Power Performance Measurements for Wind Turbines

What performance does your wind turbine deliver at which wind speeds? Does your wind turbine meet the requirements for certification? Does your wind turbine achieve the power curve warranted by the turbine manufacturer? The power performance measurement of your wind turbine according to internationally recognized standards gives you the necessary answers.  As a specialist for power curve tests, we support you in your measurement – onshore, offshore, worldwide.

Power Curve Measurement

Different types of power performance measurements - from prototype to warranty fulfillment

Whether you are a manufacturer, wind farm operator or investor, we support you with a suitable measurement campaign. A professional determination of the power curve by an independent and renowned measuring institute such as Deutsche WindGuard gives you a reliable answer and thus security for your investment.

Verification of the warranted power curve of your wind turbine


During purchase of your wind farm, you were warranted a certain power curve for your wind turbine by the manufacturer. If the performance of your farm remains below forecasts, the question arises: Is it due to the power curve?  We will find the answer for you.  Depending on the contract, we perform an accredited remeasurement according to the recognized standards IEC 61400-12-1, IEC 61400-12-2, IEC 61400-50-3 (draft), MEASNET or TR2 or a non-accredited measurement outside of standards. In doing so, we master all the output levels of the aforementioned directives. Depending on the site, we adapt the measurement concept to your needs – from conventional met masts to ground-based remote sensing systems to nacelle lidar and nacelle anemometry.


Prototype measurement for certification


As a DAkkS-accredited and IECRE- and MEASNET-recognized test laboratory, we are your partner for prototype measurement as part of turbine and component certification. With our objective, reliable data base, you are ideally equipped – both for certification and for identifying optimization potential. In addition to the power curvetest, we also offer all other prototype measurements required according to IECRE OD-502 and IEC 61400-22, such as load, sound and power quality.


Relative power performance analysis


With a relative analysis of the power performance, also known as side-by-side testing, we can accurately determine changes in the performance of a turbine in relation to other wind turbines in the same farm. The measurement is solely based on SCADA data, without complex additional measurements. This is a useful way to verify effectiveness, especially in the context of aerodynamic optimization measures.


Integral power performance analysis


The integral analysis of power performance is particularly suitable if you want a general idea of the turbine’s actual power performance. This cost-effective method is based solely on the evaluation of energy yield data and provides an initial indication of how the performance of your plant behaves.


Technical elaboration of power curve warranties


When purchasing your wind turbine, we are happy to check the technical clauses of the power curve warranty. This helps you to reduce risks and prevent unpleasant surprises after the conclusion of the contract. As a manufacturer, you can also use our services to formulate attractive offers for your customers at the same time when risks are minimized. Find out more about tender and contract consulting here.


How we measure the power performances of your wind turbine

Power performance measurements on wind turbines basically consists of measuring the wind speed at level while also measuring the output power of the turbine at the same time. These two factors are compared to each other. Depending on the site of your wind turbine or farm, we work with you to create the appropriate measurement concept. We are equipped for the measurement with anemometers and met mast as well as for a measurement with ground- or nacelle-based lidars. We are also accredited for both methods.

Measurement of wind turbine power performance with a met mast

The traditional method of measuring the power performance consists in the installation of a met mast in the vicinity of the wind turbine to be measured. In accordance with IEC 61400-12-1, the met mast is equipped with calibrated anemometers and wind vanes at specified measuring heights. This method is common practice for measurements in complex terrain.

We provide the entire measuring equipment for you and configure the measuring system. All sensors are calibrated by our accredited laboratory.

A major hurdle in power performance measurement is often the procurement and installation of the met mast. We are happy to assist you in selecting a suitable mast manufacturer. In doing so, we draw on an international network of mast manufacturers, with whom we often have long-standing cooperation. With a regional vendor, you can save costs and ensure that local conditions and requirements are met during installation. On request we offer turn-key solutions.

Measurement of power performance with lidar and sodar

According to IEC 61400-12-1, the measurement of power performance by means of lidar is not permitted for all sites. Nevertheless, it can offer a financially attractive alternative to measuring with met masts, especially for offshore wind turbines and in flat terrain. These so-called remote sesning devices measure wind speed by means of light waves. Lidars must be calibrated and classified by an accredited calibration lab.

In special cases, for example in offshore wind farms, nacelle mounted lidars are used. Prior to any campaign, we check whether or not a lidar is suitable for your measurement campaign. Apart from providing you with a plan for your measurement campaign, you can also rent calibrated lidars from us.

State-of-the-art power performance measurements

All our measurements are based on the current state of the art, which we actively help shape. We have actively participated in the committees for all relevant standards on power performance tests, e.g. IEC 61400-12-1 and IEC 61400-12-2 from the very beginning and are still doing so now. Right now, we work on the first international standard for the application of nacelle-lidars in power performance test according to IEC 61400-50-3. The development of the turbulence normalisation procedure  in IEC 61400-12-1, Ed.2 also goes back to our work.

Of course, we ourselves measure according to these standards (with all options) and comply with their requirements. In addition, we also offer you special evaluations far beyond the standard, for example on wind shear and turbulence behavior, site calibration and measurement uncertainties.

How does the measurement work and what do I get?

The measurement is coordinated and planned in advance. In doing so, requirements for measuring equipment as well as precise positioning are defined and a measuring concept is developed that is adapted to the conditions at your site and your needs. Based on this schedule, responsibilities and interfaces are coordinated and the installation is prepared. The installation of the measurement is carried out or monitored by us. During the measurement, data is transferred at least weekly and checked for plausibility. This way, we detect any possible sensor malfunctions early on. All events are documented in a logbook and summarized in a monthly report. After the measurement campaign is completed, you will receive a comprehensive report with all relevant evaluations. This ensures the reproducibility of the measurement.

Why WindGuard is your partner for power performance measurement

WindGuard is one of the most renowned and experienced test labs in the wind industry in the area of power performance measurements. From the active participation in the development of measurement standards to our experience in negotiating power performance warrantees to the support of numerous  R&D projects, WindGuard is always cutting edge.

Precise results through accurate measurements

When it comes to measurements, we leave nothing to chance. We know that in addition to wind speed at hub height and air density, there are many other factors with influence on power performance. By taking into account other meteorological variables (such as turbulence intensity and wind shear) and a detailed uncertainty analysis, we ensure reliable results. Our know-how in the area of wind measurement also benefits us here.

Certified high quality

The high quality of our measurements is regularly assessed and confirmed by independent bodies. We are accredited by the German Accreditation Agency (DAkkS) GmbH as an accredited test and calibration laboratory in accordance with DIN EN ISO /IEC 17025 for the measurement of power performance via met mast and lidar as well as for the calibration of lidars and sodars.

The independent industrial alliances MEASNET and IECRE also accept and certify our competence in power performance measurement.

Recognition by leading manufacturers

Through our work in standardization committees and our long experience in the market, we are recognized by all established turbine manufacturers for power performance measurements. Even measurements on offshore wind turbines, which have not yet been standardized, is accepted when we are in charge. The high quality of our independent measurements is undisputed. For this reason, we are often engaged for the re-measurement of warranted power curves in legal disputes.

Benefit from experience and competence

Our employees are our assets. They are specialists in the installation of measurement systems and the evaluation of data. Our installation teams are familiar with all established turbine platforms and supervise measurements worldwide. They have the usual GWO safety trainings [Link] and are particularly experienced in offshore wind. This way we can offer turn-key solutions for all measurement campaigns.

Our references are impressive: In total, we have performed power performance test on more than 11 GW of wind, 5 GW of this offshore. Rely on experience. Rely on WindGuard.

Information on our accreditations is available here >>>.

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