Traditional research on modal resonance has primarily focused on renewable energy connected to grid systems in terrestrial applications. However

the offshore wind power VSC-HVDC system exhibits significant parameter differences between submarine cables and overhead transmission lines

necessitating clarification of the influence mechanism of submarine cable parameters on system modal resonance. We investigated the interaction between wind turbine grid-side converter (GSC) and VSC-HVDC converters

and examined the impact patterns of submarine cable capacitance and reactance on modal resonance. Moreover

we elucidated the resonant interaction between grid-following controlled GSC and grid-forming controlled VSC-HVDC converters

and establised analytical mapping relationships among submarine cable capacitance/inductance parameters

open-loop modes

and their residues. Critical discoveries indicate that submarine cable capacitance modifies system modal resonance through resonance intensity variation and open-loop mode displacement

thus the oscillation damping is in nonlinear characteristics in VSC-HVDC system

and submarine cable inductance amplifies resonance intensity via residue mechanisms;meanwhile

elevated parameters will intensify the resonance severity and degrade system damping. Time-domain simulations confirm theoretical predictions. Therefore

these distinct mechanisms

contrasting fundamentally with overhead transmission lines behaviors

demand project-specific submarine cable parameter evaluations for effective modal resonance mitigation.