A study on the risk analysis of the existing transformer capacity for the apartment considering potential increase of EVs

Abstract

In an effort to solve the global warming, abnormal climate and environmental pollution, introduction of EVs(Electric Vehicles) has regularized as alternative to ICE(Internal Combustion Engine). Asapenetration rateof EVs gradually expands, it needs the charging infrastructure in an apartment and the increase of electric power demand is expected in the near future. In this paper, two methods are proposed to analyze the TSC(Transformer Spare Capacity) for the charging infrastructure in consideration of utilization rate of existing transformer in the apartment. Throughout the analysis of the existing apartment's case, we analyze the acceptable numbers of EVs are 0.12 per household for the spare capacity considering optimal efficiency operation and 0.1 per household for the spare capacity considering emergency operation. The annual penetration rate of EVs is prospected by 112.5% according to governmentpolicy to supply 0.25 million EVs stock until 2020. Weanalyze that the transformer capacity will reach the limit pointin 8-9 years later, as the acceptable number of EVs is beyond 0.22 per household.