《局部放电检测原理》PPT课件

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1、ReviewofLecture51.MechanismsofDielectricAgingbyPD2.ProcessofDielectricAgingbyPD3.TheInfluenceFactorsonAgingRate4.PDEvaluationApproachesContents:Electricalagingisatypeofdielectricdeteriorationunderthelong-termelectricalfieldandduetothefactofpartialdischarges.DefinitionofElectrical

2、Aging:1ReviewofLecture5Damageofinternaldischargetopolymerandoil-paperbranchedtypebrushtypetree2ReviewofLecture5TheInfluenceFactorsonAgingRateElectricalfieldstressVoltagefrequencySituationofcavityandgascontentsinsideTemperatureandhumidityMechanicalforce3ReviewofLecture5Estimationb

3、ythebasicparameters(1)Apparentcharge,qa(2)Dischargeenergyandpower,WandP(3)Thephaseangleofpulses(4)UiandUeEstimationbythedistribution(statistical)graphs4Lecture6PrinciplesofElectricalDischargeDetection局部放电检测的基本原理5Contents1.TheBasicDiagramofERA2.TheDetectionImpedance3.TheAmplificat

4、ionofImpulses4.DetectionSensitivity5.ImpulseResolution6.Calibration脉冲电流法基本原理检测阻抗脉冲放大检测灵敏度脉冲分辨率放电量标定61.TheBasicDiagramofERA1.Ahigh-voltagesourcee,freeofdischarge.2.Asamplecxaffectedbydischarges.3.AnimpedanceZd4.AcouplingcapacitanceCk6.AnamplifierA7.AnobservationunitO高压电源，无局放试品检测阻抗

5、耦合电容放大器观测单元Δu5.AprotectingimpedanceZm保护阻抗，低通滤波71.TheBasicDiagramofERATwoconnectingmethods(thelocationofZdincircuit):1.InserieswiththesampleCx-Seriescircuit.2.InserieswiththecouplingcapacitorCk-Parallelcircuit.SeriescircuitParallelcircuit串联回路并联回路82.TheDetectionImpedanceFunctions:(

6、1)totransfertheimpulsecurrentintovoltageand(2)tosuppresstheinterferencesofpowerfrequencyandharmonicfromsource.RCcircuitRLCcircuit取得局部放电所产生的高频脉冲信号抑制试验电压的工频及其谐波的低频信号92.1theRCcircuit2.TheDetectionImpedanceDischargeextinguishes,CddischargesviaRdCt，Tunedcapacitance调谐电容Dampingconstant衰

7、减常数102.TheDetectionImpedanceFrequencyspectrumofRCcircuitIfconsideringtherisingedgeofimpulseFT3dB11(1)Theheightoftheimpulseisproportionaltothemagnitudeqofthedischarges.(2)Cd↘→Δudm↗→sensitivity↗.检测阻抗上的脉冲高度与放电量q成正比一定的q下，减小Cd可以增大Δudm,提高灵敏度(3)AcouplingcapacitanceCkisneeded,substitutin

8、garbitrarycapacitanceforCkresultsinavery