A Research on the Characteristics of Fault Current of DC distribution system and AC distribution systemIn this paper, author describes comparison of fault current characteristics of the direct current (DC) distribution system and the alternating current (AC) distribution system has been conducted. Since the DC distribution system is a capable scheme to be used in future compact distribution systems with high efficiency and reliability, it is estimated that there would be an raise in the installation of DC distribution systems in houses and buildings. For the investigation, DC and AC system to be analyzed are implemented using PSCAD/EMTDC. Simulation results show that the DC distribution system has a number of benefits compared to the existing AC distribution system e.g improved voltage drop problem and quality at the customer. This is because the DC/DC converters of DC distribution system can tone down voltage fluctuations caused by trouble and increase power quality.In recent years environmental problems have become a hot issue in the field of power systems. The countries endorsed to the Kyoto protocol have agreed to reduce the emission of green house gases. This reduction is achievable through the decrease of the various losses associated with production, transport, distribution and consumption of electrical power. In power systems, renewable resources and electrical vehicles are considered as a good alternative. These distributed resources and electrical vehicles generate and utilize DC voltage, therefore these have to be interfaced with DC distribution systems which are more efficient than AC systems when dealing with DC based devices and source. The feasibility of the acceptance of direct current in voltage distribution systems was investigated. In this paper, author describes the fault characteristics of DC distribution system. Comparing with that of the AC system, the fault-ride-through capability of the DC distribution system is verified. In this paper, author analyzed the fault characteristics of the DC distribution system. Possible topologies in existing KEPCO power system are proposed. In simulation analysis part, diverse fault simulations are performed in various points of the test system. After observing simulation results, author concluded that the DC distribution system is stronger than conventional AC Distribution systems.