Sub‐synchronous oscillations in wind farms – an overview study of mechanisms and damping methods

Abstract

Sub-synchronous oscillation (SSO) causes significant damage and performance degradation in wind farms (WFs). The root causes and mitigation methods of SSO have been identified as a result of many studies. An overview that analysed and summarised those findings in different perspectives helps optimise the existing solutions and to find alternative approaches to mitigate SSO. Therefore, a comprehensive overview of the SSO analysing techniques, mechanisms, and mitigation strategies are presented in this study. This overview is focused on the WFs based on type 3 and 4 wind turbine generators and the WFs connected to high-voltage DC transmission systems. The dominant SSO modes in each application have been presented along with the identified root cause, influencing factors, and the mitigation methods. Besides that, a comprehensive comparison between the existing mitigation strategies is presented to identify the alternative approaches and improvements. The identified improved methods are presented along with the time and frequency domain simulation results to validate their applicability. Finally, an insight into the future direction of this research is presented along with the conclusions.