Low-voltage bipolar superconducting cable

Abstract

The invention provides a low-voltage bipolar superconducting cable. Comprising a cable framework (1), a positive polarity superconducting tape group (2), a negative polarity superconducting tape group (3) and an insulating material (4), the positive superconducting tape group (2) and the negative superconducting tape group (3) are arranged on the framework (1) at intervals in a central symmetry manner, the insulating material (4) is wound on the positive superconducting tape group (3), tapes used by the positive superconducting tape group (2) and the negative superconducting tape group (3) are of the same specification, and gaps between adjacent tapes are fixed. According to the low-voltage bipolar superconducting cable configuration design provided by the invention, various operation modes can be realized through external electrical topology change, and the application adaptability, flexibility and reliability of the superconducting direct-current cable are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting cables, in particular to a low-voltage bipolar superconducting cable. Background Art

[0002] High-temperature superconducting cables offer numerous advantages, including high capacity, low loss, compact footprint, and environmental friendliness. Compared to conventional cables, their AC impedance is only one-tenth that of conventional cables, significantly reducing transmission line losses and improving energy efficiency. For the same size, high-temperature superconducting cables have a transmission capacity five times that of conventional cables, demonstrating their high-density transmission capabilities. In today's emerging urban development, we must consider the increasing demand for electricity and energy, as well as the limited transmission corridors in certain areas. With its many advantageous properties, high-temperature superconducting transmission offers a viable solution to the challenges facing urban power transmission and distribution.

[0003] In the development of high-temperature superconducting cables, various countries have continuously explored the optimization and improvement of superconducting cable configurations. AC superconducting cables have successively developed three-phase discrete configurations, three-core all-in-one configurations, and three-phase coaxial configurations. Each has its own characteristics and advantageous application scenarios.

[0004] Common superconducting DC cables currently include bipolar coaxial and monopolar configurations. The bipolar coaxial configuration is structurally similar to tripolar coaxial AC superconducting cables and exhibits self-magnetic field cancellation, which confines the magnetic field within the cable, allowing the cable to be placed closer to other sensitive equipment and accommodating a wider range of installation requirements. This self-shielding property also eliminates the need for a superconducting shield, reducing the amount of superconducting tape used and, consequently, application costs.

[0005] Under low-voltage DC transmission (e.g., below 1 kV) application conditions, the flexibility of bipolar coaxial superconducting cables is subject to certain limitations. For example, they only have two operating modes: bipolar operation and unipolar operation after short-circuiting the inner and outer poles. Summary of the Invention

[0006] The present invention provides a low-voltage bipolar superconducting cable to effectively improve the performance of a superconducting DC cable.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0008] A low-voltage bipolar superconducting cable comprises: a cable skeleton (1), a positive polarity superconducting tape group (2), a negative polarity superconducting tape group (3) and an insulating material (4);

[0009] The positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) are both arranged on the skeleton (1) in a centrally symmetrical manner, and the insulating material (4) is wound on the positive polarity superconducting tape group (3). The tapes used in the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) are of the same specification, and the gaps between adjacent tapes are fixed.

[0010] Preferably, the skeleton (1) adopts a flexible bellows, aluminum alloy, titanium alloy, coil spring or copper wire bundle structure.

[0011] Preferably, the width of the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) is w, the thickness is t, and the gap g between adjacent tapes is:

[0012] g=w+δ

[0013] Where δ is the process gap.

[0014] Preferably, the insulating material (4) is a strip structure with a width of 20-30 mm. When winding, each layer of the insulating material (4) is not overlapped, and adjacent layers are symmetrically staggered and pressed. At least two layers are wound, and the tension of the insulating material (4) during winding is controllable.

[0015] Preferably, the negative polarity superconducting tape group (3) is wound and embedded in the gap reserved by the positive polarity superconducting tape group (2), and the negative polarity superconducting tape group (3) and the positive polarity superconducting tape group (2) are at the same radial position in the radial direction.

