Investigation on fundamental issues of dynamic equivalent modeling of wind farms

This paper takes the GE1.5MW DFIG wind turbine as an example, to simulate and analyze the transient response characteristics of the wind turbine under different wind velocities. Three critical issues related to dynamic equivalent modeling of wind farms are summarized by intensive investigations. Firstly, the wind turbines working on low wind speed are found to consume a large number of active power during the transient process, and their transient current and active power response curves sometimes are close to ones working on high wind speeds. Consequently, the wind turbines working on low wind speeds cannot be ignored casually for dynamic modeling of wind farms. Secondly, a counterintuitive phoneme, i.e. more clusterings is not necessarily to have higher equivalent accuracy, is found, since the transient current and active power curves of the wind turbines working on various wind speeds show significant and nonlinear differences in amplitude, fluctuations and transient response time. Finally, for a large wind farm with long collector lines and complicated configurations, the equivalent network impedance, calculated by the equivalent power loss rule, is seen to be able to guarantee the consistency only during the steady-state process instead of the transient one between the detailed and equivalent models. Studies about the dynamic characteristics of the collector network impedance should be emphasized.