Effect of power sharing control techniques of hybrid energy storage system during fault conditions in DC microgrid

• Published in: Journal of energy storage 2023-11, Vol.72, p.108249, Article 108249
• Main Authors: Shaban, M., Mosa, Magdi A., Ali, A.A., Abdel-Latif, K.M.
• Format: Article
• Language: English
• Subjects: DC microgrid; Fault response; Hybrid energy storage system (HESS); Supercapacitor
• ISSN: 2352-152X; 2352-1538
• DOI: 10.1016/j.est.2023.108249

In terms of efficiency, cost, dependability, and control method simplicity, DC microgrids have recently surpassed AC microgrids. Despite these major benefits, DC microgrids pose protection challenges. The behavior of DC microgrids under fault situations is a crucial study for planning and executing a proper protection scheme. Effect of power sharing control schemes of energy storage systems in DC microgrids protection had largely neglected in previous research work. This paper addresses the behavior of a DC microgrid during fault conditions based on different control techniques adopted for hybrid energy storage systems (HESS) in DC microgrids. The fault response of a DC microgrid is investigated with an actual battery current compensation (ABCC) controller and a reference battery current compensation (RBCC) controller. Furthermore, a simplified equivalent circuit for the voltage balancer in DC microgrids during pole-to-ground faults is evaluated. The DC microgrid consists of a photovoltaic system and a wind energy system as renewable energy sources, as well as HESS composites of battery and supercapacitor as an energy storage system. A half-bridge voltage balancer is used to enable bipolar operation. Because grounding is important for protection, it is implemented through the voltage balancer's midpoint. However, dynamic modelling for a low-voltage DC microgrid has been introduced. MATLAB/Simulink simulation was then created. Renewable energy sources are controlled for maximum power point tracking, whereas HESS is controlled to maintain the DC voltage at a desired value. The study looked at how power sharing controllers have a considerable effect on the fault response of the battery and supercapacitor as well as the DC bus voltage. Following that, the impact of voltage balancer on the fault magnitude and time constant is investigated. Finally, the fault features are extracted, and important recommendations for DC microgrid protection schemes are concluded. •Fault behavior of an isolated DC Microgrid is studied based on two different HESS control schemes.•Different fault types and fault resistance effect are investigated.•The PV, WES, supercapacitor, and battery responses are mainly affected by HESS control scheme.•Simplified Equivalent circuit for voltage balancer during pole-to-ground faults is evaluated.•Fault features in DC Microgrid and recommendations for planning and designing a selective and fast protection scheme are presented.