Optimal Charging Strategy of an Electric Vehicle Aggregator in Ancillary Service Market

With the development of vehicle to grid (V2G) technology, electric vehicles (EV) batteries can be a useful resource of flexibility in an ancillary service market. But the simultaneity of charging to fulfill the daily usage energy requirement and providing ancillary service requires power charging strategy coordination and reserve evaluation. In this paper, we develop an optimization model to determine charging power and ancillary reserve sizing at same time. From aggregator's perspective, we analyze the influence under different reserve and signal follow benchmark to examine the maximum possible ability and charging strategy to provide flexibility with best income and least degradation of battery.