Solutions forWind Energy

Services, systems and products

As offi cially acknowledged measuring institution according to § 29b BImSchG for the determination of emissions and immissions caused by noise we are your competent partner in the fi eld of noise control. Thanks to the high level of expertise of our employees you obtain reliable measuring reports, which has also been confi rmed by an independent body by our accreditation according to DIN EN ISO/ IEC 17025.

Measurement of acoustic noise emission

We support you in your position as plant operatorwith the proof of the compliance of your systemwith the sound power levels specifi ed for windfarms which are subject to approval under immis-sion control law.

We support you in your position as plant manufacturer regarding the type certifi cation as well as regarding the identifi cation of those plant components that contribute signifi cantly to the total level and thus have the highest potential for optimization in terms of noise reduction.

Measurement of acoustic noiseimmission

Especially in the commercial and industrial sector we perform measurements of acoustic noise immissions to prove the compliance with the requirements of the authorities. Due to the diffi cult conditions and the fact that at the immission mea-suring points the noise of modern wind turbines can hardly be separated from the background noise, immission measurements are rarely de-manded near wind farms. We can support you in such projects, also when communication and negotiations with the licensing authorities and other parties involved are required.

Acoustics

Noise immission prognosis

In the approval process of wind farms we support you with expert reports for noise immission prog-nosis and help you to provide evidence regarding the compliance with legal requirements. For the calculation of sound propagation we use our IMMI software, which was developed by Wölfel and which is successfully distributed as the leading software for noise and pollutant mapping.

Sound monitoring

For long-term monitoring of your wind farm, we can install and maintain monitoring stations.With a monitoring station you can

collect and analyze system data over a longer period of time,

view measuring data via a powerful Internet platform or

involve the residents in the measuring project via the Internet platform.

Solutions for wind energy2

Sound pressure level in dependence of the wind speed

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Condition monitoring of foundation + tower

Condition monitoring of essential structural compo-nents is becoming increasingly important. Especially in offshore wind farms, due to the limited accessibility, it is necessary to be informed about the current condition and possible changes at any time. Inspections can thus be better coordinated and subsequent damage can be prevented. We provide comprehensive consultation in the planning phase and individually adapted measur-ing systems for the monitoring of foundation and supporting structure. The many years of experience and special expertise of our engineers are of particular value for your project when it comes to data evaluation and assessment. Our customers can use numerous customizable signal analysis modules from Wölfel. In addition to mere structural health monitoring, we also support you with modern statistical methods for the monitoring of wind farms in order to increase the availability of wind turbines and their yield potential.

Electrodynamic shaker systems BD.5 / BD.10

With our electrodynamic shaker systems BD.5 and BD.10 for universal vibration excitation, also the dynamic properties of structures can be analyzed, for example:

natural frequencies mode shapes modal degrees of damping

Measurement of loads and stresses

Vibrations play a decisive role in wind turbines,especially when it comes to questions of fatigue.Since vibrations cannot be entirely prevented, they have to be controlled and minimized.We support you with the extensive experience and expert knowledge of our highly specialized mea-surement engineers. Benefi tting from our com-prehensive measuring instrumentation we are in the position to compose your individual measuring campaign – from the planning phase via the instru-mentation through to the long-term monitoring with summary reports in daily or weekly intervals.

Data acquisition system with more than 200 channels, e. g. for accelerations, acoustic noise, force, strain gauge or further physical quantities (incl. long-term recording)

Comprehensive arsenal of acceleration sensors, microphones, strain gauge technology and diverse wind measuring masts

Experimental Modal Analysis with vibration exciters of all performance classes

Laser vibrometry Recording system for meteorological data Approved technology for data transfer between

rotating (hub, blade) and stationary (nacelle, tower) components

Vibration measurement and monitoring

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1. Spectra of the vibration response2. Waterfall diagram

5 10 15 20 25 30 35

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10−1

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101

Frequenz [Hz]

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frequency

Numerical analysis and simulation

As one of the fi rst engineering companies in Germany, Wölfel started performing computer-oriented analyses for industrial clients in 1971. Due to their many years of experience, our experts can analyze even highly complex structures, for example non-linear systems or the interaction of vibrations and sound radiation.

