Superconducting Cable Former Structure for Cryogenic Thermal Contraction
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Solution Overview
Problem
Superconducting power cables face issues with axial and radial contraction at cryogenic temperatures, leading to stress on the former and superconducting material due to thermal contraction, which existing solutions do not adequately address.
Innovation Solution
A superconducting power cable design featuring an axially stretchable core with elongated outer elements wound helically around it, where the core and outer elements are made of materials with different thermal contraction rates, allowing for axial stress reduction and maintaining radial position, thereby compensating for thermal contraction without increasing the cable's length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the former is made longer to accommodate axial contraction at cryogenic temperature, then axial stress on the former is reduced, but the cross-section of the superconducting power cable becomes larger
Solution Approach 1:
The patent changes the material parameters of the former by using a composite structure with materials having different thermal contraction characteristics. The core uses a material with high radial contraction (1-5%) while the outer elements use material with low thermal contraction, creating a former that contracts radially but maintains axial length, thus reducing axial stress without increasing cable cross-section.
Solution Approach 2:
The former is constructed as a composite structure with a core made of one material and outer elements made of another material with different thermal properties. This composite design allows the former to exhibit anisotropic thermal contraction behavior - high radial contraction to accommodate thermal shrinkage while maintaining axial length to reduce stress on cable terminations.
2Stability of the object's composition
If the former is fixed to cable terminations to provide structural support, then mechanical stability is improved, but thermal contraction stress increases at cryogenic temperature
Solution Approach 1:
The patent applies different material properties to different parts of the former - the core has high radial contraction capability while the outer elements have low thermal contraction. This local differentiation allows the former to be rigid axially (providing mechanical stability) while being flexible radially (accommodating thermal contraction), thus maintaining stability without excessive stress.
3Loss of energy
If the superconducting conductor layer is arranged tightly around the former to reduce AC losses, then electrical efficiency is improved, but stress on the superconducting material increases due to thermal contraction
Solution Approach 1:
The patent changes the thermal contraction parameters of the former by using composite materials, which indirectly affects the stress on the superconducting layer. By making the former contract radially rather than axially, the superconducting layer can be arranged tightly around the former at operating temperature without experiencing excessive tensile stress, thus reducing AC losses while maintaining structural integrity.
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
This design reduces axial length contraction, allowing for a more compact cable configuration and minimizing stress on the core, while maintaining radial stability and reducing AC losses through gapless superconducting conductor layers.
Implementation Method 1
the core comprises a first material and the elongated outer elements comprise a second material thermally contracting less than the first material at the operating temperature of the superconducting power cable
Implementation Method 2
the first material thus contract more in the axial and radial directions than the second material at the cryogenic temperature at which the superconducting power cable is operated
Implementation Method 3
an axially stretchable core, and a plurality of elongated outer elements wound helically around the core
Implementation Method 4
Due to the elongated outer elements being laid helically they will essentially maintain their radial position relative to the core after thermal contraction
Implementation Method 5
Superconducting power cables use superconducting material as conductor
Data Source
AI summary
A superconducting power cable having: a former including: an axially stretchable core, and a plurality of elongated outer elements wound helically around the core, wherein the core includes a first material and the elongated outer elements include a second material thermally contracting less than the first material at the operating temperature of the superconducting power cable; and a superconducting conductor layer arranged around the former.