Discussion of the solvability of HVDC systems power flow with a sequential method

This paper addresses the solvability of power flow for AC–DC system with sequential methods. As one of most wieldy used power flow analysis methods for AC–DC systems, this method solves the AC and HVDC systems iteratively. This paper shows that the solvability of the problem depends on a linearized coefficient matrix G, which integrated the information of the network and HVDC control modes. To analyze the singularity of G, all of the physically feasible combinations of the control modes are classified into seven categories. The conditions for the singularity of G are analyzed in detail. Systematical conditions for solvability of power flow with sequential methods for AC–DC systems are derived mathematically. Some numerical studies validate the proposed theoretical results.

► Find out the coefficient matrix G will be singular under some conditions when a linear function GX = y is used to solve the DC system.
► Classify all the combinations of control modes into seven categories including all kinds of control combinations of DC systems.
► Prove the singularity of G under these categories mathematically.
► Numerical studies validate the proposed theoretical results.