Consensus Design for Heterogeneous Battery Energy Storage Systems with Droop Control Considering Geographical Factor

Abstract

This paper proposes a hierarchical control strategy to coordinate battery energy storage devices based on a multi-agent system. The heterogeneous nature of the battery volume is paid much more attention in designing the proportional protocol of the consensus controller. Besides that, a cluster algorithm based on Minimum Spanning Tree (MST) is suggested to represent geographical factor, and on account of that, each Battery Energy Storage System (BESS) is classified into its specific cluster zone. Further, an active leader is assigned to be in charge of information from the external side in every cluster. The consensus algorithm reconciles all clusters in a step-by-step way. Energy level, voltage, frequency and active/reactive power sharing of every BESS can reach consensus by an information exchange within and among clusters respectively. Further, a virtual leader is taken into the active leader role in directing frequency and voltage to the reference values. To verify the consensus algorithm, a modified IEEE 57-bus is employed for time-domain simulations in an islanded mode and all BESSs are working in a discharge model.

Keywords

• battery energy storage system (bess)
• consensus
• geographical factor
• smart grid