Fleet of electric vehicles for frequency support in Smart Grid using 2-layer hierarchical control mechanism

Penetration of electric vehicles (EVs) in the market, have gained significant momentum in the last couple of years. EVs not only deliver efficient transportation facilities, but also reduce the carbon footprints in the environment. In addition to this, EVs have the intrinsic ability to support the grid during peak and off-peak hours, which can be efficiently utilized to provide instantaneous frequency support. Motivated from these facts, this paper primarily aims to exploit the distributed energy from EVs efficiently, for providing coordinated grid support during frequency deviations. This has been achieved by using a 2-layer hierarchical control mechanism, comprising of physical and control layers. The physical layer constitutes of different entities such as-charging stations, aggregators and a substation, while the control layer is composed of two controllers, i.e., central and local. These controllers employ droop characteristics for load redistribution at different levels. Furthermore, the local controllers regulate the charging and discharging rates of participating EVs in order to support simultaneous and bi-directional energy exchanges. The publically available PJM data has been used to validate the results obtained, which clearly indicate the efficacy of the proposed scheme in the real-time scenario.