ESTHER description

ESTHER's goal is to formulate new effective control systems adapted to consider the multi-level and multi-scale nature of power systems, overcoming the limitations due to Plug&Play scenarios. This project will be carried out by coupling the development of rigorous analytical theories with their numerical and experimental validation. We target to provide a general formulation of the problem, valid for any kind of power systems capable of being decomposed to elementary components, and to investigate ad hoc control strategies. 

ESTHER aims to obtain the possibility to describe the real operative regions for power systems, thus removing approximations while maximizing flexibility and renewables' integration. Finally, the proposed method would allow for a reduction of the design costs while ensuring design correctness, both for modern power systems and their link with the existing infrastructure.

Specific focus of the ESTHER project will be the interactions among the local, primary and secondary control levels. We aim to develop local control laws among the several devices composing a MicroGrid, that target to operate according to primary rules and secondary optimal references for power and energy while considering constraints and limitations due to the levels' interactions. 

Both generic MicroGrids and specific ones are taken into account: indeed, some tools can be developed for a general-purpose scalable MicroGrid, but they can be better specified and therefore applied to MicroGrids concerning any size or application, ranging from PV, wind farms and electric vehicles to districts. Also, the connection of MicroGrids to the main grid is of interest. Since the concept of MicroGrid is general enough to encompass several situations, we consider also the connection to the main grid as a particular case, or the possibility to have a MicroGrid-like structure at the transmission level.

Illustrative Example: ESTHER would benefit a generic Direct Current (DC) MicroGrid composed by several DER (e.g. photovoltaic panels and wind farms), ESS (e.g. lithium-ion batteries and supercapacitors) and a connection to the main Alternate Current (AC) grid. Main control goals would be to ensure power quality (to regulate the DC bus) while extracting the maximum amount of renewable power from the DER, maximising flexibility to Plug&Play situations via the ESS and providing ancillary services to the AC grid.