Early warning of wide-area angular stability problems using synchrophasors

This paper proposes a synchrophasor-based approach for prediction of inter-area angular instability in interconnected power systems and decision support on mitigation actions. The approach is performed in two stages: 1) offline identifying clusters of generators to be monitored by synchrophasors and developing a mitigation-strategy table for potential out-of-step scenarios; 2) online monitoring dynamic grouping of the clusters and estimating a risk index on out of step for each interface where the clusters have either a large angle distance or a significant phase difference about a dominant oscillation mode. The risk index can be used to activate a matched one from the mitigation-strategy table. The approach has been integrated into a synchrophasor-based online situational awareness software package, and is demonstrated on the WECC 179-bus power system in this paper.