Propagation of Flicker in Electric Power Networks Due to Wind Energy Conversions Systems

Wind Energy Conversion Systems (WECS) produce fluctuating output power, which may cause voltage fluctuations and flicker. Flicker assessment in networks may be difficult, since its evaluation requires long computing time and special procedures to calculate the flicker severity index, Pst. A frequency domain method to study flicker propagation is presented. This method is based on propagation of frequency components from WECS output currents throughout the grid. In this way, a fast flicker analysis in a network of any size can be performed. An algorithm for flicker measurement in the frequency domain, which allows Pst calculation, is proposed. Several study cases were performed, and results are compared with time domain simulations, showing good agreement between them.