Untersuchung der harmonischen Stabilität in Niederspannungsnetzen mittels experimentell ermittelter Komponentenimpedanzen
Simon, Sandor; Monti, Antonello (Thesis advisor); Ulbig, Andreas (Thesis advisor)
1. Auflage. - Aachen : printproduction M. Wolff GmbH (2022)
Book, Dissertation / PhD Thesis
In: Aachener Beiträge zur Energieversorgung 220
Page(s)/Article-Nr.: xvii, 193 Seiten : Illustrationen, Diagramme
Dissertation, RWTH Aachen University, 2022
A new type of stability phenomenon is being observed in low-voltage grids, which can be attributed to the increasing share of regulated components with power electronic components. System failures that have already occurred and a resulting danger to stable grid operation illustrate the unmet need for appropriate investigations and countermeasures. A potential criterion for investigating this so-called harmonic stability is the impedance-based stability criterion (IBSC), for whose application frequency-dependent impedances are required. In the context of low-voltage grids, the experimental measurement of components in the laboratory and the transfer of measurement data to substitute models are beneficial, however knowledge of requirements and preconditions as well as suitable procedures are necessary. Therefore, within the scope of this work, various sub-procedures of a procedure chain based on experimental measurements are examined, further developed and tested for applicability in low-voltage grids. These are the experimental determination of frequency-dependent impedances of heterogeneous low-voltage components, the transfer of the resulting impedances into data-driven, parametric substitute models as well the systemic investigation of the harmonic stability of different low-voltage grids under variation of grid properties and penetration levels. The determined impedances of 24 commercially sold components using the implemented and validated test circuits show a significant heterogeneity and different influencing factors to be considered in low-voltage grids. Various other developments reduce interferences caused by non-linearities and enable measurement under the identified preconditions. Subsequently, a modeling approach and parameterization procedure are presented and experimentally determined impedances are transferred into substitute models. The results of the systemic investigations show that the harmonic stability is guaranteed with a grid connection that is assumed to be passive. However, instability is predicted in an investigation of a grid with a power electronic based grid forming unit. The validation in the laboratory confirms the prediction and illustrates the applicability of the IBSC using experimentally parameterised substitute models.