Robust Practical Stability Region Partition Considering Parameter Uncertainty and Volatility for Direct-Drive Wind Power System

A power system is a strongly nonlinear dynamic system, and traditional small disturbance stability analysis cannot reflect the dynamic characteristics of the system under uncertain disturbances. This paper proposes a robust practical stability region (RPSR) partitioning method that considers uncertain disturbances to address the uncertainty of wind power injections and load volatility in wind power systems. First, a disturbance model of the wind turbine generator access system is constructed on the basis of perturbation theory to investigate the effects of uncertainty disturbances on the dynamic characteristics of the system. Second, through bifurcation analysis and limit cycle (L-cycle) tracking, a comprehensive bifurcation diagram that considers the variation trend of the L-cycle amplitude is drawn. Combined with the variation trend of the L-cycle, the RPSR of the system under uncertain disturbances is partitioned. Case studies of dual-machine system and multimachine system explore the new concept of the RPSR. Last, numerical simulations are used to verify the effectiveness of the analysis results and the proposed method.