An Efficient Parallel Sequential Approach for Transient Stability Emergency Control of Large-Scale Power System

Generator-tripping and load-shedding are important emergency control measures to maintain the transient stability of the power system. In this paper, emergency control is modeled as a large-scale optimal control problem. An efficient parallel sequential approach, which consists of preprocessing layer, simulation layer, and optimization layer, is proposed to solve the problem. In the preprocessing layer, power system partitioning is performed to construct a Jacobian matrix of double-layered bordered block diagonal (BBD) structure, control variable selection and initialization are designed to reduce computation cost and improve convergence. In the simulation layer, the differential algebraic equations are solved in parallel with the sensitivity analysis by reusing the LU-factorizations. Based on the BBD structure of Jacobian matrix, a parallel block algorithm is proposed to further accelerate computation speed. In the optimization layer, the resulting nonlinear programming problem is efficiently solved by predictor-corrector interior point method. The efficiency and practicality of the proposed approach are verified by numerical experiments on three test systems.