Drifting pattern and positioning method of oscillation centre in multi‐source oscillation scenes

The variation characteristics of electrical variables and the variation pattern of oscillation centre in multi‐source oscillation scenes are revealed, and a desynchronising centre positioning method is proposed. First, based on the multi‐source oscillation model, the expressions of voltage and current in multi‐source oscillation scenes are derived. And then, according to the definition of oscillation centre, the oscillation centre position function is constructed, as a quantitative description of the position of oscillation centre. On this basis, the impacts of power angle variation trend (oscillation mode), system operation mode variation and unequal emf amplitudes on the oscillation centre are analysed. Simulation results demonstrate that, the oscillation mode is the main factor that affects the drifting pattern of oscillation centre, system operation mode is the main factor that determines the drifting boundary of oscillation centre, and unequal emf amplitudes cause the oscillation centre to deviate towards the side with lower amplitude. Finally, according to the relationship between system emfs when the desynchronising centre appears, the desynchronising centre position function is derived, so that the position of desynchronising centre can be identified. Simulation results on Real Time Digital Simulator of multi‐machine system verify the correctness of the analysis results.