Credit: Charlie Chesvick
Credit: Charlie Chesvick

Opportunities for Cooperation at Our Research Wind Farm WiValdi

DLR’s WiValdi research wind farm offers a wide range of opportunities for cooperation suitable to your own research and development objectives. Our wind park provides a wide scope of infrastructures for your use, following our aspiration of wanting to supply a research infrastructure appropriate for the whole wind power community. In this regard, it is our goal to cover the industry’s relevant research aspects so that the wind energy sector and all connected systems in Germany and at international level may benefit in the future.

Are you active in the areas of industry and research and interested in cooperation? If so, we will be more than happy to offer you valuable advice as to how we could support you in implementing your projects at our research facilities.

Do you have questions about WiValdi in Krummendeich?

Then get in touch with us.
+49 531 295 3380

Then get in touch with us.
Herr Dr.-Ing. Jakob Klassen

Our utilization units for your research

The WiValdi research wind farm is located at Krummendeich, a municipality in the district of Stade, Lower Saxony, at the mouth of Elbe River. This region is characterized by steady winds, with the West-Southwest being the main wind direction. The land is mainly used for agriculture, with the exceptions of special areas designated to the parking of cranes, measuring masts, and, of course, wind turbines. Several locations within the area can be plugged into a low voltage networkand a data line, thereby making possible the connection of external sensors and other systems. Further projects to be realized at the research facility could include:  

  • the erection of container solutions
  • the use of mobile microphone arrays
  • the use of LiDAR systems.

WTG 1 and WTG 2 are two identical Enercon E-115 EP3 wind turbines, each with a capacity of 4.2 MW, a total height of 150 meters and a rotor diameter of 116 meters. About 1,300 sensors are installed onto each wind turbine generator (WTG) that enable comprehensive knowledge of its overall behavior, especially in relation to the rotor blades. What makes these two WTGs are unique in the world is that they are fully equipped with measurement technology from their foundation piles to their blade tips. The respective instrumentations of both turbines are not identical, which is why WTG 1 and WTG 2 can be used in accordance with the specifics of research interests. Apart from the sensor systems that are integrated during manufacture, e.g., into the foundation pile or into inaccessible locations of the rotor blades, further sensor technology can be added as well, for instance, to validate and calibrate the sensor technology already present in the WTG. Moreover, the access to the control unit makes it possible to operate the plant in line with any project matrix as requested.

A special feature is the spatial array of both multi-MW wind turbines, which are positioned exactly behind each other towards the main wind direction. Although this configuration might seem unfavorable in the view of a commercial operator, it is all the more interesting from a research point of view, since the design allows for experiments on the wake flow. For this purpose, a total of five meteorological measuring masts have been erected, which allow to record the properties of the turbulent wake in great detail. In front of WTG 1, an IEC-compliant measuring mast of 150 meters has been installed downwind, equipped with sensor technology that registers all incoming wind fields with the highest precision. As soon as a wind field hits WTG 1, this will result in a complex turbulence within the wake.

This wake flow is then detected by an array of three measuring masts of 100, 150, and again 100 meters, in front of WTG 2 and oriented towards the main wind direction. In this way, the array makes it possible to measure the turbulent wind field alongside the whole rotor area of WTG 2 before it actually reaches WTG 2. This special configuration enables the exploration of the wake’s effects or to validate existing methods for reducing or deflecting the wake to increase the effectiveness of the entire wind farm.

A fifth IEC-compliant measurement mast is going to be placed upstream of WTG 3.

Investigations on wake flows aside, the measuring masts also enable meteorological research. Sensors for air pressure, humidity, precipitation or the density of cloud covers, along with a LiDAR system, if mounted onto the measuring mast array, will allow for more comprehensive meteorological investigations.

Virtually all sensors employed at the research wind farm are capable of feeding their data into a data management system (DMS). The DMS is installed in the control center and allows the collection of highly synchronous measurement data in different resolutions and time intervals as needed. The time stamps are highly accurate, thereby enabling not only the evaluation of individual data series but also the analysis, combination and validation of a wide variety of sensor systems of different measuring systems and utilization units. The DMS will be capable of compiling data coming from the altogether the 3,500 sensors spread all over the WTGs, measuring masts, and field instrumentation. It will store all data in a fail-safe manner and transfer it to another data management system at DLR’s computer center. Serving as an archive, this DMS will make all data available online for future retrieval and processing.

