On the Stability of Converter-Dominated Power Systems: Impedance-Based Analysis

摘要

In this paper, sequence impedance-based modelling is applied to a complete microgrid in a generalised form. The example case consists of converters with different grid-feeding and grid-forming controls, a choke, IT-equivalent cable models and a link to the main (external) power network. The derived framework is suitable for a deterministic stability analysis of arbitrarily shaped (even large-scale) power systems. In particular, common converter impedance models are combined with power system models towards a small-signal equivalent nodal admittance matrix in order to analyse controller stability issues. Laboratory experiments covering impedance characteristics as well as stability statements are performed in an effort to verify this approach. The derived procedure is validated based on the close correlation between the analytical model and the experimental results.