Strain Sensor in Heavy-Duty Cable via Intermediary Filler

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Heavy-duty electric cables in mobile installations face challenges in monitoring tensile strain effectively due to external mechanical stresses, which can lead to premature damage and reduced lifespan, and existing solutions do not adequately address the integration of strain sensors within the cables to ensure reliable and long-term measurement.

Innovation Solution

The integration of a strain sensor with mechanical congruence to the cable's longitudinal structural elements, positioned in a neutral region to minimize damage from bending, and a temperature sensor to decouple strain from temperature effects, using Brillouin backscattering techniques for real-time monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an optical fibre strain sensor is embedded or attached to the cable, then real-time strain monitoring is enabled, but the sensor is vulnerable to damage from external mechanical stresses

Engineering Contradiction:

Improvestrain monitoring capabilityVSAvoidsensor durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A strain-transferring filler material is introduced as an intermediary between the optical fibre strain sensor and the cable's longitudinal structural elements. This filler mechanically couples the sensor to the cable structure, transferring strain effectively while protecting the fragile optical fibre from direct exposure to harsh mechanical environments. The filler acts as a buffer that transmits mechanical stress information without subjecting the sensor to damaging forces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical fibre strain sensor is nested within a protective structure consisting of the strain-transferring filler and the cable's longitudinal structural elements. The sensor is positioned centrally within this nested arrangement, allowing it to measure strain through the filler while being shielded from external mechanical damages. This nested configuration enables the sensor to function reliably in harsh environments.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Measurement precision

If the strain sensor is positioned closer to the cable surface for better strain transfer, then measurement accuracy improves, but the sensor becomes more susceptible to bending damage

Engineering Contradiction:

Improvestrain transfer efficiencyVSAvoidbending damage risk

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The strain-transferring filler serves as a mediator that decouples the sensor position from the requirement for direct surface contact. It transmits strain effectively over distance, allowing the sensor to be positioned in a protected location while maintaining accurate strain measurement. The filler's mechanical properties enable effective strain transfer without requiring the sensor to be exposed to damaging environments.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple redundant fibres are used to protect against sensor damage, then reliability improves, but system complexity and cost increase

Engineering Contradiction:

Improvesensor protectionVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Rather than using multiple redundant fibres, a single optical fibre strain sensor protected by the strain-transferring filler is employed. The filler provides mechanical protection and strain transfer functionality, eliminating the need for redundant sensor elements. This approach maintains reliability while reducing system complexity and cost.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution allows for reliable real-time monitoring of tensile strain and temperature within the cable, preventing premature damage and enabling timely maintenance, thus extending the cable's lifespan and reducing unexpected outages and costs.

Implementation Method 1

Methodology Applied

Scientific EffectBrillouin backscattering: Brillouin Scattering

Implementation Method 2

using Brillouin backscattering techniques for real-time monitoring

Methodology Applied

Scientific EffectBrillouin scattering: Brillouin Scattering

Data Source

PatentEP2555205B1Monitoring system for detecting strain in at least one electric cable

Publication Date: 2019.12.04 PRYSMIAN SPA

Figure 1a
Figure 1b~2b
Figure 3

AI summary

An electric cable comprising a strain sensor longitudinally extending along the cable and including a strain optical fibre arranged within a bending neutral region surrounding and including a bending neutral longitudinal axis of the electric cable, and at least two longitudinal structural elements, at least one of the at least two longitudinal structural elements being a core comprising an electrical conductor, wherein the strain sensor is embedded in a strain-transferring filler mechanically coupling at least one of the at least two longitudinal structural elements with the strain sensor. With the disclosed cable construction, the strain experienced by the at least one of the at least two longitudinal structural elements is transferred to the strain sensor at least in a strained condition. In the preferred embodiments, the electric cable is a heavy-duty cable. The invention relates also to a method for monitoring the strain, and preferably also the temperature, of an electric cable. Further, the invention is directed to a deformation monitoring system for measuring at least the tensile strain of a plurality of electric cables, and in particular of a plurality of heavy-duty cables.