Electric Vehicle Impact Assessment on Distribution Network of Phuentsholing

Abstract

This project studies the effects of charging electric vehicles on Phuentsholing's distribution network at various penetration levels. In the DIgSILENT power factory, an existing network was modeled and an analysis was performed for the aggregated domestic load with EV load based on two potential scenarios: low and high levels of uptake of EVs. The charging pattern of an electric vehicle may vary depending on the user's preferences. Two sub-EV charging scenarios (all EV charging at the same time and 50% of EV charging at the same time) were studied to analyze the impact. The scenarios are being formulated in consultation with the distribution engineers. Voltage stability and transformer loading are two significant areas that were assessed. The result indicated a technical violation in the year 2025 under high uptake when all EVs charged at the same time. Further, a worse case was observed in the year 2030, with high uptake, when all EVs charged at the same time. Low voltage issues and transformer overloading were the main causes of network instability. Random quick charger loads on distribution feeders contribute to load unbalance at the feeder level, whereas home chargers cause phase unbalance and voltage dips at the household level. These findings suggest that high EV penetration has a considerable impact on the optimal operation of a distribution system. A mitigation strategy for voltage correction and transformer loading has been presented based on the simulation results