An analysis of transient characteristics of interconnected wind power generation system with DFIG

As the major energy conversion technology for large wind turbine, Doubly Fed Induction Generators (DFIGs) will soon play an important role in the future power system in both economic and system reliability regards, just as synchronous generators in nowadays. Unfortunately, the transient behavior of a DFIG is not as well understood as those of a synchronous generator, or its twin brother, Doubly Fed Induction Motor (DFIM), especially when a DFIG is connected to a finite bus where the voltage varies with the imported power. This paper presents a study on the transient characteristics of a power generation when the power is generated from wind turbine using DFIGs. The transient behaviors of active power, reactive power and voltages in a wind power generation system are analyzed. In particular, we try to find out whether the active power, reactive power, voltages and rotor movement are well behaved during the transient period when the system changes from one steady-state to another under disturbances. This work is important in that the transient characteristics of DFIGs are essential to many system operations and analysis, such as Power/Voltage analysis (PV curve). Our study shows that PV curve is valid under unit step disturbance of wind speed and the convergence rate to the new equilibrium point is dependent to the current load power.