Impact of Dynamic Operation on Reliability of an Aggregate Battery Energy Storage System

Distributed generators in a microgrid (MG) mostly are renewable energy sources. A system with multiple battery energy storage devices should be used in the MG to improve power supply reliability of these renewable energy sources. This system is defined as an aggregate battery energy storage system (ABESS) that is used to control the source-load power balance such that the MG can operate at high stability and reliability to supply electricity for different customers. To demonstrate significance of the ABESS in the MG, its operation reliability will be analyzed in this paper. A systematic method is proposed to evaluate reliability performance of the ABESS under different dynamic operation cases. Specifically, the paper uses an analytic approach based on Markov models to assess the operation reliability of the whole ABESS. According to dynamic operation cases of a microgrid with the ABESS and photovoltaic (PV) generation systems, the failure rate of the ABESS will be different. Simulation test results are presented and discussed to validate that the operation reliability of the ABESS in the microgrid significantly depends on differently dynamic operating strategies along with the applied voltage stress.