Analysis of Recent Indian Power System Oscillations in North Eastern Region

With the proliferation of phasor measurement units across the Indian power grid, it is now possible to observe and analyze the system-wide dynamic phenomenon. One such dynamic phenomenon is low-frequency oscillation. Oscillation monitoring using PMU data has emerged as a significant application of wide-area stability assessment in power systems. The paper presents an analysis of oscillation events experienced in the North Eastern Region grid. The paper discusses three recent oscillation events of the system. Using archived PMU data of the event, this paper shows the computation of modal analysis using the matrix-pencil method. It highlights the reason behind the vulnerability of the system to oscillations. The analyzed oscillation events in this system indicate that the ac system strength of the system is weak due to the low effective short circuit ratio and low inertia constant. This is because the system is connected to a high dc link rating and has a low short circuit capacity.