Transient stability constrained optimal power flow using 2-stage diagonally implicit Runge-Kutta method

This paper proposes a novel numerical integration method based on two-stage diagonally implicit Runge-Kutta (2S-DIRK) to solve the transient stability constrained optimal power flow (TSCOPF). The 2S-DIRK is an implicit trapezoidal method with the second-order accuracy, and its numerical stability is S-stable and then superior to other trapezoidal methods. Therefore, the 2S-DIRK method is used in this paper to discretize the swing equations of generators, and a new TSCOPF model is developed. Benefiting from the high-performance and numerical stability of 2S-DIRK, the large-step numerical iteration can be implemented to improve the computational efficiency of TSCOPF. In order to guarantee the robustness of the proposed algorithm, the interior point method is introduced with the reduced-spaced technique to solve the TSCOPF problem. Simulation studies have confirmed the superiority and computational efficiency of proposed method compared with conventional trapezoidal methods.