Small-Signal Stability Impacts of Load and Network Dynamics on Grid-Forming Inverters

TL;DR

This paper investigates how load and network dynamics influence the small-signal stability of grid-forming inverters and synchronous generators, highlighting the importance of detailed modeling for accurate stability assessment.

Contribution

It provides a comprehensive eigenvalue analysis of inverter-based resources and synchronous machines considering various load and network models, emphasizing their impact on stability regions.

Findings

Network representation significantly affects stability outcomes.

Load models are crucial in stability analysis with inverter resources.

Stability regions vary notably with different load and network models.

Abstract

This paper presents several stability analyses for grid-forming inverters and synchronous generators considering the dynamics of transmission lines and different load models. Load models are usually of secondary importance compared to generation source models, but as the results show, they play a crucial role in stability studies with the introduction of inverter-based resources. Given inverter control time scales, the implications of considering or neglecting electromagnetic transients of the network are very relevant in the stability assessments. In this paper, we perform eigenvalue analyses for inverter-based resources and synchronous machines connected to a load and explore the effects of multiples models under different network representations. We explore maximum loadability of inverter-based resources and synchronous machines, while analyzing the effects of load and network dynamic models on small-signal stability. The results show that the network representation plays a fundamental role in the stability of the system of different load models. The resulting stability regions are significantly different depending on the source and load model considered.