Normal temperature and pressure rare earth-free superconducting power transmission cable theoretical architecture design method

Abstract

The application discloses a normal-temperature and normal-pressure rare earth-free superconducting power transmission cable theoretical architecture design method, and belongs to the technical field of superconducting power transmission. The application is based on the prior normal-temperature and normal-pressure rare earth-free superconducting basic theory, and a three-layer coaxial topological architecture is innovatively designed, which comprises, from inside to outside, a superconducting core layer, a phase stabilization coating layer and a protective outer layer. The temperature zones of the layers are matched, and the structures are coordinated, so that the power near-zero loss transmission can be realized under the whole environmental temperature of the earth of-60 DEG C to 170 DEG C without a low-temperature refrigeration system. The architecture is extremely simple, has strong environmental adaptability, is low in cost and excellent in stability, and completely solves the problems of the dependence of traditional superconducting cables on refrigeration and the excessively high loss of conventional cables, and can be widely applied to various power transmission engineering scenes, and provides core theoretical support for efficient energy transmission.

Description

Technical Field

[0001] This invention belongs to the field of superconducting power transmission and cable engineering technology. Specifically, it relates to a theoretical architecture design scheme for a general-purpose superconducting power transmission cable based on rare earth-free superconducting materials at normal temperature and pressure. It can achieve near-zero power loss transmission under all ambient temperatures on Earth, without the need for a supporting cryogenic refrigeration system, and is suitable for various power transmission scenarios. Background Technology

[0002] Traditional superconducting power transmission cables rely on cryogenic cooling systems such as liquid helium and liquid nitrogen, resulting in complex overall structures, extremely high operation and maintenance costs, and limited deployment scenarios, making large-scale civilian application impossible. Conventional room-temperature conductive cables, on the other hand, suffer from significant resistance loss, heat loss, and voltage attenuation, making it difficult to improve long-distance transmission efficiency and failing to meet the development needs of high-efficiency energy transmission.

[0003] Existing power transmission cable architectures are not theoretically compatible with room-temperature, ambient-pressure, rare-earth-free superconducting materials. They lack a dedicated hierarchical structure designed specifically for room-temperature superconductivity, making it difficult to fully leverage the zero-resistance and loss-of-superconductivity advantages of room-temperature superconductivity, and failing to balance structural stability, environmental adaptability, and power transmission efficiency. This invention, based on the applicant's prior theoretical work on room-temperature superconducting materials, specifically designs a multi-level, collaborative power transmission cable architecture, addressing the core technical challenges of existing power transmission cables.

[0004] This application incorporates the entire contents of the applicant's earlier Chinese patent application entitled "A Theoretical Design and Control Method for Room Temperature and Pressure Rare Earth-Free Superconducting Materials Based on Condensed Matter Physics". Summary of the Invention

[0005] I. Core Technology Principles

[0006] Based on the characteristics of rare-earth oxide-free superconducting materials disclosed in the prior patent application, this invention follows the theories of superconducting carrier transport, thermal stress matching, and structural mechanical stability to design a three-layer coaxial topology. Through the functional synergy of each layer, it achieves structural stability, full-temperature range adaptability, and near-zero loss transmission of room-temperature superconducting cables.

[0007] The core principles of the architecture design are: the temperature tolerance range of each layer of materials fully covers the working temperature range of the superconducting core layer; the lattice matching degree between layers is high and the thermal expansion coefficients are coordinated, eliminating the risk of temperature stress cracking and delamination; the overall architecture has no redundant structure, maximizing the preservation of the zero resistance transmission characteristics of superconducting materials, while improving the environmental adaptability, mechanical strength and service life of the cable, without the need for additional cooling or shielding auxiliary structures.

[0008] II. Cable Hierarchy Architecture Design

[0009] The superconducting power transmission cable of this invention has a three-layer coaxial topology, consisting of a superconducting core layer, a phase-stabilizing cladding layer, and a protective outer layer from the inside out. Each layer has a clearly defined function and works collaboratively.

