Qhov kev faib tawm ntawm lub zog hluav taws xob hauv cov cables AC yog sib xws, thiab qhov tsom mus rau cov ntaub ntawv rwb thaiv tsev cable yog nyob rau ntawm dielectric tas mus li, uas tsis cuam tshuam los ntawm qhov kub thiab txias. Qhov sib piv, qhov kev faib tawm ntawm kev ntxhov siab hauv DC cables yog qhov siab tshaj plaws ntawm txheej sab hauv ntawm cov rwb thaiv tsev thiab cuam tshuam los ntawm qhov tsis kam ntawm cov ntaub ntawv rwb thaiv tsev. Cov ntaub ntawv rwb thaiv tsev qhia txog qhov ntsuas kub tsis zoo, txhais tau tias thaum qhov kub nce ntxiv, qhov tsis kam txo qis.
Thaum ib lub cable ua haujlwm, qhov poob ntawm lub hauv paus ua rau qhov kub nce siab, ua rau muaj kev hloov pauv ntawm qhov resistivity ntawm cov khoom siv rwb thaiv tsev. Qhov no, ua rau lub zog hluav taws xob hauv cov txheej rwb thaiv tsev hloov pauv. Hauv lwm lo lus, rau tib lub thickness ntawm rwb thaiv tsev, qhov hluav taws xob tawg txo qis thaum qhov kub nce siab. Rau cov kab DC hauv cov chaw fais fab faib tawm, qhov kev laus ntawm cov khoom siv rwb thaiv tsev yog sai dua vim muaj kev hloov pauv ntawm qhov kub thiab txias piv rau cov cables faus, uas yog qhov tseem ceeb uas yuav tsum nco ntsoov.
Thaum lub sijhawm tsim cov txheej rwb thaiv tsev cable, cov khoom tsis huv yuav raug nkag mus. Cov khoom tsis huv no muaj qhov tsis kam tiv thaiv rwb thaiv tsev qis dua thiab faib tsis sib npaug raws li qhov kev taw qhia radial ntawm cov txheej rwb thaiv tsev. Qhov no ua rau muaj qhov tsis kam tiv thaiv ntim sib txawv ntawm ntau qhov chaw sib txawv. Hauv qab DC voltage, lub zog hluav taws xob hauv cov txheej rwb thaiv tsev kuj tseem yuav sib txawv, ua rau cov cheeb tsam uas muaj qhov tsis kam tiv thaiv ntim qis tshaj plaws laus sai dua thiab dhau los ua cov ntsiab lus tsis ua haujlwm.
Cov xov hluav taws xob AC tsis qhia txog qhov xwm txheej no. Hauv cov lus yooj yim, qhov kev ntxhov siab ntawm cov ntaub ntawv AC cable yog faib sib npaug, thaum nyob rau hauv DC cables, qhov kev ntxhov siab rwb thaiv tsev yeej ib txwm tsom mus rau qhov tsis muaj zog tshaj plaws. Yog li ntawd, cov txheej txheem tsim khoom thiab cov qauv rau AC thiab DC cables yuav tsum tau tswj hwm sib txawv.
Cov polyethylene txuas nrog (XLPE)Cov cables insulated siv dav hauv AC daim ntawv thov vim lawv cov dielectric zoo heev thiab lub cev muaj zog, nrog rau lawv cov nqi ua haujlwm siab. Txawm li cas los xij, thaum siv ua DC cables, lawv ntsib teeb meem loj ntsig txog qhov chaw them, uas yog qhov tseem ceeb tshwj xeeb hauv cov cables DC voltage siab. Thaum polymers siv ua DC cable rwb thaiv tsev, ntau qhov ntxiab hauv cov txheej rwb thaiv tsev ua rau muaj kev sib sau ua ke ntawm qhov chaw them. Qhov cuam tshuam ntawm qhov chaw them rau cov ntaub ntawv rwb thaiv tsev feem ntau pom hauv ob qho: kev cuam tshuam hluav taws xob thiab kev cuam tshuam tsis yog hluav taws xob, ob qho tib si ua rau cov khoom rwb thaiv tsev puas tsuaj heev.
Qhov chaw them nqi yog hais txog qhov them ntau dhau ntawm qhov tsis muaj hluav taws xob hauv ib chav tsev ntawm cov khoom siv macroscopic. Hauv cov khoom khov, qhov chaw them nqi zoo lossis tsis zoo raug khi rau cov qib zog hauv zos, muab cov teebmeem polarization hauv daim ntawv ntawm cov polarons khi. Qhov chaw them nqi polarization tshwm sim thaum cov ions dawb muaj nyob hauv cov khoom siv dielectric. Vim yog kev txav mus los ntawm ion, cov ions tsis zoo sib sau ua ke ntawm qhov interface ze ntawm lub electrode zoo, thiab cov ions zoo sib sau ua ke ntawm qhov interface ze ntawm lub electrode tsis zoo. Hauv lub tshav pob hluav taws xob AC, kev tsiv teb tsaws chaw ntawm cov nqi zoo thiab tsis zoo tsis tuaj yeem ua raws li kev hloov pauv sai hauv lub zog zaus hluav taws xob, yog li cov teebmeem them nqi chaw tsis tshwm sim. Hauv lub tshav pob hluav taws xob DC, txawm li cas los xij, lub tshav pob hluav taws xob faib raws li resistivity, ua rau muaj cov nqi chaw thiab cuam tshuam rau kev faib tawm ntawm lub tshav pob hluav taws xob. XLPE rwb thaiv tsev muaj ntau lub xeev hauv zos, ua rau cov teebmeem them nqi chaw tshwj xeeb heev.
Cov rwb thaiv tsev XLPE yog sib txuas ua ke los ntawm tshuaj lom neeg, tsim cov qauv sib txuas ua ke. Raws li cov polymer tsis yog polar, lub cable nws tus kheej tuaj yeem piv rau lub capacitor loj. Thaum DC kis tau nres, nws zoo ib yam li kev them lub capacitor. Txawm hais tias lub hauv paus ntawm tus neeg coj hluav taws xob tau grounded, kev tso tawm zoo tsis tshwm sim, tawm hauv qhov ntau ntawm lub zog DC khaws cia rau hauv lub cable ua qhov chaw them. Tsis zoo li AC fais fab cables, qhov twg qhov chaw them raug dissipated los ntawm dielectric poob, cov nqi no sau rau ntawm qhov tsis zoo hauv lub cable.
Raws li lub sijhawm dhau mus, nrog rau kev cuam tshuam hluav taws xob ntau zaus lossis kev hloov pauv ntawm lub zog tam sim no, XLPE insulated cables khaws cov nqi ntau dua thiab ntau qhov chaw, ua kom nrawm dua qhov laus ntawm cov txheej rwb thaiv tsev thiab txo cov kev pabcuam cable lub neej.
Lub sijhawm tshaj tawm: Lub Peb Hlis-10-2025