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

2017 ◽  
Author(s):  
Yann Poirette ◽  
Martin Guiton ◽  
Guillaume Huwart ◽  
Delphine Sinoquet ◽  
Jean Marc Leroy
Keyword(s):  
Wind Farm ◽  
Optimization Problem ◽  
Initial Point ◽  
Trust Region ◽  
Optimization Method ◽  
Global Optimum ◽  
Offshore Wind ◽  
Finite Element Software ◽  
Constrained Problems ◽  
Floating Offshore Wind Turbines

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.

The Improvement of Newton Method and the Validation of Optimization Idea of Blind Walking Repeatedly

2011 ◽  
Vol 250-253 ◽  
pp. 4061-4064
Author(s):  
Chun Ling Zhang
Keyword(s):  
Saddle Point ◽  
Newton Method ◽  
Optimization Problem ◽  
Initial Point ◽  
Optimization Method ◽  
Maximum Point ◽  
Optimal Result ◽  
Feasible Domain ◽  
Parallel Arithmetic ◽  
Newton Direction

The existence of maximum point, oddity point and saddle point often leads to computation failure. The optimization idea is based on the reality that the optimum towards the local minimum related the initial point. After getting several optimal results with different initial point, the best result is taken as the final optimal result. The arithmetic improvement of multi-dimension Newton method is improved. The improvement is important for the optimization method with grads convergence rule or searching direction constructed by grads. A computational example with a saddle point, maximum point and oddity point is studied by multi-dimension Newton method, damped Newton method and Newton direction method. The importance of the idea of blind walking repeatedly is testified. Owing to the parallel arithmetic of modernistic optimization method, it does not need to study optimization problem with seriate feasible domain by modernistic optimization method.

scholarly journals Parent Nested Optimizing Structure for Vibration Reduction in Floating Wind Turbine Structures

2020 ◽  
Vol 8 (11) ◽  
pp. 876
Author(s):  
Gwanghee Park ◽  
Ki-Yong Oh ◽  
Woochul Nam
Keyword(s):  
Global Minimum ◽  
Optimization Method ◽  
Offshore Wind ◽  
Design Parameters ◽  
Optimization Approach ◽  
Offshore Wind Turbines ◽  
Swarm Algorithms ◽  
Floating Offshore Wind Turbines ◽  
Artificial Fish Swarm ◽  
Computationally Intensive

A tuned mass damper (TMD) is a system that effectively reduces the vibrations of floating offshore wind turbines (FOWTs). To maximize the performance of TMDs, it is necessary to optimize their design parameters (i.e., stiffness, damping, and installation location). However, this optimization process is challenging because of the existence of multiple local minima. Although various methods have been proposed to determine the global minimum (e.g., exhaustive search, genetic algorithms, and artificial fish swarm algorithms), they are computationally intensive. To address this issue, a novel optimization approach based on a parent nested optimizing structure and approximative search is proposed in this paper. The approximative search determines an initial parameter set (close to the optimal set) with fewer calculations. Then, the global minimum can be rapidly determined using the nested and parent optimizers. The effectiveness of this approach was verified with an FOWT exposed to stochastic winds. The results show that this approach is 30–55 times faster than a conventional global optimization method.

scholarly journals Structural Optimization Method for the Transition Section in Composite Bucket Foundations of Offshore Wind Turbines

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3230 ◽  
Author(s):  
Puyang Zhang ◽  
Yunlong Xu ◽  
Conghuan Le ◽  
Hongyan Ding ◽  
Yaohua Guo
Keyword(s):  
Structural Optimization ◽  
Hybrid Genetic Algorithm ◽  
Optimization Method ◽  
The Body ◽  
Offshore Wind ◽  
Utilization Rate ◽  
Force Transmission ◽  
Transition Section ◽  
Finite Element Software ◽  
Thin Walled

A two-step structural optimization method was proposed to select the transition section of a composite bucket foundation (CBF). In the first step, based on the variable density method, a solid isotropic microstructures with penalization (SIMP) interpolation model was established under specific load conditions and boundary conditions. The solution of force transmission path and the topology of the transition section in six forms (e.g., linear, arc-shaped, linear thin-walled, and arc-shaped thin-walled) were optimized. Afterwards, finite element software ABAQUS was used to verify this model. Results show that the utilization rate of the arc-shaped thin-walled structure was the largest, and its basic transmission force was more straightforward together with smaller cross-section size at the same height and smaller influence on spoiler flow. In the second step, the detailed optimization of CBF was carried out using mathematical programming. Under the premise of minimum total construction cost, the body shape parameters of each part were set as design variables satisfying the corresponding strength, stiffness, and stability conditions; meanwhile, the minimum total structure weight was set as the objective function. MATLAB was used to solve the sequence quadratic programming (SQP) algorithm and hybrid genetic algorithm, and the optimal body parameters were obtained.

