Helical High-Voltage Cable Duct Fill Rate
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Solution Overview
Problem
High-voltage electric cables in urban cabling networks tend to heat up and elongate, causing them to snake within cable ducts, leading to suboptimal fill rates and increased bulk, which complicates installation and reduces current-carrying capacity.
Innovation Solution
A helical assembly of three conductors without armouring or sheathing, allowing for greater movement and elongation within the duct, combined with retention elements and stiffening elements to manage thermal expansion and buckling, and a sealing element to prevent water ingress, optimizing the cable duct's fill rate and current-carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cable with armouring and sheath is used, then the cable has mechanical protection and structural stability, but the cable duct fill rate decreases and the cable bulk increases
Solution Approach 1:
The patent removes the armouring and sheath layers from the cable structure, extracting only the essential three conductors. This simplification reduces the cable's external diameter and bulk, enabling a fill rate close to 90% while maintaining the mechanical protection needed through the helical assembly configuration itself
Solution Approach 2:
The cable is segmented into three separate conductors arranged in a helical pattern rather than a single bundled cable with protective layers. This segmentation allows each conductor to move independently during thermal elongation, reducing the overall bulk requirement while maintaining structural integrity
2Quantity of substance
If the cable duct fill rate is increased, then more current-carrying capacity is achieved, but the cable has less space to snake during thermal elongation
Solution Approach 1:
The helical arrangement of the three conductors creates a dynamic structure that can adapt its configuration during thermal elongation. The conductors can separate and follow sinuous trajectories independently, allowing the cable to accommodate thermal expansion even in a tightly filled duct with 90% fill rate
Solution Approach 2:
The patent changes the structural parameters of the cable by eliminating armouring and sheath, and arranging conductors in a helical pattern. This parameter change allows the cable to achieve both high fill rate and adequate thermal elongation accommodation through the inherent flexibility of the helical conductor arrangement
3Volume of moving object
If the ratio between cable outer diameter and duct internal diameter is reduced, then the fill rate increases, but the cable manufacturing complexity increases
Solution Approach 1:
The patent extracts and removes the complex armouring and sheath layers from the cable structure, leaving only the essential three conductors in a helical arrangement. This simplification reduces manufacturing complexity while achieving the desired high fill rate of close to 90%
Solution Approach 2:
Instead of applying uniform protective layers (armouring and sheath) around the entire cable, the patent uses local quality by arranging three conductors in a specific helical pattern that provides necessary protection and structural integrity only where needed, simplifying the overall manufacturing process
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 enables a fill rate of up to 90% in cable ducts, allowing for larger, higher-capacity cables with improved thermal management and reduced manufacturing costs, while maintaining the cable within the duct and preventing water ingress.
Implementation Method 1
A high-voltage cable is made to heat up under the effect of the current which circulates therein. This heating creates an elongation of the cable
Implementation Method 2
The retention element makes it possible to clamp the three conductors in order to block them in the natural longitudinal movement linked to the heating thereof under the effect of the current
Data Source
AI summary
This installation has at least one electric cable (12) having three conductors. At least one cable duct contains at least one section of the cable (12) and at least one connection chamber (10) in which two sections of the cable (12) are connected by means of a connection joint (14). The cable (12) is a helical assembly of the three conductors which comprises neither armouring nor sheath around this assembly.