A control scheme to fulfill the grid-code under various fault conditions in the grid-connected wind turbines

This paper presents systems and algorithms for the low-voltage ride-through control of wind power systems. The low-voltage ride-through (LVRT) requirement which is included in the grid-code regulates wind power systems to maintain their operation and supply reactive power during grid fault. When the grid fault arises some problems occur in wind power systems, such as over voltage and over current by transient conditions or surplus power. This paper proposes the LVRT strategy for a stable operation of wind power systems under the grid-fault condition. Proposed LVRT methods include a fault detection method, a design of dynamic braking resistor, and a flexible power control under various fault conditions. The simulation results show a validity of the proposed LVRT strategy with a 2-MW wind power system model.