A Robustness Measure of Transient Stability under Operational Constraints in Power Systems

TL;DR

This paper proposes a new robustness measure for transient stability in power systems that accounts for operational constraints and uses convex Lyapunov functions to quantify disturbance resilience.

Contribution

It introduces a novel stability criterion considering operational limits and develops convex optimization-based certificates for power system stability.

Findings

The new stability measure effectively quantifies the system's ability to withstand disturbances.

The approach is demonstrated on the IEEE 9 bus system.

Convex Lyapunov functions enable tractable stability certification.

Abstract

The aggressive integration of distributed renewable sources is changing the dynamics of the electric power grid in an unexpected manner. As a result, maintaining conventional performance specifications, such as transient stability, may not be sufficient to ensure its reliable operation in stressed conditions. In this paper, we introduce a novel criteria in transient stability with consideration of operational constraints over frequency deviation and angular separation. In addition, we provide a robustness measure of the region of attraction, which can quantify the ability of the post-fault system to remain synchronized even under disturbances. To assess this new stability specification, we adopt the notion of Input-to-State Stability (ISS) to the context of power systems and introduce a new class of convex Lyapunov functions, which will result in tractable convex-optimization-based stability certificates. As a result, we are able to quantify the level of disturbance a power system can withstand while maintaining its safe operation. We illustrate the introduced stability specification and certificate on the IEEE 9 bus system.