干式SF6气体绝缘换流变压器阀省略电流致热型放电故障分析及现场修复周安春

425Vol.42No.520185PowerSystemTechnologyMay20181000-3673201805-1401-09TM85A470·40SF6周安春1，高理迎1，冀肖彤1，张民1，汤浩2（1．国家电网有限公司，北京市西城区100031；2．中国电力科学研究院有限公司，北京市海淀区100192）AnalysisandField-RepairofCurrentOverheatingFaultsonDryTypeSF6Gas-InsulatedValveSideBushinginConverterTransformerZHOUAnchun1,GAOLiying1,JIXiaotong1,ZHANGMin1,TANGHao2(1.StateGridCorporationofChina,XichengDistrict,Beijing100031,China;2.ChinaElectricPowerResearchInstitute,HaidianDistrict,Beijing100192,China)1ABSTRACT:Inordertoanalyzeanddiagnoseinternaldischargefailureoftwo±500kVSF6gas-insulatedvalvesidebushingsinconvertertransformers,insulationcharacteristicsbeforeandafterthedischargeandinternalcharacteristicsafterdisassemblyaretestedandchecked.Temperaturedistributionofcurrent-carryingconductorandinsulatoraresimulatedwithfiniteelementmethod.DCresistanceofconductor,contentofSF6decompositionproducts,temperaturecalculationresults,overheatinganddischargetracesshowthatbushingdischargefailuresinYiminandBaojiconvertorstationarecausedbycontactresistanceabnormalheatingoftransitionalcopper-aluminumcontactinconductivetubeandcontaminationofnylonguideconedecompositionalongSF6/epoxyinsulationinterface.AccordingtoIEChottestspottemperaturestandardandfaultbushingtemperaturefieldcalculationresults,anewdiagnosticcriteriaofinternalheatingdefectswithtemperaturedifferenceof25betweenthehottestpointandambienttemperatureareputforward.Andthismethodisverifiedbyabushingofthesametypewithabnormalthermaldefect.75bushingsofthesametypearerepairedon-sitewithoutshiftingconvertertransformersandremovingthedefectivebushings.TheresultsprovideamethodandbasisfordiagnosisandmanagementofheatingdefectsinSF6gas-insulatedhighvoltagebushings.KEYWORDS:SF6gasinsulation;convertertransformervalve-sidebushing;bushingdischargefailure;currentoverheating;fieldrepair±500kVSF6(GYB17201400058)ProjectSupportedbyScienceandTechnologyProjectofSGCC(GYB17201400058).SF6SF6/IEC25375SF6SF6DOI10.13335/j.1000-3673.pst.2018.02190()[1-6][7-11]1402SF6Vol.42No.5SF6/SF6SF6[12-15][16-17]IEC60137InsulatedBushingsforAlternatingVoltagesAbove1000VSF6SF6[18-20]±500kVSF6Tr=25GSETF1950/536-3150ACspezSF6751500kVSF6HSPSF611Fig.1SchematicdiagramofthefaultvalvesidebushinginconvertertransformerMCCUD22.1±500kV20126280623P1PPRBAI±500kV20174160104IIABX4251403IIIY/YBIIY/YB22Fig.2LocationofthefailurevalvesidebushingsofconvertertransformerinYiminandBaojiconvertorStation2.2IY/YB11Tab.1TestdataofthebushingbeforeandafterthefailureinYiminconvertorstation/MΩ≥100001000044.7/pF1200±5%12010.1/%≤0.70.3424H2S/(μL/L)≤20100SO2/(μL/L)≤20111DL/T39320101IY/YBSF6H2SSO2IIY/YBSF6150μL/LSO233.133Fig.3Disintegrationprocessofthefaultbushing1404SF6Vol.42No.53.2SF622Tab.2TestdataofthebushingsbeforedisintegrationinYiminandBaojiconvertorstationSO2/(μL/L)≤2111150H2S/(μL/L)≤21000Rdc/μΩ4080010002SF6SF64032454522SF63.3262MC2/SF624Fig.4Disintegrationphotosofconductivetubecopperandaluminiumtransitionzoneinfailurebushings5Fig.5Flashoverdischargepathonthesurfaceoffailurebushings’capacitivecores44.1SF6(GSETF1950/536-3150ACspez)Comsol42514056Fig.6Dischargepathoffailurebushings3Y/Y3Tab.3Calculatedresistancelossofdifferentbushingconductorrelatedwiththecurrentspectrumh/HzIh/AP0h/W(Rc:0μΩ)P1h/W(Rc:98μΩ)P2h/W(Rc:200μΩ)P3h/W(Rc:500μΩ)1502337.7383.91074.92193.85484.45250424.727.376.5156.1390.37350272.013.337.175.8189.411550119.53.29.018.345.81365078.41.54.28.621.41785040.40.51.32.66.51995031.00.30.81.64.123115024.00.20.51.12.725125021.90.20.50.92.329145017.70.10.30.71.631155014.90.10.20.51.235175011.00.00.10.30.73718509.60.00.10.20.54120508.00.00.10.20.44321507.70.00.10.20.44723506.90.00.10.10.34924506.20.00.10.10.3430.71205.92461.06152.5P0hP1hP2hP3h098200500μΩh30μΩ(35)h15749P0430.798200500μΩP1P2P31205.92461.06152.5WP0+0P0+P1P0+P2P0+P398μΩ200μΩ500μΩ703077Fig.7Temperaturedistributionunderdifferentcontactresistanceofcasingcopperandaluminiumtransitionzone76ABCD88Rc098200500800μΩ781(Rc0μΩ)1406060120180240//01203602404806007208Fig.8Inaluminumtr2200823119254500μΩ430(a)(b)02000042000nsideandoutsidransitionzonew30(SF6120SF64000040006000/detemperaturwithdifferent011889K55260119()IEC6000800010000Rc=0μΩRc=98μΩRc=200μΩRc=500μΩRc=800μΩRc=0μΩRc=98μΩRc=200μΩRc=500μΩRc=800μΩ/mm/mmreofcopperancontactresista98Rc200Rc98)Rc98μΩ60137ndance0μΩ8μΩRcGSE4.224.9Fi3536IEC98μΩETF1950/5320159IIY/YGSET99ig.9Infraredvalve-sideb9Tr(25)20159()3MC20159Tr(256-3150ACspTr=26-3150ACs19YATF1950/536-350.2dspectrumoftbushingwitha20337μ19)pezSF625spezSF63150ACspe9theconverterabnormaltemp24.9μΩ(GS6Vol.42No.56(z)1/325.3transformerperatureIIY/YAIIY/YA35μΩ)SETF1950/3/425140755.1±500kVHSP1010Fig.10Field-repairdevicefordefectivebushingconductivetube10115.21SF61000Pa50Pa0.02MPa2311Fig.11Fixtureplatformofon-siterepairdevice455mm/sMC5000N671/381000N950PaSF61024hSF6SF6DL/T3932017±500kV57512DL/T393DL/T5961408Fig.1SF64Tab.4Testbushin/M/pSF6/(μLH2SSO215061212InstallatioABCresultsofthengsafterthefiMΩ/MΩpF/%/%L/L)S/(μL/L2(μL/L)7515751.1SF6nofnewcondu46convertertraneldrepairinB≥1≥120≤)1uctivetubeInsformervalve-Baojistation1000