Variable-section spring type current lead

Abstract

The invention relates to a variable-section spring type current lead which can be applied to superconducting electrical equipment such as a superconducting fan, a superconducting reactor and a superconducting cable and comprises a conductor substrate, a superconducting conductor and a flange cover plate, the flange cover plate is fixedly connected with a shell of a Dewar container, the conductor substrate penetrates through the flange cover plate, the superconducting conductor is located in the conductor substrate, and the superconducting conductor is located in the conductor substrate. One end of the conductor substrate is connected with the current leading-out terminal; the part, located below the flange cover plate, of the conductor substrate is made of a flexible conductive material, the conductor substrate is of a sandalwood-shaped structure, is in a spiral rising conical spring shape when unfolded and is in a disc shape when flattened, and the cone top of the conical spring shape is located on the bottom face of the flange cover plate. The joint of the conductor substrate and the current leading-out terminal is located at the cone bottom edge of the conical spring shape. Compared with the prior art, the invention has the advantages that: under different working conditions, the change of conduction heat leakage and electric loss can be realized by adjusting the length and the cross section, so that the heat loss is minimized under different working conditions.

Description

Technical Field

[0001] The invention relates to the field of superconducting power accessories, in particular to a variable-section spring-type current lead. Background Art

[0002] As an important transitional accessory in power transmission, the cable lead plays the role of transferring the load from the power supply side to the load side. Especially in the field of superconductivity, the current lead is a load transfer component, which is mainly used to connect the busbar in a normal temperature environment with the superconducting component in a low temperature environment. Based on the characteristics of superconducting power applications, the current lead is usually subjected to a large temperature difference of nearly 200K from normal temperature to low temperature during power transmission. Therefore, due to the temperature difference between the two ends of the current lead, there will be conduction heat leakage on the current lead. At the same time, in the process of transmitting current, the conventional current lead is usually made of copper or aluminum, so due to the existence of resistance, the current lead will heat up when it is powered on. Conductive heat leakage and electrical loss together constitute the heat loss of the current lead. This heat loss will have a serious impact on the current performance of power components, especially superconducting power applications. Due to the superconducting materials, superconducting components generally operate at liquid nitrogen or liquid helium temperatures. When the heat loss of the current lead is too large, and its heat loss value is greater than the cooling power provided by the refrigerator, it will cause the local temperature of the superconducting component to rise too quickly, or the superconducting component cannot be reduced to the required operating temperature, resulting in failure of the superconducting component. However, it is known from the laws of physics that for a current lead of a certain structure, the sum of its conduction leakage heat and electrical loss has a minimum value. And the minimum heat leakage value of current leads of different structures is different. Therefore, for different superconducting power application scenarios, how to balance the electrical loss and conduction loss of the current lead in the application scenario to minimize the total heat loss is a difficult problem in this field.

[0003] The conduction heat leakage and electrical loss of the current lead are related to the cross-section and length of the current lead. At present, solid copper rods or aluminum rods are traditionally used as current leads. The solid copper rod or aluminum rod current lead is connected to the power supply on the room temperature side and the superconducting component on the low temperature side by bolts and nuts. When the length is determined, the cross-section size of the solid copper rod or aluminum rod can be selected according to the size of the operating current. However, this method of selecting the current lead only considers the electrical loss, and does not take into account the influence of conduction heat leakage. Therefore, the cross-section is usually too large. A large cross-sectional area will lead to excessive conduction heat leakage, causing the actual sum of conduction heat leakage and electrical loss to increase, and cannot meet the requirement of minimum total heat loss.

[0004] Therefore, in order to minimize the heat loss of the current lead, theoretical analysis is generally used to calculate the optimal aspect ratio of the solid current lead that can achieve the minimum heat leakage under normal working conditions, that is, the ratio of the current lead length to the cross-sectional area that minimizes the heat leakage under the working condition. The general design method is as follows.

