The reactive power, unlike frequency, has local characteristics and it has relied on the manual operation in a local reactive power control station so far. Since coordination or integrated control was possible due to the recent advances in computers and communication networks, the hierarchical voltage control system, consisting of primary, secondary, and tertiary, has been already applied to the real-life situations of several developed countries in Europe. Recently, the Korea power system has been operated more closely to stability limits because of rapid growth in load-demand as seen in Europe. For this reasons, KEPCO recognized the need of the voltage control system and developed the voltage control system. In this paper, we developed intelligent voltage control system for domestic system using numerical algorithm based on the sensitivity matrix and expert system, and dynamic response characteristics of the developed system investigated as a preliminary step for interfacing RTDS(Real Time Digital Simulator). In addition, the developed system performance was verified.