谐波对变压器绝缘老化的影响分析-豆柴文库

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谐波对变压器绝缘老化的影响分析
Title:AnalysisoftheEffectsofHarmonicsonInsulationAginginTransformers
Introduction:
Inelectricalpowersystems,transformersplayavitalroleinfacilitatingthetransmissionanddistributionofelectricalenergy.However,transformersaresubjectedtovariouselectricalandthermalstressorsthatcanleadtoinsulationagingandsubsequentdegradation.Onesuchstressoristhepresenceofharmonicsinthepowersystem.Thispaperaimstoinvestigatetheeffectsofharmonicsoninsulationagingintransformers.
1.UnderstandingHarmonics:
Harmonicsaresinusoidalvoltagesorcurrentsthathavefrequenciesthatareintegermultiplesofthefundamentalfrequency.Theyaretypicallycausedbynonlinearloadssuchasrectifiers,powerelectronics,andarcfurnaces.Harmoniccurrentscanflowthroughthetransformerwindingsandgenerateadditionallossesandheating,potentiallyacceleratingtheagingofinsulationmaterials.
2.InsulationAgingMechanisms:
Insulationagingintransformerscanoccurduetoacombinationoffactors,includingthermal,electrical,andchemicalstresses.Theprimaryinsulationmaterialsusedintransformersaretypicallymineraloilandpaper.Thermalagingisprimarilycausedbyoverloadconditionsandleadstothereductionofinsulationlife.Electricalagingiscausedbyelectricaldischargeswithintheinsulationmaterial,resultingfromvoltagestressandthepresenceofpartialdischarge(PD)activity.Chemicalagingreferstothedegradationofinsulationmaterialsduetochemicalreactionswithcontaminantsorwithby-productsgeneratedduringthermalandelectricalagingprocesses.
3.EffectofHarmonicsonInsulationAging:
3.1AdditionalLossesandHeating:
Harmoniccurrentsflowingthroughthewindingsinduceadditionalresistivelossesduetoskineffectandproximityeffect.Theseadditionallossesleadtoincreasedtemperatureriseandcanacceleratetheagingprocessoftheinsulationmaterials,particularlythepaperinsulation.
3.2IncreaseinVoltageStress:
Harmonicscanincreasetheeffectivevoltagestressontheinsulation,leadingtoincreasedPDactivity.PDactivity,ifleftuncontrolled,cancauseinsulationbreakdownandfurtheraccelerateaging.
3.3InfluenceonTransformerCooling: