Power Quality Ancillary Services Support from Customer-owned Electric Vehicles in Low Voltage Distribution Networks

As electric vehicles (EVs) uptake in the distribution networks continue to increase, it concerns distribution network operators (DNOs) that higher demand due to the charging of the EVs could undermine power quality (PQ) of their network. Of interest are challenges relating to undervoltage and thus the increase in electrical power losses. These challenges are exacerbated if EVs are charged uncoordinated. Therefore, in this paper, an optimized approach is proposed for the charging and discharging of EVs in a typical UK low-voltage distribution network with the goal to provide ancillary services to the DNOs. This is particularly in the context of voltage profile improvement and consequently electrical power loss minimization. The problem was formulated as a quadratic optimization task and solved using MATLAB. Results demonstrate that while uncoordinated charging could pose a challenge to the system operation, smart charge and discharge strategy of EVs can indeed offer power quality ancillary services (voltage profile improvement) to the system operator.