Welded Aluminum Conductor Joints for Low-Resistance Cable Accessories

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Solution Overview

Problem

High power cables experience overheating due to poor contact resistance, especially in prefabricated cable joints and terminations, leading to breakdowns and financial damage, which is exacerbated by the intrinsic properties of aluminum conductors and inadequate manufacturing techniques.

Innovation Solution

A method involving the electrical welding of conductors followed by the placement of a metal sleeve between the welded conductor and the cable insulation to minimize air traps and enhance contact, reducing the risk of overheating by creating an ideal contact point with improved oxidation and mechanical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional connection methods (e.g., ferrule connectors) are used for aluminum conductors, then the assembly is easier to manufacture, but contact resistance increases leading to overheating

Engineering Contradiction:
Improveease of manufactureVSAvoidcontact resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces mechanical connection systems (ferrule connectors, compression joints) with welding technology to join aluminum conductors. This substitution eliminates the mechanical contact interface that causes high contact resistance and overheating, creating a metallurgical bond with superior electrical and thermal conductivity while maintaining ease of manufacture through automated welding processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental connection parameter from mechanical contact to metallurgical fusion through welding. This parameter change transforms the contact resistance from high (mechanical) to low (metallurgical), eliminating overheating issues while preserving manufacturing efficiency through standardized welding procedures for aluminum conductors.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If aluminum conductors are used in high power cables, then weight and cost are reduced, but contact resistance increases causing overheating

Engineering Contradiction:
ImproveweightVSAvoidcontact resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies welding technology specifically to aluminum conductors to replace mechanical connection systems. This resolves the inherent problem of aluminum's oxide layer and softness that cause poor mechanical contacts, while preserving aluminum's advantages of low weight and cost-effectiveness for high power cable applications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If mechanical connectors are used for conductor connections, then installation is simpler, but oxidation and poor electrical contact occur

Engineering Contradiction:
Improveease of operationVSAvoidelectrical contact
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical connectors with welding to eliminate oxidation-related contact resistance problems. The welded joint creates a continuous metallurgical bond that is immune to oxidation, providing superior electrical contact while maintaining operational simplicity through standardized welding procedures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method effectively reduces or eliminates overheating in high voltage cable accessories by improving contact resistance and mechanical stability, ensuring reliable operation and preventing financial losses associated with cable failures.

Implementation Method 1

electrically connecting the first and second conductors by welding them together

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4297209A1Method for connecting conductors in a prefabricated cable accessory
Publication Date: 2023.12.27 NKT HV CABLES AB
  • EP4297209A1 patent drawingFigure 1a~2
  • EP4297209A1 patent drawingFigure 3a~4
  • EP4297209A1 patent drawingFigure 5

AI summary

A method is disclosed for connecting a first and a second conductor for use in a prefabricated cable accessory. The method comprises electrically connecting the first and second conductors by welding them together and filling a space between an outer surface of the welded conductor and an outer surface of a cable insulation of the first and second conductors by arranging a metal sleeve therebetween.