Fault Analysis of Hybrid AC/DC Networks

The increasing integration of voltage source converters (VSCs) in the electric grid has significantly enhanced efficiency and reduced the carbon footprint of power networks. With the growing adoption of VSC, future networks are anticipated to be hybrid AC/DC systems. Analysis of these complex systems is critical for their planning, operation, and design. However, accurately simulating converters during symmetrical fault conditions in large hybrid AC/DC networks remains challenging due to the lack of comprehensive VSC models that account for AC and DC grid interactions. This paper tackles this issue by proposing a phase domain fault analysis method utilizing a quasi-static VSC model interface between the AC and DC grids. Verification studies conducted with PSCAD/EMTDC on the modified IEEE 30-bus network demonstrate the accuracy and effectiveness of the proposed method for symmetrical faults.