Trefoil Submarine DC Cable Bundling for Axial Slip Stability
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Solution Overview
Problem
The existing methods for installing submarine power cables face challenges in maintaining stability during bundling, particularly in trefoil configurations, leading to mismatched cable lengths and excessive force distribution, which can damage fibre optic cables and cause structural failures in bundling elements.
Innovation Solution
A submarine power cable bundle is formed using a trefoil configuration with a first and second elongated bundling element, where the first element bundles the two bottom DC submarine power cables tightly and the second element bundles these with the top DC submarine power cable more loosely, allowing axial movement to compensate for length mismatches and prevent excessive force accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the submarine cables are arranged in a flat configuration beside each other in one plane, then it is easy to bundle them together, but it is difficult to maintain the cables stable and the centre cable moves out of line risking damaging the fibre optic cable
Solution Approach 1:
The patent applies the trefoil configuration which forms a curved, three-dimensional arrangement of the three power cables around a central fibre optic cable. This curved configuration replaces the flat linear arrangement, providing inherent stability through the geometric interlocking of the cables while maintaining ease of bundling through the systematic trefoil pattern.
Solution Approach 2:
The fibre optic cable is positioned at the centre of the trefoil configuration formed by the three power cables. This nesting arrangement places the delicate fibre optic cable within the protective embrace of the outer power cables, stabilizing it against movement while allowing all cables to be bundled together as a single unit.
2Stability of the object's composition
If the submarine cables are arranged in a trefoil configuration, then the bundle stability is improved, but the inner power cable is compressed and the outer power cable is elongated leading to large compressive and tensile forces
Solution Approach 1:
The patent introduces axial sliding capability between the power cables and the bundling elements, transforming the rigid static trefoil configuration into a dynamic system. This allows the cables to adjust their positions axially during installation, compensating for length mismatches and reducing the accumulation of compressive and tensile forces while maintaining the stabilizing trefoil geometry.
Solution Approach 2:
The patent modifies the bundling parameters by using two different elongated bundling elements with different tightness levels. The first bundling element provides sufficient stability while the second allows controlled loosening, changing the mechanical parameters of the bundle to reduce force accumulation in the cables during installation.
3Shape
If the second elongated bundling element bundles the first bundle and top DC submarine power cable tightly, then the trefoil shape is maintained, but large forces accumulate in the elongated bundling elements leading to failure or excessive compressive force onto the top DC submarine power cable
Solution Approach 1:
The patent applies different bundling tightness levels at different locations within the bundle. The first elongated bundling element bundles the two bottom power cables with appropriate tightness to maintain shape, while the second elongated bundling element that includes the top power cable is deliberately bundled more loosely. This local differentiation in bundling quality allows the trefoil shape to be maintained while preventing excessive force accumulation in the top cable and bundling elements.
Data Source
Figure 1~2
Figure 3~5
AI summary
A submarine power cable bundle (1) comprising: a first bottom direct current, DC, submarine power cable (3a), a second bottom DC submarine power cable (3b), and a top DC submarine power cable (3c), wherein the first bottom DC submarine power cable (3a) and the second bottom DC submarine power cable (3b) are bundled together by means of a first elongated bundling element (7), forming a first bundle (9), wherein the first bundle (9) is bundled together with the top DC submarine power cable (3c) by means of a second elongated bundling element (11), forming a trefoil configuration, wherein the first elongated bundling element bundles (7) the first bundle (9) tighter than the second elongated bundling element (11) bundles the first bundle (9) and the top DC submarine power cable (3c).