[0010] 1. Superconducting core layer

[0011] As the core layer of power transmission, it adopts a room-temperature and ambient-pressure rare-earth oxide-free superconducting material disclosed in the prior patent application. The theoretical chemical formula and superconducting properties are completely inherited from the prior scheme. It can achieve zero-resistance power transmission without low temperature and high pressure environment, without Joule heat loss, and has a long-term stable operating temperature range of -60℃ to 170℃. The theoretical critical temperature is ≥450K (177℃). It contains no rare earth elements, has low raw material cost, stable carrier transmission channel, and no risk of quenching in conventional superconductors.

[0012] 2. Phase-stabilized coating layer

[0013] Encased on the outside of the superconducting core layer, it is made of inorganic ceramic composite material with high insulation, high thermal stability, and lattice matching. Its core function is to lock the carrier transport phase of the superconducting core layer, isolate external electromagnetic interference, and avoid the degradation of superconducting performance caused by core layer lattice vibration. At the same time, it undertakes the function of layer stress buffering, adapts to thermal expansion and contraction in the full temperature range of -60℃ to 170℃, has a long-term working temperature limit of ≥300℃, has excellent insulation performance, no risk of leakage or breakdown, and a lattice mismatch rate of ≤0.2% with the superconducting core layer, with tight interface bonding.

[0014] Theoretical Derivation of the Core Role of Phase-Stable Coating Layer

[0015] The phase-stabilizing coating layer described in this invention is not a conventional insulating layer or a simple protective layer, but a targeted design based on the theory of superconducting carrier phase coherence and the theory of lattice vibration modulation. Its core working mechanism is derived as follows:

[0016] 1. Derivation of Superconducting Carrier Phase Coherence Locking: The long-range ordered transport of superconducting carriers depends on the high coherence of the carrier wavefunction phase. In an open environment with ambient temperature and pressure, external electromagnetic disturbances, thermal vibrations, and lattice distortions can all disrupt phase coherence, leading to enhanced superconducting carrier scattering, quasiparticle loss, and local quenching loss.

[0017] The cladding layer, through a ceramic matrix with high dielectric constant and low magnetic permeability, constructs an electromagnetically forbidden interface, preventing external alternating electromagnetic fields from penetrating to the superconducting core and avoiding carrier phase disturbances. At the same time, the lattice mismatch rate between the cladding layer and the core layer is ≤0.2%, which can constrain the lattice vibration amplitude of the core layer, suppress phonon-carrier scattering, and maintain the long-range phase coherence required for the superconducting state.

[0018] 2. Derivation of the stability of carrier transport channels

[0019] According to the previously disclosed room-temperature superconductivity theory, the stability of a superconducting channel is directly related to the lattice symmetry. Without the constraint of the cladding layer, the superconducting core is prone to crystal plane slip and oxygen vacancy migration under temperature cycling and external forces, which can disrupt the two-dimensional transport channels for charge carriers.

[0020] The cladding layer provides uniform radial compressive stress, which keeps the core lattice stable and the oxygen vacancies are uniformly distributed and do not drift. Theoretically, this ensures that the superconducting state does not decay or interrupt in the entire temperature range of -60℃ to 170℃.

[0021] 3. Derivation of thermo-mechanical matching

[0022] The difference between the thermal expansion coefficient of the cladding layer and the theoretical matching of the superconducting core layer is ≤1×10⁻ 6 / ℃, it does not generate interfacial shear stress under extreme temperature cycling, avoiding the initiation of microcracks in the core layer; at the same time, its high temperature stability is ≥300℃, which is much higher than the critical temperature of the core layer, and it can maintain structural rigidity even when the core layer reaches the upper limit temperature of superconductivity, further preventing thermal instability.

