Superconductive Cable Connection Using Coolant Insulation

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Solution Overview

Problem

The existing methods for electrically connecting superconductive cables are complex, time-consuming, and require significant effort, especially when connecting cables with multiple conductors, due to the need for restoring insulating layers and ensuring proper coolant flow in cryostats.

Innovation Solution

The method involves mechanically and electrically connecting the ends of superconductive cables in a parallel configuration within a cryostat housing, eliminating the need for insulating layers and allowing the coolant to serve as an insulator, thereby reducing the effort and complexity of the connection process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulating layers are restored after connecting superconductive conductors, then electrical insulation is maintained, but the connection process becomes complex and time-consuming

Engineering Contradiction:
Improveelectrical insulationVSAvoidconnection process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the insulating layer restoration step from the connection process by using the coolant itself as the insulating medium. The coolant surrounds the conductors in the housing, providing electrical insulation without requiring additional insulating material to be applied after connection, thereby eliminating the complex restoration process while maintaining electrical insulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coolant serves multiple functions: it cools the superconductive conductors to maintain superconductivity and simultaneously provides electrical insulation between the conductors. This multi-functionality eliminates the need for separate insulating layers, simplifying the connection process while maintaining both thermal and electrical requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If insulating layers are restored after connecting superconductive conductors, then electrical insulation is maintained, but the connection time increases significantly

Engineering Contradiction:
Improveelectrical insulationVSAvoidconnection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent removes the time-consuming insulating layer restoration step by using the coolant as the insulating medium. The coolant is already present in the housing during the connection process, eliminating the need to apply and cure insulating material, thereby significantly reducing connection time while maintaining electrical insulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The housing is pre-filled with coolant before the connection process begins. This preliminary preparation ensures that the insulating medium is already in place, allowing conductors to be connected without subsequent steps to apply insulating layers, thus saving time while ensuring insulation is maintained throughout the process.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If specialized personnel are used for connecting superconductive cables, then connection quality is ensured, but labor effort and cost increase

Engineering Contradiction:
Improveconnection qualityVSAvoidconnection effort
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the complex requirement for specialized personnel by simplifying the connection process itself. By eliminating the need to apply and restore insulating layers, the connection becomes a simpler mechanical and electrical connection that can be performed with standard procedures, reducing the need for highly specialized training while maintaining connection quality through the inherent insulation provided by the coolant.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If the wall thickness of restored insulation is increased, then electrical insulation is improved, but the cryostat dimensions increase and impede coolant flow

Engineering Contradiction:
Improveelectrical insulationVSAvoidcoolant flow efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The coolant serves dual functions: cooling the superconductive conductors and providing electrical insulation. Since the coolant is already present in sufficient quantity to fill the housing, it provides adequate insulation without requiring additional thick insulating layers that would reduce the coolant flow channel dimensions and impede coolant circulation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The coolant automatically provides the insulating function without requiring additional insulating material. The coolant surrounds the conductors in the housing, and its dielectric properties provide the necessary electrical insulation while maintaining the flow channels open for efficient heat removal, as the coolant itself is the insulating medium.

Inventive Principle:
Principle #25Self-service

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 approach significantly reduces the effort and time required for connecting superconductive cables, particularly those with multiple conductors, by eliminating the need for insulating material and simplifying the process, while maintaining efficient coolant flow and operational dimensions of the cryostat.

Implementation Method 1

they have electrical conductors made of a material which changes to the superconductive state at sufficiently low temperatures, with zero electrical DC resistance

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Implementation Method 2

Suitable coolants for all these materials are, for example, nitrogen, helium, neon and hydrogen or mixtures of these substances

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 3

Their conductors, freed from surrounding layers, are electrically conductively connected to one another at their end faces within the housing by an electrical contact element

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2819247B1Method for connecting two superconductive cables in a manner that conducts electricity
Publication Date: 2018.08.08 NEXANS SA
  • EP2819247B1 patent drawingFigure 1~5
  • EP2819247B1 patent drawingFigure 4~6

AI summary

A method for electrically connecting two superconducting cables is described, each cable having at least one superconducting conductor surrounded by a dielectric and an electrically effective shield arranged above the dielectric. The conductors and shields to be joined are first stripped of surrounding layers at the ends of both cables. The ends of the two cables (1, 2) are then arranged side by side and parallel to each other such that their free ends point in the same direction and are firmly connected to each other in this position.The conductors (5) of the two cables (1,2) on the one hand and their shields (7) on the other hand are electrically connected to each other by electrical contact elements (8,9) extending transversely to their axis direction and the two cable ends treated in this way are arranged together in a housing (10) of a cryostat when constructing a transmission line for electrical energy, which is supplied with a flowable coolant with insulating properties during operation of the transmission line.