A Study on the Protection Coordination of Korean Distribution System using IEC Curve

In this paper, we investigate the protective coordination using International Electrotechnical Commission (IEC) curve. In the conventional protective system of the distribution system in Korea, modified IEC curves and curves developed by Korea Electric Power Research Institute (KEPRI) have been used. The use of such a mixed curves causes the protective coordination system to malfunction. It is argued that this malfunction must be corrected for the protective coordination system of the domestic distribution system, and the only one unified international standard IEC curve should be used for this. Therefore, in this paper, only the very inverse curves of IEC curves are used to coordinate easily with each other and set up to comply with domestic regulations. A protective coordination simulation which simplified the protective system of the domestic power system is conducted through Electrical Transient Analyzer Program (ETAP) and MATLAB. The simulation results show that each protective device follows the protective coordination rules within the prescribed rules.