[0005] According to heat transfer theory, we have:

[0006]

[0007] Where k(T) is the thermal conductivity, in W / (m*K); A is the area, in m 2 ; T is temperature, unit is K; is the temperature gradient; ρ(T) is the resistivity, in Ω*m; I a is the current load, in A. For isotropic materials,

[0008]

[0009] According to the Wiedemann-Franz law, the ratio of thermal conductivity k to electrical conductivity σ satisfies:

[0010]

[0011] Where L0 is the Lorentz constant. When the temperature is not too low, L0 = 2.443 × 10 -8 W·Ω·K -2 When the temperature is low (lower than the Debye temperature), the value of L will become smaller. According to the above calculation model, since the thermal conductivity k and the resistivity ρ are both constants, we have:

[0012]

[0013] make Then the general solution of the above formula can be obtained as:

[0014]

[0015] Among them, A and B are unknown constants. According to the boundary conditions of the calculation model, we have:

[0016] x=0,T=T L x=L,T=T H

[0017] Substituting the above formula, we can get:

[0018] A=(T H -T L ) / L+βL / 2, B=T L

[0019] Substituting the above formula, we can get:

[0020]

[0021] Substituting β into the equation, we have:

[0022]

[0023] Differentiating the above equation, we can get the temperature gradient The expression is:

[0024]

[0025] The expression of the heat flux Q of the current lead cross section can be obtained as:

[0026]

[0027] The total heat flux at the base of the current lead is:

[0028]

[0029] Let the shape factor but:

[0030]

[0031] The negative sign indicates that the direction of the heat flux is the negative direction of the x-axis. To find the α that minimizes Q, we can simply take the first-order derivative of α from the above equation, which is:

[0032]

[0033] It should be noted that the above calculation results are for the case where the resistivity ρ (or conductivity σ) and thermal conductivity k are constants. Therefore, there are two problems with this design method:

[0034] 1. The calculated material parameters are constants, but in actual applications, the performance parameters of the materials used to make the current lead change with temperature, which will cause a certain deviation between the design and the actual situation;

[0035] 2. The above design method can only be applied to one constant working condition. In fact, during the application of the current lead, the current it transmits can be large or small, and it will not necessarily be constant in one working condition.

[0036] Therefore, the above two problems lead to a certain deviation in heat loss between the designed current lead and the actual current lead in application. The designed current lead may not necessarily achieve the minimum heat loss in actual application. Summary of the invention

[0037] The purpose of the present invention is to provide a variable-section spring-type current lead in order to solve the problem that the conventional fixed-length current lead cannot achieve minimum heat loss.

[0038] The purpose of the present invention can be achieved by the following technical solutions:

[0039] The present invention provides a variable-section spring-type current lead, which is used to connect a superconducting component and a power transmission end. The superconducting component is encapsulated by a dewar container and connected to the current lead through a current output terminal. The superconducting component comprises a conductor substrate, a superconducting conductor and a flange cover plate. The flange cover plate is fixedly connected to the shell of the dewar container. The conductor substrate passes through the flange cover plate. The superconducting conductor is located in the conductor substrate. One end of the conductor substrate is connected to the current output terminal, and the other end is connected to the power transmission end.

[0040] The material of the conductor substrate located below the flange cover is a flexible conductive material. The conductor substrate is shaped like a sandalwood structure. The sandalwood structure is a spirally ascending conical spring shape when unfolded and a disc shape when flattened. The top of the conical spring shape is located on the bottom surface of the flange cover, and the connection between the conductor substrate and the current lead-out terminal is located at the edge of the bottom of the conical spring shape.

[0041] Furthermore, the cross section of the portion of the conductor substrate located below the flange cover is a parallelogram or a trapezoid.

[0042] Furthermore, a limiting structure is provided on the plane where the current lead-out terminal of the superconducting component is located. The limiting structure is a limiting inclined surface that matches the inclined side of the cross section of the conductor substrate below the flange cover.

[0043] Furthermore, a groove running through the conductor substrate from beginning to end is provided at a portion below the flange cover, the opening of the groove faces the axis of the conical spring shape, and the superconducting conductor is located in the groove.

[0044] Furthermore, the conductor substrate and the superconducting conductor are connected by soldering.

[0045] Furthermore, the conductor substrate and the superconducting conductor are crimped in the groove of the conductor substrate by means of solder 1, and the groove is filled and leveled by means of solder 2.

[0046] Furthermore, the first solder is a conductive solder having a melting point lower than the highest temperature that the superconducting conductor can withstand, and the second solder is a conductive solder having a melting point lower than the melting point of the first solder.

[0047] Furthermore, a protective layer is provided outside the whole body formed by connecting the conductor substrate and the superconducting conductor.

[0048] Furthermore, the portion of the conductor substrate located above the flange cover is a copper bar, the number of the copper bars is one or more, and the conductor substrate is connected to the power transmission end via the copper bar.

[0049] Furthermore, a conductor plate is provided between the conical spring and the copper busbar, and the conductor substrate is connected to the flange cover plate via the conductor plate.