Harmonizing the Mooring System Reliability of Multiline Anchor Wind Farms

2021 ◽  
Vol 7 (4) ◽  
Author(s):  
Spencer T. Hallowell ◽  
Sanjay R. Arwade ◽  
Brian D. Diaz ◽  
Charles P. Aubeny ◽  
Casey M. Fontana ◽  
...  
Keyword(s):  
Wind Turbines ◽  
System Reliability ◽  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Line System ◽  
Offshore Wind Turbines ◽  
Anchor System ◽  
Floating Offshore Wind Turbines ◽  
Additional Safety

Abstract One of many barriers to the deployment of floating offshore wind turbines is the high cost of vessel time needed for soil investigations and anchor installation. A multiline anchor system is proposed in which multiple floating offshore wind turbines (FOWTs) are connected to a single caisson. The connection of multiple FOWTs to a single anchor introduces interconnectedness throughout the wind farm. Previous work by the authors has shown that this interconnectedness reduces the reliability of the FOWT below an acceptable level when exposed to survival loading conditions. To combat the reduction in system reliability an overstrength factor (OSF) is applied to the anchors functioning as an additional safety factor. For a 100 turbine wind farm, single-line system reliabilities can be achieved using the multiline system with an OSF of 1.10, a 10% increase in multiline anchor safety factors for all anchors in a farm.

3D FEM Analysis on Bearing Capacity Behaviors of the Multi-Piles Foundation for Offshore Wind Turbines

2012 ◽  
Vol 170-173 ◽  
pp. 2233-2242
Author(s):  
Xiao Wei Tang ◽  
Qi Shao ◽  
Bin Xue Liu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Wind Turbines ◽  
Wind Farm ◽  
Offshore Wind ◽  
Combined Loading ◽  
Hangzhou Bay ◽  
Offshore Wind Turbine ◽  
Offshore Wind Turbines ◽  
Finite Element Software

With the fast development of technology, offshore wind power generation is playing a major role for developing renewable sources in the whole world nowadays. According to the proposed Hangzhou Bay wind farm in China, using general-purpose finite element software, bearing capacity behaviors of the multi-piles foundation for offshore wind turbine are simulated in this paper by the 3D finite element method. The Mohr - Coulomb model is adopted as the elastic - plastic constitutive model of the soil and also the Coulomb Friction model as the pile - soil contact model. The bearing capacity behavior of multi-piles foundation for offshore wind turbines under monotonic and combined loading are discussed, also the bearing capacity behaviors by changing diameters, spaces of piles and loading directions as well.

Efficient Multiline Anchor Systems for Floating Offshore Wind Turbines

2016 ◽  
Author(s):  
Casey M. Fontana ◽  
Sanjay R. Arwade ◽  
Don J. DeGroot ◽  
Andrew T. Myers ◽  
Melissa Landon ◽  
...  
Keyword(s):  
Dynamic Simulation ◽  
Wind Turbines ◽  
Wind Farm ◽  
Offshore Wind ◽  
Wave Loading ◽  
Peak Demand ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines ◽  
Anchor Systems ◽  
Floating Platforms

A mooring and anchoring concept for floating offshore wind turbines is introduced in which each anchor moors multiple floating platforms. Several possible geometries are identified and it is shown that the number of anchors for a wind farm can be reduced by factors of at least 3. Dynamic simulation of turbine dynamics for one of the candidate geometries and for two directions of wind and wave loading allows estimation of multiline anchor forces the preview the types of loads that a multiline anchor will need to resist. Preliminary findings indicate that the peak demand on the anchor may be reduced by as much as 30% but that anchors used in such a system will need to be able to resist multi-directional loading.

scholarly journals A comparison study on jacket substructures for offshore wind turbines based on optimization

