Enabling strategies of electric vehicles for under frequency load shedding

Due to large-scale integration of renewable energy sources into the power grid and the increasing requirements of customers for power quality, under frequency load shedding (UFLS) faces a challenge in ensuring power supply reliability. Large-scale electric vehicles (EVs) as distributed energy storage resources can provide the powerful potential for UFLS to deal with this challenge. In this paper, enabling strategies of EVs are proposed for UFLS to enhance frequency stability and simultaneously reduce power outages, where a hierarchical framework consisting of the control center (CC), EV charging stations (EVCS), and EV terminals (EVT) is developed to implement EVs’ participation in UFLS. In the EVCS, the capacity of EVs is calculated based on EV information from the EVT and uploaded to the CC, and at the same time, the dispatch from the CC is distributed among EVs in the EVCS and sent to the EVT. With the proposed strategies, load shedding can be compensated by the vehicle-to-grid power of EVs to reduce power supply interruptions as much as possible. Simulations on the IEEE 9-bus power system have shown the effectiveness of the proposed approach in reducing power outages and enhancing frequency stability.