On Stability and Robustness of Demand Response in V2G Mobile Energy Networks

Demand response (DR) plays a significant role in enhancing the reliability of future smart grids. Electric vehicles (EVs) can be exploited to facilitate DR because their batteries, as a form of flexible energy storage, can be controlled to consume energy from or feed energy back to the grid depending on user needs. However, EVs' mobility is inherently probabilistic, which presents a challenge for system stability particularly. This paper analyzes the stability of DR in which mobile EVs participate. Using the methodology of dynamical complex networks, we present a DR model of vehicle-to-grid mobile energy network in which the EVs generally move across different districts represented as network nodes. EV fleets, therefore, transport energy and energy storage capacity among these nodes in general. A difference equation system is developed to model the DR dynamics of the nodes, which mutually affect each other. A DR algorithm is proposed to control the demand for EV charging and discharging. It is proved that the stability of the algorithm is robust to internode coupling. Numerical results show that incoming EVs that bring new energy and storage into a district can impact the DR stability. Real-world traces of vehicle mobility are used in simulations to illustrate the DR model.