Direct current (DC) microgrid control in the presence of electrical vehicle/photovoltaic (EV/PV) systems and hybrid energy storage systems: A Case study of grounding and protection issue

Abstract

Abstract In recent years, the interest in using DC microgrids has greatly increased due to their higher efficiency, less complexity, and greater transmission power compared to AC microgrids. To address challenges in DC microgrids in the presence of electrical vehicles (EVs) and the uncertainty of charging EVs, researchers have used PV/EV combination systems with energy storage systems (ESS). Controlling DC microgrids, including PV/EV/ESS, is crucial to cope with the existing challenges. On the other hand, the research on DC microgrids' protection systems is in the early stages, and there are still many challenges in this field. In addition, differences in control systems can pose different challenges for the protection system. The simulation results in this paper demonstrate that considering the best case (use of unipolar resistance grounding system) the DC bus voltage is improved by 22.3% (based on MAPE% data comparison). In the protection part, the empirical‐mode decomposition (EMD) method and selecting a suitable intrinsic mode functions (IMF) have been used to protect the DC microgrid. The proposed protection method has been tested under pole‐to‐pole and pole‐to‐ground fault conditions. The results show that the proposed method is capable of detecting various fault types in the studied microgrid.

Keywords

• DC microgrid control
• DC microgrid grounded system
• DC microgrid protection
• electric vehicles
• empirical‐mode decomposition (EMD)
• hybrid energy storage systems