[0050] Compared with the prior art, the present invention has the following advantages:

[0051] 1. The conductor substrate of the present invention is made of a flexible conductive material located below the flange cover. The conductor substrate is in the shape of a spirally ascending "sandalwood-like" conical spring when unfolded, and in the shape of a disc when flattened. When no power is supplied or a small current load is applied, the main body of the current lead mainly maintains a "sandalwood-like" structure. At this time, due to its long length and small cross-section, the main body of the current lead can effectively reduce the conduction heat leakage caused by a large temperature difference as a thermal bridge when the power loss is very small, thereby minimizing the heat leakage of the current lead as much as possible. When a large current needs to be supplied, the main body of the current lead is compressed into a disc shape, at which the flow area is maximized, and a large current can be transmitted with low loss.

[0052] 2. The side of the cross section of the conductor substrate of the present invention located below the flange cover is an inclined side, and there is a limiting structure on the superconducting device side. The limiting structure cooperates with the inclined side to limit the radial displacement of the outermost circle of the current lead body, ensuring that when the flange is moved into place, the current lead body between the flange and the superconducting device is in a compressed state and the contact resistance is minimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the structure of the present invention;

[0054] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0055] Figure 3 It is a half-section view of the present invention;

[0056] Figure 4 A top view of the present invention;

[0057] Figure 5 It is a schematic diagram of the combination of conductor substrate and superconducting conductor;

[0058] Figure 6 It is a schematic diagram of the cross section of a conical spring-shaped structure;

[0059] Figure 7 It is a schematic diagram of the application of the present invention;

[0060] Figure 8 A cross-sectional view of the application of the present invention;

[0061] Fig. 9 for Figure 8 A partial enlarged view of point B in the middle;

[0062] Fig.10This is a schematic diagram of the application of the present invention when no electricity is supplied or a small current is supplied;

[0063] Fig.11 This is a schematic diagram of the application of the present invention when a large current is passed.

[0064] In the figure, 1. conductor substrate, 2. superconducting conductor, 3. flange cover, 4. superconducting component, 5. Dewar container, 6. current lead-out terminal, 7. limiting structure. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0066] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0067] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0068] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0069] Example 1

[0070] The present invention relates to a current lead structure that uses a conical spring structure to achieve variable length and current flow cross-section under different working conditions. The structure has a significant improvement effect over the existing solid fixed-length current lead. The variable cross-section spring current lead of the present invention can be applied to superconducting power equipment such as superconducting fans, superconducting reactors, and superconducting cables, and can also be used in applications where conventional large current loads are transferred.

[0071] The current lead designed by the present invention comprises a conductor substrate 1, a superconducting conductor 2 and a flange cover plate 3. Figure 1-Figure 4As shown. Since the present invention is mainly used for superconducting power applications, in superconducting power applications, the superconducting component 4 is generally placed in a double-layer pressure vessel Dewar container 5 with multiple insulation layers and interlayer vacuum, and immersed in a cooling medium. The Dewar container 5 generally has a sealing requirement.

[0072] At the same time, due to the existence of heat leakage, the cooling medium will evaporate to a certain extent, causing the air pressure inside the Dewar container 5 to rise. Therefore, the role of the flange cover 3 is to make the current lead and the Dewar container 5 cooperate with each other, so that the current lead can be installed on the Dewar container 5, and the current lead is led out through the current lead-out terminal 6. This requires the flange cover 3 to have a high mechanical strength. In addition, since the current lead is a load transmission component, it is generally connected to the power supply side. In power applications, the voltage level of the power supply is generally high. Therefore, the current lead connected to the power supply side also carries a high voltage. The shell of the Dewar container 5 is generally grounded, that is, the potential is zero. Therefore, as a connection between the current lead and the shell of the Dewar container 5, the flange cover 3 also needs to bear the insulation between the current lead conductor and the Dewar container 5, ensuring that the high voltage on the current lead will not be transmitted to the Dewar shell, causing damage to the equipment and injury to personnel. This also requires the material of the flange cover 3 to have good insulation properties.

