Review of Cabling Techniques and Environmental Effects Applicable
Review of Cabling Techniques and Environmental Effects Applicable
Review of Cabling Techniques and Environmental Effects Applicable
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Cable types <strong>and</strong> installation techniques<br />
Power cable diameters can range from 75mm in diameter up to 240mm in<br />
diameter. The larger size being associated with 132kV export cables from<br />
<strong>of</strong>fshore wind farm developments currently under consideration for Round 2<br />
developments.<br />
3.6 Flowlines, Umbilicals <strong>and</strong> Small Diameter Pipelines<br />
Flowlines, umbilicals <strong>and</strong> small diameter pipelines have been included in this<br />
review on the basis that some <strong>of</strong> the burial systems <strong>and</strong> other cable protection<br />
methods are commonly applied to this group <strong>of</strong> subsea products.<br />
These products fall into the larger diameter category (usually at least 200mm<br />
diameter) <strong>and</strong> are typically used to connect remote wellheads to <strong>of</strong>fshore<br />
platforms <strong>and</strong> to provide interconnect facilities between <strong>of</strong>fshore installations.<br />
As well as containing fibre optics <strong>and</strong> power cores, these products have tubing<br />
within the make-up <strong>of</strong> the product which can be used for chemical injection <strong>and</strong><br />
hydraulic power.<br />
The flowlines <strong>and</strong> umbilicals, by the nature <strong>of</strong> their make-up, are constructed<br />
using a specialist manufacturing process, are heavy, have stiff properties <strong>and</strong><br />
also have a large minimum bend radius.<br />
3.7 Background to Safe Installation <strong>and</strong> Protection <strong>of</strong> Subsea<br />
Cables<br />
This section sets out the history <strong>and</strong> background to the need for protection<br />
methods for subsea cables.<br />
3.7.1 THE NEED FOR CABLE PROTECTION<br />
Cable burial <strong>and</strong> other protection measures are used to ensure cables are<br />
adequately protected from all forms <strong>of</strong> hostile seabed intervention. If a cable is<br />
not adequately protected, damage can <strong>and</strong> will occur. Figure 3.5 illustrates the<br />
results <strong>of</strong> seabed deployed fishing gear becoming entangled with an unprotected<br />
cable system. Figure 3.6 shows a typical deployment <strong>of</strong> bottom trawl fishing<br />
gear <strong>and</strong> Figure 3.7 shows how a trawl or otter board can potentially engage <strong>and</strong><br />
snag a subsea cable giving rise to the damage as illustrated in Figure 3.5.<br />
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