2019 ◽  
Vol 4 (1) ◽  
pp. 23-40 ◽  
Author(s):  
Jan Häfele ◽  
Cristian G. Gebhardt ◽  
Raimund Rolfes
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Optimization Problem ◽  
Gaussian Process Regression ◽  
Offshore Wind ◽  
Mixed Integer ◽  
Fixed Integer ◽  
Practical Applications ◽  
Offshore Wind Turbines ◽  
Design Variables

Abstract. The structural optimization problem of jacket substructures for offshore wind turbines is commonly regarded as a pure tube dimensioning problem, minimizing the entire mass of the structure. However, this approach goes along with the assumption that the given topology is fixed in any case. The present work contributes to the improvement of the state of the art by utilizing more detailed models for geometry, costs, and structural design code checks. They are assembled in an optimization scheme, in order to consider the jacket optimization problem from a different point of view that is closer to practical applications. The conventional mass objective function is replaced by a sum of various terms related to the cost of the structure. To address the issue of high demand of numerical capacity, a machine learning approach based on Gaussian process regression is applied to reduce numerical expenses and enhance the number of considered design load cases. The proposed approach is meant to provide decision guidance in the first phase of wind farm planning. A numerical example for a National Renewable Energy Laboratory (NREL) 5 MW turbine under FINO3 environmental conditions is computed by two effective optimization methods (sequential quadratic programming and an interior-point method), allowing for the estimation of characteristic design variables of a jacket substructure. In order to resolve the mixed-integer problem formulation, multiple subproblems with fixed-integer design variables are solved. The results show that three-legged jackets may be preferable to four-legged ones under the boundaries of this study. In addition, it is shown that mass-dependent cost functions can be easily improved by just considering the number of jacket legs to yield more reliable results.

scholarly journals Minimizing Energy Loss by Coupling Optimization of Connection Topology and Cable Cross-Section in Offshore Wind Farm

2019 ◽  
Vol 9 (18) ◽  
pp. 3722
Author(s):  
Wang ◽  
Wu ◽  
Han ◽  
Wang
Keyword(s):  
Power Systems ◽  
Power System ◽  
Energy Loss ◽  
Cross Section ◽  
Wind Farm ◽  
Optimization Method ◽  
Offshore Wind ◽  
Optimal Topology ◽  
Offshore Wind Farm ◽  
Resistance Level

The cable cross section of an offshore wind farm power system is conventionally determined on the basis of the maximum current carrying capacity. However, this criterion cannot be matched and optimized with connection topology, which may lead to a large overall resistance level in the topology, thereby causing severe energy loss. In this pursuit, the present work envisages the establishment of a coupling optimization method of connection topology and cable cross-section planning for the first time. Based on this method, the power system of a small discrete wind farm is optimized and its results are compared with the results of the traditional design methods. The results indicate that an optimal matching of connection topology and cable cross section can be achieved using the proposed method. Besides, the optimal topology obtained uses more branches, and the large cross-section cables are reasonably used on the large-current cable segments, thus dramatically reducing the energy loss and minimizing the total cost of the power system. The proposed method is very versatile and suitable for the optimization of power systems containing any number of wind turbines and substations. Moreover, it can be combined with any evolutionary algorithm.

Chaotic Ant Swarm Based Parameter Estimation of Induction Motor from Manufacturer Data

2013 ◽  
Vol 341-342 ◽  
pp. 1403-1407
Author(s):  
Yan Jie Li ◽  
Zhu Zhi Jia
Keyword(s):  
Numerical Simulation ◽  
Parameter Estimation ◽  
Induction Motor ◽  
Motor Performance ◽  
Optimization Problem ◽  
Optimization Method ◽  
Global Optimum ◽  
Equivalent Circuit Parameters ◽  
Simulation Results ◽  
Swarm Algorithm

A method of parameter estimation of induction motor based on optimization using a chaotic swarm algorithm is presented. The parameter estimation methodology describes a method for estimating the steady-state equivalent circuit parameters from the motor performance characteristic, which is normally available from manufacturer data or from tests. The optimization problem is formulated as multi-objective function to minimize the error between the estimated and the manufacturer data. Chaotic ant swarm algorithm is a novel optimization method, which has the ability of global optimum search. A numerical simulation on the test motor is conducted. Simulation results show that the proposed method is effective in parameter estimation of the induction motor.

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