Abstract
This thesis consists of research on modeling practices for subsynchronous control interactions (SSCI) involving doubly-fed induction generator (DFIG)-based wind turbines (WTs) and series-compensated transmission lines. Most of the SSCI analysis performed uses impedance-based techniques, with a focus on developing modeling practices for screening studies. Background is given on wind energy (Chapter 2), DFIG-based WT design and control (Chapter 3), and series compensation (Chapter 4). Real-world instances of SSCI and popular methodologies for SSCI analysis in both academic and industrial settings are discussed (Chapter 5). The primary contribution of this thesis is a large-scale sensitivity analysis involving 379M unique SSCI scenarios—13,172 unique grid equivalents and 28,800 unique WT equivalents. This results in a comprehensive assessment of how various aspects of grid (Section 7.2) and WT design (Section 7.3) relate to their respective subsynchronous impedances. The two impedance characteristics are summed and screened for SSCI (Section 7.4) to understand how study variables contribute to SSCI performance, providing insight into the mechanisms most relevant to SSCI and establishing numerous simplifications that can accelerate future studies. Another noteworthy contribution is the introduction of a new frequency scanning technique (Sections 6.2 and 7.3) that is roughly an order of magnitude faster than the traditional approach.