China"s offshore wind power industry is rapidly expanding, shifting from near-shore to far-offshore regions. Submarine cables, crucial for long-distance power transmission between offshore wind farms and onshore substations, often cross active fault zones. Understanding their mechanical responses and failure modes under fault conditions is vital for cross-fault protection. Leveraging a specific offshore wind farm project, this study employs the finite element software ABAQUS to model the interaction between a three-core composite submarine cable and seabed soil. Using displacement control, we simulate fault effects on the cable, focusing on stress-deformation characteristics and failure modes. Results show that fault-induced folding deformation at the fault plane leads to stress concentration. Cable deformation initially follows an "S" shape, progressing to necking with increased displacement. Axial plastic strain and stress near the fault surface yield first, with the yield range expanding. Armored steel wir