Impacts of providing inertial response on dynamic loads of wind turbine drivetrains

There has been a growing demand from the power industry for wind power plants to support the power system operation. One of such requirement is for wind turbine to provide ancillary service in the form of inertial response. Such service requires wind turbine generators (WTGs) to inject additional energy to the grid when the grid frequency drops to help arrest the frequency decline. Inertial response will understandably impose additional dynamic loads on the wind turbine drivetrain, which have not been given much attention so far. To bridge this gap, this paper utilizes holistic models of both fixed-speed and variable-speed WTGs that integrate the aero-elastic wind turbine model in FAST, developed by the National Renewable Energy Laboratory, with a detailed electro-mechanical drivetrain model developed in SimDriveline and SimPowerSystems. These models allow quantification of drivetrain loads at the gear-level in the midst of realistic turbulent wind and varying grid frequency conditions.