An Interconnected Microgrids-Based Transactive Energy System With Multiple Electric Springs

Abstract

Several interconnected microgrids with electric springs (ESs) are proposed to implement a transactive energy system. Providing sufficient operational flexibility for each microgrid to respond to the dispatching commands is essential to implement such an effective transacitve energy system. To achieve this target, the noncritical loads (NCLs) in microgrids are installed with ESs, which are regarded as a type of distributed energy resource (DER) by adjusting their consumed power. In order to determine the size of flexible exchanged power of each interconnected microgrid, a mathematical model is proposed to describe the feasible operating trace of the ES while considering various physical constraints. In this paper, such feasible operating traces are analytically represented with linearized DistFlow equations. It is clearly indicated by the representations that the locations and shapes of the feasible operating traces of ESs are determined by the parameters of NCL, critical loads (CLs), and the connection lines. Based on these results, an optimization model and solving method are developed to determine the optimal operating points for multiple ESs in the microgrid to minimize the total voltage deviations and are verified by the case studies.