Robust steady-state initialization of object-oriented advanced thermal power generation system models with application to the case of the SOS-CO ₂ cycle

The energy transition calls for innovative thermal power generation systems with low- or zero-emission and highly flexible operation. Dynamic modelling and simulation are key enabling factors in this field, as controlling such plants is a difficult task for which there is no previous experience and very short design times are expected. The steady-state initialization of such dynamic models is, unfortunately, a critical task involving the solution of large systems of nonlinear equations with iterative methods, which are often prone to failure. In this work, several strategies and methodologies are discussed to robustly achieve steady-state initialization of first-principles equation-based, object-oriented models of advanced thermal power generation systems. These are presented with reference to the Modelica language, but are applicable to any equation-based, object-oriented modelling and simulation environment. The successful application of such strategies and methodologies to the SOS-CO2 advanced power generation system is presented.