it is considered that the amount of movement of the conductor connection portion increases over time. If the amount of movement is large to some extent, it is desirable to temporarily fix the conductor connection portion. . Therefore, when it is determined that the moving connection portion is determined, it is further determined by referring to the laying layout whether or not there is a movement over time, and the movement amount is calculated. Provide a structure that can be fixed securely. Temporary fixing includes, for example, solidifying the refrigerant in the case. Therefore, when such a moving connection portion exists, a cooling device for solidifying the refrigerant is installed.

  When this determination is performed by a computer, after the movement connecting unit is determined, the temporal movement determination means refers to the laying layout to determine the presence or absence of movement over time. The amount of movement is calculated using data based on the laying layout. The temporal fixed comparison means compares the calculated movement amount with a preset threshold value, and the temporal fixed determination means determines that temporary fixation is necessary when the movement amount is equal to or greater than the threshold value.

  Thus, the design method of the present invention can design a line that can suppress not only the movement of the conductor connection part during cooling before the line operation but also the movement of the conductor connection part during line operation.

<Superconducting cable>
As the superconducting cable used for the track, either a single-core cable or a multi-core cable in which a single-core or multiple-core cable core is housed in a heat insulating tube can be used. The cable core includes a configuration including a former, a superconducting conductor, and an electrical insulating layer in order from the center. A configuration in which an internal semiconductive layer is provided inside the electrical insulating layer and an external semiconductive layer is provided outside is also possible.

  The former is composed of, for example, a copper stranded wire. The superconducting conductor is formed, for example, by winding one or more layers of a tape wire in which a Bi-based oxide superconducting material is encapsulated in a silver sheath on the former. When the superconducting conductor is a multilayer, an interlayer insulating layer made of an insulating material such as kraft paper may be provided between the layers. The electrical insulating layer is formed by, for example, winding semi-synthetic insulating paper such as PPLP (registered trademark) or insulating paper such as kraft paper. Furthermore, it is good also as a cable core which equips the outer periphery of an electrical insulation layer with the external superconducting layer which consists of the said tape wire material, or provides the protective layer which consists of kraft paper etc. in the outer periphery of an external superconducting layer.

  As the heat insulating pipe, for example, a double structure pipe made of an inner pipe made of SUS corrugated pipe and an outer pipe can be used. The inner tube accommodates the cable core and is filled with a coolant that cools the core. Between the two tubes, a heat insulating structure in which a vacuum or a heat insulating material such as a super insulation is arranged is adopted. The refrigerant is typically liquid nitrogen. You may provide the anti-corrosion layer which consists of polyvinyl chloride etc. in the outer periphery of a heat insulation pipe | tube.

<Intermediate connection structure>
FIG. 3 is a schematic configuration diagram of an intermediate connection structure provided in the superconducting cable line. In the drawings, the same reference numerals denote the same items. In FIG. 3, a three-core superconducting cable is shown, but a single core may be used.

  The intermediate connection structure provided on the track connects adjacent superconducting cables 100A and 100B, and is constructed as follows, for example. Pull out the cable cores 101A and 101B from the ends of the pair of superconducting cables 100A and 100B to be connected, step off the ends of the cores 101A and 101B to expose the superconducting conductors 102A and 102B, and a highly conductive material such as copper or aluminum The end portions of the two conductors 102A and 102B are connected through a connecting member 110 made of the above, thereby forming a conductor connecting portion 120. The connecting member 110 is, for example, a solid rod-like material having a hole (not shown) into which a superconducting conductor and a former (not shown) can be inserted at both ends, and the superconducting conductor and the former are respectively inserted into the holes. Insert the superconducting conductor with solder, for example. A reinforcing insulating part 130 is constructed by winding an insulating material such as synthetic paper around the outer periphery of the conductor connecting part 120. As appropriate, the cable connection portion 140 can be constructed by short-circuiting or connecting an external superconducting layer (not shown).

  The cable core 101 introduced into the case 200 and the cable connection part 140 having the conductor connection part 120 and the reinforcing insulation part 130 are held by the holder 150 so as not to be damaged by contact with the case 200 (inner case 201). To do. The holder 150 is configured to hold the three-core cable core 101 in a separated state. As the holder 150 that holds the moving connection portion, a holder that can move in the longitudinal direction of the cable in the case 200 is used.

