Blade tip deflection calculations and safety analysis of wind turbine

Many collapse cases of wind turbines which operated in wind farms are caused by the event that blade tip hits the tower. So, one of the important indicators in wind turbine design is the tip deflection estimation. The distance from tip to the outside of the tower determines the safety of wind turbines. Usually the maximum tip deflection (also known as displacement) possibly occurs in some extreme conditions during wind turbine operation; therefore, studying of the wind turbine blade tip displacement calculation method and its safety is very essential. This paper does calculation and analysis according to standard method of IEC61400-1: E3, considering the extreme load extrapolation method and the principle of statistical probability event to put forward a new safety threshold estimation method. And with 3 MW wind turbine as an example, this paper verifies the effectiveness of the method, at the same time discusses the effect bought by the extreme turbulence model in 1.3 working condition with different c parameter´s influence on the blade tip deflection.