近年来，在电力设备绝缘技术领域中，局部放电检测技术广受关注。广东省电力科学研究院高压所一批专家学者多年来致力于该专业的研究与应用，几年来积累了不少经验，为更好地推广应用技术，特编写了本书。本书主要包括7 章内容，分别是概述、局部放电理论、局部放电特高频电磁波在GIS 中的传播特性、局部放电特高频检测技术基础、局部放电特高频检测的标定、局部放电特高频定位技术、特高频检测技术在GIS 局部放电状态监测中的应用。
局部放电好比是电气设备体内的癌细胞，它伴随着设备内部绝缘材料或结构的微观缺陷而生。局部放电因其电、热、机械和化学效应会对绝缘材料造成侵蚀并加速材料的老化和劣化，就像癌细胞的扩散，并将最终引发绝缘击穿故障。电气设备局部放电发生的原因多种多样，如绝缘设计不合理，绝缘材料中存在杂质、气泡或裂纹，电极表面粗糙或因划伤而引发的尖刺，设备装配中的偏差，设备运输或试验过程中带来的各类损伤，设备在运行过程中因震动而导致的连接部件的松动，以及绝缘的老化等，这些因素均会导致设备内部电场应力集中而引发局部放电。局部放电本身并不等同于绝缘故障，一般可以在电气设备运行过程中存在相当长的时间。局部放电的发生、发展及其破坏作用具有很大的随机性，并因绝缘材料、绝缘结构、运行工况以及周围环境等众多因素的不同而不同，这也使得局部放电状态及危害程度的评估十分复杂。国际上最早提出局部放电这一概念是20 世纪初，到20 世纪80 年代就已经建立了国际公认的测量标准（IEC 270）。长期以来局部放电现象一直受到人们的高度重视，局部放电测量被广泛应用于高压设备的型式试验、出厂试验、交接试验以及绝缘预防性试验，成为检验设备质量工艺水平及绝缘性能的关键参数，同时也是反映高压设备早期绝缘缺陷最灵敏和最有效的指标。多年以来，人们也一直致力于将局部放电检测应用于设备的带电测试，然而由于局部放电带电检测情况下的灵敏度、高压设备工作现场复杂的电磁干扰等技术瓶颈的制约，局部放电带电检测和在线监测技术的发展非常缓慢。自1986 年英国Strathclyde 大学在苏格兰的Torness 核电站安装了第一套气体绝缘金属封闭开关设备（GIS）的局部放电特高频监测装置以来，局部放电特高频检测技术日益成为该领域研究的热点，发表的论文不下数百篇。特高频法（ultra-high frequency，300MHz～3GHz）就是利用GIS 局部放电辐射出的特高频电磁波信号进行检测的一种方法。研究表明，GIS 局部放电将会产生很陡的脉冲电流，并向四周辐射多种频率的电磁波，通过特高频传感器接收其中300MHz～3GHz 的电磁波信号，可实现对局部放电的检测和定位。由于特高频法具有抗干扰能力强、灵敏度高等特点，而且这种非接触式的测量方式对于二次设备和检测人员而言都更安全，系统结构简单，特别适合于在线监测，因而较之于其他检测方法具有明显的优势。局部放电特高频在线检测技术的应用则随着北京2008 奥运会的举办而掀起了高潮，也正是自2008 年起，国家电网公司陆续发布了十余项规范输变电设备状态检修的企业标准，广东电网公司则于2009 年底首次启动了GIS 局部放电特高频在线监测系统的大规模招标采购。在国家电网公司十二五规划中，智能电网建设引领能源产业发展的引擎，智能设备及状态评估均离不开在线检测技术的支撑，局部放电特高频检测技术赫然在列。然而，在局部放电特高频在线检测技术迅速发展的过程中，也暴露出一系列的问题：（1）相关技术标准、规范不健全，缺乏统一有效的指导；（2）设备运行现场复杂的放电类干扰依然严重影响特高频检测的应用；（3）特高频局部放电检测技术在故障诊断和状态评估的理论和应用均不完善；（4）特高频局部放电检测技术本身应用的瓶颈较高，难度较大。这些问题导致人们一度对局部放电特高频检测技术存在很大争议，令现场从事运检工作的技术人员感到困惑。广东电网公司电力科学研究院（简称广东电科院）从20 世纪90 年代末期开始至今，一直持续进行局部放电特高频检测技术研究和工程应用，近年来开展了GIS 标准化相关的一系列关键技术研究，首次提出并建立了国内外首个GIS 全尺寸标定平台、开发了现场灵敏度校核系统，技术成果全面应用于广东电网公司GIS 生命周期管理，极大地提高了GIS的运行可靠性，2012 年实现GIS 事故率同比下降54%。本书基于广东电科院近年来在GIS 局部放电特高频检测技术取得的应用成果，参考国内外相关著作和文献编著而成，在此向相关著作和文献的作者表示衷心的感谢。本书在编写过程中得到了华北电力大学高压教研室师生的大力支持，吸纳了郑书生、詹花茂、王彩雄、魏振等各位老师和博士的研究资料及成果，全书得到了李成榕教授的悉心指导。在此向华北电力大学各位老师和学生一并表示感谢！由于学识水平有限，成书仓促，不当之处敬请谅解，并请不吝批评指正！编著者2016 年5 月
前言
1 概述··············································································································1
1.1国内外状态检修背景简介······································································1
1.2局部放电检测技术··················································································4
1.3局部放电特高频在线检测技术······························································6
1.4局部放电特高频检测技术的主要内容················································12
2局部放电理论·····························································································14
2.1局部放电的概念···················································································14
2.2局部放电的物理过程············································································15
2.3局部放电的基本参数············································································24
2.4局部放电辐射原理················································································26
2.5常规局部放电与特高频局部放电信号之间的关系·····························30
3局部放电特高频电磁波在GIS中的传播特性·········································33
3.1波导理论·······························································································33
3.2 GIS中电磁波传播规律仿真·································································34
3.3 GIS结构对电磁波传播的影响·····························································43
3.4 GIS中局部放电特高频电磁波传播特性的试验研究··························47
4局部放电特高频检测技术基础··································································58
4.1天线接收原理·······················································································58
4.2局部放电特高频检测系统····································································59
4.3局部放电特高频信号的时频特征························································62
4.4局部放电特高频检测的抗干扰技术····················································64
4.5局部放电特高频检测的模式识别························································78
5局部放电特高频检测的标定·····································································92
5.1时域参考法测量原理············································································93
5.2局部放电特高频检测性能的关键指标·················································96
5.3基于GTEM小室的局部放电特高频标定方法····································99
5.4 GIS局部放电标定结果的检验···························································102
6局部放电特高频定位技术·······································································105
6.1 GIS局部放电特高频定位常用的方法···············································105
6.2时间差定位方法··················································································107
7特高频检测技术在GIS局部放电状态监测中的应用····························121
7.1概述·····································································································121
7.2 GIS局部放电特高频检测技术的应用···············································123
7.3 GIS局部放电特高频检测典型案例分析···········································126
参考文献··············································································································182
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