  An intermediate connection structure can be constructed by assembling the case 200 on the outer periphery of the cable connection portion 140. The case 200 has, for example, a double structure composed of an inner case 201 and an outer case 202 made of SUS, and a case having a heat insulating structure similar to the heat insulating pipe of the superconducting cable described above can be used. In particular, the case 200 has a configuration in which a pair of split pieces that can be separated in the longitudinal direction of the cable are combined and integrated, and a connecting portion and the like can be easily assembled. The case 200 is configured to collectively store the cable connection portions of the three-core superconducting cable, and the number of cases storing the connection portions is minimal.

《Structure with fixed connection and solid insulation》
When the conductor connection portion is a fixed connection portion, the cable connection portion is configured so as to be fixed to the case. For example, in the case of a cable connecting portion having a solid insulating portion having excellent strength, the conductor connecting portion is fixed to the case as follows.

  FIG. 4 is a schematic configuration diagram of a cable connecting portion including a solid insulating portion. Although FIG. 4 shows a single-core superconducting cable, it may be multi-core. This also applies to the example shown in FIG. The cable connecting portion 141 is integrally provided with a solid insulating portion (stress cone epoxy unit) 11 made of an epoxy resin on the outer periphery of the connecting member 111, and the solid insulating portion 11 is provided on a plate-like material (holding member) 13 described later. By fixing the plate member 13 to the case 200 (inner case 201), the conductor connecting portion 121 is fixed to the case 201.

  The connection member 111 has a configuration similar to that of the connection member 110, and includes the solid insulating portion 11 on the outer periphery. The solid insulating portion 11 is a spindle-shaped material that is tapered from the central portion toward both ends, and includes a ring-shaped flange 12 that protrudes outward at the central portion. The plate-like material 13 is made of SUS and has an outer shape along the inner periphery of the inner case 201. The plate-like member 13 has a through hole at the center, and the solid insulating portion 11 is inserted into the through hole. The flange 12 is brought into contact with one surface of the plate-like material 13, the flange 12 is sandwiched between the plate-like material 13 and the ring-shaped holding material 14, and the plate-like material 13 and the holding material 14 are tightened with bolts and nuts. The solid insulating part 11 is fixed to the plate-like material 13. This plate-like material 13 is fixed to the inner case 201 by welding. By this fixing, the conductor connecting portion 121 is fixed to the inner case 201. In addition, on the outer circumferences of the superconducting conductors 102A and 102B, the connecting member 111, and the solid insulating portion 11, a laminated insulating portion 131 in which an insulating material is wound is appropriately formed.

  Since the plate-like material 13 receives a force when the conductor connecting portion tries to move, the plate-like material 13 is configured to be able to sufficiently withstand this force. Further, the plate-like material 13 is provided with a circulation hole 13h for circulating the refrigerant. When the refrigerant section is provided in the case 200, there is no need to provide a flow hole in the plate-like material.

<Structure with fixed connection and laminated insulation>
In the case of a cable connection part that does not have a solid insulation part, the conductor connection part is fixed to the case as follows. FIG. 5 is a schematic configuration diagram of a cable connecting portion including a reinforcing support portion. The cable connection part 142 is the same as the cable connection part 140 shown in FIG. 3 in that the connection member 110 and the insulating material are wound and laminated, and the cable connection part 142 is the same as the cable connection part 140 shown in FIG. The reinforcing support portion 160 is provided on the outer periphery of 130.

  The reinforcing support portion 160 is made of FRP, and includes a cylindrical portion 161 that covers the outer periphery of the reinforcing insulating portion 130, and a flange portion 161f that protrudes outward from the outer peripheral surface of the cylindrical portion 161. The cylindrical portion 161 has a shape along the reinforcing insulating portion 130, which is tapered from the central portion toward both ends, and is configured by combining a pair of divided pieces that can be divided in the longitudinal direction of the cable. is there. The flanges 161f are provided on both edges of each split piece, both split pieces are arranged on the outer periphery of the reinforcing insulating part 130, the flange portions 161f of both split pieces are joined, and tightened with bolts and nuts to form a cylindrical shape The part 161 is fixed to the outer periphery of the reinforcing insulating part 130. A support piece 201a protrudes from the inner peripheral surface of the inner case 201, and the reinforcing support portion 160 is fixed to the inner case 201 by fixing the flange portion 161f with bolts and nuts. With this fixing, the cable connecting portion 142 is fixed to the inner case 201, and the conductor connecting portion 120 is fixed to the inner case 201.

