GPS synchronized measurement applications in Japan

Synchronized measurement is necessary for the precise monitoring and control of large-scale power systems, and which is now made possible by the GPS (Global Positioning System). In this paper, the present status of GPS-based synchronized measurement applications to power systems in Japan is surveyed. Especially a GPS-based Data Acquisition System (DAS) for wide area monitoring of power system responses, which has been deployed in the northeast system of Japan, is described. In addition, the research activities related to the GPS-based DAS are presented.