  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 Program (MILP). Modern branch-and-cut solvers are able to solve
large-scale instances, defined by more than hundred Wind Turbines (WTs), and a
reasonable 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 are adapted to calculate cables
current capacities, spatial currents. The MILP model is embedded in an
iterative algorithmic framework, consisting in solving a sequence of problems
with increasing size of the search space. The search space is defined as a set
of underlying candidate arcs. The applicability of the method is illustrated
through 10 case studies of real-world large-scale wind farms. Results show
that: (i) feasible points can quickly be obtained in seconds, (ii) points near
the global optimum with an imposed maximum tolerance, are calculable in
reasonable computational time in the order of hours, and (iii) the proposed
method compares favorably against a state-of-the art method available in
literature.