[0073] Finally, since the current lead usually connects two objects with different temperatures, this will cause temperature distribution in the current lead itself. This temperature distribution will cause thermal deformation of the current lead conductor body and the flange cover 3. And since the current lead conductor part is usually metal and the flange cover 3 is usually insulating material, the thermal expansion coefficients of the two parts are usually different. Therefore, during the thermal deformation process, the thermal deformation of the current lead conductor part and the flange cover 3 are different, and the current lead conductor part and the flange cover 3 may delaminate. Therefore, this requires that the material of the flange cover 3 has a thermal expansion coefficient similar to that of the current lead conductor part, and also requires that the material of the flange cover 3 has a good surface bonding with the current lead conductor part, and the bonding force between the two is as strong as possible.

[0074] In summary, the material used to make the flange cover plate 3 needs to have high mechanical strength, good insulation performance, a thermal expansion coefficient close to that of the current lead conductor material, and strong adhesion to the surface of the current lead conductor portion. Currently, epoxy, ceramic, etc. can be used as materials for making the flange cover plate 3, among which epoxy is the most commonly used material.

[0075] The conductor part of the present invention mainly includes two parts: a conductor substrate 1 and a superconducting conductor 2. The conductor substrate 1 is as shown in FIG. Figure 5As shown. The conductor substrate 1 is structurally divided into two parts, the upper part is a conductor plate with an appropriate cross-section designed according to actual operating conditions. The shape of the conductor plate can be designed according to actual needs, such as cylindrical trapezoid, cylindrical, etc. The height, or thickness, of the conductor plate is mainly designed and calculated based on the pressure that the current lead as a whole can withstand when used as a pressure-bearing head.

[0076] In the present invention, there are two copper bars on the upper part of the conductor plate for connecting to the power supply side. The size and thickness of the copper bars are mainly designed and calculated according to the actual application conditions. In addition, according to the actual application requirements, the number of copper bars can be selected to be multiple, and the arrangement and position of the copper bars can also be redesigned. The lower half of the conductor substrate 1 structure is a slender, "sandalwood-like" conical spring-shaped structure. This structure mainly transforms the conductor part below the original flange cover plate 3 into a compressible and deformable, long spring-shaped structural conductor without changing the conductive cross-section. As a supporting substrate for the superconducting conductor 2, the conductor substrate 1 can serve as a part of the current channel when transmitting large currents, in addition to providing mechanical support for the superconducting conductor 2, and undertakes part of the current transmission. In situations where large currents are not transmitted, it acts as a thermal bridge to reduce heat leakage of the current lead.

[0077] In particular, the cross-sectional shape of the "sandalwood-like" conical spring structure of the conductor substrate 1 is a parallelogram, and a groove is dug on the surface facing the center of the circle, and the groove is used to place the superconducting conductor 2, such as Figure 6 As shown. The width and height of the parallelogram are designed according to the actual application. The height depends on the length of the current lead required when the current lead spring structure is in a compressed and energized state; the width depends on the thermal bridge length required when the current lead is not energized or not running at full load. The reason why the cross section of the spring structure of the flange cover 3 adopts a parallelogram is that when the spring structure is compressed, the spring structure is in a tight state, and each layer of the spring is pressed and in close contact with each other, so as to reduce the contact resistance between layers as much as possible. The parallelogram is a preferred embodiment. In the present invention, the cross-sectional shape is not limited to a parallelogram, and other cross-sectional shapes that can achieve self-limiting can be adopted, such as a cross-sectional shape with inclined side sides of the cross section such as a trapezoid. The depth of the groove on the conductor substrate 1 is selected according to the load current in the actual operation process. The number of superconducting tapes is selected, and then the depth of the groove is determined according to the number of superconducting tapes. At the end of the conductor substrate 1, there is a through hole for connecting to the current access port of the superconducting component 4.

[0078] As mentioned above, the superconducting conductor 2 is a component used for transmitting large current loads, especially in situations where large current is required, and it will take on the role of transmitting most of the current. The superconducting conductor 2 is welded together with the conductor substrate 1 by soldering. If there are multiple superconducting tapes used, it is necessary to weld multiple superconducting tapes together to increase the overall current carrying capacity. The welding between the superconducting conductors 2 and the welding between the superconducting conductor 2 and the conductor substrate 1 adopts the method of crimping + pouring. That is, first use solder one to crimp multiple superconducting conductors 2 and superconducting conductors 2 and conductor substrate 1 together by pressing, and then use solder two to pour on the groove of the conductor substrate 1, and fill the groove with solder two and completely immerse the superconducting conductor 2. Among them, solder one should be selected from solders with good conductivity and a melting point temperature lower than the maximum temperature that the superconducting tape can withstand, and solder two should be selected from solders with good conductivity and a melting point temperature lower than solder one. Superconducting conductor 2 can select superconducting tapes with different packages and different properties according to actual application conditions. After placing the superconducting tape in the groove of the conductor substrate 1 and welding it, the entire surface is plated with a metal such as silver or gold that has good conductivity and is not easily oxidized as a protective layer to prevent oxidation of the conductor substrate 1, while increasing conductivity and reducing surface contact resistance.

