Power to the People.
Protecting Wind Farm Cable Infrastructure
Last October, the government launched its plan to increase its offshore wind power capacity from 30GW to 40GW by 2030; part of its commitment to meeting net‑zero carbon by 2050. While experts disagree on whether this increase in capacity will be met in time, significant investment must take place across the country’s offshore windfarm infrastructure to help meet these targets.
Installing and maintaining the wind turbines is not without its challenges. Protecting the huge runs of electric cables requires careful consideration in the harsh, marine environment.
Alex Smith, Technical Director from flexible conduit manufacturer, Flexicon addresses the key areas to be considered when protecting electrical cables from the elements and securing unmanned installations.
Metallic or non‑metallic?
One of the first decisions is whether to specify metallic or non-metallic flexible conduit. Both material types can be suitable for the environment, and it is often the case that specification is based on preference, rather than considering the full range of hazards that the cabling may be exposed to.
For example, 316L, marine-grade stainless steel options can offer high ingress protection, corrosion resistance and mechanical strength in the harsh marine environment, with inherent UV resistance.
Nylon conduits can provide excellent UV resistance where cabling is exposed to the elements. Heavyweight, non-metallic flexible conduit can also offer suitability in low temperatures, and offers the benefit of returning to shape in the event of impact.
Let’s consider some of the other factors which can affect material selection.
Protection from salt spray
The corrosive effects of salt water can have a detrimental effect on cable protection systems, potentially exposing cabling and impacting on operational performance and uptime.
One means of assessing suitability for the demands of the marine environment is to conduct salt spray testing to check the product and surface coating performance.
Flexicon, for example, subjects its products to 1000 hours of standardised salt spray testing. Despite this corrosive test, Flexicon’s SSU, FSS, LTPSS and FPRSS conduits, which are all manufactured using marine grade 316L stainless steel, endure only minimal corrosion and are not compromised.
Managing long cable runs Strain relief fittings can be placed in long cable runs, especially for delicate fibre optic or data cables, to help secure and protect. When run over an extended drop, cables can suffer from elongation and break. Using strain relief fittings, or glanding off at bulk heads, can help to alleviate this issue and support the cabling from the risk of movement.
Metallic braided systems Control cabling may be running alongside high voltage cables, which can cause electromagnetic (EMI) interference. Over-braided flexible conduit systems can be used to provide excellent screening properties, and to prevent any spurious data being transferred via the controls or communications’ system.
This is of prime importance as the wind turbine will be monitored remotely. Engineers need to have confidence that the data is accurate as a faulty reading could result in a maintenance crew being sent to site unnecessarily.
Cost, time, and safety are of prime concern, and just one broken wire could take a complete windfarm offline. Ensuring cable protection is specified accurately, based on the hazards it will be exposed to, will pay dividends, helping to reduce cost of ownership by protecting uptime.
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