Wind turbine generator dynamic performance with weak transmission grids

The location of a wind farm is selected primarily based on good wind conditions. However, these good wind conditions often coincide with relatively remote parts of the power system. This increases the need for good models and analysis, as the wind generation may represent a significant portion of the total local generation. The operation of the wind farm and its response to disturbances or other changing conditions on the power system has a very significant impact on system operation and performance. These concerns will continue to grow in importance as the amount of wind generation increases. Models for wind turbine generators have been developed and tested thoroughly. However, the impact on power-electronics based devices (like wind turbine inverters) when connected to weak systems is not as well documented. There is still some uncertainty as to the extent to which the available wind turbine dynamic models accurately describe the physical impacts on the equipment controls when operating at very low short circuit ratios (SCRs). Using a wind farm configuration loosely based on an actual wind farm, this paper investigates the effect of the SCR on the performance of wind turbine models including transient stability, low voltage ride through (LVRT), and wind farm oscillations.