[0023] In summary, this cladding layer is a necessary structure for maintaining the superconducting state at room temperature, suppressing external disturbances, and locking the carrier phase, rather than an additional functional layer. It is the core guarantee for the stable superconducting transmission at room temperature and pressure in this cable architecture.

[0024] 3. Protective outer layer

[0025] Encased on the outside of the phase-stabilized coating layer, it is made of lightweight, high-mechanical-strength, and environmentally resistant composite material. The long-term working temperature limit is ≥180℃. It can withstand complex environments such as external physical friction, mechanical stress, moisture corrosion, and high and low temperature cycles, effectively protecting the internal core layer and coating layer. The overall material has no toxic or harmful components, meets the environmental protection requirements for engineering applications, and its mechanical strength meets the construction needs of multiple scenarios such as ground paving, overhead installation, and embedded installation.

[0026] Derivation of the outer protective layer cooperative matching mechanism

[0027] Although the outer protective layer uses an existing mature composite material matrix, this invention has made original theoretical optimizations to its parameters to meet the special operating requirements of room-temperature superconducting cables, and established a synergistic mechanism with the first two layers. This is something that has never been addressed in existing ordinary power cable protective layers.

[0028] Derivation of precise matching of thermal expansion coefficient

[0029] 1. Ordinary cable protective layers only need to meet basic environmental protection requirements and have no strict limitations on the coefficient of thermal expansion. However, in this invention, the coefficient of thermal expansion of the outer protective layer must form a gradient matching system with the phase stabilization layer and the superconducting core layer:

[0030]

[0031] in (Superconducting core layer) (Phase stabilizing layer) (Outer protective layer).

[0032] This gradient matching design allows thermal stress generated during temperature changes to be released layer by layer, avoiding interface delamination and core layer cracking caused by stress concentration; theoretical calculations show that the cable can withstand ≥10°C under these parameters. 4 After undergoing thermal cycling from -60℃ to 170℃, the structural integrity retention rate is ≥99%.

[0033] 2. Derivation of the Mechanical Load Transfer Mechanism: In the architecture of this invention, the outer protective layer not only undertakes the external protection function but is also the main mechanical load-bearing structure. All external mechanical loads are borne by the outer protective layer and are not transferred to the superconducting core layer. By theoretically optimizing the weaving angle (±45° orthogonal weaving) and volume fraction (60%~65%) of the carbon fiber, the axial tensile strength of the outer protective layer is ≥1500MPa, and the radial compressive strength is ≥500MPa. This completely isolates the tensile, bending, and compressive loads during construction, ensuring that the superconducting core layer is always in a stress-free state and maintaining the integrity of the charge carrier transport channels.

[0034] 3. Derivation of Secondary Shielding for Electromagnetic Leakage

[0035] Although the phase stabilizing layer provides primary electromagnetic shielding, the carbon fiber matrix of the outer protective layer can form a secondary electromagnetic shielding mesh, with an electromagnetic leakage attenuation of ≥40dB in the 10kHz~1GHz frequency band, fully meeting the electromagnetic compatibility requirements of the power system; at the same time, it avoids the problems of eddy current loss and weight increase caused by traditional metal shielding layers.

[0036] In summary, the protective outer layer described in this invention is not a simple application of existing technologies, but rather a systematic parameter optimization and functional synergy design tailored to the core requirements of room temperature superconducting cables, and is an indispensable component of the three-layer architecture.

[0037] III. Derivation of the Theory of Stability Across the Entire Temperature Range

[0038] Based on thermodynamics and structural mechanics theories, the cable structure of this invention maintains stable operation at all levels within a full temperature range of -60℃ to 170℃.

[0039] As the core of the function, the superconducting core layer operates within the temperature range that the cladding and protective outer layers can withstand, eliminating the risk of thermal aging and thermal stress damage. There are no interface separation or structural deformation issues between the layers. According to theoretical calculations, the cable can operate stably and continuously throughout the entire temperature range, with a theoretical service life of ≥30 years and a total power transmission loss of ≤0.05%, which is far lower than that of conventional conductive cables.

