Modified Method to Determine Small Signal Stability Region Boundary for Power System with DFIG

Despite providing advantages to the grid, large-scale wind power penetration causes system stability problems. To solve this issue, some researchers have applied stability analysis to a wide area of operation, namely the small signal stability region (SSSR) boundary. However, some boundary points of the SSSR result in a positive real part of the eigenvalues, indicating unstable conditions. Therefore, a study that guarantees stability in the power system is necessary. This study proposes a modified method for determining the SingSR boundary, which guarantees stability within a wide range of operational areas and ensures that every boundary point has a negative real part of the eigenvalues. This study used a four-bus test system modeled in DIgSILENT PowerFactory and a type 3 wind turbine generator, the doubly-fed induction generator (DFIG). This research also investigated the effects of the automatic voltage regulator (AVR) and DFIG operation type using the modified method developed. The results of the simulation demonstrate that the proposed method successfully guaranteed stability at each SSSR boundary point, as indicated by the negative real part of all eigenvalues. This study presents a new approach for investigating the wind power integration's effect on small signal stability.