A Survey of Voltage Stability Indicators Based on Local Synchronized Phasor Measurements
Paper in proceeding, 2019

This paper reviews and evaluates the main types of voltage stability indicators (VSIs) based on local measurements and further provides a background to their development. Due to weaknesses during dynamic conditions, the bus VSIs based on Thévenin’s equivalent impedance methods are in general found to be unsuitable for most corrective applications, but may instead be used to estimate local loadability margin to voltage instability. Line VSIs, although requiring some data communication, are in general found to be more robust and may in most cases be used both for predictive and corrective applications. Sensitivitybased VSIs are typically more accurate for detecting voltage instability, but are instead sensitive to measurement noise and are highly nonlinear when the system is close to a voltage collapse, consequently being unsuitable for estimating stability margins. The VSIs based on the local identification of voltage emergency situations (LIVES) concept can take into account the delayed effects from load tap changers, making them suitable for corrective applications and to use in local protection schemes.

instability detection

local measurements

synchronized phasor measurements

voltage instability

emergency control

Voltage stability index


Hannes Hagmar

Chalmers, Electrical Engineering, Electric Power Engineering

Anh Tuan Le

Chalmers, Electrical Engineering, Electric Power Engineering

Ola Carlson

Chalmers, Electrical Engineering, Electric Power Engineering

Robert Eriksson

Swedish national grid

2018 North American Power Symposium (NAPS)


50th North American Power Symposium, NAPS 2018
Fargo, USA,

Advanced visualization of voltage stability limit and system protection based on real-time measurement

Swedish Energy Agency (44358-1), 2016-06-01 -- 2020-12-31.

Swedish national grid, 2016-06-01 -- 2020-12-31.

Driving Forces

Sustainable development

Areas of Advance


Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering



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