  Since the support piece receives a force when the conductor connecting portion 120 tries to move, the support piece is configured to be able to withstand this force sufficiently. In addition, the support piece may be configured to be integrally provided over the entire inner peripheral surface of the inner case 201, or may be configured to have a plurality of support pieces provided on the inner peripheral surface. In particular, by providing each support piece so as to have a gap between the support pieces, the refrigerant can be circulated using this gap.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration.

  The method for designing a superconducting cable line of the present invention can be suitably used for designing a power supply path for AC power transmission or DC power transmission. Moreover, the superconducting cable line of the present invention can be suitably used for a power supply path for AC power transmission or DC power transmission.

It is explanatory drawing used for description of the design method of a superconducting cable line, the center of a figure is a top view which shows the outline shape of a line typically, the upper graph of a figure is the graph of the temperature distribution along this line, a figure The graph below is a graph of the stress distribution along this line. (I) is a schematic plan view of a superconducting cable line having a bend, and (II) is a schematic side view of a superconducting cable line having a height difference. It is a schematic block diagram which shows an example of the intermediate connection structure provided in a superconducting cable track. It is a partial schematic block diagram of the cable connection part which provides a solid insulation part. It is a partial schematic block diagram of the cable connection part which provides a reinforcement support part. It is a partial schematic block diagram of a cable connection part.

Explanation of symbols

11 Solid insulation 12 Flange 13 Plate 13h Flow hole 14 Holding material
100A, 100B Superconducting cable 101,101A, 101B Cable core
102,102A, 102B Superconducting conductor 110,111 Connection member 120,121 Conductor connection
130 Reinforced insulation 131 Laminated insulation 140, 141, 142 Cable connection
150 Holder 160 Reinforcement support part 161 Cylindrical part 161f Flange part
200 Case 201 Inner case 201a Support piece 202 Outer case

Claims (7)

Designing a track comprising a plurality of superconducting cables having superconducting conductors cooled by a refrigerant, a plurality of conductor connecting portions for connecting the superconducting conductors of adjacent cables, and a plurality of cases for storing the respective conductor connecting portions. A method of designing a superconducting cable line,
Assuming that each conductor connection portion is movable relative to the case, a step of calculating the amount of movement of each conductor connection portion when the superconducting cable is thermally contracted by cooling,
Using the obtained comparison results of the plurality of movement amounts and threshold values, the step of determining whether each conductor connection portion is a fixed connection portion or a movement connection portion,
The amount of movement of each conductor connection portion is calculated based on the stress generated in each connection portion according to the direction of introduction of the refrigerant to the line,
The fixed connection portion is a conductor connection portion that is fixed to the case so as not to move relative to the case when the superconducting cable is thermally contracted by cooling,
The method of designing a superconducting cable line, wherein the moving connecting portion is a conductor connecting portion that is accommodated in the case so as to be relatively movable with respect to the case when the superconducting cable is thermally contracted by cooling.   2. The method of designing a superconducting cable line according to claim 1, wherein the amount of movement of each conductor connecting portion is calculated based on a laying layout of the line. A superconducting cable line comprising a plurality of superconducting cables having superconducting conductors cooled by a refrigerant, a plurality of conductor connecting portions for connecting the superconducting conductors of adjacent cables, and a plurality of cases for storing the respective conductor connecting portions. There,
Each conductor connection portion is at least one of a fixed connection portion and a movable connection portion,
The fixed connection portion is a conductor connection portion that is fixed to the case so as not to move relative to the case when the superconducting cable is thermally contracted by cooling,
The superconducting cable line, wherein the moving connecting portion is a conductor connecting portion that is accommodated in the case so as to be relatively movable with respect to the case when the superconducting cable is thermally contracted by cooling. On the outer periphery of the fixed connection part, a solid insulating part made of an integrally molded body is provided,
4. The superconducting cable line according to claim 3, wherein the solid connection portion is fixed to the case by fixing the solid insulating portion to the case. On the outer periphery of the fixed connection portion, a laminated insulating portion formed by winding an insulating material is provided, and a reinforcing support portion is further provided on the outer periphery of the laminated insulating portion,
4. The superconducting cable line according to claim 3, wherein the fixed connecting portion is fixed to the case by fixing the reinforcing support portion to the case. The track includes a cooling device that solidifies the refrigerant filled in the case that houses the fixed connection portion,
4. The superconducting cable line according to claim 3, wherein the fixed connection portion is fixed to the case by a refrigerant solidified by a cooling device.   5. The superconducting cable line according to claim 3, further comprising a partition part that divides a refrigerant section in the line in a longitudinal direction of the line in a case that accommodates the fixed connection part.

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