Submission 144
Evaluation of Grid-Forming Capability and Compliance in Wind Turbines and BESS
WISO25-144
Presented by: Fajril Mardiansah
Introduction
The increasing integration of inverter-based resources (IBRs), such as wind and solar, has introduced new stability challenges in weak-grid environments characterized by low inertia and system strength. Real-world events, including the 4-Hz ERCOT oscillation and the 7-Hz disturbance in Australia’s West Murray Zone, have highlighted vulnerabilities such as voltage oscillations and Phase-Locked Loop (PLL) instability, exacerbated by the displacement of synchronous generators.
Grid-Forming (GFM) converters have emerged as a promising solution, capable of autonomously regulating voltage and frequency to support system stability. In response, regulatory bodies including AEMO, ENTSO-E, and the GPST Consortium have issued guidelines defining the expected behavior of GFM-enabled assets.
This paper, based on the author’s Master’s thesis research, evaluates the performance and compliance of wind turbines (WT) and battery energy storage systems (BESS) operating in grid-forming (GFM) mode. A simulation-based framework is employed to assess their capability to meet evolving grid code requirements and to deliver critical grid-forming services.
Methodology
This study begins by reviewing control strategies that enable grid-forming behavior. Droop control and virtual synchronous machine (VSM) approaches are selected for implementation on both WT and BESS models. The control schemes are initially based on predefined control frame available in DIgSILENT PowerFactory and are subsequently adapted and further developed to reflect the characteristics of each specific asset.
Each model is developed in DIgSILENT PowerFactory, incorporating detailed subsystem dynamics, including pitch control for the wind turbine, DC link voltage regulation, virtual impedance emulation, and current-limiting functionality. The two energy sources—WT and BESS—are interfaced with a common grid-side converter through a shared DC link. Four distinct configurations are established by combining each asset with one of the two grid-forming control strategies described previously.
GFM service definitions are drawn from regulatory specifications, particularly AEMO's 2024 Core Requirements framework, including synchronization capability, voltage source behavior, frequency and voltage regulation, oscillation damping, and fault ride-through with dynamic stability. Compliance is assessed using AEMO’s simulation test suite, with results used to evaluate and compare the performance of all configurations against regulatory benchmarks.
Conclusion
This study presents a simulation-based framework to evaluate the GFM capabilities and regulatory compliance of WT and BESS under two control strategies. By implementing droop and VSM control schemes within a unified modeling environment, the analysis enables a consistent comparison of asset behavior against AEMO's core compliance requirements. The findings are expected to offer insights into the suitability of different GFM configurations for weak-grid applications.