Out-of-Step Detection Based On an Improved Line Potential Energy Criterion

TL;DR

This paper improves the line potential energy criterion for generator instability detection by addressing its limitations, extending its applicability, and proposing strategies for early detection in practical power systems.

Contribution

The study modifies the theoretical derivation of the line potential energy criterion to overcome idealized assumptions and enhances its effectiveness for online generator stability monitoring.

Findings

Extended the criterion's applicability to more realistic load conditions

Proposed two strategies for early instability detection

Provided theoretical support for online implementation

Abstract

The line potential energy in the cutset is used as the criterion for monitoring the generator instability, but the criterion has the following two limitations due to narrowly defined conditions. The assumption of an ideal constant power load is difficult to satisfy, and the condition of the critical cutset is too narrow. The limitations are addressed by analyzing the relationship between the power of the load elements and the power of the cutset based on the two-machine equivalent. Modifications of the theoretical derivation steps of this criterion are presented to extend the applications of the criterion and provide theoretical support for its online use. Two simple strategies are proposed to ensure early detection of the generator instability.