Fault analysis for DC Bus-integrated energy storage system, electric vehicle supply equipment, and photo voltaic systems

Reliable access to cost-effective electricity is the backbone of the U.S. economy, and energy storage is an integral element of the power system with high penetration of Distributed energy resources (DERs). Investment in energy storage is essential for keeping pace with the increasing demands for electricity arising from continued growth in U.S. productivity, continued expansion of national cultural imperatives (e.g., emergence of the distributed grid and electric vehicles), and the projected increase in DERs. This research is on the forefront of this transition with fault analysis execute for a real system to be implemented in New York City at a Utility substation. The project seeks to pair a grid-connected battery energy storage system (BESS), solar photovoltaic (PV) system, and an electric vehicle charging system (EVCS) on a common DC bus. A transient model has been developed and different fault scenarios (i.e., high-impedance and low-impedance faults) have been simulated, at various points of the system for several durations. The objective of this study is to determine the requirements for electrical protection equipment, i.e., DC Circuit Breakers (DCCBs) in terms of capacity and fault clearing time that can ensure stable operation of the DC bus system while meeting the utility and IEEE requirements for system stability. The results showed that fast-response DCCBs is a key element for the system. Solid-State DC breakers with ultra-high speed must be deployed for prompt detection/isolation of faults. Actual ratings of converters and allied equipment need to be considered before the finalization of ratings and specification of protection equipment.