Endüstri Mühendisliği Bölümü / Department of Industrial Engineering

Permanent URI for this collectionhttps://hdl.handle.net/11413/6819

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Browsing Endüstri Mühendisliği Bölümü / Department of Industrial Engineering by Author "Alabaş Uslu, Çiğdem"

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    A Holistic Approach For The Optimization of Offshore Wind Farm Layouts Considering Cable Layouts
    (2019-08) Alabaş Uslu, Çiğdem; ÜLKÜ, İLAYDA; 51700
    A wind farm, mainly, is composed of a set of turbines, one or more transmitters and a set of electrical cable connections between turbines and transmitters. Determination of turbine locations within the farm to maximize total power generation is called turbine location (TL) problem. Relative turbine positions affect the amount of overall energy because of wake effects. Determination of cable connections among turbines and transmitters to collect produced energy by turbines at transmitters is called cable layout (CL) problem. While TL problem is directly effective on the total energy production in the farm, CL problem indirectly affects the total energy due to the power losses. In the literature, TL and CL problems are solved sequentially where the layout found by solving of TL is used as an input of CL problem. To minimize wake effects in TL problem, distances between turbine pairs should be increased, however, as the distances are increased the cable cost increases in CL problem. A new mathematical model is developed to deal with simultaneously solving of TL and CL problems. A set of test instances are used to show the performance of the proposed model. The experiments show the practical use of the proposed holistic model.
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    A new mathematicalpProgramming aapproach to wind farm layout problem under multiple wake effects
    (2019) Alabaş Uslu, Çiğdem; ÜLKÜ, İLAYDA; 51700; 126061
    Wind farm layout optimization is one of the challenging problems in thefield of renewable energy. In thepresent study, a new nonlinear mathematical model for layout of wind turbines under multiple wakeeffects is proposed considering two objective functions separately: maximization of total power pro-duction and minimization of cost per power. To incorporate multiple wake effects into the proposedmodel, Jensen's wake decay model is employed. It was proven that the proposed model has totallyunimodularity property and according to this property, relaxation of binary decision variables relatedwith the wind turbine locations makes the model relatively simple to solve. Computational study revealsthat results of total power production and cost of power obtained from the proposed model outperformthat of the previous studies in the literature on a set of example cases and therefore, can be used to layoutmore productive wind farms.
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    Optimization of cable layout designs for large offshore wind farms
    (John Wiley and Sons Ltd Wiley, 2020) Alabaş Uslu, Çiğdem; ÜLKÜ, İLAYDA
    Installation of a wind farm exposes several problems such as site selection, placement of wind turbines in the site, and designing of cable infrastructure within the farm. The latter problem, called cable layout design, is the determination of cable connections among turbines and one or more transmitters such that energies generated by turbines will be sent through the cable routes, and eventually gathered at the transmitter(s). This problem is especially important for offshore wind farms where the featured and expensive cables are used. The main objective of the present study is to address the cable layout design problem of offshore wind farms to reduce cable costs in the design using optimization-based approaches. The problem, firstly, is modelled as a mixed integer linear program (MIP) under a set of real-life constraints such as different cable and transmitter types and non-crossing connections between the turbines. Then, a novel mathematical model, which is a modification of the MIP model by imposing several heuristic rules, is proposed to solve the layout problem of large offshore wind farms. Experiments on a set of small- and moderate-sized test instances reveal that the heuristic model, MIP_H, reduces the computer time nearly 55% compared to that of MIP model while the average cable costs generated by the models are close to each other. MIP_H, besides its efficiency, provides more cost-effective layouts compared to MIP model for large-sized real-life examples. Additionally, a comparative study on MIP_H and existing methods in the literature shows that MIP_H is able to solve all instances of the real-life examples providing less cable costs in average.
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    Wind Farm Layout Optimization to Maximize Total Power Production
    (E3S Web of Conferences, 2018) Alabaş Uslu, Çiğdem; ÜLKÜ, İLAYDA; 51700; 126061
    With the rapid increase in energy demand, renewable energy has been considered as an alternative energy resource around the world. A new nonlinear mathematical model is developed in the presented study and a comparison is obtained with a mathematical modelling study from the literature. The results superior according to power generation under a single wind direction. Jensen’s wake decay model is used to state multiple wake effect among the turbines. The power production is maximized in terms of the minimization of wake effects. Mathematical formulations are represented and compared with the model from the literature. The generated layouts are presented and expected power among the Introduction turbines are significantly improved.