Seamless Integration of Renewable Generation and Plug-in Electric Vehicles into the Electrical Grid

Abstract: An imminent release of plug-in electric vehicles en masse will add substantial load to electrical power grids that are already operating near limits. Coordinated control of vehicle charging, however, can eliminate the need for expensive overhauls of grid infrastructure. Furthermore, the growing penetration of renewable energy sources provides an excellent opportunity to meet the increased electricity demand, but the challenge remains to tackle the variability and intermittency associated with renewable energy. Our research focuses on identifying and analyzing key issues regarding interactions between renewable generation, vehicle charging, and the power grid. In order to address these issues, we are designing control schemes that ensure seamless integration of newer forms of generation and load, while achieving satisfactory grid-level performance in areas such as loss minimization, voltage regulation, generation balancing and valley filling. We show how hysteresis-based control strategies can be utilized to model and control a large number of electrical loads, e.g. thermostatic loads, plug-in electric vehicle chargers. Our study shows that such load aggregations often display rich non-linear dynamic behavior such as period-multiplying bifurcations. We also look at how a synchronized response of vehicle chargers can impact the resiliency of electrical grid. Another interesting issue that we are looking at is optimal control of reactive power output from photovoltaic inverters on a radial distribution feeder, based upon only locally available measurements.