Optimal scheduling of PHEVs and D-BESSs in the presence of DGs in a distribution system

Abstract

Optimisation of cost and load flattening for a distribution network is attempted in this work. The objective function is described in terms of energy cost, CO2 emissions, real power losses, and load flattening. The solution is envisaged in terms of hourly scheduling of distributed generations (DGs), distributed battery energy storage systems (D-BESSs), and plug-in hybrid electric vehicles (PHEVs). An investigation in the reformulation of the cost of energy is carried out to eliminate the solutions involving excessive charging and discharging of BESSs/D-BESSs and PHEVs. It is demonstrated that simultaneous optimisation of cost, CO2 emissions, real power losses, and load flattening cannot be effectively solved as a weighted sum objective function. An e-constraint method is applied to obtain the optimal scheduling to achieve cost optimisation, load flattening, and minimisation of CO2 emissions from the utility point of view. A case of decentralised multi-agent optimisation problem is also formulated and compared. It is observed that the combination of the scheduling of DGs, BESSs/D-BESSs, gridto-vehicle/vehicle-to-grid can successfully be used to significantly reduce the system peak demand along with system cost, losses and CO2 emissions. © The Institution of Engineering and Technology 2019.