Cable Laminate Water Barrier for Charge Conduction and Sealing
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Solution Overview
Problem
Current water barriers for high-voltage power cables, primarily made of lead, are heavy, have low fatigue resistance, and pose environmental concerns, while also failing to effectively conduct capacitive charges, leading to potential electrical breakdowns.
Innovation Solution
A lightweight, fatigue-resistant water barrier is created by wrapping a laminate structure comprising a metal foil and thermoplastic polymer around the cable core, with strategically uncovered areas on the metal foil to facilitate electrical conductivity and a heat treatment to thermally fuse the layers, ensuring effective water insulation and capacitive charge conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead is used as water barrier material, then reliable water protection is achieved, but weight increases significantly
Solution Approach 1:
The invention uses a composite laminate structure consisting of multiple layers including aluminum foil, adhesive layers, and polyethylene layers. This composite structure replaces solid lead while maintaining water barrier functionality through the combination of different materials, each contributing specific properties (aluminum for water resistance, adhesive for bonding, polyethylene for protection).
Solution Approach 2:
The invention employs thin film structures (aluminum foil and polyethylene layers) to create an effective water barrier. These thin films provide adequate water protection without the bulk and weight of traditional lead barriers, leveraging the barrier properties of thin metallic and polymer films.
2Reliability
If lead is used as water barrier material, then water insulation is provided, but fatigue resistance is insufficient
Solution Approach 1:
The laminate composite structure provides superior fatigue resistance compared to solid lead. The multiple layers bonded together create a more ductile and fatigue-resistant structure that can withstand dynamic loading and thermal cycling without cracking or failing, while maintaining water insulation through the aluminum foil barrier layer.
3Reliability
If lead is used as water barrier material, then water protection is achieved, but environmental harm increases
Solution Approach 1:
The invention replaces toxic lead with environmentally benign materials (aluminum, adhesive, polyethylene) that are non-hazardous to the environment. These materials can be disposed of or recycled without environmental harm, eliminating the pollution issues associated with lead while maintaining adequate water protection functionality.
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
The solution provides a durable, lightweight water barrier that effectively prevents water intrusion and conducts capacitive charges, reducing the risk of electrical breakdowns and addressing environmental concerns associated with lead-based barriers.
Implementation Method 1
the laminate structure is thermally joined by a heat treatment
Implementation Method 2
the metal foil is able to function as an electrically conducive bridge carrying capacitive charges across the water barrier
Data Source
Figure 1a
Figure 1b
Figure 1ci~1civ
AI summary
The present invention relates to a laminate water barrier which is capable of conducting capacitive currents radially out of the cable thus avoiding breakdown due to induced voltage gradients, comprising a laminate structure comprising a metal foil having a lower and an upper surface area, a first layer of a thermoplastic polymer laid onto and covering the lower surface of the layer of metal foil except for a longitudinal uncovered surface area of the layer of metal foil, and a second layer of thermoplastic polymer laid onto and covering the upper surface of the layer of metal foil except for a longitudinal uncovered surface area of the layer of metal foil, and wherein the laminate structure is wrapped around the cable core such that the first uncovered surface area of the metal foil faces the cable core and the second uncovered surface area of the metal foil faces away from the laminate structure, and the laminate structure is thermally joined by a heat treatment.