Oversea distribution automation system based on Japanese experience

Outage time in Japan is the shortest in the world because Japanese power utilities have applied distribution automation system (DAS) in the whole area. Toshiba developed and supplied DAS using a computer from 20 years ago and have been supplying DAS in Japan and in overseas countries. Therefor, we introduce DAS for overseas countries based on our long-term experience. Major points are as follows. DAS using only local equipment (vacuum switch (VS)/fault detecting relay (FDR)): (1) comparison between recloser and VS/FDR; and (2) recommendation system combined recloser and VS/FDR. DAS using computer: (1) display of distribution network with mapping system; (2) automatic power supply; and (3) underground DAS using automatic ring main unit. Communication system for DAS: (1) comparison among radio, twisted pair cable and optical fiber; and (2) optical fiber communication system. We also introduce DAS in future with new technology such as TCP/IP network.