Damping risk index for identifying sub-synchronous oscillations in PMSG-based wind farm

We propose a novel methodology for detecting sub-synchronous oscillations (SSO) in the potential instability zones that can occur during the initial vibrations of wind power generation. The proposed methodology merges frequency scanning techniques with a parallel structure, providing the time and frequency ranges in which SSO can potentially occur until the system stabilizes. It also offers a risk score for SSO that the system might encounter before stabilization. Furthermore, the proposed methodology addresses the potential instability zones during the initial start-up of the system, rather than the stability collapse zones, enabling the detection of SSO that is difficult to identify using conventional stability determination techniques. We apply the methodology to a Permanent Magnet Synchronous Generator (PMSG) wind turbine and validate it through case studies involving weak grid connections prone to SSO. Additionally, we apply the methodology to an actual offshore wind farm model connected to the mainland in the southwest region of South Korea.