Impact of distribution-connected large-scale wind turbines on transmission system stability during large disturbances

Many favorable wind resources are located in rural areas that do not have direct access to the high-voltage transmission systems. Therefore, it is practical and cost-effective to seek the installation of utility-scale, megawatt-level wind turbine generators on distribution feeders. Common study for interconnection of distributed generation typically focuses on stability impacts within the distribution feeder itself, such as the impact on feeder voltages. Efforts to investigate the impact of transmission events on distributed wind generation, as well as the impact of distributed wind generation at high penetration level on transmission stability, are much needed. This study models a power system with both the bulk transmission grid as well as distribution feeders. Megawatt-level wind turbine generators are connected to distribution feeders. Transmission disturbances are simulated to analyze their impacts on distributed wind generators. This study also investigates the reaction from all the distributed generation to a single transmission disturbance when the wind penetration is high, which could have a great impact on system stability.