Real-time Voltage Instability Indicator (RVII): Enhancements and case studies

Real-time Voltage Instability Indicator (RVII) belongs to the class of measurement based voltage stability indicators that are real-time, model-free, and run at synchrophasor rates. These features allow RVII to react instantly to changes in the system, detect imminent instability, and serve as a defense mechanism against critical conditions. The foundation of RVII is based on the principles of maximum power transfer and Thevenin equivalents, which make it adaptive and scalable for use in advanced features including extrapolation, prediction, and model based contingency analysis initiation. This paper describes improvements to these advanced features, with practical use cases presented using a combination of results from offline and online testing through integration at Pacific Gas and Electric Proof of Concept facility.