On the role of prosumers owning rooftop solar photovoltaic in reducing the impact on transformer’s aging due to plug-in electric vehicles charging

Abstract

This paper investigates the synergetic effect of rooftop solar photovoltaic (PV) generation owned by residential prosumers (power producers and consumers) on reducing the distribution substation transformer’s aging caused by charging plug-in electric vehicles (PEVs). Unlike previous work considering surveys based on internal combustion engine-based vehicle data (e.g., National Household Travel Survey (NHTS)) are used in estimating the charging demand of PEVs, this work considers actual PEVs charging data based on the 2015 Canadian Plug-in Electric Vehicle Survey (CPEVS). This work further quantifies the resultant aging seen on substation transformers when internal combustion engine-based National Household Travel Survey data as compared to plug-in electric vehicle driving data from the Canadian Plug-in Electric Vehicle Survey. Moreover, a comparison of the substation transformer aging is performed based on varying plug-in electric vehicle charging levels. Results of the scenarios have shown substation transformer loss of life is found to be at least 30% higher when vehicle data is based on plug-in electric vehicle studies versus conventional internal combustion engine vehicles with 0% PV penetration, up to twice as high at 100% PV penetration. Further studies have shown grouped plug-in electric vehicle charging using 3.3kW at 7pm results in twice the transformer aging seen versus plug-in electric vehicles charging beginning upon returning home. Finally, results have shown that the effect of rooftop solar PV owned by residential prosumers was found to reduce substation transformer loss-of-life by 75% in the case of 3.3kW plug-in electric vehicle charging when 100% PV penetration was added to the system. Such reduction is due to a decrease in transformer’s winding hot-spot temperature caused by PV generation despite the non-coincidence between the peak charging demand of plug-in electric vehicles and the peak power generation from rooftop solar photovoltaic.