Dynamic Equivalence Method of DDPMSG Wind Farm for Sub-Synchronous Oscillation Analysis

Single or multiple wind turbine generators (WTGs) model have already been used in sub-synchronous oscillation (SSO) analysis. However, there is little researches on the equivalence method of wind farm (WF) for the SSO study. The general equivalence method may lose the weak damping SSO mode. In this paper, a DDPMSG WF multi-machine equivalence method is proposed for SSO analysis. According to their SSO modes, the DDPMSGs are grouped in two steps. The oscillation frequency or damping is only considered in each step. The parameters of equivalent DDPMSG model are calculated by aggregation in each group. Furthermore, an online application processing method is proposed. The simulation verification is carried out based on small signal model and electromagnetic transient model of WF. The results show that the weak damping SSO mode of WF is well preserved in the proposed method.