Trefoil Submarine Power Cable Bundling for Stable Cable Laying
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Solution Overview
Problem
The installation of submarine power cables in a flat configuration is challenging due to instability, which can damage the fibre optic cable and cause mismatched lengths leading to excessive compressive and tensile forces in the cables, especially when bending over a vessel chute.
Innovation Solution
A trefoil configuration is adopted using two bottom DC submarine power cables bundled together by a first elongated bundling element and the top DC submarine power cable by a second elongated bundling element, allowing the top cable to slide axially while maintaining stability and preventing flattening, with specific tensioning and lay lengths to manage forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cables are arranged in a flat configuration, then installation is simpler, but the bundle becomes unstable and risks damaging the fibre optic cable
Solution Approach 1:
The patent applies a trefoil configuration that creates a curved, non-planar arrangement of cables around a central axis. This curved geometry provides inherent stability to the bundle during installation, preventing the cables from shifting out of position while maintaining relative simplicity in the bundling process. The circular cross-section of the trefoil configuration distributes forces evenly, enhancing bundle stability compared to flat arrangements.
2Stability of the object's composition
If cables are arranged in a trefoil configuration, then bundle stability is improved, but large compressive and tensile forces accumulate in the individual cables
Solution Approach 1:
The patent modifies the bundling parameters by using two distinct elongated bundling elements with different tightness levels. The first bundling element applies tighter constraints to maintain stable trefoil configuration, while the second bundling element applies looser constraints to allow controlled sliding motion. This parameter differentiation enables the system to maintain stability while reducing excessive force accumulation in the cables during installation.
3Stability of the object's composition
If the second elongated bundling element holds the bundle tight, then bundle stability is maintained, but the top cable cannot slide axially to compensate for length mismatch
Solution Approach 1:
The patent applies different local qualities to different parts of the bundling system. The first elongated bundling element provides tight local constraints to maintain trefoil configuration stability, while the second elongated bundling element provides loose local constraints that permit axial sliding. This spatial differentiation of bundling tightness allows the system to simultaneously maintain overall stability while enabling necessary adaptive motion at specific locations.
4Shape
If the first elongated bundling element bundles the bottom cables very tight, then the trefoil shape is maintained, but the top cable may be squeezed and the configuration may flatten
Solution Approach 1:
The patent implements a cushioning mechanism by using the second elongated bundling element with looser constraints to prevent excessive compression of the top cable. This secondary bundling element acts as a protective layer that allows controlled movement and prevents the top cable from being squeezed between the bottom cables, thereby cushioning against potential damage and maintaining the trefoil configuration without flattening.
Data Source
AI summary
A submarine power cable bundle including: a first bottom direct current, DC, submarine power cable, a second bottom DC submarine power cable, and a top DC submarine power cable, wherein the first bottom DC submarine power cable and the second bottom DC submarine power cable are bundled together by means of a first elongated bundling element, forming a first bundle, wherein the first bundle is bundled together with the top DC submarine power cable by means of a second elongated bundling element, forming a trefoil configuration, wherein the first elongated bundling element bundles the first bundle tighter than the second elongated bundling element bundles the first bundle and the top DC submarine power cable.