Date of Award

December 2020

Document Type


Degree Name

Doctor of Philosophy (PhD)


Electrical Engineering

Committee Member

Pierluigi Pisu

Committee Member

David Schoenwald

Committee Member

Randy Collins

Committee Member

Sukumar Brahma


The growing interest in battery energy storage systems (BESSs) at both small-scale and large-scale levels in power grids highlights their significant roles in future power grids. The future grid in the presence of renewable resources such as hydro-power, wind, and solar energy face two major technical challenges; location of potential renewable sources and uncertainty, which can cause serious issues such as blackouts in power systems. However, in both cases, BESSs is one of the promising solutions. While small-scale battery energy storage systems can decrease the need for long-distance heavy load transportation in the power system, which is one of the primary reasons for the blackouts, large-scale BESSs can provide load frequency control to their fast response. A well-managed large-scale battery integration to the power grid reduces load flow deviation in the tie-lines and frequency oscillations caused by small load disturbances. In general, the battery’s small time-constants, fast response, and high energy density creates a large spectrum of potential applications for BESSs in power systems. This thesis focuses on the battery integration to the power system in both distribution and transmission level to evaluate its potential impact on power grid; then, it focuses on the frequency regulation by taking the advantage of the small-scale and large-scale batteries. The first part of this research investigates the small-scale battery integration to the power system in the distribution level and its potential effects on the transmission level's frequency deviation. It is shown that the higher penetration level of the renewables can cause serious issues such as overvoltage, thermal, and frequency deviation issues in the distribution and transmission levels under current tariffs. The load profile's sensitivity to the battery characteristics and its efficiency, and electricity tariffs are studied. Then, tariff modification as one of the promising tools for load profile adjustment is introduced to modify the customers' load profile and mitigate the frequency deviation. The results under modified tariffs are compared to the frequency control results in a small microgrid using model predictive control. In the second chapter, the effect of those new loads on the power flow and inter-area oscillation modes are studied. Then a servomechanism controller is designed to damp the inter-area oscillations. Considering the small time constant of the large-scale battery, we model a large-scale battery integration to the power system to study the effect of its integration on the power system's stability. Finally, centralized and decentralized hybrid controls are designed on the inverter's firing angle to manage the large-scale battery's active and reactive power to damp the oscillations. Results show a notable improvement on frequency deviations.



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