Voltage support by optimal integration of plug-in hybrid electric vehicles to a residential grid

This paper provides a linear approach to compute the voltages at any node on a residential grid based on the house instantaneous load and the presence of charging Plug-In Hybrid Electric Vehicles (PHEV) on the grid (and the corresponding instantaneous consumption or injection). Based on this linear operation, the paper provides a detailed Linear Programming (LP) formulation of the problem of charging the PHEVs while providing a voltage support service to the grid. The approach gives optimal charging schedules for each PHEV in a centralized way, looking for benefit on the customer´s perspective. Multiple evaluation cases are included in order to test the ability of the approach to maintain voltages within safety limits and provide optimal consumption/injection policies. An additional case is included to prove the potential of the PHEVs to solve existing voltage technical issues on a residential grid. The formulation is proposed as a benchmark to identify possible benefits and elements that could be useful for more realistic applications.