Aircraft Cable Insulation Reduces Weight and Partial Discharges

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Solution Overview

Problem

Aircraft electrical cables face challenges with high voltage, humidity, temperature, and pressure, leading to partial discharges that degrade insulation and potentially cause electric arcs, while existing solutions do not optimize for reduced bulk and weight while maintaining resistance to partial discharges.

Innovation Solution

An electrical cable design featuring a central conductive element surrounded by a polyimide insulating layer and a fluorinated insulating layer with specific thicknesses, where the total thickness is optimized to minimize bulk and weight, and the fluorinated layer is less than 0.4 mm, ensuring resistance to partial discharges under high voltage and harsh conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If the thickness of the fluorinated insulating layer is reduced to decrease cable weight and bulk, then the cable becomes more compact and lighter, but the resistance to partial discharges deteriorates

Engineering Contradiction:
Improvecable weightVSAvoidresistance to partial discharges
Core Design Contradiction:
Weight of stationary objectVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the insulating materials, specifically using fluorinated polymers with high dielectric strength and optimized cross-linking density. This allows reducing the fluorinated layer thickness while maintaining PD resistance through superior material properties rather than relying solely on thickness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite insulation structure combining polyimide and fluorinated polymer layers. The polyimide provides mechanical strength and thermal stability, while the fluorinated layer provides electrical insulation and PD resistance. This synergistic combination allows thickness optimization while maintaining reliability

Inventive Principle:
Principle #40Composite materials

2Weight of stationary object

If the operating voltage is increased to reduce cable cross-section and mass, then the cable mass is reduced by approximately half, but partial discharges are generated on the insulation surface and within defects

Engineering Contradiction:
Improvecable massVSAvoidpartial discharges
Core Design Contradiction:
Weight of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the electrical parameters of the insulation by using fluorinated polymers with high dielectric strength and optimized cross-linking density. This allows the cable to withstand higher operating voltages (230V or 400V) without generating partial discharges, enabling mass reduction while maintaining safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harmful effect of high voltage into a benefit by using fluorinated polymers that resist partial discharges. The high voltage operation enables mass reduction, while the specialized material prevents the harmful partial discharge effects that would normally occur at such voltages

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Volume of stationary object

If the thickness of the polyimide and fluorinated layers is optimized to minimize cable size, then the cable bulk is reduced, but the resistance to partial discharges under high temperature and pressure conditions deteriorates

Engineering Contradiction:
Improvecable bulkVSAvoidresistance to partial discharges
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The patent optimizes the thermal and chemical parameters of the insulation materials, using fluorinated polymers with high thermal stability and optimized cross-linking density. This allows reducing layer thickness while maintaining PD resistance under high temperature (150°C) and pressure conditions through superior material properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different material properties to different layers: polyimide provides mechanical strength and thermal stability, while fluorinated polymer provides electrical insulation and PD resistance. This localized optimization allows thickness reduction while maintaining reliability under harsh conditions

Inventive Principle:
Principle #3Local quality

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 cable achieves a reduced weight and bulk while maintaining a high threshold voltage for partial discharge inception, preventing degradation and ensuring safe operation at high temperatures and pressures.

Implementation Method 1

a fluorinated electrically insulating layer comprising a fluorinated polymer surrounding said electrically insulating layer comprising polyimide (PI)

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 2

an electrically insulating layer comprising polyimide (PI) surrounding said elongated electrically conductive element

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP3358575B1Electric cable resistant to partial discharges
Publication Date: 2019.11.06 NEXANS SA
  • EP3358575B1 patent drawingFigure 1

AI summary

The present invention relates to an electrical cable comprising an elongated electrically conductive element, an electrically insulating layer comprising polyimide (PI) surrounding said elongated electrically conductive element, and a fluorinated electrically insulating layer comprising a fluorinated polymer surrounding said electrically insulating layer comprising polyimide (PI), said layers having specific thicknesses depending on the cross-section of the elongated electrically conductive element.