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.