Multi-Layer Power Cable Water Barrier With Offset Seams

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Solution Overview

Problem

Conventional power cables face challenges with moisture penetration due to the heaviness and toxicity of lead moisture shields, and the risk of water intrusion through weak points in metal laminate or welded seams in existing moisture barrier solutions.

Innovation Solution

A power cable design featuring multiple concentric metallic water blocking layers, including a semiconducting polymer layer, with overlapping edges bonded by adhesive or solder to reduce heat damage and diameter reduction, and offset seams to minimize water intrusion risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lead moisture shield is used to provide a safe barrier against water penetration, then water resistance is improved, but the cable becomes very heavy and lead toxicity creates environmental hazards

Engineering Contradiction:
Improvewater resistanceVSAvoidcable weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The single lead moisture shield is segmented into multiple separate metallic water blocking layers (first and second layers) with a semiconducting polymer layer between them. This segmentation allows each layer to be thinner while collectively providing equivalent or superior water resistance, significantly reducing the overall weight of the cable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite materials by combining different metallic layers (aluminum or copper foils) with a semiconducting polymer layer, replacing the single lead material. This composite structure provides effective water barrier properties while being lighter and environmentally friendly.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple metallic water blocking layers are provided with offset seams, then water resistance is enhanced, but the device complexity increases

Engineering Contradiction:
Improvewater resistanceVSAvoidcable structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The multiple metallic water blocking layers are nested concentrically around the insulation system, with each layer positioned at a different radial distance. This nested configuration integrates multiple protective functions into a compact cylindrical structure, minimizing the increase in overall cable dimensions while providing enhanced water resistance through offset seam positioning.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enhanced water resistance and reduced risk of moisture ingress, with the option for multiple layers to ensure protection even if one layer fails, and the use of lead-free materials addressing toxicity concerns.

Implementation Method 1

bonded by adhesive or solder

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

bonded by adhesive or solder

Methodology Applied
Scientific EffectSoldering: Soldering

Implementation Method 3

a semiconducting polymer layer arranged concentrically with and around the first metallic water blocking layer

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP4231317A1Power cable with multiple water barriers
Publication Date: 2023.08.23 NKT HV CABLES AB

AI summary

A power cable (1) comprising: a power core (3a) including: a conductor (5), an insulation system comprising an inner semiconducting layer (9) arranged around the conductor (5), an insulation layer (11) arranged around the inner semiconducting layer (9), and an outer semiconducting layer (13) arranged around the insulation layer (11), a first metallic water blocking layer (15) arranged concentrically with and around the outer semiconducting layer (13), a semiconducting polymer layer (19) arranged concentrically with and around the first metallic water blocking layer (15), and a second metallic water blocking layer (21) arranged concentrically with and around the semiconducting polymer layer (19); and an outer sheath (25) arranged around the second metallic water blocking layer (21).