Distributional two-level synergetic unit commitment considering three scheduling states

Abstract

The high penetration of distributed energy resources (DERs) (i.e. solar energy, wind power, photovoltaic and energy storage system) are integrated into the transmission grid (TG) and the active distribution networks (ADNs) in a centralized or decentralized manner or distributed manner, which significantly impose crucial challenges on the frequency regulation of power system. To make full use of the frequency regulation effect in dispatch and control, and considering the topology interlinked and the information sharing between TG+ADNs, in this paper, a distributional TG+ADNs two-level synergetic unit commitment (TLS-UC) considering three scheduling states is proposed. To explore the synergetic capacity of the TG+ADNs accommodating uncertainties of load and DERs, three scheduling states including the automatic synergetic state (i.e. primary frequency regulation (PFR)), the coordinated synergetic state (i.e. secondary frequency regulation (SFR)) and the controlled synergetic state (i.e. economic dispatch (ED)) of TG are defined and implemented to deal with uncertainties through the interconnection of the tie-line between TG+ADNs. A decentralized and parallel analytical target cascading (ATC) algorithm is employed to solve the proposed TLS-UC model. A modified 6-bus TG system with 2 ADNs (T6D2) and IEEE 118-bus TG system with 10 ADNs (T118D10) are used to test the proposed TLS-UC model. Test results illustrate that the proposed method is effective and efficient, and it can enhance the synergic capacity of power system to keep source power balance under uncertainties.