Lead-Free Subsea Cable Water Barrier With Helical Reinforcement
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Solution Overview
Problem
Existing subsea power cables face challenges in providing durable water protection without using lead-based sheaths, as alternatives like corrugated copper or aluminum alloys suffer from poor ductility and mechanical durability, leading to potential cracks and insufficient water barrier integrity.
Innovation Solution
A water barrier comprising a first layer of a lead-free metal sheath, reinforced by a second layer of a wrapped reinforcing layer made of carbon fiber, reinforced polymer composite, or metal, such as stainless-steel, which is helically wrapped around the first layer to enhance mechanical durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-free metal sheaths (copper or aluminum alloys) are used to replace lead-based sheaths, then environmental concerns are addressed, but mechanical durability and water barrier integrity deteriorate due to poor ductility and cracking in buckling portions
Solution Approach 1:
The invention uses a composite structure consisting of an inner lead-free metal sheath (copper or aluminum alloy) combined with an outer polymeric water barrier layer. This composite design compensates for the poor ductility and cracking susceptibility of lead-free metals by providing a flexible polymeric outer layer that maintains water barrier integrity while allowing the metal sheath to fulfill its electrical and structural functions without lead.
2Object-affected harmful factors
If lead-free metal sheaths are used to replace lead-based sheaths, then environmental concerns are addressed, but mechanical durability deteriorates due to cracks in buckling portions
Solution Approach 1:
The composite structure combines the electrical conductivity and structural framework of lead-free metal sheaths with the mechanical flexibility and crack resistance of polymeric materials. The polymeric water barrier layer acts as a protective outer shell that prevents crack propagation and maintains mechanical durability under bending and buckling conditions.
Solution Approach 2:
The polymeric water barrier layer functions as a flexible protective shell that can accommodate bending and buckling deformations without cracking. This flexible layer surrounds the rigid metal sheath, providing mechanical durability while maintaining the water barrier function that rigid metal sheaths alone cannot achieve under dynamic conditions.
3Reliability
If lead-based sheaths are used, then excellent water barrier properties and mechanical endurance are achieved, but environmental concerns arise
Solution Approach 1:
The invention extracts and eliminates the harmful lead component from the sheath structure while preserving the essential water barrier and mechanical protection functions through alternative materials. The lead-free metal sheath combined with polymeric water barrier layer replaces the lead-based sheath, removing the environmental hazard while maintaining functional performance.
4Object-affected harmful factors
If lead-free metal sheaths are used, then environmental concerns are addressed, but mechanical durability deteriorates due to poor ductility
Solution Approach 1:
The composite structure combines the electrical and structural advantages of lead-free metal sheaths with the superior ductility and flexibility of polymeric materials. The polymeric water barrier layer provides the ductility and ease of operation during cable installation and handling that lead-free metals lack, while the metal sheath maintains its electrical conductivity and structural integrity.
Data Source
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AI summary
The present invention relates to electrical power cables (1). More specifically, the present invention relates to a water barrier for surrounding a cable core of an electrical power cable (1), wherein the water barrier comprises a first layer of a lead-free metal sheath (4), and a second layer (5) for reinforcing the lead-free metal sheath (4), wherein the second layer surrounds the first layer. Further, the present invention relates to power cables (1) comprising an electrical conductor (2) and the water barrier according to the invention, wherein the water barrier surrounds the electrical conductor (2).