Power system operators deal with the fault current problems seriously, because the large scale fault current not only cause many side effects to the facilities of power system but also lead to severe problems such as blackout. This paper deals with structural analysis and 3-phase fault current stability of the future Seoul metropolitan power system in Korea. Simulation composition and analysis were performed with the 4th Korea Electric & Power Cooperation (KEPCO) power supply planning data using PSS/e. Through the results of simulation, future Seoul metropolitan system has a problem, enormous fault current, which exceeds circuit breaker (CB) rate. This fault current can cause critical damage to power system. To resolve this problem, the algorithm for application of Voltage Sourced Converter Back-to-Back High Voltage Direct Current (VSC BTB HVDC) is being proposed. In the case study, this paper shows most suitable location for solving fault current problem in Seoul metropolitan area.