Application of non-stationary iterative methods to an exact Newton-Raphson solution process for power flow equations

AC power flow problems are usually solved by the Newton-Raphson solution method. The main step is the linearization of the nonlinear power flow equations and the subsequent solution of this linear system. The characteristics of this linear system of equations vary for different power flow implementations; symmetric/unsymmetric, positive definite/indefinite system matrices can result. Based on these characteristics, different direct and iterative linear system solvers can be used to maximize performance and solution robustness. In this paper, results are given of nonstationary iterative methods for unsymmetric, indefinite linear systems derived from power flow equations