Position: PhD Candidate
Current Institution: University of Michigan
Abstract: Safety and Stability of Future Smart Grids: Managing Uncertainties of Distributed Energy Resources
Power grids are currently undergoing drastic changes from centralized fossil fuel-based generations to renewable resources and distributed energy resources (DERs). However, it is clear that the current grid infrastructures and control schemes are not yet ready for such changes. First, renewable DERs are intrinsically variable and uncertain. Second, DERs usually connect to the grid through inverter interfaces, which demonstrate different dynamic characteristics than traditional power plants. Third, DERs are typically small in capacity and are deployed distributedly, rendering hundreds of millions of control points. I envision that future energy systems will evolve into integrated systems of microgrids and my research propose a framework to verify and synthesize safety and stability for networked microgrid systems.
To begin with, renewable DERs, such as solar photovoltaic and wind generation introduce uncertainties to the system and therefore pose great difficulties for safe system operation. In this work, the impacts of uncertainties on system dynamics are analyzed in the context of reach-set computation. We develop theoretical bounds to quantify all possible system behaviors under uncertainties. The proposed method constructs the second-order trajectory sensitivity and exploits the mathematical tool of logarithmic norm.
Apart from verifying safety constraints through analyzing the impacts of uncertainties, we proceed to synthesize safety-ensuring control laws for inverter-interfaced DERs in microgrids. We apply barrier functions-based method to compute distributed and decentralized control laws that certify satisfaction of voltage constraints during transients. Algorithmic constructions of these control laws are proposed using sum-of-squares optimization tools.
Sijia is a PhD candidate in the ECE Department at the University of Michigan advised by Prof. Ian Hiskens. Sijia earned her M.S. in Mathematics from UM in May 2021 and is expected to receive her PhD in December 2021. Sijia‘s research interests include dynamics and control of networked systems renewable energy and emerging smart grid technologies. Her dissertation research addresses critical challenges including uncertainties stability and safety issues that are arising with grid-integration of distributed energy resources. Her research is also seeking to promote renewable energy particularly through interconnecting multiple energy carriers. Sijia recently received the prestigious Barbour Scholarship from UM and was the recipient of Forrest Graduate Student Fellowship. She received honorable mention for the Towner Prize for Outstanding Ph.D. Research and was a finalist of Marian Sarah Parker Prize. Besides research Sijia has a record of leadership roles in the Graduate Society of Women Engineers at UM.