Abstract: While doing power flow calculation, most of running time spends on calculating largescale sparse linear equations Ax=b. Applied iterative methods aren’t unified in many documents, which focus only on improving the preconditioning. This paper introduces some kinds of popular Krylov iterative methods in detail, summarizes their characteristics and analyses their FLOPS and the convergence efficiency with experiments. Finally, through evaluating the computational efficiency, the most suitable Krylov iterative method for power flow calculation is be obtained.

Key words: CG, GMRES, BCG, QMR