Capacity Configuration of Energy Storage Systems for Echelon Utilization Based on Accelerated Life Test in Microgrids

Retired power battery construction energy storage systems (ESSs) for echelon utilization can not only extend the remaining capacity value of the battery, and decrease environmental pollution, but also reduce the initial cost of energy storage systems. In this paper, an ESS constructed of retired power batteries for echelon utilization in microgrids (MGs) is considered. Firstly, considering the influence of different discharge depths on the battery life cycle, the correlation equation between the state of charge (SOC) and the state of health (SOH) is established. Secondly, the accelerated life test method, based on the inverse power law coefficient equation, is proposed, and it is used to evaluate the reliability of the ESS. Finally, according to the SOC characteristics, the dynamic security margin of the ESS is established. The life cycle cost, supply-demand balance and ESS balanced control are comprehensively considered, and the location and capacity of energy storage in MGs are determined. It is simulated using the IEEE-RTS 24 node system; the results show that the investment cost of the ESS is reduced and the operational life is prolonged.