[0079] In actual use, the device of the present invention is installed on the required equipment, and the flange cover plate 3 is matched with the flange on the equipment by screws. The current lead body formed by welding the superconducting conductor 2 and the conductor substrate 1 together has its "sandalwood-shaped" conical spring structure, and the end is connected to the current inlet on the superconducting component 4 placed inside the Dewar container 5 by screws, and the copper bar on the conductor substrate 1 is connected to the power supply end by bolts. As mentioned above, there are two conditions when it is used: powered on and not powered on. When not powered on or with a small current load, the current lead body mainly maintains a "sandalwood-shaped" conical spring structure. The current lead body in the "sandalwood-shaped" conical spring structure has a long length and a small cross-section. When the power loss is very small, it can effectively reduce the conduction heat leakage caused by the large temperature difference as a thermal bridge, which can minimize the heat leakage of the current lead as much as possible.

[0080] When a large current needs to be passed, the control flange is moved toward the superconducting device side. During the movement of the flange, the current lead body between the flange and the superconducting device will be compressed. Since the cross section of the current lead conductor is a parallelogram, it can play the role of self-limiting of the "sandalwood-shaped" conical spring structure during the compression process. On the superconducting device side, there is a limiting structure 7 as a limiting ring. The limiting structure 7 is a limiting inclined surface that matches the inclined side of the cross section of the conductor substrate 1 located below the flange cover plate 3, which is used to limit the radial displacement of the outermost circle of the current lead body, ensuring that when the flange cover plate 3 moves into place, the current lead body between the flange cover plate 3 and the superconducting device is in a compressed state and the contact resistance is minimum. When the flange cover plate 3 moves into place and the current lead body is compressed, the copper plate on the flange cover plate 3, the cable lead body, and the copper contacts on the superconducting device are pressed against each other to form a "sandwich" structure. At this time, the flow area is the largest, and a large current can be transmitted with low loss. And the superconducting conductor 2 welded on the conductor substrate 1 can transmit current with low loss, so that the loss is further reduced. After the power is turned off, the control flange moves away from the superconducting device, so that it returns to the "sandalwood-like" thermal bridge state.

[0081] Example 2

[0082] On the basis of Example 1, the present invention is applied to a superconducting fan for extracting a large current when the fan generates electricity, such as Figure 7 and Figure 8 As mentioned above, the conductor substrate 1 of the present invention is connected to the current lead-out terminal 6 on the superconducting component 4 of the superconducting fan by bolts. At the same time, a limiting structure 7 is provided at the end where the current lead-out terminal 6 of the superconducting component 4 of the superconducting fan and the conductor substrate 1 are located. When the "sandalwood-shaped" conical spring structure of the conductor substrate 1 of the present invention is compressed, the limiting structure 7 can be used to limit the position of the outermost elastic coil of the conical spring structure to ensure that when the "sandalwood-shaped" conical spring structure is compressed, each layer of the elastic coils can be pressed tightly and in close contact, thereby reducing the contact resistance between the elastic coils as much as possible, as shown in FIG. Fig. 9 As shown. During installation, as mentioned above, after the upper conductor substrate 1 of the present invention is connected to the current lead-out terminal 6 on the superconducting component 4 of the superconducting fan by bolts, the flange cover plate 3 of the present invention is installed on the flange interface of the container by bolts to ensure airtightness. The flange interface of the superconducting fan container is connected to the superconducting fan body shell by an expansion joint at one end. The copper busbar on the upper part of the conductor substrate 1 of the present invention is connected to the external cable.

[0083] When the superconducting fan is not rotating or rotating at a slow speed, and no current is generated or the generated current is small, the present invention can transmit current without compression, such as Fig.10 As shown. At this time, the electrical loss is small, and the current is transmitted through the conductor substrate 1 and the superconducting conductor 2. The "sandalwood-like" conical spring structure acts as a thermal bridge, which can effectively reduce the conduction heat leakage of the current lead.

