Accommodating more electric vehicles in old residential communities by enabling distributed vehicle-to-grid dispatching and coordinated system operation

Electric vehicles' (EVs') popularity in recent years not only reduces oil demands and gas emissions, but also effectively promotes the deployment of charging infrastructure. However, regarding old residential communities (ORCs), implementing widespread charging facilities may not be a wise choice due to scarce public areas, complex reconstruction, and significant costs. In this context, this paper proposes to utilize vehicle-to-grid (V2G) technology to support the shared DC fast charging for ORCs’ applications. Initially, the underlying reasons for difficult-to-charge issues in ORCs are unveiled and analyzed comprehensively. Then, a hierarchical management framework with operation strategies is designed based on a novel reconstructed charging station architecture. A new power electronic device called smart interlinking unit (SIU) is the critical component in this architecture. Then, an introduced distributed V2G dispatching strategy is to be executed by each local AC charger, considering the extra DC charging load and five typical charging scenarios. This paper also proposes a feeder coordination strategy, taking the efficiency feature of deployed transformers and power converters into account. For the real case studies, the developed V2G dispatching strategy is verified to achieve a prominent 45.7 % EV penetration level. In addition, the efficient problem-solving and lower peak-to-valley difference are to be realized. The feeder coordination strategy is demonstrated to achieve flexible power flow dispatching and overall optimization of operation efficiency effectively.