[0016] Preferably, the same insulating material with the same thickness as the insulating material (4) is wound on the outside of the negative polarity superconducting tape group (3) in a tight wrapping manner with tension.

[0017] Preferably, the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) are regularly arranged radially outward to form multiple sets of superconducting tape combinations, and multiple operating modes of the superconducting DC cable are realized by changing the external electrical topology:

[0018] Operation mode 1: the lead terminals of the positive polarity superconducting tape group (2) in different sets of superconducting tape combinations are led out together, and the lead terminals of the negative polarity superconducting tape group (3) in different sets of superconducting tape combinations are led out together;

[0019] Operation mode 2: All lead-out terminals of the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) in all sets of superconducting tape combinations are led out together, and the lead-out terminals are short-circuited on the left and right sides to form a monopolar cable;

[0020] Operation mode 3: each lead-out terminal of the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) in all sets of superconducting tape combinations is led out separately;

[0021] Operation mode 4: the lead-out terminal of the positive polarity superconducting tape group (2) and the lead-out terminal of the negative polarity superconducting tape group (3) in each set of superconducting tape combinations are led out together;

[0022] Operation mode 5: After measuring the IC current of each outgoing unit by the four-lead method, the configuration combines the high-current positive electrode superconducting tape group with the low-current positive electrode superconducting tape group.

[0023] Preferably, in any set of superconducting tape combinations, the ones close to the cable skeleton are the inner superconducting tape group, and the ones far away from the cable skeleton are the outer superconducting tape group;

[0024] The inner superconducting tape group and the outer superconducting tape group in any set of superconducting tape combinations are both equipped with positive electrodes;

[0025] In any set of superconducting tape combinations, the inner superconducting tape group is configured with a positive electrode, and the outer superconducting tape group is configured with a negative electrode;

[0026] The positive and negative electrodes in the same layer of any set of superconducting tape combinations are arranged alternately, and the positive electrode of the inner superconducting tape group corresponds to the positive electrode of the outer superconducting tape group, and the negative electrode of the inner superconducting tape group corresponds to the negative electrode of the outer superconducting tape group.

[0027] In any set of superconducting tape combinations, the positive and negative electrodes in the same layer are alternately configured, with the positive electrode of the inner superconducting tape group corresponding to the negative electrode of the outer superconducting tape group, and the negative electrode of the inner superconducting tape group corresponding to the positive electrode of the outer superconducting tape group.

[0028] Preferably, the radial magnetic field of the low-voltage bipolar superconducting cable is uniformly distributed in the cable, or the radial magnetic field is constrained to be symmetrically distributed near the conductor, or the radial magnetic field is axially symmetrically distributed with the cable as the center, or the radial magnetic field is constrained to a small scale near the superconducting cable. In various configurations, the current passing through a single superconducting tape has the same magnitude and amplitude.

[0029] It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that the present invention proposes a low-voltage bipolar superconducting cable configuration design, which can realize multiple operating modes by changing the external electrical topology, thereby improving the application adaptability, flexibility and reliability of the superconducting DC cable.

[0030] Additional aspects and advantages of the present invention will be set forth in part in the following description, will become apparent from the following description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a superconducting tape and insulation arrangement method for a low-voltage bipolar superconducting cable provided in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of a low-voltage bipolar superconducting cable terminal lead-out structure provided by an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of an optional configuration mode of a low-voltage bipolar superconducting cable provided in an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of radial magnetic field distribution of a low-voltage bipolar superconducting cable under different configurations provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0037] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or couplings. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.

[0038] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention pertains. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such herein, will not be interpreted in an idealized or overly formal sense.

[0039] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0040] A schematic diagram of a superconducting tape and insulation arrangement method for a low-voltage bipolar superconducting cable provided by an embodiment of the present invention is shown in FIG. Figure 1 shown. Figure 1 The cross-sectional structure of the low-voltage bipolar superconducting cable of the present invention is given, which includes a cable skeleton 1, a positive polarity superconducting tape group 2, a negative polarity superconducting tape group 3 and an insulating material 4.

