Date of Award
2026
Document Type
Open Access Dissertation
Degree Name
Doctor of Philosophy in Electrical Engineering (PhD)
Administrative Home Department
Department of Electrical and Computer Engineering
Advisor 1
Flavio B. Costa
Committee Member 1
Ana Dyreson
Committee Member 2
Bruce Mork
Committee Member 3
Chee Wooi Ten
Abstract
Inverter-based resources (IBRs) are a transforming technology shaping the future of power grids by harnessing renewable energy. The integration of such power-electronics-based technology introduces challenges to existing power systems based on conventional synchronous generators. As power systems transition toward inverter-dominated operation, conventional control, modeling, and protection approaches based on synchronous machine behavior are no longer sufficient to ensure reliable and stable operation. In particular, maintaining transient stability under current limitations, ensuring fault ride-through performance, and preserving reliable protection operation remain key challenges that require further investigation.
To address these challenges, this dissertation develops and implements control and modeling strategies for grid-forming (GFM) inverters under disturbance conditions. A full-order virtual admittance model is utilized to capture transient dynamics, as demonstrated through step response analysis, enabling accurate electromagnetic transient (EMT) modeling and simulations. Furthermore, a stability-enhanced power setpoint scheme is developed by exploiting the analytical relationship between normal and saturated current modes to determine the maximum operating angle and adaptively modify the power reference. A two-mode control strategy is also proposed to mitigate loss of synchronization by preserving voltage-source behavior under current saturation. The proposed methods are validated using real-time simulation platforms under varying disturbances and show improved transient stability and fault ride-through performance compared with conventional approaches. In addition, the impact of GFM control on distance protection is analyzed, demonstrating that inverter control modifies apparent impedance trajectories and may lead to misoperation of conventional protection schemes.
Based on these results, this dissertation highlights that future inverter-dominated power systems require adaptive control strategies that account for current limitations and dynamic operating conditions. It also emphasizes that conventional protection schemes need to be revisited to account for the control-driven behavior of IBRs. The insights provided in this work contribute to advancing the state of the art in modeling, control, and protection of IBRs, and support the development of stable and reliable operation under evolving grid conditions.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Tiwari, Shipra, "MODELING, STABILITY, CONTROL, AND PROTECTION OF GRID-FORMING INVERTERS UNDER FAULT RIDE-THROUGH CONDITION", Open Access Dissertation, Michigan Technological University, 2026.