Implicit Function Based Open-Loop Analysis Method for Detecting the SSR Using Identified System Parameters

This paper proposes an implicit function based open-loop analysis method to detect the subsynchronous resonance(SSR), including asymmetric subsynchronous modal attraction(ASSMA) and asymmetric subsynchronous modal repulsion(ASSMR), of doubly-fed induction generator based wind farms(DFIG-WFs) penetrated power systems. As some important parameters of DFIG-WF are difficult to obtain, reinforcement learning and least squares method are applied to identify those important parameters. By predicting the location of closed-loop subsynchronous oscillation(SSO) modes based on the calculation of partial differentials of characteristic equation, both ASSMA and ASSMR can be found. The proposed method in this paper can select SSO modes which move to the right half complex planes as control parameters change. Besides, the proposed open-loop analysis method is adaptive to parameter uncertainty. Simulation studies are carried out on the 4-machine 11-bus power system to verify properties of the proposed method.