Multi-functional energy storage system for supporting solar PV plants and host power distribution system

Abstract

Energy storage systems (ESS) will play a critical role in the ongoing development of the future electrical grid, especially as penetration of renewable energy generation increases. Since the costs of ESS are still high, it is imperative to research diverse control modes of ESS so as to use them in an effective manner, thereby offsetting their high costs. ESS technologies can diminish curtailment of renewable generators and provide much needed storage capabilities for supporting the grid, such as providing voltage regulation, relieving congestion, and improving power quality. This study develops six control modes for a battery ESS (BESS), namely, Current Limiting, Power Limiting, Load Leveling, Voltage Regulation, Power Factor Correction, and Simultaneous Real and Reactive Power Supply. The control modes are verified by simulation using a realistic utility 2.8-MW/5.6-MWh BESS and three solar PV plants connected to a power distribution grid. The study results demonstrate that the BESS functions properly in all the control modes. It can be used in all four quadrants of real and reactive power, i.e., it can provide any combination of real and reactive power amount within its rating for supporting the solar PV farms and the grid. The control modes enable effective operation of the BESS, which is a new tool to solve power system critical operational issues, thereby helping ensure the grid resilient, efficient, and reliable operation.