Qee cov khoom siv hauv cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob muaj cov khoom siv hluav taws xob, uas yog, lawv muaj qhov ua haujlwm siab rau tam sim no. Qhov peev xwm no tso cai rau lawv tsis dhau tam sim no, thiab yog li ntawd lawv tau siv los tsim cov rwb thaiv tsev rau cov khoom nqa tam sim no. Cov khoom siv hluav taws xob insulating yog tsim los tsis tsuas yog cais cov khoom nqa tam sim no, tab sis kuj tsim kev tiv thaiv kev phom sij ntawm hluav taws xob tam sim no. Piv txwv li, cov hlua hluav taws xob ntawm cov khoom siv hluav taws xob tau them nrog rwb thaiv tsev.
Cov khoom siv hluav taws xob hluav taws xob thiab lawv cov ntawv thov
Cov khoom siv hluav taws xob hluav taws xob tau siv dav hauv kev lag luam, xov tooj cua thiab ntsuas kev tsim, thiab kev tsim hluav taws xob sib txuas. Kev ua haujlwm ib txwm muaj ntawm cov khoom siv hluav taws xob lossis kev nyab xeeb ntawm lub zog hluav taws xob hluav taws xob feem ntau nyob ntawmsiv dielectrics. Qee qhov tsis zoo ntawm cov khoom siv rau kev rwb thaiv tsev hluav taws xob txiav txim siab nws qhov zoo thiab muaj peev xwm.
Kev siv cov ntaub ntawv insulating yog ua raws li cov cai tswj kev nyab xeeb. Kev ncaj ncees ntawm cov rwb thaiv tsev yog tus yuam sij rau kev nyab xeeb ua haujlwm nrog hluav taws xob tam sim no. Nws yog qhov txaus ntshai heev los siv cov khoom siv nrog cov rwb thaiv tsev puas. Txawm tias muaj hluav taws xob me ntsis tuaj yeem cuam tshuam rau tib neeg lub cev.
Properties of dielectrics
Cov khoom siv hluav taws xob hluav taws xob yuav tsum muaj qee yam khoom txhawm rau ua lawv txoj haujlwm. Lub ntsiab sib txawv ntawm dielectrics thiab conductors yog lub ntim loj resistivity (109-1020 ohm cm). Qhov hluav taws xob conductivity ntawm conductors piv nrog dielectrics yog 15 npaug ntau dua. Qhov no yog vim qhov tseeb tias insulators los ntawm lawv qhov xwm txheej muaj ob peb zaug tsawg dua ions dawb thiab electrons, uas muab cov khoom siv tam sim no. Tab sis thaum cov khoom siv rhuab, muaj ntau ntawm lawv, uas ua rau muaj kev nce hauv hluav taws xob conductivity.
Sib txawv ntawm cov khoom nquag thiab tsis muaj zog ntawm dielectrics. Rau cov ntaub ntawv insulating, cov khoom passive yog qhov tseem ceeb tshaj plaws. Lub dielectric qhov tsis tu ncua ntawm cov khoom yuav tsum tsawg li tsawg tau. Qhov no tso cai rau lub isolator tsis qhia cov kab mob parasitic rau hauv Circuit Court. Rau cov khoom siv raws li dielectric ntawm lub capacitor, qhov dielectric tas li yuav tsum, ntawm qhov tsis sib xws, loj npaum li qhov ua tau.
Insulation xaiv
Rau qhov tsis tseem ceebhluav taws xob rwb thaiv tsev muaj xws li hluav taws xob lub zog, hluav taws xob resistivity, txheeb ze permittivity, dielectric poob lub kaum sab xis. Thaum ntsuas qhov hluav taws xob insulating cov khoom ntawm cov khoom, qhov kev cia siab ntawm cov yam ntxwv ntawm cov npe ntawm qhov loj ntawm cov hluav taws xob tam sim no thiab qhov hluav taws xob kuj raug coj mus rau hauv tus account.
Cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob muaj lub zog hluav taws xob ntau dua piv nrog cov conductors thiab semiconductors. Kuj tseem ceeb rau lub dielectric yog qhov ruaj khov ntawm cov txiaj ntsig tshwj xeeb thaum lub sijhawm cua sov, qhov hluav taws xob nce thiab lwm yam kev hloov pauv.
Kev faib tawm cov khoom siv dielectric
Raws li lub zog ntawm qhov tam sim no dhau los ntawm tus neeg xyuas pib, ntau hom rwb thaiv tsev siv, uas txawv ntawm lawv qhov peev xwm.
Raws li qhov ntsuas dab tsi yog cov khoom siv hluav taws xob insulating faib? Kev faib tawm ntawm dielectrics yog nyob ntawm lawv lub xeev ntawm kev sib sau (khoom, kua thiab gaseous) thiab keeb kwm (organic: ntuj thiab hluavtaws, inorganic: ntuj thiab dag). Feem ntau hom khoom dielectric, uas tuaj yeem pom ntawm cov hlua ntawm cov khoom siv hauv tsev lossis lwm yam khoom siv hluav taws xob.
