Generalized AC/DC Power Flow Methodology

The integration of high-voltage DC (HVDC) systems alongside traditional AC grids presents both challenges and opportunities for modern power networks. Central to analyzing these systems is the power flow methodology. However, existing approaches for hybrid AC/DC grids often fall short, particularly in accurately modeling the diverse control possibilities offered by converters and efficiently solving the complete system. This paper introduces a unified Generalized AC/DC Power Flow method that addresses these limitations by incorporating key features: rich converter modeling possibilities, controls integration, and most notably a unified approach that handles AC and DC grids as a single system and achieves quadratic convergence. In addition, this methodology solves the convergence issues typically encountered in other approaches. We achieve this by offering a fundamental rethinking of the role of bus types in the power flow formulation. The proposed method is validated using large systems, including the Polish transmission network (which is an openly-available 3120-bus system) and other modified IEEE test systems, demonstrating its robustness and scalability. The algorithm outperforms the benchmark by converging to the solution between 70.21% to 91.36% faster depending on the test case, and has also been fully integrated into VeraGrid, a popular open-source tool for power systems analysis.