The Wind Resource

Abstract

The preparation of national and international standards containing rules for the design of wind turbines began in the 1980s. The first publication was a set of regulations for certification drawn up by Germanischer Lloyd in 1986. These initial rules were subsequently considerably refined as the state of knowledge grew, leading to the publication by Germanischer Lloyd of the 'Regulation for the Certification of Wind Energy Conversion Systems' in 1993. Revised editions were published in 1999 and 2003. Meanwhile national standards were published in The Netherlands (NEN 6096) and Denmark (DS 472) in 1988 and 1992 respectively. The International Electrotechnical Commission (IEC) began work on the first international standard in 1988, leading to the publication of IEC 1400–1 'Wind Turbine Generator Systems – Part 1: Safety Requirements' in 1994. Second and third editions, each containing some significant changes and bearing the new number IEC 61400–1, appeared in 1999 and 2005 respectively. IEC 61400–1 has now superseded the national standards referred to above. The following sections describe the scope of the IEC 61400–1 and Germanischer Lloyd requirements in outline. 5.1.2 IEC 61400–1 IEC 61400–1 'Wind Turbines – Part 1: Design Requirements' identifies three different classes of wind turbines to suit differing site wind conditions, with increasing class designation num-ber corresponding to reducing average and extreme wind speeds. The wind speed parameters for each class are given in Table 5.1, where the reference wind speed is defined as the 10 minute mean wind speed at hub height with a 50-year return period. Rigorous procedures