Stochastic Battery SOC Model of EV Community for V2G Operations Using CTA-2045 Standards

An electric vehicle (EV) battery has large energy storage capacity in the context of residential total usage, and the potential to provide large energy reserves for Home energy Management (HEM) systems. In an electric distribution system, groups of EVs could provide vehicle-to-grid (V2G) service in response to control signals and enable virtual power plant (VPP) operation of the car batteries. The CTA-2045 standards were considered for integration of the EV controls into the HEM system for maximal interoperability with other appliances, such as residential battery, electric water heater, and heating, ventilation, and air conditioning (HVAC) system. The power distribution system under study was modeled based on a modified IEEE 123-bus feeder test case in OpenDSS software. The availability and state of charge (SOC) of EVs were calculated based on the national household travel survey (NHTS) data following a new procedure to create synthetic communities following experimental probability density functions (PDFs). Example case studies for long and short term V2G services were completed in this paper from the perspective of the distribution system. The power flow for the distribution system, the voltages on the buses, as well as the SOCs and available energies of the EVs were calculated following the control signals on an example day.