Study on the Influencing Factors and Mechanism of SSR due to DFIG-based Wind Turbines to a Series Compensated Transmission System

This paper investigates the influencing factors and mechanism of sub-synchronous resonance (SSR) phenomenon in the doubly fed induction generator (DFIG) based wind turbines to a series compensated transmission system. First, a model of DFIG-based wind power unit interconnected with series compensated networks is developed to analyze the mechanism of induction generator effect (IGE) and sub-synchronous control interaction (SSCI). Then, frequency scanning and time-domain simulation are performed to study how the transmission line length, series compensation degree, the capacity and the number of DFIGs, and the grid voltage level impact on SSR. The major contribution of this paper is the analysis of different influencing factors on IGE and SSCI from mechanism. Recommendations are given to practical engineering application to appropriately operate the system.