Date of Award
Doctor of Philosophy
Kai Sun, James Ostrowski, John E. Kobza
Natural disasters can cause widespread disturbances/power outages within distribution networks and hinder a utility’s ability to provide uninterrupted power supply to the critical public buildings (e.g., hospitals, grocery stores, fire, police and gas stations) within the utility’s serviced region. Backup generators, which are typically relied on during power interruptions, have limited capacities and have been reported to experience failures during usage. Microgrids, defined as localized power grids that incorporate distributed generators (DGs) and energy storage systems (ESSs) to allow them to operate independent of the main grid (i.e., island mode), can help utilities provide disaster relief power supply to critical public buildings during such outages. This research investigates the optimization of utility-owned microgrids assumed to be operating in island mode and supplying power to a network of critical public buildings over the course of a week-long power outage. A deterministic and two-stage stochastic model (considering only DGs), as well as a multi-stage stochastic model (considering DGs and ESSs) are developed to optimize the investment economics, reliability and resilience of the microgrids. The models provides a holistic objective function that captures the investment, fixed operation and maintenance, power supply efficiency, reliability and resilience of the microgrid in terms of a minimized total cost to the utility. This is accomplished by optimizing the location, sizing, power supply assignment and total number of DGs and ESSs within a utility-owned microgrid. Hourly and weather (cloud coverage) uncertainty in daily DG power output and critical public building demand are considered. The final DG-plus-ESS multi-stage model provides an exhaustive solution framework, that analyzes the microgrid’s reliability across all possible weather (cloud coverage) scenarios (e.g., sunny, cloudy, overcast) of a week-long outage (3,279 total scenarios).
Kizito, Rodney, "Optimization of Islanded Utility-Microgrids After Natural Disasters. " PhD diss., University of Tennessee, 2021.