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1、本 科 毕 业 论 文电网过电压分析与防护设计Overvoltage Analysis and Protection Design for Power Grid学生学号：学生姓名：专业班级：指导教师姓名：指导教师职称：2015 年 6 月III电网过电压分析与防护设计专业班级： 学生姓名：指导教师： 教师职称：摘 要：随着社会经济的发展,电能的需求量日益增大,电力系统向远距离、大容量、超高压方向发展。电力系统中经常发生过电压事故,其中雷害事故一般占电力系统事故的 50%以上。根据过电压的特性,釆取合理防雷措施,对保证电力系统正常运行具有重要意义。本论文首先描述了电力系统中过电压的类型和特点；主
2、要阐述了雷电过电压，包括雷电的形成，雷电放电的三个阶段，雷暴日和雷暴小时、雷电流等值波形等雷电参数。直击雷过电压和感应雷过电压的雷放电计算模型；然后以 500kV 变电站雷击事故为例，利用ATP-EMTP 软件仿真雷电暂态过程。通过选择不同的雷击点，观察仿真所得的雷电波波形和不同部位三相导线上的电压波形；可以得出，雷击点离变电站越近，变电站内雷电侵入波幅值越高。可以安装相应的金属氧化物避雷器，限制在变压器的电压，使变压器得到相应的保护。根据不同电力设备雷击过电压的主要来源，为了躲避和限制雷电的危害，可以采用装设避雷针、避雷线、避雷器等避雷装置；直击雷防护主要采用装设避雷针或避雷线,侵入波防护主
3、要釆用装设避雷器;根据不同雷击分析了避雷针和避雷线的防雷原理及保护范围。针对输电线路、发电厂和变电所遭受雷击的各种情况，全面考虑线路的重要程度、系统运行方式、线路经过地区雷电活动的强弱、地形地貌的特点、土壤电阻率的高低等条件，结合当地原有线路运行经验，根据技术经济比较的结果，因地制宜地采取合理的防雷保护措施。关键词：过电压 雷电过电压 避雷针 ATP-EMTP 过电压防护IIOvervoltage Analysis and Protection Design for Power GridAbstract： With development of the social economy, the
4、demand for electricity is rapidly increasing, power system develops with long range, high-capacity, ultra-high voltage. Overvoltage accident happens frequently in power system, in which lightning overvoltage accounts for more than 50%.According to the characteristics of overvoltage, it is very meani
5、ngful for ensure normal operation of power system to take reasonable lightning protection measures. Firstly, this paper describes the types and characteristics of the overvoltage in power system;This paper mainly expounds the lightning overvoltage, including the formation of lightning, the three sta
6、ges of the lightning discharge, the lightning parameters of the thunderstorm days and the thunderstorm hours and the equivalent waveforms of the thunder and lightning current. Lightning discharge calculation model of lightning overvoltage and induced lightning overvoltage. Then, taking the lightning
7、 fault of 500kV substation as an example, the transient process of lightning transient process is simulated by ATP-EMTP software. By choosing different lightning points, the waveforms of lightning waveforms and different positions of three-phase conductors are observed;It can be concluded that the h
8、igher the lightning wave amplitude in the substation is higher. By installing the corresponding metal oxide surge arrester, the transformer voltage can be limited, and the transformer can be protected.According to the main source of Lightning Overvoltage in different power equipment, lightning condu
9、ctor, lightning rod and lightning arrester can be used in order to avoid and limit the damage of lightning; Lightning protection mainly adopts installed lightning rod or wire, intrusive wave protection mainly adopts the arrester. According to different lightning, the lightning protection principle a
10、nd protection range of lightning rod and lightning rod is analyzed. According to the transmission line, power plant and substation from lightning, comprehensively consider the importance of the line, the system operation mode, the intensity of the lightning activity, the characteristic of the terrai
11、n, the height of the soil resistivity, etc. Combined with local original line operation experience, according to the result of the comparison of the technology economy, the reasonable lightning protection measures are adopted according to the measures to the local conditions.Key wordsOvervoltage, Lightning Overvoltage, Lightning Rod, ATP-EMTP,Overvoltage ProtectionIII目 录摘要 .I关键词 .I引言 .1第一章概述 .21.1 课题研究的背景及意义 .21.2 国内外研究现状 .21.3 本论文主要内容 .3第二章雷电过电压 .52.1 过电压的类型和特点 .52.1.1 过电压的危害 .62.2 雷电过电压的产生 .72.2.1 雷云的形成 .72.2.2 雷电放电过程 .