Khoom thiab kua dielectrics, nyob rau hauv lem, muab faib ua subgroups. Khoom dielectrics muaj xws li cov ntaub ntawv varnished, laminates thiab ntau hom mica. Waxes, roj thiab liquefied gases yog kua hluav taws xob insulating cov ntaub ntawv. Tshwj xeeb gaseous dielectrics yog siv ntau tsawg zaus. Hom no kuj suav nroglub ntuj hluav taws xob insulator yog cua. Nws siv yog vim tsis tsuas yog cov yam ntxwv ntawm huab cua, uas ua rau nws ib tug zoo heev dielectric, tab sis kuj rau nws kev lag luam. Kev siv huab cua li rwb thaiv tsev tsis xav tau cov khoom siv ntxiv.
Solid Dielectrics
Khoom siv hluav taws xob insulating yog cov chav kawm dav tshaj plaws ntawm dielectrics uas tau siv ntau yam. Lawv muaj cov tshuaj sib txawv, thiab cov dielectric tas li ntawm 1 txog 50,000.
Khoom dielectrics muab faib ua cov tsis-polar, polar thiab ferroelectrics. Lawv qhov sib txawv tseem ceeb yog nyob rau hauv cov txheej txheem ntawm polarization. Cov chav kawm ntawm rwb thaiv tsev no muaj cov khoom xws li tshuaj tiv thaiv, taug qab tsis kam, dendritic tsis kam. Tshuaj tiv thaiv yog qhia nyob rau hauv lub peev xwm los tiv thaiv kev cuam tshuam ntawm ntau yam nruj ib puag ncig (acid, alkali, thiab lwm yam). Tracing kuj txiav txim siab lub peev xwm los tiv thaiv qhov cuam tshuam ntawm hluav taws xob arc, thiab dendritic tsis kam txiav txim qhov tsim ntawm dendrites.
Khoom dielectrics yog siv ntau yam ntawm lub zog. Piv txwv li, ceramic hluav taws xob insulating cov ntaub ntawv feem ntau yog siv los ua kab thiab bushing insulators hauv substations. Daim ntawv, polymers, fiberglass yog siv los ua rwb thaiv tsev rau cov khoom siv hluav taws xob. Rau cov cav tov thiab cov khoom siv, kua roj vanish, cardboard, compound feem ntau yog siv.
Rau siv ntau yam kev ua haujlwm, kev rwb thaiv tsev yog muab qee yam tshwj xeeb los ntawm kev sib txuas sib txawvcov ntaub ntawv: kub tsis kam, noo noo tsis kam, hluav taws xob tiv thaiv thiab Frost tsis kam. Thaum tshav kub kub-resistant insulators muaj peev xwm tiv taus kub txog 700 ° C, cov no muaj xws li iav thiab cov ntaub ntawv raws li lawv, organosilites thiab ib co polymers. Cov khoom siv dej-resistant thiab tropical-resistant yog fluoroplastic, uas tsis yog-hygroscopic thiab hydrophobic.
Radiation-resistant rwb thaiv tsev yog siv rau hauv cov khoom siv nrog cov ntsiab lus atomic. Nws suav nrog cov yeeb yaj kiab inorganic, qee hom polymers, fiberglass thiab mica-based cov ntaub ntawv. Frost-resistant yog cov rwb thaiv tsev uas tsis poob lawv cov khoom ntawm qhov kub txog -90 ° C. Cov kev cai tshwj xeeb yog muab tso rau ntawm rwb thaiv tsev rau cov khoom siv ua haujlwm hauv qhov chaw lossis lub tshuab nqus tsev. Rau cov hom phiaj no, cov khoom siv nqus tsev vacuum yog siv, uas suav nrog cov ceramics tshwj xeeb.
kua dielectrics
Cov khoom siv hluav taws xob ua kua hluav taws xob feem ntau siv hauv cov tshuab hluav taws xob thiab cov cuab yeej siv. Roj plays lub luag hauj lwm ntawm rwb thaiv tsev nyob rau hauv ib tug transformer. Cov kua dielectrics kuj suav nrog cov kua roj liquefied, cov roj tsis muaj vaseline thiab cov roj paraffin, polyorganosiloxanes, dej distilled (purified los ntawm ntsev thiab impurities).
Cov yam ntxwv tseem ceeb ntawm cov kua dielectric yog dielectric tas li, hluav taws xob muaj zog thiab hluav taws xob conductivity. Tsis tas li ntawd, qhov ntsuas hluav taws xob ntawm dielectrics feem ntau nyob ntawm seb lawv qhov kev ua kom huv. Khoom impurities tuaj yeem ua rau cov khoom siv hluav taws xob ntau ntxiv ntawm cov kua dej vim kev loj hlob ntawm cov ions dawb thiab hluav taws xob. Purification ntawm cov kua los ntawm distillation, ion pauv, thiab lwm yam. ua rau kom muaj zog ntawm cov khoom siv hluav taws xob, yog li txo nws cov hluav taws xob conductivity.
kua dielectrics muab faib ua peb pawg:
- roj av;
- zaub roj;
- synthetic fluids.
