Load power smoothing control of distribution network including photovoltaic generation with energy storage from electric vehicles

The penetration of the distributed photovoltaic (PV) has caused inevitable power fluctuations in the distribution network. The traditional generators can hardly respond to the rapid load power fluctuations. With the development of the vehicle-to-grid (V2G) technology, the aggregated electric vehicles (EVs) are able to operate as an energy storage system (ESS) to follow the rapid power fluctuations. Thus it is critical to obtain the maximum energy storage capacity of aggregated EVs and propose an effective smoothing control strategy for the coordinated power control of EVs when responding to the power fluctuations. To solve this problem, based on the maximum operation area of an individual EV considering the travelling behaviors, the response parameters of the aggregated EVs, such as the total exchanged power, the response capacity of the total exchanged power, the energy storage capacity and the SOC value, are defined to describe the energy storage characteristics of the aggregated EVs. Then a load power smoothing control strategy is proposed to smooth the load power fluctuations of the distribution network. The required power change is determined by evaluating the power fluctuation rate of the load, and then the required power change is allocated to each EV based on a developed SOC-adaptive method. The simulation results show that the aggregated EVs are able to decrease power fluctuation rate of the load and the travelling comfort levels of EV users are guaranteed with the SOC-adaptive method.