REVIEW ON SUB-SYNCHRONOUS OSCILLATIONS IN WIND FARMS: ANALYSIS METHOD, STUDY SYSTEM, AND DAMPING CONTROL

More and more attention on wind farm sub-synchronous oscillation (SSO) has been paid as many SSO incidents in wind farms have occurred. This paper presents an overview of recent SSO issues in wind farm from the perspective of control, including the analysis methods, the study system, and the SSO mitigation by damping control. Three major analysis methods, as well as different study systems for wind farm SSO study, are comprehensively reviewed. The adaptability and complexity of the methods and study systems are analysed, and an overall survey of recent SSO analysis is given. Among the wind farm SSO mitigation methods, the sub-synchronous damping controller (SSDC) is one of the most commonly used methods in practice. Its configuration and signal selection are introduced in this paper

Modeling and analysis approaches for small‐signal stability assessment of power‐electronic‐dominated systems

The stability, operation, and control of power networks have been challenged due to the increased penetration of power electronic converters. New instability phenomena have appeared due to the interaction of the power converter controllers with other power network elements, including other power converters. Small‐signal tools have been proved effective to identify and mitigate stability issues but their development is still ongoing. This article presents the state of the art on small‐signal modeling and stability assessment of converter‐dominated networks. The modeling of converters and other power system components is reviewed, as well as the most common small‐signal analysis techniques employed in conventional and modern power systems with power electronics. Two case studies are introduced to exemplify the modeling and stability analysis, employing some of the techniques presented in the article