Analysis of the complete system Load calculation for certifi cation

- Wind and wave loads incl. aero-elastic coupling (BEM) - Full mechanical coupling: Flexural vibrations (blades, tower) and torsional vibrations (power train)

Coupled simulation MBS / FEM for detailed investigations

Analysis of componentsDepending on the problem, we analyze the components using different methods and degrees of detail:

Detailed shell or solid model Simplifi ed beam model Superelement idealization Pure kinematic model

What you get: Analysis and interpretation of loads and

stresses determined Identifi cation of critical spots where damage

can occur Material strength and fatigue analysis Recommendations regarding the optimization

of the structure (e. g. material saving, increase of structural safety)

Vibration analysis

Vibration reduction

As an expert for vibrations and acoustics, Wölfel has vast experience in the fi eld of vibration reduc-tion. In addition to conventional measures like e.g. detuning, our customers can use a wide range of passive and active absorber concepts, which are successfully applied in various industries. In the wind energy sector, we offer solutions for the prevention of tonal acoustic emissions.

Tonality control

Whether passive or active vibration absorbers should be used depends on the requirements. Our product TMD.Sound for passive vibration reduction is particularly effi cient when a sound with a constant frequency, e.g. at rated speed, has to be reduced. With ADD.Sound® we provide a solution to reduce structure-borne and airborne sound in a wide frequency range. Our absorbers are mounted at the gearbox and prevent the transmission of vibrations in the tower and the rotor blades. Tonality surcharges on the sound power level can thus be avoided.

Advantages of TMD.Sound

No energy supply required Low costs due to simple design Can be retrofi tted (troubleshooting)

Advantages of ADD.Sound®

Broadband effect Simultaneous compensation of several tonalities Lower mass small installation space No adjustment required Can be retrofi tted (troubleshooting)

Solutions for wind energy4

Schematic illustration of TMD.Sound

... and during operation

The high loads acting on rotor blades causedamage during operation or lead to damage whichfor the most part originates already during the blade manufacture. Therefore, recurrent inspections during operation are essential to detect possible damage at the rotor blade at the earliest possible and to ensure the quality of the blade.

Services provided by our team of inspectors – onshore and offshore:

Recurrent inspection at the wind turbine External inspections of the rotor blade,

preferably with economical rope access, alternatively by sky-lift (onshore)

Internal inspections including use of crawler camera

Lightning protection measurements Further inspections as required

(e.g. thermography)

Inspection before warranty expiration Generally after 5 years Complete inspection of the blades,

incl. lightning protection system

Repair Supervision Surveillance

Comprehensive documentation Expert report on the rotor blade Expert report on the damage detected Detailed report with photo documentation List of Open Points (LOP)

... during manufacture:Third Party Inspection

Challenge productionThe precise production of rotor blades is essential for the quality of the blades and thus for the service life and energy yield of a wind turbine. Due to the high level of manual labor in the production process, the rotor blades often have defects which can develop into serious damage during operation.

According to estimates by experts approx. 4 out of 5 damage events in the fi eld are related to the production process.

Wölfel as an independent expertAs an independent expert, Wölfel checks the production of the blades on behalf of the operator directly at the manufacturer‘s site and prepares a complete documentation of the deviations in quality.

Our fi eld-tested and proven TPI concept consistsof three complementary elements:

1. General surveillance of the blade manufacture within the scope of process audits;2. Specifi c surveillance of the blade manufacture for concrete customer projects according to our witness point concept;3. Factory Acceptance Test: The project rotor blades are thoroughly tested from the in- and outside, including the lightning protection system and all mounting parts.

