WAMS ? Mitigating angular instability in large interconnected power systems

This paper explains the need of controller to detect the fast separation of phase angles among the critical areas automatically using synchrophasors and proceed to mitigate the instability by suitable switching action. Power systems are large interconnected nonlinear systems where system wide instabilities or collapses do occur over time. In that case, the system breaks up into many islands resulting in large loss of loads and generations and a potential blackout scenario. Phasor Measurement Unit (PMU) technology provides phasor information (both magnitude and phase angle) in real time. The advantage of referring phase angle to a global reference time is helpful in capturing the wide area snap shot of the power system. Accordingly, operator actions together with automatic control actions are designed to prevent or minimize the damage caused by such outages. Effective utilization of this technology is very useful in mitigating blackouts and learning the real time behavior of the power system.