[0041] The skeleton 1 preferably adopts a flexible bellows structure, and the material is preferably 304 stainless steel, 304L stainless steel, or 316 stainless steel, which have good mechanical properties at low temperatures. In applications where weight is important, aluminum alloy or titanium alloy can also be used. In applications where higher thermal stability is required, coil springs, fine copper wire bundles, etc. can also be used.

[0042] The positive polarity superconducting tape group 2 and the negative polarity superconducting tape group 3 use the same tape specifications, with a width of w and a thickness of t. The positive polarity superconducting tape group 2 and the negative polarity superconducting tape group 3 are arranged on the skeleton 1 in a centrosymmetrical manner, and the gap g between adjacent tapes is:

[0043] g=w+δ

[0044] Among them, δ is the process gap, which is generally taken as w×(10-25)%, but cannot be less than 1mm.

[0045] The insulating material 4 is wound on the positive polarity superconducting tape group. The insulating material is generally selected from PPLP (polypropylene laminated paper) with good electrical and mechanical properties at low temperatures, or electrical kraft paper, polyimide film, etc. The insulating material is generally cut into strips with a width of 20-30 mm, preferably 25 mm. During winding, each layer is not overlapped, and adjacent layers are symmetrically staggered and pressed, and at least 2 layers are wound. The actual number of winding layers is determined according to the insulation strength, but the total thickness cannot exceed 0.5 mm. The tension of the insulating material tape during winding should be controllable to ensure that the insulating paper is in a tight state after the negative polarity tape group 3 is embedded in the gap of the positive polarity tape group.

[0046] The winding requirement of the negative polarity superconducting tape group 3 is to be embedded in the gap reserved by the positive polarity superconducting tape group 2. At this time, the negative polarity superconducting tape group 3 and the positive polarity superconducting tape group 2 are approximately at the same radial position.

[0047] In some application scenarios, the skeleton 1 is required to be at zero potential. One or two layers of insulating material 4 may be wound between the skeleton 1 and the positive polarity superconducting tape group 2 to achieve potential isolation.

[0048] On the outside of the negative polarity superconducting tape group 3, the same insulating material ( Figure 1 If there is no other superconducting tape group outside, the insulation material should be thickened by 20%.

[0049] Figure 1 The superconducting tapes in both positive polarity superconducting tape group 2 and negative polarity superconducting tape group 3 have certain winding angles, which are determined based on considerations such as flexible bending performance and economic efficiency. The winding angles are not a key technical point of the present invention and will not be discussed in detail here.

[0050] Figure 1 Only the positive polarity and negative polarity superconducting tape groups at the same radial distance are shown. More sets of superconducting tape combinations can be arranged in a regular order outward in the radial direction, which will not be described in detail here.

[0051] Figure 2The figure shows a schematic diagram of the lead-out structure of a low-voltage bipolar superconducting cable terminal according to an embodiment of the present invention. This figure uses a superconducting DC cable with two radially arranged positive and negative poles as an example; insulation treatments (such as stress cones) are not shown. Terminal a represents the lead-out terminal for the positive polarity superconducting tape group 2 of the first superconducting tape group, terminal b represents the lead-out terminal for the negative polarity superconducting tape group 3 of the first superconducting tape group, terminal a' represents the lead-out terminal for the positive polarity superconducting tape group 2' of the second superconducting tape group, and terminal b' represents the lead-out terminal for the negative polarity superconducting tape group 3' of the second superconducting tape group. Terminal a, for example, is typically made of bronze with a silver-plated surface. All the tapes of superconducting tape group 2 are connected, typically by soldering. Furthermore, the current leads are connected and then led out, typically by crimping with bolts.

[0052] The low-voltage bipolar superconducting cable proposed in the embodiment of the present invention realizes various operation modes of the superconducting DC cable by respectively leading out the positive and negative polarity superconducting tape groups at the terminals, thereby changing the external electrical topology.

