A virtual power plant for coordinating batteries and EVs of distributed zero-energy houses considering the distribution system constraints

Due to the increasing installation of residential electric vehicle (EV) chargers to benefit from the low tariff rates during off-peak hours, the simultaneous charging of a large number of EVs affects the voltage profile and the transformer loading of a radial distribution network. Hence, this paper presents a virtual power plant (VPP) configuration that aggregates the data of dispersed residential batteries and EVs and coordinates their charging and discharging to regulate bus voltages and reduce transformer loading levels. This can be achieved by firstly ensuring that the batteries are completely charged during the daytime utilizing the available solar power and the grid power. After that, the residential EVs will be charged at night by using the grid and batteries. To ensure charging fairness for the customers, the VPP gives the charging priority to the EVs with lower states of charge (SOCs). The efficacy of the proposed VPP is tested on the radial IEEE 33 bus distribution system, including forty-five models of distributed zero-energy houses (ZEHs). The simulation results revealed that the VPP performs within the bus voltage and the transformer loading limits. Moreover, the VPP reduced the hot spots on transformers and transmission lines due to the possible large instantaneous power losses on them.