Superconducting Cable Sliding Layer Prevents Abrasion
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Solution Overview
Problem
The existing superconducting cable systems face issues with metallic particle abrasion during relative movement between the cable and cryostat, leading to potential electrical disruptions and breakdowns, especially when the inner tube of the cryostat is corrugated, increasing abrasion and the risk of destruction at electrical field-exposed areas.
Innovation Solution
A sliding layer made of abrasion-resistant materials like bronze is applied around the conductor to prevent metal particle abrasion and reduce friction, ensuring no metal particles are generated during movement, and facilitating cable expansion and contraction within the cryostat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cable and cryostat are made of materials with lower abrasion resistance (e.g., copper, aluminum, stainless steel), then electrical conductivity and thermal performance are improved, but metallic particle abrasion increases during relative movement
Solution Approach 1:
A sliding layer made of abrasion-resistant material is introduced as an intermediary between the conductor and the corrugated cryostat tube. This sliding layer prevents direct contact and abrasion between the metal surfaces, stopping metallic particle generation while allowing necessary relative movement during thermal expansion and contraction.
Solution Approach 2:
The cable structure is enhanced by adding a composite sliding layer with different material properties (higher abrasion resistance) than the base conductor materials. This composite construction combines the electrical conductivity of copper/aluminum with the wear resistance of the sliding layer material.
2Strength
If the inner tube of the cryostat is corrugated to provide structural support, then mechanical strength is improved, but abrasion resistance during cable movement deteriorates
Solution Approach 1:
The sliding layer serves as a mediator between the corrugated cryostat tube and the cable, allowing the corrugation to provide structural support while preventing the corrugated surface from directly abrading the conductor during relative movement.
3Stability of the object's composition
If the cable is allowed to move freely during thermal expansion and contraction, then thermal stress is reduced, but metallic particle generation increases due to abrasion
Solution Approach 1:
The sliding layer enables free thermal expansion and contraction movements while preventing metallic particle generation by eliminating direct metal-to-metal contact during these movements.
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 effectively prevents metallic particle abrasion, reducing the risk of electrical disruptions and enhancing the system's reliability by minimizing friction and wear, thus ensuring stable operation and extended lifespan of the cable.
Implementation Method 1
A superconductive cable has electrical conductors made of a special material that becomes superconductive at sufficiently low temperatures. As a result, the electrical resistance of a correspondingly constructed conductor approaches zero.
Implementation Method 2
A superconducting cable is cooled from room temperature to a temperature of, for example, 73 K during operation of the system.
Implementation Method 3
The cable shrinks by about 0.3%. A 600 m long cable therefore shrinks by about 1.8 m.
Implementation Method 4
The conductor of the cable, which is made of electrically highly conductive material, is largely protected against abrasion by the overlay. In the event of a relative movement of the cable and the cryostat, therefore, no metal particles are abraded from the same.
Data Source
Figure 1~2
AI summary
A system with a superconducting cable (KA) is described, consisting of a superconducting inner conductor (1), a screen arranged concentrically to the inner conductor, and a dielectric (3) located between the inner conductor and the screen. The screen (S) is constructed of a superconducting part (4) and a surrounding part (5) made of electrically conductive material. The screen (S) is enclosed by a cryostat (KR), which consists of two concentric stainless steel tubes (6, 7) separated by an evacuated space (8) and superinsulated. The cryostat includes an intermediate space (9) for the passage of a liquid cooling medium.To protect against abrasion of metallic parts, the surface of the shield (S) of the cable (KA) enclosed by the cryostat (KR) and/or the cryostat (KR) is provided on its inner surface all around with a sliding layer (10) made of an abrasion-resistant material with a lower coefficient of friction than steel.