Effect of Dispatch Decisions on Small-Signal Stability of Converter-Dominated Power Systems

TL;DR

This paper investigates how dispatch decisions influence the small-signal stability of converter-dominated power systems, highlighting the importance of operating conditions on stability beyond control design.

Contribution

It systematically analyzes the impact of dispatch variables on stability, bridging a gap in existing research focused mainly on control parameters.

Findings

High-voltage capacitive operation limits GFL active power injection.

Inductive operation allows higher active power injections.

GFM converters are generally better suited to supply more active power.

Abstract

Small-signal stability of modern converter-dominated power systems has been the subject of extensive research, particularly from the perspective of device-level control design for grid-forming (GFM) and grid-following (GFL) converters. However, the influence of power flow variables on system stability has received limited attention. Conventional small-signal stability analyses are typically conducted at a specific operating point, emphasizing the selection of control or system design parameters while neglecting the sensitivity of stability characteristics to operating conditions. This paper seeks to bridge this gap by systematically investigating the impact of dispatch decisions on the small-signal stability of converter-based power systems. Our findings are first illustrated on a three-bus system and then validated on the standard IEEE 39-bus test system to demonstrate scalability. Across the test systems, we find that high-voltage capacitive operation of GFL converters limits its active power injection, whereas inductive operation permits higher injections, and it is generally preferable for the GFM converter to supply more active power.