A Static Equivalent Method Considering DFIG Grid-Connected Control Strategy

With fast increase of the renewable energy, the doubly-fed induction generator (DFIG) replaced part of thermal power units. To ensure the accuracy of the static equivalent, the impact of the control in DFIGs must be taken into consideration. However, existing studies do not consider the discrepancy of power flow with different control strategies. In this paper, the power flow based on different control strategies was calculated, then the static equivalent was established. The power flow algorithm for wind power grid connection considering the control strategy of DFIGs was established based on the DFIG model. Considering the mutual restriction of active power and reactive power in DFIGs, the final power flow model was determined in the process of solving the power flow. The reactive power sensitivity of the internal network to the external network generator was used to determine the reserved generator buses, and the admittance matrix of the system was modified to retain the structure of DFIG for static equivalence. The simulation results validate the accuracy and effectiveness of the proposed methods.