Posters

Abstract

Wind farm developers and owners may have wind sector management or curtailment applied to their turbines by the grid operator (for power export control) or the turbine manufacturer (for load control). It is desirable to obtain an in-house or independent assessment of such a scheme or to design ones own scheme for operational objectives such as loads reduction (or cost estimation) for lifetime extension, but the input data and associated tools are hard to obtain, complex and may be computationally intensive, requiring careful treatment. This method presents a pragmatic approach utilising data available to wind farm owners and generic loads models such that it can be explored without the need for turbine manufacturer data. This paper presents the design and a worked example for a pragmatic method to generate a wind farm wind sector management scheme for the purpose of loads management and life extension cost estimation. The aim of this work is to provide an approach accessible to wind farm developers and owners that can be utilised for site suitability studies and where extended life operation is under consideration (and initial results do not predict that turbine components can achieve the desired lifetime). The method employs a pre-calculated database of wind turbine fatigue loads, generated using a generic aero-elastic turbine model, which is used to calculate the contribution from each wind direction sector based upon the local site specific conditions including internal farm wake effects. An input power curve and frequency distribution is employed to estimate the associated energy contribution from each direction sector. For operational wind farms consideration is made for prior years of operation and legacy component fatigue. The methodology then calculates the desired fatigue life consumption rate based upon the historic fatigue level and the target operational lifetime of the wind farm. The desired fatigue consumption rate then dictates how much the fatigue loads must be reduced by the wind sector management scheme. The wind sector management scheme is then optimised to achieve the desired fatigue life consumption rate whilst minimising the lost production and a calculation of overall lifetime energy balance is reported, with the aim that there is a net gain in overall lifetime energy with the wind sector management scheme employed. The resultant wind sector management scheme can be utilised as a starting point for further discussions on implementation with the wind turbine manufacturer, or can be used to estimate the additional investment (proxied as the revenue associated to lost production) associated to extended lifetime operation. This approach could be extended to include wind farm curtailment design (turbine derating) which is increasingly relevant to wind farm operation as wind capacity on the grid increases and grid curtailment during high supply/low demand periods is necessary.