Reader’s Guide to Sub-Synchronous Interactions in DFIG-based Wind Parks

In recent decades, a considerable amount of literature has focused on the sub-synchronous interaction (SSI) of doubly-fed induction generator-based wind park (DFIG-WP) with series capacitor compensated transmission grid. Nevertheless, the new investigator or uninitiated reader interested in this topic needs guidance on approaching the vast amount of written material on this complex phenomenon. This paper reviews the real-world incidents, instability mechanism, analysis methods, and mitigation of the SSI in DFIG-WP. The sub-synchronous control interaction (SSCI) rather than induction generator effect (IGE) is clarified as the main form of SSI in DFIG-WP. In practice, the impedance-based stability assessment (IBSA) based on electromagnetic transient (EMT)-level frequency scanning is recommended to detect the potential SSI risks with the black-box manufacturer-specific models. Although the SSI study has lasted for years, bypassing the series capacitors is still the primary solution in real-life incidents. Hence, a supplementary damping controller (SDC) considering the practical implementation challenges is the future trend to properly solve SSI issues, and data-driven techniques might be utilized. The pertinent references are cited to provide directions for gaining in-depth knowledge.