Power System Electromagnetic Transient Stability: an Analysis Based on Convergent Hamiltonian

TL;DR

This paper introduces a novel Hamiltonian-based analysis for electromagnetic transient stability in power systems, addressing limitations of existing models and proving global stability under certain conditions.

Contribution

It develops a convergent Hamiltonian framework using port-Hamiltonian systems and contraction analysis to assess transient stability with electromagnetic dynamics.

Findings

Hamiltonian convergence implies transient stability.

Global stability of synchronized steady state proven for certain systems.

Simulation confirms theoretical results.

Abstract

Transient stability is crucial to the reliable operation of power systems. Existing theories rely on the simplified electromechanical models, substituting the detailed electromagnetic dynamics of inductor and capacitor with their impedance representations. However, this simplification is inadequate for the growing penetration of fast-switching power electronic devices. Attempts to extend the existing theories to include electromagnetic dynamics lead to overly conservative stability conditions. To tackle this problem more directly, we study the condition under which the power source and dissipation in the electromagnetic dynamics tend to balance each other asymptotically. This is equivalent to the convergence of the Hamiltonian (total stored energy) and can be shown to imply transient stability. Using contraction analysis, we prove that this property holds for a large class of time-varying port-Hamiltonian systems with (i) constant damping matrix and (ii) strictly convex Hamiltonian. Then through port-Hamiltonian modeling of the electromagnetic dynamics, we obtain that the synchronized steady state of the power system is globally stable if it exists. This result provides new insights into the reliable operation of power systems. The proposed theory is illustrated in the simulation results of a two-machine system.