[0053] Operation mode 1: The lead terminal a of the positive polarity superconducting tape group 2 of the first set of superconducting tape combinations is jointly led out with the lead terminal a' of the positive polarity superconducting tape group 2' of the second set of superconducting tape combinations, and the lead terminal b of the negative polarity superconducting tape group 3 of the first set of superconducting tape combinations is jointly led out with the lead terminal b' of the negative polarity superconducting tape group 3' of the second set of superconducting tape combinations, providing a larger current and well realizing the standard application of the coaxial cable.

[0054] Operation mode 2: The lead terminals a, a', b, and b' of the superconducting tape group are led out together and short-circuited on the left and right sides to form a monopolar cable. This achieves a self-cancelling effect of the magnetic field during power transmission while retaining the simplicity of a monopolar cable.

[0055] Operation mode 3: The lead-out terminal a of the positive polarity superconducting tape group 2 of the first set of superconducting tape combinations is led out separately, the lead-out terminal b of the negative polarity superconducting tape group 3 of the first set of superconducting tape combinations is led out separately, and the lead-out terminals of other superconducting tape groups are also led out separately. Different lead-out terminals can provide different users, providing higher adaptability to users with different electricity needs.

[0056] Operation mode 4: The lead-out terminal a of the positive polarity superconducting tape group 2 of the first set of superconducting tape combinations is led out together with the lead-out terminal b of the negative polarity superconducting tape group 3 of the first set of superconducting tape combinations. The lead-out terminals of the superconducting tape group of the second set of superconducting tape combinations are also led out in this way, realizing power supply in multiple traditional coaxial bipolar cable modes. The lead-out of the superconducting tape group of each set of superconducting tape combinations can be provided to users as a separate traditional coaxial bipolar cable.

[0057] Operation Mode 5: This cable configuration also features a lead-out method for specific situations. During the cable laying and winding process, some tapes may be damaged, resulting in the Ic current of the positive polarity superconducting tape group 2 of the first superconducting tape combination being greater than the Ic current of the positive polarity superconducting tape group 2' of the second superconducting tape combination. After measuring the IC (critical current) of each lead-out unit using the four-lead method, a high-current positive superconducting tape group can be flexibly combined with a low-current positive superconducting tape group to achieve more balanced power transmission in each section and avoid a significant drop in power transmission capacity due to damage to one pole.

[0058] In summary, the new bipolar cable has extremely strong flexibility in the lead-out method according to the strength of the applied current, the external magnetic field environment, and the characteristics of user needs, which greatly improves the reliability and stability of the bipolar superconducting cable. At the same time, it also has the characteristics of large capacity, high transmission density, low carbon and environmental protection, and can cope with complex urban power transmission conditions.

[0059] Figure 3 The figure shows a schematic diagram of an optional configuration mode for a low-voltage bipolar superconducting cable according to an embodiment of the present invention. This example uses a superconducting DC cable with a radially distributed superconducting tape assembly as an example. Within any superconducting tape assembly, the tape closest to the cable frame is the inner superconducting tape assembly, while the tape farther from the cable frame is the outer superconducting tape assembly.

[0060] Figure 3 (i) shows that both the inner superconducting tape group and the outer superconducting tape group of the superconducting tape group of any set of superconducting tape combinations are equipped with positive electrodes.

[0061] Figure 3 (ii) shows that the inner superconducting tape group of any set of superconducting tape combinations is configured with a positive electrode, and the outer superconducting tape group is configured with a negative electrode.

[0062] Figure 3 (iii) shows the same layer of the superconducting tape group of any set of superconducting tape combinations, with the positive and negative electrodes of the inner superconducting tape group corresponding to the positive electrodes of the outer superconducting tape group, and the negative electrodes of the inner superconducting tape group corresponding to the negative electrodes of the outer superconducting tape group.

