Identification of the weakest buses in unbalanced multiphase smart grids with Plug-in Electric Vehicle charging stations

Charging stations will be increasing in popularity as they can promote and support the increasing number of Plug-in Electric Vehicles (PEVs) entering into smart grid to reduce emissions and fuel consumptions. However, the locations, relatively large ratings and unpredictable charging characteristics of these stations can have a significant impact on the performance of smart grid. This paper proposes identification of the weakest buses over 24 hours in order to study and compensate the detrimental impacts of PEV charging stations on voltage profiles and voltage stability of smart grid. Assuming a smart grid communication infrastructure, the positive sequence voltage ranking index V/V_o is utilized in hourly bases to identify the weakest buses in unbalanced multiphase distribution networks without/with PEV charging stations. Simulation results are performed and compared for an unbalanced multiphase 13 node test feeder with different locations of PEV charging stations using DIgSILENT PowerFactory software.