Possible Research and Development Topics

For ensuring a reliable, affordable and environment-friendly energy supply in the best way possible, an equally environment-friendly, cost-efficient expansion of wind energy is required that is furthermore supported by a large majority of the population. At the WiValdi research wind farm, we are aspiring to contribute to this objective with our research into more efficient, cost-effective, and noise-reduced wind turbines.

Examples for this can be found in selected research topics that represent a selection of possible forms of cooperation with the WiValdi research wind farm (pursuant to the 7th Energy Research Program of the German Federal Ministry for Economic Affairs and Climate Action, Bundesministerium für Wirtschaft und Klimaschutz, BMWK)

Site Development

In Germany, the amount of land usable for any further expansion of wind energy is limited; especially wind-intensive sites on land that have become open to use for the first time are becoming increasingly rare. It therefore is crucial to choose sites of high potential with appropriate procedures and to investigate them over longer periods of time by applying methods that are as efficient as possible. Improved algorithms can help achieve this goal.

Regarding the layout, it should also be considered to what extent the park may exhibit behavior that supports the system. In addition to the three wind turbines, the research wind farm therefore also includes a total of five measuring masts with extensive meteorological sensors intended for evaluating the site. Future smart wind farm layouts will be supported by the turbine control system as well: Here, control algorithms will be employed that intervene with the pitch and yaw angles of the turbines to reduce the wake and thereby increase the performance of the entire wind farm. The WiValdi wind turbines make such intervention into turbine control possible within a safe framework to enable the development and validation of control algorithms.

Component Development

The future evolution of wind turbines hinges on the continuous development of all single components, from foundations to rotor tips. The instrumentation of wind turbines at our research wind farm is, in its scope, unique in the world and therefore offers equally unique opportunities. It is only with a holistic approach that the reliability of the wind park’s entire system can be increased and its costs, therefore, be reduced.

In addition to the incoming sensor data from the two large wind turbines, a third, modular one serves as a test stand for the use of new components. In contrast to the larger turbines, the smaller one allows to replace individual components (such as rotor blades, rotor blade tips, converters, gearboxes or pitch/yaw drives) for testing and validation purposes at much lower costs.

Load Reduction

It is possible to increase reliability and prolongate service life by minimizing the loads acting on wind turbines. Improving the information of incoming winds allows single generators to better respond to changes within wind fields. This is because the wake vortex in the shadow of a wind turbine or wind farm can cause an increasement of loads and a reduction of energy yields.

Therefore, wind farms should be perceived as systems. Consequently, the interactions between individual wind turbines or between wind farms are the subject of ongoing research. The special layout and the extensive instrumentation (both for the detection of incoming and turbulent wind fields in the wake, as well as for the detection of loads hitting the wind turbine) at the reseach wind warm offer unique research opportunities in this context.

Grid Integration

The advancing energy transition and the expansion of renewable energies impose ever more challenges to the existing power grid, both regionally and globally. The previous sole focus on electrical efficiency is being increasingly replaced by a demand for behaviors of wind farm systems that serve existing grids. In this regard, all components of power electronics must be considered, from generators, frequency converters and transformers, to grid feed-in points (and even beyond, if necessary).

Across the grid, issues such as storage, black start capability, grid overload, voltage fluctuations, reactive power compensation, along with many others, need to be understood much better, too.

The possibilities to access virtually all electrical components, as well as its infrastructure, make the research wind farm a unique research environment.

Social Aspects

The acceptance within the population (or lack thereof) is considered one of the greatest challenges for the expansion of wind energy. The WiValdi research wind farm as a real-scale open-air laboratory offers the unique opportunity to study the possible social impacts and effects of a wind farm.

One example are the effects of different operating modes on local residents. The effects of emissions such as noise, shadows, or visual appearance can also be studied with the goal to develop future wind turbines with designs by which residents might feel affected less negatively.

The Rotor

The rotor of a wind turbine determines if and how efficiently wind will be converted into electrical energy. Special attention should thus be paid to this component, especially in respect to processes devoted to the industrialization of turbine production or the noise-reduction of their operation. The latter not only influences the approval of plants, but also their acceptance by local residents.

In this context, the development of cost-effective and reliable technological methods for navigation lights based on public and other requirements,or for an operation mode that spares passing birds or bats is a focus of ongoing research. Especially replaceable blade tips, as planned for WEA 3, provide inisightful opportunities to test new technologies at low costs.

The rotor blades of the wind turbines are equipped with a large number of, partially redundant, sensor systems. The analysis of these sensors spurs a deeper understanding of loads, forces and vibrations acting on the rotor. The choice of materials and structural designs of rotor blades are important factors for creating more efficient and cost-effective wind turbines in the future.

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