Page - 51 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 8. EffectsofEVs Vehiclesmayserve thepurposeof transportation,but theyaffecta lotofotherareas. Therefore, theshift in thevehicleworldcreatedbyEVs impacts theenvironment, theeconomy,andbeingelectric, theelectrical systemstoagreatextent. EVsaregainingpopularitybecauseof thebenefits theyprovide inall theseareas,butwith them, therecomesomeproblemsaswell. Figure61 illustrates the impacts ofEVsonthepowergrid,environmentandeconomy. Figure61.Ashort listof the impactsofEVsonthepowergrid,environmentandeconomy. 8.1. Impacton thePowerGrid 8.1.1.Negative Impacts EVsareconsideredtobehighpower loads [114]andtheyaffect thepowerdistributionsystem directly; thedistributiontransformers, cablesandfusesareaffectedby it themost [115,116].ANissan Leafwitha24kWhbatterypackcanconsumepowersimilar toasingleEuropeanhousehold.A3.3kW charger ina220V,15Asystemcanraise thecurrentdemandby17%to25%[117]. Thesituationgets quitealarmingif charging isdoneduringpeakhours, leadingtooverloadonthesystem,damageof thesystemequipment, trippingofprotectionrelays,andsubsequently,an increase in the infrastructure cost [117]. Chargingwithout any concern to the timeofdrawingpower from thegrid is denoted asuncoordinatedcharging,uncontrolledchargingordumbcharging[117,118]. Thiscanleadtothe additionofEVload inpeakhourswhichcancause loadunbalance, shortageofenergy, instability, and decrease inreliabilityanddegradationofpowerquality [116,119]. Incaseof themodifiedIEEE23kV distributionsystem,penetrationofEVscandeviatevoltagebelowthe0.9p.u. levelup to0.83p.u., with increasedpower lossesandgenerationcost [118]. Level 1 charging froman110Voutletdoes notaffect thepowersystemmuch,butproblemsariseas thechargingvoltage increases.Addingan EVfor fast chargingcanbeequivalent toaddingseveralhouseholds to thegrid. Thegrid is likely tobe capable ofwithstanding it, butdistributionnetworks aredesignedwith specificnumbers of householdskept intomind, suddenadditionofsuchhuge loadscanoften leadtoproblems.Reducing 51