Department of Electrical Engineering Seminar
Speaker: Prof. Sairaj V. Dhople
Department of Electrical and Computer Engineering
University of Minnesota, Minneapolis
Title: Analysis and Control Innovations for Future Grids
Date : 25 February (Tuesday)
Time 4:30 PM
Venue: EE-217 (MMCR), EE Dept
Driven largely by the rapid integration of renewable resources and energy storage technologies, future grids will be dominated by power-electronics interfaces. Long-standing practices in analysis and control that were conceptualized and tuned for fossil-fuel-driven synchronous generation would therefore need to be revisited and revised. In this context, this talk focuses on advances to two problems that are fundamental to and underlie the analysis and control of power grids: power flow and economic dispatch. For the power-flow problem, we examine the distributed slack bus formulation whereby the active-power output of each generator is modeled with three elements: a nominal injection modulated by a fraction of the net-load imbalance allocated via a participation factor.
This setup acknowledges system dynamics and controllers more accurately than the conventional single slack bus, but it has long been plagued by ambiguous and inconsistent interpretations of its constituent elemental quantities. In the talk, we demonstrate that with the: i) nominal active-power injections set to be the economic dispatch setpoints, ii) participation factors fixed to be the ones used in automatic generation control, and iii) net-load imbalance considered to be the total load and loss unaccounted in economic dispatch, the power flow solution best matches results from a simulation of the system differential algebraic equation model. Shifting gears, the primary goal of real-time power system operation is to economically dispatch generation to meet net system load while regulating frequency. Presently, this is accomplished by modulating generator setpoints via a systematically engineered combination of: i) online proportional-integral control based on frequency and tie-line-flow errors (automatic generation control); and ii) offline optimization that minimizes cost of generation based on the load forecast (economic dispatch). We outline a continuous-time economic dispatch problem and a companion solution algorithm to reconcile the temporal gap that separates look-ahead dispatch and real-time control, improve market efficiency, and enhance power quality. To ensure and demonstrate compatibility, contributions in these two problems are presented first in the context of conventional grids with synchronous generation and then translated to future low-inertia grids with inverter-based resources.
Sairaj V. Dhople received the B.S., M.S., and Ph.D. degrees in electrical engineering, in 2007, 2009, and 2012, respectively, from the University of Illinois, Urbana-Champaign. He received the National Science Foundation CAREER Award in 2015 and the Outstanding Young Engineer Award from the IEEE Power and Energy Society in 2019. He currently serves as an Associate Editor for the IEEE Transactions on Energy Conversion and the IEEE Transactions on Power Systems.