Dynamic phasor modeling of type 3 DFIG wind generators (including SSCI phenomenon) for short circuit calculations

Summary form only given. The short circuit contribution of a Type 3 wind farm connected to a series compensated line is affected by subsynchronous interactions making it essential to model such behavior. Fundamental frequency models are unable to represent the majority of critical wind generator fault characteristics. The complete electromagnetic transient (EMT) models, though accurate, demand high levels of computation and modeling expertise. This paper proposes a novel modeling technique based on the generalized averaging theory, where system variables are represented using time varying Fourier coefficients known as dynamic phasors. The proposed modeling technique does not just include 60 Hz frequencies but also other dominant frequencies such as 36 Hz present due to the SSCI in the system. Methods currently used by the industry mostly rely on fundamental frequency based analysis. Only the appropriate dynamic phasors are selected for the required fault behavior to be represented. Once the SSCI behavior (waveforms showing resonant frequency at Point of Common Coupling) of a series compensated Type 3 wind farm from a real time field data is available, the developed model could be used to simulate the scenario without necessarily having to know the exact control blocks of the wind generator controls. A 450 MW Type 3 wind farm consisting of 150 units was modeled using the proposed approach. The method is shown to be accurate for balanced and unbalanced faults as well as for non-fundamental frequency components present in fault currents during sub-synchronous interactions.