Lead-Free Power Cable Water Barrier With Seam Defect Sealing
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Solution Overview
Problem
High voltage power cables face issues with lead-based water barriers due to their weight, environmental concerns, and high risk of failure in long cables, particularly due to welding defects like pinholes in the metal seams.
Innovation Solution
A non-leaded metallic screen is wrapped around the cable core and conductors, with identified welding defects sealed by an additional metal layer deposited using additive manufacturing techniques, such as cold spray or laser powder deposition, to create a robust and watertight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead-based water barrier is used, then water tightness is achieved, but weight increases significantly and environmental harm occurs
Solution Approach 1:
The patent changes the material parameter from lead to aluminum, which has lower density (approximately one-third the density of lead), thereby reducing cable weight while maintaining water barrier functionality. This material substitution directly addresses the weight concern without compromising the water tightness requirement.
2Reliability
If lead-based water barrier is used, then water tightness is achieved, but environmental harm and neurotoxicity occur
Solution Approach 1:
The patent extracts and removes the harmful lead material from the water barrier system, replacing it with environmentally benign aluminum. This elimination of toxic substances directly addresses the environmental harm and neurotoxicity issues while preserving the essential water tightness function.
3Object-generated harmful factors
If long cables with welded metallic screens are produced, then lead-free construction is achieved, but production defects like pinholes in welding seams occur
Solution Approach 1:
The patent applies preliminary protective action by depositing an additional metal layer over the welding seams before the cable is put into service. This preventive coating seals potential pinholes and welding defects in advance, ensuring water tightness is maintained even when welding imperfections occur during manufacturing of long cables.
4Object-generated harmful factors
If welded metallic screens are used in long cables, then lead-free construction is achieved, but reliability decreases due to undetected welding defects
Solution Approach 1:
The patent implements beforehand cushioning by adding a redundant metal layer over the welding seams, which acts as a backup barrier. This additional layer compensates for and cushions against the reliability risks posed by undetected welding defects, ensuring that even if pinholes or imperfections exist in the base metal screen, water tightness is preserved.
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 solution reduces the weight and environmental impact of high voltage power cables while significantly reducing the risk of water intrusion and electrical breakdown by effectively sealing welding defects, enhancing the reliability of long cables.
Implementation Method 1
additive manufacturing techniques to deposit a metal layer at least covering identified welding defects in said welding seam
Implementation Method 2
additive manufacturing techniques, such as cold spray or laser powder deposition
Implementation Method 3
additive manufacturing techniques, such as cold spray or laser powder deposition
Data Source
Figure 1
Figure 2a~2b
Figure 2C~2D
AI summary
The present invention relates to a power cable comprising a cable core (1) comprising at least one conductor (2) with an insulation system (3), and a water barrier system (4) encapsulating said cable core (1) and/or said insulation system (3) of each of the at least one conductor (2), wherein said water barrier system (4) comprises a metal sheath (5) encapsulating the cable core (1) and/or the insulation system (3) of each of the at least one conductor (2), and wherein the metal sheath (5) is made by wrapping a metal foil around the cable core (1) and/or the insulation system (3) of each of the at least one conductor (2) and then welding together opposing ends of the wrapped metal foil forming a longitudinal welding seam (6), characterised in that the water barrier system further comprises an additional metal layer (7) deposited onto an outer surface of the metal sheath (5) and covering at least said longitudinal welding seam (6).