Design Principles for Wind Turbine Earthquake and Wind Load Combinations

With the ongoing changes in the modern world, the usage of renewable energy sources is increasing. The negative impact of fossil fuels on global warming has led to the search for clean energy sources. Wind energy, which is the most widely used of those sources, is discussed in this study. Numerous studies have been undertaken in this regard, but seismic effects are only newly being considered. In addition to having strong wind zones, Turkey is located in a geographical position through which active fault lines pass. The presence of high wind zones overlapping with these fault lines necessitates seismic analysis for turbines planned to be built in the country. Analysis of wind and seismic load simulation is difficult with traditional structural design programs. In this study, coefficients including wind loads are suggested for civil engineers who plan to analyze wind turbines with only seismic effects. For this purpose, a horizontal axis steel wind turbine with a 5 MW scale is analyzed in this work considering a series of wind and seismic loads in the area around Gelibolu. These environmental effects are evaluated under different operating conditions of the turbine, including normal operation with no earthquake loads, park condition with earthquake loads, idling condition with wind loads, normal operation with earthquake loads, and idling condition with earthquake and wind loads. The full system model of the turbine is developed with the FAST finite element program employing a special code for wind turbines developed by the National Renewable Energy Laboratory. As a result of the analysis, it is concluded that seismic loads acting with the wind significantly change the internal forces. Damping effects occur when seismic and wind loads act at the same time. For this reason, wind loads need to be reduced by a certain coefficient in some cases. Coefficients are proposed here for application in initial designs and load combinations for certain wind and earthquake conditions.