The increasing development of wind power that does not participate in frequency control leads to new challenges in the management of electrical power systems. The problems are more significant in weak power grids. The present thesis aims to evaluate the performance and the reliability of frequency response from wind turbines on a system-wide scale. Studies are applied onto an isolated power grid.First of all, the impact of high levels of wind penetration on primary reserve allocation and on grid dynamic behaviour is characterized. It is shown that the participation of wind turbines in frequency regulation is technically required for maintaining power system security from a certain wind penetration rate.Two solutions allowing wind turbines to contribute to frequency control are then studied through dynamic simulations. The performance of emulated inertia is characterized by taking into account the impact of initial wind operating point and controller parameters. The contribution of wind power reserve to system dynamic performance improvement is also identified.In order to assess the potential and the reliability of wind primary reserve, the last part of this research work is devoted to statistical analyses considering the variability and the prediction uncertainty of wind generation. Two strategies for reserve allocation are proposed and compared. The impact of forecast errors on the potential of wind power reserve is also highlighted. Finally the power frequency characteristic of a wind farm as well as the droop adjustment range is characterized
