Study of DFIG Differential Protection Including Analysis of Interturn Faults
DFIG, differential protection, Park components, wind power generation, inter-turn fault.
With the increase in interest in renewable energies in the world, the importance of research in wind energy, methods, and associated technologies has grown. The increase in wind turbines connected to the electrical systems also brought with it new challenges related to the stability of the system and protection of its components. Differential protection is used in many electrical system components and for DFIG-based wind turbines this protection has been proposed recently. Therefore, this work proposes criteria in the decision-making of the differential protection based on the Park transform, which in addition to the restriction current also uses the voltage level and the direction of the currents at the stator terminals. In a simulation with DFIG operating at 1.51 MW, tests were carried out for internal and external faults to the protection zone, of the single-phase and threephase type with different levels of voltage drops. Inter-turn faults on the machine’s rotor and stator have also been tested with varying levels of defects. Thus, with the proper def inition of the operating logic, it was possible to show the effectiveness of the protection, with detection for all single-phase and three-phase faults within the protection zone, detection of faults in windings in the stator with 10% defect or more and detection of faults in the rotor windings with a defect of 20% or more.