Monitoring System for Japan Western 60Hz Power System Based on Multiple Synchronized Phasor Measurements

Japan Western 60Hz System consists of six major electric power companies. Due to its longitudinal structure there are some significant oscillation modes represented by long term oscillation among whole system. Independent load frequency control based on Tie-Line Bias control (TBC) is adopted in each company. Also some independent power producers are participating in the power generation business. In the circumstances the system may show some interesting dynamics. So far, some oscillative characteristics have been measured in own area or in the interconnected tie lines. However, there was little observation as a whole power system. In this paper the authors present an global monitoring system of power system dynamics by using the synchronized phasor measurement technique, which are located in some universities in the 60Hz power system. Phasor measurements are synchronized based on the global positioning system (GPS) and measured data are transmitted via Internet. Some oscillative features and variation of phasor in a day, a week or a year are analyzed using the acquired data.