基于信號時頻分析的絕緣熱老化局部放電試驗研究.pdf

1、長沙理工大學(xué)碩士學(xué)位論文基于信號時頻分析的絕緣熱老化局部放電試驗研究姓名：張婷婷申請學(xué)位級別：碩士專業(yè)：電力系統(tǒng)及其自動化指導(dǎo)教師：向洋20080401ABSTRACTAgingphenonenonisalwaysanimportancestudyitemininsulationsubjectAfterinsulationdiagnosisandlifetimepredictiononelectronicdevices，therewil

2、lbegreatlybenefitialtoelectronicsystemandeconomicperformanceMeanwhile，alotofinsulationdiagnosissystemswhichareadvanced，convenientandreliablewasformedAsakindofinsulationmaterial，epoxyresiniswidelyusedinelectricandelectron

3、icdevicesanditsinsulationpropertieswilldirectlyaffectsperformancesaftyandreliableofequipmentPartialdischargedetectionisaneffectivemeanswhichisusedinhigh—voltageelectricalequipmentinsulationdiagnosis，butPartialdischargesi

4、gnalisnonstablesignalanditsfrequencymaychangewithtimewhile，needtousethejointtime—frequencyanalysiswhithisapracticaltooltoanalyzeanddealwithnonstabletime—changesignalForthesereasons，theresearchusedsamplesmadeofepoxyresin，

5、designedanagingboxspecially80“Cand120℃wereselectedforthetemperaturetoacceleratetheagingoftheagingtwobatchesofsamples，8hagingcycleforatotaloffouragingcycleAftereachagingcycle，wemeasuredandrecordeddataofpartialdischargesig

6、nal，meanwhileusedjointtimefrequencyanalysismethodtogetcharacteristicsofdischargesignal，asagingtimechanging，judgedpartialdischargechangesaswellasdistinctionunderbothtemperaturesandaginginsulationsampleStudyshowsthattime—f

7、requencyanalysistechniquewasappliedtoanalysisandmanagementofpartialdischargesignal，whichcouldclearlyrevealthechangingprocessontimefrequencyplaneofpartialdischargesignalanddemostratetimevaryingcharacteristicsofpartialdisc

8、hargesignalaccuratelyMoreover，itbecomesmoresimplerandmoreintuitiveTheresearchprovidesamoreaccurateandreliablemethodtecognizepartialdischargesignal’Spattern。Itcanbeseenfromanalysisresults：indifferentstagesofaging，partiald

9、ischargefrequencycharacteristicsignificantly，andwiththeagingtimeincreasing，inthelowfrequencyregioncontinuedtodischargeandchangesinsmall，buthigh—frequencyspectrumregioncharacteristicpeak，andwiththeaginglengthentheduration