Lub tshuab hluav taws xob kev ntxhov siab nyob rau hauv AC cables yog ib yam, thiab lub hom phiaj ntawm cov ntaub ntawv rwb thaiv tsev yog nyob rau ntawm dielectric tas li, uas tsis cuam tshuam los ntawm qhov kub thiab txias. Nyob rau hauv sib piv, qhov kev nyuaj siab faib nyob rau hauv DC cables yog siab tshaj nyob rau hauv lub puab txheej ntawm rwb thaiv tsev thiab yog cuam tshuam los ntawm cov resistivity ntawm cov ntaub ntawv rwb thaiv tsev. Cov ntaub ntawv rwb thaiv tsev pom qhov tsis zoo kub coefficient, txhais tau hais tias thaum kub nce, resistivity txo.
Thaum lub cable ua haujlwm, cov tub ntxhais poob ua rau qhov kub thiab txias, ua rau muaj kev hloov pauv ntawm cov khoom siv rwb thaiv tsev. Qhov no, nyob rau hauv lem, ua rau hluav taws xob teb kev nyuaj siab nyob rau hauv lub rwb thaiv tsev txheej yuav txawv. Hauv lwm lo lus, rau tib lub thickness ntawm rwb thaiv tsev, qhov tawg voltage txo qis thaum kub nce. Rau DC lub cev cov kab hauv cov chaw nres tsheb fais fab, qhov kev laus ntawm cov khoom siv rwb thaiv tsev yog qhov nrawm dua vim qhov hloov pauv ntawm qhov kub thiab txias piv rau cov kab hluav taws xob faus, uas yog qhov tseem ceeb rau kev ceeb toom.
Thaum lub sij hawm tsim cov kab hluav taws xob rwb thaiv tsev txheej, impurities yog inevitably qhia. Cov impurities no muaj cov rwb thaiv tsev qis dua thiab tsis sib npaug ntawm cov kev taw qhia radial ntawm txheej rwb thaiv tsev. Qhov no ua rau txawv qhov ntim resistivity ntawm qhov chaw sib txawv. Nyob rau hauv DC voltage, hluav taws xob teb nyob rau hauv lub rwb thaiv tsev txheej kuj yuav sib txawv, ua rau cov cheeb tsam uas muaj qhov tsawg tshaj plaws ntim resistivity mus rau lub hnub nyoog sai dua thiab ua tej zaum cov ntsiab lus ntawm tsis ua hauj lwm.
AC cables tsis pom qhov tshwm sim no. Hauv cov ntsiab lus yooj yim, qhov kev ntxhov siab ntawm AC cable cov ntaub ntawv yog sib npaug, thaum nyob rau hauv DC cables, lub rwb thaiv tsev kev ntxhov siab yog ib txwm muaj zog ntawm cov ntsiab lus tsis muaj zog. Yog li, cov txheej txheem tsim khoom thiab cov qauv rau AC thiab DC cables yuav tsum tau tswj hwm qhov sib txawv.
Hla-txuas polyethylene (XLPE)insulated cables yog dav siv nyob rau hauv AC daim ntaub ntawv vim lawv zoo heev dielectric thiab lub cev zog, nrog rau lawv cov nqi-kev ua tau zoo piv. Txawm li cas los xij, thaum siv los ua DC cables, lawv ntsib qhov kev sib tw tseem ceeb ntsig txog qhov chaw them nqi, uas yog qhov tseem ceeb tshwj xeeb hauv high-voltage DC cables. Thaum cov khoom siv polymers siv los ua DC cable rwb thaiv tsev, ntau cov cuab yeej hauv zos hauv cov txheej txheem rwb thaiv tsev ua rau cov khoom seem ntawm qhov chaw. Qhov cuam tshuam ntawm qhov chaw tsub nqi ntawm cov ntaub ntawv rwb thaiv tsev yog feem ntau cuam tshuam rau ob yam: hluav taws xob hluav taws xob distortion thiab tsis muaj hluav taws xob cuam tshuam qhov cuam tshuam, ob qho tib si cuam tshuam rau cov khoom rwb thaiv tsev.
Qhov chaw them nqi yog hais txog tus nqi tshaj li hluav taws xob nruab nrab hauv ib chav tsev ntawm cov khoom siv macroscopic. Hauv cov khib nyiab, qhov zoo lossis qhov tsis zoo ntawm qhov chaw raug khi rau hauv cheeb tsam lub zog, muab cov teebmeem polarization hauv daim ntawv ntawm cov polarons khi. Qhov chaw them nqi polarization tshwm sim thaum cov ions dawb nyob hauv cov khoom siv dielectric. Vim lub zog ion, cov ions tsis zoo sib sau ua ke ntawm qhov sib txuas ze ntawm qhov zoo electrode, thiab cov ions zoo sib sau ua ke ntawm qhov cuam tshuam ze ntawm qhov tsis zoo electrode. Hauv qhov chaw hluav taws xob AC, kev tsiv teb tsaws ntawm cov nqi zoo thiab qhov tsis zoo tsis tuaj yeem ua raws li cov kev hloov pauv sai hauv lub zog hluav taws xob zaus hluav taws xob, yog li qhov chaw them nqi tsis tshwm sim. Nyob rau hauv DC hluav taws xob teb, txawm li cas los xij, cov hluav taws xob hluav taws xob faib raws li kev tiv thaiv, ua rau tsim cov nqi hluav taws xob thiab cuam tshuam rau hluav taws xob xa hluav taws xob. XLPE rwb thaiv tsev muaj ntau lub xeev hauv cheeb tsam, ua rau qhov chaw them nqi cuam tshuam loj heev.
XLPE rwb thaiv tsev yog chemically cross-linked, tsim ib qho kev sib txuas sib txuas. Raws li ib tug tsis-polar polymer, lub cable nws tus kheej yuav muab piv rau ib tug loj capacitor. Thaum DC kis tau tus mob nres, nws yog sib npaug rau them lub capacitor. Txawm hais tias tus neeg xyuas pib yog hauv av, qhov kev tso tawm zoo tsis tshwm sim, tawm hauv qhov tseem ceeb ntawm DC lub zog khaws cia rau hauv cable raws li qhov chaw them nqi. Tsis zoo li AC fais fab cables, qhov chaw tsub nqi yog dissipated los ntawm dielectric losses, cov nqi no accumulates nyob rau hauv lub cable.
Sij hawm dhau mus, nrog kev cuam tshuam ntawm lub zog tsis tu ncua lossis kev hloov pauv hauv lub zog tam sim no, XLPE insulated cables khaws ntau thiab ntau qhov chaw tsub, ua kom cov txheej txheem kev laus thiab txo cov kev pab cuam lub neej ntawm cable.
Lub sij hawm xa tuaj: Mar-10-2025