[0084] When the output current of the superconducting fan is large or the output is at full power, the flange on the superconducting fan container can be controlled by a certain device to move toward the superconducting fan body, and at the same time, the cabinet of the present invention can be moved toward the superconducting fan body. At this time, the "sandalwood-shaped" conical spring structure under the conductor substrate 1 of the present invention will be compressed. When compressed into place, as described above and as Fig.11 As shown, the "sandalwood-shaped" conical spring structure will be compressed into a solid current lead in the shape of a cylindrical trapezoid. Through the limit structure 7 on the current lead-out terminal 6 of the superconducting component 4 of the superconducting fan, each layer of the spring coil is pressed and closely contacted, and the contact resistance is greatly reduced. At the same time, the upper and lower surfaces of the "sandalwood-shaped" conical spring structure are in close contact with the upper conductor plate structure of the conductor substrate 1 and the current lead-out terminal 6 of the superconducting component 4, respectively, to form a current lead with a larger cross-section, which greatly increases the flow cross-section. The conductor substrate 1 and the superconducting conductor 2 simultaneously bear the transmission of large currents, greatly reducing electrical losses.

[0085] When the high current is delivered or does not need to be delivered, the flange on the superconducting fan container is controlled to return to its original position, and the "sandalwood-shaped" conical spring structure of the present invention is restored from the solid current lead in the shape of a cylindrical trapezoid to the original "sandalwood-shaped" conical spring structure.

[0086] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A variable cross-section spring-type current lead, used to connect a superconducting component (4) and a power transmission end, wherein the superconducting component is encapsulated by a Dewar container (5) and connected to the current lead via a current output terminal (6), characterized in that: It comprises a conductor substrate (1), a superconducting conductor (2) and a flange cover (3), wherein the flange cover (3) is fixedly connected to the outer shell of a Dewar container (5), the conductor substrate (1) passes through the flange cover (3), the superconducting conductor (2) is located in the conductor substrate (1), and one end of the conductor substrate (1) is connected to a current lead-out terminal (6) and the other end is connected to a power transmission end; The material of the conductor substrate (1) located below the flange cover (3) is a flexible conductive material. The conductor substrate (1) is in the shape of a sandalwood-like structure. When unfolded, the sandalwood-like structure is in the shape of a spirally ascending conical spring and in the shape of a disc when flattened. The top of the conical spring is located on the bottom surface of the flange cover (3), and the connection between the conductor substrate (1) and the current lead-out terminal (6) is located at the edge of the bottom of the conical spring.

2. A variable cross-section spring-type current lead according to claim 1, characterized in that: The cross section of the conductor substrate (1) located below the flange cover plate (3) is a parallelogram or a trapezoid.

3. A variable cross-section spring-type current lead according to claim 1, characterized in that: A limiting structure (7) is provided on the plane where the current lead-out terminal (6) of the superconducting component (4) is located. The limiting structure (7) is a limiting inclined surface that matches the inclined side edge of the cross section of the conductor substrate (1) located below the flange cover plate (3).

4. A variable cross-section spring-type current lead according to claim 1, characterized in that: The conductor substrate (1) is provided with a groove running through the flange cover (3) at the bottom thereof, the opening of the groove facing the axis of the conical spring, and the superconducting conductor (2) is located in the groove.

5. A variable cross-section spring-type current lead according to claim 4, characterized in that: The conductor substrate (1) and the superconducting conductor (2) are connected by soldering.

6. A variable cross-section spring-type current lead according to claim 5, characterized in that: The conductor substrate (1) and the superconducting conductor (2) are crimped into a groove of the conductor substrate (1) by means of solder 1, and the groove is filled and leveled by means of solder 2.

7. A variable cross-section spring-type current lead according to claim 6, characterized in that: The first solder is a conductive solder having a melting point lower than the highest temperature that the superconducting conductor (2) can withstand, and the second solder is a conductive solder having a melting point lower than the melting point of the first solder.

8. A variable cross-section spring-type current lead according to claim 5, characterized in that: The conductor substrate (1) and the superconducting conductor (2) are connected to form a whole body, and a protective layer is provided on the outside.

9. A variable cross-section spring-type current lead according to claim 1, characterized in that: The portion of the conductor substrate (1) located above the flange cover plate (3) is a copper bar, the number of the copper bars is one or more, and the conductor substrate (1) is connected to the power transmission end via the copper bar.

10. A variable cross-section spring-type current lead according to claim 9, characterized in that: A conductor plate is disposed between the conical spring and the copper busbar, and the conductor substrate (1) is connected to the flange cover plate (3) via the conductor plate.

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