Synchrophasor based early-warning voltage instability index

This paper presents an early-warning voltage instability index based on synchrophasor data. The proposed voltage instability index observes the rate of V-Q sensitivity for assessing voltage instability and impending voltage collapse. The proposed index evaluates system voltage dynamics and indicates voltage instability with early-warning capability. This paper also shows a practical implementation of the proposed voltage instability index using measured synchrophasor data to assess situations of voltage instability and voltage collapse. The proposed index is investigated and examined by simulation study of a two-area smart grid test system using DIgSILENT Powerfactory software. The simulation results reveal performance and effectiveness of the simple-but-effective early-warning voltage instability indicator.