Cable Layout Optimization of Offshore Wind Farms Collection Systems

A mathematical program for global optimization of the cable layout of Offshore Wind Farms (OWFs) is presented. The model consists on a Mixed Integer Linear (MILP) program. Modern branch-and-cut solvers are able to solve largescale instances, defined by more than hundred Wind Turbines (WTs), and any number of Offshore Substations (OSSs). In addition to the MILP model to optimize total cable length or initial investment, a pre-processing strategy is proposed in order to incorporate total electrical power losses into the objective function. High fidelity models to calculate cables current capacities, spatial currents, and losses are adapted as well. The MILP model is embedded in an iterative algorithmic framework, consisting in solving sequentially a set of problems with increasing size of the feasible set, defining them as a set of candidate arcs. The applicability of the method is illustrated through three case studies of real large-scale wind farms. Results show that: i) feasible points can quickly be obtained in minutes, and ii) points near the global optimum with an imposed maximum tolerance, are calculable in reasonable computational time in the order of hours.