Modelling and operating characteristics of direct drive wind farm connecting to power grid

The electromechanical transient model of direct-drive wind farm is built through the reasonable simplification of electromagnetic transient model and its engineering application is realized through power system analysis software package (PSASP) user-defined (UD) model widely used in China. The transient characteristics of direct-drive wind farm connecting to power grid are acquired by combining theory with example analysis especially low voltage ride through (LVRT). Simulative result shows that the voltage of bus which wind farm access and frequency of power system is effect by the wind farm; Characteristic of LVRT can improve the level of frequency stability of power system. Reactive power compensation device and conventional power supplies who have frequency modulation ability must be installed, which can reduce influence on power grid.