Toward Simulation-free Estimation of Critical Clearing Time

TL;DR

This paper proposes a novel, simulation-free method for estimating the critical clearing time in power systems by bounding fault-on dynamics and using convex optimization, significantly reducing computational effort in contingency screening.

Contribution

It introduces a new framework that eliminates the need for fault-on dynamics simulations in transient stability assessment, leveraging Lyapunov functions and convex optimization.

Findings

Successfully validated on IEEE test cases.

Achieves lower bounds of CCT without time-domain simulations.

Reduces computational resources for contingency screening.

Abstract

Contingency screening for transient stability of large-scale, strongly nonlinear, interconnected power systems is one of the most computationally challenging parts of Dynamic Security Assessment and requires huge resources to perform time-domain simulations-based assessment. To reduce computational cost of time-domain simulations, direct energy methods have been extensively developed. However, these methods, as well as other existing methods, still rely on time-consuming numerical integration of the fault-on dynamics. This task is computationally hard, since possibly thousands of contingencies need to be scanned and thousands of accompanied fault-on dynamics simulations need to be performed and stored on a regular basis. In this paper, we introduce a novel framework to eliminate the need for fault-on dynamics simulations in contingency screening. This simulation-free framework is based on bounding the fault-on dynamics and extending the recently introduced Lyapunov Function Family approach for transient stability analysis of structure-preserving model. In turn, a lower bound of the critical clearing time (CCT) is obtained by solving convex optimization problems without relying on any time-domain simulations. A comprehensive analysis is carried out to validate this novel technique on a number of IEEE test cases.