Impact Analysis of Electric Vehicles on Distribution System (A Case Study on Patan Feeder, Pulchowk DCS)

Abstract

With the vision of reducing the dependency on petroleum products for transportation and maximize the consumption of electricity generated, the Government of Nepal GoN and NEA has set up plans to encourage the use of Electric Vehicles (EVs). EVs not only reduces the consumption of petroleum products for transportation but also helps in pollution free transportation. In order to compete with petroleum-based transportation, NEA has plans to set up EV charging station as many as possible. The increased number of charging station will increase EVs in the Distribution System. In this study of Impact Analysis of Electric Vehicles EVs on Distribution System, the effect of different penetration level of EV battery charging on Distribution System is analyzed. This research presents a methodology for modelling and analyzing load flow and harmonic analysis in a distribution system due to EVs. This study focuses on voltage deviation, line loss and total harmonic distortion caused due to different penetration level of EVs in the Distribution System. Due to ever increasing use of electric vehicle in the world, an electric utility must be able to meet the both energy demand and peak demand caused by charging of EV’s. Not only the peak demand and energy demand fulfillment, a utility must be able to maintain its THD within prescribed limit. So, in order to make the system healthy, the supply side of EV battery charging circuit must be harmonic free. For the study purpose ETAP software is used and impacts on Patan feeder, Pulchowk DCS of NEA are studied on different cases of load periods and with and without EV penetration as well. As the selected feeder comprises of two charging stations and transformers capacity of 200 kVA and 1000 kVA, impacts are studied based on the charging stations operating individually and simultaneously. Voltage Deviation and Line Loss are found to be increased at peak demand period with the increased EV penetration while THD is found to be increased at off peak period with the increased EV penetration. This is because at off peak period, with the increased EV penetration, the EV load is very high and the use of converters becomes high. Voltage Deviation and Line Loss goes on increasing with the increase in power demand even without EV Penetration. Maximum Voltage Deviation is 4.82% at Labim Bus at peak demand period. Line Loss is maximum at peak demand period of 102 kW. Maximum Voltage Deviation is 5.83% at Labim Bus at 100% EV Penetration during peak period and Line loss 121 kW, which is also highest at the same period and same penetration level when both Sajha and Labim Mall Charging station are operating simultaneously.