Inspection of rotor blades

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Expert inspecting the rotor blade

Visual inspection in the rotor blade

Products

SHM.Blade® / IDD.Blade®

Structural health monitoring of rotor blades with SHM.Blade® and IDD.Blade®

With SHM.Blade® and IDD.Blade®, Wölfel offers a condition monitoring system that can detect struc-tural damage and icing respectively. The aim is to protect the rotor blades, to reduce downtimes and thus to increase the availability and the yield of the wind turbine.

Damage detection with SHM.Blade®

SHM.Blade® detects structural changes relating to a certain reference condition. This referencecondition is determined fully automatically withoutany help from outside and individually for everysingle rotor blade immediately after the activationof SHM.Blade®. During operation, the system continuously calculates condition indicators, which furnish information on the current condition of the blade at all times. By means of a two-level warning and alarm concept the system control is capable to react and prevent subsequent damage.

Ice detection with IDD.Blade®

IDD.Blade® detects ice on rotor blades. As thesensors in the rotor blades directly record the actual icing condition, the results are much more reliable than an assessment based on meteorological parameters. However, the main advantage is that wind turbines which have been shut down due toicing are automatically released for further opera-tion after thawing of the ice.

RoBin

RoBin – Wireless measuring system for the mea surement of acoustic noise emission con-forming to standardsYou want to do measurements of acoustic noiseemission conforming to standards yourself? This ispossible – fast, effi ciently and at reasonable cost –with RoBin, our one-man measurement system, acoherent and complete hard- and software pack-age, offering the following advantages:

No measuring cables: Wireless data transfer Measurement according to the following

standards: - IEC 61400-11 edition 3.0 - IEC 61400-11 edition 2.1 - FGW TR1

Compact: Accessories in handy portable tool boxes

Flexible: Various interfaces for data acquisition Calibratable sound level meter Remote control to tag disturbing noise Effi cient application: Only one person needed

on site

Prevention of serious damage with SHM.Blade®

Online results

Turbine station

Meteo station

Sound station

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Research and development

We are actively involved in research projects in order to be able to offer our customers adequate products and systems that meet also future re-quirements. With such research projects we also help to boost and promote the wind energy sector.

The R+D project “UnderwaterINSPECT“, which we are currently coordinating, is concerned with tech-nologies for the reliable and effi cient inspection of underwater support structures of offshore wind tur-bines. In this project, we are developing a demon-strator for the monitoring of the structural integrity and stability of offshore foundations. A large-scale test regarding this issue will be performed in the test center for support structures of FhG IWES and Hannover University.

In the course of another project, Wölfel also deals with the monitoring of grouted joints.

Our competence

We have the following certifications and accreditations:

Certifi cation according to DIN EN ISO 9001:2008 for the following scope: Consulting, Analysis and Design, Measurement in Strength of Materials, Dynamics, Acoustics for Mechanical, Civil and Plant Engineering

Offi cially acknowledged measuring institution according to § 29 b BImSchG for noise and vibration

Accreditation according to DIN EN ISO/ IEC 17025:2005 in the testing fi elds safety and acoustic for noise, vibrations and building acoustics

Further information

Our projects:

Development support in the fi eld of measure- ments of vibrations and acoustic noise emissions

Measurements of acoustic noise emissions including expert report for the compliance with the permit conditions

Development of solutions for vibration and noise reduction

Third Party Inspection of rotor blades for offshore wind farms

Expertise on damage of rotor blades in case of contingency

Recurrent inspections at rotor blades (e.g. before expiration of warranty)

Selection of referencecustomers:

ABO-Wind Allianz Arise Windpower Bard EnBW Enercon GE Wind Juwi

LuBW Nordex RWE Innogy Senvion Vestas Wind Energy

Institute of Canada WindMW Wotan Group

9 m

14 m

10 m

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Your personal contact

Dr.-Ing. Carsten EbertPhone: +49 931 49708 240Fax: +49 931 49708 650ebert@woelfel.dewww.woelfel.de

www.woelfel.de/wind-energy

© Wölfel Beratende Ingenieure GmbH + Co. KG – 2014 SEP – Subject to changesWEA-14-E-09-2014