Virtual Model Development of the Load Application System of a Wind Turbine Nacelle Test Bench for Hybrid Test Applications

The existing nacelle testing methods require continuous improvements to satisfy the ever-increasing demands for testing modern wind turbines. One way to achieve this goal is to use advanced simulation techniques to undertake hybrid testing, in which experiments and simulations are combined to push the boundaries of nacelle testing even further. To do so requires the development of a virtual model of the test bench featuring the true test bench dynamics and functionalities. This contribution presents the development of a virtual model of the complete nontorque load application system of a nacelle test bench at Fraunhofer IWES. The model development methodology is explained and the impact of different levels of modeling depth of the hydraulic system model is investigated. It is concluded that modeling of friction and valve dynamics is necessary as they have significant influence on the generated loads. These findings can help in the development of virtual models of nacelle test benches and pave the way for performing hybrid testing for wind turbine nacelles.