Hierarchical plug-in EV control based on primary frequency response in interconnected smart grid

The penetration level of the renewable energy resources (RER), such as wind power turbines and solar photovoltaic generation, in interconnected power systems has been increased in many countries. A high penetration level of RERs causes some problems to the grid operator, e.g., lack in primary reserve. Due to environmental concern and energy security risk, many countries around the world decided to increase their electric vehicles (EV) in the near future which provides a good chance to use them as a mobile battery energy storage system (BESS). This paper proposes a new scheme to provide necessary primary reserve from electric vehicles by using hierarchical control of each individual vehicle. An EV aggregator based on the vehicle's information such as the required state of charge (SOC) for the next trip, departure time, and initial SOC is proposed. The proposed aggregation scheme determines the primary reserve and contracts it with system operator based on electricity market negotiation. The effectiveness of the proposed scheme is shown by the several simulation studies in the Taiwan power (Tai-power) system to enhance frequency nadir and steady state frequency after a large disturbance.