Transient Stability of Power Grids Comprising Wind Turbines: New Formulation, Implementation, and Application in Real-Time Assessment

Enhancing penetration of wind turbines in the modern power grids, the assessment of the transient stability has changed to a more complicated issue. This paper proposes an innovative real-time method based on the corrected kinetic energy, which aims to assess the transient stability of a power system comprising wind turbines by calculating critical clearing time. To enhance the accuracy of the calculations, the proposed method utilizes structure preserving for taking details of the network model into consideration. Moreover, a new indirect calculation method based on Taylor expansion of the rotor angle is proposed, which considers the effects of the wind turbine generator controllers on the corrected kinetic energy calculation. Specifically, the latter indirect calculations take the effects of the potential terms of transient energy function into account for calculating critical corrected kinetic energy. Also, the latter method considers the fault-on trajectory impact on the transient stability assessment and simultaneously avoids heavy computational burden, and as a result, it guarantees accurate real-time assessment of transient stability. The simulation results show that the proposed method calculates the critical clearing time of wind turbine generators with notable precision and very good speed, and consequently, it is sufficient for transient stability assessment of power grids comprising wind turbines.