임승택(Seung-Taek Lim) ; 이기연(Ki-Yeon Lee) ; 김동우(Dong-Woo Kim) ; 채동주(Dong-Ju Chae) ; 임대식(Dae-Sik Lim) ; 문재현(Jae-Hyeon Moon)
All over the world, renewable energy had been gotten attention because of the clean energy, low-cost. and so on. The solar generation and energy storage system(ESS) which are based on the DC power system have different characteristics from the general AC system and are close to the end-user of the electric. For these reasons and other positive aspects, the low voltage direct current(LVDC) system, had been studied. The LVDC system has a more complex configuration since the power sources and ground types in IEC 60364. One of them, IT system has the earthing impedance at source and it is more safe than other ground types in aspect fault current passing the human body. So, it has been expected to be used in end-user system. Until now, most of the studies about the LVDC system was related to the power distribution system like load unbalance, fault analysis, efficiency, and so on.
However, the standards about the earthing impedance at the power source for electrical safety did not exist. So, in this paper, the selection of the earthing impedance in IT LVDC system has been studied in an aspect of human electrical safety. For the research, the simulation was performed based on IEC 60364 and IEC 60479 through the Matlab/Simulink and test experiments were conducted. Through the research, it was confirmed the electrical safety according to the source types, voltage level and earthing impedances. Also, it was analyzed the selection of earthing impedance value for the less human effect when the electrical shock occurred.