Submarine Power Cable Sections With Localized Water Permeability Control

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Solution Overview

Problem

Submarine power cables face challenges in effectively protecting the insulation system from radial water ingress, particularly in sections where traditional lead-free metallic barriers may not provide sufficient protection, leading to potential moisture-related issues and increased material and weight requirements.

Innovation Solution

A submarine power cable design featuring a mechanically flexible sheath with lower radial water permeability in specific sections, combined with a polymeric sheath and optional metallic water blocking layers, to enhance protection and reduce material usage by allowing simpler barrier solutions in other sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lead sheath is used as a radial water barrier, then protection against radial water ingress is improved, but weight and material usage increase

Engineering Contradiction:
Improveprotection against radial water ingressVSAvoidweight of cable
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent applies different water barrier solutions to different sections of the cable based on local requirements. The first section has a mechanically flexible sheath with lower radial water permeability, while second sections have a polymeric sheath with standard water permeability. This local differentiation allows weight reduction in sections where full protection is not critical, while maintaining adequate protection where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite material structures combining polymeric sheath with water blocking layers. The water blocking layer is arranged between the polymeric sheath and the insulation system, creating a composite barrier that provides effective water protection with reduced weight compared to traditional lead sheaths.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a mechanically flexible sheath with lower radial water permeability is applied along the entire cable, then protection against radial water ingress is improved, but material usage and weight increase

Engineering Contradiction:
Improveprotection against radial water ingressVSAvoidmaterial usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements local quality by providing enhanced water protection (mechanically flexible sheath with lower radial water permeability) only in the first section where moisture-sensitive regions are located, while using standard polymeric sheath in second sections where protection requirements are lower. This selective application optimizes material usage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cable is segmented into different sections with different protection levels. The first section (with joints or moisture-sensitive regions) receives enhanced protection, while second sections (with lower requirements) use standard protection. This segmentation allows material optimization based on actual needs of each section.

Inventive Principle:
Principle #1Segmentation

3Quantity of substance

If simpler barrier solutions are used in sections with lower requirements, then material usage is reduced, but protection against radial water ingress may be insufficient

Engineering Contradiction:
Improvematerial usageVSAvoidprotection against radial water ingress
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent matches the level of water protection to the local requirements of each section. Second sections with lower requirements use simpler polymeric sheath barriers, while the first section with moisture-sensitive regions uses the more protective mechanically flexible sheath. This ensures adequate protection is provided where needed without over-protection where not required.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the water permeability parameter of the sheath based on section requirements. The mechanically flexible sheath in the first section has lower radial water permeability, while the polymeric sheath in second sections has higher (standard) permeability. This parameter differentiation optimizes both protection and material usage.

Inventive Principle:
Principle #35Parameter changes

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 design effectively protects moisture-sensitive regions within the cable, potentially reducing material usage and weight while ensuring adequate radial water ingress protection, even in sections with lower requirements, by strategically applying water-blocking layers and tapes.

Implementation Method 1

a water blocking layer arranged around the insulation system along at least 20% of the length of the first section

Methodology Applied
Scientific EffectPhysical barrier:

Implementation Method 2

the mechanically flexible sheath has a lower radial water permeability than a radial water permeability of any layer arranged outside the insulation system in the second sections

Methodology Applied
Scientific EffectPermeability control:

Data Source

PatentEP4432311A1Submarine power cable having sections with different water permeability
Publication Date: 2024.09.18 NKT HV CABLES AB
  • EP4432311A1 patent drawingFigure 1~2
  • EP4432311A1 patent drawingFigure 3~4
  • EP4432311A1 patent drawing

AI summary

A submarine power cable (1) comprising a conductor, an insulation system arranged around the conductor, the insulation system comprising an inner semiconducting layer, an insulation layer arranged around the inner semiconducting layer, and an outer semiconducting layer arranged around the insulation layer, and a polymeric sheath arranged around the insulation system, wherein the first section (1c) has a mechanically flexible sheath arranged around the insulation system, wherein the mechanically flexible sheath has a lower radial water permeability than a radial water permeability of any layer arranged outside the insulation system in the second sections (1a, 1b).