Superconducting Cable With Conducting Layer for Fault Current
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Solution Overview
Problem
Conventional superconducting cables face issues with the physical rigidity of superconducting wires, which can break under tension or torsion stress, and have a large diameter due to the use of general metal conductors for fault current return paths, increasing the overall size and weight of the cable.
Innovation Solution
A superconducting cable design that includes a conducting layer made of a metal with current-carrying properties at room temperature added to the superconducting wires, connected in parallel with the former, to enhance mechanical rigidity and reduce the cross-sectional area of the former, using a brass material for the conducting layer and soldering with tin, lead, and silver solders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a former with large cross-sectional area is used to carry fault current, then the current-carrying capacity is improved, but the diameter and weight of the superconducting cable increase
Solution Approach 1:
The fault current path is segmented into multiple parallel paths: the former and the conducting layer. This segmentation allows the current-carrying capacity to be distributed across multiple smaller components rather than requiring one large former, thereby reducing the overall cable diameter and weight while maintaining reliability.
Solution Approach 2:
The patent uses a composite structure combining the former (traditional metal conductor) with the conducting layer (superconducting wire with metal coating). This composite approach allows the system to utilize both materials' properties: the former provides mechanical support and partial current carrying, while the conducting layer provides additional current carrying capacity with smaller cross-section, reducing overall cable weight.
2Ease of manufacture
If superconducting wires without conducting layer are used, then the manufacturing simplicity is improved, but the physical rigidity and resistance to tension/torsion deteriorate
Solution Approach 1:
The superconducting wire is constructed as a composite material with a core superconducting layer and an outer metal conducting layer. The metal coating (such as silver, copper, or aluminum) provides mechanical strength and rigidity to the otherwise fragile superconducting material, while the superconducting core maintains the electrical superconductivity properties. This composite structure enables the wire to withstand tension and torsion stresses during installation and operation.
3Strength
If the conducting layer is added to superconducting wires, then the mechanical rigidity is improved, but the device complexity increases
Solution Approach 1:
The conducting layer is merged with the superconducting wire structure, combining two functions into one component: the metal coating simultaneously provides mechanical protection (rigidity) and electrical conductivity (fault current path). This merging eliminates the need for separate protective sheathing or additional structural elements, thereby reducing overall device complexity despite the added layer.
4Area of stationary object
If the former cross-sectional area is reduced, then the cable diameter is reduced, but the fault current carrying capacity deteriorates
Solution Approach 1:
The fault current carrying function is segmented between two parallel paths: the reduced former and the conducting layer on the superconducting wires. By dividing the current carrying responsibility, the system can use a smaller former while maintaining total current capacity through the addition of the conducting layer, thus reducing cable diameter without sacrificing reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reinforces the physical rigidity of superconducting wires, diversifies the shunt path for fault current, and reduces the diameter and weight of the former, thereby minimizing the size and production costs of the superconducting cable.
Implementation Method 1
a conducting layer formed of a metal having a current-carrying property at room temperature is provided on opposite surfaces of each of the superconducting wires
Implementation Method 2
A superconducting wire has an electric resistance which converges close to zero at a certain temperature and has a high power transfer capability even at a low voltage
Implementation Method 3
a cooling method performed using a refrigerant such as nitrogen and/or an insulation method of forming a vacuum layer is used to form and maintain an extremely low-temperature environment
Data Source
AI summary
A superconducting cable includes a core part, in which the core part includes a former including a plurality of copper wires, a superconducting conductor layer including a plurality of superconducting wires connected in parallel to each other, an insulating layer, and a superconducting shield layer including a plurality of superconducting wires are sequentially arranged. A conducting layer formed of a metal having a current-carrying property at room temperature is provided on opposite surfaces of each of the superconducting wires of the superconducting conductor layer to reinforce mechanical rigidity of each of superconducting wires of the superconducting conductor layer, and the former has a cross-sectional area which is smaller than that of a former of a superconducting cable in which the conducting layer is not added to superconducting wires and which is designed on an assumption that all fault current flows to the former.