Offshore research measurements & focus on structural health monitoring

Offshore Wind Infrastructure

Application Lab (OWI-Lab)

For efficient and reliable offshore wind energy.

Offshore Wind Infrastructure Application Lab

A Flemish Funded R&D initiative that aims to increase the reliability and efficiency of offshore wind farms

OWI-Lab is embedded within Sirris, the collective centre of the Belgian technological industry.

Industrial Initiators of OWI-Lab

Industrial Coordinator Scientific Coordinator

Introduction

What does OWI-lab do?

Investing 5.5M € in test and monitoring infrastructure to support (offshore) wind power R&D in the whole industrial value chain 4 investment programs in R&D infrastructure

Platform to initiate local and European research projects together with industry and universities (SBO, O&O, FP7,…)

Innovation projects with / for companies in the wind power sector

OWI-Lab services

Laboratory testing Field testing (offshore)

Field testing: Offshore measurement campaigns Unique SHM solutions / R&D campaigns

Purpose of the monitoring campaigns: 1) Input for R&D / Optimizations 2) Asset Monitoring (O&M)

Datasets as input for component design

Get better understanding of the behavior how the turbines operate far shore

Monitoring for O&M optimization

Multi-purpose:

Vibrations

Corrosion

Temperatures

…

Dedicated offshore measurements & monitoring system for R&D

Ongoing R&D measurement & monitoring campaigns (MC’s) in partnership with universities

Structural Health Monitoring (VUB)

Corrosion Monitoring (VUB)

Drivetrain Monitoring (KU Leuven)

Drive Train

Dynamic Monitoring

Tower

Dynamic Monitoring

Foundation

Dynamic Monitoring

Corrosion Monitoring

Fatigue Monitoring

Which monitoring?

55 Vestas 3MW V90 turbines

Monopile foundations

46 km Offshore

Water Depths : 16 - 30m

1 Monitored Turbine: C01

72 Vestas 3MW V112 turbines

Monopile foundations

37 km Offshore

Water Depths: 16 – 29m

2 Monitored Turbines:

D06 - H05

Current locations for monitoring

Drive Train

Dynamic Monitoring

Tower

Dynamic Monitoring

Foundation

Dynamic Monitoring

Corrosion Monitoring

Fatigue Monitoring

Validation of SHM package

Ongoing research projects: Vibration-based Structural Health Monitoring (SHM)

What? Monitoring the dynamic behaviour of a structure

Why? lifetime prediction, fatigue calculation, Load monitoring, safety, O&M strategy

Already commonly used in civil engineering & aerospace

Example: Stone cutter bridge Hong Kong

(the most heavily instrumented bridge in the world)

Ongoing research projects: Vibration-based Structural Health Monitoring (SHM)

Ongoing project OWI-Lab conserning SHM in partnership with VUB: CONTINUOUS DYNAMIC MONITORING OF AN OFFSHORE WIND TURBINE

Why?

Excitations of wind and waves have an effect on the offshore wind turbine and are capable of exciting the exciting vibration modes avoid resonant behaviour

Gather insights in dynamic behaviour of wind turbine in offshore conditions input for new designs, optimization of structures

Minimize O&M costs (scour protection around monopile structures)

Identify the current state of the offshore wind turbine (i.e. after a storm the scour protection can be damaged can have an effect on the vibration modes)

Extend lifetime of wind turbine structure

Ongoing research projects: Vibration-based Structural Health Monitoring (SHM)

Why? Example: Identify the current state of the offshore wind turbine

Uncertainty: effect of scour on the dynamics of an offshore wind turbine and its lifetime

Scour = the process where the water current accelerates around the support structure and due to its acceleration picks up and transports soil particles (sand) away from the support structure

Ongoing research projects: Vibration-based Structural Health Monitoring (SHM)

Why? Example: Identify the current state of the offshore wind turbine

Scour affects an offshore wind turbine in 3 ways:

1. Lowering the seabed around the structure reduces the lateral bearing resistance that the foundation pile can mobilize, which may mean that the pile needs to be driven deeper into the seabed

2. Lowering the seabed makes the structure ‘longer’ lowering the natural frequency (can be detected through monitoring) can have implications for fatigue damage

3. A large scour hole will leave the J-tube free-spanning, which eventually may damage the cable if this effect is not taken into account

Ongoing research projects: Vibration-based Structural Health Monitoring (SHM)

Why? Example: Identify the current state of the offshore wind turbine

Current approach: prevent scour by dumping a layer of crushed rocks around the support structure

Costly solution

Scour protection requires inspection and maintenance throughout the lifetime

Ongoing research projects: Vibration-based Structural Health Monitoring (SHM)

How?

Continuously monitor vibration levels and evolution of the frequencies and damping ratios (especially interesting for monopile based turbines ; jacket structure is more stiff than monopile)

State-of-the-art operational modal analysis (OMA) techniques and the use of appropriate vibration monitoring equipment can give insides in natural frequencies, damping ratio’s and mode shapes (cfr. Aerospace)

OWI-Lab continiously monitors one monopile based wind turbine (Vestas V90) at the Belwind wind farm to get insights in the dynamic behaviour of the structure and evaluate new OMA-technique in partnership with VUB (Vrije Universiteit Brussel)

Approach field testing service Structural Health Monitoring )

Advanced post-processing

techniques for

continuous dynamic

monitoring

of the structure

(damping, frequency,…)

Automated Operational Modal Analysis

Measuring Accelerations

Identifying Dynamic

Parameters

Updating FEM-Model

Prediction of Stresses

Life-Time Assesment

Example data set: VIBRATION DATA

Drive Train

Dynamic Monitoring

Combining gearbox surface vibration data with internal flexible multibody models to retrieve information on the relevant parameters for the remaining life assessment of wind turbine gearboxes

High frequency sampled data

Input for MBS-model

CONTINUOUS MONITORING

OF GROUT USING OPTICAL

FIBER TECHNOLOGY

New Measurement

Concepts using optical

fibers

New Innovation Projects (EUROPEAN)

WIFI JIP: Analysing Wave Impacts on fixed turbines

Objective:

To improve the way effects of steep

(and breaking) waves are taken into

account in the design methodology of

fixed offshore wind turbines, so that

optimized offshore wind turbines can

be developed

http://www.owi-lab.be/

@OWI_lab

Group: Offshore Wind

Infrastructure

Application Lab

(OWI-Lab)

Thank you for your attention!

Pieterjan.jordaens@sirris.be