An Optimization Method for the Configuration of Inter Array Cables for Floating Offshore Wind Farm

Abstract

IFP Energies nouvelles (IFPEN) is involved for many years in various projects for the development of floating offshore wind turbines. The commercial deployment of such technologies is planned for 2020. The present paper proposes a methodology for the numerical optimization of the inter array cable configuration. To illustrate the potential of such an optimization, results are presented for a case study with a specific floating foundation concept [1]. The optimization study performed aims to define the least expensive configuration satisfying mechanical constraints under extreme environmental conditions. The parameters to be optimized are the total length, the armoring, the stiffener geometry and the buoyancy modules. The insulated electrical conductors and overall sheath are not concerned by this optimization. The simulations are carried out using DeepLines™, a Finite Element software dedicated to simulate offshore floating structures in their marine environment. The optimization problem is solved using an IFPEN in-house tool, which integrates a state of the art derivative-free trust region optimization method extended to nonlinear constrained problems. The latter functionality is essential for this type of optimization problem where nonlinear constraints are introduced such as maximum tension, no compression, maximum curvature and elongation, and the aero-hydrodynamic simulation solver does not provide any gradient information. The optimization tool is able to find various local feasible extrema thanks to a multi-start approach, which leads to several solutions of the cable configuration. The sensitivity to the choice of the initial point is demonstrated, illustrating the complexity of the feasible domain and the resulting difficulty in finding the global optimum configuration.

Parametric study of dynamic inter-array cable systems for floating offshore wind turbines

“…As first full-scale demonstrators for floating wind turbines only have emerged during last decade, field experience with dynamic umbilicals in this area is hardly available [9]. In literature, findings relating to umbilical shapes are coming from few experimental [30,31] and some numerical investigations [30,[32][33][34][35].…”

“…Poirette et al [33] present a lazy wave optimization tool based on their in-house Sequential Quadratic Approximation algorithm coupled with the software Deeplines. They examine production and storm load cases for a fullscale floating wind turbine model.…”

A Fundamental Study on Inter-Array Cabling Methods Between Two Floating Offshore Wind Turbines in Shallow Waters

“…The study offers significant insights into the structural reliability of dynamic power cables in offshore wind applications, highlighting the importance of considering realistic environmental loads in cable design and reliability assessment. Poirette et al (2017) presented a novel optimization methodology for the configuration of inter-array cables in floating offshore wind farms. This study utilizes FEM hydrodynamic simulations in conjunction with a derivative-free Sequential Quadratic Approximation (SQA) optimization algorithm.…”