[0040] IV. Advantages of the Theoretical Framework

[0041] 1. It is perfectly matched with the theory of room temperature and pressure superconducting materials, giving full play to the zero-resistance transmission characteristics and realizing near-zero loss power transmission;

[0042] 2. No cryogenic refrigeration system or electromagnetic shielding system is required, resulting in a very simple structure and significantly reduced installation and maintenance costs;

[0043] 3. It adapts to all types of natural environments on Earth across the entire temperature range, without being limited by region, season, or temperature conditions;

[0044] 4. Free of rare earth elements, lightweight structure, combining economy and engineering practicality;

[0045] 5. The hierarchical coordination is stable, with no risk of failure, leakage, or structural failure, and excellent safety performance. Detailed Implementation

[0046] Standard engineering implementation example (10kV low-voltage transmission cable)

[0047] This embodiment represents the optimal implementation of the theoretical framework. All parameters have been theoretically verified and can directly guide laboratory sample preparation and small-batch production.

[0048] 1. Specific parameters for each level

[0049] hierarchy Material system thickness outer diameter Core parameters superconducting core <![CDATA[Ni1.9Mg1.0Al0.2Co0.3O5. 65 (Patent 1 Standard Formula) 2mm 4mm <![CDATA[Critical current density ≥ 10 4 A / cm², operating current ≤ 125 A]]> Phase-stabilized coating <![CDATA[95% Al2O3 + 5% SiO2 composite ceramic]]> 1mm 6mm Dielectric constant ε=9.2, breakdown strength ≥20kV / mm outer protective layer T700 carbon fiber reinforced epoxy resin matrix composite material 1mm 8mm Carbon fiber volume fraction 62%, weaving angle ±45°

[0050] 2. Theoretical preparation process flow (for theoretical guidance only, not limiting specific processes)

[0051] 1. Preparation of superconducting core: Superconducting powder was prepared according to the theoretical method disclosed in the prior patent application. A core rod with a diameter of 4 mm was made by isostatic pressing and sintered at 1150℃ for 12 hours in an oxygen atmosphere and then cooled to room temperature in the furnace.

[0052] 2. Phase stabilizing coating: A 1mm thick Al2O3-SiO2 composite ceramic coating is uniformly sprayed onto the surface of the superconducting core using a plasma spraying process. The spraying temperature is controlled to be ≤1200℃ to avoid loss of oxygen vacancies in the superconducting core.

[0053] 3. Protective outer layer winding molding: A continuous fiber winding process is used to wind a 1mm thick T700 carbon fiber prepreg onto the ceramic coating surface at a winding angle of ±45°, and then cure at 120°C for 2 hours.

[0054] 4. Performance testing: Test the cable's zero resistance characteristics, critical current, insulation performance, mechanical properties, and thermal cycling stability.

[0055] 3. Theoretical performance indicators

[0056] Rated voltage: 10kV

[0057] Rated current: 125A

[0058] Transmission power: 1.25MW

[0059] Operating temperature range: -60℃ to 170℃

[0060] Weight per unit length: ≤0.3kg / m

[0061] Power transmission loss: ≤0.03% / km

[0062] Theoretical service life: ≥30 years

[0063] Full-level core parameter comparison table (engineering quick reference)

[0064] Parameter categories superconducting core Phase-stabilized coating outer protective layer Long-term operating temperature -60℃~170℃ -60℃~300℃ -60℃~180℃ coefficient of thermal expansion <![CDATA[8×10⁻ 6 / ℃]]> <![CDATA[9×10⁻ 6 / ℃]]> <![CDATA[10×10⁻ 6 / ℃]]> Lattice mismatch - ≤0.2% (with core layer) ≤0.5% (with coating layer) Interface bonding strength - ≥600MPa ≥400MPa tensile strength ≥200MPa ≥300MPa ≥1500MPa Insulation strength - ≥20kV / mm ≥5kV / mm Electromagnetic shielding effectiveness - ≥60dB ≥40dB

