近年來，在電力設備絕緣技術領域中，局部放電檢測技術廣受關注。廣東省電力科學研究院高壓所一批專家學者多年來致力于該專業(yè)的研究與應用，幾年來積累了不少經(jīng)驗，為更好地推廣應用技術，特編寫了本書。本書主要包括7 章內容，分別是概述、局部放電理論、局部放電特高頻電磁波在GIS 中的傳播特性、局部放電特高頻檢測技術基礎、局部放電特高頻檢測的標定、局部放電特高頻定位技術、特高頻檢測技術在GIS 局部放電狀態(tài)監(jiān)測中的應用。
局部放電好比是電氣設備體內的癌細胞，它伴隨著設備內部絕緣材料或結構的微觀缺陷而生。局部放電因其電、熱、機械和化學效應會對絕緣材料造成侵蝕并加速材料的老化和劣化，就像癌細胞的擴散，并將最終引發(fā)絕緣擊穿故障。電氣設備局部放電發(fā)生的原因多種多樣，如絕緣設計不合理，絕緣材料中存在雜質、氣泡或裂紋，電極表面粗糙或因劃傷而引發(fā)的尖刺，設備裝配中的偏差，設備運輸或試驗過程中帶來的各類損傷，設備在運行過程中因震動而導致的連接部件的松動，以及絕緣的老化等，這些因素均會導致設備內部電場應力集中而引發(fā)局部放電。局部放電本身并不等同于絕緣故障，一般可以在電氣設備運行過程中存在相當長的時間。局部放電的發(fā)生、發(fā)展及其破壞作用具有很大的隨機性，并因絕緣材料、絕緣結構、運行工況以及周圍環(huán)境等眾多因素的不同而不同，這也使得局部放電狀態(tài)及危害程度的評估十分復雜。國際上最早提出局部放電這一概念是20 世紀初，到20 世紀80 年代就已經(jīng)建立了國際公認的測量標準（IEC 270）。長期以來局部放電現(xiàn)象一直受到人們的高度重視，局部放電測量被廣泛應用于高壓設備的型式試驗、出廠試驗、交接試驗以及絕緣預防性試驗，成為檢驗設備質量工藝水平及絕緣性能的關鍵參數(shù)，同時也是反映高壓設備早期絕緣缺陷最靈敏和最有效的指標。多年以來，人們也一直致力于將局部放電檢測應用于設備的帶電測試，然而由于局部放電帶電檢測情況下的靈敏度、高壓設備工作現(xiàn)場復雜的電磁干擾等技術瓶頸的制約，局部放電帶電檢測和在線監(jiān)測技術的發(fā)展非常緩慢。自1986 年英國Strathclyde 大學在蘇格蘭的Torness 核電站安裝了第一套氣體絕緣金屬封閉開關設備（GIS）的局部放電特高頻監(jiān)測裝置以來，局部放電特高頻檢測技術日益成為該領域研究的熱點，發(fā)表的論文不下數(shù)百篇。特高頻法（ultra-high frequency，300MHz～3GHz）就是利用GIS 局部放電輻射出的特高頻電磁波信號進行檢測的一種方法。研究表明，GIS 局部放電將會產(chǎn)生很陡的脈沖電流，并向四周輻射多種頻率的電磁波，通過特高頻傳感器接收其中300MHz～3GHz 的電磁波信號，可實現(xiàn)對局部放電的檢測和定位。由于特高頻法具有抗干擾能力強、靈敏度高等特點，而且這種非接觸式的測量方式對于二次設備和檢測人員而言都更安全，系統(tǒng)結構簡單，特別適合于在線監(jiān)測，因而較之于其他檢測方法具有明顯的優(yōu)勢。局部放電特高頻在線檢測技術的應用則隨著北京2008 奧運會的舉辦而掀起了高潮，也正是自2008 年起，國家電網(wǎng)公司陸續(xù)發(fā)布了十余項規(guī)范輸變電設備狀態(tài)檢修的企業(yè)標準，廣東電網(wǎng)公司則于2009 年底首次啟動了GIS 局部放電特高頻在線監(jiān)測系統(tǒng)的大規(guī)模招標采購。在國家電網(wǎng)公司十二五規(guī)劃中，智能電網(wǎng)建設引領能源產(chǎn)業(yè)發(fā)展的引擎，智能設備及狀態(tài)評估均離不開在線檢測技術的支撐，局部放電特高頻檢測技術赫然在列。然而，在局部放電特高頻在線檢測技術迅速發(fā)展的過程中，也暴露出一系列的問題：（1）相關技術標準、規(guī)范不健全，缺乏統(tǒng)一有效的指導；（2）設備運行現(xiàn)場復雜的放電類干擾依然嚴重影響特高頻檢測的應用；（3）特高頻局部放電檢測技術在故障診斷和狀態(tài)評估的理論和應用均不完善；（4）特高頻局部放電檢測技術本身應用的瓶頸較高，難度較大。這些問題導致人們一度對局部放電特高頻檢測技術存在很大爭議，令現(xiàn)場從事運檢工作的技術人員感到困惑。廣東電網(wǎng)公司電力科學研究院（簡稱廣東電科院）從20 世紀90 年代末期開始至今，一直持續(xù)進行局部放電特高頻檢測技術研究和工程應用，近年來開展了GIS 標準化相關的一系列關鍵技術研究，首次提出并建立了國內外首個GIS 全尺寸標定平臺、開發(fā)了現(xiàn)場靈敏度校核系統(tǒng)，技術成果全面應用于廣東電網(wǎng)公司GIS 生命周期管理，極大地提高了GIS的運行可靠性，2012 年實現(xiàn)GIS 事故率同比下降54%。本書基于廣東電科院近年來在GIS 局部放電特高頻檢測技術取得的應用成果，參考國內外相關著作和文獻編著而成，在此向相關著作和文獻的作者表示衷心的感謝。本書在編寫過程中得到了華北電力大學高壓教研室?guī)熒拇罅χС郑{了鄭書生、詹花茂、王彩雄、魏振等各位老師和博士的研究資料及成果，全書得到了李成榕教授的悉心指導。在此向華北電力大學各位老師和學生一并表示感謝！由于學識水平有限，成書倉促，不當之處敬請諒解，并請不吝批評指正！編著者2016 年5 月
前言
1 概述··············································································································1
1.1國內外狀態(tài)檢修背景簡介······································································1
1.2局部放電檢測技術··················································································4
1.3局部放電特高頻在線檢測技術······························································6
