To address the issues of the lack of an analytical model for oscillation centers and the migration of oscillation centers in power systems with different forms of DC integration after being disturbed

this paper proposes a non-autonomous admittance substitution method

based on an impedance perspective

to describe the impact of multiple DC integrations on the AC grid. The method begins by considering the operational characteristics of DC systems

making approximate assumptions from an impedance perspective

and constructing an analytical model for oscillation centers in a system with a single DC integration. This transforms the impact of DC integration into an effect on the impedance of the system's tie-lines. Next

impedance circle diagrams are used to analyze and conclude that the oscillation center will shift toward the receiving end after DC integration. Subsequently

based on the single DC integration model

parallel models for multiple DC integrations and models for DC systems within coherent groups are constructed. The patterns of oscillation center migration are analyzed on the basis of variations in system parameters. Finally

the correctness of the equivalent method and the patterns of oscillation center migration after DC integration are validated through simulation examples using an improved hybrid AC-DC CSEE-RAS79 node system.