Treść książki
Przejdź do opcji czytnikaPrzejdź do nawigacjiPrzejdź do informacjiPrzejdź do stopki
INTERNALPHOTO-EFFECTINMATERIALS
FORHIGH-VOLTAGEOUT-DOORINSULATION
RyszardKACPRZYK,WitoldBRETUJ
PolitechnikaWrocławska
WydziałElektryczny,KatedraPodstawElektrotechnikiiElektrotechnologii
Mostofdielectricsoperatingintheroomtemperatureregionusetoexhibit
anactivationcharacterofconductivity.Activationenergyoftheconduction
processisusuallyonthelevelofWa=0.5-2.5eV.Incaseofoutdoor
insulation,exposedtoastrongirradiationbywhitelightandUV(sun-light)
onecanexpectalight-generationofadditionalconcentrationofcharge
carriers,especiallyforirradiationinUVregionwithquantenergyE>3.0eV.
Generationofadditionalchargecarriersleadsfinallytoanincreaseof
surfaceconductionoftheinsulatingmaterial.Incaseofinsulatingsystems
operatinginacfields,ac-voltagedistributionalongtheinsulatoris
determinedbycapacitancedistributionofparticularpartsoftheinsulating
systemand(forhighsurfaceresistivitydielectrics)doesnotdependon
resistivitydistribution.Incaseofinsulatingsystemoperatingindcfields,
potentialdistributionisdeterminedbyresistancedistribution,whichcanbe
influencedbytheinternalphoto-effect.Resultsofinvestigationoftheinternal
photo-effect,appearingondielectricsappliedinconstructionofoutdoor
insulatingsystems,werepresentedinthepaper.Investigationsofsurface
resistivitycarriedoutonsamples(orinsulators)madeofglass,ceramicsand
compositeinsulatorscoveredbysiliconlayersconfirmedsurfaceresistivity
decreaseforsamplessubmittedtoirradiationbywhiteandUV
light
(radiationlength0.3-0.8micro-meter)withintensityofabout5000lx.After
irradiationa1.5
upto10timesdecreaseofsurfaceresistivity
was
registered,withtheleveldependingontheparticulardielectric.Discussion
ofpossibleinfluenceoftheinvestigatedphenomenonontheconstructionof
insulatingsystemsoperatingindcfieldswasalsogiven,especiallyinthe
areaofphoto-effectinfluenceonpotentialdistributionalongtheinsulator.
Keywords:insulatingmaterials,potentialdistribution,internalphoto-effect
8
