Counterexample to Equivalent Nodal Analysis for Voltage Stability Assessment

TL;DR

This paper challenges the accuracy of the L-index and an improved index for voltage stability assessment, demonstrating through a counterexample that the proposed stability condition is incorrect.

Contribution

It provides a counterexample showing that the previously claimed exact stability condition based on system equivalencing is invalid.

Findings

The L-index is inaccurate for voltage instability detection.

The proposed stability condition is incorrect as demonstrated by a two-bus system counterexample.

Counterexample invalidates previous claims of an exact stability criterion.

Abstract

Existing literature claims that the L-index for voltage instability detection is inaccurate and proposes an improved index quantifying voltage stability through system equivalencing. The proposed stability condition is claimed to be exact in determining voltage instability.We show the condition is incorrect through simple arguments accompanied by demonstration on a two-bus system counterexample.