[0063] Figure 3 (iv) shows the positive and negative alternating configuration of the same layer of the superconducting tape group of any set of superconducting tape combinations, where the positive electrode of the inner superconducting tape group corresponds to the negative electrode of the outer superconducting tape group, and the negative electrode of the inner superconducting tape group corresponds to the positive electrode of the outer superconducting tape group.

[0064] Figure 3The superconducting DC cable configuration shown in (i) has four positive lead terminals connected to the superconducting tape assembly of two sets of superconducting tapes. This configuration is suitable for separate lead terminals in Mode 3, which can be used to power different users. It is also suitable for flexible lead terminals based on Ic current in Mode 5. Figure 3 (ii) Figure 3 (iii) Figure 3 The superconducting DC cable configuration mode shown in (iv) can lead out two positive lead terminals and two negative lead terminals in the superconducting tape groups of the two sets of superconducting tape combinations, and is applicable to the above five different modes.

[0065] Figure 4 The figure shows the radial magnetic field distribution of the low-voltage bipolar superconducting cable in different configurations according to the embodiment of the present invention. The magnitude of the current flowing through a single superconducting tape is the same in the four configurations.

[0066] Figure 4 (i) shows Figure 3 (i) The magnetic field distribution in this configuration mode has a certain impact on the outside world, failing to achieve self-shielding. In this case, due to the lack of a superconducting shielding layer, the external magnetic field is distributed axisymmetrically around the cable, with the largest amplitude of the various configurations. This makes it suitable for corridors with low sensitivity to magnetic fields. However, this configuration can save half the superconducting tape, resulting in better economics.

[0067] Figure 4 (ii) is shown as Figure 3 (ii) Magnetic field distribution in the configuration mode: the magnetic field is confined near the conductor and has little impact on the outside world.

[0068] Figure 4 (iii) is shown as Figure 3 (iii) Magnetic field distribution in the configuration pattern: This configuration of positive and negative poles also effectively confines the magnetic field and achieves uniform distribution within the cable, resulting in superior spatial optimization of the magnetic field. In this case, the alternating spatial arrangement of positive and negative poles confines the magnetic field to a small scale near the superconducting cable, thereby reducing its external impact. However, due to the large radial component of the magnetic field near the superconducting tape, this reduces the critical current value of the superconducting tape, thereby affecting the superconducting tape's maximum current carrying capacity.

[0069] Figure 4 (iv) is shown as Figure 3 (iv) The magnetic field distribution of the configuration mode is not only confined to a symmetrical distribution near the conductor, but also Figure 4 (ii) with Figure 4 (iii) The magnetic field strength is further reduced.

[0070] By combining Figure 2Different modes of the positive and negative polarity groups at the terminals, Figure 3 Optional configuration modes of medium and low voltage bipolar superconducting cables Figure 4 The final superconducting cable is determined by the magnetic field distribution corresponding to each optional configuration mode, which fully demonstrates the high flexibility of this superconducting cable.

[0071] In summary, the low-voltage bipolar superconducting cable of the present invention can flexibly implement multiple operating modes by changing the external electrical topology, and achieve optimized current, magnetic field and redundancy configuration in different application scenarios or different operating conditions, thereby improving the application adaptability, flexibility and reliability of the superconducting DC cable.

[0072] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0073] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, refer to the partial description of the method embodiments. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. A person of ordinary skill in the art can understand and implement it without making any creative efforts.

[0074] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A low-voltage bipolar superconducting cable, characterized in that: include: A cable skeleton (1), a positive polarity superconducting tape group (2), a negative polarity superconducting tape group (3) and an insulating material (4); The positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) are both arranged on the skeleton (1) in a centrally symmetrical manner, and the insulating material (4) is wound on the positive polarity superconducting tape group (3). The tapes used in the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) are of the same specification, and the gaps between adjacent tapes are fixed.

2. The low-voltage bipolar superconducting cable according to claim 1, characterized in that: The skeleton (1) adopts a flexible bellows, aluminum alloy, titanium alloy, spiral spring or copper wire bundle structure.

