The power oscillation induced by the interactions between power converters and AC/DC power grids is an important stability problem faced by grid-connected renewable energy generation systems(GREGSs). Small-signal modeling is the basis for the analysis of such a problem. But the large quantities of converters with different structures

parameters and “black(grey)-box” control systems make it very difficult for the conventional method to handle the issue of system modeling. A methodology of small-signal impedance(admittance)network modeling is proposed to address the issue. With each component represented with an impedance or admittance model

a GREGS as a whole can be modeled as the network of impedance or admittance by interconnecting all the individual impedances(admittances)according to the topology of the grid. Such an impedance(admittance)network model can be further aggregated into a lumped impedance(admittance)

with which the features of the oscillation could be quantified given the frequency-dependent characteristics of the lumped impedance(admittance). Case studies on the Guyuan series-compensated wind power system have verified the effectiveness of the proposed modeling method. This work is supported by National Key Research and Development Program of China(No. 2016YFB0900104)and State Grid Corporation of China(No. SGXJ0000KXJS1500669).