气体绝缘变压器局部放电超高频在线监测系统

　高电压技术　第36卷第7期2010年7月31日

High Voltage Engineering ,Vol.36,No.7,J uly 31,2010

气体绝缘变压器局部放电超高频在线监测系统

张晓星1,王　震1,唐　炬1,刘　蕾2,魏　燕2

(1.重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030;

2.重庆市电力公司城区供电局,重庆400010)

摘　要:SF 6气体绝缘变压器(GIT )在城市电网中得到广泛应用,建立GIT 局部放电在线监测系统,对准确掌握设备内部绝缘运行状态和指导检修具有重要意义。为此根据现场GIT 的结构和运行特点,设计了适用于现场局部放电检测的外置超高频微带贴片天线(MPA )传感器。采用选择天线基板材料、附加阻抗匹配和多调谐回路等频带展宽技术,设计的天线有效工作频带为340～440M Hz (驻波比<2),相对带宽2516%,最大增益达到5138dB 。MPA 传感器安装在电缆进线侧、风机管道处、110kV 侧及10kV 侧散热管处的GIT 绝缘子上,构建了GIT 局部放电在

线监测系统,开发了基于#

C 的监测系统软件。通过重庆市新民街GIT 变电站运行,运行结果表明,研制的在线检测系统能实现GIT 现场的局部放电信号的长期在线监测,为GIT 的状态检修提供了大量的可靠数据。关键词:SF 6;气体绝缘变压器;微带贴片天线;局部放电;超高频;在线检测中图分类号:TM835文献标志码:A 文章编号:100326520(2010)0721692206

基金资助项目:国家重点基础研究发展计划(973计划)

(2009CB724506);国家自然科学基金(50977095)。

Project Supported by National Basic Research Program of China (973Program )(2009CB724506),National Natural Science Founda 2tion of China (50977095).

GIT Partial Discharge UHF On 2line Monitoring System

ZHAN G Xiao 2xing 1,WAN G Zhen 1,TAN G J u 1,L IU Lei 2,WEI Yan 2

(1.State Key Laboratory of Power Transmission Equip ment &System Security and New Technology ,

Chongqing University ,Chongqing 400030,China ;

2.Chengqu Bureau of Chongqing Electric Power Company ,Chongqing 400010,China )

Abstract :According to the structure and operating characteristic of gas insulated transformer (GIT ),an outer ultra high f requency (U HF )microstrip patch antenna (MPA )sensor was designed suitable for detecting the partial dis 2charge on site.Some effective methods for expanding bandwidth are utilized in the design process ,such as choosing the material ,adding impedance matching and multi -tuning loop.The effective working bandwidth of the antenna is 340～440M Hz ,and the relative bandwidth is 25.6%,at the same time ,the maximal gain reaches 5.38dBi.MPA sensors were installed on the GIT insulators ,which were located in the cable section of incoming line ,fan duct ,cooling pipe of 110kV and 10kV side.Then online monitoring system for GIT was structured and detecting system software based on

#

C was developed.Through the operation of GIT substation in Xinmin street of Chongqing City ,

the results show that the online monitoring system developed can detect U HF GIT PD signal for a long time ,which have provided lots of reliable data for condition 2based maintenance.

K ey w ords :SF 6;gas insulated transformer (GIT );microstrip patch antenna (MPA );partial discharge (PD );ultra high f requency (U HF );on 2line monitoring

0　引言

SF 6气体绝缘变压器(gas insulated t ransform 2er ,GIT )是一种不燃不爆的环保型变压器,它不仅

克服了油浸变压器易燃、运行不安全的缺点,还克服了干式变压器容量小的缺点,因此,GIT 在地下变电站和场地狭窄、人口密集、防火要求高的市区等场所的使用日益广泛[1,2]。目前,国内使用GIT 的城

市有:北京、深圳、重庆、广州和香港等地,均已取得

了较好的社会和经济效益。

GIT 的结构原则上与油浸式变压器相同,其结构与设计上的特点主要在于绝缘和散热冷却两个方面:GIT 的主绝缘结构,即铁心与线圈、线圈与线圈之间采用纸筒和SF 6气隙(由层压纸板撑条隔开纸板的空道)组成。GIT 一、二次侧绕组间、绕组对地之间的主绝缘的绝缘强度主要决定于SF 6气体的绝缘强度。为增强绝缘和散热性能,采用提高SF 6气体压力方式,但也不能因采用过高的压力,而增加箱体的设计制造难度。一般小型变压器采用011M Pa 的压力,中型变压器采用约0114M Pa 的压力,大型的变压器应选择更高的压力。由于SF 6气体

2

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