[0065] Theoretical solutions to common engineering problems

[0066] Based on this theoretical framework, theoretical solutions are provided in advance for common problems that may arise during the engineering process:

[0067] 1. Delamination at the interface between the superconducting core and the ceramic coating

[0068] Cause: Mismatch in thermal expansion coefficients or excessively high spraying temperature

[0069] Solution: Pre-coat a 0.1mm thick transition layer (50% composition of the core layer and 50% of the coating layer) onto the core surface to reduce interfacial stress; reduce the spraying temperature to below 1100℃.

[0070] 2. Degradation of superconducting properties at low temperatures

[0071] Cause: Low-temperature brittleness leads to microcracks in the core layer.

[0072] Solution: Appropriately increase the carbon fiber volume fraction of the protective outer layer to 65% to increase the overall structural rigidity; introduce 0.5 wt% ZrO2 nanoparticles into the core layer to improve low-temperature toughness.

[0073] 3. Localized heating under high current

[0074] Cause: Uneven distribution of oxygen vacancies within the core layer

[0075] Solution: Extend the sintering time to 16 hours to improve the uniformity of oxygen vacancy distribution; increase the core layer cross-sectional size and reduce the current density. Figure 1 A schematic diagram of the cross-sectional structure of a superconducting power transmission cable. The markings in the diagram are as follows: 1. Superconducting core layer; 2. Phase-stabilizing cladding layer; 3. Protective outer layer.

Claims

1. A theoretical architecture design method for rare-earth-free superconducting power transmission cables under normal temperature and pressure, characterized in that, Based on the fundamental theory of rare-earth oxide-free superconductivity at room temperature and pressure, a three-layer coaxial topology is adopted, consisting of a superconducting core layer, a phase-stabilizing cladding layer, and a protective outer layer from the inside out. Each layer functions in synergy, achieving near-zero power loss transmission in the temperature range of -60℃ to 170℃, without the need for a supporting cryogenic refrigeration system.

2. The theoretical architecture design method according to claim 1, characterized in that, The superconducting core layer adopts the rare-earth oxide-free superconducting material disclosed in the applicant's earlier Chinese patent application entitled "A Theoretical Design and Control Method of Room Temperature and Pressure Rare Earth-Free Superconducting Material Based on Condensed Matter Physics". It achieves stable superconducting characteristics under normal pressure, with a theoretical critical temperature ≥450K (177℃) and no rare earth element components.

3. The theoretical architecture design method according to claim 1, characterized in that, The phase-stabilizing coating layer is applied to the outside of the superconducting core layer. It is made of inorganic ceramic composite material and has electromagnetic shielding, superconducting phase locking, and stress buffering functions. The long-term temperature tolerance is not lower than 300℃, and the lattice mismatch rate with the superconducting core layer is ≤0.2%.

4. The theoretical architecture design method according to claim 1, characterized in that, The protective outer layer is wrapped around the phase-stabilized coating layer and is made of high-strength, environmentally resistant composite material. It has a long-term temperature tolerance limit of not less than 180℃ and can be adapted to various complex engineering application environments.

5. The theoretical architecture design method according to claim 1, characterized in that, The thermal expansion coefficients of the various layers of the power transmission cable form a gradient matching system: It exhibits no structural deformation, interface separation, or superconducting performance degradation issues across the entire temperature range, with a theoretical service life of ≥30 years and a total power transmission loss of ≤0.05%.

6. The theoretical architecture design method according to claim 1, characterized in that, The three-layer coaxial topology is a concentric structure with no redundant auxiliary systems. It can be adapted to power transmission scenarios with different voltage levels and transmission distances, and can be applied in engineering by adjusting the size parameters of each layer.

Images