Response of DFG-based wind farms operating on weak grids to voltage sags

The integration of wind power into the electrical power systems is continuously increasing all over the world. In many power systems the wind resources are located in remote areas far away from the load centres. Then the short circuit ratio (SCR) at the point of common coupling (PCC) could be small and needs special consideration in wind turbine control and operation. In this paper the authors investigate the effect of the SCR on the behaviour of wind farm following sudden voltage drop due to grid short circuits. For this a 90 MW wind farm has been simulated taking into account realistic DFG and corresponding controller implementations. The objective of this paper is to provide an insight in to the capability of DFG-based wind farm to participate in voltage support during grid faults especially in weak power systems.