EXPORT CABLE OPTIMISATION FOR OFFSHORE WIND FARMSSimon CatmullProject Engineer

12/06/2013

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OUTLINE OF THE APPROACH TAKEN

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THERMALLY CONSTRAINED LOCATIONS

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CABLE OVERVIEW

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Conductor

XLPE Insulation

Polypropylene Filler

Lead Sheath

Armouring

CURRENT DESIGN METHODOLOGY – IEC60287

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Wc Ws Wa

T1

T1

T1

T2T3 T4

3 3 3 ½ Wd½ Wd

Key Assumptions:

1.It’s all concentric circles. 3. Thermal resistances are constant.2.Burial depth is constant. 4. Current is constant at rated power.

Wc=Conductor losses. T1=Thermal resistance between conductor and sheath.Wd=Dielectric losses. T2=Thermal resistance between sheath and armour.Ws=Sheath losses. T3=Thermal resistance between armour and outer serving.Wa=Armour losses. T4=Thermal resistance between outer serving and burial.

EXPERIMENTAL SETUP

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MEASURED DATA

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MODEL VALIDATION – IN AIR

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Initial Model Final Model

Interstices: Discrete polypropylene bundles with air gaps became homogenised volumes.

Semi-Conducting Screens: Thermal resistivity initially identical to XLPE but adjusted to account for heavy carbon doping.

Armour: Armour losses reduced by 40%.

LANDFALL MODELLING

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Soil

Buried Cable

APPLICATION OF RESULTS: SIZING & NUMBER OF CABLES

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Cable Cost

FURTHER WORK: J-TUBES / SANDWAVES

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Bathymetry

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QUESTIONS?

INSTRUMENTATION - THERMOCOUPLES

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INSTRUMENTATION – DISTRIBUTED TEMPERATURE SENSOR

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