Model-based Control Strategies applied to distribution grids in local energy communities

Abstract

This Ph.D. dissertation provides a collection of tools and methods performed since 2017 at the Austrian Institute of Technology, in association with the Institute of Mechanics and Mechatronics, Vienna University of Technology. The research was conducted within the Blockchain Grid (FFG No. 868656) project funded by the Austrian Research Promotion Agency. The publications resulted from the cooperation between the Austrian Institute of Technology, Siemens AG Österreich, Energienetze Steiermark, and Vienna University of Technology.This Ph.D. presents research on control and optimization of the distribution grid and integrated energy assets in a local energy community. It also offers a solution to reconcile the physical settlement issue that a local energy market faces in a distribution grid by providing a method to limit the flexibilities to ensure overall grid security preemptively.For several years, the amount of intermittent distributed energy resources (DER’s) like photo-voltaic systems, wind generators, and new loads like electric vehicles, electric and thermal storage, and heat pumps has increased in distribution grids. Power system tools like load and optimal power flow, designed for transmission grids, are applied to distribution grids with limited or no modification. Since DER’s and loads directly depend on weather factors like ambient temperature, irradiation, and other external disturbances, they, in turn, affect the performance of these tools. Therefore, novel optimal grid control methods are to be developed which are compatible with distribution grids.This dissertation presents a novel three-phase unbalanced holomorphic embedding load flow method in conjunction with a non-convex optimization solver. Additionally, a novel three-phase unbalanced model-based energy management system is presented to manage the flexibilities that a smart home can offer. A control scheme is introduced to derive relations between the grid level optimal power flow and individual flexibility controller consisting of energy management systems. All the methods are demonstrated at a pilot in Heimschuh, Steiermark, Austria.