Power ramp rate control and flicker mitigation for directly grid connected wind turbines

Power variation, voltage fluctuation and resultant flicker are critical issues related to the integration of directly grid-connected constant-speed wind turbines. This study introduces a methodology to enhance the quality of the power and voltage, and minimise the flicker produced from constant-speed direct-connected wind turbines. The method uses an electrolyser/fuel cell combination to be connected to the point of common coupling via limited rating converters. The control scheme is designed to keep the power ramp rate and voltage fluctuation within their limits and minimise the rating of the converters used to interface the electrolyser and the fuel cell. The incorporation of STATCOM and its effect on the generated power and flicker level have been investigated. Simulation results are carried out to demonstrate and validate the proposed technique.