RESPONSE ANALYSIS OF WIND TURBINE STRUCTURE CONSIDERING BLADE ROTATION EFFECT UNDER WIND-EARTHQUAKE COUPLING

Most wind farms in China are inevitably built in earthquake-prone areas, and thus it is highly possible that earthquake occurs when the wind turbine is working under the wind load. This paper investigated a 2.5 MW wind turbine in Northwest China as a prototype to study the response of a wind turbine tower considering the blade rotation effect under the coupling effect of wind and earthquake. The harmonic superposition method was used to generate a simulated fluctuating wind speed considering the spatial coherence of the blade and the tower. The impeller load considering the blade rotation effect was calculated based on the blade element momentum theory, and the wake model was used to calculate the load on the tower surface in the wake area. A finite element model considering the eccentricity of the blades and the nacelle as a concentrated mass was established through ABAQUS to analyze the response of the wind turbine under wind-earthquake coupling. The influence of the input time of ground motions on the response of wind turbine under wind-earthquake coupling was discussed. The results show that the impeller rotation effect and the wake have significant influence on the calculation of wind load. The wind-earthquake coupling effect may make the top displacement of the wind turbine tower smaller than that under the wind load, and the base stress is close to that under the sole action of earthquake. The input time of ground motion has significant influence on the result when the wind-earthquake coupling is analysed and should be considered in the design.