Modelling Methodology of a Preliminary Electrical Design of an HVAC or HVDC Offshore Wind Farm

Offshore wind energy is a pivotal solution for sustainable electricity generation, contributing to global decarbonization efforts. A key challenge is the efficient transmission of electricity from offshore turbines to onshore grids. Depending on project specifications, high-voltage alternating current (HVAC) or high-voltage direct current (HVDC) may be more suitable, with both serving as essential export system solutions. HVAC is preferred for shorter distances due to its simpler infrastructure and lower initial costs, which increase with the distance due to the reactive power compensation system, while HVDC offers superior efficiency for long-distance, high-capacity projects despite higher upfront investment and complexity. This paper presents a detailed modeling of both transmission solutions using a 540 MW offshore wind farm case study in DIgSILENT PowerFactory software. The selected farm size provides a robust analytical framework and optimizes equipment utilization based on standard cable dimensions. Various transmission distances are analyzed to present technological trends, evaluate the performance of the plant across different scenarios and verify the correctness of the proposed modeling of HVDC and HVAC.