Grid Impact of a 20 kW Variable Speed Wind Turbine

The power quality impact of a 20 kW direct-driven variable speed wind turbine equipped with passive blade pitching has been investigated. The electrical system of the turbine consists of a 66-pole permanent magnet synchronous generator, a diode rectifier and a thyristor inverter. The turbine causes a relatively high flicker in the medium wind speed range, but small changes in the dc-link can reduce this. The voltage distortion is small while the harmonic current injection reaches 10 % at rated wind speed. The investigation also shows that the passive pitch system allows high power qualit