【作者】 王理；

【导师】 李欣然； 钱军；

【作者基本信息】 湖南大学 ， 电气工程（专业学位）， 2020， 硕士

【摘要】 风能作为重要的可再生能源,在解决化石能源危机具有重要作用。随着经济的不断发展,世界范围内的风电场规模及风电装机容量快速增加,然而受限于选址条件,风电机组建设环境等因素影响,风电场遭受雷电事故的几率极大,风电场在雷击时的安全运行受到越来越多关注。正常情况下,当风机遭遇雷击时,雷电流将通过风机叶片传递至风电机组整个外部塔体系统,然后经过接地装置流入大地。在此过程中,若风机防雷接地装置异常,雷电流将会严重干扰或损坏风机及其内部弱电系统,影响风电场和电力系统的稳定运行,因此研究如何提高风电机组防雷接地水平,保障风机在雷击事故中稳定运行具有极大紧迫性和实际意义。本文首先介绍了雷电的放电过程及其对风电机组的影响,基于风电机组各部分简化模型,分析了雷电对风电机组的雷击部位和雷击率,分析了雷击事故的危害和一般防护措施;然后,结合雷电流影响机理,分析了风电场接地技术中的共性问题,引出了风电机组接地电阻概念,给出了接地装置常用降阻原理及方法;基于理论知识,以湖南天塘山风电场箱式变压器屡次遭受雷击损坏为背景,通过搭建风机叶片、塔筒、控制电缆、箱式变压器、避雷器和接地装置等设备的物理模型,建立EMTP仿真模型进行防真,结合湖南电网雷电相关数据以及实地测量风电机组附近土壤电阻率、接地阻抗和接地装置的完整性,分析雷电流在风机发、变机组中的运行方式;最后,分析了风电机组布局和不同雷击位置对过电压分布的影响。通过对风电场雷电暂态过电压仿真分析,了解雷击对风电场各个电气设备的影响,提出解决措施,为工程施工提供参考依据,减少雷击灾害给该风电场带来的经济损失。更多还原

【Abstract】 As an important renewable energy,wind energy plays an important role in solving the fossil energy crisis.Wit h the cont inuous development of the economy,the scale of wind farms worldwide and the installed capacit y of wind power have increased rapidly.However,due to the impact of site select ion condit ions and the construct ion environment of wind turbines,wind farms are highly likely to suffer from lightning accidents.More and more attent ion has been paid to safe operat io n during lightning strikes.Under normal circumstances,when the wind turbine encounters a lightning strike,the lightning current will be transmitted to the ent ire external tower system of the wind turbine thr ough the wind turbine blades,and then flow into the earth through the grounding device.In this process,if the wind turbine lightning protect ion grounding device is abnormal,the lightning current will seriously interfere or damage the wind turbine and its internal weak current system,and affect the stable operat ion of the wind farm and power system.Therefore,research how to improve the lightning protect ion grounding level of wind turbines to ensure The stable operat ion of wind turbines in lightning ac cidents is of great urgency and pract ical significance.This thesis first introduces the discharge process of lightning and its impact on wind turbines.Based on the simplified model of each part of the wind turbine,the lightning strike posit ion and rate of lightning on the wind turbine are analyzed,and the hazards of lightning accidents and general protect ion measures are analyzed;Combined with the mechanism of lightning current,the commo n problems in grounding technology of wind farms are analyzed,the concept of grounding resistance of wind turbines is derived,and the principles and methods of resistance reduct ion commo nly used for grounding devices are given.Based on theoret ical knowledge,the box-t ype in Hunan Tiantangshan wind farm Against the background of repeated lightning damage to the transformer,physical models of wind turbine blades,towers,control cables,box-t ype transformers and grounding devices were built,and an EMTP simulat ion model was established for ant i-realism,combined with t he lightning-related data of Hunan Power Grid and field measurement of wind turbines.The nearby soil resist ivit y,grounding impedance and the integrit y of grounding devices are analyzed,and the operat ion mode of lightning current in wind turbine generators and transformer units is analyzed.Finally,the influence of wind turbine layout and different lightning strike posit ions on overvoltage distribut ion is analyzed.Through the simulat ion analysis of the lightning transient overvoltage of the wind farm,we can understand the impact of lightning strikes on the various electrical equipment of the wind farm,propose solut ions,provide a reference for the construct ion of the project,and reduce the economic loss of the wind farm caused by the lightning disaster.更多还原