Impact of EV Charger Load on Distribution Network Capacity: A Case Study in Toronto

This paper presents a study of the impact of the electric vehicle (EV) charger load on the capacity of distribution feeders and transformers of an urban utility. A residential neighborhood of the city of Toronto, Canada, is selected to perform the study based on survey results that showed a high tendency for EV adoption. The two most loaded distribution transformers of such a neighborhood are studied along with their cable feeders via steady-state simulations in CYME software. A worst case scenario of full EV penetration is studied, where all chargers are connected to the system simultaneously at the peak summer or winter load. The effect of increasing the rate of EV adoption on the performance of distribution networks is examined with correlation to the ambient temperature. Finally, the impact of increasing the charger size on system performance is explored. The results send a few warning signals of potential equipment overload to utility companies under certain system loading and EV charging levels as EV use grows, impacting utility future planning and operation. This will assist utilities in taking appropriate measures with respect to operating the existing system and also planning for the future.