Multisensing Cable Structure for Strain-Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing overhead power transmission line cables face challenges in accurately and reliably measuring strain due to configurations that lead to loss of sensing accuracy and reliability, particularly in compensating for temperature effects on Brillouin frequency shift in strain measurements.
Innovation Solution
A multisensing cable with a distributed fiber optic sensing system, comprising a first optical unit with a tight buffered optical fiber for strain measurement, mechanically congruent with the cable structure, and a second optical unit with loose optical fibers for temperature sensing, both surrounded by conductive or semi-conductive materials to enhance accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a tight buffered optical fiber is fixed to the inner surface of the metal tube for strain sensing, then the mechanical congruence and strain measurement accuracy is improved, but the fiber becomes susceptible to temperature-induced Brillouin frequency shift errors
Solution Approach 1:
The patent divides the sensing function into two separate optical fibers: one tight-buffered fiber for strain measurement and one loose-tube fiber for temperature measurement. This segmentation allows each fiber to be optimized for its specific sensing purpose while compensating for the limitations of the other through data processing.
Solution Approach 2:
The loose-tube optical fiber acts as an intermediary temperature sensor that measures the temperature effect on the tight-buffered fiber. By using this intermediary measurement, the system can compensate for temperature-induced Brillouin frequency shifts in the strain measurement, improving overall reliability.
2Adaptability or versatility
If multiple optical units are integrated into the cable for simultaneous strain and temperature sensing, then the sensing capability is improved, but the device complexity increases
Solution Approach 1:
The patent implements multi-functionality by integrating two optical units into a single cable structure, allowing the same cable to perform both strain sensing and temperature sensing functions simultaneously. This universal design eliminates the need for separate sensing systems.
Solution Approach 2:
The patent uses a nested structure where the first optical unit (tight-buffered fiber) and second optical unit (loose-tube fiber) are both housed within the same cable armor and metal tube structure. This nesting approach consolidates multiple sensing functions into a unified cable design, managing complexity through hierarchical organization.
3Measurement precision
If the optical fiber is mechanically congruent with the cable structure for accurate strain measurement, then the strain sensing accuracy is improved, but induced currents may be generated in the metal tube
Solution Approach 1:
The conductive or semi-conductive layer acts as an intermediary between the metal tube and the optical fiber, providing electrical contact that prevents potential difference buildup and induced currents, while maintaining the mechanical congruence needed for accurate strain sensing.
Solution Approach 2:
The patent changes the electrical parameter of the metal tube by adding a conductive or semi-conductive layer, which modifies the electrical conductivity and prevents induced currents. This parameter change allows the metal tube to maintain its mechanical properties for strain sensing while eliminating the harmful electrical effect.
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 high accuracy and reliability in strain and temperature measurements along the cable length, effectively compensating for temperature influences on Brillouin frequency shift, ensuring precise mechanical congruence and preventing induced currents.
Implementation Method 1
strain may be measured by means of a so-called DSS (Distributed Strain Sensing) system, which is commonly based on Brillouin scattering
Implementation Method 2
temperature can be measured by means of a so-called DTS (Distributed Temperature Sensing) system, which is based, for example, on Raman or Brillouin scattering
Implementation Method 3
the first optical unit is surrounded by at least one layer of a conductive or semi-conductive material electrically contacting the outer surface of the first metal tube
Data Source
AI summary
It is disclosed a cable for an overhead power transmission line, the cable comprising: a first optical unit comprising a first metal tube housing at least one an optical fiber suitable for sensing strain, the at least one optical fiber in the first metal tube being a tight buffered optical fiber fixed to an inner surface of the first metal tube; a second optical unit comprising a second metal tube comprising one or more loose optical fibers suitable for sensing temperature; and an armor comprising one or more layers of metal wires. The first optical unit is surrounded by at least one layer of semi-conductive or conductive material electrically contacting the outer surface of the first metal tube.