风电场的选址与风能资源评估及其后评价

SITE SELECTION AND WIND ENERGY RESOURCE EVALUATION OF WIND FARMS AND ITS POST EVALUATION

风电场选址的优劣与风能资源评估的准确性息息相关,决定了风电项目的成功与否。从工程实践的角度,对风电场在场址选择、测风方案、数据分析、模型计算过程中的遇到的几个关键问题进行概述,并以贵州省处于复杂地形的某风电场为例进行后评价,分析理论计算得到的发电量与实际发电量的差异及差异产生原因。结果显示:1)场址选择方面,借助高精度风能资源图谱,通过叠加土地利用现状图、生态红线范围图等方式,选出资源相对较好的区域作为潜在规划区域,再通过现场实地勘查,排除限制区域;2)测风方案方面,需有足够的测风塔数量和充足的测风时间,测风塔安装位置尽可能覆盖场区内多样化的地形条件;3)数据分析方面,测风数据的插补可选用多种拟合方法,对比插补后风速、威布尔分布的变化,尽量降低因缺少测风数据带来的计算误差;4)模型计算方面,应先验证测风塔在数字化地形图上的位置与实际地形是否吻合,视项目所在地地形复杂程度、地表特征,选择适用的计算模型,海上风电项目和陆上大基地风电项目应重点关注尾流模型的适用性和尾流衰减常数的取值;5)风电场后评价方面,开展基于风能资源评估的风电场后评价,找寻导致风电场实际运行时的发电量与设计发电量差异的因素,有助于减少之后风电场在设计阶段的误差。以期本研究可为后续风电场测风塔选址、风能资源评估提供参考。

The quality of wind farm site selection is closely related to the accuracy of wind energy resource assessment,determining the success or failure of wind power projects.This paper provides an overview of several key issues encountered by wind farms in site selection,wind measurement schemes,data analysis,and model calculation from the perspective of engineering practice.Taking a wind farm in Guizhou Province,which is located in a complex terrain,as an example,a post evaluation is conducted to analyze the differences between the theoretically calculated and actual power generation,as well as the reasons for the differences.The results show that:1)In terms of site selection,with the help of high-precision wind energy resource maps,areas with relatively good resources are selected as potential planning areas by overlaying land use status maps,ecological red line range maps,and other methods.Then,through on-site investigation,restricted areas are eliminated.2)In terms of wind measurement plan,there should be sufficient number of wind measurement towers and sufficient wind measurement time,and the installation location of wind measurement towers should cover the diverse terrain conditions in the site area as much as possible.3)In terms of data analysis,multiple fitting methods can be used for interpolation of wind measurement data,comparing the changes in wind speed and Weibull distribution after interpolation to minimize calculation errors caused by the lack of wind measurement data.4)In terms of model calculation,it is necessary to first verify whether the position of the wind measurement tower on the digital terrain map matches the actual terrain.Depending on the complexity of the terrain and surface characteristics of the project location,suitable calculation models should be selected.For offshore wind power projects and onshore large-scale base wind power projects,the applicability of the wake model and the value of the wake attenuation constant should be emphasized.5)In terms of post evaluation of wind farms,conducting post evaluation based on wind energy resource assessment to identify factors that lead to differences between the actual and designed power generation of wind farms during operation can help reduce errors in the design phase of wind farms in the future.In the hope that this study can provide reference for the selection of wind measurement towers and wind energy resource assessment in subsequent wind farms.