Real-time detection of angle instability using synchrophasors and action principle

Abstract

Electric power system is undergoing major technological advances with many new installations of synchrophasors across the North American grid as well in power systems all over the world. Synchrophasors together with modern communication technology facilitate the monitoring of the current state of the power system including the phase angles of the bus voltages at critical buses in a time-synchronized fashion. The algorithms and the controller proposed in this paper detect the fast separation of phase angles among the critical areas automatically by using the synchrophasors, and proceed to mitigate the emerging angle instability by triggering suitable control action. Briefly, the algorithms initiate tripping of critical generators in the accelerating part of the system when necessary, and also initiate load shedding in the decelerating part of the system whenever necessary. The novelty of the algorithms is in the fact that all the decisions are made in real-time purely based on the wide-area synchrophasor measurements without any knowledge of the details of relay actions that may have resulted in the angle instability phenomenon. In the paper, we also explore the application of Hamilton's action principle from classical physics to the real-time analysis of phase angles and frequencies. We postulate that the notion of action or effort used in physics is inherently suited to real-time angle instability detection and illustrate the concept with examples.