Tracking the maximum power transfer and loadability limit from sensitivities-based impedance matching

•Detecting voltage instability.•Maximum transfer point for identifying voltage instability.•Predicting capabilities for taking anticipative control actions.

This paper is concerned with voltage instability detection in power systems. The Impedance Matching (IM) equations are formulated as sensitivities-based equations and practical issues about impedance matching are addressed. This research presents a direct relationship between IM and power injection sensitivities, and proposes the use of a Sensitivity Impedance Matching–(SIM) for detection of instability conditions. SIM may detect the Maximum Transfer Point (MTP) and the Saddle-Node Bifurcation (SNB – the maximum loadability point). Prediction capabilities of SIM based on anticipation parameters and reactive generation limitation in advance are presented. Approximated active, reactive, and also apparent margin indices are proposed. The paper introduces novel theoretical results for designing reliable Voltage Instability Detection (VID) schemes.