owi monitoring-reduced

Christof Devriendt www.bruwind.eu

The Offshore Wind Infrastructure Project


The Offshore Wind Infrastructure ProjectObjectives

1. Create testing and monitoring infrastructure for offshore wind energy

• Accelerated lifetime component testing• Structural health and Performance Monitoring• Wind measurements

2. Generate datasets3. Develop advanced data interpretation and

modeling techniques4. Implement enhanced O&M strategies


The Offshore Wind Infrastructure ProjectLidar

Fix/FloatingClimate

ChamberMonitoringSystems

Acquiring Knowledge of wind climate in wind

farm, wakes, performance

Acquiring Knowledge of component lifetime

Acquiring Knowledge on Structural Health and

Performance Monitoring

O&M


Failures Offshore Wind Turbines

Bearing, Shaft– Wear, pitting– Deformation– Fatigue

Tower and Foundation– Resonance– Fatigue– Corrosion– Cracks

Rotor Blades– Surface roughness– Icing– Fatigue, cracks– Loosening at the blade roots

Gearbox CMS Data– Offset, misalignment– Unbalance– Tooth wear

Generator– Electrical asymmetries– Overheating

Pitch and Yaw System– Angle offset– Hydraulic failures– Motor failure

Power Module– Failure Frequency convertor– Failure Switching Gear– Failure Transformer


Monitoring Offshore Wind Turbines Gearbox CMS Data

Vibration data Acoustic Emission data Oil quality & temperatureGenerator CMS Data Vibration data Phase currents Temperatures windingsBearings CMS Data Vibration data Temperature

Meteorological Data Wind Speed Wind Direction Air Temperature/Pressure Rain

Transformer Diagnosis Data Discharge measurements Velocity measurements switches Oil Analysis Temperatures

Performance Data Power Rotor Speed

Pitch Yaw Process Data Currents measurements Angles Temperatures

Blade & Tower SHM Data Vibration data Strain measurements Acoustic Emission data Blade root moments

SHM – O&M platform– Data Analysis– Damage: location, size, type– O&M Decision making software


Load MonitoringChallenges

1. How can load quantities e.g. blade root loads, rotor loads, tower loads be measured and processed in a practical way.

2. Site wind conditions might not satisfy those used in the design of wind turbines IEC61400-1, what are the real wind and wave loads

3. Can inverse methods be applied for identifying the real wind loads

4. Can load monitoring be used for structural health monitoring

Proposed solutions using the standards and recently developed techniques by VUB

5. Direct measurements of mechanical load according IEC 61400-13 standards

6. Direct measurement of real wind loads and wave heights

7. Identifying time-varying wind loads on structures from in situ vibration response data using inverse methods

8. Applying real loads in Finite element and analyze measured and modeled loads


Dynamic MonitoringChallenges1. How can the dynamic behaviour of a wind turbine be analyzed

during operating conditions

2. Existing operational modal analysis techniques are strictly speaking not applicable due to harmonic content of the aerodynamic loads

3. The dynamic behavior of wind turbines is characterized by high aerodynamic damping and nearby modes

4. How to deal with wind turbulences when pitch excitation is used for dynamic testing of operating wind turbines

Proposed solutions developed by the VUB/AVRG and to be validated on wind turbines

5. Operational Modal analysis using transmissibility measurements. This is a recently developed OMA techniques that makes no assumption about the nature of the loads

6. The Polyreference Least Squares Frequency domain OMA approach well known for its clear stabilsation diagrams also for highly damped structures and nearby modes

7. OMAX approach combines experimental modal analysis with operational modal analysis by considering both the excitation signal and the turbulence excitation as valuable data

Figure from Applicability Limits of Operational Modal Analysis to Operational WindTurbinesD. Tcherniak+, S. Chauhan+, M.H. Hansen

Figure from Full-scal modal wind turbine tests: comparing shaker excitation with wind excitation; In Proceedings of IMAC 28


Corrosion Monitoring Challenges

1. Can corrosion be predicted for a complex structure like offshore wind turbines located in a harsh environment ?

2. How accurate are these predictions and can the accuracy be improved ?

3. How can the corrosion performance in the splash zone be optimized ?

4. What is the potential for continuously monitoring the state of the CP system / the state of the monopile ?

5. What alternative factors may cause unexpected corrosion.

Proposed solutions developed by VUB

6. Lifetime prediction based on a Potential Model, including CP performance.

7. Expanding the capabilities of the model by measuring relevant parameters at the turbine location (O2, salinity, T, pH) + lab-scale experiments using these parameters to generate model input.

8. Screening of potential proven coating alternatives

9. Implementing the SURF corrosion sensor on a test location

10. Focus on biofilms / microbial effects, interior of the pile…


Performance Monitoring Challenges

1. Can power curves* obtained from SCADA data be used for fault prediction and diagnosis in wind turbines

2. What is the most adequate approach to estimate and model the power curves of wind turbines

3. Can the detected outliers be correlated with a specific fault

Proposed solutions to be investigated

4. Non-parametric modeling based on e.g. data mining approaches

5. Parametric modeling using e.g. Least Squares estimation techniques

6. On-line monitoring by e.g. residual approach, control charts, trend analysis

7. Labeling SCADA data with status/fault codes

Figures from On-line monitoring of power curves; Andrew Kusiak*, Haiyang Zheng, Zhe Song; Renewable Energy 34 (2009) 1487–1493 *Measurement Power Curve according IEC 61400-12


Research Questions, Needs and Solutions STRUCTURAL HEALTH MONITORING FOUNDATION, SUPPORT STRUCTURE, TOWER and

BLADES

- What are the real loads acting on these structures and how can they be measured- How can the dynamic behavior foundation and support structure be monitored and its design be improved- How accurate is prediction about the dynamic behavior of the foundation, tower and blades- How can the dynamic behavior wind turbine, tower and blades be monitored during operation- Can structural health monitoring be achieved from the measured load data and the identified dynamic behavior- How can a robust corrosion monitoring technique for offshore wind turbines be implemented

Solutions

- Load Monitoring using direct and inverse methods - Dynamic monitoring of tower and support structure using operational modal analysis- Corrosion monitoring of support structure using modeling and sensors- Finite Element Modeling for structural design, load estimation and monitoring

-PERFORMANCE MONITORING- Can performance monitoring and fault prediction be obtained from SCADA data

Solutions- Power Curve Monitoring using parametric and non-parametric approaches - Trend analysis and data mining Finally how can performance monitoring, structural health monitoring and wind data be combined in one improved O&M tool

Christof Devriendt www.bruwind.eu 11

Contact:Dr. ir. Christof Devriendt

Vrije Universiteit Brussel | Pleinlaan 2 | B-1050 Brussel | Belgium

Dept. of Mechanical Engineering | Acoustics & Vibration Research Group

Tel. +32 2 6292390 | Fax +32 2 6292865 | GSM +32 477412049

Mail: [email protected]

www.bruwind.eu

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