Consensus Control of Electric Vehicle Charging Stations for Providing Performance-Based Frequency Regulation Service

Energy storage plays a significant role in the modern power grid with high penetration of intermittent renewable energy sources. The flexible charging of numerous grid-connected electric vehicles (EVs) is exploited to act as mobile energy storage for power balancing services. This paper proposes a consensus-based control strategy for EV charging stations providing frequency regulation with limited communication among neighbors. The multi-layer control strategy is operated in the agent of each EV charging station. The charging power of EVs are controlled to track the frequency regulation signals depending on the capacity bid submitted to the market within the adjustable range of EV charging power. The algorithm also allocates the frequency regulation power according to the regulation capability of each EV station while satisfying the diverse charging needs of EVs. The effectiveness of the proposed control strategy is investigated on a typical power distribution network with EV charging stations scattered on several feeders. The quality of frequency regulation is assessed by the performance indicators specified by the PJM market (ISO in the United States). A high-performance score that guarantees the entire payment of frequency regulation can be achieved without violating the charging demand of EVs and the power network constraints.