Forced Oscillation Source Identification in Power System Using Voltage Oscillation Ratio

Complex and untypical forced oscillation may occur in modern power system due to the wide use of power electronic equipment, and traditional method is difficult to identify these kinds of oscillation. A general identification method is proposed in this paper, which is based on voltage oscillation ratio, according to the fact that the voltage oscillation ratio at the oscillation source is the highest. First extract the fluctuation component and steady-state component of voltage from measured data, then calculate the normalized voltage oscillation ratio, i.e., fluctuating component compared to steady-state component, and finally identify the forced oscillation source which has the largest ratio. This method is suitable for both low-frequency oscillation and sub/super synchronous oscillation, and is immune to the systematic measurement error, and can be used across different voltage levels. The effectiveness of this method is verified by simulation and field cases.