Control strategies for wind power systems to meet grid code requirements

This paper proposes LVRT (low voltage ride through) control strategies for wind power systems. According to the grid requirements, wind turbines should continue to operate during a grid voltage fault. LVRT control must guarantee stability under an unbalanced grid-fault condition, because a single-phase ground fault or two-phase short-circuit leads to an unbalanced voltage. This paper proposes LVRT control strategies that satisfy grid requirements under unbalanced conditions. These strategies include dynamic breaking resistor operation, detection of grid faults, and the power flow for each grid-voltage condition. Simulation results show that the proposed control strategies are effective for the LVRT control of wind power systems.