Optimal Planning Method for Power System Line Impedance Based on a Comprehensive Stability Margin

With the increasing scale of power systems and the large-scale application of new energy technologies, the planning and construction of future power grids and the stable operation of systems face severe challenges. Among them, transient stability and short-circuit current are two key factors that determine the safe and stable operation of a power system. However, in traditional power-grid planning, there is little research on the strategy of coordinating the solution between transient stability, short-circuit current problems and planning forecasts. Based on the perspective of power-grid planning, this study proposes a method for the optimal planning of a power system's comprehensive stability margin that uses the external penalty function method. The coupling relationship between the transient stability margin and short-circuit current margin is developed through the system impedance in power-grid planning, and the line impedance optimization planning problem based on the comprehensive stability margin is formulated as a multiobjective optimization model. Finally, the optimal system impedance and the optimal comprehensive stability margin are determined by the external penalty function method. The simulation results of an IEEE 10-generator 39-bus system verify the effectiveness of the proposed method, and the system with the optimal planned impedance determined by this method yields the best comprehensive stability margin. Further simulation verification is conducted in a real power grid in China, and the strategy proposed in this article exhibits good economy and scalability. It provides a theoretical basis for the planning and construction of the future power grid, which is conducive to the safe and stable operation of the future power grid.