输电线路杆塔雷电特性及接地装置降阻效果研究

发布时间：2018-01-14 09:22

本文关键词：输电线路杆塔雷电特性及接地装置降阻效果研究　出处：《华北电力大学(北京)》2016年硕士论文　论文类型：学位论文

【摘要】：在输电线路中,杆塔防雷水平是影响线路运行安全性及可靠性的关键因素。一方面,雷击杆塔会引发地面产生很高的跨步电压及接触电压,危及人身安全；另一方面,杆塔接地装置电阻偏高可能引发雷电反击导致线路跳闸。针对雷击后杆塔暂态电磁特性,本文基于CDEGS软件对雷电流建模方法及杆塔遭受雷击后地表电场、磁场的分布情况进行研究。进一步,结合MATLAB软件,对接地装置、雷电流幅值、土壤电阻率同雷击后地表最大跨步电压与杆塔底端最大接触电压间的变化规律进行分析计算,对杆塔雷击暂态的安全性进行论述。研究发现,在均匀土壤中,最大接触电压与最大跨步电压随着雷电流幅值、土壤电阻率的增大而增大,且存在较强的线性关系。针对杆塔接地装置在不同类型土壤中的降阻效果,本研究取均匀型、水平分层型、垂直分层型三种土壤,建立水平外延和水平垂直两种接地装置模型,对在不同土壤结构中延长接地装置放射线长度、改变垂直接地体个数、改变放射线角度等措施的降阻效果进行分析计算。结果证明,在高电阻率的均匀土壤中,随着外延放射线长度增长,接地电阻逐渐减小,当射线长度达到一定数值时,接地电阻减小的趋势减缓,降阻效果趋于饱和；对上层电阻率高,下层电阻率低的水平分层土壤,增设垂直接地体的降阻效果明显；在垂直分层型土壤中,合理调整接地装置外延放射线方向能有效降低接地电阻。最后,本文结合吉林市220kV金东甲线实地调研数据,针对其输电线路杆塔接地装置结构及土壤分层情况,对杆塔接地电阻进行仿真计算,根据线路实际运行情况及仿真结果提出合理的改造措施。利用CDEGS仿真平台的计算结果表明,不论杆塔所处土壤环境多么复杂,均可通过仿真计算配以降阻效果较好的接地装置,提出合理的接地装置设计与改造方案。本研究具有较高的工程实用价值。
[Abstract]:In the transmission line, lightning protection level is a key factor affecting the line operation safety and reliability. On the one hand, the lightning will lead to ground voltage step and touch voltage is high, endanger personal safety; on the other hand, grounding device of high resistance may lead to lightning counterattack lead line tripping. After the lightning the tower transient electromagnetic characteristics, this paper CDEGS software modeling method of lightning current and tower lightning after surface electric field based on the study of the distribution of the magnetic field. Further, combined with MATLAB software, grounding device, lightning current amplitude, soil resistivity with lightning after the maximum surface step voltage and tower bottom variation between the maximum touch voltage the analysis and calculation, discusses the safety of tower lightning transient. The study found that in the uniform soil, the maximum contact voltage and the maximum step voltage with thunder The current amplitude increases, the soil resistivity increases, and there is a strong linear relationship. The resistance reducing effect of grounding device in different types of soils, this research takes the uniform type, horizontal type, vertical type of three kinds of soil, establish the level of horizontal and vertical extension of two kinds of grounding device in the model. Different soil structure of extended grounding device radiation length, change the body number of vertical grounding resistance reduction effect, change of radiation angle measure is analyzed. Results show that in homogeneous soil high resistivity, along with the extension of the radiation length increases, the grounding resistance decreases when the ray length reaches a certain value slow down, the grounding resistance decreases, the resistance reducing effect is saturated; the upper level high resistivity, low resistivity and lower layer soil, the resistance reduction effect of additional vertical grounding body in vertical layered type; In the soil, reasonable adjustment of grounding device extension radiation direction can effectively reduce the grounding resistance. Finally, combining with the survey data of Jilin city 220kV Dongjia gold line, according to the structure of the device and the soil layer transmission line tower grounding, calculation of tower grounding resistance simulation, put forward reasonable improvement measures according to the actual line the operation and simulation results. The calculation results show that the CDEGS simulation platform, regardless of how complex the tower soil environment, the grounding device can be calculated by simulation with the drag reduction effect is good, puts forward the design and retrofit scheme of grounding device is reasonable. This research has high practical value.

【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM862

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