Reactive power control of direct drive synchronous wind generators to enhance the Low Voltage Ride-Through capability

This paper explores the performance of alternative voltage control strategy applied to direct drive synchronous wind generators, more specifically with permanent magnetic (PMSG). The reactive power control of the grid-side converter is investigated for voltage control purposes. In Brazil, the Grid National Operator (ONS) requires that wind turbines stay connected to the grid during voltage dips, but does not stipulate yet the need of reactive power injection during faults in the electric grid. It just specifies the Low Voltage Ride-Through (LVRT) capability curve for voltage dips that the wind generators should follow to avoid the trip of the under-voltage relay. Criteria of the synchronous wind generators protection are evaluated starting from short-circuit simulations in a test grid with adoption of the Brazilian grid code, without reactive power injection, being compared with those of other countries that adopt reactive power injection curves.