Selection of Wind Direction Segment Size in Wind Farm Layout Optimization

• Author / Creator

  Ge, Siyun

• Wind energy is a popular electricity resource across the world in the last few decades and is becoming increasingly important. In wind farm constructions, wake effect is an inevitable problem to be addressed. The wake generated by the upstream wind turbines may decrease the wind speed and reduce the power output of the downstream wind turbines, which will influence the power generation capacity of the wind farm. Therefore, mitigating the wake effect is important in wind energy studies.
  Wind farm layout optimization is one of the most effective ways to mitigate the wake effect, aiming to minimize the energy loss due to wake effect by optimizing the positions of wind turbines. Wake effect is sensitive to wind directions, which are typically divided into equally spaced segments in wind resource modeling. Use of an inappropriate wind direction segment size in wind farm layout optimization may lead to unreliable optimization results or high computing time during the optimization process. However, few studies investigated the selection of wind direction segment sizes in wind farm layout optimization. In reported studies, the selection of wind direction segment sizes is mainly based on the consistency of the optimization results without considering the computing time. The accuracy of the estimated wind farm power output was not verified properly, and wind farms with different sizes were not investigated when making recommendations.
  This thesis proposes a comprehensive approach for selecting proper wind direction segment sizes in wind farm layout optimization studies. Wind farm power output and its estimation accuracy, together with computing time, are considered in the optimization process. The proposed approach involves five steps: modeling the wind farm power output and defining the objective function, pre-processing the data of the target wind farm, selecting an appropriate wind resource sample size for wind farm layout optimization, evaluating the estimated power output of the target wind farm, and optimizing the wind farm layout using genetic algorithm (GA). The proposed approach is demonstrated by case studies.
  The results show that the wind direction segment size has a clear impact on wind farm layout optimization. Smaller wind direction segment sizes generally result in better layouts with higher wind farm power output. The computing time for the optimization process increases with the decrease of wind direction segment size. For wind farms of different sizes and number of wind turbines, we are able to recommend suitable wind direction segment sizes. By applying the proposed approach to the target wind farm, the power output and cost performance are improved compared with randomly designed layouts. The results also show that 1° is the most reliable, 1° to 15° are acceptable, and 3° is the optimal wind direction segment size.
  With the proposed approach, different wind farm power output models can be incorporated to select proper wind direction segment sizes in wind farm layout optimization. The results will benefit wind farm operators, wind farm developers and researchers in selecting recommended wind direction segment sizes in wind farm power output calculation and layout optimization.

• Subjects / Keywords

  • wind energy
  • wind farm layout
  • wind characteristics

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-6z7r-qn03

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.