Power flow obtaining method applicable to AC and DC system

The invention discloses a power flow obtaining method applicable to an AC and DC system. The power flow obtaining method comprises the steps of: firstly, establishing an AC and DC power system power flow model including an AC network model, a DC network model and a converter model, then, relaxing the AC and DC power system power flow model to a second-order cone form by adopting a cone relaxationtechnology, and finally, on this basis, obtaining a piecewise linearization AC and DC power system power flow model according to a second-order cone linearization method, wherein the linearization precision can be adjusted through a zooming method and changing of a piecewise number index. According to the power flow obtaining method applicable to the AC and DC system disclosed by the invention, the cone relaxation technology and the second-order cone linearization technology are adopted; the original non-convex nonlinear AC and DC power flow equation is converted into the convex piecewise linearization form; the operation economy of the whole AC and DC system can be improved; and simultaneously, the power flow obtaining method is also more suitable for processing all kinds of operation optimization problems having relatively high timeliness requirements in the power system.