A power output and mechanical model of a wind turbine and its control strategy under severe wind conditions

Abstract

Under the current wind turbine control strategy, wind turbines are cut off to guarantee their safety for wind speeds exceeding 25 m/s. However, under severe wind conditions, power grids with high wind power penetration will suffer a catastrophic consequence due to the large-scale cut-off of wind turbines. To solve the problem, mechanical effects on a wind turbine from the aspect of airflow are analyzed in this paper; a numerical connection between the thrust coefficient and the wind power coefficient is proposed. On the basis of those analyses, the accumulated load on the blades and the tower of the wind turbine are analyzed, and a cohesive control strategy is proposed. The strategy uses real-time wind speed data to calculate the mechanical load on a wind turbine and realizes the maximum active power output under severe wind conditions. The results of case studies verify the effectiveness and superiority of the proposed strategy.