Assessment of Wind Turbine for Site-Specific Conditions using Probabilistic Methods

This paper describes a new approach to assess the structural integrity of wind turbines for sitespecific conditions using probabilistic methods, taking into account the particular uncertainties associated to each site. This new approach intends to improve the site suitability analysis of wind turbines, helping to the decision making during the site assessment phase of wind farm designs.

First, the design equation for the failure mode of interest is defined, where the loads associated to the site-specific wind conditions are compared with the design limits of the structural component. A limit state equation is defined making the loads and resistance depending on a set of stochastic variables representing the uncertainties. In this paper, special focus is put on the uncertainties related to the assessment of wind data, which is the main input for the sitespecific load assessment, and can be very dependent on the site. The uncertainties on the wind properties depend on issues like the available wind data, the quality of the measurement sensors, the type of terrain or the accuracy of the engineering models for horizontal and vertical spatial extrapolation.

An example is included showing two fictitious sites with different uncertainty scenarios, which would result in a different verdict depending whether a traditional deterministic approach or a probabilistic approach is used to assess the structural integrity of the wind turbine.