ECN publication
European wind turbine certification EWTC : guidelines for design evaluation of wind turbines
Hulle, F.J.L. van; Nath, C.; Jensen, P.H.; Eriksson, C.; Vionis, P.S.
Published by: Publication date:
ECN Wind Energy 1-8-2001
ECN report number: Document type:
ECN-C--01-059 ECN publication
Number of pages: Full text:
44 Download PDF  

The main objective of EWTC is to develop a common practice in order to overcome the different interpretation possibilities of the present standards used in certification i.e. the IEC 61400-l which addresses technical and safety requirements for wind turbines and the IEC WT 01 which addresses the certification systems. The use of these documents - which contain a lot of sub-optimal compromises - in practice lead to different interpretations and hence to different conclusions in the evaluation of wind turbine design. As a result, wind turbines are not universally accepted. The ultimate objective is to work towards a uniform wind turbine certification all over Europe.The basic method followed in the EWTC project was to identify the variation in interpretation by in parallel carrying out three ?certification cases?. Based upon the differences encountered the project partners have worked out solutions for agreement. The result of this process is a set of Guidelines to be used together with the above-mentioned IEC standards and other Certification Regulations used by the Certifying Bodies. The project was carried out by a Consortium consisting of Germanischer Lloyd WindEnergie (D), Riso National Laboratories together with Det Norske Veritas (DK), Centre of Renewable Energy Sources CRES (GR) and Energy research Centre of the Netherlands ECN together with CIWI Holland. The coordination was done by ECN. The manufacturers Enercon GmbH (D), Nordic Wind Power (S) and Jeumont Industrie (F) provided the material for the case studies in terms of design documents and access to a wind turbine for testing. The case studies delivered a lot of discussion material and hence aspects to be clarified in Guidelines. As expected, the differences in evaluation methods between the project partners are considerable. Striking :xamples are the different evaluation methods of the loads and the different methods for evaluation of the wind turbine protection systems. In practice it appears that the level of detail of information required from the manufacturer is quite variable, and a similar variation of detail is visible in the evaluation reports of the Certifying Bodies. The partners have streamlined their conclusions towards a common document: Guidelines for Design Evaluation. These Guidelines will be used on a voluntary basis by the partners who participated to the project together with the documents, which are part of the formal set of certification regulations. The implementation of these Guidelines in a formal European system should take place after some experience has been collected. However it should not be assumed that this would happen automatically without a proper external mechanism hat will maintain continuity in the harmonisation process.

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