Coordinated charging of multiple plug-in hybrid electric vehicles in residential distribution grids

Alternative vehicles based on internal combustion engines (ICE), such as the hybrid electric vehicle (HEV), the plug-in hybrid electric vehicle (PHEV) and the fuel-cell electric vehicle (FCEV), are becoming increasingly popular. HEVs are currently commercially available and PHEVs will be the next phase in the evolution of hybrid and electric vehicles. The batteries of the PHEVs are designed to be charged at home, from a standard outlet in the garage, or on a corporate car park. The electrical consumption for charging PHEVs may take up to 5% of the total electrical consumption in Belgium by 2030. These extra electrical loads have an impact on the distribution grid which is analyzed in terms of power losses and voltage deviations. Firstly, the uncoordinated charging is described where the vehicles are charged immediately when they are plugged in or after a fixed start delay. This uncoordinated power consumption on a local scale can lead to grid problems. Therefore coordinated charging is proposed to minimize the power losses and to maximize the main grid load factor. The optimal charge profile of the PHEVs is computed by minimizing the power losses. The exact forecasting of household loads is not possible, so stochastic programming is introduced.