Effect of Power System Flexible Operation on Static Stability Margin

[Purposes] In the new type of power system, the high percentage of new energy connected to the grid and the complex and variable load demand make the flexibility become the focus of grid operation, but the impact on the static stability of the system after regulating various types of resources to achieve the flexible supply-demand balance of the operation mode is not yet known. Thus, an optimal operation strategy that takes into account flexibility resources such as the dispatchable potential of electric vehicles is proposed and its impact on the static stability margin of the system is investigated. [Methods] First, an electric vehicle cluster flexibility supply model based on the assessment of EV dispatchable potential was proposed, and the flexibility supply and demand models of load, external grid, wind, and demand response were established; Second, a more comprehensive static stability margin index assessment system was proposed to quantitatively evaluate the impact of flexible operation on the system static stability margin according to the results of the unit output taking into account the flexibility supply and demand constraints. [Results] The accuracy and effectiveness of the proposed method are verified by the IEEE33 node system validation, through the comparative analyses of the system static stability margin trends under different scenarios.