Minimum voltage protections in variable speed wind farms

The transient behaviour of a power system with a doubly fed induction generator (DFIG) and a synchronous generator is studied. The DFIG is equipped successively with two minimum voltage protections, the first is a minimum voltage threshold, the second is a minimum voltage threshold followed by auto-reclosing of the generator. The evolution of output power, terminal voltage, rotor speed and system frequency is discussed. Results show how auto-reclosing of DFIGs could help to maintain voltage and frequency after a severe fault.