The convergence adjustment of power flow plays an important role in the safe and economical operation of a power system. A convergence adjustment method of power flow based on node type switching is proposed to deal with the non-convergence situation of power flow calculation due to the imbalance of reactive power. In the case of non-convergence of power flow

all PQ nodes of the system are set to PV nodes and then these nodes are gradually recovered according to the proposed reactive power vacancy index. Finally

the nodes that cannot be recovered are determined

which provides an adjustment basis of power flow to the staff and lays a foundation for rationality adjustment of power flow. The analysis results of an IEEE 39-bus system and Shaoguan City system have verified the validity of the proposed algorithm and the adaptability of the large-scale power grid.