Study on Fast N-1 Power Flow Calculation Method Based on Subspace Iteration Method

In order to improve the solution speed of N-1 power flow calculation,the fast N-1 power flow calculation method is introduced based on subspace iteration method.The fixed preconditioner can be obtained by using incomplete LU factorization method to decompose the jacobian matrix of the initial power flow.Newton method which combines with adaptive GMRES method to solve N-1 power flow is used.Adaptive GMRES(m) algorithm is an improved GMRES algorithm,which can adjust restart parameter value automatically and improve the convergence rate further.This method is valid and correct,which has been proved in IEEE 118,IEEE 300 bus system and 2383wp system.The results show that adaptive GMRES(m) algorithm can solve large-scale linear equations quickly,and can be used for N-1 power flow in large scale systems.