1.4局部放電特高頻檢測技術的主要內容················································12
2局部放電理論·····························································································14
2.1局部放電的概念···················································································14
2.2局部放電的物理過程············································································15
2.3局部放電的基本參數(shù)············································································24
2.4局部放電輻射原理················································································26
2.5常規(guī)局部放電與特高頻局部放電信號之間的關系·····························30
3局部放電特高頻電磁波在GIS中的傳播特性·········································33
3.1波導理論·······························································································33
3.2 GIS中電磁波傳播規(guī)律仿真·································································34
3.3 GIS結構對電磁波傳播的影響·····························································43
3.4 GIS中局部放電特高頻電磁波傳播特性的試驗研究··························47
4局部放電特高頻檢測技術基礎··································································58
4.1天線接收原理·······················································································58
4.2局部放電特高頻檢測系統(tǒng)····································································59
4.3局部放電特高頻信號的時頻特征························································62
4.4局部放電特高頻檢測的抗干擾技術····················································64
4.5局部放電特高頻檢測的模式識別························································78
5局部放電特高頻檢測的標定·····································································92
5.1時域參考法測量原理············································································93
5.2局部放電特高頻檢測性能的關鍵指標·················································96
5.3基于GTEM小室的局部放電特高頻標定方法····································99
5.4 GIS局部放電標定結果的檢驗···························································102
6局部放電特高頻定位技術·······································································105
6.1 GIS局部放電特高頻定位常用的方法···············································105
6.2時間差定位方法··················································································107
7特高頻檢測技術在GIS局部放電狀態(tài)監(jiān)測中的應用····························121
7.1概述·····································································································121
7.2 GIS局部放電特高頻檢測技術的應用···············································123
7.3 GIS局部放電特高頻檢測典型案例分析···········································126
參考文獻··············································································································182
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