With the steady development of voltage source converter (VSC) and parallel DC grid based on VSC
the future power grid may become hybrid AC/DC networks containing multi-DC buses
multi-DC lines and multi-DC loads. The steady-state model and control mode of VSC are analyzed
and the power flow model of AC/DC networks containing DC grid based on VSC is derived. Then the power flow solution for DC grid with different control modes is studied prior to proposing a generalized alternating iterative power flow algorithm. This algorithm decouples the AC grid and the DC grid according to different control modes of the VSC station. In each iteration of the algorithm
AC grid iteration follows the DC grid iteration. The algorithm will not stop calculating AC and DC alternatively until the DC grid
VSC station and AC grid are all convergent. Diverse control modes of DC grid
the constraint of variables and the change of VSC control mode are taken into consideration. Finally
with the modified IEEE 57-bus AC/DC networks
several simulation results clearly verified the feasibility and effectiveness of the proposed algorithm.