Une revue du contrôle non-destructif et des besoins de mesure pour l’éolien flottant
5TH March 2015Strictly confidential - All rights reserved
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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
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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
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1. Introduction to floating wind turbines technology readiness and validation
2. Reasons for monitoring floating wind turbines
3. Monitoring methods and case study
Floating wind foundations main technologies
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• 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
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1. Introduction to floating wind turbines technology validation
2. Reasons for monitoring floating wind turbines
3. Monitoring methods and case study
Why monitoring floating wind turbines
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• 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
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• 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
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• 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 up to demonstrator
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• 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)
Monitoring up to demonstrator
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• 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)
Monitoring up to demonstrator
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• 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
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• 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
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1. Introduction to floating wind turbines technology validation
2. Reasons for monitoring floating wind turbines
3. Monitoring methods and case study
Sensors essential to safety
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• 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
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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
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• 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
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• 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
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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
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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
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Goto Islands Spar buoys – force mesaurements
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Goto Islands: Sample of published data
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Monitoring toward physical modelling validation - behaviour
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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