Distributed coordination of energy-storage capacities in virtual microgrids

An approach for distributed coordinated scheduling of storage capacities is presented. When storage capacities are connected in the same grid, behind a common transformer substation, mutual charging and discharging can occur, which can be prevented by the herein introduced coordination method. When cooperation is incorported, storage capacities can be operated as a virtual microgrid. The cooperation between nodes is based on the formulation of a simple objective function for coordination. The cooperation objective is then combined with each node's local objective, which is the increase of self consumption, such that load is released off the the grid. A qualitative reflection on the practical use of three distributed algorithms, to solve the formulated optimisation problem is provided. The Jacobi algorithm is qualified to be preferable for large-scale networks with a great number of nodes, and the Gauss-Seidel algorithm is preferable when less nodes cooperate. To illustrate the concept and show the effect of coordination for prevention of mutual charging/discharging of storage capacities in a VMG, two comparative case-study scenario are presented.