Transfer Function Sensitivity Based DFIG Shedding Scheme to Mitigate Subsynchronous Oscillation

This paper proposes transfer function sensitivity based index for doubly fed induction generator (DFIG) shedding scheme to mitigate subsynchronous oscillation. Firstly, the Phillips-Heffron model of the power system integrated with DFIG is built, and the transfer functions of DFIGs and other left part of the power system are derived. Then, the transfer function sensitivity of DFIG, which considers each DFIG as a whole part presented by a feedback transfer function, is obtained through calculating the logarithmic partial derivative of DFIG to the whole power system. Finally, the improved four-machine two-zone system with 4 DFIGs is used as the test system to verify the validity of transfer function sensitivity, the results of simulation prove that the transfer function sensitivity could quantize the influence of DFIG on subsynchronous oscillation and shedding DFIG with positive sensitivity could mitigate subsynchronous oscillation.