On the Input-Output Monotonicity of Voltage Dynamics of Power System with Grid-Forming Converters

TL;DR

This paper demonstrates that power system voltage dynamics with multiple grid-forming converters often exhibit input-output monotonicity, providing insights into system behavior and aiding stability analysis.

Contribution

The study introduces a systematic method to analyze the derivatives and sign patterns of voltage dynamics, revealing the conditions for input-output monotonicity in systems with GFM converters.

Findings

Voltage dynamics often exhibit input-output monotonicity.

The derivative computation method offers structural insights.

Simulation validates theoretical predictions.

Abstract

Integration of renewable resources is profoundly reshaping the dynamics of modern power systems. This study shows that the voltage dynamics of power systems with multiple grid-forming (GFM) converters often enjoys a desirable property called input-output monotonicity. A systematic approach for computing the derivatives of the voltage subsystem is presented first, which provides insight into the structural characteristics of these models. Next, the sign pattern of the trajectory Jacobian matrix associated with the voltage subsystem is analyzed and revealed. The analysis indicates that the voltage dynamics of power systems often exhibits the so-called input-output monotonicity property. The theoretical results are then validated through several simulation examples, underscoring their practical implications.