Observation of power system oscillation characteristics by using measurement data obtained from demand side outlets

In Japan western 60 Hz system, it is generally known that its longitudinal structure produces various system oscillations, such as long term oscillation, local generator oscillation and oscillation caused by frequency control among systems. However, little is known about the wide-area phenomenon in systems. The purpose of this study is to establish the analysis method used actual measurements and to clarify the oscillations in the power systems. Authors placed PMLJ (Phaser Measurement Unit) connected to 100 V outlets in some Universities in the 60 Hz power system. PMU is synchronized based on the global positioning system (GPS) and measured data are transmitted via Internet. In present, the technique for clarifying the oscillation in the power systems is being investigated. This paper describes some results to evaluate the power system oscillation characteristics by PMU.