Power Oscillation Damping Controllers for Grid-Forming Power Converters in Modern PowerSystems

TL;DR

This paper explores the design and effectiveness of Power Oscillation Damping controllers for Grid-Forming converters in modern power systems, demonstrating their ability to mitigate electromechanical oscillations through eigenvalue analysis and simulations.

Contribution

It introduces novel POD controllers for GFORs using frequency-based input signals and eigenvalue-sensitivity methods, addressing a gap in damping strategies for power electronics-rich grids.

Findings

POD controllers effectively damp oscillations in test systems.

Eigenvalue-sensitivity methods facilitate controller design with limited system info.

Simulations confirm improved stability in large-scale power systems.

Abstract

Inter-area oscillations have been extensively studied in conventional power systems dominated by synchronous machines, as well as methods to mitigate them. Several publications have addressed Power Oscillation Damping (POD) controllers in grid-following voltage source converters (GFOL). However, the performance of POD controllers for Grid-Forming voltage source converters (GFOR) in modern power systems with increased penetration of power electronics requires further investigation. This paper investigates the performance of GFORs and supplementary POD controllers in the damping of electromechanical oscillations in modern power systems. This paper proposes POD controllers in GFORs by supplementary modulation of active- and reactive-power injections of the converter and both simultaneously (POD- P, POD-Q and POD-PQ, respectively). The proposed POD controllers use the frequency imposed by the GFOR as the input signal, which has a simple implementation and it eliminates the need for additional measurements. Eigenvalue-sensitivity methods using a synthetic test system are applied to the design of POD controllers in GFORs, which is useful when limited information of the power system is available. This paper demonstrates the effectiveness of POD controllers in GFOR converters to damp electromechanical oscillations, by small-signal stability analysis and non-linear time-domain simulations in a small test system and in a large-scale power system.