Hierarchical Energy Management in Islanded Networked Microgrids

Networked microgrids have many advantages for consumers and small energy producers, including higher reliability than non-networked microgrids. However, energy transaction, network interconnection, the intermittent nature of renewable sources, and other problems lead to challenges in the practical implementation of networked microgrids. Despite its favorable use of space, a floating PV system presents challenges that differ from those associated with its land-based counterparts because it is prone to the motion of the surface of the water, resulting in an unpredictable power output. This work presents a hierarchical energy management system (EMS) to address these issues. In level 1 of the EMS, which is for the overall management thereof, a blockchain model is used to manage transactions among microgrids. A grid synchronization algorithm is implemented in level 2 of the EMS, which manages the interconnection of microgrids. Level 2 is activated when an energy transaction between microgrids is needed. An on-line recurrent neural network (RNN)-based controller for an energy storage system (ESS), which is designed specifically to mitigate the problem caused by a floating PV platform, is deployed in level 3 as a local controller. The results of a hardware-in-the-loop (HIL) simulation demonstrate that the EMS can properly coordinate the levels in the hierarchical scheme to interconnect and provide power support between the microgrids. Real-time simulation results show that the ESS controller responds well, proving the viability of the hardware controller. According to these findings, the hierarchical EMS that is proposed in this work can solve the considered problems.