Voltage stability analysis by monitoring voltage - Impedance Ratio applied to Ecuadorian power system

This document presents a new voltage stability index based on signal processing voltage and impedance ratio, both variables measured at a same point of a power system. This index could be used to define a reliable start of load shedding in order to mitigate voltage instability in power system. The analysis was development from a two bus transmission system, and the methodology has been applied to 14 buses - IEEE system and a zone of the Ecuadorian power system.