Une revue du contrôle non- destructif et des besoins...

Une revue du contrôle non-destructif et des besoins de mesure pour l’éolien flottant

5TH March 2015Strictly confidential - All rights reserved

Strictly confidential - All rights reserved 2

1. Introduction to floating wind turbines technology readiness and validation

2. Reasons for monitoring floating wind turbines

3. Monitoring methods and case study

Ideol: what we do


We do floating wind foundations

Probably the first team to seriously consider barges as an option for floating foundations

The hull is made of concrete or steel

Mixed materials for mooring lines (chain, steel/synthetic cables)

Fatigue performance drives a few components


1. Introduction to floating wind turbines technology readiness and validation



Floating wind foundations main technologies


• Floating wind turbines are in the process of being validated: several demonstrators are at sea.

• Floating wind turbines are still not ready for series production and deployment

Floating wind foundations main technologies



1. Introduction to floating wind turbines technology validation



Why monitoring floating wind turbines


• Reasons for monitoring depend on the technology readiness levels:• The priority is given to the global

behaviour at lower readiness levels• The emphasis of pilot wind farm

monitoring is placed on turbines interactions, scaling cost-saving estimates, operating procedures and ageing estimates

• During commercial phase, the monitoring will mainly aim at ensuring the safe and effective operation of the wind farm

Why monitoring floating wind turbines


• At all levels, there will need to be data related to (by order of precedence):• Safety and environment protection• Production• Wear• Physical models validation

Monitoring up to demonstrator


• Monitoring toward safe performance:• Control of platform position (is it drifting,

still upside up ?)• Control of water ingress / structural

integrity• Navigational safety• Control of wind turbine safety as on land• Safety of personnel transfer• Personnel occupational safety during

maintenance



• Monitoring toward Environmental protection:• Control of materials during construction• Monitoring of potential damage to the

environment due to export cable• Quantification of mooring lines damage• Potential scoring at anchors location• Verification of the efficiency of noxious

substances spill control measures• Impact to marine life (positive or

negative)



• Collecting data toward models and production validation:• Production Vs environmental conditions• Verification of start-up, shut-down,

standby• Validation of power curve• Derivation of loads and stresses• Validation of motions Vs environment,

operation modes• Verifications based on single

units

Monitoring at later stages


• All issues are very similar to the single unit demonstration, however:• Safety monitoring will be limited to the

detection of potential incidents• Only a limited number of units will be

fitted with the full set of sensors• There will be data collected toward the

evaluation of wind turbines interaction• Physical models validation will be

limitted to


1. Introduction to floating wind turbines technology validation



Sensors essential to safety


• Wind turbine status and operation (regular wind turbine SCADA)

• Wave and wind conditions: anemometer and wave buoy

• Floater position (low frequency): DGPS + compass (magnetic or gyro)

• Floater position (wave / wind frequency): accelerometers

• Water ingress detection: capacitive sensors• Bilge water pumping (when fitted) : status of

equipment• Navigation systems status: lights status• Emergency source of supply: remote start-up and

shut-down, status, safeties

Occupational Personnel safety


Crew transfer Staff sea-sickness

Test of several crew

boats and verification of relative motions

Documention of crew transfer

operations for future operators

Recording of accelerations

and verification against sea-

sickness criteria

Environmental impact


• Most data exist from the oil and gas industry, but it is proprietary and cannot be accessed

• Main means to record potential damage: compare status before, during and after ops

• Combination of physical survey (bathymetry, surface sediment layers, water temperature)

• And life surveys (bird watching, plankton, etc.)

Monitoring toward physical modelling validation – wear / durability


• We collect data toward models validation, estimate of the wear of components,

• Only very basic NDT techniques are used at sea today• Due to limited time available for inspections and• Potential for development of techniques is consequently

high• More insight in materials behaviour toward qualifying their

durability would be of interest

Goto Islands Spar buoys – behaviour assessment


On Goto Island, the University of Kyoto installed:– A half-scale spar

buoy,– A full scale 2MW

spar buoy,– Design life = 2

years for both units,

– Hitachi downwind turbines

Goto Islands Spar buoys – behaviour assessment


On Goto Island, the University of Kyoto installed:– A half-scale spar buoy,– A full scale 2MW spar buoy.– Design life = 2 years for both units

All the monitoring system is designed to remain low cost, using the limited life spanLimitted number of

Goto Islands Spar buoys – Sensors


Goto Islands Spar buoys – force mesaurements


Goto Islands: Sample of published data


Monitoring toward physical modelling validation - behaviour


The main objectives for floating wind turbines are the confirmation of:– Platform motions– Wind turbine production– Global loads in hull– Stresses at hot spots– Mooring lines loads

Une revue du contrôle non- destructif et des besoins...

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