Rotor current transient analysis of DFIG-based wind turbines during symmetrical voltage faults

• We theoretically analyze the rotor fault current of DFIG based on space vector.
• The presented analysis is simple, easy to understand.
• The analysis highlights the accuracy of the expression of the rotor fault currents.
• The expression can be widely used to analyze the different levels of voltage symmetrical fault.
• Simulation results show the accuracy of the expression of the rotor currents.

The impact of grid voltage fault on doubly fed induction generators (DFIGs), especially rotor currents, has received much attention. So, in this paper, the rotor currents of based-DFIG wind turbines are considered in a generalized way, which can be widely used to analyze the cases under different levels of voltage symmetrical faults. A direct method based on space vector is proposed to obtain an accurate expression of rotor currents as a function of time for symmetrical voltage faults in the power system. The presented theoretical analysis is simple and easy to understand and especially highlights the accuracy of the expression. Finally, the comparable simulations evaluate this analysis and show that the expression of the rotor currents is sufficient to calculate the maximum fault current, DC and AC components, and especially helps to understand the causes of the problem and as a result, contributes to adapt reasonable approaches to enhance the fault ride through (FRT) capability of DFIG wind turbines during a voltage fault.