Impact of different DFIG wind turbines control modes on long-term voltage stability

This paper presents a comprehensive study showing the impacts of different doubly fed induction generator (DFIG) wind turbines control modes on long-term voltage stability. The study considers fixed voltage control and power factor control modes. The analyses also consider the dynamic models of Over Excitation Limiter (OEL) and On Load Tap Changers (OLTC) combined with static and dynamic loads using time domain simulations. A hypothetical network is used for the scenario of 20% load increase. The impact of each control strategy is studied and the resulting change in long-term system stability is quantified, as well as the interactions between OLTC and OEL equipments. The results show that the manner in which DFIGs are operated will have a significant impact on system stability.