Cov roj siv feem ntau yog roj av xws li transformer, cable thiab capacitor roj. Synthetic fluids (organosilicon thiab organofluorine compounds) kuj tau siv hauv apparatus engineering. Piv txwv li, organosilicon tebchaw yog Frost-resistant thiab hygroscopic, yog li lawv yog siv los ua ib qho insulator nyob rau hauv me me transformers, tab sis lawv cov nqi yog siab tshaj tus nqi ntawm cov roj av.
Cov roj zaub tsis siv los ua cov khoom siv hluav taws xob hauv hluav taws xob insulating tshuab. Cov no muaj xws li castor, linseed, hemp thiab tung roj. Cov ntaub ntawv no tsis muaj zog polar dielectrics thiab feem ntau yog siv rau impregnating ntawv capacitors thiab ua cov yeeb yaj kiab-tsim tus neeg sawv cev hauv hluav taws xob insulating varnishes, xim, thiab enamels.
Gas dielectrics
Cov pa roj carbon monoxide feem ntau yog cua, nitrogen, hydrogen thiab SF6 roj. Hluav taws xob insulating gases muab faib ua tej yam ntuj tso thiab dag. Ntuj huab cua yog siv los ua rwb thaiv tsev ntawm cov khoom siv tam sim no ntawm cov kab hluav taws xob thiab cov tshuab hluav taws xob. Raws li ib qho insulator, huab cua muaj qhov tsis zoo uas ua rau nws tsis tuaj yeem siv nws hauv cov khoom siv kaw. Vim tias muaj cov pa oxygen siab, huab cua yog oxidizing tus neeg sawv cev, thiab hauv thaj chaw inhomogeneous, lub zog hluav taws xob tsawg ntawm huab cua tshwm.
Fais fab transformers thiab high-voltage cables siv nitrogen ua rwb thaiv tsev. Hydrogen, ntxiv rau ua cov khoom siv hluav taws xob, kuj tseem raug yuam kom txias, uas yog vim li cas nws feem ntau siv hauv cov tshuab hluav taws xob. Hauv kev sib dhos, SF6 feem ntau yog siv. Sau nrog SF6 roj ua rau cov cuab yeej tawg-pov thawj. Nws yog siv nyob rau hauv high-voltage Circuit Court breakers vim nws arc-extinguishing zog.
YOrganic dielectrics
Cov khoom siv organic dielectric muab faib ua ntuj thiab hluavtaws. Natural organic dielectrics tam sim no siv tsis tshua muaj heev, vim tias cov khoom siv hluavtaws tau nthuav dav ntau dua, yog li txo lawv cov nqi.
Rau cov organic dielectrics xws li cellulose, roj hmab, paraffin thiab zaub roj (cov roj castor). Feem ntau ntawm cov hluavtaws organic dielectrics yog ntau yam yas thiab elastomers feem ntau siv hauv cov khoom siv hluav taws xob hauv tsev thiab lwm yam khoom siv.
YInorganic dielectrics
Inorganic dielectric cov ntaub ntawv muab faib ua ntuj thiab dag. Feem ntau ntawm cov ntaub ntawv ntuj yog mica, uas muaj tshuaj lom neeg thiab thermal kuj. Phlogopite thiab muscovite kuj tseem siv rau hluav taws xob rwb thaiv tsev.
To dag inorganicdielectrics suav nrog iav thiab cov ntaub ntawv raws li nws, nrog rau cov plooj (porcelain) thiab ceramics. Nyob ntawm daim ntawv thov, cov khoom siv dag zog tuaj yeem muab cov khoom tshwj xeeb. Piv txwv li, feldspar ceramics yog siv rau bushings, uas muaj lub siab dielectric poob tangent.
Fibrous hluav taws xob insulating cov ntaub ntawv
cov ntaub ntawv Fibrous feem ntau yog siv rau rwb thaiv tsev hauv cov cuab yeej hluav taws xob thiab cov tshuab. Cov no suav nrog cov ntaub ntawv cog qoob loo (rubber, cellulose, fabrics), hluavtaws textiles (nylon, capron), nrog rau cov ntaub ntawv ua los ntawm polystyrene, polyamide, thiab lwm yam.
Cov ntaub ntawv organic fiber ntau yog hygroscopic heev, yog li lawv tsis tshua siv yam tsis muaj impregnation tshwj xeeb.
Tsis ntev los no, es tsis txhob siv cov khoom siv organic, hluavtaws fiber ntau rwb thaiv tsev tau siv, uas muaj qib siab dua ntawm cov cua sov. Cov no suav nrog iav fiber ntau thiab asbestos. Cov iav fiber ntau yog impregnated nrog ntau yam kua roj vanish thiab resins kom nws cov khoom siv hydrophobic. Asbestos fiber ntau muaj zog txhua yam, yog li paj rwb fiber ntau ntxiv rau nws.
