SSCI Problem of D-PMSGs Based Wind Farm Considering Frequency Characteristics of Grid Impedance

For practical power grids, frequency characteristics of grid impedance is nonlinear and complex appearing as more than one resonances at different frequencies. The resonant frequency between nominal system frequency and twice the nominal system frequency may lead to sub-synchronous oscillation in wind farms. This paper establishes a detailed electro-magnetic transient simulation model about D-PMSGs based wind farm compensated by an SVC and considering frequency characteristics of grid impedance in PSCAD/EMTDC. Based on the model for further simulation, it comes to a conclusion that frequency characteristics of grid impedance and control parameters play a critical role in the SSO characteristics of system. The impact of the resonant frequency mentioned above is related to the grid strength and the control parameters of D-PMSG and SVC. Conclusions from this paper indicate that coordinating control parameters to weaken the effect of the resonant frequency can be a feasible solution for such a SSCI problem in practical wind farms.