Low voltage ride through capability enhancement of fixed speed wind generator

Fixed speed wind turbine generator system (WTGS) uses induction generator as wind generator. Besides some of its advantages, it suffers greatly to meet the requirements of new wind farm grid code due to the dependency on reactive power. Some flexible AC transmission systems (FACTS) devices have been proposed recently for compensating the reactive power of induction generator during network disturbances. However, integration of FACTS devices to wind farm definitely increase the overall cost. Therefore, in this paper, we focuses on a new topology, where fixed speed WTGSs are installed in a wind farm with variable speed wind turbines (VSWT) driving permanent magnet synchronous generators (PMSG). VSWT-PMSG uses a fully controlled frequency converter for grid interfacing and it has abilities to control its reactive power as well as to provide maximum power to the grid. Suitable control strategy is developed in this paper for the frequency converter of VSWT-PMSG. A real grid code defined in the power system is considered to analyze the low voltage ride through (LVRT) characteristic of fixed speed WTGSs. Simulation results clearly show that the proposed topology might be a good solution to augment the LVRT requirement of fixed speed WTGSs.