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Experimental verification of design loads of small wind turbines for stand- alone power generation


- to compare the design loads of small standalone wind turbines, calculated by the draft IEC standard for small wind turbines, ref.[1], with load measurements carried out on different types of machines installed on different site types,
- to contribute to the development of standards and uniform test methods for small standalone wind turbines in the EC.

The long term objective is to promote the utilization of small wind turbines as an ecologically benign technology for power generation in remote areas. A necessary step towards this objective is consolidation of the technology. For this goal, adequate (international ) standards should be available. From this viewpoint the objective of the present project is to obtain experimental evidence in order to validate and if necessary improve the existing (international) standards for small standalone wind turbines.
The information will be useful for the official European standard bodies (CEN/CENELEC) in the accelerated process of development of standards for wind turbines.

The deliverables consist of a report containing the following: - example calculations of different types of machines with IEC simplified method and more sophisticated calculation models;
- description of the test methods used;
- results of the measurements (loads, power and other relevant turbine parameters);
- guidelines for interpretation of the standard to be used by designers and certifying bodies;
- recommendations for improvement of the IEC document;
- recommendations to CEN/CENELEC for standardization of small wind turbines.

The project aims at the improvement of the quality and safety standards of small standalone wind turbines. A draft international standard for small wind turbines has been prepared by IEC. This standard contains simple rules for the structural design suited for manufacturers with limited access to sophisticated design methods. The aim of the project is to validate these rules by measurements. It is expected that the IEC standard will be adopted by the European standardization bodies. A European standard will serve the needs of the many companies in Europe that are manufacturing small machines, by enhancing the quality and reliability level. It will contribute to the improvement of the market position of small wind turbines in the vast niche for small standalone systems. This market is situated especially in the isolated and remote regions, both inside and outside Europe. The systems will serve the energy needs of many users who still are deprived from the services of an electrical power network.

The proposed design rules for small wind turbines in the IEC draft allow to calculate the mechanical stresses in the main components of the wind turbine (blades, shaft, support structure), caused by extreme and fatigue loading. Within the present project, measurements are carried out on three small commercial wind turbines of different design. The machines are located on different test stations in Europe: an Wenus Inventus 6 machine at the DEWI test station in Germany, a Proven WT2200 machine at the test station of NEL in Scotland and an LMW 1003 machine at the test station of CRES in Greece. Mechanical loads are measured in blades, shaft and tower, together with other quantities necessary for the evaluation (wind data, electrical power, etc.). The measured loads will be compared with the values calculated for the specific designs according to the simple method of the draft IEC standard. From the comparison, conclusions will be drawn for a refinement of the international standard and towards the Essential Requirements of the applicable European Council Directives.

Funding Scheme

CSC - Cost-sharing contracts


Westerduinweg 3

Participants (4)

Centre for Renewable Energy Sources
Km 19Th,marathonos Avenue
19009 Pikermi Attiki
Ebert Strasse 96
National Engineering Laboratory (NEL)
United Kingdom

G75 0QU East Kilbride
Frederiksborgvej 399