Evaluating Charging Service Reliability for Plug-In EVs From the Distribution Network Aspect

The demands for reducing city pollutant emissions and for reducing fossil fuel consumption have stimulated the development of plug-in electric vehicles (EVs). From the perspective of distribution systems, evaluating the reliability of their charging services for EVs should be essential because reliable charging services would help to encourage the use of EVs and accelerate their deployment. However, the existing literature does not fully explore the fact that the charging processes of EVs can be considered interruptible. Modeling the charging demands as interruptible loads, this paper proposes a systematic charging service reliability evaluation algorithm for distribution systems. First, novel indices specialized for describing the reliability of charging services are proposed. Then, a method for extracting EV integration patterns is proposed. The method features the capability of describing the geographical dispersion of EV integrations, enabling careful inspection of the reliability at each load point in a distribution system. Third, the algorithm considers how charging profiles under uncoordinated and coordinated charging strategies will be affected by electric supply interruptions, as charging strategies would have an effect on the reliability. Finally, a case study is carried out on an existing distribution system in Guizhou Province, China, providing a reference for the planning and operations of distribution systems.