3. The low-voltage bipolar superconducting cable according to claim 1, characterized in that: The width of the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) is w, the thickness is t, and the gap g between adjacent tapes is: g=w+δ Where δ is the process gap.

4. The low-voltage bipolar superconducting cable according to claim 1, characterized in that: The insulating material (4) is a strip-shaped structure with a width of 20-30 mm. When winding, each layer of the insulating material (4) is not overlapped, and adjacent layers are symmetrically staggered and pressed. At least two layers are wound. The tension of the insulating material (4) during winding is controllable.

5. The low-voltage bipolar superconducting cable according to claim 1, characterized in that: The negative polarity superconducting tape group (3) is wound and embedded in the gap reserved by the positive polarity superconducting tape group (2), and the negative polarity superconducting tape group (3) and the positive polarity superconducting tape group (2) are located at the same radial position in the radial direction.

6. The low-voltage bipolar superconducting cable according to claim 1, characterized in that: On the outside of the negative polarity superconducting tape group (3), the same insulating material with the same thickness as the insulating material (4) is wound in a tight wrapping manner with tension.

7. The low-voltage bipolar superconducting cable according to any one of claims 1 to 6, characterized in that: The positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) are regularly arranged radially outward to form multiple sets of superconducting tape combinations, and multiple operating modes of the superconducting DC cable are realized by changing the external electrical topology: Operation mode 1: the lead terminals of the positive polarity superconducting tape group (2) in different sets of superconducting tape combinations are led out together, and the lead terminals of the negative polarity superconducting tape group (3) in different sets of superconducting tape combinations are led out together; Operation mode 2: All lead-out terminals of the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) in all sets of superconducting tape combinations are led out together, and the lead-out terminals are short-circuited on the left and right sides to form a monopolar cable; Operation mode 3: each lead-out terminal of the positive polarity superconducting tape group (2) and the negative polarity superconducting tape group (3) in all sets of superconducting tape combinations is led out separately; Operation mode 4: the lead-out terminal of the positive polarity superconducting tape group (2) and the lead-out terminal of the negative polarity superconducting tape group (3) in each set of superconducting tape combinations are led out together; Operation mode 5: After measuring the IC current of each outgoing unit by the four-lead method, the configuration combines the high-current positive electrode superconducting tape group with the low-current positive electrode superconducting tape group.

8. The low-voltage bipolar superconducting cable according to claim 7, characterized in that: In any set of superconducting tape combinations, the ones close to the cable skeleton are the inner superconducting tape group, and the ones far away from the cable skeleton are the outer superconducting tape group; The inner superconducting tape group and the outer superconducting tape group in any set of superconducting tape combinations are both equipped with positive electrodes; In any set of superconducting tape combinations, the inner superconducting tape group is configured with a positive electrode, and the outer superconducting tape group is configured with a negative electrode; The positive and negative electrodes in the same layer of any set of superconducting tape combinations are arranged alternately, and the positive electrode of the inner superconducting tape group corresponds to the positive electrode of the outer superconducting tape group, and the negative electrode of the inner superconducting tape group corresponds to the negative electrode of the outer superconducting tape group. In any set of superconducting tape combinations, the positive and negative electrodes in the same layer are alternately configured, with the positive electrode of the inner superconducting tape group corresponding to the negative electrode of the outer superconducting tape group, and the negative electrode of the inner superconducting tape group corresponding to the positive electrode of the outer superconducting tape group.

9. The low-voltage bipolar superconducting cable according to claim 8, characterized in that: The radial magnetic field of the low-voltage bipolar superconducting cable is uniformly distributed within the cable, or the radial magnetic field is confined to be symmetrically distributed near the conductor, or the radial magnetic field is axially symmetrically distributed with the cable as the center, or the radial magnetic field is confined to a small scale near the superconducting cable. Under various configurations, the current flowing through a single superconducting tape has the same magnitude and amplitude.

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