The increasing share of converter based renewable generation is changing the dynamic behavior of modern power systems. In this context, grid forming (GFM) converters are considered as one of the technologies that aim towards the stable operation of electrical grids based on renewable energy sources, such as wind energy. With this technology turbines will interact with the grid through a wider range of system events, introducing the structure to new electrical and mechanic dynamics. This work investigates the mechanical loads of wind turbines during grid events such as inter-area oscillations, phase angle jumps and frequency deviations.

The study uses open-source grid forming inverter and wind turbine data to simulate the dynamic behavior of wind turbines operating with grid forming control strategies. A set of representative grid events are simulated using Matlab Simulink GFM Virtual Synchronous Machine (VSM) model, which is combined with OpenFAST aeroelastic simulations to analyze the turbine load under constant and turbulent wind conditions. The methodology enables the analysis of the system response and the assessment of mechanical load implications of grid forming control under realistic wind and grid disturbance conditions. In addition, the coupled simulation environment provides a basis for future investigations of the interactions between turbine mechanical control and inverter control, which may affect the resulting power output and turbine structural response. The analyzed disturbances include voltage phase angle jumps, inter-area oscillations, and Rate of Change of Frequency (ROCOF) events, which represent critical perturbations commonly considered in compliance testing are performed according to specifications defined in European grid codes for different virtual inertia constants of the VSM.

During such conditions, the grid-forming control responds by rapidly adjusting the active power output, leading to fast changes in generator torque within the turbine drive-train. These torque variations translate into increased structural loads on the turbine. The simulations show that blade root edge-wise and tower side-to-side bending moments are especially affected. In particular, frequency related events show that higher virtual inertia in the VSM contributes to increased tower side-to-side loads, indicating a trade-off between grid support capabilities and turbine structural loading. The results demonstrate that the combined electrical and aeroelastic simulation framework enables the assessment of the structural dynamics of grid-forming wind turbines. Consequently, highlighting that the tuning of grid-forming control parameters such as virtual inertia, should consider the impact on turbine structural loads, in addition to grid stability requirements.