Correlation Analysis of Reactive Power Control Mode of DFIG WTGs and System Frequency Stability

Although doubly-fed induction generator (DFIG) can realize the active, reactive power decoupling control by using stator flux orientation vector control technique, the choice of its reactive power control mode is still has profound impact on system frequency stability. At present, there are two control modes of DFIG, i.e., constant power factor control mode and constant voltage control mode. Through analyzing the power characteristics of DFIG WTGs, this paper presents a coupling expression between reactive control mode of DFIG WTGs and system frequency deviation, and then analyzes the impact of reactive power control mode on system frequency stability. At last, take PSS/E and WIND Package as simulation platform, the validity and rationality of theoretical analysis are verified by numerical simulation. Research results show that, whether wind speed variation, load disturbance or short circuit faults, constant power factor control mode is all conducive to system frequency stability.