When multiple grid-forming and grid-following converters operate within an offshore energy system (OES)

dynamic interactions among them can lead to poorly damped oscillations and potential instability. This paper proposes a computationally efficient reduced-order state-space modelling framework for small-signal stability and parametric sensitivity analysis of large-scale OESs. The approach replaces complex full-order analytical modelling with a practical MATLAB/Simulink-based linearisation procedure

enabling tractable stability assessment of systems comprising multiple wind plants

electrolysers

HVDC links and network components. The reduced-order model preserves the dominant dynamics while significantly decreasing the number of states

thereby improving computational efficiency for eigenvalue and sensitivity analyses. Using the linearised model

the influence of key control parameters is systematically quantified to provide explicit guidance for controller tuning and damping improvement. The accuracy of the proposed model is validated through comparison with detailed electromagnetic transient (EMT) simulations in PSCAD/EMTDC

demonstrating close agreement in dynamic responses and stability characteristics.