Modeling of DFIG-Based Wind Farms for SSR Analysis

This paper conducts an analysis of subsynchronous resonance (SSR) phenomena in doubly-fed induction generator (DFIG)-based wind farms interconnected with series compensated networks. A dynamic model is developed to analyze the induction generator effect (IGE) and torsional interaction (TI) in such systems. A test system derived from the IEEE first benchmark model is considered for the analysis. The effect of two factors namely: 1) series compensation level and 2) wind speed on the IGE and TI are studied. In addition, impact of the inner current converter controller parameters and turbine parameters on SSR is also addressed. Small signal (eigenvalue) analysis is conducted to assess the damping of network and torsional modes followed by dynamic (time domain) simulations. The major contribution of this paper is the analytical investigation on SSR phenomena presented in DFIG-based wind farms interconnected with series compensated networks. The paper clearly demonstrates that IGE instead of TI is the major reason for SSR in such systems.