전기차 충전부하에 의한 배전 변압기의 부하율, 핫스팟 온도, 열화, 수명 분석

Abstract

This paper presents the effects of electric vehicle (EV) charging load on aging and life of loss (LOL) of a distribution transformer to provide useful information for enabling high-penetration EV to the utility grid. In order to analyze the effects, the prediction of EV charging demand was performed based on statistical data relating to EVs in Jeju and charging scenarios reflecting regional characteristics of Jeju. The actual data provided by KEPCO were used to the distribution transformer loads. The effects of the distribution transformer including load factor, hot spot temperature, aging, and LOL were analyzed according to EV penetration levels. The aging and LOL of the transformer due to EV charging load were evaluated based on IEEE C57.91-1995 and rose exponentially with the increment of the EV penetration level. It is analyzed that the rate of the transformer life reduction is higher than that of EV penetration increment in the charging pattern which performs the frequent-fast charging with the increase of EV penetration level. The results of this paper suggest that it is essential to examine the capacity, aging, and remaining lifetime of power equipment in distribution system, as well as accurate prediction of EV charging demand corresponding to power demand and supply for the high-penetration EV.