Limitations in Energy Management Systems: A Case Study for Resilient Interconnected Microgrids

This paper explores the impact of energy management systems (EMSs) discrepancies that a microgrid may experience due to different time horizon and implementation environment in higher-level EMS as compared to lower level control frameworks. These include time-shifting, magnitude deviation, and averaging effect of the renewables and load demand profiles. We use the resilient microgrid concept as a case study considering that the reliability of such system is crucial, especially during islanding mode. We demonstrate through experiment that the non-ideal effects naturally take place in a microgrid system, resulting a discrepancy between the measured and expected ideal battery state-of-charge. Accordingly, the resiliency of the microgrid may be affected if unplanned load shedding took place in order to not violate the lower limit of the battery state-of-charge. Allowing the battery to discharge at a higher depth may temporarily solve the problem, however, this comes at the expense of a higher rate of battery degradation. Instead, we proposed a power sharing scheme and by interconnecting the microgrids, the resiliency may be improved.