Extreme wind speed analysis
High wind speeds threaten the integrity of buildings, especially those in exposed locations such as wind turbines. Therefore, safety considerations must be weighed against the additional costs of ‘over-design’. An accurate assessment of extreme wind speeds is an important factor in achieving the correct balance. An extreme wind speed analysis can be used for this purpose.
Both a wind-resistant design and a structural safety assessment require reliable extreme wind speeds modelling. The extreme wind speeds can relate to a 50-year or even a 100-year return period. When a certain amount of data on extreme wind speeds is obtained, a statistical cumulative distribution function can be used to describe the distribution status of the extreme values. Extreme wind speeds are often used to evaluate offshore wind energy areas and to determine the necessary structural strength of the wind turbine design.
Our extreme wind evaluation is based on data from wind measurements from a measurement station in or near the area (data for 12 months is required) and in accordance with IEC61400-12-1 and IEC61400-1, other applicable international standards, TR6 technical guidelines, and the latest version and internal test method BBB-PV04. The area evaluation will be carried out by applying WAsP Engineering and WindPRO. The results of the analysis will be in accordance with the ‘Site Parameter Requirements’ of the chosen wind turbine manufacturer.
Wind farm turbulence intensity
To ensure the stability of wind turbines during the average operating life (generally 20 years), a turbulence forecast is essential. Pondera calculates the turbulence intensity in accordance with DEBT and IEC guidelines, based on wind measurements in the area (if available), map material, satellite data, area inspections etc. The effective turbulence intensity is considered a characteristic parameter of the turbulence load for a given wind farm configuration in the area under investigation. This is a very important criterion to take into account in the planning process of the wind farm. The effective turbulence-intensity consists of a combination of surrounding turbulence and wake turbulence. The surrounding turbulence is generated by the general wind conditions in the area; the roughness of the terrain and the terrain profile have a significant impact on the surrounding turbulence, and to a lesser extent on an offshore wind farm. The wake turbulence is produced by the underlying effect of the turbines and is thus determined by the wind farm configuration (number, rotor diameter, distances, etc.).
Our turbulence-analysis is based on CFD analysis with the application of Windsim, on wind measurement data from a measurement station near or in the area in accordance with IEC61400-12-1 and IEC61400-1, other applicable international standards, TR6 technical guidelines, and the latest version and internal testing method BBB-PrV03. If necessary, the area evaluation will be carried out with additional application of WAsP Engineering and WindPRO. The results of the analysis will be in accordance with the ‘Site Parameter Requirements’ of the chosen wind turbine manufacturer.