A prediction algorithm of steady frequency after disturbances for AC/DC hybrid power grid is proposed

which takes into consideration the emergency DC power support(EDCPS)and the frequency response of the AC systems on both sides of the DC link. With the linearization of the generator governor equation

the static load model equation

the transmission power equation of DC transmission system

and the network equation of power system

the prediction equation of steady frequency after disturbances in a two-area AC/DC hybrid transmission system is derived by taking EDCPS into consideration. The steady frequency after disturbances in every area of the two-area AC/DC hybrid transmission systems can be quickly and directly calculated

so that the amount of DC power support will make the steady frequency of one area reach a set value. Finally

a typical two-area AC/DC parallel hybrid transmission system is simulated. And the simulation results show that the proposed algorithm has a high accuracy and a rapid computation speed

which proves its applicability and effectiveness as well as prospects of coordinating with emergency frequency control and online application.