Work

Quantitative Transient Stability Assessment and Parameter Design for Grid-Forming Converters Under Asymmetric Faults

Year: 2026

Type: article

Abstract: The transient synchronization stability (TSS) of grid-forming converters (GFMCs) under symmetric faults has been extensively investigated. However, research on asymmetric faults with complex sequence network interactions remains limited, particularly in quantitative TSS assessment and parameter design. To address this issue, a unified transient model for dual-sequence GFM control is first developed by considering the interaction effects. Based on this model, a novel energy function incorporating positive- and negative-sequence potential energy and interaction energy is proposed for quantitative TSS assessment. Then, the effects of different parameters on stability margin are quantitatively evaluated, and the zero-crossing point (ZCP) of the stability margin curve serves as a stability criterion for critical parameter identification, offering theoretical guidance for parameter design. Furthermore, to ensure a positive stability margin and meet the rate of change of frequency (RoCoF) requirement specified by grid codes (GCs), a two-stage coordinated design method via energy function evaluation is proposed, which reveals the tradeoff between TSS and RoCoF constraints. Based on this framework, multiparameter feasible regions are characterized to provide quantitative parameter guidelines for stable operation under asymmetric faults. Finally, experimental results verify the effectiveness of the TSS assessment method and the accuracy of parameter design.

Source: IEEE Transactions on Industrial Electronics

DOI: 10.1109/tie.2026.3722972