Methodological work on HVDC modelling in the French electrical network using the Antares simulator

This master thesis investigates the modelling of High Voltage Direct Current (HVDC) lines within the French high-voltage transmission network using the Antares simulation tool. As the energy system undergoes significant transformations driven by increasing electricity demand and the integration of renewable generation, particularly offshore wind, the need for accurate representation of network reinforcements becomes critical. HVDC technology, due to its controllability and efficiency over long distances, is expected to play a growing role in future grid developments. The study is conducted within the framework of zonal modelling using Antares, a widely used tool for adequacy and economic simulations of power systems developed by RTE. In this approach, the network is represented through interconnected zones rather than detailed nodal models, which allows for large-scale and long-term simulations while preserving key physical constraints. In power system studies, key indicators such as overflow and redispatching cost are widely used to assess network constraints and the economic efficiency of the system. Overflow represents the amount of energy that would have been transmitted if line capacities were not limiting, while redispatching cost reflects the cost of adjusting the generation plan to manage these constraints. However, the introduction of HVDC inside n HVAC network can significantly bias these indicators if not properly represented. Several modelling approaches are analyzed, including fixed border exchange, AC emulation with finite and infinite capacities, and the use of Optimal Power Flow (OPF) time series. These methods are evaluated on both fictional test cases and a realistic case study: the GiLA project, a double HVDC link connecting offshore wind farms along the French Atlantic coast. The comparison focuses on their ability to produce reliable overflow and redispatching indicators while avoiding artificial distortions of network flows. The results show that AC emulation with finite capacity introduces significant biases, notably by artificially reducing network flows, which leads to an underestimation of overflow and distorts redispatching costs. Infinite AC emulation mitigates some of these effects but remains less robust in low-congestion scenarios. In contrast, the OPF time series method consistently provides reliable and physically meaningful indicators across all tested configurations. Moreover, its robustness to variations in network conditions allows the reuse of time series across multiple scenarios, reducing computational effort. The study concludes that the OPF time series approach is the most suitable method for HVDC modelling in prospective studies, ensuring accurate assessment of network constraints and supporting future analyses conducted by RTE.